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Fix check for AVX enablement

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The AVX bit is set if the CPU supports AVX.  But this doesn't mean the
kernel does.  Add checks according to Intel's documentation.
This commit is contained in:
Ulrich Drepper 2011-07-20 21:21:03 -04:00
parent 6986b98a18
commit 5644ef5461
5 changed files with 58 additions and 16 deletions
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9
ChangeLog
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@ -1,6 +1,13 @@
2011-07-20 Ulrich Drepper <drepper@gmail.com>
* sysdeps/x86_64/bits/link.h (La_x86_64_ymm): Force 16-byt alignment.
[BZ #13007]
* sysdeps/x86_64/dl-trampoline.S (_dl_runtime_profile): More complete
check for AVX enablement so that we don't crash with old kernels and
new hardware.
* elf/tst-audit4.c: Add same checks here.
* elf/tst-audit6.c: Likewise.
* sysdeps/x86_64/bits/link.h (La_x86_64_ymm): Force 16-byte alignment.
2011-07-09 Andreas Schwab <schwab@linux-m68k.org>

4
NEWS
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@ -1,4 +1,4 @@
GNU C Library NEWS -- history of user-visible changes. 2011-7-19
GNU C Library NEWS -- history of user-visible changes. 2011-7-20
Copyright (C) 1992-2009, 2010, 2011 Free Software Foundation, Inc.
See the end for copying conditions.
@ -9,7 +9,7 @@ Version 2.15
* The following bugs are resolved with this release:
9696, 12868, 12874, 12885, 12907, 12922, 12935
9696, 12868, 12874, 12885, 12907, 12922, 12935, 13007
* New program pldd to list loaded object of a process
Implemented by Ulrich Drepper.

22
elf/tst-audit4.c
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@ -6,16 +6,30 @@
#include <cpuid.h>
#include <immintrin.h>
static int
avx_enabled (void)
{
unsigned int eax, ebx, ecx, edx;
if (__get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
|| (ecx & (bit_AVX | bit_OSXSAVE)) != (bit_AVX | bit_OSXSAVE))
return 0;
/* Check the OS has AVX and SSE saving enabled. */
asm ("xgetbv" : "=a" (eax), "=d" (edx) : "c" (0));
return (eax & 6) == 6;
}
extern __m256i audit_test (__m256i, __m256i, __m256i, __m256i,
__m256i, __m256i, __m256i, __m256i);
int
main (void)
{
unsigned int eax, ebx, ecx, edx;
/* Run AVX test only if AVX is supported. */
if (__get_cpuid (1, &eax, &ebx, &ecx, &edx)
&& (ecx & bit_AVX))
if (avx_enabled ())
{
__m256i ymm = _mm256_setzero_si256 ();
__m256i ret = audit_test (ymm, ymm, ymm, ymm, ymm, ymm, ymm, ymm);

22
elf/tst-audit6.c
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@ -8,14 +8,28 @@
extern __m128i audit_test (__m128i, __m128i, __m128i, __m128i,
__m128i, __m128i, __m128i, __m128i);
int
main (void)
static int
avx_enabled (void)
{
unsigned int eax, ebx, ecx, edx;
if (__get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
|| (ecx & (bit_AVX | bit_OSXSAVE)) != (bit_AVX | bit_OSXSAVE))
return 0;
/* Check the OS has AVX and SSE saving enabled. */
asm ("xgetbv" : "=a" (eax), "=d" (edx) : "c" (0));
return (eax & 6) == 6;
}
int
main (void)
{
/* Run AVX test only if AVX is supported. */
if (__get_cpuid (1, &eax, &ebx, &ecx, &edx)
&& (ecx & bit_AVX))
if (avx_enabled ())
{
__m128i xmm = _mm_setzero_si128 ();
__m128i ret = audit_test (xmm, xmm, xmm, xmm, xmm, xmm, xmm, xmm);

17
sysdeps/x86_64/dl-trampoline.S
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@ -1,5 +1,5 @@
/* PLT trampolines. x86-64 version.
Copyright (C) 2004, 2005, 2007, 2009 Free Software Foundation, Inc.
Copyright (C) 2004, 2005, 2007, 2009, 2011 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
@ -139,10 +139,17 @@ L(have_avx):
movl $1, %eax
cpuid
movq %r11,%rbx # Restore rbx
movl $1, %eax
testl $(1 << 28), %ecx
jne 2f
negl %eax
xorl %eax, %eax
// AVX and XSAVE supported?
testl $((1 << 28) | (1 << 27)), %ecx
je 2f
xorl %ecx, %ecx
// Get XFEATURE_ENABLED_MASK
xgetbv
andl $0x6, %eax
cmpl $0x6, %eax
// Nonzero if SSE and AVX state saving is enabled.
sete %al
2: movl %eax, L(have_avx)(%rip)
cmpl $0, %eax