BZ#14059: Fix AVX and FMA4 detection.

Fix AVX and FMA4 detection by following the guidelines
set out by Intel and AMD for detecting these features.

5 files changed, 148 insertions, 30 deletions

diff --git a/sysdeps/x86_64/multiarch/Makefile b/sysdeps/x86_64/multiarch/Makefile
index 9a183f068e..dd6c27d0b4 100644
--- a/sysdeps/x86_64/multiarch/Makefile
+++ b/sysdeps/x86_64/multiarch/Makefile
@@ -1,5 +1,6 @@
 ifeq ($(subdir),csu)
 aux += init-arch
+tests += test-multiarch
 gen-as-const-headers += ifunc-defines.sym
 endif
 
diff --git a/sysdeps/x86_64/multiarch/init-arch.c b/sysdeps/x86_64/multiarch/init-arch.c
index 80527ec59d..fb44dcfcf6 100644
--- a/sysdeps/x86_64/multiarch/init-arch.c
+++ b/sysdeps/x86_64/multiarch/init-arch.c
@@ -1,6 +1,6 @@
 /* Initialize CPU feature data.
    This file is part of the GNU C Library.
-   Copyright (C) 2008, 2009, 2010, 2011, 2012 Free Software Foundation, Inc.
+   Copyright (C) 2008-2012 Free Software Foundation, Inc.
    Contributed by Ulrich Drepper <drepper@redhat.com>.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -143,16 +143,23 @@ __init_cpu_features (void)
   else
     kind = arch_kind_other;
 
-  if (__cpu_features.cpuid[COMMON_CPUID_INDEX_1].ecx & bit_AVX)
+  /* Can we call xgetbv?  */
+  if (CPUID_OSXSAVE)
     {
-      /* Reset the AVX bit in case OSXSAVE is disabled.  */
-      if ((__cpu_features.cpuid[COMMON_CPUID_INDEX_1].ecx & bit_OSXSAVE) != 0
-	  && ({ unsigned int xcrlow;
-		unsigned int xcrhigh;
-		asm ("xgetbv"
-		     : "=a" (xcrlow), "=d" (xcrhigh) : "c" (0));
-		(xcrlow & 6) == 6; }))
-	__cpu_features.feature[index_YMM_Usable] |= bit_YMM_Usable;
+      unsigned int xcrlow;
+      unsigned int xcrhigh;
+      asm ("xgetbv" : "=a" (xcrlow), "=d" (xcrhigh) : "c" (0));
+      /* Is YMM and XMM state usable?  */
+      if ((xcrlow & (bit_YMM_state | bit_XMM_state)) ==
+	  (bit_YMM_state | bit_XMM_state))
+	{
+	  /* Determine if AVX is usable.  */
+	  if (CPUID_AVX)
+	    __cpu_features.feature[index_AVX_Usable] |= bit_AVX_Usable;
+	  /* Determine if FMA4 is usable.  */
+	  if (CPUID_FMA4)
+	    __cpu_features.feature[index_FMA4_Usable] |= bit_FMA4_Usable;
+	}
     }
 
   __cpu_features.family = family;
diff --git a/sysdeps/x86_64/multiarch/init-arch.h b/sysdeps/x86_64/multiarch/init-arch.h
index 5054e46f61..45e2651678 100644
--- a/sysdeps/x86_64/multiarch/init-arch.h
+++ b/sysdeps/x86_64/multiarch/init-arch.h
@@ -1,5 +1,5 @@
 /* This file is part of the GNU C Library.
-   Copyright (C) 2008, 2009, 2010, 2011, 2012 Free Software Foundation, Inc.
+   Copyright (C) 2008-2012 Free Software Foundation, Inc.
 
    The GNU C Library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
@@ -21,8 +21,10 @@
 #define bit_Prefer_SSE_for_memop	(1 << 3)
 #define bit_Fast_Unaligned_Load		(1 << 4)
 #define bit_Prefer_PMINUB_for_stringop	(1 << 5)
-#define bit_YMM_Usable			(1 << 6)
+#define bit_AVX_Usable			(1 << 6)
+#define bit_FMA4_Usable			(1 << 7)
 
+/* CPUID Feature flags.  */
 #define bit_SSE2	(1 << 26)
 #define bit_SSSE3	(1 << 9)
 #define bit_SSE4_1	(1 << 19)
@@ -33,6 +35,10 @@
 #define bit_FMA		(1 << 12)
 #define bit_FMA4	(1 << 16)
 
+/* XCR0 Feature flags.  */
+#define bit_XMM_state  (1 << 1)
+#define bit_YMM_state  (2 << 1)
+
 #ifdef	__ASSEMBLER__
 
 # include <ifunc-defines.h>
@@ -49,7 +55,8 @@
 # define index_Prefer_SSE_for_memop	FEATURE_INDEX_1*FEATURE_SIZE
 # define index_Fast_Unaligned_Load	FEATURE_INDEX_1*FEATURE_SIZE
 # define index_Prefer_PMINUB_for_stringop FEATURE_INDEX_1*FEATURE_SIZE
-# define index_YMM_Usable		FEATURE_INDEX_1*FEATURE_SIZE
+# define index_AVX_Usable		FEATURE_INDEX_1*FEATURE_SIZE
+# define index_FMA4_Usable		FEATURE_INDEX_1*FEATURE_SIZE
 
 #else	/* __ASSEMBLER__ */
 
@@ -113,35 +120,45 @@ extern const struct cpu_features *__get_cpu_features (void)
 
 /* Following are the feature tests used throughout libc.  */
 
+/* CPUID_* evaluates to true if the feature flag is enabled.
+   We always use &__cpu_features because the HAS_CPUID_* macros
+   are called only within __init_cpu_features, where we can't
+   call __get_cpu_features without infinite recursion.  */
+# define HAS_CPUID_FLAG(idx, reg, bit) \
+  (((&__cpu_features)->cpuid[idx].reg & (bit)) != 0)
+
+# define CPUID_OSXSAVE \
+  HAS_CPUID_FLAG (COMMON_CPUID_INDEX_1, ecx, bit_OSXSAVE)
+# define CPUID_AVX \
+  HAS_CPUID_FLAG (COMMON_CPUID_INDEX_1, ecx, bit_AVX)
+# define CPUID_FMA4 \
+  HAS_CPUID_FLAG (COMMON_CPUID_INDEX_80000001, ecx, bit_FMA4)
+
+/* HAS_* evaluates to true if we may use the feature at runtime.  */
 # define HAS_SSE2	HAS_CPU_FEATURE (COMMON_CPUID_INDEX_1, edx, bit_SSE2)
 # define HAS_POPCOUNT	HAS_CPU_FEATURE (COMMON_CPUID_INDEX_1, ecx, bit_POPCOUNT)
 # define HAS_SSSE3	HAS_CPU_FEATURE (COMMON_CPUID_INDEX_1, ecx, bit_SSSE3)
 # define HAS_SSE4_1	HAS_CPU_FEATURE (COMMON_CPUID_INDEX_1, ecx, bit_SSE4_1)
 # define HAS_SSE4_2	HAS_CPU_FEATURE (COMMON_CPUID_INDEX_1, ecx, bit_SSE4_2)
 # define HAS_FMA	HAS_CPU_FEATURE (COMMON_CPUID_INDEX_1, ecx, bit_FMA)
-# define HAS_AVX	HAS_CPU_FEATURE (COMMON_CPUID_INDEX_1, ecx, bit_AVX)
-# define HAS_FMA4	HAS_CPU_FEATURE (COMMON_CPUID_INDEX_80000001, ecx, bit_FMA4)
 
 # define index_Fast_Rep_String		FEATURE_INDEX_1
 # define index_Fast_Copy_Backward	FEATURE_INDEX_1
 # define index_Slow_BSF			FEATURE_INDEX_1
 # define index_Prefer_SSE_for_memop	FEATURE_INDEX_1
 # define index_Fast_Unaligned_Load	FEATURE_INDEX_1
-# define index_YMM_Usable		FEATURE_INDEX_1
+# define index_AVX_Usable		FEATURE_INDEX_1
+# define index_FMA4_Usable		FEATURE_INDEX_1
 
 # define HAS_ARCH_FEATURE(name) \
   ((__get_cpu_features ()->feature[index_##name] & (bit_##name)) != 0)
 
-# define HAS_FAST_REP_STRING	HAS_ARCH_FEATURE (Fast_Rep_String)
-
-# define HAS_FAST_COPY_BACKWARD	HAS_ARCH_FEATURE (Fast_Copy_Backward)
-
-# define HAS_SLOW_BSF		HAS_ARCH_FEATURE (Slow_BSF)
-
-# define HAS_PREFER_SSE_FOR_MEMOP HAS_ARCH_FEATURE (Prefer_SSE_for_memop)
-
-# define HAS_FAST_UNALIGNED_LOAD HAS_ARCH_FEATURE (Fast_Unaligned_Load)
-
-# define HAS_YMM_USABLE		HAS_ARCH_FEATURE (YMM_Usable)
+# define HAS_FAST_REP_STRING		HAS_ARCH_FEATURE (Fast_Rep_String)
+# define HAS_FAST_COPY_BACKWARD		HAS_ARCH_FEATURE (Fast_Copy_Backward)
+# define HAS_SLOW_BSF			HAS_ARCH_FEATURE (Slow_BSF)
+# define HAS_PREFER_SSE_FOR_MEMOP	HAS_ARCH_FEATURE (Prefer_SSE_for_memop)
+# define HAS_FAST_UNALIGNED_LOAD	HAS_ARCH_FEATURE (Fast_Unaligned_Load)
+# define HAS_AVX			HAS_ARCH_FEATURE (AVX_Usable)
+# define HAS_FMA4			HAS_ARCH_FEATURE (FMA4_Usable)
 
 #endif	/* __ASSEMBLER__ */
diff --git a/sysdeps/x86_64/multiarch/strcmp.S b/sysdeps/x86_64/multiarch/strcmp.S
index 2b9870ba93..d366d09690 100644
--- a/sysdeps/x86_64/multiarch/strcmp.S
+++ b/sysdeps/x86_64/multiarch/strcmp.S
@@ -1,5 +1,5 @@
 /* strcmp with SSE4.2
-   Copyright (C) 2009, 2010, 2011 Free Software Foundation, Inc.
+   Copyright (C) 2009-2012 Free Software Foundation, Inc.
    Contributed by Intel Corporation.
    This file is part of the GNU C Library.
 
@@ -83,6 +83,7 @@
 	.text
 ENTRY(STRCMP)
 	.type	STRCMP, @gnu_indirect_function
+	/* Manually inlined call to __get_cpu_features.  */
 	cmpl	$0, __cpu_features+KIND_OFFSET(%rip)
 	jne	1f
 	call	__init_cpu_features
@@ -100,13 +101,14 @@ END(STRCMP)
 # ifdef USE_AS_STRCASECMP_L
 ENTRY(__strcasecmp)
 	.type	__strcasecmp, @gnu_indirect_function
+	/* Manually inlined call to __get_cpu_features.  */
 	cmpl	$0, __cpu_features+KIND_OFFSET(%rip)
 	jne	1f
 	call	__init_cpu_features
 1:
 #  ifdef HAVE_AVX_SUPPORT
 	leaq	__strcasecmp_avx(%rip), %rax
-	testl	$bit_AVX, __cpu_features+CPUID_OFFSET+index_AVX(%rip)
+	testl	$bit_AVX_Usable, __cpu_features+FEATURE_OFFSET+index_AVX_Usable(%rip)
 	jnz	2f
 #  endif
 	leaq	__strcasecmp_sse42(%rip), %rax
@@ -123,13 +125,14 @@ weak_alias (__strcasecmp, strcasecmp)
 # ifdef USE_AS_STRNCASECMP_L
 ENTRY(__strncasecmp)
 	.type	__strncasecmp, @gnu_indirect_function
+	/* Manually inlined call to __get_cpu_features.  */
 	cmpl	$0, __cpu_features+KIND_OFFSET(%rip)
 	jne	1f
 	call	__init_cpu_features
 1:
 #  ifdef HAVE_AVX_SUPPORT
 	leaq	__strncasecmp_avx(%rip), %rax
-	testl	$bit_AVX, __cpu_features+CPUID_OFFSET+index_AVX(%rip)
+	testl	$bit_AVX_Usable, __cpu_features+FEATURE_OFFSET+index_AVX_Usable(%rip)
 	jnz	2f
 #  endif
 	leaq	__strncasecmp_sse42(%rip), %rax
diff --git a/sysdeps/x86_64/multiarch/test-multiarch.c b/sysdeps/x86_64/multiarch/test-multiarch.c
new file mode 100644
index 0000000000..76b1af2f8c
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/test-multiarch.c
@@ -0,0 +1,90 @@
+/* Test CPU feature data.
+   This file is part of the GNU C Library.
+   Copyright (C) 2012 Free Software Foundation, Inc.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <init-arch.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static char *cpu_flags;
+
+/* Search for flags in /proc/cpuinfo and store line
+   in cpu_flags.  */
+void
+get_cpuinfo (void)
+{
+  FILE *f;
+  char *line = NULL;
+  size_t len = 0;
+  ssize_t read;
+
+  f = fopen ("/proc/cpuinfo", "r");
+  if (f == NULL)
+    {
+      printf ("cannot open /proc/cpuinfo");
+      exit (1);
+    }
+
+  while ((read = getline (&line, &len, f)) != -1)
+    {
+      if (strncmp (line, "flags", 5) == 0)
+       {
+         cpu_flags = strdup (line);
+         break;
+       }
+    }
+  fclose (f);
+  free (line);
+}
+
+int
+check_proc (const char *proc_name, int flag, const char *name)
+{
+  int found = 0;
+
+  printf ("Checking %s:\n", name);
+  printf ("  init-arch %d\n", flag);
+  if (strstr (cpu_flags, proc_name) != NULL)
+    found = 1;
+  printf ("  cpuinfo (%s) %d\n", proc_name, found);
+
+  if (found != flag)
+    printf (" *** failure ***\n");
+
+  return (found != flag);
+}
+
+static int
+do_test (int argc, char **argv)
+{
+  int fails;
+
+  get_cpuinfo ();
+  fails = check_proc ("avx", HAS_AVX, "HAS_AVX");
+  fails += check_proc ("fma4", HAS_FMA4, "HAS_FMA4");
+  fails += check_proc ("sse4_2", HAS_SSE4_2, "HAS_SSE4_2");
+  fails += check_proc ("sse4_1", HAS_SSE4_1, "HAS_SSE4_1");
+  fails += check_proc ("ssse3", HAS_SSSE3, "HAS_SSSE3");
+  fails += check_proc ("popcnt", HAS_POPCOUNT, "HAS_POPCOUNT");
+
+  printf ("%d differences between /proc/cpuinfo and glibc code.\n", fails);
+
+  return (fails != 0);
+}
+
+#include "../../../test-skeleton.c"