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.

9 files changed, 181 insertions, 31 deletions

diff --git a/ChangeLog b/ChangeLog
index 8970d74f54..0699c5719a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,33 @@
+2012-05-17  Andreas Jaeger  <aj@suse.de>
+	    Carlos O'Donell  <carlos_odonell@mentor.com>
+
+	[BZ #14059]
+	* sysdeps/x86_64/multiarch/init-arch.h
+	(bit_YMM_Usable): Rename to...
+	(bit_AVX_Usable): ... this.
+	(bit_FMA4_Usable): New macro.
+	(bit_XMM_state): New macro.
+	(bit_YMM_state): New macro.
+	[__ASSEMBLER__] (index_YMM_Usable): Rename to...
+	[__ASSEMBLER__] (index_AVX_Usable): ... this.
+	[__ASSEMBLER__] (index_FMA4_Usable): New macro.
+	(CPUID_OSXSAVE): New macro.
+	(CPUID_AVX): New macro.
+	(CPUID_FMA4): New macro.
+	(index_YMM_Usable): Rename to...
+	(index_AVX_Usable): ... this.
+	(HAS_AVX): Use HAS_ARCH_FEATURE.
+	(HAS_FMA4): Likewise.
+	(HAS_YMM_USABLE): Remove.
+	* sysdeps/x86_64/multiarch/init-arch.c (__init_cpu_features):
+	Enable AVX or FMA4 IFF YMM and XMM states are usable and the features
+	are present.
+	* sysdeps/x86_64/multiarch/strcmp.S: Use bit_AVX_Usable.
+	* sysdeps/i386/i686/multiarch/Makefile: Add test-multiarch to tests.
+	* sysdeps/x86_64/multiarch/Makefile: Likewise.
+	* sysdeps/i386/i686/multiarch/test-multiarch.c: New file.
+	* sysdeps/x86_64/multiarch/test-multiarch.c: New file.
+
 2012-05-17  Chris Metcalf  <cmetcalf@tilera.com>
 
 	* math/libm-test.c: Support platforms without multiple rounding modes.
diff --git a/NEWS b/NEWS
index 2d2b6a8f14..48ceada32f 100644
--- a/NEWS
+++ b/NEWS
@@ -27,7 +27,7 @@ Version 2.16
   13919, 13920, 13921, 13922, 13923, 13924, 13926, 13927, 13928, 13938,
   13941, 13942, 13954, 13955, 13956, 13963, 13967, 13970, 13973, 13979,
   13983, 13986, 14012, 14027, 14033, 14034, 14040, 14043, 14044, 14049,
-  14053, 14055, 14064, 14080, 14083, 14103, 14104, 14109
+  14053, 14055, 14059, 14064, 14080, 14083, 14103, 14104, 14109
 
 * ISO C11 support:
 
diff --git a/sysdeps/i386/i686/multiarch/Makefile b/sysdeps/i386/i686/multiarch/Makefile
index b764e5b825..8946bfa586 100644
--- a/sysdeps/i386/i686/multiarch/Makefile
+++ b/sysdeps/i386/i686/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/i386/i686/multiarch/test-multiarch.c b/sysdeps/i386/i686/multiarch/test-multiarch.c
new file mode 100644
index 0000000000..593cfec273
--- /dev/null
+++ b/sysdeps/i386/i686/multiarch/test-multiarch.c
@@ -0,0 +1 @@
+#include <sysdeps/x86_64/multiarch/test-multiarch.c>
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"