1a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org// Copyright 2010 the V8 project authors. All rights reserved. 23484964a86451e86dcf04be9bd8c0d76ee04f081rossberg@chromium.org// Use of this source code is governed by a BSD-style license that can be 33484964a86451e86dcf04be9bd8c0d76ee04f081rossberg@chromium.org// found in the LICENSE file. 4a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org 5a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org// This module gets enough CPU information to optimize the 6a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org// atomicops module on x86. 7a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org 8a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org#include <string.h> 9a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org 101e2d50cf3d94ff48285da107b7a9da1ad0fc873dmachenbach@chromium.org#include "src/base/atomicops.h" 11a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org 12a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org// This file only makes sense with atomicops_internals_x86_gcc.h -- it 13a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org// depends on structs that are defined in that file. If atomicops.h 14a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org// doesn't sub-include that file, then we aren't needed, and shouldn't 15a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org// try to do anything. 161e2d50cf3d94ff48285da107b7a9da1ad0fc873dmachenbach@chromium.org#ifdef V8_BASE_ATOMICOPS_INTERNALS_X86_GCC_H_ 17a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org 18a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org// Inline cpuid instruction. In PIC compilations, %ebx contains the address 19a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org// of the global offset table. To avoid breaking such executables, this code 20a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org// must preserve that register's value across cpuid instructions. 21a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org#if defined(__i386__) 22a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org#define cpuid(a, b, c, d, inp) \ 23a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org asm("mov %%ebx, %%edi\n" \ 24a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org "cpuid\n" \ 25a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org "xchg %%edi, %%ebx\n" \ 26a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org : "=a" (a), "=D" (b), "=c" (c), "=d" (d) : "a" (inp)) 27a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org#elif defined(__x86_64__) 28a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org#define cpuid(a, b, c, d, inp) \ 29a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org asm("mov %%rbx, %%rdi\n" \ 30a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org "cpuid\n" \ 31a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org "xchg %%rdi, %%rbx\n" \ 32a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org : "=a" (a), "=D" (b), "=c" (c), "=d" (d) : "a" (inp)) 33a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org#endif 34a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org 35a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org#if defined(cpuid) // initialize the struct only on x86 36a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org 378e8294a88dc7d58f579aee0ba08c19fc8a616e2dsgjesse@chromium.orgnamespace v8 { 381e2d50cf3d94ff48285da107b7a9da1ad0fc873dmachenbach@chromium.orgnamespace base { 398e8294a88dc7d58f579aee0ba08c19fc8a616e2dsgjesse@chromium.org 40a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org// Set the flags so that code will run correctly and conservatively, so even 41a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org// if we haven't been initialized yet, we're probably single threaded, and our 42a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org// default values should hopefully be pretty safe. 43a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.orgstruct AtomicOps_x86CPUFeatureStruct AtomicOps_Internalx86CPUFeatures = { 44a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org false, // bug can't exist before process spawns multiple threads 45975b940441085887fc02bebf8877d5ec97e1e06cmachenbach@chromium.org#if !defined(__SSE2__) 46975b940441085887fc02bebf8877d5ec97e1e06cmachenbach@chromium.org false, // no SSE2 47975b940441085887fc02bebf8877d5ec97e1e06cmachenbach@chromium.org#endif 48a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org}; 49a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org 501e2d50cf3d94ff48285da107b7a9da1ad0fc873dmachenbach@chromium.org} } // namespace v8::base 518e8294a88dc7d58f579aee0ba08c19fc8a616e2dsgjesse@chromium.org 528e8294a88dc7d58f579aee0ba08c19fc8a616e2dsgjesse@chromium.orgnamespace { 538e8294a88dc7d58f579aee0ba08c19fc8a616e2dsgjesse@chromium.org 54a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org// Initialize the AtomicOps_Internalx86CPUFeatures struct. 558e8294a88dc7d58f579aee0ba08c19fc8a616e2dsgjesse@chromium.orgvoid AtomicOps_Internalx86CPUFeaturesInit() { 561e2d50cf3d94ff48285da107b7a9da1ad0fc873dmachenbach@chromium.org using v8::base::AtomicOps_Internalx86CPUFeatures; 578e8294a88dc7d58f579aee0ba08c19fc8a616e2dsgjesse@chromium.org 58ed1a63112185152bc10fbd02418393804a5fcf04machenbach@chromium.org uint32_t eax = 0; 59ed1a63112185152bc10fbd02418393804a5fcf04machenbach@chromium.org uint32_t ebx = 0; 60ed1a63112185152bc10fbd02418393804a5fcf04machenbach@chromium.org uint32_t ecx = 0; 61ed1a63112185152bc10fbd02418393804a5fcf04machenbach@chromium.org uint32_t edx = 0; 62a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org 63a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org // Get vendor string (issue CPUID with eax = 0) 64a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org cpuid(eax, ebx, ecx, edx, 0); 65a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org char vendor[13]; 66d06b9264b1c886fc80a100e9915cf8ae07fdb4e5machenbach@chromium.org memcpy(vendor, &ebx, 4); 67d06b9264b1c886fc80a100e9915cf8ae07fdb4e5machenbach@chromium.org memcpy(vendor + 4, &edx, 4); 68d06b9264b1c886fc80a100e9915cf8ae07fdb4e5machenbach@chromium.org memcpy(vendor + 8, &ecx, 4); 69a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org vendor[12] = 0; 70a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org 71a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org // get feature flags in ecx/edx, and family/model in eax 72a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org cpuid(eax, ebx, ecx, edx, 1); 73a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org 74a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org int family = (eax >> 8) & 0xf; // family and model fields 75a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org int model = (eax >> 4) & 0xf; 76a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org if (family == 0xf) { // use extended family and model fields 77a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org family += (eax >> 20) & 0xff; 78a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org model += ((eax >> 16) & 0xf) << 4; 79a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org } 80a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org 81a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org // Opteron Rev E has a bug in which on very rare occasions a locked 82a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org // instruction doesn't act as a read-acquire barrier if followed by a 83a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org // non-locked read-modify-write instruction. Rev F has this bug in 84a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org // pre-release versions, but not in versions released to customers, 85a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org // so we test only for Rev E, which is family 15, model 32..63 inclusive. 86a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org if (strcmp(vendor, "AuthenticAMD") == 0 && // AMD 87a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org family == 15 && 88a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org 32 <= model && model <= 63) { 89a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org AtomicOps_Internalx86CPUFeatures.has_amd_lock_mb_bug = true; 90a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org } else { 91a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org AtomicOps_Internalx86CPUFeatures.has_amd_lock_mb_bug = false; 92a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org } 93975b940441085887fc02bebf8877d5ec97e1e06cmachenbach@chromium.org 94975b940441085887fc02bebf8877d5ec97e1e06cmachenbach@chromium.org#if !defined(__SSE2__) 95975b940441085887fc02bebf8877d5ec97e1e06cmachenbach@chromium.org // edx bit 26 is SSE2 which we use to tell use whether we can use mfence 96975b940441085887fc02bebf8877d5ec97e1e06cmachenbach@chromium.org AtomicOps_Internalx86CPUFeatures.has_sse2 = ((edx >> 26) & 1); 97975b940441085887fc02bebf8877d5ec97e1e06cmachenbach@chromium.org#endif 98a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org} 99a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org 100a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.orgclass AtomicOpsx86Initializer { 101a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org public: 102a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org AtomicOpsx86Initializer() { 103a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org AtomicOps_Internalx86CPUFeaturesInit(); 104a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org } 105a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org}; 106a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org 107e0e1b0d3e70c933d36ed381d511e9fda39f2a751mstarzinger@chromium.org 108a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org// A global to get use initialized on startup via static initialization :/ 109a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.orgAtomicOpsx86Initializer g_initer; 110a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org 111a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org} // namespace 112a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org 113a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org#endif // if x86 114a55512615f5adc085d23bc8589d155c4b579fb7bkasperl@chromium.org 1151e2d50cf3d94ff48285da107b7a9da1ad0fc873dmachenbach@chromium.org#endif // ifdef V8_BASE_ATOMICOPS_INTERNALS_X86_GCC_H_ 116