mirror of git://sourceware.org/git/glibc.git
9620398097
Install <sys/platform/x86.h> so that programmers can do
#if __has_include(<sys/platform/x86.h>)
#include <sys/platform/x86.h>
#endif
...
if (CPU_FEATURE_USABLE (SSE2))
...
if (CPU_FEATURE_USABLE (AVX2))
...
<sys/platform/x86.h> exports only:
enum
{
COMMON_CPUID_INDEX_1 = 0,
COMMON_CPUID_INDEX_7,
COMMON_CPUID_INDEX_80000001,
COMMON_CPUID_INDEX_D_ECX_1,
COMMON_CPUID_INDEX_80000007,
COMMON_CPUID_INDEX_80000008,
COMMON_CPUID_INDEX_7_ECX_1,
/* Keep the following line at the end. */
COMMON_CPUID_INDEX_MAX
};
struct cpuid_features
{
struct cpuid_registers cpuid;
struct cpuid_registers usable;
};
struct cpu_features
{
struct cpu_features_basic basic;
struct cpuid_features features[COMMON_CPUID_INDEX_MAX];
};
/* Get a pointer to the CPU features structure. */
extern const struct cpu_features *__x86_get_cpu_features
(unsigned int max) __attribute__ ((const));
Since all feature checks are done through macros, programs compiled with
a newer <sys/platform/x86.h> are compatible with the older glibc binaries
as long as the layout of struct cpu_features is identical. The features
array can be expanded with backward binary compatibility for both .o and
.so files. When COMMON_CPUID_INDEX_MAX is increased to support new
processor features, __x86_get_cpu_features in the older glibc binaries
returns NULL and HAS_CPU_FEATURE/CPU_FEATURE_USABLE return false on the
new processor feature. No new symbol version is neeeded.
Both CPU_FEATURE_USABLE and HAS_CPU_FEATURE are provided. HAS_CPU_FEATURE
can be used to identify processor features.
Note: Although GCC has __builtin_cpu_supports, it only supports a subset
of <sys/platform/x86.h> and it is equivalent to CPU_FEATURE_USABLE. It
doesn't support HAS_CPU_FEATURE.
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|---|---|---|
| .. | ||
| 64 | ||
| x32 | ||
| Implies | ||
| Makefile | ||
| Versions | ||
| ____longjmp_chk.S | ||
| __start_context.S | ||
| brk.c | ||
| clone.S | ||
| compat-timer.h | ||
| configure | ||
| configure.ac | ||
| dl-cache.h | ||
| dl-procinfo.c | ||
| dl-procinfo.h | ||
| getcontext.S | ||
| kernel-features.h | ||
| kernel_stat.h | ||
| ldconfig.h | ||
| ldd-rewrite.sed | ||
| libmvec.abilist | ||
| makecontext.c | ||
| readelflib.c | ||
| register-dump.h | ||
| setcontext.S | ||
| sigaction.c | ||
| sigaltstack-offsets.sym | ||
| sigcontextinfo.h | ||
| swapcontext.S | ||
| syscall.S | ||
| syscalls.list | ||
| sysdep.S | ||
| sysdep.h | ||
| timer_create.c | ||
| timer_delete.c | ||
| timer_getoverr.c | ||
| timer_gettime.c | ||
| timer_settime.c | ||
| ucontext_i.sym | ||
| vfork.S | ||