x86: Update CPU feature detection [BZ #26149]

1. Divide architecture features into the usable features and the preferred
features.  The usable features are for correctness and can be exported in
a stable ABI.  The preferred features are for performance and only for
glibc internal use.
2. Change struct cpu_features to

struct cpu_features
{
  struct cpu_features_basic basic;
  unsigned int *usable_p;
  struct cpuid_registers cpuid[COMMON_CPUID_INDEX_MAX];
  unsigned int usable[USABLE_FEATURE_INDEX_MAX];
  unsigned int preferred[PREFERRED_FEATURE_INDEX_MAX];
  ...
};

and initialize usable_p to pointer to the usable arary so that

struct cpu_features
{
  struct cpu_features_basic basic;
  unsigned int *usable_p;
  struct cpuid_registers cpuid[COMMON_CPUID_INDEX_MAX];
};

can be exported via a stable ABI.  The cpuid and usable arrays can be
expanded with backward binary compatibility for both .o and .so files.
3. Add COMMON_CPUID_INDEX_7_ECX_1 for AVX512_BF16.
4. Detect ENQCMD, PKS, AVX512_VP2INTERSECT, MD_CLEAR, SERIALIZE, HYBRID,
TSXLDTRK, L1D_FLUSH, CORE_CAPABILITIES and AVX512_BF16.
5. Rename CAPABILITIES to ARCH_CAPABILITIES.
6. Check if AVX512_VP2INTERSECT, AVX512_BF16 and PKU are usable.
7. Update CPU feature detection test.

1 files changed, 1 insertions, 1 deletions

diff --git a/sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h b/sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h
index eeb2a4854d..8205ad11e6 100644
--- a/sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h
+++ b/sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h
@@ -33,7 +33,7 @@
   case 21:								  \
     if (!__libc_enable_secure						  \
 	&& memcmp (envline, "PREFER_MAP_32BIT_EXEC", 21) == 0)		  \
-      GLRO(dl_x86_cpu_features).feature[index_arch_Prefer_MAP_32BIT_EXEC] \
+      GLRO(dl_x86_cpu_features).preferred[index_arch_Prefer_MAP_32BIT_EXEC] \
 	|= bit_arch_Prefer_MAP_32BIT_EXEC;				  \
     break;