1. Add default ISA level selection in non-multiarch/rtld
implementations.
2. Add ISA level build guards to different implementations.
- I.e strcmp-avx2.S which is ISA level 3 will only build if
compiled ISA level <= 3. Otherwise there is no reason to
include it as we will always use one of the ISA level 4
implementations (strcmp-evex.S).
3. Refactor the ifunc selector and ifunc implementation list to use
the ISA level aware wrapper macros that allow functions below the
compiled ISA level (with a guranteed replacement) to be skipped.
Tested with and without multiarch on x86_64 for ISA levels:
{generic, x86-64-v2, x86-64-v3, x86-64-v4}
And m32 with and without multiarch.
This commit doesn't affect libc.so.6, its just housekeeping to prepare
for adding explicit ISA level support.
Tested build on x86_64 and x86_32 with/without multiarch.
I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.
I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah. I don't
know why I run into these diagnostics whereas others evidently do not.
remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
Since strlen.S contains SSE2 version of strlen/strnlen and SSE4.1
version of wcslen/wcsnlen, move strlen.S to multiarch/strlen-vec.S
and include multiarch/strlen-vec.S from SSE2 and SSE4.1 variants.
This also removes the unused symbols, __GI___strlen_sse2 and
__GI___wcsnlen_sse4_1.
I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 6694 files FOO.
I then removed trailing white space from benchtests/bench-pthread-locks.c
and iconvdata/tst-iconv-big5-hkscs-to-2ucs4.c, to work around this
diagnostic from Savannah:
remote: *** pre-commit check failed ...
remote: *** error: lines with trailing whitespace found
remote: error: hook declined to update refs/heads/master
On x32, the size_t parameter may be passed in the lower 32 bits of a
64-bit register with the non-zero upper 32 bits. The string/memory
functions written in assembly can only use the lower 32 bits of a
64-bit register as length or must clear the upper 32 bits before using
the full 64-bit register for length.
This pach fixes strnlen/wcsnlen for x32. Tested on x86-64 and x32. On
x86-64, libc.so is the same with and withou the fix.
[BZ# 24097]
CVE-2019-6488
* sysdeps/x86_64/multiarch/strlen-avx2.S: Use RSI_LP for length.
Clear the upper 32 bits of RSI register.
* sysdeps/x86_64/strlen.S: Use RSI_LP for length.
* sysdeps/x86_64/x32/Makefile (tests): Add tst-size_t-strnlen
and tst-size_t-wcsnlen.
* sysdeps/x86_64/x32/tst-size_t-strnlen.c: New file.
* sysdeps/x86_64/x32/tst-size_t-wcsnlen.c: Likewise.
The difference between strlen and wcslen is byte vs int. We can
replace pminub and pcmpeqb with pminud and pcmpeqd to turn strlen
into wcslen.
* sysdeps/x86_64/strlen.S (PMINU): New.
(PCMPEQ): Likewise.
(SHIFT_RETURN): Likewise.
(FIND_ZERO): Replace pcmpeqb with PCMPEQ.
(strlen): Add SHIFT_RETURN before ret. Replace pcmpeqb and
pminub with PCMPEQ and PMINU.
* sysdeps/x86_64/wcsnlen.S: New file.
Since ld.so preserves vector registers now, we can use %xmm[0-4] to
avoid the REX prefix.
* sysdeps/x86_64/strlen.S: Replace %xmm[8-12] with %xmm[0-4].
* sysdeps/x86_64/dl-machine.h (elf_machine_runtime_setup): Declare
external functions with hidden attribute.
(elf_machine_rela): Optimize.
* sysdeps/x86_64/memset.S: New file.
* sysdeps/x86_64/bzero.S: New file.
* sysdeps/x86_64/stpcpy.S: New file.
* sysdeps/x86_64/strcat.S: New file.
* sysdeps/x86_64/strchr.S: New file.
* sysdeps/x86_64/strcpy.S: New file.
* sysdeps/x86_64/strcspn.S: New file.
* sysdeps/x86_64/strlen.S: New file.
* sysdeps/x86_64/strpbrk.S: New file.
* sysdeps/x86_64/strspn.S: New file.
* sysdeps/x86_64/strcmp.S: New file.
* sysdeps/x86_64/strtok_r.S: New file.
* sysdeps/x86_64/strtok.S: New file.
* sysdeps/x86_64/memcpy.S: New file.
* sysdeps/x86_64/mempcpy.S: New file.
