ref: 2bbc75bddc6f2a07056ff017108e35f14061041b
dir: /third_party/boringssl/src/crypto/cpu-intel.c/
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
*
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* "This product includes cryptographic software written by
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
* 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
*
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
* [including the GNU Public Licence.] */
#include <openssl/cpu.h>
#if !defined(OPENSSL_NO_ASM) && (defined(OPENSSL_X86) || defined(OPENSSL_X86_64))
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#if defined(_MSC_VER)
OPENSSL_MSVC_PRAGMA(warning(push, 3))
#include <immintrin.h>
#include <intrin.h>
OPENSSL_MSVC_PRAGMA(warning(pop))
#endif
#include "internal.h"
// OPENSSL_cpuid runs the cpuid instruction. |leaf| is passed in as EAX and ECX
// is set to zero. It writes EAX, EBX, ECX, and EDX to |*out_eax| through
// |*out_edx|.
static void OPENSSL_cpuid(uint32_t *out_eax, uint32_t *out_ebx,
uint32_t *out_ecx, uint32_t *out_edx, uint32_t leaf) {
#if defined(_MSC_VER)
int tmp[4];
__cpuid(tmp, (int)leaf);
*out_eax = (uint32_t)tmp[0];
*out_ebx = (uint32_t)tmp[1];
*out_ecx = (uint32_t)tmp[2];
*out_edx = (uint32_t)tmp[3];
#elif defined(__pic__) && defined(OPENSSL_32_BIT)
// Inline assembly may not clobber the PIC register. For 32-bit, this is EBX.
// See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47602.
__asm__ volatile (
"xor %%ecx, %%ecx\n"
"mov %%ebx, %%edi\n"
"cpuid\n"
"xchg %%edi, %%ebx\n"
: "=a"(*out_eax), "=D"(*out_ebx), "=c"(*out_ecx), "=d"(*out_edx)
: "a"(leaf)
);
#else
__asm__ volatile (
"xor %%ecx, %%ecx\n"
"cpuid\n"
: "=a"(*out_eax), "=b"(*out_ebx), "=c"(*out_ecx), "=d"(*out_edx)
: "a"(leaf)
);
#endif
}
// OPENSSL_xgetbv returns the value of an Intel Extended Control Register (XCR).
// Currently only XCR0 is defined by Intel so |xcr| should always be zero.
static uint64_t OPENSSL_xgetbv(uint32_t xcr) {
#if defined(_MSC_VER)
return (uint64_t)_xgetbv(xcr);
#else
uint32_t eax, edx;
__asm__ volatile ("xgetbv" : "=a"(eax), "=d"(edx) : "c"(xcr));
return (((uint64_t)edx) << 32) | eax;
#endif
}
// handle_cpu_env applies the value from |in| to the CPUID values in |out[0]|
// and |out[1]|. See the comment in |OPENSSL_cpuid_setup| about this.
static void handle_cpu_env(uint32_t *out, const char *in) {
const int invert = in[0] == '~';
const int or = in[0] == '|';
const int skip_first_byte = invert || or;
const int hex = in[skip_first_byte] == '0' && in[skip_first_byte+1] == 'x';
int sscanf_result;
uint64_t v;
if (hex) {
sscanf_result = sscanf(in + invert + 2, "%" PRIx64, &v);
} else {
sscanf_result = sscanf(in + invert, "%" PRIu64, &v);
}
if (!sscanf_result) {
return;
}
if (invert) {
out[0] &= ~v;
out[1] &= ~(v >> 32);
} else if (or) {
out[0] |= v;
out[1] |= (v >> 32);
} else {
out[0] = v;
out[1] = v >> 32;
}
}
void OPENSSL_cpuid_setup(void) {
// Determine the vendor and maximum input value.
uint32_t eax, ebx, ecx, edx;
OPENSSL_cpuid(&eax, &ebx, &ecx, &edx, 0);
uint32_t num_ids = eax;
int is_intel = ebx == 0x756e6547 /* Genu */ &&
edx == 0x49656e69 /* ineI */ &&
ecx == 0x6c65746e /* ntel */;
int is_amd = ebx == 0x68747541 /* Auth */ &&
edx == 0x69746e65 /* enti */ &&
ecx == 0x444d4163 /* cAMD */;
uint32_t extended_features[2] = {0};
if (num_ids >= 7) {
OPENSSL_cpuid(&eax, &ebx, &ecx, &edx, 7);
extended_features[0] = ebx;
extended_features[1] = ecx;
}
OPENSSL_cpuid(&eax, &ebx, &ecx, &edx, 1);
if (is_amd) {
// See https://www.amd.com/system/files/TechDocs/25481.pdf, page 10.
const uint32_t base_family = (eax >> 8) & 15;
const uint32_t base_model = (eax >> 4) & 15;
uint32_t family = base_family;
uint32_t model = base_model;
if (base_family == 0xf) {
const uint32_t ext_family = (eax >> 20) & 255;
family += ext_family;
const uint32_t ext_model = (eax >> 16) & 15;
model |= ext_model << 4;
}
if (family < 0x17 || (family == 0x17 && 0x70 <= model && model <= 0x7f)) {
// Disable RDRAND on AMD families before 0x17 (Zen) due to reported
// failures after suspend.
// https://bugzilla.redhat.com/show_bug.cgi?id=1150286
// Also disable for family 0x17, models 0x70–0x7f, due to possible RDRAND
// failures there too.
ecx &= ~(1u << 30);
}
}
// Force the hyper-threading bit so that the more conservative path is always
// chosen.
edx |= 1u << 28;
// Reserved bit #20 was historically repurposed to control the in-memory
// representation of RC4 state. Always set it to zero.
edx &= ~(1u << 20);
// Reserved bit #30 is repurposed to signal an Intel CPU.
if (is_intel) {
edx |= (1u << 30);
// Clear the XSAVE bit on Knights Landing to mimic Silvermont. This enables
// some Silvermont-specific codepaths which perform better. See OpenSSL
// commit 64d92d74985ebb3d0be58a9718f9e080a14a8e7f.
if ((eax & 0x0fff0ff0) == 0x00050670 /* Knights Landing */ ||
(eax & 0x0fff0ff0) == 0x00080650 /* Knights Mill (per SDE) */) {
ecx &= ~(1u << 26);
}
} else {
edx &= ~(1u << 30);
}
// 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)) {
// XCR0 may only be queried if the OSXSAVE bit is set.
xcr0 = OPENSSL_xgetbv(0);
}
// See Intel manual, volume 1, section 14.3.
if ((xcr0 & 6) != 6) {
// YMM registers cannot be used.
ecx &= ~(1u << 28); // AVX
ecx &= ~(1u << 12); // FMA
ecx &= ~(1u << 11); // AMD XOP
// Clear AVX2 and AVX512* bits.
//
// TODO(davidben): Should bits 17 and 26-28 also be cleared? Upstream
// doesn't clear those.
extended_features[0] &=
~((1u << 5) | (1u << 16) | (1u << 21) | (1u << 30) | (1u << 31));
}
// See Intel manual, volume 1, section 15.2.
if ((xcr0 & 0xe6) != 0xe6) {
// Clear AVX512F. Note we don't touch other AVX512 extensions because they
// can be used with YMM.
extended_features[0] &= ~(1u << 16);
}
// Disable ADX instructions on Knights Landing. See OpenSSL commit
// 64d92d74985ebb3d0be58a9718f9e080a14a8e7f.
if ((ecx & (1u << 26)) == 0) {
extended_features[0] &= ~(1u << 19);
}
OPENSSL_ia32cap_P[0] = edx;
OPENSSL_ia32cap_P[1] = ecx;
OPENSSL_ia32cap_P[2] = extended_features[0];
OPENSSL_ia32cap_P[3] = extended_features[1];
const char *env1, *env2;
env1 = getenv("OPENSSL_ia32cap");
if (env1 == NULL) {
return;
}
// OPENSSL_ia32cap can contain zero, one or two values, separated with a ':'.
// Each value is a 64-bit, unsigned value which may start with "0x" to
// indicate a hex value. Prior to the 64-bit value, a '~' or '|' may be given.
//
// If the '~' prefix is present:
// the value is inverted and ANDed with the probed CPUID result
// If the '|' prefix is present:
// the value is ORed with the probed CPUID result
// Otherwise:
// the value is taken as the result of the CPUID
//
// The first value determines OPENSSL_ia32cap_P[0] and [1]. The second [2]
// and [3].
handle_cpu_env(&OPENSSL_ia32cap_P[0], env1);
env2 = strchr(env1, ':');
if (env2 != NULL) {
handle_cpu_env(&OPENSSL_ia32cap_P[2], env2 + 1);
}
}
#endif // !OPENSSL_NO_ASM && (OPENSSL_X86 || OPENSSL_X86_64)