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  1. 14 9月, 2021 1 次提交
  3. 10 9月, 2021 1 次提交
  5. 09 9月, 2021 7 次提交
  7. 07 9月, 2021 1 次提交
    • L
      lib/test_scanf: split up number parsing test routines · ba7b1f86
      由 Linus Torvalds 提交于 
      It turns out that gcc has real trouble merging all the temporary
on-stack buffer allocation.  So despite the fact that their lifetimes do
not overlap, gcc will allocate stack for all of them when they have
different types.  Which they do in the number scanning test routines.

This is unfortunate in general, but with lots of test-cases in one
function, it becomes a real problem.  gcc will allocate a huge stack
frame for no actual good reason.

We have tried to counteract this tendency of gcc not merging stack slots
(see "-fconserve-stack"), but that has limited effect (and should be on
by default these days, iirc).

So with all the debug options enabled on an i386 allmodconfig build, we
end up with overly big stack frames, and the resulting stack frame size
warnings (now errors):

   lib/test_scanf.c: In function ‘numbers_list_field_width_val_width’:
   lib/test_scanf.c:530:1: error: the frame size of 2088 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]
     530 | }
         | ^
   lib/test_scanf.c: In function ‘numbers_list_field_width_typemax’:
   lib/test_scanf.c:488:1: error: the frame size of 2568 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]
     488 | }
         | ^
   lib/test_scanf.c: In function ‘numbers_list’:
   lib/test_scanf.c:437:1: error: the frame size of 2088 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]
     437 | }
         | ^

In this particular case, the reasonably straightforward solution is to
just split out the test routines into multiple more targeted versions.
That way we don't have one huge stack, but several smaller ones, and
they aren't active all at the same time.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      ba7b1f86
  9. 04 9月, 2021 11 次提交
  11. 03 9月, 2021 1 次提交
    • N
      Makefile: remove stale cc-option checks · 7d73c3e9
      由 Nick Desaulniers 提交于 
      cc-option, cc-option-yn, and cc-disable-warning all invoke the compiler
during build time, and can slow down the build when these checks become
stale for our supported compilers, whose minimally supported versions
increases over time. See Documentation/process/changes.rst for the
current supported minimal versions (GCC 4.9+, clang 10.0.1+). Compiler
version support for these flags may be verified on godbolt.org.

The following flags are GCC only and supported since at least GCC 4.9.
Remove cc-option and cc-disable-warning tests.
* -fno-tree-loop-im
* -Wno-maybe-uninitialized
* -fno-reorder-blocks
* -fno-ipa-cp-clone
* -fno-partial-inlining
* -femit-struct-debug-baseonly
* -fno-inline-functions-called-once
* -fconserve-stack

The following flags are supported by all supported versions of GCC and
Clang. Remove their cc-option, cc-option-yn, and cc-disable-warning tests.
* -fno-delete-null-pointer-checks
* -fno-var-tracking
* -Wno-array-bounds

The following configs are made dependent on GCC, since they use GCC
specific flags.
* READABLE_ASM
* DEBUG_SECTION_MISMATCH

-mfentry was not supported by s390-linux-gnu-gcc until gcc-9+, add a
comment.

--param=allow-store-data-races=0 was renamed to -fno-allow-store-data-races
in the GCC 10 release; add a comment.

-Wmaybe-uninitialized (GCC specific) was being added for CONFIG_GCOV,
then again unconditionally; add it only once.

Also, base RETPOLINE_CFLAGS and RETPOLINE_VDSO_CFLAGS on CONFIC_CC_IS_*
then remove cc-option tests for Clang.

Link: https://github.com/ClangBuiltLinux/linux/issues/1436Acked-by: NMiguel Ojeda <ojeda@kernel.org>
Reviewed-by: NNathan Chancellor <nathan@kernel.org>
Signed-off-by: NNick Desaulniers <ndesaulniers@google.com>
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>
      7d73c3e9
  13. 30 8月, 2021 2 次提交
    • L
      string: improve default out-of-line memcmp() implementation · 291d47cc
      由 Linus Torvalds 提交于 
      This just does the "if the architecture does efficient unaligned
handling, start the memcmp using 'unsigned long' accesses", since
Nikolay Borisov found a load that cares.

This is basically the minimal patch, and limited to architectures that
are known to not have slow unaligned handling.  We've had the stupid
byte-at-a-time version forever, and nobody has ever even noticed before,
so let's keep the fix minimal.

A potential further improvement would be to align one of the sources in
order to at least minimize unaligned cases, but the only real case of
bigger memcmp() users seems to be the FIDEDUPERANGE ioctl().  As David
Sterba says, the dedupe ioctl is typically called on ranges spanning
many pages so the common case will all be page-aligned anyway.

All the relevant architectures select HAVE_EFFICIENT_UNALIGNED_ACCESS,
so I'm not going to worry about the combination of a very rare use-case
and a rare architecture until somebody actually hits it.  Particularly
since Nikolay also tested the more complex patch with extra alignment
handling code, and it only added overhead.

Link: https://lore.kernel.org/lkml/20210721135926.602840-1-nborisov@suse.com/Reported-by: NNikolay Borisov <nborisov@suse.com>
Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      291d47cc
    • H
      parisc: Increase size of gcc stack frame check · 55b70eed
      由 Helge Deller 提交于 
      parisc uses much bigger frames than other architectures, so increase the
stack frame check value to avoid compiler warnings.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Abd-Alrhman Masalkhi <abd.masalkhi@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: NHelge Deller <deller@gmx.de>
      55b70eed
  15. 27 8月, 2021 1 次提交
  17. 25 8月, 2021 2 次提交
  19. 24 8月, 2021 1 次提交
  21. 22 8月, 2021 2 次提交
  23. 21 8月, 2021 1 次提交
  25. 19 8月, 2021 1 次提交
  27. 18 8月, 2021 3 次提交
  29. 17 8月, 2021 2 次提交
  31. 14 8月, 2021 3 次提交