Commit Graph

2114 Commits

Author SHA1 Message Date
Linus Torvalds
d936eb2387 Revert "Makefile: Enable -Wimplicit-fallthrough for Clang"
This reverts commit b7eb335e26.

It turns out that the problem with the clang -Wimplicit-fallthrough
warning is not about the kernel source code, but about clang itself, and
that the warning is unusable until clang fixes its broken ways.

In particular, when you enable this warning for clang, you not only get
warnings about implicit fallthroughs.  You also get this:

   warning: fallthrough annotation in unreachable code [-Wimplicit-fallthrough]

which is completely broken becasue it

 (a) doesn't even tell you where the problem is (seriously: no line
     numbers, no filename, no nothing).

 (b) is fundamentally broken anyway, because there are perfectly valid
     reasons to have a fallthrough statement even if it turns out that
     it can perhaps not be reached.

In the kernel, an example of that second case is code in the scheduler:

                switch (state) {
                case cpuset:
                        if (IS_ENABLED(CONFIG_CPUSETS)) {
                                cpuset_cpus_allowed_fallback(p);
                                state = possible;
                                break;
                        }
                        fallthrough;
                case possible:

where if CONFIG_CPUSETS is enabled you actually never hit the
fallthrough case at all.  But that in no way makes the fallthrough
wrong.

So the warning is completely broken, and enabling it for clang is a very
bad idea.

In the meantime, we can keep the gcc option enabled, and make the gcc
build use

    -Wimplicit-fallthrough=5

which means that we will at least continue to require a proper
fallthrough statement, and that gcc won't silently accept the magic
comment versions. Because gcc does this all correctly, and while the odd
"=5" part is kind of obscure, it's documented in [1]:

  "-Wimplicit-fallthrough=5 doesn’t recognize any comments as
   fallthrough comments, only attributes disable the warning"

so if clang ever fixes its bad behavior we can try enabling it there again.

Link: https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html [1]
Cc: Kees Cook <keescook@chromium.org>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-15 18:05:31 -07:00
Gustavo A. R. Silva
b7eb335e26 Makefile: Enable -Wimplicit-fallthrough for Clang
With the recent fixes for fallthrough warnings, it is now possible to
enable -Wimplicit-fallthrough for Clang.

It's important to mention that since we have adopted the use of the
pseudo-keyword macro fallthrough; we also want to avoid having more
/* fall through */ comments being introduced. Notice that contrary
to GCC, Clang doesn't recognize any comments as implicit fall-through
markings when the -Wimplicit-fallthrough option is enabled. So, in
order to avoid having more comments being introduced, we have to use
the option -Wimplicit-fallthrough=5 for GCC, which similar to Clang,
will cause a warning in case a code comment is intended to be used
as a fall-through marking.

Co-developed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2021-07-14 11:12:21 -05:00
Linus Torvalds
e73f0f0ee7 Linux 5.14-rc1 2021-07-11 15:07:40 -07:00
Linus Torvalds
81361b837a Kbuild updates for v5.14
- Increase the -falign-functions alignment for the debug option.
 
  - Remove ugly libelf checks from the top Makefile.
 
  - Make the silent build (-s) more silent.
 
  - Re-compile the kernel if KBUILD_BUILD_TIMESTAMP is specified.
 
  - Various script cleanups
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Merge tag 'kbuild-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Increase the -falign-functions alignment for the debug option.

 - Remove ugly libelf checks from the top Makefile.

 - Make the silent build (-s) more silent.

 - Re-compile the kernel if KBUILD_BUILD_TIMESTAMP is specified.

 - Various script cleanups

* tag 'kbuild-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (27 commits)
  scripts: add generic syscallnr.sh
  scripts: check duplicated syscall number in syscall table
  sparc: syscalls: use pattern rules to generate syscall headers
  parisc: syscalls: use pattern rules to generate syscall headers
  nds32: add arch/nds32/boot/.gitignore
  kbuild: mkcompile_h: consider timestamp if KBUILD_BUILD_TIMESTAMP is set
  kbuild: modpost: Explicitly warn about unprototyped symbols
  kbuild: remove trailing slashes from $(KBUILD_EXTMOD)
  kconfig.h: explain IS_MODULE(), IS_ENABLED()
  kconfig: constify long_opts
  scripts/setlocalversion: simplify the short version part
  scripts/setlocalversion: factor out 12-chars hash construction
  scripts/setlocalversion: add more comments to -dirty flag detection
  scripts/setlocalversion: remove workaround for old make-kpkg
  scripts/setlocalversion: remove mercurial, svn and git-svn supports
  kbuild: clean up ${quiet} checks in shell scripts
  kbuild: sink stdout from cmd for silent build
  init: use $(call cmd,) for generating include/generated/compile.h
  kbuild: merge scripts/mkmakefile to top Makefile
  sh: move core-y in arch/sh/Makefile to arch/sh/Kbuild
  ...
2021-07-10 11:01:38 -07:00
Linus Torvalds
9840cfcb97 arm64 updates for 5.14
- Optimise SVE switching for CPUs with 128-bit implementations.
 
  - Fix output format from SVE selftest.
 
  - Add support for versions v1.2 and 1.3 of the SMC calling convention.
 
  - Allow Pointer Authentication to be configured independently for
    kernel and userspace.
 
  - PMU driver cleanups for managing IRQ affinity and exposing event
    attributes via sysfs.
 
  - KASAN optimisations for both hardware tagging (MTE) and out-of-line
    software tagging implementations.
 
  - Relax frame record alignment requirements to facilitate 8-byte
    alignment with KASAN and Clang.
 
  - Cleanup of page-table definitions and removal of unused memory types.
 
  - Reduction of ARCH_DMA_MINALIGN back to 64 bytes.
 
  - Refactoring of our instruction decoding routines and addition of some
    missing encodings.
 
  - Move entry code moved into C and hardened against harmful compiler
    instrumentation.
 
  - Update booting requirements for the FEAT_HCX feature, added to v8.7
    of the architecture.
 
  - Fix resume from idle when pNMI is being used.
 
  - Additional CPU sanity checks for MTE and preparatory changes for
    systems where not all of the CPUs support 32-bit EL0.
 
  - Update our kernel string routines to the latest Cortex Strings
    implementation.
 
  - Big cleanup of our cache maintenance routines, which were confusingly
    named and inconsistent in their implementations.
 
  - Tweak linker flags so that GDB can understand vmlinux when using RELR
    relocations.
 
  - Boot path cleanups to enable early initialisation of per-cpu
    operations needed by KCSAN.
 
  - Non-critical fixes and miscellaneous cleanup.
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Will Deacon:
 "There's a reasonable amount here and the juicy details are all below.

  It's worth noting that the MTE/KASAN changes strayed outside of our
  usual directories due to core mm changes and some associated changes
  to some other architectures; Andrew asked for us to carry these [1]
  rather that take them via the -mm tree.

  Summary:

   - Optimise SVE switching for CPUs with 128-bit implementations.

   - Fix output format from SVE selftest.

   - Add support for versions v1.2 and 1.3 of the SMC calling
     convention.

   - Allow Pointer Authentication to be configured independently for
     kernel and userspace.

   - PMU driver cleanups for managing IRQ affinity and exposing event
     attributes via sysfs.

   - KASAN optimisations for both hardware tagging (MTE) and out-of-line
     software tagging implementations.

   - Relax frame record alignment requirements to facilitate 8-byte
     alignment with KASAN and Clang.

   - Cleanup of page-table definitions and removal of unused memory
     types.

   - Reduction of ARCH_DMA_MINALIGN back to 64 bytes.

   - Refactoring of our instruction decoding routines and addition of
     some missing encodings.

   - Move entry code moved into C and hardened against harmful compiler
     instrumentation.

   - Update booting requirements for the FEAT_HCX feature, added to v8.7
     of the architecture.

   - Fix resume from idle when pNMI is being used.

   - Additional CPU sanity checks for MTE and preparatory changes for
     systems where not all of the CPUs support 32-bit EL0.

   - Update our kernel string routines to the latest Cortex Strings
     implementation.

   - Big cleanup of our cache maintenance routines, which were
     confusingly named and inconsistent in their implementations.

   - Tweak linker flags so that GDB can understand vmlinux when using
     RELR relocations.

   - Boot path cleanups to enable early initialisation of per-cpu
     operations needed by KCSAN.

   - Non-critical fixes and miscellaneous cleanup"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (150 commits)
  arm64: tlb: fix the TTL value of tlb_get_level
  arm64: Restrict undef hook for cpufeature registers
  arm64/mm: Rename ARM64_SWAPPER_USES_SECTION_MAPS
  arm64: insn: avoid circular include dependency
  arm64: smp: Bump debugging information print down to KERN_DEBUG
  drivers/perf: fix the missed ida_simple_remove() in ddr_perf_probe()
  perf/arm-cmn: Fix invalid pointer when access dtc object sharing the same IRQ number
  arm64: suspend: Use cpuidle context helpers in cpu_suspend()
  PSCI: Use cpuidle context helpers in psci_cpu_suspend_enter()
  arm64: Convert cpu_do_idle() to using cpuidle context helpers
  arm64: Add cpuidle context save/restore helpers
  arm64: head: fix code comments in set_cpu_boot_mode_flag
  arm64: mm: drop unused __pa(__idmap_text_start)
  arm64: mm: fix the count comments in compute_indices
  arm64/mm: Fix ttbr0 values stored in struct thread_info for software-pan
  arm64: mm: Pass original fault address to handle_mm_fault()
  arm64/mm: Drop SECTION_[SHIFT|SIZE|MASK]
  arm64/mm: Use CONT_PMD_SHIFT for ARM64_MEMSTART_SHIFT
  arm64/mm: Drop SWAPPER_INIT_MAP_SIZE
  arm64: Conditionally configure PTR_AUTH key of the kernel.
  ...
2021-06-28 14:04:24 -07:00
Linus Torvalds
62fb9874f5 Linux 5.13 2021-06-27 15:21:11 -07:00
Linus Torvalds
13311e7425 Linux 5.13-rc7 2021-06-20 15:03:15 -07:00
Masahiro Yamada
74ee585b7e kbuild: remove trailing slashes from $(KBUILD_EXTMOD)
M= (or KBUILD_EXTMOD) generally expects a directory path without any
trailing slashes, like M=a/b/c.

If you add a trailing slash, like M=a/b/c/, you will get ugly build
logs (two slashes in a series), but it still works fine as long as it
is consistent between 'make modules' and 'make modules_install'.

The following commands correctly build and install the modules.

  $ make M=a/b/c/ modules
  $ sudo make M=a/b/c/ modules_install

Since commit ccae4cfa7b ("kbuild: refactor scripts/Makefile.modinst"),
a problem happens if you add a trailing slash only for modules_install.

  $ make M=a/b/c modules
  $ sudo make M=a/b/c/ modules_install

No module is installed in this case, Johannes Berg reported. [1]

Trim any trailing slashes from $(KBUILD_EXTMOD).

I used the 'dirname' command to remove all the trailing slashes in
case someone adds more slashes like M=a/b/c/////. The Make's built-in
function, $(dir ...) cannot take care of such a case.

[1]: https://lore.kernel.org/lkml/10cc8522b27a051e6a9c3e158a4c4b6414fd04a0.camel@sipsolutions.net/

Fixes: ccae4cfa7b ("kbuild: refactor scripts/Makefile.modinst")
Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-06-17 09:50:59 +09:00
Linus Torvalds
cc9aaa2b07 Clang feature fix for v5.13-rc7
- The "-warn-stack-size" option under LTO has moved in Clang 13 (Tor Vic)
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Merge tag 'clang-features-v5.13-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull clang LTO fix from Kees Cook:
 "It seems Clang has been scrubbing through the missing LTO IR flags for
  Clang 13, and the last of these 'only with LTO' flags is fixed now.

  I've asked that they please consider making these changes in a less
  'break all the Clang kernel builds' kind of way in the future. :P

  Summary:

   - The '-warn-stack-size' option under LTO has moved in Clang 13 (Tor
     Vic)"

* tag 'clang-features-v5.13-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  Makefile: lto: Pass -warn-stack-size only on LLD < 13.0.0
2021-06-16 08:57:44 -07:00
Tor Vic
0236526d76 Makefile: lto: Pass -warn-stack-size only on LLD < 13.0.0
Since LLVM commit fc018eb, the '-warn-stack-size' flag has been dropped
[1], leading to the following error message when building with Clang-13
and LLD-13:

    ld.lld: error: -plugin-opt=-: ld.lld: Unknown command line argument
    '-warn-stack-size=2048'.  Try: 'ld.lld --help'
    ld.lld: Did you mean '--asan-stack=2048'?

In the same way as with commit 2398ce8015 ("x86, lto: Pass
-stack-alignment only on LLD < 13.0.0") , make '-warn-stack-size'
conditional on LLD < 13.0.0.

[1] https://reviews.llvm.org/D103928

Fixes: 24845dcb17 ("Makefile: LTO: have linker check -Wframe-larger-than")
Cc: stable@vger.kernel.org
Link: https://github.com/ClangBuiltLinux/linux/issues/1377
Signed-off-by: Tor Vic <torvic9@mailbox.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/7631bab7-a8ab-f884-ab54-f4198976125c@mailbox.org
2021-06-14 14:52:38 -07:00
Linus Torvalds
009c9aa5be Linux 5.13-rc6 2021-06-13 14:43:10 -07:00
Nick Desaulniers
27f2a4db76 Makefile: fix GDB warning with CONFIG_RELR
GDB produces the following warning when debugging kernels built with
CONFIG_RELR:

BFD: /android0/linux-next/vmlinux: unknown type [0x13] section `.relr.dyn'

when loading a kernel built with CONFIG_RELR into GDB. It can also
prevent debugging symbols using such relocations.

Peter sugguests:
  [That flag] means that lld will use dynamic tags and section type
  numbers in the OS-specific range rather than the generic range. The
  kernel itself doesn't care about these numbers; it determines the
  location of the RELR section using symbols defined by a linker script.

Link: https://github.com/ClangBuiltLinux/linux/issues/1057
Suggested-by: Peter Collingbourne <pcc@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20210522012626.2811297-1-ndesaulniers@google.com
Signed-off-by: Will Deacon <will@kernel.org>
2021-06-08 13:09:34 +01:00
Linus Torvalds
614124bea7 Linux 5.13-rc5 2021-06-06 15:47:27 -07:00
Linus Torvalds
8124c8a6b3 Linux 5.13-rc4 2021-05-30 11:58:25 -10:00
Linus Torvalds
8508b97ae2 Clang feature fixes for v5.13-rc4
- Correctly pass stack frame size checking under LTO (Nick Desaulniers)
 
 - Avoid CFI mismatches by checking initcall_t types (Marco Elver)
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Merge tag 'clang-features-v5.13-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull clang feature fixes from Kees Cook:

 - Correctly pass stack frame size checking under LTO (Nick Desaulniers)

 - Avoid CFI mismatches by checking initcall_t types (Marco Elver)

* tag 'clang-features-v5.13-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  Makefile: LTO: have linker check -Wframe-larger-than
  init: verify that function is initcall_t at compile-time
2021-05-28 08:31:48 -10:00
Masahiro Yamada
2728fcfa4f kbuild: merge scripts/mkmakefile to top Makefile
scripts/mkmakefile is simple enough to be merged in the Makefile.

Use $(call cmd,...) to show the log instead of doing it in the
shell script.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-05-27 03:59:29 +09:00
Masahiro Yamada
d92cc4d516 kbuild: require all architectures to have arch/$(SRCARCH)/Kbuild
arch/$(SRCARCH)/Kbuild is useful for Makefile cleanups because you can
use the obj-y syntax.

Add an empty file if it is missing in arch/$(SRCARCH)/.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-05-26 23:10:37 +09:00
Nick Desaulniers
24845dcb17 Makefile: LTO: have linker check -Wframe-larger-than
-Wframe-larger-than= requires stack frame information, which the
frontend cannot provide. This diagnostic is emitted late during
compilation once stack frame size is available.

When building with LTO, the frontend simply lowers C to LLVM IR and does
not have stack frame information, so it cannot emit this diagnostic.
When the linker drives LTO, it restarts optimizations and lowers LLVM IR
to object code. At that point, it has stack frame information but
doesn't know to check for a specific max stack frame size.

I consider this a bug in LLVM that we need to fix. There are some
details we're working out related to LTO such as which value to use when
there are multiple different values specified per TU, or how to
propagate these to compiler synthesized routines properly, if at all.

Until it's fixed, ensure we don't miss these. At that point we can wrap
this in a compiler version guard or revert this based on the minimum
support version of Clang.

The error message is not generated during link:
  LTO     vmlinux.o
ld.lld: warning: stack size limit exceeded (8224) in foobarbaz

Cc: Sami Tolvanen <samitolvanen@google.com>
Reported-by: Candle Sun <candlesea@gmail.com>
Suggested-by: Fangrui Song <maskray@google.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210312010942.1546679-1-ndesaulniers@google.com
2021-05-24 15:24:34 -07:00
Masahiro Yamada
0d989ac2c9 kbuild: remove libelf checks from top Makefile
I do not see a good reason why only the libelf development package must
be so carefully checked.

Kbuild generally does not check host tools or libraries.

For example, x86_64 defconfig fails to build with no libssl development
package installed.

scripts/extract-cert.c:21:10: fatal error: openssl/bio.h: No such file or directory
   21 | #include <openssl/bio.h>
      |          ^~~~~~~~~~~~~~~

To solve the build error, you need to install libssl-dev or openssl-devel
package, depending on your distribution.

'apt-file search', 'dnf provides', etc. is your frined to find a proper
package to install.

This commit removes all the libelf checks from the top Makefile.

If libelf is missing, objtool will fail to build in a similar pattern:

.../linux/tools/objtool/include/objtool/elf.h:10:10: fatal error: gelf.h: No such file or directory
   10 | #include <gelf.h>

You need to install libelf-dev, libelf-devel, or elfutils-libelf-devel
to proceed.

Another remarkable change is, CONFIG_STACK_VALIDATION (without
CONFIG_UNWINDER_ORC) previously continued to build with a warning,
but now it will treat missing libelf as an error.

This is just a one-time installation, so it should not hurt to break
a build and make a user install the package.

BTW, the traditional way to handle such checks is autotool, but according
to [1], I do not expect the kernel build would have similar scripting
like './configure' does.

[1]: https://lore.kernel.org/lkml/CA+55aFzr2HTZVOuzpHYDwmtRJLsVzE-yqg2DHpHi_9ePsYp5ug@mail.gmail.com/

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
2021-05-24 12:06:51 +09:00
Masahiro Yamada
1bb0b18a06 kbuild: hide tools/ build targets from external module builds
The tools/ directory only exists in the kernel source tree, not in
external modules.

Do not expose the meaningless targets to external modules.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-05-24 12:06:51 +09:00
Feng Tang
cf536e1858 Makefile: extend 32B aligned debug option to 64B aligned
Commit 09c60546f0 ("./Makefile: add debug option to enable
function aligned on 32 bytes") was introduced to help debugging
strange kernel performance changes caused by code alignment
change.

Recently we found 2 similar cases [1][2] caused by code-alignment
changes, which can only be identified by forcing 64 bytes aligned
for all functions.

Originally, 32 bytes was used mainly for not wasting too much
text space, but this option is only for debug anyway where text
space is not a big concern. So extend the alignment to 64 bytes
to cover more similar cases.

[1].https://lore.kernel.org/lkml/20210427090013.GG32408@xsang-OptiPlex-9020/
[2].https://lore.kernel.org/lkml/20210420030837.GB31773@xsang-OptiPlex-9020/
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-05-24 12:06:50 +09:00
Linus Torvalds
c4681547bc Linux 5.13-rc3 2021-05-23 11:42:48 -10:00
Linus Torvalds
d07f6ca923 Linux 5.13-rc2 2021-05-16 15:27:44 -07:00
Linus Torvalds
6efb943b86 Linux 5.13-rc1 2021-05-09 14:17:44 -07:00
Linus Torvalds
0f979d815c Kbuild updates for v5.13 (2nd)
- Convert sh and sparc to use generic shell scripts to generate the
    syscall headers
 
  - refactor .gitignore files
 
  - Update kernel/config_data.gz only when the content of the .config is
    really changed, which avoids the unneeded re-link of vmlinux
 
  - move "remove stale files" workarounds to scripts/remove-stale-files
 
  - suppress unused-but-set-variable warnings by default for Clang as well
 
  - fix locale setting LANG=C to LC_ALL=C
 
  - improve 'make distclean'
 
  - always keep intermediate objects from scripts/link-vmlinux.sh
 
  - move IF_ENABLED out of <linux/kconfig.h> to make it self-contained
 
  - misc cleanups
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Merge tag 'kbuild-v5.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull more Kbuild updates from Masahiro Yamada:

 - Convert sh and sparc to use generic shell scripts to generate the
   syscall headers

 - refactor .gitignore files

 - Update kernel/config_data.gz only when the content of the .config
   is really changed, which avoids the unneeded re-link of vmlinux

 - move "remove stale files" workarounds to scripts/remove-stale-files

 - suppress unused-but-set-variable warnings by default for Clang
   as well

 - fix locale setting LANG=C to LC_ALL=C

 - improve 'make distclean'

 - always keep intermediate objects from scripts/link-vmlinux.sh

 - move IF_ENABLED out of <linux/kconfig.h> to make it self-contained

 - misc cleanups

* tag 'kbuild-v5.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (25 commits)
  linux/kconfig.h: replace IF_ENABLED() with PTR_IF() in <linux/kernel.h>
  kbuild: Don't remove link-vmlinux temporary files on exit/signal
  kbuild: remove the unneeded comments for external module builds
  kbuild: make distclean remove tag files in sub-directories
  kbuild: make distclean work against $(objtree) instead of $(srctree)
  kbuild: refactor modname-multi by using suffix-search
  kbuild: refactor fdtoverlay rule
  kbuild: parameterize the .o part of suffix-search
  arch: use cross_compiling to check whether it is a cross build or not
  kbuild: remove ARCH=sh64 support from top Makefile
  .gitignore: prefix local generated files with a slash
  kbuild: replace LANG=C with LC_ALL=C
  Makefile: Move -Wno-unused-but-set-variable out of GCC only block
  kbuild: add a script to remove stale generated files
  kbuild: update config_data.gz only when the content of .config is changed
  .gitignore: ignore only top-level modules.builtin
  .gitignore: move tags and TAGS close to other tag files
  kernel/.gitgnore: remove stale timeconst.h and hz.bc
  usr/include: refactor .gitignore
  genksyms: fix stale comment
  ...
2021-05-08 10:00:11 -07:00
Masahiro Yamada
11122b860b kbuild: remove the unneeded comments for external module builds
The supported targets for external modules are listed in the help target
a few lines below. Let's not have duplicated information in two places.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-05-06 02:16:25 +09:00
Masahiro Yamada
7a02cec523 kbuild: make distclean remove tag files in sub-directories
'make tags' and friends create tag files in the top directory, but
people may manually create tag files in sub-directories.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-05-06 02:16:08 +09:00
Masahiro Yamada
19c8d91283 kbuild: make distclean work against $(objtree) instead of $(srctree)
This reverts the old commit [1], which seems questionable to me.

It claimed 'make distclean' could not remove editor backup files,
but I believe KBUILD_OUTPUT or O= was set.

When O= is given, Kbuild should always work against $(objtree).
If O= is not given, $(objtree) and $(srctree) are the same, therefore
$(srctree) is cleaned up.

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=dd47df980c02eb33833b2690b033c34fba2fa80d

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-05-06 02:15:46 +09:00
Masahiro Yamada
45799491a9 kbuild: remove ARCH=sh64 support from top Makefile
Commit 37744feebc ("sh: remove sh5 support") removed the SUPERH64
support entirely.

Remove the left-over code from the top Makefile.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
2021-05-03 18:20:24 +09:00
Linus Torvalds
e6f0bf09f0 integrity-v5.13
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Merge tag 'integrity-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity

Pull IMA updates from Mimi Zohar:
 "In addition to loading the kernel module signing key onto the builtin
  keyring, load it onto the IMA keyring as well.

  Also six trivial changes and bug fixes"

* tag 'integrity-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  ima: ensure IMA_APPRAISE_MODSIG has necessary dependencies
  ima: Fix fall-through warnings for Clang
  integrity: Add declarations to init_once void arguments.
  ima: Fix function name error in comment.
  ima: enable loading of build time generated key on .ima keyring
  ima: enable signing of modules with build time generated key
  keys: cleanup build time module signing keys
  ima: Fix the error code for restoring the PCR value
  ima: without an IMA policy loaded, return quickly
2021-05-01 15:32:18 -07:00
Nathan Chancellor
885480b084 Makefile: Move -Wno-unused-but-set-variable out of GCC only block
Currently, -Wunused-but-set-variable is only supported by GCC so it is
disabled unconditionally in a GCC only block (it is enabled with W=1).
clang currently has its implementation for this warning in review so
preemptively move this statement out of the GCC only block and wrap it
with cc-disable-warning so that both compilers function the same.

Cc: stable@vger.kernel.org
Link: https://reviews.llvm.org/D100581
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-05-02 00:43:35 +09:00
Masahiro Yamada
1476fee5c5 kbuild: add a script to remove stale generated files
We maintain .gitignore and Makefiles so build artifacts are properly
ignored by Git, and cleaned up by 'make clean'. However, the code is
always changing; generated files are often moved to another directory,
or removed when they become unnecessary. Such garbage files tend to be
left over in the source tree because people usually git-pull without
cleaning the tree.

This is not only the noise for 'git status', but also a build issue
in some cases.

One solution is to remove a stale file like commit 223c24a7db ("kbuild:
Automatically remove stale <linux/version.h> file") did. Such workaround
should be removed after a while, but we forget about that if we scatter
the workaround code in random places.

So, this commit adds a new script to collect cleanings of stale files.

As a start point, move the code in arch/arm/boot/compressed/Makefile
into this script.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-05-02 00:43:35 +09:00
Linus Torvalds
8ca5297e7e Kconfig updates for v5.13
- Change 'option defconfig' to the environment variable
    KCONFIG_DEFCONFIG_LIST
 
  - Refactor tinyconfig without using allnoconfig_y
 
  - Remove 'option allnoconfig_y' syntax
 
  - Change 'option modules' to 'modules'
 
  - Do not use /boot/config-* etc. as base config for cross-compilation
 
  - Fix a search bug in nconf
 
  - Various code cleanups
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Merge tag 'kconfig-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kconfig updates from Masahiro Yamada:

 - Change 'option defconfig' to the environment variable
   KCONFIG_DEFCONFIG_LIST

 - Refactor tinyconfig without using allnoconfig_y

 - Remove 'option allnoconfig_y' syntax

 - Change 'option modules' to 'modules'

 - Do not use /boot/config-* etc. as base config for cross-compilation

 - Fix a search bug in nconf

 - Various code cleanups

* tag 'kconfig-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (34 commits)
  kconfig: refactor .gitignore
  kconfig: highlight xconfig 'comment' lines with '***'
  kconfig: highlight gconfig 'comment' lines with '***'
  kconfig: gconf: remove unused code
  kconfig: remove unused PACKAGE definition
  kconfig: nconf: stop endless search loops
  kconfig: split menu.c out of parser.y
  kconfig: nconf: refactor in print_in_middle()
  kconfig: nconf: remove meaningless wattrset() call from show_menu()
  kconfig: nconf: change set_config_filename() to void function
  kconfig: nconf: refactor attributes setup code
  kconfig: nconf: remove unneeded default for menu prompt
  kconfig: nconf: get rid of (void) casts from wattrset() calls
  kconfig: nconf: fix NORMAL attributes
  kconfig: mconf,nconf: remove unneeded '\0' termination after snprintf()
  kconfig: use /boot/config-* etc. as DEFCONFIG_LIST only for native build
  kconfig: change sym_change_count to a boolean flag
  kconfig: nconf: fix core dump when searching in empty menu
  kconfig: lxdialog: A spello fix and a punctuation added
  kconfig: streamline_config.pl: Couple of typo fixes
  ...
2021-04-29 14:32:00 -07:00
Linus Torvalds
b0030af53a Kbuild updates for v5.13
- Evaluate $(call cc-option,...) etc. only for build targets
 
  - Add CONFIG_VMLINUX_MAP to generate .map file when linking vmlinux
 
  - Remove unnecessary --gcc-toolchains Clang flag because the --prefix
    flag finds the toolchains
 
  - Do not pass Clang's --prefix flag when using the integrated as
 
  - Check the assembler version in Kconfig time
 
  - Add new CONFIG options, AS_VERSION, AS_IS_GNU, AS_IS_LLVM to clean up
    some dependencies in Kconfig
 
  - Fix invalid Module.symvers creation when building only modules without
    vmlinux
 
  - Fix false-positive modpost warnings when CONFIG_TRIM_UNUSED_KSYMS is
    set, but there is no module to build
 
  - Refactor module installation Makefile
 
  - Support zstd for module compression
 
  - Convert alpha and ia64 to use generic shell scripts to generate the
    syscall headers
 
  - Add a new elfnote to indicate if the kernel was built with LTO, which
    will be used by pahole
 
  - Flatten the directory structure under include/config/ so CONFIG options
    and filenames match
 
  - Change the deb source package name from linux-$(KERNELRELEASE) to
    linux-upstream
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Merge tag 'kbuild-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Evaluate $(call cc-option,...) etc. only for build targets

 - Add CONFIG_VMLINUX_MAP to generate .map file when linking vmlinux

 - Remove unnecessary --gcc-toolchains Clang flag because the --prefix
   flag finds the toolchains

 - Do not pass Clang's --prefix flag when using the integrated as

 - Check the assembler version in Kconfig time

 - Add new CONFIG options, AS_VERSION, AS_IS_GNU, AS_IS_LLVM to clean up
   some dependencies in Kconfig

 - Fix invalid Module.symvers creation when building only modules
   without vmlinux

 - Fix false-positive modpost warnings when CONFIG_TRIM_UNUSED_KSYMS is
   set, but there is no module to build

 - Refactor module installation Makefile

 - Support zstd for module compression

 - Convert alpha and ia64 to use generic shell scripts to generate the
   syscall headers

 - Add a new elfnote to indicate if the kernel was built with LTO, which
   will be used by pahole

 - Flatten the directory structure under include/config/ so CONFIG
   options and filenames match

 - Change the deb source package name from linux-$(KERNELRELEASE) to
   linux-upstream

* tag 'kbuild-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (42 commits)
  kbuild: Add $(KBUILD_HOSTLDFLAGS) to 'has_libelf' test
  kbuild: deb-pkg: change the source package name to linux-upstream
  tools: do not include scripts/Kbuild.include
  kbuild: redo fake deps at include/config/*.h
  kbuild: remove TMPO from try-run
  MAINTAINERS: add pattern for dummy-tools
  kbuild: add an elfnote for whether vmlinux is built with lto
  ia64: syscalls: switch to generic syscallhdr.sh
  ia64: syscalls: switch to generic syscalltbl.sh
  alpha: syscalls: switch to generic syscallhdr.sh
  alpha: syscalls: switch to generic syscalltbl.sh
  sysctl: use min() helper for namecmp()
  kbuild: add support for zstd compressed modules
  kbuild: remove CONFIG_MODULE_COMPRESS
  kbuild: merge scripts/Makefile.modsign to scripts/Makefile.modinst
  kbuild: move module strip/compression code into scripts/Makefile.modinst
  kbuild: refactor scripts/Makefile.modinst
  kbuild: rename extmod-prefix to extmod_prefix
  kbuild: check module name conflict for external modules as well
  kbuild: show the target directory for depmod log
  ...
2021-04-29 14:24:39 -07:00
Linus Torvalds
57fa2369ab CFI on arm64 series for v5.13-rc1
- Clean up list_sort prototypes (Sami Tolvanen)
 
 - Introduce CONFIG_CFI_CLANG for arm64 (Sami Tolvanen)
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Merge tag 'cfi-v5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull CFI on arm64 support from Kees Cook:
 "This builds on last cycle's LTO work, and allows the arm64 kernels to
  be built with Clang's Control Flow Integrity feature. This feature has
  happily lived in Android kernels for almost 3 years[1], so I'm excited
  to have it ready for upstream.

  The wide diffstat is mainly due to the treewide fixing of mismatched
  list_sort prototypes. Other things in core kernel are to address
  various CFI corner cases. The largest code portion is the CFI runtime
  implementation itself (which will be shared by all architectures
  implementing support for CFI). The arm64 pieces are Acked by arm64
  maintainers rather than coming through the arm64 tree since carrying
  this tree over there was going to be awkward.

  CFI support for x86 is still under development, but is pretty close.
  There are a handful of corner cases on x86 that need some improvements
  to Clang and objtool, but otherwise works well.

  Summary:

   - Clean up list_sort prototypes (Sami Tolvanen)

   - Introduce CONFIG_CFI_CLANG for arm64 (Sami Tolvanen)"

* tag 'cfi-v5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  arm64: allow CONFIG_CFI_CLANG to be selected
  KVM: arm64: Disable CFI for nVHE
  arm64: ftrace: use function_nocfi for ftrace_call
  arm64: add __nocfi to __apply_alternatives
  arm64: add __nocfi to functions that jump to a physical address
  arm64: use function_nocfi with __pa_symbol
  arm64: implement function_nocfi
  psci: use function_nocfi for cpu_resume
  lkdtm: use function_nocfi
  treewide: Change list_sort to use const pointers
  bpf: disable CFI in dispatcher functions
  kallsyms: strip ThinLTO hashes from static functions
  kthread: use WARN_ON_FUNCTION_MISMATCH
  workqueue: use WARN_ON_FUNCTION_MISMATCH
  module: ensure __cfi_check alignment
  mm: add generic function_nocfi macro
  cfi: add __cficanonical
  add support for Clang CFI
2021-04-27 10:16:46 -07:00
Linus Torvalds
eea2647e74 Entry code update:
Provide support for randomized stack offsets per syscall to make
  stack-based attacks harder which rely on the deterministic stack layout.
 
  The feature is based on the original idea of PaX's RANDSTACK feature, but
  uses a significantly different implementation.
 
  The offset does not affect the pt_regs location on the task stack as this
  was agreed on to be of dubious value. The offset is applied before the
  actual syscall is invoked.
 
  The offset is stored per cpu and the randomization happens at the end of
  the syscall which is less predictable than on syscall entry.
 
  The mechanism to apply the offset is via alloca(), i.e. abusing the
  dispised VLAs. This comes with the drawback that stack-clash-protection
  has to be disabled for the affected compilation units and there is also
  a negative interaction with stack-protector.
 
  Those downsides are traded with the advantage that this approach does not
  require any intrusive changes to the low level assembly entry code, does
  not affect the unwinder and the correct stack alignment is handled
  automatically by the compiler.
 
  The feature is guarded with a static branch which avoids the overhead when
  disabled.
 
  Currently this is supported for X86 and ARM64.
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Merge tag 'x86-entry-2021-04-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull entry code update from Thomas Gleixner:
 "Provide support for randomized stack offsets per syscall to make
  stack-based attacks harder which rely on the deterministic stack
  layout.

  The feature is based on the original idea of PaX's RANDSTACK feature,
  but uses a significantly different implementation.

  The offset does not affect the pt_regs location on the task stack as
  this was agreed on to be of dubious value. The offset is applied
  before the actual syscall is invoked.

  The offset is stored per cpu and the randomization happens at the end
  of the syscall which is less predictable than on syscall entry.

  The mechanism to apply the offset is via alloca(), i.e. abusing the
  dispised VLAs. This comes with the drawback that
  stack-clash-protection has to be disabled for the affected compilation
  units and there is also a negative interaction with stack-protector.

  Those downsides are traded with the advantage that this approach does
  not require any intrusive changes to the low level assembly entry
  code, does not affect the unwinder and the correct stack alignment is
  handled automatically by the compiler.

  The feature is guarded with a static branch which avoids the overhead
  when disabled.

  Currently this is supported for X86 and ARM64"

* tag 'x86-entry-2021-04-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  arm64: entry: Enable random_kstack_offset support
  lkdtm: Add REPORT_STACK for checking stack offsets
  x86/entry: Enable random_kstack_offset support
  stack: Optionally randomize kernel stack offset each syscall
  init_on_alloc: Optimize static branches
  jump_label: Provide CONFIG-driven build state defaults
2021-04-26 10:02:09 -07:00
Linus Torvalds
9f4ad9e425 Linux 5.12 2021-04-25 13:49:08 -07:00
Nathan Chancellor
f634ca650f kbuild: Add $(KBUILD_HOSTLDFLAGS) to 'has_libelf' test
Normally, invocations of $(HOSTCC) include $(KBUILD_HOSTLDFLAGS), which
in turn includes $(HOSTLDFLAGS), which allows users to pass in their own
flags when linking. However, the 'has_libelf' test does not, meaning
that if a user requests a specific linker via HOSTLDFLAGS=-fuse-ld=...,
it is not respected and the build might error.

For example, if a user building with clang wants to use all of the LLVM
tools without any GNU tools, they might remove all of the GNU tools from
their system or PATH then build with

$ make HOSTLDFLAGS=-fuse-ld=lld LLVM=1 LLVM_IAS=1

which says use all of the LLVM tools, the integrated assembler, and
ld.lld for linking host executables. Without this change, the build will
error because $(HOSTCC) uses its default linker, rather than the one
requested via -fuse-ld=..., which is GNU ld in clang's case in a default
configuration.

error: Cannot generate ORC metadata for CONFIG_UNWINDER_ORC=y, please
install libelf-dev, libelf-devel or elfutils-libelf-devel
make[1]: *** [Makefile:1260: prepare-objtool] Error 1

Add $(KBUILD_HOSTLDFLAGS) to the 'has_libelf' test so that the linker
choice is respected.

Link: https://github.com/ClangBuiltLinux/linux/issues/479
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 06:14:56 +09:00
Masahiro Yamada
961ab4a3cd kbuild: merge scripts/Makefile.modsign to scripts/Makefile.modinst
scripts/Makefile.modsign is a subset of scripts/Makefile.modinst,
and duplicates the code. Let's merge them.

By the way, you do not need to run 'make modules_sign' explicitly
because modules are signed as a part of 'make modules_install' when
CONFIG_MODULE_SIG_ALL=y. If CONFIG_MODULE_SIG_ALL=n, mod_sign_cmd is
set to 'true', so 'make modules_sign' is not functional.

In my understanding, the reason of still keeping this is to handle
corner cases like commit 64178cb62c ("builddeb: fix stripped module
signatures if CONFIG_DEBUG_INFO and CONFIG_MODULE_SIG_ALL are set").

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 05:23:57 +09:00
Masahiro Yamada
65ce9c3832 kbuild: move module strip/compression code into scripts/Makefile.modinst
Both mod_strip_cmd and mod_compress_cmd are only used in
scripts/Makefile.modinst, hence there is no good reason to define them
in the top Makefile. Move the relevant code to scripts/Makefile.modinst.

Also, show separate log messages for each of install, strip, sign, and
compress.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 05:23:36 +09:00
Masahiro Yamada
ccae4cfa7b kbuild: refactor scripts/Makefile.modinst
scripts/Makefile.modinst is ugly and weird in multiple ways; it
specifies real files $(modules) as phony, makes directory manipulation
needlessly too complicated.

Clean up the Makefile code, and show the full path of installed modules
in the log.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 05:23:17 +09:00
Masahiro Yamada
7f69180b8e kbuild: rename extmod-prefix to extmod_prefix
This seems to be useful in sub-make as well. As a preparation of
exporting it, rename extmod-prefix to extmod_prefix because exported
variables cannot contain hyphens.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2021-04-25 05:23:00 +09:00
Masahiro Yamada
1a998be620 kbuild: check module name conflict for external modules as well
If there are multiple modules with the same name in the same external
module tree, there is ambiguity about which one will be loaded, and
very likely something odd is happening.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 05:22:42 +09:00
Masahiro Yamada
3ac42b2112 kbuild: show the target directory for depmod log
It is clearer to show the directory which depmod will work on.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 05:22:26 +09:00
Masahiro Yamada
3e3005df73 kbuild: unify modules(_install) for in-tree and external modules
If you attempt to build or install modules ('make modules(_install)'
with CONFIG_MODULES disabled, you will get a clear error message, but
nothing for external module builds.

Factor out the modules and modules_install rules into the common part,
so you will get the same error message when you try to build external
modules with CONFIG_MODULES=n.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 05:21:58 +09:00
Masahiro Yamada
4b97ec0e9c kbuild: remove unneeded mkdir for external modules_install
scripts/Makefile.modinst creates directories as needed.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 05:21:50 +09:00
Masahiro Yamada
69bc8d386a kbuild: generate Module.symvers only when vmlinux exists
The external module build shows the following warning if Module.symvers
is missing in the kernel tree.

  WARNING: Symbol version dump "Module.symvers" is missing.
           Modules may not have dependencies or modversions.

I think this is an important heads-up because the resulting modules may
not work as expected. This happens when you did not build the entire
kernel tree, for example, you might have prepared the minimal setups
for external modules by 'make defconfig && make modules_preapre'.

A problem is that 'make modules' creates Module.symvers even without
vmlinux. In this case, that warning is suppressed since Module.symvers
already exists in spite of its incomplete content.

The incomplete (i.e. invalid) Module.symvers should not be created.

This commit changes the second pass of modpost to dump symbols into
modules-only.symvers. The final Module.symvers is created by
concatenating vmlinux.symvers and modules-only.symvers if both exist.

Module.symvers is supposed to collect symbols from both vmlinux and
modules. It might be a bit confusing, and I am not quite sure if it
is an official interface, but presumably it is difficult to rename it
because some tools (e.g. kmod) parse it.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 05:17:02 +09:00
Masahiro Yamada
ba64beb174 kbuild: check the minimum assembler version in Kconfig
Documentation/process/changes.rst defines the minimum assembler version
(binutils version), but we have never checked it in the build time.

Kbuild never invokes 'as' directly because all assembly files in the
kernel tree are *.S, hence must be preprocessed. I do not expect
raw assembly source files (*.s) would be added to the kernel tree.

Therefore, we always use $(CC) as the assembler driver, and commit
aa824e0c96 ("kbuild: remove AS variable") removed 'AS'. However,
we are still interested in the version of the assembler acting behind.

As usual, the --version option prints the version string.

  $ as --version | head -n 1
  GNU assembler (GNU Binutils for Ubuntu) 2.35.1

But, we do not have $(AS). So, we can add the -Wa prefix so that
$(CC) passes --version down to the backing assembler.

  $ gcc -Wa,--version | head -n 1
  gcc: fatal error: no input files
  compilation terminated.

OK, we need to input something to satisfy gcc.

  $ gcc -Wa,--version -c -x assembler /dev/null -o /dev/null | head -n 1
  GNU assembler (GNU Binutils for Ubuntu) 2.35.1

The combination of Clang and GNU assembler works in the same way:

  $ clang -no-integrated-as -Wa,--version -c -x assembler /dev/null -o /dev/null | head -n 1
  GNU assembler (GNU Binutils for Ubuntu) 2.35.1

Clang with the integrated assembler fails like this:

  $ clang -integrated-as -Wa,--version -c -x assembler /dev/null -o /dev/null | head -n 1
  clang: error: unsupported argument '--version' to option 'Wa,'

For the last case, checking the error message is fragile. If the
proposal for -Wa,--version support [1] is accepted, this may not be
even an error in the future.

One easy way is to check if -integrated-as is present in the passed
arguments. We did not pass -integrated-as to CLANG_FLAGS before, but
we can make it explicit.

Nathan pointed out -integrated-as is the default for all of the
architectures/targets that the kernel cares about, but it goes
along with "explicit is better than implicit" policy. [2]

With all this in my mind, I implemented scripts/as-version.sh to
check the assembler version in Kconfig time.

  $ scripts/as-version.sh gcc
  GNU 23501
  $ scripts/as-version.sh clang -no-integrated-as
  GNU 23501
  $ scripts/as-version.sh clang -integrated-as
  LLVM 0

[1]: https://github.com/ClangBuiltLinux/linux/issues/1320
[2]: https://lore.kernel.org/linux-kbuild/20210307044253.v3h47ucq6ng25iay@archlinux-ax161/

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
2021-04-25 05:14:41 +09:00
Masahiro Yamada
6e0839fda3 kbuild: replace sed with $(subst ) or $(patsubst )
For simple text replacement, it is better to use a built-in function
instead of sed if possible. You can save one process forking.

I do not mean to replace all sed invocations because GNU Make itself
does not support regular expression (unless you use guile).

I just replaced simple ones.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 05:14:01 +09:00
Nathan Chancellor
eec08090bc Makefile: Only specify '--prefix=' when building with clang + GNU as
When building with LLVM_IAS=1, there is no point to specifying
'--prefix=' because that flag is only used to find GNU cross tools,
which will not be used indirectly when using the integrated assembler.
All of the tools are invoked directly from PATH or a full path specified
via the command line, which does not depend on the value of '--prefix='.

Sharing commands to reproduce issues becomes a little bit easier without
a '--prefix=' value because that '--prefix=' value is specific to a
user's machine due to it being an absolute path.

Some further notes from Fangrui Song:

  clang can spawn GNU as (if -f?no-integrated-as is specified) and GNU
  objcopy (-f?no-integrated-as and -gsplit-dwarf and -g[123]).
  objcopy is only used for GNU as assembled object files.
  With integrated assembler, the object file streamer creates .o and
  .dwo simultaneously.
  With GNU as, two objcopy commands are needed to extract .debug*.dwo to
  .dwo files && another command to remove .debug*.dwo sections.

A small consequence of this change (to keep things simple) is that
'--prefix=' will always be specified now, even with a native build, when
it was not before. This should not be an issue due to the way that the
Makefile searches for the prefix (based on elfedit's location). This
ends up improving the experience for host builds because PATH is better
respected and matches GCC's behavior more closely. See the below thread
for more details:

https://lore.kernel.org/r/20210205213651.GA16907@Ryzen-5-4500U.localdomain/

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 05:13:45 +09:00
Nathan Chancellor
c91d4e47e1 Makefile: Remove '--gcc-toolchain' flag
This flag was originally added to allow clang to find the GNU cross
tools in commit 785f11aa59 ("kbuild: Add better clang cross build
support"). This flag was not enough to find the tools at times so
'--prefix' was added to the list in commit ef8c4ed9db ("kbuild: allow
to use GCC toolchain not in Clang search path") and improved upon in
commit ca9b31f6bb ("Makefile: Fix GCC_TOOLCHAIN_DIR prefix for Clang
cross compilation"). Now that '--prefix' specifies a full path and
prefix, '--gcc-toolchain' serves no purpose because the kernel builds
with '-nostdinc' and '-nostdlib'.

This has been verified with self compiled LLVM 10.0.1 and LLVM 13.0.0 as
well as a distribution version of LLVM 11.1.0 without binutils in the
LLVM toolchain locations.

Link: https://reviews.llvm.org/D97902
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Fangrui Song <maskray@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 05:12:55 +09:00
Rasmus Villemoes
0b956e2041 kbuild: apply fixdep logic to link-vmlinux.sh
The patch adding CONFIG_VMLINUX_MAP revealed a small defect in the
build system: link-vmlinux.sh takes decisions based on CONFIG_*
options, but changing one of those does not always lead to vmlinux
being linked again.

For most of the CONFIG_* knobs referenced previously, this has
probably been hidden by those knobs also affecting some object file,
hence indirectly also vmlinux.

But CONFIG_VMLINUX_MAP is only handled inside link-vmlinux.sh, and
changing CONFIG_VMLINUX_MAP=n to CONFIG_VMLINUX_MAP=y does not cause
the build system to re-link (and hence have vmlinux.map
emitted). Since that map file is mostly a debugging aid, this is
merely a nuisance which is easily worked around by just deleting
vmlinux and building again.

But one could imagine other (possibly future) CONFIG options that
actually do affect the vmlinux binary but which are not captured
through some object file dependency.

To fix this, make link-vmlinux.sh emit a .vmlinux.d file in the same
format as the dependency files generated by gcc, and apply the fixdep
logic to that. I've tested that this correctly works with both in-tree
and out-of-tree builds.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 05:12:32 +09:00
Masahiro Yamada
609bbb4de4 kbuild: show warning if 'make headers_check' is used
Since commit 7ecaf069da ("kbuild: move headers_check rule to
usr/include/Makefile"), 'make headers_check' is no-op.

This stub target is remaining here in case some scripts still invoke it.
In order to prompt people to remove stale code, show a noisy warning
message if used. The stub will be really removed after the Linux 5.15
release.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 05:11:54 +09:00
Masahiro Yamada
805b2e1d42 kbuild: include Makefile.compiler only when compiler is needed
Since commit f2f02ebd8f ("kbuild: improve cc-option to clean up all
temporary files"), running 'make kernelversion' in a read-only source
tree emits a bunch of warnings:

  mkdir: cannot create directory '.tmp_12345': Permission denied

No-build targets such as kernelversion, clean, help, etc. do not
need to evaluate $(call cc-option,) or friends. Skip Makefile.compiler
so $(call cc-option,) becomes no-op.

This not only fixes the warnings, but also runs non-build targets much
faster.

Basically, all installation targets should also be non-build targets.
Unfortunately, vdso_install requires the compiler because it builds
vdso before installation. This is a problem that must be fixed by a
separate patch.

Reported-by: Israel Tsadok <itsadok@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 05:09:57 +09:00
Masahiro Yamada
57fd251c78 kbuild: split cc-option and friends to scripts/Makefile.compiler
scripts/Kbuild.include is included everywhere, but macros such as
cc-option are needed by build targets only.

For example, when 'make clean' traverses the tree, it does not need
to evaluate $(call cc-option,).

Split cc-option, ld-option, etc. to scripts/Makefile.compiler, which
is only included from the top Makefile and scripts/Makefile.build.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 05:09:32 +09:00
Linus Torvalds
bf05bf16c7 Linux 5.12-rc8 2021-04-18 14:45:32 -07:00
Masahiro Yamada
f02aa48dde kconfig: use /boot/config-* etc. as DEFCONFIG_LIST only for native build
When the .config file is missing, 'make config', 'make menuconfig', etc.
uses a file listed in DEFCONFIG_LIST, if found, as base configuration.

Ususally, /boot/config-$(uname -r) exists, and is used as default.

However, when you are cross-compiling the kernel, it does not make
sense to use /boot/config-* on the build host. It should default to
arch/$(SRCARCH)/configs/$(KBUILD_DEFCONFIG).

UML previously did not use DEFCONFIG_LIST at all, but it should be
able to use arch/um/configs/$(KBUILD_DEFCONFIG) as a base config file.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-14 15:22:49 +09:00
Masahiro Yamada
dd4659963a kconfig: move default KBUILD_DEFCONFIG back to scripts/kconfig/Makefile
This is a partial revert of commit 2a86f66121 ("kbuild: use
KBUILD_DEFCONFIG as the fallback for DEFCONFIG_LIST").

Now that the reference to $(DEFCONFIG_LIST) was removed from
init/Kconfig, the default KBUILD_DEFCONFIG can go back home.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-14 15:22:49 +09:00
Linus Torvalds
d434405aaa Linux 5.12-rc7 2021-04-11 15:16:13 -07:00
Nayna Jain
b31f2a495d keys: cleanup build time module signing keys
The "mrproper" target is still looking for build time generated keys in
the kernel root directory instead of certs directory. Fix the path and
remove the names of the files which are no longer generated.

Fixes: cfc411e7ff ("Move certificate handling to its own directory")
Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-04-09 10:40:15 -04:00
Sami Tolvanen
cf68fffb66 add support for Clang CFI
This change adds support for Clang’s forward-edge Control Flow
Integrity (CFI) checking. With CONFIG_CFI_CLANG, the compiler
injects a runtime check before each indirect function call to ensure
the target is a valid function with the correct static type. This
restricts possible call targets and makes it more difficult for
an attacker to exploit bugs that allow the modification of stored
function pointers. For more details, see:

  https://clang.llvm.org/docs/ControlFlowIntegrity.html

Clang requires CONFIG_LTO_CLANG to be enabled with CFI to gain
visibility to possible call targets. Kernel modules are supported
with Clang’s cross-DSO CFI mode, which allows checking between
independently compiled components.

With CFI enabled, the compiler injects a __cfi_check() function into
the kernel and each module for validating local call targets. For
cross-module calls that cannot be validated locally, the compiler
calls the global __cfi_slowpath_diag() function, which determines
the target module and calls the correct __cfi_check() function. This
patch includes a slowpath implementation that uses __module_address()
to resolve call targets, and with CONFIG_CFI_CLANG_SHADOW enabled, a
shadow map that speeds up module look-ups by ~3x.

Clang implements indirect call checking using jump tables and
offers two methods of generating them. With canonical jump tables,
the compiler renames each address-taken function to <function>.cfi
and points the original symbol to a jump table entry, which passes
__cfi_check() validation. This isn’t compatible with stand-alone
assembly code, which the compiler doesn’t instrument, and would
result in indirect calls to assembly code to fail. Therefore, we
default to using non-canonical jump tables instead, where the compiler
generates a local jump table entry <function>.cfi_jt for each
address-taken function, and replaces all references to the function
with the address of the jump table entry.

Note that because non-canonical jump table addresses are local
to each component, they break cross-module function address
equality. Specifically, the address of a global function will be
different in each module, as it's replaced with the address of a local
jump table entry. If this address is passed to a different module,
it won’t match the address of the same function taken there. This
may break code that relies on comparing addresses passed from other
components.

CFI checking can be disabled in a function with the __nocfi attribute.
Additionally, CFI can be disabled for an entire compilation unit by
filtering out CC_FLAGS_CFI.

By default, CFI failures result in a kernel panic to stop a potential
exploit. CONFIG_CFI_PERMISSIVE enables a permissive mode, where the
kernel prints out a rate-limited warning instead, and allows execution
to continue. This option is helpful for locating type mismatches, but
should only be enabled during development.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210408182843.1754385-2-samitolvanen@google.com
2021-04-08 16:04:20 -07:00
Kees Cook
39218ff4c6 stack: Optionally randomize kernel stack offset each syscall
This provides the ability for architectures to enable kernel stack base
address offset randomization. This feature is controlled by the boot
param "randomize_kstack_offset=on/off", with its default value set by
CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT.

This feature is based on the original idea from the last public release
of PaX's RANDKSTACK feature: https://pax.grsecurity.net/docs/randkstack.txt
All the credit for the original idea goes to the PaX team. Note that
the design and implementation of this upstream randomize_kstack_offset
feature differs greatly from the RANDKSTACK feature (see below).

Reasoning for the feature:

This feature aims to make harder the various stack-based attacks that
rely on deterministic stack structure. We have had many such attacks in
past (just to name few):

https://jon.oberheide.org/files/infiltrate12-thestackisback.pdf
https://jon.oberheide.org/files/stackjacking-infiltrate11.pdf
https://googleprojectzero.blogspot.com/2016/06/exploiting-recursion-in-linux-kernel_20.html

As Linux kernel stack protections have been constantly improving
(vmap-based stack allocation with guard pages, removal of thread_info,
STACKLEAK), attackers have had to find new ways for their exploits
to work. They have done so, continuing to rely on the kernel's stack
determinism, in situations where VMAP_STACK and THREAD_INFO_IN_TASK_STRUCT
were not relevant. For example, the following recent attacks would have
been hampered if the stack offset was non-deterministic between syscalls:

https://repositorio-aberto.up.pt/bitstream/10216/125357/2/374717.pdf
(page 70: targeting the pt_regs copy with linear stack overflow)

https://a13xp0p0v.github.io/2020/02/15/CVE-2019-18683.html
(leaked stack address from one syscall as a target during next syscall)

The main idea is that since the stack offset is randomized on each system
call, it is harder for an attack to reliably land in any particular place
on the thread stack, even with address exposures, as the stack base will
change on the next syscall. Also, since randomization is performed after
placing pt_regs, the ptrace-based approach[1] to discover the randomized
offset during a long-running syscall should not be possible.

Design description:

During most of the kernel's execution, it runs on the "thread stack",
which is pretty deterministic in its structure: it is fixed in size,
and on every entry from userspace to kernel on a syscall the thread
stack starts construction from an address fetched from the per-cpu
cpu_current_top_of_stack variable. The first element to be pushed to the
thread stack is the pt_regs struct that stores all required CPU registers
and syscall parameters. Finally the specific syscall function is called,
with the stack being used as the kernel executes the resulting request.

The goal of randomize_kstack_offset feature is to add a random offset
after the pt_regs has been pushed to the stack and before the rest of the
thread stack is used during the syscall processing, and to change it every
time a process issues a syscall. The source of randomness is currently
architecture-defined (but x86 is using the low byte of rdtsc()). Future
improvements for different entropy sources is possible, but out of scope
for this patch. Further more, to add more unpredictability, new offsets
are chosen at the end of syscalls (the timing of which should be less
easy to measure from userspace than at syscall entry time), and stored
in a per-CPU variable, so that the life of the value does not stay
explicitly tied to a single task.

As suggested by Andy Lutomirski, the offset is added using alloca()
and an empty asm() statement with an output constraint, since it avoids
changes to assembly syscall entry code, to the unwinder, and provides
correct stack alignment as defined by the compiler.

In order to make this available by default with zero performance impact
for those that don't want it, it is boot-time selectable with static
branches. This way, if the overhead is not wanted, it can just be
left turned off with no performance impact.

The generated assembly for x86_64 with GCC looks like this:

...
ffffffff81003977: 65 8b 05 02 ea 00 7f  mov %gs:0x7f00ea02(%rip),%eax
					    # 12380 <kstack_offset>
ffffffff8100397e: 25 ff 03 00 00        and $0x3ff,%eax
ffffffff81003983: 48 83 c0 0f           add $0xf,%rax
ffffffff81003987: 25 f8 07 00 00        and $0x7f8,%eax
ffffffff8100398c: 48 29 c4              sub %rax,%rsp
ffffffff8100398f: 48 8d 44 24 0f        lea 0xf(%rsp),%rax
ffffffff81003994: 48 83 e0 f0           and $0xfffffffffffffff0,%rax
...

As a result of the above stack alignment, this patch introduces about
5 bits of randomness after pt_regs is spilled to the thread stack on
x86_64, and 6 bits on x86_32 (since its has 1 fewer bit required for
stack alignment). The amount of entropy could be adjusted based on how
much of the stack space we wish to trade for security.

My measure of syscall performance overhead (on x86_64):

lmbench: /usr/lib/lmbench/bin/x86_64-linux-gnu/lat_syscall -N 10000 null
    randomize_kstack_offset=y	Simple syscall: 0.7082 microseconds
    randomize_kstack_offset=n	Simple syscall: 0.7016 microseconds

So, roughly 0.9% overhead growth for a no-op syscall, which is very
manageable. And for people that don't want this, it's off by default.

There are two gotchas with using the alloca() trick. First,
compilers that have Stack Clash protection (-fstack-clash-protection)
enabled by default (e.g. Ubuntu[3]) add pagesize stack probes to
any dynamic stack allocations. While the randomization offset is
always less than a page, the resulting assembly would still contain
(unreachable!) probing routines, bloating the resulting assembly. To
avoid this, -fno-stack-clash-protection is unconditionally added to
the kernel Makefile since this is the only dynamic stack allocation in
the kernel (now that VLAs have been removed) and it is provably safe
from Stack Clash style attacks.

The second gotcha with alloca() is a negative interaction with
-fstack-protector*, in that it sees the alloca() as an array allocation,
which triggers the unconditional addition of the stack canary function
pre/post-amble which slows down syscalls regardless of the static
branch. In order to avoid adding this unneeded check and its associated
performance impact, architectures need to carefully remove uses of
-fstack-protector-strong (or -fstack-protector) in the compilation units
that use the add_random_kstack() macro and to audit the resulting stack
mitigation coverage (to make sure no desired coverage disappears). No
change is visible for this on x86 because the stack protector is already
unconditionally disabled for the compilation unit, but the change is
required on arm64. There is, unfortunately, no attribute that can be
used to disable stack protector for specific functions.

Comparison to PaX RANDKSTACK feature:

The RANDKSTACK feature randomizes the location of the stack start
(cpu_current_top_of_stack), i.e. including the location of pt_regs
structure itself on the stack. Initially this patch followed the same
approach, but during the recent discussions[2], it has been determined
to be of a little value since, if ptrace functionality is available for
an attacker, they can use PTRACE_PEEKUSR/PTRACE_POKEUSR to read/write
different offsets in the pt_regs struct, observe the cache behavior of
the pt_regs accesses, and figure out the random stack offset. Another
difference is that the random offset is stored in a per-cpu variable,
rather than having it be per-thread. As a result, these implementations
differ a fair bit in their implementation details and results, though
obviously the intent is similar.

[1] https://lore.kernel.org/kernel-hardening/2236FBA76BA1254E88B949DDB74E612BA4BC57C1@IRSMSX102.ger.corp.intel.com/
[2] https://lore.kernel.org/kernel-hardening/20190329081358.30497-1-elena.reshetova@intel.com/
[3] https://lists.ubuntu.com/archives/ubuntu-devel/2019-June/040741.html

Co-developed-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210401232347.2791257-4-keescook@chromium.org
2021-04-08 14:05:19 +02:00
Linus Torvalds
e49d033bdd Linux 5.12-rc6 2021-04-04 14:15:36 -07:00
Linus Torvalds
a5e13c6df0 Linux 5.12-rc5 2021-03-28 15:48:16 -07:00
Linus Torvalds
0d02ec6b31 Linux 5.12-rc4 2021-03-21 14:56:43 -07:00
Masahiro Yamada
3204a7fb98 kbuild: prefix $(srctree)/ to some included Makefiles
VPATH is used in Kbuild to make pattern rules search for prerequisites
in both $(objtree) and $(srctree). Some of *.c, *.S files are not real
sources, but generated by tools such as flex, bison, perl.

In contrast, I doubt the benefit of --include-dir=$(abs_srctree) because
it is always clear which Makefiles are real sources, and which are not.

So, my hope is to add $(srctree)/ prefix to all check-in Makefiles,
then remove --include-dir=$(abs_srctree) flag in the future.

I am touching only some Kbuild core parts for now. Treewide fixes will
be needed to achieve this goal.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-03-15 19:20:48 +09:00
Linus Torvalds
1e28eed176 Linux 5.12-rc3 2021-03-14 14:41:02 -07:00
Masahiro Yamada
ce6ed1c4c9 kbuild: rebuild GCC plugins when the compiler is upgraded
Linus reported a build error due to the GCC plugin incompatibility
when the compiler is upgraded. [1]

GCC plugins are tied to a particular GCC version. So, they must be
rebuilt when the compiler is upgraded.

This seems to be a long-standing flaw since the initial support of
GCC plugins.

Extend commit 8b59cd81dc ("kbuild: ensure full rebuild when the
compiler is updated"), so that GCC plugins are covered by the
compiler upgrade detection.

[1]: https://lore.kernel.org/lkml/CAHk-=wieoN5ttOy7SnsGwZv+Fni3R6m-Ut=oxih6bbZ28G+4dw@mail.gmail.com/

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
2021-03-11 14:40:50 +09:00
Masahiro Yamada
993bdde945 kbuild: add image_name to no-sync-config-targets
'make image_name' needs include/config/auto.conf to show the correct
output because KBUILD_IMAGE depends on CONFIG options, but should not
attempt to resync the configuration.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-03-10 04:17:47 +09:00
Linus Torvalds
a38fd87484 Linux 5.12-rc2 2021-03-05 17:33:41 -08:00
Linus Torvalds
fe07bfda2f Linux 5.12-rc1 2021-02-28 16:05:19 -08:00
Masahiro Yamada
207da4c82a kbuild: Fix <linux/version.h> for empty SUBLEVEL or PATCHLEVEL again
Commit 78d3bb4483 ("kbuild: Fix <linux/version.h> for empty SUBLEVEL
or PATCHLEVEL") fixed the build error for empty SUBLEVEL or PATCHLEVEL
by prepending a zero.

Commit 9b82f13e7e ("kbuild: clamp SUBLEVEL to 255") re-introduced
this issue.

This time, we cannot take the same approach because we have C code:

  #define LINUX_VERSION_PATCHLEVEL $(PATCHLEVEL)
  #define LINUX_VERSION_SUBLEVEL $(SUBLEVEL)

Replace empty SUBLEVEL/PATCHLEVEL with a zero.

Fixes: 9b82f13e7e ("kbuild: clamp SUBLEVEL to 255")
Reported-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-and-tested-by: Sasha Levin <sashal@kernel.org>
2021-02-28 15:23:48 +09:00
Masahiro Yamada
2214945422 kbuild: make -s option take precedence over V=1
'make -s' should be really silent. However, 'make -s V=1' prints noisy
log messages from some shell scripts.

Of course, such a combination is odd, but the build system needs to do
the right thing even if a user gives strange input.

If -s is given, KBUILD_VERBOSE should be forced to 0.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-02-28 15:22:02 +09:00
Linus Torvalds
fe1072ff76 clang-lto fixes for v5.12-rc1
- Fix parisc build for ftrace vs mcount (Sami Tolvanen)
 - Move .thinlto-cache remove to "clean" from "distclean" (Masahiro Yamada)
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Merge tag 'clang-lto-v5.12-rc1-fix1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull clang LTO fixes from Kees Cook:
 "This gets parisc building again and moves LTO artifact caching cleanup
  from the 'distclean' build target to 'clean'.

  Summary:

   - Fix parisc build for ftrace vs mcount (Sami Tolvanen)

   - Move .thinlto-cache remove to "clean" from "distclean" (Masahiro Yamada)"

* tag 'clang-lto-v5.12-rc1-fix1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  kbuild: Move .thinlto-cache removal to 'make clean'
  parisc: select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
2021-02-26 10:08:50 -08:00
Masahiro Yamada
4c7858b900 kbuild: Move .thinlto-cache removal to 'make clean'
Instead of 'make distclean', 'make clean' should remove build artifacts
unneeded by external module builds. Obviously, you do not need to keep
this directory.

Fixes: dc5723b02e ("kbuild: add support for Clang LTO")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210225193912.3303604-1-masahiroy@kernel.org
2021-02-25 12:21:06 -08:00
Linus Torvalds
6fbd6cf85a Kbuild updates for v5.12
- Fix false-positive build warnings for ARCH=ia64 builds
 
  - Optimize dictionary size for module compression with xz
 
  - Check the compiler and linker versions in Kconfig
 
  - Fix misuse of extra-y
 
  - Support DWARF v5 debug info
 
  - Clamp SUBLEVEL to 255 because stable releases 4.4.x and 4.9.x
    exceeded the limit
 
  - Add generic syscall{tbl,hdr}.sh for cleanups across arches
 
  - Minor cleanups of genksyms
 
  - Minor cleanups of Kconfig
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Merge tag 'kbuild-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Fix false-positive build warnings for ARCH=ia64 builds

 - Optimize dictionary size for module compression with xz

 - Check the compiler and linker versions in Kconfig

 - Fix misuse of extra-y

 - Support DWARF v5 debug info

 - Clamp SUBLEVEL to 255 because stable releases 4.4.x and 4.9.x
   exceeded the limit

 - Add generic syscall{tbl,hdr}.sh for cleanups across arches

 - Minor cleanups of genksyms

 - Minor cleanups of Kconfig

* tag 'kbuild-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (38 commits)
  initramfs: Remove redundant dependency of RD_ZSTD on BLK_DEV_INITRD
  kbuild: remove deprecated 'always' and 'hostprogs-y/m'
  kbuild: parse C= and M= before changing the working directory
  kbuild: reuse this-makefile to define abs_srctree
  kconfig: unify rule of config, menuconfig, nconfig, gconfig, xconfig
  kconfig: omit --oldaskconfig option for 'make config'
  kconfig: fix 'invalid option' for help option
  kconfig: remove dead code in conf_askvalue()
  kconfig: clean up nested if-conditionals in check_conf()
  kconfig: Remove duplicate call to sym_get_string_value()
  Makefile: Remove # characters from compiler string
  Makefile: reuse CC_VERSION_TEXT
  kbuild: check the minimum linker version in Kconfig
  kbuild: remove ld-version macro
  scripts: add generic syscallhdr.sh
  scripts: add generic syscalltbl.sh
  arch: syscalls: remove $(srctree)/ prefix from syscall tables
  arch: syscalls: add missing FORCE and fix 'targets' to make if_changed work
  gen_compile_commands: prune some directories
  kbuild: simplify access to the kernel's version
  ...
2021-02-25 10:17:31 -08:00
Masahiro Yamada
bcf637f54f kbuild: parse C= and M= before changing the working directory
If Kbuild recurses to the top Makefile (for example, 'make deb-pkg'),
C= and M= are parsed over again, needlessly.

Parse them before changing the working directory. After that,
sub_make_done is set to 1, so they are parsed just once.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-02-24 15:12:06 +09:00
Masahiro Yamada
30cef68d2d kbuild: reuse this-makefile to define abs_srctree
Move this-makefile up, and reuse it to define abs_srctree.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-02-24 15:12:06 +09:00
Nathan Chancellor
c75173a269 Makefile: Remove # characters from compiler string
When using AMD's Optimizing C/C++ Compiler (AOCC), the build fails due
to a # character in the version string, which is interpreted as a
comment:

$ make CC=clang defconfig init/main.o
include/config/auto.conf.cmd:1374: *** invalid syntax in conditional. Stop.

$ sed -n 1374p include/config/auto.conf.cmd
ifneq "$(CC_VERSION_TEXT)" "AMD clang version 11.0.0 (CLANG: AOCC_2.3.0-Build#85 2020_11_10) (based on LLVM Mirror.Version.11.0.0)"

Remove all # characters in the version string so that the build does not
fail unexpectedly.

Link: https://github.com/ClangBuiltLinux/linux/issues/1298
Reported-by: Michael Fuckner <michael@fuckner.net>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-02-24 15:12:06 +09:00
Nick Desaulniers
db07562aea Makefile: reuse CC_VERSION_TEXT
I noticed we're invoking $(CC) via $(shell) more than once to check the
version.  Let's reuse the first string captured in $CC_VERSION_TEXT.

Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
[masahiro.yamada:
CC_VERSION_TEXT is assigned by = instead of :=, so this $(shell ) is
evaluated multiple times anyway. The number of $(CC) invocations will
be still the same. Replacing 'grep' with the built-in $(findstring )
will give real performance benefit.]
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-02-24 15:11:17 +09:00
Linus Torvalds
414eece95b clang-lto for v5.12-rc1 (part2)
- Generate __mcount_loc in objtool (Peter Zijlstra)
 - Support running objtool against vmlinux.o (Sami Tolvanen)
 - Clang LTO enablement for x86 (Sami Tolvanen)
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Merge tag 'clang-lto-v5.12-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull more clang LTO updates from Kees Cook:
 "Clang LTO x86 enablement.

  Full disclosure: while this has _not_ been in linux-next (since it
  initially looked like the objtool dependencies weren't going to make
  v5.12), it has been under daily build and runtime testing by Sami for
  quite some time. These x86 portions have been discussed on lkml, with
  Peter, Josh, and others helping nail things down.

  The bulk of the changes are to get objtool working happily. The rest
  of the x86 enablement is very small.

  Summary:

   - Generate __mcount_loc in objtool (Peter Zijlstra)

   - Support running objtool against vmlinux.o (Sami Tolvanen)

   - Clang LTO enablement for x86 (Sami Tolvanen)"

Link: https://lore.kernel.org/lkml/20201013003203.4168817-26-samitolvanen@google.com/
Link: https://lore.kernel.org/lkml/cover.1611263461.git.jpoimboe@redhat.com/

* tag 'clang-lto-v5.12-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  kbuild: lto: force rebuilds when switching CONFIG_LTO
  x86, build: allow LTO to be selected
  x86, cpu: disable LTO for cpu.c
  x86, vdso: disable LTO only for vDSO
  kbuild: lto: postpone objtool
  objtool: Split noinstr validation from --vmlinux
  x86, build: use objtool mcount
  tracing: add support for objtool mcount
  objtool: Don't autodetect vmlinux.o
  objtool: Fix __mcount_loc generation with Clang's assembler
  objtool: Add a pass for generating __mcount_loc
2021-02-23 15:13:45 -08:00
Sami Tolvanen
5e95325fbb kbuild: lto: force rebuilds when switching CONFIG_LTO
When doing non-clean builds and switching between CONFIG_LTO=n and
CONFIG_LTO=y, the build system (correctly) didn't notice that assembly
and LTO-excluded C object files were rewritten in place by objtool (to
add the .orc_unwind* sections), since their build command lines were the
same between CONFIG_LTO=y and CONFIG_LTO=n. The objtool step would fail:

vmlinux.o: warning: objtool: file already has .orc_unwind section, skipping
make: *** [Makefile:1194: vmlinux] Error 255

Avoid this by making sure the build will see a difference between an LTO
and non-LTO build (by including "-fno-lto" in KBUILD_*FLAGS). This will
get ignored when CC_FLAGS_LTO is present, and will not be included at
all when CONFIG_LTO=n.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
2021-02-23 14:10:44 -08:00
Sami Tolvanen
22c8542d7b tracing: add support for objtool mcount
This change adds build support for using objtool to generate
__mcount_loc sections.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
2021-02-23 12:46:57 -08:00
Linus Torvalds
79db4d2293 clang-lto series for v5.12-rc1
- Clang LTO build infrastructure and arm64-specific enablement (Sami Tolvanen)
 - Recursive build CC_FLAGS_LTO fix (Alexander Lobakin)
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Merge tag 'clang-lto-v5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull clang LTO updates from Kees Cook:
 "Clang Link Time Optimization.

  This is built on the work done preparing for LTO by arm64 folks,
  tracing folks, etc. This includes the core changes as well as the
  remaining pieces for arm64 (LTO has been the default build method on
  Android for about 3 years now, as it is the prerequisite for the
  Control Flow Integrity protections).

  While x86 LTO enablement is done, it depends on some pending objtool
  clean-ups. It's possible that I'll send a "part 2" pull request for
  LTO that includes x86 support.

  For merge log posterity, and as detailed in commit dc5723b02e
  ("kbuild: add support for Clang LTO"), here is the lt;dr to do an LTO
  build:

        make LLVM=1 LLVM_IAS=1 defconfig
        scripts/config -e LTO_CLANG_THIN
        make LLVM=1 LLVM_IAS=1

  (To do a cross-compile of arm64, add "CROSS_COMPILE=aarch64-linux-gnu-"
  and "ARCH=arm64" to the "make" command lines.)

  Summary:

   - Clang LTO build infrastructure and arm64-specific enablement (Sami
     Tolvanen)

   - Recursive build CC_FLAGS_LTO fix (Alexander Lobakin)"

* tag 'clang-lto-v5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  kbuild: prevent CC_FLAGS_LTO self-bloating on recursive rebuilds
  arm64: allow LTO to be selected
  arm64: disable recordmcount with DYNAMIC_FTRACE_WITH_REGS
  arm64: vdso: disable LTO
  drivers/misc/lkdtm: disable LTO for rodata.o
  efi/libstub: disable LTO
  scripts/mod: disable LTO for empty.c
  modpost: lto: strip .lto from module names
  PCI: Fix PREL32 relocations for LTO
  init: lto: fix PREL32 relocations
  init: lto: ensure initcall ordering
  kbuild: lto: add a default list of used symbols
  kbuild: lto: merge module sections
  kbuild: lto: limit inlining
  kbuild: lto: fix module versioning
  kbuild: add support for Clang LTO
  tracing: move function tracer options to Kconfig
2021-02-23 09:28:51 -08:00
Linus Torvalds
a99163e9e7 Devicetree updates for v5.12:
- Sync dtc to upstream version v1.6.0-51-g183df9e9c2b9 and build
   host fdtoverlay
 
 - Add kbuild support to build DT overlays (%.dtbo)
 
 - Drop NULLifying match table in of_match_device(). In preparation for
   this, there are several driver cleanups to use
   (of_)?device_get_match_data().
 
 - Drop pointless wrappers from DT struct device API
 
 - Convert USB binding schemas to use graph schema and remove old plain
   text graph binding doc
 
 - Convert spi-nor and v3d GPU bindings to DT schema
 
 - Tree wide schema fixes for if/then schemas, array size constraints,
   and undocumented compatible strings in examples
 
 - Handle 'no-map' correctly for already reserved memblock regions
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Merge tag 'devicetree-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux

Pull devicetree updates from Rob Herring:

 - Sync dtc to upstream version v1.6.0-51-g183df9e9c2b9 and build host
   fdtoverlay

 - Add kbuild support to build DT overlays (%.dtbo)

 - Drop NULLifying match table in of_match_device().

   In preparation for this, there are several driver cleanups to use
   (of_)?device_get_match_data().

 - Drop pointless wrappers from DT struct device API

 - Convert USB binding schemas to use graph schema and remove old plain
   text graph binding doc

 - Convert spi-nor and v3d GPU bindings to DT schema

 - Tree wide schema fixes for if/then schemas, array size constraints,
   and undocumented compatible strings in examples

 - Handle 'no-map' correctly for already reserved memblock regions

* tag 'devicetree-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (35 commits)
  driver core: platform: Drop of_device_node_put() wrapper
  of: Remove of_dev_{get,put}()
  dt-bindings: usb: Change descibe to describe in usbmisc-imx.txt
  dt-bindings: can: rcar_canfd: Group tuples in pin control properties
  dt-bindings: power: renesas,apmu: Group tuples in cpus properties
  dt-bindings: mtd: spi-nor: Convert to DT schema format
  dt-bindings: Use portable sort for version cmp
  dt-bindings: ethernet-controller: fix fixed-link specification
  dt-bindings: irqchip: Add node name to PRUSS INTC
  dt-bindings: interconnect: Fix the expected number of cells
  dt-bindings: Fix errors in 'if' schemas
  dt-bindings: iommu: renesas,ipmmu-vmsa: Make 'power-domains' conditionally required
  dt-bindings: Fix undocumented compatible strings in examples
  kbuild: Add support to build overlays (%.dtbo)
  scripts: dtc: Remove the unused fdtdump.c file
  scripts: dtc: Build fdtoverlay tool
  scripts/dtc: Update to upstream version v1.6.0-51-g183df9e9c2b9
  scripts: dtc: Fetch fdtoverlay.c from external DTC project
  dt-bindings: thermal: sun8i: Fix misplaced schema keyword in compatible strings
  dt-bindings: iio: dac: Fix AD5686 references
  ...
2021-02-22 10:05:12 -08:00
Linus Torvalds
51e6d17809 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking updates from David Miller:
 "Here is what we have this merge window:

   1) Support SW steering for mlx5 Connect-X6Dx, from Yevgeny Kliteynik.

   2) Add RSS multi group support to octeontx2-pf driver, from Geetha
      Sowjanya.

   3) Add support for KS8851 PHY. From Marek Vasut.

   4) Add support for GarfieldPeak bluetooth controller from Kiran K.

   5) Add support for half-duplex tcan4x5x can controllers.

   6) Add batch skb rx processing to bcrm63xx_enet, from Sieng Piaw
      Liew.

   7) Rework RX port offload infrastructure, particularly wrt, UDP
      tunneling, from Jakub Kicinski.

   8) Add BCM72116 PHY support, from Florian Fainelli.

   9) Remove Dsa specific notifiers, they are unnecessary. From Vladimir
      Oltean.

  10) Add support for picosecond rx delay in dwmac-meson8b chips. From
      Martin Blumenstingl.

  11) Support TSO on xfrm interfaces from Eyal Birger.

  12) Add support for MP_PRIO to mptcp stack, from Geliang Tang.

  13) Support BCM4908 integrated switch, from Rafał Miłecki.

  14) Support for directly accessing kernel module variables via module
      BTF info, from Andrii Naryiko.

  15) Add DASH (esktop and mobile Architecture for System Hardware)
      support to r8169 driver, from Heiner Kallweit.

  16) Add rx vlan filtering to dpaa2-eth, from Ionut-robert Aron.

  17) Add support for 100 base0x SFP devices, from Bjarni Jonasson.

  18) Support link aggregation in DSA, from Tobias Waldekranz.

  19) Support for bitwidse atomics in bpf, from Brendan Jackman.

  20) SmartEEE support in at803x driver, from Russell King.

  21) Add support for flow based tunneling to GTP, from Pravin B Shelar.

  22) Allow arbitrary number of interconnrcts in ipa, from Alex Elder.

  23) TLS RX offload for bonding, from Tariq Toukan.

  24) RX decap offklload support in mac80211, from Felix Fietkou.

  25) devlink health saupport in octeontx2-af, from George Cherian.

  26) Add TTL attr to SCM_TIMESTAMP_OPT_STATS, from Yousuk Seung

  27) Delegated actionss support in mptcp, from Paolo Abeni.

  28) Support receive timestamping when doin zerocopy tcp receive. From
      Arjun Ray.

  29) HTB offload support for mlx5, from Maxim Mikityanskiy.

  30) UDP GRO forwarding, from Maxim Mikityanskiy.

  31) TAPRIO offloading in dsa hellcreek driver, from Kurt Kanzenbach.

  32) Weighted random twos choice algorithm for ipvs, from Darby Payne.

  33) Fix netdev registration deadlock, from Johannes Berg.

  34) Various conversions to new tasklet api, from EmilRenner Berthing.

  35) Bulk skb allocations in veth, from Lorenzo Bianconi.

  36) New ethtool interface for lane setting, from Danielle Ratson.

  37) Offload failiure notifications for routes, from Amit Cohen.

  38) BCM4908 support, from Rafał Miłecki.

  39) Support several new iwlwifi chips, from Ihab Zhaika.

  40) Flow drector support for ipv6 in i40e, from Przemyslaw Patynowski.

  41) Support for mhi prrotocols, from Loic Poulain.

  42) Optimize bpf program stats.

  43) Implement RFC6056, for better port randomization, from Eric
      Dumazet.

  44) hsr tag offloading support from George McCollister.

  45) Netpoll support in qede, from Bhaskar Upadhaya.

  46) 2005/400g speed support in bonding 3ad mode, from Nikolay
      Aleksandrov.

  47) Netlink event support in mptcp, from Florian Westphal.

  48) Better skbuff caching, from Alexander Lobakin.

  49) MRP (Media Redundancy Protocol) offloading in DSA and a few
      drivers, from Horatiu Vultur.

  50) mqprio saupport in mvneta, from Maxime Chevallier.

  51) Remove of_phy_attach, no longer needed, from Florian Fainelli"

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1766 commits)
  octeontx2-pf: Fix otx2_get_fecparam()
  cteontx2-pf: cn10k: Prevent harmless double shift bugs
  net: stmmac: Add PCI bus info to ethtool driver query output
  ptp: ptp_clockmatrix: clean-up - parenthesis around a == b are unnecessary
  ptp: ptp_clockmatrix: Simplify code - remove unnecessary `err` variable.
  ptp: ptp_clockmatrix: Coding style - tighten vertical spacing.
  ptp: ptp_clockmatrix: Clean-up dev_*() messages.
  ptp: ptp_clockmatrix: Remove unused header declarations.
  ptp: ptp_clockmatrix: Add alignment of 1 PPS to idtcm_perout_enable.
  ptp: ptp_clockmatrix: Add wait_for_sys_apll_dpll_lock.
  net: stmmac: dwmac-sun8i: Add a shutdown callback
  net: stmmac: dwmac-sun8i: Minor probe function cleanup
  net: stmmac: dwmac-sun8i: Use reset_control_reset
  net: stmmac: dwmac-sun8i: Remove unnecessary PHY power check
  net: stmmac: dwmac-sun8i: Return void from PHY unpower
  r8169: use macro pm_ptr
  net: mdio: Remove of_phy_attach()
  net: mscc: ocelot: select PACKING in the Kconfig
  net: re-solve some conflicts after net -> net-next merge
  net: dsa: tag_rtl4_a: Support also egress tags
  ...
2021-02-20 17:45:32 -08:00
Alexander Lobakin
2b86895205 kbuild: prevent CC_FLAGS_LTO self-bloating on recursive rebuilds
CC_FLAGS_LTO gets initialized only via +=, never with := or =.
When building with CONFIG_TRIM_UNUSED_KSYMS, Kbuild may perform
several kernel rebuilds to satisfy symbol dependencies. In this
case, value of CC_FLAGS_LTO is concatenated each time, which
triggers a full rebuild.
Initialize it with := to fix this.

Fixes: dc5723b02e ("kbuild: add support for Clang LTO")
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210121184544.659998-1-alobakin@pm.me
2021-02-17 10:10:37 -08:00
David S. Miller
b8af417e4d Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:

====================
pull-request: bpf-next 2021-02-16

The following pull-request contains BPF updates for your *net-next* tree.

There's a small merge conflict between 7eeba1706e ("tcp: Add receive timestamp
support for receive zerocopy.") from net-next tree and 9cacf81f81 ("bpf: Remove
extra lock_sock for TCP_ZEROCOPY_RECEIVE") from bpf-next tree. Resolve as follows:

  [...]
                lock_sock(sk);
                err = tcp_zerocopy_receive(sk, &zc, &tss);
                err = BPF_CGROUP_RUN_PROG_GETSOCKOPT_KERN(sk, level, optname,
                                                          &zc, &len, err);
                release_sock(sk);
  [...]

We've added 116 non-merge commits during the last 27 day(s) which contain
a total of 156 files changed, 5662 insertions(+), 1489 deletions(-).

The main changes are:

1) Adds support of pointers to types with known size among global function
   args to overcome the limit on max # of allowed args, from Dmitrii Banshchikov.

2) Add bpf_iter for task_vma which can be used to generate information similar
   to /proc/pid/maps, from Song Liu.

3) Enable bpf_{g,s}etsockopt() from all sock_addr related program hooks. Allow
   rewriting bind user ports from BPF side below the ip_unprivileged_port_start
   range, both from Stanislav Fomichev.

4) Prevent recursion on fentry/fexit & sleepable programs and allow map-in-map
   as well as per-cpu maps for the latter, from Alexei Starovoitov.

5) Add selftest script to run BPF CI locally. Also enable BPF ringbuffer
   for sleepable programs, both from KP Singh.

6) Extend verifier to enable variable offset read/write access to the BPF
   program stack, from Andrei Matei.

7) Improve tc & XDP MTU handling and add a new bpf_check_mtu() helper to
   query device MTU from programs, from Jesper Dangaard Brouer.

8) Allow bpf_get_socket_cookie() helper also be called from [sleepable] BPF
   tracing programs, from Florent Revest.

9) Extend x86 JIT to pad JMPs with NOPs for helping image to converge when
   otherwise too many passes are required, from Gary Lin.

10) Verifier fixes on atomics with BPF_FETCH as well as function-by-function
    verification both related to zero-extension handling, from Ilya Leoshkevich.

11) Better kernel build integration of resolve_btfids tool, from Jiri Olsa.

12) Batch of AF_XDP selftest cleanups and small performance improvement
    for libbpf's xsk map redirect for newer kernels, from Björn Töpel.

13) Follow-up BPF doc and verifier improvements around atomics with
    BPF_FETCH, from Brendan Jackman.

14) Permit zero-sized data sections e.g. if ELF .rodata section contains
    read-only data from local variables, from Yonghong Song.

15) veth driver skb bulk-allocation for ndo_xdp_xmit, from Lorenzo Bianconi.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2021-02-16 13:14:06 -08:00
Sasha Levin
88a686728b kbuild: simplify access to the kernel's version
Instead of storing the version in a single integer and having various
kernel (and userspace) code how it's constructed, export individual
(major, patchlevel, sublevel) components and simplify kernel code that
uses it.

This should also make it easier on userspace.

Signed-off-by: Sasha Levin <sashal@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-02-16 12:01:45 +09:00
Sasha Levin
9b82f13e7e kbuild: clamp SUBLEVEL to 255
Right now if SUBLEVEL becomes larger than 255 it will overflow into the
territory of PATCHLEVEL, causing havoc in userspace that tests for
specific kernel version.

While userspace code tests for MAJOR and PATCHLEVEL, it doesn't test
SUBLEVEL at any point as ABI changes don't happen in the context of
stable tree.

Thus, to avoid overflows, simply clamp SUBLEVEL to it's maximum value in
the context of LINUX_VERSION_CODE. This does not affect "make
kernelversion" and such.

Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-02-16 12:01:45 +09:00
Nick Desaulniers
98cd6f521f Kconfig: allow explicit opt in to DWARF v5
DWARF v5 is the latest standard of the DWARF debug info format. GCC 11
will change the implicit default DWARF version, if left unspecified, to
DWARF v5.

Allow users of Clang and older versions of GCC that have not changed the
implicit default DWARF version to DWARF v5 to opt in. This can help
testing consumers of DWARF debug info in preparation of v5 becoming more
widespread, as well as result in significant binary size savings of the
pre-stripped vmlinux image.

DWARF5 wins significantly in terms of size when mixed with compression
(CONFIG_DEBUG_INFO_COMPRESSED).

363M    vmlinux.clang12.dwarf5.compressed
434M    vmlinux.clang12.dwarf4.compressed
439M    vmlinux.clang12.dwarf2.compressed
457M    vmlinux.clang12.dwarf5
536M    vmlinux.clang12.dwarf4
548M    vmlinux.clang12.dwarf2

515M    vmlinux.gcc10.2.dwarf5.compressed
599M    vmlinux.gcc10.2.dwarf4.compressed
624M    vmlinux.gcc10.2.dwarf2.compressed
630M    vmlinux.gcc10.2.dwarf5
765M    vmlinux.gcc10.2.dwarf4
809M    vmlinux.gcc10.2.dwarf2

Though the quality of debug info is harder to quantify; size is not a
proxy for quality.

Jakub notes:
  One thing is GCC DWARF-5 support, that is whether the compiler will
  support -gdwarf-5 flag, and that support should be there from GCC 7
  onwards.

  All [GCC] 5.1 - 6.x did was start accepting -gdwarf-5 as experimental
  option that enabled some small DWARF subset (initially only a few
  DW_LANG_* codes newly added to DWARF5 drafts).  Only GCC 7 (released
  after DWARF 5 has been finalized) started emitting DWARF5 section
  headers and got most of the DWARF5 changes in...

  Another separate thing is whether the assembler does support
  the -gdwarf-5 option (i.e. if you can compile assembler files
  with -Wa,-gdwarf-5) ... That option is about whether the assembler
  will emit DWARF5 or DWARF2 .debug_line.  It is fine to compile C sources
  with -gdwarf-5 and use DWARF2 .debug_line for assembler files if as
  doesn't support it.

Version check GCC so that we don't need to worry about the difference in
command line args between GNU readelf and llvm-readelf/llvm-dwarfdump to
validate the DWARF Version in the assembler feature detection script.

Most issues with clang produced assembler were fixed in binutils 2.35.1,
but 2.35.2 fixed issues related to requiring the flag -Wa,-gdwarf-5
explicitly. The added shell script test checks for the latter, and is
only required when using clang without its integrated assembler, though
we use for clang regardless as we do not yet have a way to query the
assembler from Kconfig.

Disabled for now if CONFIG_DEBUG_INFO_BTF is set; pahole doesn't yet
recognize the new additions to the DWARF debug info.

This only modifies the DWARF version emitted by the compiler, not the
assembler.

The DWARF version of a binary can be validated with:
$ llvm-dwarfdump <object file> | head -n 4 | grep version
or
$ readelf --debug-dump=info <object file> 2>/dev/null | grep Version

Parts of the tree don't reuse DEBUG_CFLAGS as they should; such cleanup
is left as a follow up.

Link: http://www.dwarfstd.org/doc/DWARF5.pdf
Link: https://bugzilla.redhat.com/show_bug.cgi?id=1922707
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Suggested-by: Arvind Sankar <nivedita@alum.mit.edu>
Suggested-by: Caroline Tice <cmtice@google.com>
Suggested-by: Fangrui Song <maskray@google.com>
Suggested-by: Jakub Jelinek <jakub@redhat.com>
Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Suggested-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM/Clang v12.0.0-rc1 x86-64
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-02-16 12:01:45 +09:00
Nick Desaulniers
a66049e2cf Kbuild: make DWARF version a choice
Adds a default CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT which allows
the implicit default version of DWARF emitted by the toolchain to
progress over time.

Modifies CONFIG_DEBUG_INFO_DWARF4 to be a member of a choice, making it
mutually exclusive with CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT. Users
may want to select this if they are using a newer toolchain, but have
consumers of the DWARF debug info that aren't yet ready for newer DWARF
versions' debug info.

Does so in a way that's forward compatible with existing
configs, and makes adding future versions more straightforward. This
patch does not change the current behavior or selection of DWARF
version for users upgrading to kernels with this patch.

GCC since ~4.8 has defaulted to DWARF v4 implicitly, and GCC 11 has
bumped this to v5.

Remove the Kconfig help text  about DWARF v4 being larger.  It's
empirically false for the latest toolchains for x86_64 defconfig, has no
point of reference (I suspect it was DWARF v2 but that's stil
empirically false), and debug info size is not a qualatative measure.

Suggested-by: Arvind Sankar <nivedita@alum.mit.edu>
Suggested-by: Fangrui Song <maskray@google.com>
Suggested-by: Jakub Jelinek <jakub@redhat.com>
Suggested-by: Mark Wielaard <mark@klomp.org>
Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-02-16 12:01:45 +09:00
Masahiro Yamada
0dd77e957a kbuild: stop removing stale <linux/version.h> file
Revert commit 223c24a7db ("kbuild: Automatically remove stale
<linux/version.h> file").

It was more than 6 years ago. I do not expect anybody to start
git-bisect for such a big window.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-02-16 12:01:45 +09:00
Linus Torvalds
f40ddce885 Linux 5.11 2021-02-14 14:32:24 -08:00
Tor Vic
db4632c65e Makefile: use smaller dictionary size for xz module compression
By default, xz without parameters uses a dictionary size of 8 MB.
However, most modules are much smaller than that.
The xz manpage states that 'increasing dictionary size usually improves
compression ratio, but a dictionary bigger than the uncompressed file
is waste of memory'.
Use a dictionary size of 2 MB for module compression, resulting in
slightly higher compression speed while still maintaining a good
compression ratio.

Signed-off-by: Tor Vic <torvic9@mailbox.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-02-12 05:11:19 +09:00
Jiri Olsa
0e1aa629f1 kbuild: Do not clean resolve_btfids if the output does not exist
Nathan reported issue with cleaning empty build directory:

  $ make -s O=build distclean
  ../../scripts/Makefile.include:4: *** \
  O=/ho...build/tools/bpf/resolve_btfids does not exist.  Stop.

The problem that tools scripts require existing output
directory, otherwise it fails.

Adding check around the resolve_btfids clean target to
ensure the output directory is in place.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/bpf/20210211124004.1144344-1-jolsa@kernel.org
2021-02-11 11:27:58 -08:00
David S. Miller
dc9d87581d Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-02-10 13:30:12 -08:00
Jiri Olsa
50d3a3f816 kbuild: Add resolve_btfids clean to root clean target
The resolve_btfids tool is used during the kernel build,
so we should clean it on kernel's make clean.

Invoking the the resolve_btfids clean as part of root
'make clean'.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20210205124020.683286-5-jolsa@kernel.org
2021-02-08 21:21:39 -08:00
Linus Torvalds
92bf22614b Linux 5.11-rc7 2021-02-07 13:57:38 -08:00
Linus Torvalds
e24f9c5f6e - Remove superfluous EFI PGD range checks which lead to those assertions failing
with certain kernel configs and LLVM.
 
 - Disable setting breakpoints on facilities involved in #DB exception handling
 to avoid infinite loops.
 
 - Add extra serialization to non-serializing MSRs (IA32_TSC_DEADLINE and
 x2 APIC MSRs) to adhere to SDM's recommendation and avoid any theoretical
 issues.
 
 - Re-add the EPB MSR reading on turbostat so that it works on older
 kernels which don't have the corresponding EPB sysfs file.
 
 - Add Alder Lake to the list of CPUs which support split lock.
 
 - Fix %dr6 register handling in order to be able to set watchpoints with gdb
 again.
 
 - Disable CET instrumentation in the kernel so that gcc doesn't add
 ENDBR64 to kernel code and thus confuse tracing.
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Merge tag 'x86_urgent_for_v5.11_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Borislav Petkov:
 "I hope this is the last batch of x86/urgent updates for this round:

   - Remove superfluous EFI PGD range checks which lead to those
     assertions failing with certain kernel configs and LLVM.

   - Disable setting breakpoints on facilities involved in #DB exception
     handling to avoid infinite loops.

   - Add extra serialization to non-serializing MSRs (IA32_TSC_DEADLINE
     and x2 APIC MSRs) to adhere to SDM's recommendation and avoid any
     theoretical issues.

   - Re-add the EPB MSR reading on turbostat so that it works on older
     kernels which don't have the corresponding EPB sysfs file.

   - Add Alder Lake to the list of CPUs which support split lock.

   - Fix %dr6 register handling in order to be able to set watchpoints
     with gdb again.

   - Disable CET instrumentation in the kernel so that gcc doesn't add
     ENDBR64 to kernel code and thus confuse tracing"

* tag 'x86_urgent_for_v5.11_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/efi: Remove EFI PGD build time checks
  x86/debug: Prevent data breakpoints on cpu_dr7
  x86/debug: Prevent data breakpoints on __per_cpu_offset
  x86/apic: Add extra serialization for non-serializing MSRs
  tools/power/turbostat: Fallback to an MSR read for EPB
  x86/split_lock: Enable the split lock feature on another Alder Lake CPU
  x86/debug: Fix DR6 handling
  x86/build: Disable CET instrumentation in the kernel
2021-02-07 09:40:47 -08:00
Linus Torvalds
2db138bb9f Kbuild fixes for v5.11 (2nd)
- Use the 'python3' command to invoke python scripts because some
    distributions do not provide the 'python' command any more.
 
  - Clean-up and update documents
 
  - Use pkg-config to search libcrypto
 
  - Fix duplicated debug flags
 
  - Ignore some more stubs in scripts/kallsyms.c
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Merge tag 'kbuild-fixes-v5.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - Use the 'python3' command to invoke python scripts because some
   distributions do not provide the 'python' command any more.

 - Clean-up and update documents

 - Use pkg-config to search libcrypto

 - Fix duplicated debug flags

 - Ignore some more stubs in scripts/kallsyms.c

* tag 'kbuild-fixes-v5.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kallsyms: fix nonconverging kallsyms table with lld
  kbuild: fix duplicated flags in DEBUG_CFLAGS
  scripts/clang-tools: switch explicitly to Python 3
  kbuild: remove PYTHON variable
  Documentation/llvm: Add a section about supported architectures
  Revert "checkpatch: add check for keyword 'boolean' in Kconfig definitions"
  scripts: use pkg-config to locate libcrypto
  kconfig: mconf: fix HOSTCC call
  doc: gcc-plugins: update gcc-plugins.rst
  kbuild: simplify GCC_PLUGINS enablement in dummy-tools/gcc
  Documentation/Kbuild: Remove references to gcc-plugin.sh
  scripts: switch explicitly to Python 3
2021-02-07 09:37:37 -08:00
Masahiro Yamada
315da87c0f kbuild: fix duplicated flags in DEBUG_CFLAGS
Sedat Dilek noticed duplicated flags in DEBUG_CFLAGS when building
deb-pkg with CONFIG_DEBUG_INFO. For example, 'make CC=clang bindeb-pkg'
reproduces the issue.

Kbuild recurses to the top Makefile for some targets such as package
builds.

With commit 121c5d08d5 ("kbuild: Only add -fno-var-tracking-assignments
for old GCC versions") applied, DEBUG_CFLAGS is now reset only when
CONFIG_CC_IS_GCC=y.

Fix it to reset DEBUG_CFLAGS all the time.

Fixes: 121c5d08d5 ("kbuild: Only add -fno-var-tracking-assignments for old GCC versions")
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Mark Wielaard <mark@klomp.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
2021-02-05 17:53:28 +09:00
Viresh Kumar
ce88c9c794 kbuild: Add support to build overlays (%.dtbo)
Add support for building DT overlays (%.dtbo). The overlay's source file
will have the usual extension, i.e. .dts, though the blob will have
.dtbo extension to distinguish it from normal blobs.

Acked-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/434ba2467dd0cd011565625aeb3450650afe0aae.1611904394.git.viresh.kumar@linaro.org
2021-02-04 09:00:04 -06:00
Jakub Kicinski
d1e1355aef Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-02-02 14:21:31 -08:00
Masahiro Yamada
d8d2d38275 kbuild: remove PYTHON variable
Python retired in 2020, and some distributions do not provide the
'python' command any more.

As in commit 51839e29cb ("scripts: switch explicitly to Python 3"),
we need to use more specific 'python3' to invoke scripts even if they
are written in a way compatible with both Python 2 and 3.

This commit removes the variable 'PYTHON', and switches the existing
users to 'PYTHON3'.

BTW, PEP 394 (https://www.python.org/dev/peps/pep-0394/) is a helpful
material.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-02-01 10:37:19 +09:00
Linus Torvalds
1048ba83fb Linux 5.11-rc6 2021-01-31 13:50:09 -08:00
Josh Poimboeuf
20bf2b3787 x86/build: Disable CET instrumentation in the kernel
With retpolines disabled, some configurations of GCC, and specifically
the GCC versions 9 and 10 in Ubuntu will add Intel CET instrumentation
to the kernel by default. That breaks certain tracing scenarios by
adding a superfluous ENDBR64 instruction before the fentry call, for
functions which can be called indirectly.

CET instrumentation isn't currently necessary in the kernel, as CET is
only supported in user space. Disable it unconditionally and move it
into the x86's Makefile as CET/CFI... enablement should be a per-arch
decision anyway.

 [ bp: Massage and extend commit message. ]

Fixes: 29be86d7f9 ("kbuild: add -fcf-protection=none when using retpoline flags")
Reported-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Cc: <stable@vger.kernel.org>
Cc: Seth Forshee <seth.forshee@canonical.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Link: https://lkml.kernel.org/r/20210128215219.6kct3h2eiustncws@treble
2021-01-29 18:41:06 +01:00
Jakub Kicinski
c358f95205 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
drivers/net/can/dev.c
  b552766c87 ("can: dev: prevent potential information leak in can_fill_info()")
  3e77f70e73 ("can: dev: move driver related infrastructure into separate subdir")
  0a042c6ec9 ("can: dev: move netlink related code into seperate file")

  Code move.

drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
  57ac4a31c4 ("net/mlx5e: Correctly handle changing the number of queues when the interface is down")
  214baf2287 ("net/mlx5e: Support HTB offload")

  Adjacent code changes

net/switchdev/switchdev.c
  20776b465c ("net: switchdev: don't set port_obj_info->handled true when -EOPNOTSUPP")
  ffb68fc58e ("net: switchdev: remove the transaction structure from port object notifiers")
  bae33f2b5a ("net: switchdev: remove the transaction structure from port attributes")

  Transaction parameter gets dropped otherwise keep the fix.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-01-28 17:09:31 -08:00
Masahiro Yamada
8b5f4eb3ab net: move CONFIG_NET guard to top Makefile
When CONFIG_NET is disabled, nothing under the net/ directory is
compiled. Move the CONFIG_NET guard to the top Makefile so the net/
directory is entirely skipped.

When Kbuild visits net/Makefile, CONFIG_NET is obvioulsy 'y' because
CONFIG_NET is a bool option. Clean up net/Makefile.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20210125231659.106201-1-masahiroy@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-01-27 17:03:52 -08:00
Linus Torvalds
6ee1d745b7 Linux 5.11-rc5 2021-01-24 16:47:14 -08:00
Linus Torvalds
19c329f680 Linux 5.11-rc4 2021-01-17 16:37:05 -08:00
Sami Tolvanen
22d429e75f kbuild: lto: limit inlining
This change limits function inlining across translation unit boundaries
in order to reduce the binary size with LTO. The -import-instr-limit
flag defines a size limit, as the number of LLVM IR instructions, for
importing functions from other TUs, defaulting to 100.

Based on testing with arm64 defconfig, we found that a limit of 5 is a
reasonable compromise between performance and binary size, reducing the
size of a stripped vmlinux by 11%.

Suggested-by: George Burgess IV <gbiv@google.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-5-samitolvanen@google.com
2021-01-14 08:21:08 -08:00
Sami Tolvanen
38e8918490 kbuild: lto: fix module versioning
With CONFIG_MODVERSIONS, version information is linked into each
compilation unit that exports symbols. With LTO, we cannot use this
method as all C code is compiled into LLVM bitcode instead. This
change collects symbol versions into .symversions files and merges
them in link-vmlinux.sh where they are all linked into vmlinux.o at
the same time.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-4-samitolvanen@google.com
2021-01-14 08:21:08 -08:00
Sami Tolvanen
dc5723b02e kbuild: add support for Clang LTO
This change adds build system support for Clang's Link Time
Optimization (LTO). With -flto, instead of ELF object files, Clang
produces LLVM bitcode, which is compiled into native code at link
time, allowing the final binary to be optimized globally. For more
details, see:

  https://llvm.org/docs/LinkTimeOptimization.html

The Kconfig option CONFIG_LTO_CLANG is implemented as a choice,
which defaults to LTO being disabled. To use LTO, the architecture
must select ARCH_SUPPORTS_LTO_CLANG and support:

  - compiling with Clang,
  - compiling all assembly code with Clang's integrated assembler,
  - and linking with LLD.

While using CONFIG_LTO_CLANG_FULL results in the best runtime
performance, the compilation is not scalable in time or
memory. CONFIG_LTO_CLANG_THIN enables ThinLTO, which allows
parallel optimization and faster incremental builds. ThinLTO is
used by default if the architecture also selects
ARCH_SUPPORTS_LTO_CLANG_THIN:

  https://clang.llvm.org/docs/ThinLTO.html

To enable LTO, LLVM tools must be used to handle bitcode files, by
passing LLVM=1 and LLVM_IAS=1 options to make:

  $ make LLVM=1 LLVM_IAS=1 defconfig
  $ scripts/config -e LTO_CLANG_THIN
  $ make LLVM=1 LLVM_IAS=1

To prepare for LTO support with other compilers, common parts are
gated behind the CONFIG_LTO option, and LTO can be disabled for
specific files by filtering out CC_FLAGS_LTO.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-3-samitolvanen@google.com
2021-01-14 08:21:08 -08:00
Linus Torvalds
7c53f6b671 Linux 5.11-rc3 2021-01-10 14:34:50 -08:00
Sami Tolvanen
3b15cdc159 tracing: move function tracer options to Kconfig
Move function tracer options to Kconfig to make it easier to add
new methods for generating __mcount_loc, and to make the options
available also when building kernel modules.

Note that FTRACE_MCOUNT_USE_* options are updated on rebuild and
therefore, work even if the .config was generated in a different
environment.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-2-samitolvanen@google.com
2021-01-08 15:59:02 -08:00
Linus Torvalds
e71ba9452f Linux 5.11-rc2 2021-01-03 15:55:30 -08:00
Linus Torvalds
5c8fe583cc Linux 5.11-rc1 2020-12-27 15:30:22 -08:00
Linus Torvalds
7b95f0563a Kbuild updates for v5.11
- Use /usr/bin/env for shebang lines in scripts
 
  - Remove useless -Wnested-externs warning flag
 
  - Update documents
 
  - Refactor log handling in modpost
 
  - Stop building modules without MODULE_LICENSE() tag
 
  - Make the insane combination of 'static' and EXPORT_SYMBOL an error
 
  - Improve genksyms to handle _Static_assert()
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Merge tag 'kbuild-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Use /usr/bin/env for shebang lines in scripts

 - Remove useless -Wnested-externs warning flag

 - Update documents

 - Refactor log handling in modpost

 - Stop building modules without MODULE_LICENSE() tag

 - Make the insane combination of 'static' and EXPORT_SYMBOL an error

 - Improve genksyms to handle _Static_assert()

* tag 'kbuild-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  Documentation/kbuild: Document platform dependency practises
  Documentation/kbuild: Document COMPILE_TEST dependencies
  genksyms: Ignore module scoped _Static_assert()
  modpost: turn static exports into error
  modpost: turn section mismatches to error from fatal()
  modpost: change license incompatibility to error() from fatal()
  modpost: turn missing MODULE_LICENSE() into error
  modpost: refactor error handling and clarify error/fatal difference
  modpost: rename merror() to error()
  kbuild: don't hardcode depmod path
  kbuild: doc: document subdir-y syntax
  kbuild: doc: clarify the difference between extra-y and always-y
  kbuild: doc: split if_changed explanation to a separate section
  kbuild: doc: merge 'Special Rules' and 'Custom kbuild commands' sections
  kbuild: doc: fix 'List directories to visit when descending' section
  kbuild: doc: replace arch/$(ARCH)/ with arch/$(SRCARCH)/
  kbuild: doc: update the description about kbuild Makefiles
  Makefile.extrawarn: remove -Wnested-externs warning
  tweewide: Fix most Shebang lines
2020-12-22 14:02:39 -08:00
Dominique Martinet
436e980e2e kbuild: don't hardcode depmod path
depmod is not guaranteed to be in /sbin, just let make look for
it in the path like all the other invoked programs

Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-12-21 13:57:08 +09:00
Linus Torvalds
2c85ebc57b Linux 5.10 2020-12-13 14:41:30 -08:00
Linus Torvalds
0477e92881 Linux 5.10-rc7 2020-12-06 14:25:12 -08:00
Linus Torvalds
e6585a4939 Kbuild fixes for v5.10 (2nd)
- Move -Wcast-align to W=3, which tends to be false-positive and there
    is no tree-wide solution.
 
  - Pass -fmacro-prefix-map to KBUILD_CPPFLAGS because it is a preprocessor
    option and makes sense for .S files as well.
 
  - Disable -gdwarf-2 for Clang's integrated assembler to avoid warnings.
 
  - Disable --orphan-handling=warn for LLD 10.0.1 to avoid warnings.
 
  - Fix undesirable line breaks in *.mod files.
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Merge tag 'kbuild-fixes-v5.10-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - Move -Wcast-align to W=3, which tends to be false-positive and there
   is no tree-wide solution.

 - Pass -fmacro-prefix-map to KBUILD_CPPFLAGS because it is a
   preprocessor option and makes sense for .S files as well.

 - Disable -gdwarf-2 for Clang's integrated assembler to avoid warnings.

 - Disable --orphan-handling=warn for LLD 10.0.1 to avoid warnings.

 - Fix undesirable line breaks in *.mod files.

* tag 'kbuild-fixes-v5.10-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: avoid split lines in .mod files
  kbuild: Disable CONFIG_LD_ORPHAN_WARN for ld.lld 10.0.1
  kbuild: Hoist '--orphan-handling' into Kconfig
  Kbuild: do not emit debug info for assembly with LLVM_IAS=1
  kbuild: use -fmacro-prefix-map for .S sources
  Makefile.extrawarn: move -Wcast-align to W=3
2020-12-06 10:31:39 -08:00
Nathan Chancellor
59612b24f7 kbuild: Hoist '--orphan-handling' into Kconfig
Currently, '--orphan-handling=warn' is spread out across four different
architectures in their respective Makefiles, which makes it a little
unruly to deal with in case it needs to be disabled for a specific
linker version (in this case, ld.lld 10.0.1).

To make it easier to control this, hoist this warning into Kconfig and
the main Makefile so that disabling it is simpler, as the warning will
only be enabled in a couple places (main Makefile and a couple of
compressed boot folders that blow away LDFLAGS_vmlinx) and making it
conditional is easier due to Kconfig syntax. One small additional
benefit of this is saving a call to ld-option on incremental builds
because we will have already evaluated it for CONFIG_LD_ORPHAN_WARN.

To keep the list of supported architectures the same, introduce
CONFIG_ARCH_WANT_LD_ORPHAN_WARN, which an architecture can select to
gain this automatically after all of the sections are specified and size
asserted. A special thanks to Kees Cook for the help text on this
config.

Link: https://github.com/ClangBuiltLinux/linux/issues/1187
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-12-01 22:45:36 +09:00
Linus Torvalds
b650545978 Linux 5.10-rc6 2020-11-29 15:50:50 -08:00
Linus Torvalds
45e885c439 Kbuild fixes for v5.10
- Remove unused OBJSIZE variable.
 
  - Fix rootless deb-pkg build in a setgid directory.
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Merge tag 'kbuild-fixes-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - Remove unused OBJSIZE variable.

 - Fix rootless deb-pkg build in a setgid directory.

* tag 'kbuild-fixes-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  builddeb: Fix rootless build in setuid/setgid directory
  kbuild: remove unused OBJSIZE
2020-11-28 10:42:30 -08:00
Nick Desaulniers
b8a9092330 Kbuild: do not emit debug info for assembly with LLVM_IAS=1
Clang's integrated assembler produces the warning for assembly files:

warning: DWARF2 only supports one section per compilation unit

If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for
assembly sources (it is still emitted for C sources).  This will be
re-enabled for newer DWARF versions in a follow up patch.

Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with
LLVM=1 LLVM_IAS=1 for x86_64 and arm64.

Cc: <stable@vger.kernel.org>
Link: https://github.com/ClangBuiltLinux/linux/issues/716
Reported-by: Dmitry Golovin <dima@golovin.in>
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Suggested-by: Dmitry Golovin <dima@golovin.in>
Suggested-by: Nathan Chancellor <natechancellor@gmail.com>
Suggested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Fangrui Song <maskray@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-11-25 03:41:26 +09:00
Denys Zagorui
a716bd7432 kbuild: use -fmacro-prefix-map for .S sources
Follow-up to commit a73619a845 ("kbuild: use -fmacro-prefix-map to
make __FILE__ a relative path"). Assembler sources also use __FILE__
macro so this flag should be also applied to those sources.

Signed-off-by: Denys Zagorui <dzagorui@cisco.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-11-25 03:41:17 +09:00
Linus Torvalds
418baf2c28 Linux 5.10-rc5 2020-11-22 15:36:08 -08:00
Linus Torvalds
09162bc32c Linux 5.10-rc4 2020-11-15 16:44:31 -08:00
Linus Torvalds
f8394f232b Linux 5.10-rc3 2020-11-08 16:10:16 -08:00
Vasily Gorbik
d9b5665fb3 kbuild: remove unused OBJSIZE
The "size" tool has been solely used by s390 to enforce .bss section usage
restrictions in early startup code. Since commit 980d5f9ab3 ("s390/boot:
enable .bss section for compressed kernel") and commit 2e83e0eb85
("s390: clean .bss before running uncompressed kernel") these restrictions
have been lifted for the decompressor and uncompressed kernel and the
size tool is now unused.

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-11-02 11:31:00 +09:00
Linus Torvalds
3cea11cd5e Linux 5.10-rc2 2020-11-01 14:43:51 -08:00
Linus Torvalds
3650b228f8 Linux 5.10-rc1 2020-10-25 15:14:11 -07:00
Linus Torvalds
746b25b1aa Kbuild updates for v5.10
- Support 'make compile_commands.json' to generate the compilation
    database more easily, avoiding stale entries
 
  - Support 'make clang-analyzer' and 'make clang-tidy' for static checks
    using clang-tidy
 
  - Preprocess scripts/modules.lds.S to allow CONFIG options in the module
    linker script
 
  - Drop cc-option tests from compiler flags supported by our minimal
    GCC/Clang versions
 
  - Use always 12-digits commit hash for CONFIG_LOCALVERSION_AUTO=y
 
  - Use sha1 build id for both BFD linker and LLD
 
  - Improve deb-pkg for reproducible builds and rootless builds
 
  - Remove stale, useless scripts/namespace.pl
 
  - Turn -Wreturn-type warning into error
 
  - Fix build error of deb-pkg when CONFIG_MODULES=n
 
  - Replace 'hostname' command with more portable 'uname -n'
 
  - Various Makefile cleanups
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Merge tag 'kbuild-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Support 'make compile_commands.json' to generate the compilation
   database more easily, avoiding stale entries

 - Support 'make clang-analyzer' and 'make clang-tidy' for static checks
   using clang-tidy

 - Preprocess scripts/modules.lds.S to allow CONFIG options in the
   module linker script

 - Drop cc-option tests from compiler flags supported by our minimal
   GCC/Clang versions

 - Use always 12-digits commit hash for CONFIG_LOCALVERSION_AUTO=y

 - Use sha1 build id for both BFD linker and LLD

 - Improve deb-pkg for reproducible builds and rootless builds

 - Remove stale, useless scripts/namespace.pl

 - Turn -Wreturn-type warning into error

 - Fix build error of deb-pkg when CONFIG_MODULES=n

 - Replace 'hostname' command with more portable 'uname -n'

 - Various Makefile cleanups

* tag 'kbuild-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (34 commits)
  kbuild: Use uname for LINUX_COMPILE_HOST detection
  kbuild: Only add -fno-var-tracking-assignments for old GCC versions
  kbuild: remove leftover comment for filechk utility
  treewide: remove DISABLE_LTO
  kbuild: deb-pkg: clean up package name variables
  kbuild: deb-pkg: do not build linux-headers package if CONFIG_MODULES=n
  kbuild: enforce -Werror=return-type
  scripts: remove namespace.pl
  builddeb: Add support for all required debian/rules targets
  builddeb: Enable rootless builds
  builddeb: Pass -n to gzip for reproducible packages
  kbuild: split the build log of kallsyms
  kbuild: explicitly specify the build id style
  scripts/setlocalversion: make git describe output more reliable
  kbuild: remove cc-option test of -Werror=date-time
  kbuild: remove cc-option test of -fno-stack-check
  kbuild: remove cc-option test of -fno-strict-overflow
  kbuild: move CFLAGS_{KASAN,UBSAN,KCSAN} exports to relevant Makefiles
  kbuild: remove redundant CONFIG_KASAN check from scripts/Makefile.kasan
  kbuild: do not create built-in objects for external module builds
  ...
2020-10-22 13:13:57 -07:00
Mark Wielaard
121c5d08d5 kbuild: Only add -fno-var-tracking-assignments for old GCC versions
Some old GCC versions between 4.5.0 and 4.9.1 might miscompile code
with -fvar-tracking-assingments (which is enabled by default with -g -O2).
Commit 2062afb4f8 ("Fix gcc-4.9.0 miscompilation of load_balance()
in scheduler") added -fno-var-tracking-assignments unconditionally to
work around this. But newer versions of GCC no longer have this bug, so
only add it for versions of GCC before 5.0. This allows various tools
such as a perf probe or gdb debuggers or systemtap to resolve variable
locations using dwarf locations in more code.

Signed-off-by: Mark Wielaard <mark@klomp.org>
Acked-by: Ian Rogers <irogers@google.com>
Reviewed-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-10-21 00:28:53 +09:00
Linus Torvalds
9ff9b0d392 networking changes for the 5.10 merge window
Add redirect_neigh() BPF packet redirect helper, allowing to limit stack
 traversal in common container configs and improving TCP back-pressure.
 Daniel reports ~10Gbps => ~15Gbps single stream TCP performance gain.
 
 Expand netlink policy support and improve policy export to user space.
 (Ge)netlink core performs request validation according to declared
 policies. Expand the expressiveness of those policies (min/max length
 and bitmasks). Allow dumping policies for particular commands.
 This is used for feature discovery by user space (instead of kernel
 version parsing or trial and error).
 
 Support IGMPv3/MLDv2 multicast listener discovery protocols in bridge.
 
 Allow more than 255 IPv4 multicast interfaces.
 
 Add support for Type of Service (ToS) reflection in SYN/SYN-ACK
 packets of TCPv6.
 
 In Multi-patch TCP (MPTCP) support concurrent transmission of data
 on multiple subflows in a load balancing scenario. Enhance advertising
 addresses via the RM_ADDR/ADD_ADDR options.
 
 Support SMC-Dv2 version of SMC, which enables multi-subnet deployments.
 
 Allow more calls to same peer in RxRPC.
 
 Support two new Controller Area Network (CAN) protocols -
 CAN-FD and ISO 15765-2:2016.
 
 Add xfrm/IPsec compat layer, solving the 32bit user space on 64bit
 kernel problem.
 
 Add TC actions for implementing MPLS L2 VPNs.
 
 Improve nexthop code - e.g. handle various corner cases when nexthop
 objects are removed from groups better, skip unnecessary notifications
 and make it easier to offload nexthops into HW by converting
 to a blocking notifier.
 
 Support adding and consuming TCP header options by BPF programs,
 opening the doors for easy experimental and deployment-specific
 TCP option use.
 
 Reorganize TCP congestion control (CC) initialization to simplify life
 of TCP CC implemented in BPF.
 
 Add support for shipping BPF programs with the kernel and loading them
 early on boot via the User Mode Driver mechanism, hence reusing all the
 user space infra we have.
 
 Support sleepable BPF programs, initially targeting LSM and tracing.
 
 Add bpf_d_path() helper for returning full path for given 'struct path'.
 
 Make bpf_tail_call compatible with bpf-to-bpf calls.
 
 Allow BPF programs to call map_update_elem on sockmaps.
 
 Add BPF Type Format (BTF) support for type and enum discovery, as
 well as support for using BTF within the kernel itself (current use
 is for pretty printing structures).
 
 Support listing and getting information about bpf_links via the bpf
 syscall.
 
 Enhance kernel interfaces around NIC firmware update. Allow specifying
 overwrite mask to control if settings etc. are reset during update;
 report expected max time operation may take to users; support firmware
 activation without machine reboot incl. limits of how much impact
 reset may have (e.g. dropping link or not).
 
 Extend ethtool configuration interface to report IEEE-standard
 counters, to limit the need for per-vendor logic in user space.
 
 Adopt or extend devlink use for debug, monitoring, fw update
 in many drivers (dsa loop, ice, ionic, sja1105, qed, mlxsw,
 mv88e6xxx, dpaa2-eth).
 
 In mlxsw expose critical and emergency SFP module temperature alarms.
 Refactor port buffer handling to make the defaults more suitable and
 support setting these values explicitly via the DCBNL interface.
 
 Add XDP support for Intel's igb driver.
 
 Support offloading TC flower classification and filtering rules to
 mscc_ocelot switches.
 
 Add PTP support for Marvell Octeontx2 and PP2.2 hardware, as well as
 fixed interval period pulse generator and one-step timestamping in
 dpaa-eth.
 
 Add support for various auth offloads in WiFi APs, e.g. SAE (WPA3)
 offload.
 
 Add Lynx PHY/PCS MDIO module, and convert various drivers which have
 this HW to use it. Convert mvpp2 to split PCS.
 
 Support Marvell Prestera 98DX3255 24-port switch ASICs, as well as
 7-port Mediatek MT7531 IP.
 
 Add initial support for QCA6390 and IPQ6018 in ath11k WiFi driver,
 and wcn3680 support in wcn36xx.
 
 Improve performance for packets which don't require much offloads
 on recent Mellanox NICs by 20% by making multiple packets share
 a descriptor entry.
 
 Move chelsio inline crypto drivers (for TLS and IPsec) from the crypto
 subtree to drivers/net. Move MDIO drivers out of the phy directory.
 
 Clean up a lot of W=1 warnings, reportedly the actively developed
 subsections of networking drivers should now build W=1 warning free.
 
 Make sure drivers don't use in_interrupt() to dynamically adapt their
 code. Convert tasklets to use new tasklet_setup API (sadly this
 conversion is not yet complete).
 
 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-next-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from Jakub Kicinski:

 - Add redirect_neigh() BPF packet redirect helper, allowing to limit
   stack traversal in common container configs and improving TCP
   back-pressure.

   Daniel reports ~10Gbps => ~15Gbps single stream TCP performance gain.

 - Expand netlink policy support and improve policy export to user
   space. (Ge)netlink core performs request validation according to
   declared policies. Expand the expressiveness of those policies
   (min/max length and bitmasks). Allow dumping policies for particular
   commands. This is used for feature discovery by user space (instead
   of kernel version parsing or trial and error).

 - Support IGMPv3/MLDv2 multicast listener discovery protocols in
   bridge.

 - Allow more than 255 IPv4 multicast interfaces.

 - Add support for Type of Service (ToS) reflection in SYN/SYN-ACK
   packets of TCPv6.

 - In Multi-patch TCP (MPTCP) support concurrent transmission of data on
   multiple subflows in a load balancing scenario. Enhance advertising
   addresses via the RM_ADDR/ADD_ADDR options.

 - Support SMC-Dv2 version of SMC, which enables multi-subnet
   deployments.

 - Allow more calls to same peer in RxRPC.

 - Support two new Controller Area Network (CAN) protocols - CAN-FD and
   ISO 15765-2:2016.

 - Add xfrm/IPsec compat layer, solving the 32bit user space on 64bit
   kernel problem.

 - Add TC actions for implementing MPLS L2 VPNs.

 - Improve nexthop code - e.g. handle various corner cases when nexthop
   objects are removed from groups better, skip unnecessary
   notifications and make it easier to offload nexthops into HW by
   converting to a blocking notifier.

 - Support adding and consuming TCP header options by BPF programs,
   opening the doors for easy experimental and deployment-specific TCP
   option use.

 - Reorganize TCP congestion control (CC) initialization to simplify
   life of TCP CC implemented in BPF.

 - Add support for shipping BPF programs with the kernel and loading
   them early on boot via the User Mode Driver mechanism, hence reusing
   all the user space infra we have.

 - Support sleepable BPF programs, initially targeting LSM and tracing.

 - Add bpf_d_path() helper for returning full path for given 'struct
   path'.

 - Make bpf_tail_call compatible with bpf-to-bpf calls.

 - Allow BPF programs to call map_update_elem on sockmaps.

 - Add BPF Type Format (BTF) support for type and enum discovery, as
   well as support for using BTF within the kernel itself (current use
   is for pretty printing structures).

 - Support listing and getting information about bpf_links via the bpf
   syscall.

 - Enhance kernel interfaces around NIC firmware update. Allow
   specifying overwrite mask to control if settings etc. are reset
   during update; report expected max time operation may take to users;
   support firmware activation without machine reboot incl. limits of
   how much impact reset may have (e.g. dropping link or not).

 - Extend ethtool configuration interface to report IEEE-standard
   counters, to limit the need for per-vendor logic in user space.

 - Adopt or extend devlink use for debug, monitoring, fw update in many
   drivers (dsa loop, ice, ionic, sja1105, qed, mlxsw, mv88e6xxx,
   dpaa2-eth).

 - In mlxsw expose critical and emergency SFP module temperature alarms.
   Refactor port buffer handling to make the defaults more suitable and
   support setting these values explicitly via the DCBNL interface.

 - Add XDP support for Intel's igb driver.

 - Support offloading TC flower classification and filtering rules to
   mscc_ocelot switches.

 - Add PTP support for Marvell Octeontx2 and PP2.2 hardware, as well as
   fixed interval period pulse generator and one-step timestamping in
   dpaa-eth.

 - Add support for various auth offloads in WiFi APs, e.g. SAE (WPA3)
   offload.

 - Add Lynx PHY/PCS MDIO module, and convert various drivers which have
   this HW to use it. Convert mvpp2 to split PCS.

 - Support Marvell Prestera 98DX3255 24-port switch ASICs, as well as
   7-port Mediatek MT7531 IP.

 - Add initial support for QCA6390 and IPQ6018 in ath11k WiFi driver,
   and wcn3680 support in wcn36xx.

 - Improve performance for packets which don't require much offloads on
   recent Mellanox NICs by 20% by making multiple packets share a
   descriptor entry.

 - Move chelsio inline crypto drivers (for TLS and IPsec) from the
   crypto subtree to drivers/net. Move MDIO drivers out of the phy
   directory.

 - Clean up a lot of W=1 warnings, reportedly the actively developed
   subsections of networking drivers should now build W=1 warning free.

 - Make sure drivers don't use in_interrupt() to dynamically adapt their
   code. Convert tasklets to use new tasklet_setup API (sadly this
   conversion is not yet complete).

* tag 'net-next-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2583 commits)
  Revert "bpfilter: Fix build error with CONFIG_BPFILTER_UMH"
  net, sockmap: Don't call bpf_prog_put() on NULL pointer
  bpf, selftest: Fix flaky tcp_hdr_options test when adding addr to lo
  bpf, sockmap: Add locking annotations to iterator
  netfilter: nftables: allow re-computing sctp CRC-32C in 'payload' statements
  net: fix pos incrementment in ipv6_route_seq_next
  net/smc: fix invalid return code in smcd_new_buf_create()
  net/smc: fix valid DMBE buffer sizes
  net/smc: fix use-after-free of delayed events
  bpfilter: Fix build error with CONFIG_BPFILTER_UMH
  cxgb4/ch_ipsec: Replace the module name to ch_ipsec from chcr
  net: sched: Fix suspicious RCU usage while accessing tcf_tunnel_info
  bpf: Fix register equivalence tracking.
  rxrpc: Fix loss of final ack on shutdown
  rxrpc: Fix bundle counting for exclusive connections
  netfilter: restore NF_INET_NUMHOOKS
  ibmveth: Identify ingress large send packets.
  ibmveth: Switch order of ibmveth_helper calls.
  cxgb4: handle 4-tuple PEDIT to NAT mode translation
  selftests: Add VRF route leaking tests
  ...
2020-10-15 18:42:13 -07:00
Nick Desaulniers
4c207c50ea Revert "kbuild: disable clang's default use of -fmerge-all-constants"
This reverts commit 87e0d4f0f3.

-fno-merge-all-constants has been the default since clang-6; the minimum
supported version of clang in the kernel is clang-10 (10.0.1).

Suggested-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Fangrui Song <maskray@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lkml.kernel.org/r/20200902225911.209899-3-ndesaulniers@google.com
Link: https://reviews.llvm.org/rL329300.
Link: https://github.com/ClangBuiltLinux/linux/issues/9
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-13 18:38:26 -07:00
Olaf Hering
172aad81a8 kbuild: enforce -Werror=return-type
Catch errors which at least gcc tolerates by default:
 warning: 'return' with no value, in function returning non-void [-Wreturn-type]

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-10-12 09:24:11 +09:00
Linus Torvalds
bbf5c97901 Linux 5.9 2020-10-11 14:15:50 -07:00
Jacob Keller
7dfbea4c46 scripts: remove namespace.pl
namespace.pl is intended to help locate symbols which are defined but
are not used externally. The goal is to avoid bloat of the namespace in
the resulting kernel image.

The script relies on object data, and only finds unused symbols for the
configuration used to generate that object data. This results in a lot
of false positive warnings such as symbols only used by a single
architecture, or symbols which are used externally only under certain
configurations.

Running namespace.pl using allyesconfig, allmodconfig, and
x86_64_defconfig yields the following results:

* allmodconfig
  * 11122 unique symbol names with no external reference
  * 1194 symbols listed as multiply defined
  * 214 symbols it can't resolve
* allyesconfig
  * 10997 unique symbol names with no external reference
  * 1194 symbols listed as multiply defined
  * 214 symbols it can't resolve
* x86_64_defconfig
  * 5757 unique symbol names with no external reference
  * 528 symbols listed as multiply defined
  * 154 symbols it can't resolve

The script also has no way to easily limit the scope of the checks to
a given subset of the kernel, such as only checking for symbols defined
within a module or subsystem.

Discussion on public mailing lists seems to indicate that many view the
tool output as suspect or not very useful (see discussions at [1] and
[2] for further context).

As described by Masahiro Yamada at [2], namespace.pl provides 3 types of
checks: listing multiply defined symbols, resolving external symbols,
and warnings about symbols with no reference.

The first category of issues is easily caught by the linker as any set
of multiply defined symbols should fail to link. The second category of
issues is also caught by linking, as undefined symbols would cause
issues. Even with modules, these types of issues where a module relies
on an external symbol are caught by modpost.

The remaining category of issues reported is the list of symbols with no
external reference, and is the primary motivation of this script.
However, it ought to be clear from the above examples that the output is
difficult to sort through. Even allyesconfig has ~10000 entries.

The current submit-checklist indicates that patches ought to go through
namespacecheck and fix any new issues arising. But that itself presents
problems. As described at [1], many cases of reports are due to
configuration where a function is used externally by some configuration
settings. Prominent maintainers appear to dislike changes modify code
such that symbols become static based on CONFIG_* flags ([3], and [4])

One possible solution is to adjust the advice and indicate that we only
care about the output of namespacecheck on allyesconfig or allmodconfig
builds...

However, given the discussion at [2], I suspect that few people are
actively using this tool. It doesn't have a maintainer in the
MAINTAINERS flie, and it produces so many warnings for unused symbols
that it is difficult to use effectively. Thus, I propose we simply
remove it.

[1] https://lore.kernel.org/netdev/20200708164812.384ae8ea@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com/
[2] https://lore.kernel.org/lkml/20190129204319.15238-1-jacob.e.keller@intel.com/
[3] https://lore.kernel.org/netdev/20190828.154744.2058157956381129672.davem@davemloft.net/
[4] https://lore.kernel.org/netdev/20190827210928.576c5fef@cakuba.netronome.com/

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-10-12 01:58:53 +09:00
Bill Wendling
a968433723 kbuild: explicitly specify the build id style
ld's --build-id defaults to "sha1" style, while lld defaults to "fast".
The build IDs are very different between the two, which may confuse
programs that reference them.

Signed-off-by: Bill Wendling <morbo@google.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-10-09 23:57:30 +09:00
David S. Miller
8b0308fe31 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Rejecting non-native endian BTF overlapped with the addition
of support for it.

The rest were more simple overlapping changes, except the
renesas ravb binding update, which had to follow a file
move as well as a YAML conversion.

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-10-05 18:40:01 -07:00
Linus Torvalds
549738f15d Linux 5.9-rc8 2020-10-04 16:04:34 -07:00
Linus Torvalds
a1b8638ba1 Linux 5.9-rc7 2020-09-27 14:38:10 -07:00
Masahiro Yamada
87de84c914 kbuild: remove cc-option test of -Werror=date-time
The minimal compiler versions, GCC 4.9 and Clang 10 support this flag.

Here is the godbolt:
https://godbolt.org/z/xvjcMa

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Will Deacon <will@kernel.org>
2020-09-25 00:36:50 +09:00
Masahiro Yamada
7d4eb0d8e2 kbuild: remove cc-option test of -fno-stack-check
The minimal compiler version, GCC 4.9 supports this flag.

Nathan Chancellor pointed out:
 "This flag is technically ignored by clang (see commit
 05b0798916f01690b5903302e51f3136274e291f) but that obviously
 does not matter for the sake of this."

Here is the godbolt:
https://godbolt.org/z/59cK6o

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
2020-09-25 00:36:50 +09:00
Masahiro Yamada
8b42cf2fde kbuild: remove cc-option test of -fno-strict-overflow
The minimal compiler versions, GCC 4.9 and Clang 10 support this flag.

Here is the godbolt:
https://godbolt.org/z/odq8h9

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Will Deacon <will@kernel.org>
2020-09-25 00:36:50 +09:00
Masahiro Yamada
bb2732112b kbuild: move CFLAGS_{KASAN,UBSAN,KCSAN} exports to relevant Makefiles
Move CFLAGS_KASAN*, CFLAGS_UBSAN, CFLAGS_KCSAN to Makefile.kasan,
Makefile.ubsan, Makefile.kcsan, respectively.

This commit also avoids the same -fsanitize=* flags being added to
CFLAGS_UBSAN multiple times.

Prior to this commit, the ubsan flags were appended by the '+='
operator, without any initialization. Some build targets such as
'make bindeb-pkg' recurses to the top Makefile, and ended up with
adding the same flags to CFLAGS_UBSAN twice.

Clear CFLAGS_UBSAN with ':=' to make it a simply expanded variable.
This is better than a recursively expanded variable, which evaluates
$(call cc-option, ...) multiple times before Kbuild starts descending
to subdirectories.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Marco Elver <elver@google.com>
2020-09-25 00:36:50 +09:00
Masahiro Yamada
6212804f2d kbuild: do not create built-in objects for external module builds
'make M=/path/to/your/external/module' creates a pointless built-in.a
in the top of the external module directory because KBUILD_BUILTIN is
set to 1.

Clear KBUILD_BUILTIN when we are building external modules so that
'make M=...' and 'make M=... modules' work equivalently.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-09-25 00:36:49 +09:00