| // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "base/cpu.h" |
| |
| #include <limits.h> |
| #include <stddef.h> |
| #include <stdint.h> |
| #include <string.h> |
| |
| #include <algorithm> |
| #include <utility> |
| |
| #include "base/stl_util.h" |
| #include "build/build_config.h" |
| |
| #if defined(ARCH_CPU_ARM_FAMILY) && (defined(OS_ANDROID) || defined(OS_LINUX)) |
| #include "base/files/file_util.h" |
| #endif |
| |
| #if defined(ARCH_CPU_X86_FAMILY) |
| #if defined(COMPILER_MSVC) |
| #include <intrin.h> |
| #include <immintrin.h> // For _xgetbv() |
| #endif |
| #endif |
| |
| namespace base { |
| |
| CPU::CPU() |
| : signature_(0), |
| type_(0), |
| family_(0), |
| model_(0), |
| stepping_(0), |
| ext_model_(0), |
| ext_family_(0), |
| has_mmx_(false), |
| has_sse_(false), |
| has_sse2_(false), |
| has_sse3_(false), |
| has_ssse3_(false), |
| has_sse41_(false), |
| has_sse42_(false), |
| has_popcnt_(false), |
| has_avx_(false), |
| has_avx2_(false), |
| has_aesni_(false), |
| has_non_stop_time_stamp_counter_(false), |
| is_running_in_vm_(false), |
| cpu_vendor_("unknown") { |
| Initialize(); |
| } |
| |
| namespace { |
| |
| #if defined(ARCH_CPU_X86_FAMILY) |
| #if !defined(COMPILER_MSVC) |
| |
| #if defined(__pic__) && defined(__i386__) |
| |
| void __cpuid(int cpu_info[4], int info_type) { |
| __asm__ volatile( |
| "mov %%ebx, %%edi\n" |
| "cpuid\n" |
| "xchg %%edi, %%ebx\n" |
| : "=a"(cpu_info[0]), "=D"(cpu_info[1]), "=c"(cpu_info[2]), |
| "=d"(cpu_info[3]) |
| : "a"(info_type), "c"(0)); |
| } |
| |
| #else |
| |
| void __cpuid(int cpu_info[4], int info_type) { |
| __asm__ volatile("cpuid\n" |
| : "=a"(cpu_info[0]), "=b"(cpu_info[1]), "=c"(cpu_info[2]), |
| "=d"(cpu_info[3]) |
| : "a"(info_type), "c"(0)); |
| } |
| |
| #endif |
| #endif // !defined(COMPILER_MSVC) |
| |
| // xgetbv returns the value of an Intel Extended Control Register (XCR). |
| // Currently only XCR0 is defined by Intel so |xcr| should always be zero. |
| uint64_t xgetbv(uint32_t xcr) { |
| #if defined(COMPILER_MSVC) |
| return _xgetbv(xcr); |
| #else |
| uint32_t eax, edx; |
| |
| __asm__ volatile ( |
| "xgetbv" : "=a"(eax), "=d"(edx) : "c"(xcr)); |
| return (static_cast<uint64_t>(edx) << 32) | eax; |
| #endif // defined(COMPILER_MSVC) |
| } |
| |
| #endif // ARCH_CPU_X86_FAMILY |
| |
| #if defined(ARCH_CPU_ARM_FAMILY) && (defined(OS_ANDROID) || defined(OS_LINUX)) |
| std::string* CpuInfoBrand() { |
| static std::string* brand = []() { |
| // This function finds the value from /proc/cpuinfo under the key "model |
| // name" or "Processor". "model name" is used in Linux 3.8 and later (3.7 |
| // and later for arm64) and is shown once per CPU. "Processor" is used in |
| // earler versions and is shown only once at the top of /proc/cpuinfo |
| // regardless of the number CPUs. |
| const char kModelNamePrefix[] = "model name\t: "; |
| const char kProcessorPrefix[] = "Processor\t: "; |
| |
| std::string contents; |
| ReadFileToString(FilePath("/proc/cpuinfo"), &contents); |
| DCHECK(!contents.empty()); |
| |
| std::istringstream iss(contents); |
| std::string line; |
| while (std::getline(iss, line)) { |
| if (line.compare(0, strlen(kModelNamePrefix), kModelNamePrefix) == 0) |
| return new std::string(line.substr(strlen(kModelNamePrefix))); |
| if (line.compare(0, strlen(kProcessorPrefix), kProcessorPrefix) == 0) |
| return new std::string(line.substr(strlen(kProcessorPrefix))); |
| } |
| |
| return new std::string(); |
| }(); |
| |
| return brand; |
| } |
| #endif // defined(ARCH_CPU_ARM_FAMILY) && (defined(OS_ANDROID) || |
| // defined(OS_LINUX)) |
| |
| } // namespace |
| |
| void CPU::Initialize() { |
| #if defined(ARCH_CPU_X86_FAMILY) |
| int cpu_info[4] = {-1}; |
| // This array is used to temporarily hold the vendor name and then the brand |
| // name. Thus it has to be big enough for both use cases. There are |
| // static_asserts below for each of the use cases to make sure this array is |
| // big enough. |
| char cpu_string[sizeof(cpu_info) * 3 + 1]; |
| |
| // __cpuid with an InfoType argument of 0 returns the number of |
| // valid Ids in CPUInfo[0] and the CPU identification string in |
| // the other three array elements. The CPU identification string is |
| // not in linear order. The code below arranges the information |
| // in a human readable form. The human readable order is CPUInfo[1] | |
| // CPUInfo[3] | CPUInfo[2]. CPUInfo[2] and CPUInfo[3] are swapped |
| // before using memcpy() to copy these three array elements to |cpu_string|. |
| __cpuid(cpu_info, 0); |
| int num_ids = cpu_info[0]; |
| std::swap(cpu_info[2], cpu_info[3]); |
| static constexpr size_t kVendorNameSize = 3 * sizeof(cpu_info[1]); |
| static_assert(kVendorNameSize < base::size(cpu_string), |
| "cpu_string too small"); |
| memcpy(cpu_string, &cpu_info[1], kVendorNameSize); |
| cpu_string[kVendorNameSize] = '\0'; |
| cpu_vendor_ = cpu_string; |
| |
| // Interpret CPU feature information. |
| if (num_ids > 0) { |
| int cpu_info7[4] = {0}; |
| __cpuid(cpu_info, 1); |
| if (num_ids >= 7) { |
| __cpuid(cpu_info7, 7); |
| } |
| signature_ = cpu_info[0]; |
| stepping_ = cpu_info[0] & 0xf; |
| model_ = ((cpu_info[0] >> 4) & 0xf) + ((cpu_info[0] >> 12) & 0xf0); |
| family_ = (cpu_info[0] >> 8) & 0xf; |
| type_ = (cpu_info[0] >> 12) & 0x3; |
| ext_model_ = (cpu_info[0] >> 16) & 0xf; |
| ext_family_ = (cpu_info[0] >> 20) & 0xff; |
| has_mmx_ = (cpu_info[3] & 0x00800000) != 0; |
| has_sse_ = (cpu_info[3] & 0x02000000) != 0; |
| has_sse2_ = (cpu_info[3] & 0x04000000) != 0; |
| has_sse3_ = (cpu_info[2] & 0x00000001) != 0; |
| has_ssse3_ = (cpu_info[2] & 0x00000200) != 0; |
| has_sse41_ = (cpu_info[2] & 0x00080000) != 0; |
| has_sse42_ = (cpu_info[2] & 0x00100000) != 0; |
| has_popcnt_ = (cpu_info[2] & 0x00800000) != 0; |
| |
| // "Hypervisor Present Bit: Bit 31 of ECX of CPUID leaf 0x1." |
| // See https://lwn.net/Articles/301888/ |
| // This is checking for any hypervisor. Hypervisors may choose not to |
| // announce themselves. Hypervisors trap CPUID and sometimes return |
| // different results to underlying hardware. |
| is_running_in_vm_ = (cpu_info[2] & 0x80000000) != 0; |
| |
| // AVX instructions will generate an illegal instruction exception unless |
| // a) they are supported by the CPU, |
| // b) XSAVE is supported by the CPU and |
| // c) XSAVE is enabled by the kernel. |
| // See http://software.intel.com/en-us/blogs/2011/04/14/is-avx-enabled |
| // |
| // In addition, we have observed some crashes with the xgetbv instruction |
| // even after following Intel's example code. (See crbug.com/375968.) |
| // Because of that, we also test the XSAVE bit because its description in |
| // the CPUID documentation suggests that it signals xgetbv support. |
| has_avx_ = |
| (cpu_info[2] & 0x10000000) != 0 && |
| (cpu_info[2] & 0x04000000) != 0 /* XSAVE */ && |
| (cpu_info[2] & 0x08000000) != 0 /* OSXSAVE */ && |
| (xgetbv(0) & 6) == 6 /* XSAVE enabled by kernel */; |
| has_aesni_ = (cpu_info[2] & 0x02000000) != 0; |
| has_avx2_ = has_avx_ && (cpu_info7[1] & 0x00000020) != 0; |
| } |
| |
| // Get the brand string of the cpu. |
| __cpuid(cpu_info, 0x80000000); |
| const int max_parameter = cpu_info[0]; |
| |
| static constexpr int kParameterStart = 0x80000002; |
| static constexpr int kParameterEnd = 0x80000004; |
| static constexpr int kParameterSize = kParameterEnd - kParameterStart + 1; |
| static_assert(kParameterSize * sizeof(cpu_info) + 1 == base::size(cpu_string), |
| "cpu_string has wrong size"); |
| |
| if (max_parameter >= kParameterEnd) { |
| size_t i = 0; |
| for (int parameter = kParameterStart; parameter <= kParameterEnd; |
| ++parameter) { |
| __cpuid(cpu_info, parameter); |
| memcpy(&cpu_string[i], cpu_info, sizeof(cpu_info)); |
| i += sizeof(cpu_info); |
| } |
| cpu_string[i] = '\0'; |
| cpu_brand_ = cpu_string; |
| } |
| |
| static constexpr int kParameterContainingNonStopTimeStampCounter = 0x80000007; |
| if (max_parameter >= kParameterContainingNonStopTimeStampCounter) { |
| __cpuid(cpu_info, kParameterContainingNonStopTimeStampCounter); |
| has_non_stop_time_stamp_counter_ = (cpu_info[3] & (1 << 8)) != 0; |
| } |
| |
| if (!has_non_stop_time_stamp_counter_ && is_running_in_vm_) { |
| int cpu_info_hv[4] = {}; |
| __cpuid(cpu_info_hv, 0x40000000); |
| if (cpu_info_hv[1] == 0x7263694D && // Micr |
| cpu_info_hv[2] == 0x666F736F && // osof |
| cpu_info_hv[3] == 0x76482074) { // t Hv |
| // If CPUID says we have a variant TSC and a hypervisor has identified |
| // itself and the hypervisor says it is Microsoft Hyper-V, then treat |
| // TSC as invariant. |
| // |
| // Microsoft Hyper-V hypervisor reports variant TSC as there are some |
| // scenarios (eg. VM live migration) where the TSC is variant, but for |
| // our purposes we can treat it as invariant. |
| has_non_stop_time_stamp_counter_ = true; |
| } |
| } |
| #elif defined(ARCH_CPU_ARM_FAMILY) |
| #if (defined(OS_ANDROID) || defined(OS_LINUX)) |
| cpu_brand_ = *CpuInfoBrand(); |
| #elif defined(OS_WIN) |
| // Windows makes high-resolution thread timing information available in |
| // user-space. |
| has_non_stop_time_stamp_counter_ = true; |
| #endif |
| #endif |
| } |
| |
| CPU::IntelMicroArchitecture CPU::GetIntelMicroArchitecture() const { |
| if (has_avx2()) return AVX2; |
| if (has_avx()) return AVX; |
| if (has_sse42()) return SSE42; |
| if (has_sse41()) return SSE41; |
| if (has_ssse3()) return SSSE3; |
| if (has_sse3()) return SSE3; |
| if (has_sse2()) return SSE2; |
| if (has_sse()) return SSE; |
| return PENTIUM; |
| } |
| |
| } // namespace base |