x86: Set dl_platform and dl_hwcap from CPU features [BZ #21391]

dl_platform and dl_hwcap are set from AT_PLATFORM and AT_HWCAP very
early during startup.  They are used by dynamic linker to determine
platform and build an array of hardware capability names, which are
added to search path when loading shared object.  dl_platform and
dl_hwcap are unused on x86-64.  On i386, i386, i486, i586 and i686
platforms were supported and only SSE2 capability was used.

On x86, usage of AT_PLATFORM and AT_HWCAP to determine platform and
processor capabilities is obsolete since all information is available
in dl_x86_cpu_features.  This patch sets dl_platform and dl_hwcap from
dl_x86_cpu_features in dynamic linker.  On i386, the available plaforms
are changed to i586 and i686 since i386 has been deprecated.  On x86-64,
the available plaforms are haswell, which is for Haswell class processors
with BMI1, BMI2, LZCNT, MOVBE, POPCNT, AVX2 and FMA, and xeon_phi, which
is for Xeon Phi class processors with AVX512F, AVX512CD, AVX512ER and
AVX512PF.  A capability, avx512_1, is also added to x86-64 for AVX512
ISAs: AVX512F, AVX512CD, AVX512BW, AVX512DQ and AVX512VL.

	[BZ #21391]
	* sysdeps/i386/dl-machine.h (dl_platform_init) [IS_IN (rtld)]:
	Only call init_cpu_features.
	[!IS_IN (rtld)]: Only set GLRO(dl_platform) to NULL if needed.
	* sysdeps/x86_64/dl-machine.h (dl_platform_init): Likewise.
	* sysdeps/i386/dl-procinfo.h: Removed.
	* sysdeps/unix/sysv/linux/i386/dl-procinfo.h: Don't include
	<sysdeps/i386/dl-procinfo.h> nor <ldsodefs.h>.  Include
	<sysdeps/x86/dl-procinfo.h>.
	(_dl_procinfo): Replace _DL_HWCAP_COUNT with 32.
	* sysdeps/unix/sysv/linux/x86_64/dl-procinfo.h [!IS_IN (ldconfig)]:
	Include <sysdeps/x86/dl-procinfo.h> instead of
	 <sysdeps/generic/dl-procinfo.h>.
	* sysdeps/x86/cpu-features.c: Include <dl-hwcap.h>.
	(init_cpu_features): Set dl_platform, dl_hwcap and dl_hwcap_mask.
	* sysdeps/x86/cpu-features.h (bit_cpu_LZCNT): New.
	(bit_cpu_MOVBE): Likewise.
	(bit_cpu_BMI1): Likewise.
	(bit_cpu_BMI2): Likewise.
	(index_cpu_BMI1): Likewise.
	(index_cpu_BMI2): Likewise.
	(index_cpu_LZCNT): Likewise.
	(index_cpu_MOVBE): Likewise.
	(index_cpu_POPCNT): Likewise.
	(reg_BMI1): Likewise.
	(reg_BMI2): Likewise.
	(reg_LZCNT): Likewise.
	(reg_MOVBE): Likewise.
	(reg_POPCNT): Likewise.
	* sysdeps/x86/dl-hwcap.h: New file.
	* sysdeps/x86/dl-procinfo.h: Likewise.
	* sysdeps/x86/dl-procinfo.c (_dl_x86_hwcap_flags): New.
	(_dl_x86_platforms): Likewise.

1 files changed, 37 insertions, 1 deletions

diff --git a/sysdeps/x86/dl-procinfo.c b/sysdeps/x86/dl-procinfo.c
index 9d154bfc62..43ab8fe25b 100644
--- a/sysdeps/x86/dl-procinfo.c
+++ b/sysdeps/x86/dl-procinfo.c
@@ -16,7 +16,11 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-/* If anything should be added here check whether the size of each string
+/* This information must be kept in sync with the _DL_HWCAP_COUNT,
+   HWCAP_PLATFORMS_START and HWCAP_PLATFORMS_COUNT definitions in
+   dl-hwcap.h.
+
+   If anything should be added here check whether the size of each string
    is still ok with the given array size.
 
    All the #ifdefs in the definitions are quite irritating but
@@ -50,3 +54,35 @@ PROCINFO_CLASS struct cpu_features _dl_x86_cpu_features
 ,
 # endif
 #endif
+
+#if !defined PROCINFO_DECL && defined SHARED
+  ._dl_x86_hwcap_flags
+#else
+PROCINFO_CLASS const char _dl_x86_hwcap_flags[2][9]
+#endif
+#ifndef PROCINFO_DECL
+= {
+    "sse2", "avx512_1"
+  }
+#endif
+#if !defined SHARED || defined PROCINFO_DECL
+;
+#else
+,
+#endif
+
+#if !defined PROCINFO_DECL && defined SHARED
+  ._dl_x86_platforms
+#else
+PROCINFO_CLASS const char _dl_x86_platforms[4][9]
+#endif
+#ifndef PROCINFO_DECL
+= {
+    "i586", "i686", "haswell", "xeon_phi"
+  }
+#endif
+#if !defined SHARED || defined PROCINFO_DECL
+;
+#else
+,
+#endif