Commit Graph

21 Commits

Author SHA1 Message Date
Heiko Carstens
cada938a01 s390: fix various typos
Fix various typos found with codespell.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2023-07-03 11:19:42 +02:00
Vasily Gorbik
4efd417f29 s390: raise minimum supported machine generation to z10
Machine generations up to z9 (released in May 2006) have been officially
out of service for several years now (z9 end of service - January 31, 2019).
No distributions build kernels supporting those old machine generations
anymore, except Debian, which seems to pick the oldest supported
generation. The team supporting Debian on s390 has been notified about
the change.

Raising minimum supported machine generation to z10 helps to reduce
maintenance cost and effectively remove code, which is not getting
enough testing coverage due to lack of older hardware and distributions
support. Besides that this unblocks some optimization opportunities and
allows to use wider instruction set in asm files for future features
implementation. Due to this change spectre mitigation and usercopy
implementations could be drastically simplified and many newer instructions
could be converted from ".insn" encoding to instruction names.

Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2022-03-10 15:58:17 +01:00
Vasily Gorbik
2268169c14 s390: remove unused expoline to BC instructions
This reverts commit 6deaa3bbca ("s390: extend expoline to BC
instructions"). Expolines to BC instructions were added to be utilized
by commit de5cb6eb51 ("s390: use expoline thunks in the BPF JIT"). But
corresponding code has been removed by commit e1cf4befa2 ("bpf, s390x:
remove ld_abs/ld_ind"). And compiler does not generate such expolines as
well.

Compared to regular expolines, expolines to BC instructions contain
displacement and all possible variations cannot be generated in advance,
making kpatch support more complicated. So, remove those to avoid
future usages.

Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2022-03-08 00:33:01 +01:00
Sven Schnelle
5d17d4ed7e s390: introduce nospec_uses_trampoline()
and replace all of the "__is_defined(CC_USING_EXPOLINE) && !nospec_disable"
occurrences.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-10-26 15:21:29 +02:00
Kees Cook
c74d3c182a s390/speculation: Use statically initialized const for instructions
In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memcpy(), memmove(), and memset(), avoid
confusing the checks when using a static const source.

Move the static const array into a variable so the compiler can perform
appropriate bounds checking.

Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210616201823.1245603-1-keescook@chromium.org
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-06-28 11:18:28 +02:00
Sven Schnelle
17e89e1340 s390/facilities: move stfl information from lowcore to global data
With gcc-11, there are a lot of warnings because the facility functions
are accessing lowcore through a null pointer. Fix this by moving the
facility arrays away from lowcore.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-06-07 17:06:58 +02:00
Linus Torvalds
14be4c61c2 s390 updates for the 5.2 merge window
- Support for kernel address space layout randomization
 
  - Add support for kernel image signature verification
 
  - Convert s390 to the generic get_user_pages_fast code
 
  - Convert s390 to the stack unwind API analog to x86
 
  - Add support for CPU directed interrupts for PCI devices
 
  - Provide support for MIO instructions to the PCI base layer, this
    will allow the use of direct PCI mappings in user space code
 
  - Add the basic KVM guest ultravisor interface for protected VMs
 
  - Add AT_HWCAP bits for several new hardware capabilities
 
  - Update the CPU measurement facility counter definitions to SVN 6
 
  - Arnds cleanup patches for his quest to get LLVM compiles working
 
  - A vfio-ccw update with bug fixes and support for halt and clear
 
  - Improvements for the hardware TRNG code
 
  - Another round of cleanup for the QDIO layer
 
  - Numerous cleanups and bug fixes
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v2
 
 iQEcBAABCAAGBQJc0CCEAAoJEDjwexyKj9rgjmkH/A3e2drvuP/hSF3xfCKTQFdx
 /PoLHQVCqENB3HU3FA/ljoXuG6jMgwj61looqlxBNumXFpIfTg0E1JC5S4wRGJ+K
 cOVhIKV53gcuZkRcCJQp0WMnGzpk1Daf7iYXYmAl+7e+mREUPxOuJ0Ei6vXvRGZS
 8cQrUCGrtPgkAeLlndypHI2M2TDDGJIMczOGbOZau8+8Lo7Wq9zt5y0h/v0ew37g
 ogA0eGh6koU1435dt2pclZRiZ1XOcar3Uin9ioT+RnSgJ4pr1Pza/F6IGO0RdQa+
 rva990lqGFp5r9lE4rMCwK9LWb/rfHdVPd35t9XPwphnQ/ORoWUwLk3uc5XOHow=
 =dbuy
 -----END PGP SIGNATURE-----

Merge tag 's390-5.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 updates from Martin Schwidefsky:

 - Support for kernel address space layout randomization

 - Add support for kernel image signature verification

 - Convert s390 to the generic get_user_pages_fast code

 - Convert s390 to the stack unwind API analog to x86

 - Add support for CPU directed interrupts for PCI devices

 - Provide support for MIO instructions to the PCI base layer, this will
   allow the use of direct PCI mappings in user space code

 - Add the basic KVM guest ultravisor interface for protected VMs

 - Add AT_HWCAP bits for several new hardware capabilities

 - Update the CPU measurement facility counter definitions to SVN 6

 - Arnds cleanup patches for his quest to get LLVM compiles working

 - A vfio-ccw update with bug fixes and support for halt and clear

 - Improvements for the hardware TRNG code

 - Another round of cleanup for the QDIO layer

 - Numerous cleanups and bug fixes

* tag 's390-5.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (98 commits)
  s390/vdso: drop unnecessary cc-ldoption
  s390: fix clang -Wpointer-sign warnigns in boot code
  s390: drop CONFIG_VIRT_TO_BUS
  s390: boot, purgatory: pass $(CLANG_FLAGS) where needed
  s390: only build for new CPUs with clang
  s390: simplify disabled_wait
  s390/ftrace: use HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
  s390/unwind: introduce stack unwind API
  s390/opcodes: add missing instructions to the disassembler
  s390/bug: add entry size to the __bug_table section
  s390: use proper expoline sections for .dma code
  s390/nospec: rename assembler generated expoline thunks
  s390: add missing ENDPROC statements to assembler functions
  locking/lockdep: check for freed initmem in static_obj()
  s390/kernel: add support for kernel address space layout randomization (KASLR)
  s390/kernel: introduce .dma sections
  s390/sclp: do not use static sccbs
  s390/kprobes: use static buffer for insn_page
  s390/kernel: convert SYSCALL and PGM_CHECK handlers to .quad
  s390/kernel: build a relocatable kernel
  ...
2019-05-06 16:42:54 -07:00
Josh Poimboeuf
0336e04a65 s390/speculation: Support 'mitigations=' cmdline option
Configure s390 runtime CPU speculation bug mitigations in accordance
with the 'mitigations=' cmdline option.  This affects Spectre v1 and
Spectre v2.

The default behavior is unchanged.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jiri Kosina <jkosina@suse.cz> (on x86)
Reviewed-by: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Jon Masters <jcm@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-arch@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Phil Auld <pauld@redhat.com>
Link: https://lkml.kernel.org/r/e4a161805458a5ec88812aac0307ae3908a030fc.1555085500.git.jpoimboe@redhat.com
2019-04-17 21:37:29 +02:00
Joe Perches
475c8e9e89 s390: Convert IS_ENABLED uses to __is_defined
IS_ENABLED should be reserved for CONFIG_<FOO> uses so convert
the uses of IS_ENABLED with a #define to __is_defined.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-04-11 13:36:53 +02:00
Martin Schwidefsky
aeaf7002a7 s390: detect etoken facility
Detect and report the etoken facility. With spectre_v2=auto or
CONFIG_EXPOLINE_AUTO=y automatically disable expolines and use
the full branch prediction mode for the kernel.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-07-18 08:32:17 +02:00
Martin Schwidefsky
b7e7f5051b s390: remove closung punctuation from spectre messages
There should not be a '.' at the end of the spectre syslog messages.
Remove them.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-05-09 10:55:01 +02:00
Martin Schwidefsky
6deaa3bbca s390: extend expoline to BC instructions
The BPF JIT uses a 'b <disp>(%r<x>)' instruction in the definition
of the sk_load_word and sk_load_half functions.

Add support for branch-on-condition instructions contained in the
thunk code of an expoline.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-05-07 21:12:42 +02:00
Martin Schwidefsky
4253b0e062 s390: move spectre sysfs attribute code
The nospec-branch.c file is compiled without the gcc options to
generate expoline thunks. The return branch of the sysfs show
functions cpu_show_spectre_v1 and cpu_show_spectre_v2 is an indirect
branch as well. These need to be compiled with expolines.

Move the sysfs functions for spectre reporting to a separate file
and loose an '.' for one of the messages.

Cc: stable@vger.kernel.org # 4.16
Fixes: d424986f1d ("s390: add sysfs attributes for spectre")
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-05-07 21:12:41 +02:00
Sebastian Ott
232acdff21 s390/nospec: include cpu.h
Fix the following sparse warnings:
symbol 'cpu_show_spectre_v1' was not declared. Should it be static?
symbol 'cpu_show_spectre_v2' was not declared. Should it be static?

Signed-off-by: Sebastian Ott <sebott@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-04-16 09:10:23 +02:00
Martin Schwidefsky
6a3d1e81a4 s390: correct nospec auto detection init order
With CONFIG_EXPOLINE_AUTO=y the call of spectre_v2_auto_early() via
early_initcall is done *after* the early_param functions. This
overwrites any settings done with the nobp/no_spectre_v2/spectre_v2
parameters. The code patching for the kernel is done after the
evaluation of the early parameters but before the early_initcall
is done. The end result is a kernel image that is patched correctly
but the kernel modules are not.

Make sure that the nospec auto detection function is called before the
early parameters are evaluated and before the code patching is done.

Fixes: 6e179d6412 ("s390: add automatic detection of the spectre defense")
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-04-11 17:46:00 +02:00
Martin Schwidefsky
d424986f1d s390: add sysfs attributes for spectre
Set CONFIG_GENERIC_CPU_VULNERABILITIES and provide the two functions
cpu_show_spectre_v1 and cpu_show_spectre_v2 to report the spectre
mitigations.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-03-28 08:38:26 +02:00
Martin Schwidefsky
bc03559971 s390: report spectre mitigation via syslog
Add a boot message if either of the spectre defenses is active.
The message is
    "Spectre V2 mitigation: execute trampolines."
or  "Spectre V2 mitigation: limited branch prediction."

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-03-28 08:38:25 +02:00
Martin Schwidefsky
6e179d6412 s390: add automatic detection of the spectre defense
Automatically decide between nobp vs. expolines if the spectre_v2=auto
kernel parameter is specified or CONFIG_EXPOLINE_AUTO=y is set.

The decision made at boot time due to CONFIG_EXPOLINE_AUTO=y being set
can be overruled with the nobp, nospec and spectre_v2 kernel parameters.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-03-28 08:38:24 +02:00
Martin Schwidefsky
b2e2f43a01 s390: move nobp parameter functions to nospec-branch.c
Keep the code for the nobp parameter handling with the code for
expolines. Both are related to the spectre v2 mitigation.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-03-28 08:38:23 +02:00
Eugeniu Rosca
2cb370d615 s390: Replace IS_ENABLED(EXPOLINE_*) with IS_ENABLED(CONFIG_EXPOLINE_*)
I've accidentally stumbled upon the IS_ENABLED(EXPOLINE_*) lines, which
obviously always evaluate to false. Fix this.

Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches")
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-02-19 08:00:06 +01:00
Martin Schwidefsky
f19fbd5ed6 s390: introduce execute-trampolines for branches
Add CONFIG_EXPOLINE to enable the use of the new -mindirect-branch= and
-mfunction_return= compiler options to create a kernel fortified against
the specte v2 attack.

With CONFIG_EXPOLINE=y all indirect branches will be issued with an
execute type instruction. For z10 or newer the EXRL instruction will
be used, for older machines the EX instruction. The typical indirect
call

	basr	%r14,%r1

is replaced with a PC relative call to a new thunk

	brasl	%r14,__s390x_indirect_jump_r1

The thunk contains the EXRL/EX instruction to the indirect branch

__s390x_indirect_jump_r1:
	exrl	0,0f
	j	.
0:	br	%r1

The detour via the execute type instruction has a performance impact.
To get rid of the detour the new kernel parameter "nospectre_v2" and
"spectre_v2=[on,off,auto]" can be used. If the parameter is specified
the kernel and module code will be patched at runtime.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-02-07 15:57:02 +01:00