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Pretend AMD XOP was never a thing.

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It's not clear that any AMD XOP code paths are being properly tested.
AMD dropped XOP starting in Zen.

Here's the one place I found (without looking too hard) where it seems
there is a XOP code path in BoringSSL, in sha512-x86_64.pl. Most of the
other XOP code was removed.

```
$code.=<<___ if ($avx && $SZ==8);
	test	\$`1<<11`,%r10d		# check for XOP
	jnz	.Lxop_shortcut
```

Change-Id: Id3301b2c84648790d010dae546b8e21ece1c528d
Reviewed-on: https://boringssl-review.googlesource.com/c/33405
Reviewed-by: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Adam Langley <agl@google.com>
This commit is contained in:
Brian Smith 2018-11-29 12:54:16 -10:00 committed by CQ bot account: commit-bot@chromium.org
parent e6ad7a027f
commit 36ee9a5a0d
1 changed files with 3 additions and 23 deletions
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24
crypto/cpu-intel.c
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@ -148,23 +148,6 @@ void OPENSSL_cpuid_setup(void) {
int is_intel = ebx == 0x756e6547 /* Genu */ &&
edx == 0x49656e69 /* ineI */ &&
ecx == 0x6c65746e /* ntel */;
int is_amd = ebx == 0x68747541 /* Auth */ &&
edx == 0x69746e65 /* enti */ &&
ecx == 0x444d4163 /* cAMD */;
int has_amd_xop = 0;
if (is_amd) {
// AMD-specific logic.
// See http://developer.amd.com/wordpress/media/2012/10/254811.pdf
OPENSSL_cpuid(&eax, &ebx, &ecx, &edx, 0x80000000);
uint32_t num_extended_ids = eax;
if (num_extended_ids >= 0x80000001) {
OPENSSL_cpuid(&eax, &ebx, &ecx, &edx, 0x80000001);
if (ecx & (1u << 11)) {
has_amd_xop = 1;
}
}
}
uint32_t extended_features[2] = {0};
if (num_ids >= 7) {
@ -198,12 +181,9 @@ void OPENSSL_cpuid_setup(void) {
edx &= ~(1u << 30);
}
// The SDBG bit is repurposed to denote AMD XOP support.
if (has_amd_xop) {
ecx |= (1u << 11);
} else {
// The SDBG bit is repurposed to denote AMD XOP support. Don't ever use AMD
// XOP code paths.
ecx &= ~(1u << 11);
}
uint64_t xcr0 = 0;
if (ecx & (1u << 27)) {