Commit Graph

856622 Commits

Author SHA1 Message Date
Masahiro Yamada
64a91907c8 kbuild: refactor scripts/Makefile.extrawarn
Instead of the warning-[123] magic, let's accumulate compiler options
to KBUILD_CFLAGS directly as the top Makefile does. I think this makes
it easier to understand what is going on in this file.

This commit slightly changes the behavior, I think all of which are OK.

[1] Currently, cc-option calls are needlessly evaluated. For example,
      warning-3 += $(call cc-option, -Wpacked-bitfield-compat)
    needs evaluating only when W=3, but it is actually evaluated for
    W=1, W=2 as well. With this commit, only relevant cc-option calls
    will be evaluated. This is a slight optimization.

[2] Currently, unsupported level like W=4 is checked by:
      $(error W=$(KBUILD_ENABLE_EXTRA_GCC_CHECKS) is unknown)
    This will no longer be checked, but I do not think it is a big
    deal.

[3] Currently, 4 Clang warnings (Winitializer-overrides, Wformat,
    Wsign-compare, Wformat-zero-length) are shown by any of W=1, W=2,
    and W=3. With this commit, they will be warned only by W=1. I
    think this is a more correct behavior since each warning belongs
    to only one group.

For understanding this commit correctly:

We have 3 warning groups, W=1, W=2, and W=3. You may think W=3 has a
higher level than W=1, but they are actually independent. If you like,
you can combine them like W=13. To enable all the warnings, you can
pass W=123. It is shown by 'make help', but not noticed much. Since we
support W= combination, there should not exist intersection among the
three groups. If we enable Winitializer-overrides for W=1, we do not
need to for W=2 or W=3. This is the reason why I think the change [3]
makes sense.

The documentation says -Winitializer-overrides is enabled by default.
(https://clang.llvm.org/docs/DiagnosticsReference.html#winitializer-overrides)
We negate it by passing -Wno-initializer-overrides for the normal
build, but we do not do that for W=1. This means, W=1 effectively
enables -Winitializer-overrides by the clang's default. The same for
the other three.

Add comments in case people are confused with the code.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2019-09-06 23:46:52 +09:00
Guillaume Tucker
60bef52c7a merge_config.sh: ignore unwanted grep errors
The merge_config.sh script verifies that all the config options have
their expected value in the resulting file and prints any issues as
warnings.  These checks aren't intended to be treated as errors given
the current implementation.  However, since "set -e" was added, if the
grep command to look for a config option does not find it the script
will then abort prematurely.

Handle the case where the grep exit status is non-zero by setting
ACTUAL_VAL to an empty string to restore previous functionality.

Fixes: cdfca82157 ("merge_config.sh: Check error codes from make")
Signed-off-by: Guillaume Tucker <guillaume.tucker@collabora.com>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-09-04 23:12:50 +09:00
Masahiro Yamada
54b8ae66ae kbuild: change *FLAGS_<basetarget>.o to take the path relative to $(obj)
Kbuild provides per-file compiler flag addition/removal:

  CFLAGS_<basetarget>.o
  CFLAGS_REMOVE_<basetarget>.o
  AFLAGS_<basetarget>.o
  AFLAGS_REMOVE_<basetarget>.o
  CPPFLAGS_<basetarget>.lds
  HOSTCFLAGS_<basetarget>.o
  HOSTCXXFLAGS_<basetarget>.o

The <basetarget> is the filename of the target with its directory and
suffix stripped.

This syntax comes into a trouble when two files with the same basename
appear in one Makefile, for example:

  obj-y += foo.o
  obj-y += dir/foo.o
  CFLAGS_foo.o := <some-flags>

Here, the <some-flags> applies to both foo.o and dir/foo.o

The real world problem is:

  scripts/kconfig/util.c
  scripts/kconfig/lxdialog/util.c

Both files are compiled into scripts/kconfig/mconf, but only the
latter should be given with the ncurses flags.

It is more sensible to use the relative path to the Makefile, like this:

  obj-y += foo.o
  CFLAGS_foo.o := <some-flags>
  obj-y += dir/foo.o
  CFLAGS_dir/foo.o := <other-flags>

At first, I attempted to replace $(basetarget) with $*. The $* variable
is replaced with the stem ('%') part in a pattern rule. This works with
most of cases, but does not for explicit rules.

For example, arch/ia64/lib/Makefile reuses rule_as_o_S in its own
explicit rules, so $* will be empty, resulting in ignoring the per-file
AFLAGS.

I introduced a new variable, target-stem, which can be used also from
explicit rules.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Marc Zyngier <maz@kernel.org>
2019-09-04 23:12:50 +09:00
Denis Efremov
6f02bdfc99 modpost: add NOFAIL to strndup
Add NOFAIL check for the strndup call, because the function
allocates memory and can return NULL. All calls to strdup in
modpost are checked with NOFAIL.

Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-09-04 22:55:42 +09:00
Heikki Krogerus
389c9af7f1 modpost: add guid_t type definition
Since guid_t is the recommended data type for UUIDs in
kernel (and I guess uuid_le is meant to be ultimately
replaced with it), it should be made available here as
well.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-09-04 22:55:42 +09:00
Masahiro Yamada
858805b336 kbuild: add $(BASH) to run scripts with bash-extension
CONFIG_SHELL falls back to sh when bash is not installed on the system,
but nobody is testing such a case since bash is usually installed.
So, shell scripts invoked by CONFIG_SHELL are only tested with bash.

It makes it difficult to test whether the hashbang #!/bin/sh is real.
For example, #!/bin/sh in arch/powerpc/kernel/prom_init_check.sh is
false. (I fixed it up)

Besides, some shell scripts invoked by CONFIG_SHELL use bash-extension
and #!/bin/bash is specified as the hashbang, while CONFIG_SHELL may
not always be set to bash.

Probably, the right thing to do is to introduce BASH, which is bash by
default, and always set CONFIG_SHELL to sh. Replace $(CONFIG_SHELL)
with $(BASH) for bash scripts.

If somebody tries to add bash-extension to a #!/bin/sh script, it will
be caught in testing because /bin/sh is a symlink to dash on some major
distributions.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-09-04 22:54:13 +09:00
Masahiro Yamada
8cc7af7514 kbuild: remove ARCH_{CPP,A,C}FLAGS
These flags were added by commit 61754c1875 ("kbuild: Allow arch
Makefiles to override {cpp,ld,c}flags") to allow ARC to override -O2.

We did not see any other usage after all. Now that ARC switched to
CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3, there is no more user of
these variables.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-09-04 10:01:17 +09:00
Masahiro Yamada
15f5db60a1 kbuild,arc: add CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3 for ARC
arch/arc/Makefile overrides -O2 with -O3. This is the only user of
ARCH_CFLAGS. There is no user of ARCH_CPPFLAGS or ARCH_AFLAGS.
My plan is to remove ARCH_{CPP,A,C}FLAGS after refactoring the ARC
Makefile.

Currently, ARC has no way to enable -Wmaybe-uninitialized because both
-O3 and -Os disable it. Enabling it will be useful for compile-testing.
This commit allows allmodconfig (, which defaults to -O2) to enable it.

Add CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y to all the defconfig files
in arch/arc/configs/ in order to keep the current config settings.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
2019-09-04 10:01:17 +09:00
Nathan Chancellor
e2079e93f5 kbuild: Do not enable -Wimplicit-fallthrough for clang for now
This functionally reverts commit bfd77145f3 ("Makefile: Convert
-Wimplicit-fallthrough=3 to just -Wimplicit-fallthrough for clang").

clang enabled support for -Wimplicit-fallthrough in C in r369414 [1],
which causes a lot of warnings when building the kernel for two reasons:

1. Clang does not support the /* fall through */ comments. There seems
   to be a general consensus in the LLVM community that this is not
   something they want to support. Joe Perches wrote a script to convert
   all of the comments to a "fallthrough" keyword that will be added to
   compiler_attributes.h [2] [3], which catches the vast majority of the
   comments. There doesn't appear to be any consensus in the kernel
   community when to do this conversion.

2. Clang and GCC disagree about falling through to final case statements
   with no content or cases that simply break:

   https://godbolt.org/z/c8csDu

   This difference contributes at least 50 warnings in an allyesconfig
   build for x86, not considering other architectures. This difference
   will need to be discussed to see which compiler is right [4] [5].

[1]: 1e0affb6e5
[2]: https://lore.kernel.org/lkml/61ddbb86d5e68a15e24ccb06d9b399bbf5ce2da7.camel@perches.com/
[3]: https://lore.kernel.org/lkml/1d2830aadbe9d8151728a7df5b88528fc72a0095.1564549413.git.joe@perches.com/
[4]: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91432
[5]: https://github.com/ClangBuiltLinux/linux/issues/636

Given these two problems need discussion and coordination, do not enable
-Wimplicit-fallthrough with clang right now. Add a comment to explain
what is going on as well. This commit should be reverted once these two
issues are fully flushed out and resolved.

Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-30 04:00:37 +09:00
Masahiro Yamada
4ca76945b0 kbuild: clean up subdir-ymn calculation in Makefile.clean
Remove some variables.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29 23:54:29 +09:00
Masahiro Yamada
687ac1fa31 kbuild: remove unneeded '+' marker from cmd_clean
This '+' was added a long time ago:

| commit c23e6bf05f7802e92fd3da69a1ed35e56f9c85bb (HEAD)
| Author: Kai Germaschewski <kai@tp1.ruhr-uni-bochum.de>
| Date:   Mon Oct 28 01:16:34 2002 -0600
|
|     kbuild: Fix a "make -j<N>" warning
|
| diff --git a/scripts/Makefile.clean b/scripts/Makefile.clean
| index 2c843e0380bc..e7c392fd5788 100644
| --- a/scripts/Makefile.clean
| +++ b/scripts/Makefile.clean
| @@ -42,7 +42,7 @@ quiet_cmd_clean = CLEAN   $(obj)
|
|  __clean: $(subdir-ymn)
|  ifneq ($(strip $(__clean-files) $(clean-rule)),)
| -        $(call cmd,clean)
| +        +$(call cmd,clean)
|  else
|          @:
|  endif

At that time, cmd_clean contained $(clean-rule), which was able to
invoke sub-make. That was why cleaning with the -j option showed:
warning: jobserver unavailable: using -j1.  Add '+' to parent make rule.

It is not the case any more; cmd_clean now just runs the 'rm' command.
The '+' marker is pointless.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29 23:54:29 +09:00
Masahiro Yamada
1634f2bfdb kbuild: remove clean-dirs syntax
The only the difference between clean-files and clean-dirs is the -r
option passed to the 'rm' command.

You can always pass -r, and then remove the clean-dirs syntax.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29 23:54:29 +09:00
Masahiro Yamada
36de077b20 kbuild: check clean srctree even earlier
Move the outputmakefile target to the leftmost in the prerequisite list
so that this is checked first. GNU Make processes the prerequisites
left to right.

GNU Make will keep to stick to this behavior, and it seems even
POSIX standard, according to this:
https://lists.gnu.org/archive/html/bug-make/2019-08/msg00030.html

The POSIX standard of make is available here:
https://pubs.opengroup.org/onlinepubs/9699919799/utilities/make.html

Of course, when the parallel option -j given, other targets will be run
simultaneously but it is nice to show the error as early as possible.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29 23:54:29 +09:00
Masahiro Yamada
a5139fb368 kbuild: remove prepare3 target
Now prepare3 does nothing but depends on include/config/kernel.release

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29 23:54:29 +09:00
Masahiro Yamada
e8e83a236d kbuild: move the clean srctree check to the outputmakefile target
With this commit, the error report is shown earlier, even before
running kconfig.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29 23:54:29 +09:00
Masahiro Yamada
1a475d5486 kbuild: clarify where to run make mrproper when out-of-tree fails
If you try out-of-tree build with an unclean source tree, Kbuild
suggests to run make mrproper. The path to the source tree may be
shown with a relative path, for example, "make O=foo" emits the
following:

  .. is not clean, please run 'make mrproper'
  in the '..' directory.

This is somewhat confusing if you ran "make O=foo" in the source tree.
Using the absolute path will be clearer.

This commit changes the error message like follows:

***
*** The source tree is not clean, please run 'make mrproper'
*** in /absolute/path/to/linux
***

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29 23:54:29 +09:00
Masahiro Yamada
621da4ba0e kbuild: Inform user to pass ARCH= for make mrproper only when necessary
Since commit 3a475b2166 ("kbuild: Inform user to pass ARCH= for make
mrproper"), if you try out-of-tree build with an unclean source tree,
it suggests to run 'make ARCH=<ARCH> mrproper'.

This looks odd when you are not cross-compiling the kernel. Show the
'ARCH=<ARCH>' part only when ARCH= was given from the command line.
If ARCH is the default (native build) or came from the environment,
it should simply suggest 'make mrproper' as before.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29 23:54:29 +09:00
Masahiro Yamada
59747fb869 kbuild: remove 'Using ... as source for kernel' message
You already know the location of the source tree without this message.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29 23:54:29 +09:00
Masahiro Yamada
9c3ad4c14f kbuild: get rid of $(realpath ...) from scripts/mkmakefile
Both relative path and absolute path have pros and cons. For example,
we can move the source and objtree around together by using the
relative path to the source tree.

Do not force the absolute path to the source tree. If you prefer the
absolute path, you can specify KBUILD_ABS_SRCTREE=1.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29 23:54:29 +09:00
Masahiro Yamada
bc7b752a7a kbuild: remove unneeded dependency for $(DOC_TARGETS)
Commit 415008af32 ("docs-rst: convert lsm from DocBook to ReST")
stopped using if_changed_rule. There is no more users of if_changed*
for the doc targets. Hence, fixdep is unneeded. Remove the dependency
on scripts_basic.

All the doc targets are phony. The dependency on FORCE is not needed
either.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29 23:54:29 +09:00
Masahiro Yamada
fc01adc416 kbuild: remove unneeded comments and code from scripts/basic/Makefile
Kbuild descends into scripts/basic/ even before the Kconfig.
I do not expect any other host programs added to this Makefile.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29 23:54:29 +09:00
Masahiro Yamada
ce3b487f60 init/Kconfig: rework help of CONFIG_CC_OPTIMIZE_FOR_SIZE
CONFIG_CC_OPTIMIZE_FOR_SIZE was originally an independent boolean
option, but commit 877417e6ff ("Kbuild: change CC_OPTIMIZE_FOR_SIZE
definition") turned it into a choice between _PERFORMANCE and _SIZE.

The phrase "If unsure, say N." sounds like an independent option.
Reword the help text to make it appropriate for the choice menu.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29 01:39:35 +09:00
Masahiro Yamada
d20558d1de docs: kbuild: remove cc-ldoption from document again
Commit 055efab312 ("kbuild: drop support for cc-ldoption") correctly
removed the cc-ldoption from Documentation/kbuild/makefiles.txt, but
commit cd238effef ("docs: kbuild: convert docs to ReST and rename
to *.rst") revived it. I guess it was a rebase mistake.

Remove it again.

Fixes: cd238effef ("docs: kbuild: convert docs to ReST and rename to *.rst")
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29 01:37:53 +09:00
Masahiro Yamada
4fef9dece5 docs: kbuild: fix invalid ReST syntax
I see the following warnings when I open this document with a ReST
viewer, retext:

/home/masahiro/ref/linux/Documentation/kbuild/makefiles.rst:1142: (WARNING/2) Inline emphasis start-string without end-string.
/home/masahiro/ref/linux/Documentation/kbuild/makefiles.rst:1152: (WARNING/2) Inline emphasis start-string without end-string.
/home/masahiro/ref/linux/Documentation/kbuild/makefiles.rst:1154: (WARNING/2) Inline emphasis start-string without end-string.

These hunks were added by commit e846f0dc57 ("kbuild: add support
for ensuring headers are self-contained") and commit 1e21cbfada
("kbuild: support header-test-pattern-y"), respectively. They were
written not for ReST but for the plain text, and merged via the
kbuild tree.

In the same development cycle, this document was converted to ReST
by commit cd238effef ("docs: kbuild: convert docs to ReST and rename
to *.rst"), and merged via the doc sub-system.

Merging them together into Linus' tree resulted in the current situation.

To fix the syntax, surround the asterisks with back-quotes, and
use :: for the code sample.

Fixes: 39ceda5ce1 ("Merge tag 'kbuild-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild")
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29 01:37:53 +09:00
Masahiro Yamada
3e4c6948e7 kbuild: remove unneeded '+' marker from kselftest-merge
This line contains $(MAKE), so Make knows that it will invoke sub-make
without help of the '+' marker.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-25 10:32:35 +09:00
Masahiro Yamada
000ec95fbe kbuild: pkg: rename scripts/package/Makefile to scripts/Makefile.package
scripts/package/Makefile does not use $(obj) or $(src) at all.
It actually generates files and directories in the top of $(objtree).
I do not see much sense in descending into scripts/package/.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-25 07:42:00 +09:00
Masahiro Yamada
6a4f6a26d3 kbuild: pkg: add package targets to PHONY instead of FORCE
These are not real targets. Adding them to PHONY is preferred.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-25 07:39:26 +09:00
Masahiro Yamada
46a63d4b0d kbuild: pkg: clean up package files/dirs from the top Makefile
I am not a big fan of the $(objtree)/ hack for clean-files/clean-dirs.

These are created in the top of $(objtree), so let's clean them up
from the top Makefile.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-25 07:39:21 +09:00
Mark Brown
cdfca82157 merge_config.sh: Check error codes from make
When we execute make after merging the configurations we ignore any
errors it produces causing whatever is running merge_config.sh to be
unaware of any failures.  This issue was noticed by Guillaume Tucker
while looking at problems with testing of clang only builds in KernelCI
which caused Kbuild to be unable to find a working host compiler.

This implementation was suggested by Yamada-san.

Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reported-by: Guillaume Tucker <guillaume.tucker@collabora.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-22 01:14:11 +09:00
Masahiro Yamada
eb27ea5ce7 kbuild: move modkern_{c,a}flags to Makefile.lib from Makefile.build
Makefile.lib is included by Makefile.modfinal as well as Makefile.build.

Move modkern_cflags to Makefile.lib in order to simplify cmd_cc_o_c
in Makefile.modfinal. Move modkern_cflags as well for consistency.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-22 01:14:11 +09:00
Masahiro Yamada
2ff2b7ec65 kbuild: add CONFIG_ASM_MODVERSIONS
Add CONFIG_ASM_MODVERSIONS. This allows to remove one if-conditional
nesting in scripts/Makefile.build.

scripts/Makefile.build is run every time Kbuild descends into a
sub-directory. So, I want to avoid $(wildcard ...) evaluation
where possible although computing $(wildcard ...) is so cheap that
it may not make measurable performance difference.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
2019-08-22 01:14:11 +09:00
Masahiro Yamada
a564bdeb5e .gitignore: ignore modules.order explicitly
The pattern '*.order' was added by commit c6025f4c8b ("kbuild: ignore
*.order files") to ignore modules.order files.

I do not see any other user of the '.order' extension.

Ignore 'modules.order' explicitly instead of '*.order'.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-22 01:14:11 +09:00
Masahiro Yamada
9b9a3f20cb kbuild: split final module linking out into Makefile.modfinal
I think splitting the modpost and linking modules into separate
Makefiles will be useful especially when more complex build steps
come in. The main motivation of this commit is to integrate the
proposed klp-convert feature cleanly.

I moved the logging 'Building modules, stage 2.' to Makefile.modpost
to avoid the code duplication although I do not know whether or not
this message is needed in the first place.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-22 01:08:15 +09:00
Masahiro Yamada
10df063855 kbuild: rebuild modules when module linker scripts are updated
Currently, the timestamp of module linker scripts are not checked.
Add them to the dependency of modules so they are correctly rebuilt.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-21 21:05:21 +09:00
Masahiro Yamada
888f0c346f kbuild: move KBUILD_LDS, KBUILD_VMLINUX_{OBJS,LIBS} to makefiles.rst
These three variables are not intended to be tweaked by users.
Move them from kbuild.rst to makefiles.rst.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-21 21:05:21 +09:00
Masahiro Yamada
cbdf59ad65 treewide: remove dummy Makefiles for single targets
Now that the single target build descends into sub-directories in the
same way as the normal build, these dummy Makefiles are not needed
any more.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-21 21:05:21 +09:00
Masahiro Yamada
394053f4a4 kbuild: make single targets work more correctly
Currently, the single target build directly descends into the directory
of the target. For example,

  $ make foo/bar/baz.o

... directly descends into foo/bar/.

On the other hand, the normal build usually descends one directory at
a time, i.e. descends into foo/, and then foo/bar/.

This difference causes some problems.

[1] miss subdir-asflags-y, subdir-ccflags-y in upper Makefiles

    The options in subdir-{as,cc}flags-y take effect in the current
    and its sub-directories. In other words, they are inherited
    downward. In the example above, the single target will miss
    subdir-{as,cc}flags-y if they are defined in foo/Makefile.

[2] could be built in a different directory

    As Documentation/kbuild/modules.rst section 4.3 says, Kbuild can
    handle files that are spread over several sub-directories.

    The build rule of foo/bar/baz.o may not necessarily be specified in
    foo/bar/Makefile. It might be specifies in foo/Makefile as follows:

    [foo/Makefile]
    obj-y := bar/baz.o

    This often happens when a module is so big that its source files
    are divided into sub-directories.

    In this case, there is no Makefile in the foo/bar/ directory, yet
    the single target descends into foo/bar/, then fails due to the
    missing Makefile. You can still do 'make foo/bar/' for partial
    building, but cannot do 'make foo/bar/baz.s'. I believe the single
    target '%.s' is a useful feature for inspecting the compiler output.

    Some modules work around this issue by putting an empty Makefile
    in every sub-directory.

This commit fixes those problems by making the single target build
descend in the same way as the normal build does.

Another change is the single target build will observe the CONFIG
options. Previously, it allowed users to build the foo.o even when
the corresponding CONFIG_FOO is disabled:

   obj-$(CONFIG_FOO) += foo.o

In the new behavior, the single target build will just fail and show
"No rule to make target ..." (or "Nothing to be done for ..." if the
stale object already exists, but cannot be updated).

The disadvantage of this commit is the build speed. Now that the
single target build visits every directory and parses lots of
Makefiles, it is slower than before. (But, I hope it will not be
too slow.)

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-21 21:05:21 +09:00
Kees Cook
8959e39272 kbuild: Parameterize kallsyms generation and correct reporting
When kallsyms generation happens, temporary vmlinux outputs are linked
but the quiet make output didn't report it, giving the impression that
the prior command is taking longer than expected.

Instead, report the linking step explicitly. While at it, this
consolidates the repeated "kallsyms generation step" into a single
function and removes the existing copy/pasting.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-21 21:05:21 +09:00
Masahiro Yamada
c7c0eecf89 kbuild: re-implement detection of CONFIG options leaked to user-space
scripts/headers_check.pl can detect references to CONFIG options in
exported headers, but it has been disabled for more than a decade.

Reverting commit 7e3fa56141 ("kbuild: drop check for CONFIG_ in
headers_check") would emit the following warnings for headers_check
on x86:

usr/include/mtd/ubi-user.h:283: leaks CONFIG_MTD_UBI_BEB_LIMIT to userspace where it is not valid
usr/include/linux/cm4000_cs.h:26: leaks CONFIG_COMPAT to userspace where it is not valid
usr/include/linux/pkt_cls.h:301: leaks CONFIG_NET_CLS_ACT to userspace where it is not valid
usr/include/linux/videodev2.h:2465: leaks CONFIG_VIDEO_ADV_DEBUG to userspace where it is not valid
usr/include/linux/bpf.h:249: leaks CONFIG_EFFICIENT_UNALIGNED_ACCESS to userspace where it is not valid
usr/include/linux/bpf.h:819: leaks CONFIG_CGROUP_NET_CLASSID to userspace where it is not valid
usr/include/linux/bpf.h:1011: leaks CONFIG_IP_ROUTE_CLASSID to userspace where it is not valid
usr/include/linux/bpf.h:1742: leaks CONFIG_BPF_KPROBE_OVERRIDE to userspace where it is not valid
usr/include/linux/bpf.h:1747: leaks CONFIG_FUNCTION_ERROR_INJECTION to userspace where it is not valid
usr/include/linux/bpf.h:1936: leaks CONFIG_XFRM to userspace where it is not valid
usr/include/linux/bpf.h:2184: leaks CONFIG_BPF_LIRC_MODE2 to userspace where it is not valid
usr/include/linux/bpf.h:2210: leaks CONFIG_BPF_LIRC_MODE2 to userspace where it is not valid
usr/include/linux/bpf.h:2227: leaks CONFIG_SOCK_CGROUP_DATA to userspace where it is not valid
usr/include/linux/bpf.h:2311: leaks CONFIG_NET to userspace where it is not valid
usr/include/linux/bpf.h:2348: leaks CONFIG_NET to userspace where it is not valid
usr/include/linux/bpf.h:2422: leaks CONFIG_BPF_LIRC_MODE2 to userspace where it is not valid
usr/include/linux/bpf.h:2528: leaks CONFIG_NET to userspace where it is not valid
usr/include/linux/pktcdvd.h:37: leaks CONFIG_CDROM_PKTCDVD_WCACHE to userspace where it is not valid
usr/include/linux/hw_breakpoint.h:27: leaks CONFIG_HAVE_MIXED_BREAKPOINTS_REGS to userspace where it is not valid
usr/include/linux/raw.h:17: leaks CONFIG_MAX_RAW_DEVS to userspace where it is not valid
usr/include/linux/elfcore.h:62: leaks CONFIG_BINFMT_ELF_FDPIC to userspace where it is not valid
usr/include/linux/eventpoll.h:82: leaks CONFIG_PM_SLEEP to userspace where it is not valid
usr/include/linux/atmdev.h:104: leaks CONFIG_COMPAT to userspace where it is not valid
usr/include/asm-generic/unistd.h:651: leaks CONFIG_MMU to userspace where it is not valid
usr/include/asm-generic/bitsperlong.h:9: leaks CONFIG_64BIT to userspace where it is not valid
usr/include/asm-generic/fcntl.h:119: leaks CONFIG_64BIT to userspace where it is not valid
usr/include/asm/auxvec.h:14: leaks CONFIG_IA32_EMULATION to userspace where it is not valid
usr/include/asm/e820.h:14: leaks CONFIG_NODES_SHIFT to userspace where it is not valid
usr/include/asm/e820.h:39: leaks CONFIG_X86_PMEM_LEGACY to userspace where it is not valid
usr/include/asm/e820.h:49: leaks CONFIG_INTEL_TXT to userspace where it is not valid
usr/include/asm/mman.h:7: leaks CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS to userspace where it is not valid

Most of these are false positives because scripts/headers_check.pl
parses comment lines.

It is also false negative. arch/x86/include/uapi/asm/auxvec.h contains
CONFIG_IA32_EMULATION and CONFIG_X86_64, but the only former is reported.

It would be possible to fix scripts/headers_check.pl, of course.
However, we already have some duplicated checks between headers_check
and CONFIG_UAPI_HEADER_TEST. At this moment of time, there are still
dozens of headers excluded from the header test (usr/include/Makefile),
but we might be able to remove headers_check eventually.

I re-implemented it in scripts/headers_install.sh by using sed because
the most of code in scripts/headers_install.sh is written in sed.

This patch works like this:

[1] Run scripts/unifdef first because we need to drop the code
    surrounded by #ifdef __KERNEL__ ... #endif

[2] Remove all C style comments. The sed code is somewhat complicated
    since we need to deal with both single and multi line comments.

    Precisely speaking, a comment block is replaced with a space just
    in case.

      CONFIG_FOO/* this is a comment */CONFIG_BAR

    should be converted into:

      CONFIG_FOO CONFIG_BAR

    instead of:

      CONFIG_FOOCONFIG_BAR

[3] Match CONFIG_... pattern. It correctly matches to all CONFIG
    options that appear in a single line.

After this commit, this would detect the following warnings, all of
which are real ones.

warning: include/uapi/linux/pktcdvd.h: leak CONFIG_CDROM_PKTCDVD_WCACHE to user-space
warning: include/uapi/linux/hw_breakpoint.h: leak CONFIG_HAVE_MIXED_BREAKPOINTS_REGS to user-space
warning: include/uapi/linux/raw.h: leak CONFIG_MAX_RAW_DEVS to user-space
warning: include/uapi/linux/elfcore.h: leak CONFIG_BINFMT_ELF_FDPIC to user-space
warning: include/uapi/linux/eventpoll.h: leak CONFIG_PM_SLEEP to user-space
warning: include/uapi/linux/atmdev.h: leak CONFIG_COMPAT to user-space
warning: include/uapi/asm-generic/fcntl.h: leak CONFIG_64BIT to user-space
warning: arch/x86/include/uapi/asm/auxvec.h: leak CONFIG_IA32_EMULATION to user-space
warning: arch/x86/include/uapi/asm/auxvec.h: leak CONFIG_X86_64 to user-space
warning: arch/x86/include/uapi/asm/mman.h: leak CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS to user-space

However, it is not nice to show them right now. I created a list of
existing leakages. They are not warned, but a new leakage will be
blocked by the 0-day bot.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
2019-08-21 21:05:21 +09:00
Masahiro Yamada
76cd306d79 kbuild: unify clean-dirs rule for in-kernel and external module
Factor out the duplicated code for in-kernel and external module
cleaning.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-21 21:05:21 +09:00
Masahiro Yamada
c99f3918cf kbuild: unify vmlinux-dirs and module-dirs rules
The in-kernel build and external module build have similar code
for descending into sub-directories.

Factor out the code into the common place.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-21 21:05:21 +09:00
Masahiro Yamada
2042b5486b kbuild: unset variables in top Makefile instead of setting 0
There is no need to set 0 to variables such as config-targets,
mixed-targets, etc.

Unset instead of setting 0 in order to use 'ifdef' to test them.

I also renamed:

  config-targets  ->  config-build
  mixed-targets   ->  mixed-build
  dot-config      ->  need-config

to clarify what we are doing.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-21 21:05:21 +09:00
Masahiro Yamada
125d059b62 kbuild: do not descend to ./Kbuild when cleaning
'make clean' descends into ./Kbuild, but does not clean anything
since everything is added to no-clean-files.

There is no need to descend to ./Kbuild in the first place.
We can drop the no-clean-files assignment.

With this, there is no more user of no-clean-files. I will keep it
for a while to see whether a new user will appear.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-21 21:03:58 +09:00
Masahiro Yamada
d082402e21 kbuild: remove meaningless 'targets' in ./Kbuild
timeconst.h is generated by $(call filechk,...), missing-syscalls and
old-atomics are invoked by $(call cmd,...)

None of them needs to be added to 'targets'.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-15 02:25:11 +09:00
Masahiro Yamada
d4945049ad kbuild: remove 'make /' support
'make /' is just an alias for 'make ./'; this builds all objects of an
external module, but skips the modpost stage.

I am not a big fan of 'make /' since it looks as if it were touching
the root directory of the system. I like 'make ./' better.

I do not know how many people are using it, but let's show a hint if
it is used. Also, move it close to the external module rules since
this only makes sense for external modules.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-15 02:25:11 +09:00
Masahiro Yamada
c2290f3286 kbuild: fix modkern_aflags implementation
For the single target building %.symtypes from %.S, $(a_flags) is
expanded into the _KERNEL flags even if the object is a part of a
module.

$(real-obj-m:.o=.symtypes): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)

... would fix the issue, but it is not nice to duplicate similar code
for every suffix.

Implement modkern_aflags in the same way as modkern_cflags.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-15 02:25:11 +09:00
Masahiro Yamada
986662b903 kbuild: refactor part-of-module more
Make it even shorter.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-15 02:25:11 +09:00
Masahiro Yamada
16b59cd785 kbuild: move the Module.symvers check for external module build
$(objtree)/Module.symvers is not required for descending into
sub-directories. It is needed for the modpost stage.

Move the Module.symvers check to the right place.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-15 02:25:11 +09:00
Masahiro Yamada
33e84f2e79 kbuild: treat an object as multi-used when $(foo-) is set
Currently, Kbuild treats an object as multi-used when any of
$(foo-objs), $(foo-y), $(foo-m) is set. It makes more sense to
check $(foo-) as well.

In the context of foo-$(CONFIG_FOO_FEATURE1), CONFIG_FOO_FEATURE1
could be unset.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-15 02:25:11 +09:00
Masahiro Yamada
f6545bec96 kbuild: add [M] marker for build log of *.mod.o
This builds module objects, so [M] makes sense.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-14 01:10:42 +09:00