#include "base/cpu.h"
+#include <stdlib.h>
#include <string.h>
#include <algorithm>
+#include "base/basictypes.h"
+#include "base/strings/string_piece.h"
#include "build/build_config.h"
+#if defined(ARCH_CPU_ARM_FAMILY) && (defined(OS_ANDROID) || defined(OS_LINUX))
+#include "base/files/file_util.h"
+#include "base/lazy_instance.h"
+#endif
+
#if defined(ARCH_CPU_X86_FAMILY)
#if defined(_MSC_VER)
#include <intrin.h>
+#include <immintrin.h> // For _xgetbv()
#endif
#endif
has_ssse3_(false),
has_sse41_(false),
has_sse42_(false),
+ has_avx_(false),
+ has_avx_hardware_(false),
+ has_aesni_(false),
has_non_stop_time_stamp_counter_(false),
+ has_broken_neon_(false),
cpu_vendor_("unknown") {
Initialize();
}
+namespace {
+
#if defined(ARCH_CPU_X86_FAMILY)
#ifndef _MSC_VER
);
}
-void __cpuidex(int cpu_info[4], int info_type, int info_index) {
- __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"(info_index)
- );
-}
-
#else
void __cpuid(int cpu_info[4], int info_type) {
);
}
-void __cpuidex(int cpu_info[4], int info_type, int info_index) {
- __asm__ volatile (
- "cpuid \n\t"
- : "=a"(cpu_info[0]), "=b"(cpu_info[1]), "=c"(cpu_info[2]), "=d"(cpu_info[3])
- : "a"(info_type), "c"(info_index)
- );
+#endif
+
+// _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 _xgetbv(uint32 xcr) {
+ uint32 eax, edx;
+
+ __asm__ volatile ("xgetbv" : "=a" (eax), "=d" (edx) : "c" (xcr));
+ return (static_cast<uint64>(edx) << 32) | eax;
}
-#endif
-#endif // _MSC_VER
+#endif // !_MSC_VER
#endif // ARCH_CPU_X86_FAMILY
+#if defined(ARCH_CPU_ARM_FAMILY) && (defined(OS_ANDROID) || defined(OS_LINUX))
+class LazyCpuInfoValue {
+ public:
+ LazyCpuInfoValue() : has_broken_neon_(false) {
+ // 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: ";
+
+ // This function also calculates whether we believe that this CPU has a
+ // broken NEON unit based on these fields from cpuinfo:
+ unsigned implementer = 0, architecture = 0, variant = 0, part = 0,
+ revision = 0;
+ const struct {
+ const char key[17];
+ unsigned *result;
+ } kUnsignedValues[] = {
+ {"CPU implementer", &implementer},
+ {"CPU architecture", &architecture},
+ {"CPU variant", &variant},
+ {"CPU part", &part},
+ {"CPU revision", &revision},
+ };
+
+ std::string contents;
+ ReadFileToString(FilePath("/proc/cpuinfo"), &contents);
+ DCHECK(!contents.empty());
+ if (contents.empty()) {
+ return;
+ }
+
+ std::istringstream iss(contents);
+ std::string line;
+ while (std::getline(iss, line)) {
+ if (brand_.empty() &&
+ (line.compare(0, strlen(kModelNamePrefix), kModelNamePrefix) == 0 ||
+ line.compare(0, strlen(kProcessorPrefix), kProcessorPrefix) == 0)) {
+ brand_.assign(line.substr(strlen(kModelNamePrefix)));
+ }
+
+ for (size_t i = 0; i < arraysize(kUnsignedValues); i++) {
+ const char *key = kUnsignedValues[i].key;
+ const size_t len = strlen(key);
+
+ if (line.compare(0, len, key) == 0 &&
+ line.size() >= len + 1 &&
+ (line[len] == '\t' || line[len] == ' ' || line[len] == ':')) {
+ size_t colon_pos = line.find(':', len);
+ if (colon_pos == std::string::npos) {
+ continue;
+ }
+
+ const StringPiece line_sp(line);
+ StringPiece value_sp = line_sp.substr(colon_pos + 1);
+ while (!value_sp.empty() &&
+ (value_sp[0] == ' ' || value_sp[0] == '\t')) {
+ value_sp = value_sp.substr(1);
+ }
+
+ // The string may have leading "0x" or not, so we use strtoul to
+ // handle that.
+ char *endptr;
+ std::string value(value_sp.as_string());
+ unsigned long int result = strtoul(value.c_str(), &endptr, 0);
+ if (*endptr == 0 && result <= UINT_MAX) {
+ *kUnsignedValues[i].result = result;
+ }
+ }
+ }
+ }
+
+ has_broken_neon_ =
+ implementer == 0x51 &&
+ architecture == 7 &&
+ variant == 1 &&
+ part == 0x4d &&
+ revision == 0;
+ }
+
+ const std::string& brand() const { return brand_; }
+ bool has_broken_neon() const { return has_broken_neon_; }
+
+ private:
+ std::string brand_;
+ bool has_broken_neon_;
+ DISALLOW_COPY_AND_ASSIGN(LazyCpuInfoValue);
+};
+
+base::LazyInstance<LazyCpuInfoValue>::Leaky g_lazy_cpuinfo =
+ LAZY_INSTANCE_INITIALIZER;
+
+#endif // defined(ARCH_CPU_ARM_FAMILY) && (defined(OS_ANDROID) ||
+ // defined(OS_LINUX))
+
+} // anonymous namespace
+
void CPU::Initialize() {
#if defined(ARCH_CPU_X86_FAMILY)
int cpu_info[4] = {-1};
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_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_avx_ = (cpu_info[2] & 0x10000000) != 0;
+ has_avx_hardware_ =
+ (cpu_info[2] & 0x10000000) != 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_ =
+ has_avx_hardware_ &&
+ (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;
}
// Get the brand string of the cpu.
__cpuid(cpu_info, parameter_containing_non_stop_time_stamp_counter);
has_non_stop_time_stamp_counter_ = (cpu_info[3] & (1 << 8)) != 0;
}
-#elif defined(ARCH_CPU_ARM_FAMILY)
- // TODO(piman): Expand this. ARM has a CPUID register, but it's not available
- // in user mode. /proc/cpuinfo has some information, but it's non standard,
- // platform-specific, and not accessible from the sandbox.
- // For some purposes, this first approximation is enough.
- // crbug.com/313454
- cpu_brand_.assign("ARM");
+#elif defined(ARCH_CPU_ARM_FAMILY) && (defined(OS_ANDROID) || defined(OS_LINUX))
+ cpu_brand_.assign(g_lazy_cpuinfo.Get().brand());
+ has_broken_neon_ = g_lazy_cpuinfo.Get().has_broken_neon();
#endif
}
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