about summary refs log tree commit diff
path: root/sysdeps/i386
diff options
context:
space:
mode:
authorH.J. Lu <hjl.tools@gmail.com>2020-06-29 18:30:54 -0700
committerH.J. Lu <hjl.tools@gmail.com>2020-09-11 17:20:52 -0700
commit9620398097de3981c1adf5233e2b3478d36bc1b3 (patch)
tree20e492ba12ab22a57ed91df3698fdf57eba54810 /sysdeps/i386
parenta92f4e6299fe0e3cb6f77e79de00817aece501ce (diff)
downloadglibc-9620398097de3981c1adf5233e2b3478d36bc1b3.tar.gz
glibc-9620398097de3981c1adf5233e2b3478d36bc1b3.tar.xz
glibc-9620398097de3981c1adf5233e2b3478d36bc1b3.zip
x86: Install <sys/platform/x86.h> [BZ #26124]
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.
Diffstat (limited to 'sysdeps/i386')
-rw-r--r--sysdeps/i386/i686/multiarch/Makefile4
-rw-r--r--sysdeps/i386/i686/multiarch/test-multiarch.c1
2 files changed, 0 insertions, 5 deletions
diff --git a/sysdeps/i386/i686/multiarch/Makefile b/sysdeps/i386/i686/multiarch/Makefile
index bf75a9947f..c4897922d7 100644
--- a/sysdeps/i386/i686/multiarch/Makefile
+++ b/sysdeps/i386/i686/multiarch/Makefile
@@ -1,7 +1,3 @@
-ifeq ($(subdir),csu)
-tests += test-multiarch
-endif
-
 ifeq ($(subdir),string)
 gen-as-const-headers += locale-defines.sym
 sysdep_routines += bzero-sse2 memset-sse2 memcpy-ssse3 mempcpy-ssse3 \
diff --git a/sysdeps/i386/i686/multiarch/test-multiarch.c b/sysdeps/i386/i686/multiarch/test-multiarch.c
deleted file mode 100644
index 593cfec273..0000000000
--- a/sysdeps/i386/i686/multiarch/test-multiarch.c
+++ /dev/null
@@ -1 +0,0 @@
-#include <sysdeps/x86_64/multiarch/test-multiarch.c>