Previous implementation was adjusting length (rsi) to match
bytes (eax), but since there is no bound to length this can cause
overflow.

Fix is to just convert the byte-count (eax) to length by dividing by
sizeof (wchar_t) before the comparison.

Full check passes on x86-64 and build succeeds w/ and w/o multiarch.

(cherry picked from commit b0969fa53a28b4ab2159806bf6c99a98999502ee)

This commit fixes the bug mentioned in the previous commit.

The previous implementations of wmemchr in these files relied
on maxlen * sizeof(wchar_t) which was not guranteed by the standard.

The new overflow tests added in the previous commit now
pass (As well as all the other tests).

Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com>
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit a775a7a3eb1e85b54af0b4ee5ff4dcf66772a1fb)

No bug. This commit optimizes strlen-avx2.S. The optimizations are
mostly small things but they add up to roughly 10-30% performance
improvement for strlen. The results for strnlen are bit more
ambiguous. test-strlen, test-strnlen, test-wcslen, and test-wcsnlen
are all passing.

Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com>
(cherry picked from commit aaa23c35071537e2dcf5807e956802ed215210aa)

Since VZEROUPPER triggers RTM abort while VZEROALL won't, select AVX
optimized string/memory functions with

	xtest
	jz	1f
	vzeroall
	ret
1:
	vzeroupper
	ret

at function exit on processors with usable RTM, but without 256-bit EVEX
instructions to avoid VZEROUPPER inside a transactionally executing RTM
region.

(cherry picked from commit 7ebba91361badf7531d4e75050627a88d424872f)

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.

	* All files with FSF copyright notices: Update copyright dates
	using scripts/update-copyrights.
	* locale/programs/charmap-kw.h: Regenerated.
	* locale/programs/locfile-kw.h: Likewise.

Since the result of testl is never used, this patch removes it.

Tested on 64-bit AVX2 machine.

	* sysdeps/x86_64/multiarch/strlen-avx2.S (STRLEN): Remove the
	unnecessary testl.

	* All files with FSF copyright notices: Update copyright dates
	using scripts/update-copyrights.
	* locale/programs/charmap-kw.h: Regenerated.
	* locale/programs/locfile-kw.h: Likewise.

Optimize strlen/strnlen/wcslen/wcsnlen with AVX2 to check 32 bytes with
a single vector compare instruction.  It is as fast as SSE2 versions for
size <= 16 bytes and up to 1X faster for or size > 16 bytes on Haswell.
Select AVX2 version on AVX2 machines where vzeroupper is preferred and
AVX unaligned load is fast.

NB: It uses TZCNT instead of BSF since TZCNT produces the same result
as BSF for non-zero input.  TZCNT is faster than BSF and is executed
as BSF if machine doesn't support TZCNT.

	* sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add
	strlen-sse2, strnlen-sse2, strlen-avx2, strnlen-avx2,
	wcslen-sse2, wcslen-avx2 and wcsnlen-avx2.
	* sysdeps/x86_64/multiarch/ifunc-impl-list.c
	(__libc_ifunc_impl_list): Add tests for __strlen_avx2,
	__strlen_sse2, __strnlen_avx2, __strnlen_sse2, __wcslen_avx2,
	__wcslen_sse2 and __wcsnlen_avx2.
	* sysdeps/x86_64/multiarch/strlen-avx2.S: New file.
	* sysdeps/x86_64/multiarch/strlen-sse2.S: Likewise.
	* sysdeps/x86_64/multiarch/strlen.c: Likewise.
	* sysdeps/x86_64/multiarch/strnlen-avx2.S: Likewise.
	* sysdeps/x86_64/multiarch/strnlen-sse2.S: Likewise.
	* sysdeps/x86_64/multiarch/strnlen.c: Likewise.
	* sysdeps/x86_64/multiarch/wcslen-avx2.S: Likewise.
	* sysdeps/x86_64/multiarch/wcslen-sse2.S: Likewise.
	* sysdeps/x86_64/multiarch/wcslen.c: Likewise.
	* sysdeps/x86_64/multiarch/wcsnlen-avx2.S: Likewise.
	* sysdeps/x86_64/multiarch/wcsnlen.c (OPTIMIZE (avx2)): New.
	(IFUNC_SELECTOR): Return OPTIMIZE (avx2) on AVX2 machines where
	vzeroupper is preferred and AVX unaligned load is fast.