Fix concurrent handling of __cpu_features.

(cherry picked from commit 22f4f44b6727887957aa1d4039eba290b064da63)

3 files changed, 35 insertions, 14 deletions

diff --git a/ChangeLog b/ChangeLog
index 5c3a1cd65c..75bd6b87b7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+2010-04-04  H.J. Lu  <hongjiu.lu@intel.com>
+	    Ulrich Drepper  <drepper@redhat.com>
+
+	[BZ #11292]
+	* sysdeps/x86_64/multiarch/init-arch.c (__init_cpu_features): Allow
+	concurrent initialization and use of __cpu_features.
+
+2010-04-04  Ulrich Drepper  <drepper@redhat.com>
+
+	* sysdeps/x86_64/multiarch/init-arch.h (cpu_features): Add tag to
+	the enum.
+
 2010-04-03  Ulrich Drepper  <drepper@redhat.com>
 
 	[BZ #11333]
diff --git a/sysdeps/x86_64/multiarch/init-arch.c b/sysdeps/x86_64/multiarch/init-arch.c
index 7823aceb9b..0fe2f86b4f 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 Free Software Foundation, Inc.
+   Copyright (C) 2008, 2009, 2010 Free Software Foundation, Inc.
    Contributed by Ulrich Drepper <drepper@redhat.com>.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -18,6 +18,7 @@
    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
    02111-1307 USA.  */
 
+#include <atomic.h>
 #include <cpuid.h>
 #include "init-arch.h"
 
@@ -26,7 +27,7 @@ struct cpu_features __cpu_features attribute_hidden;
 
 
 static void
-get_common_indeces (void)
+get_common_indeces (unsigned int *family, unsigned int *model)
 {
   __cpuid (1, __cpu_features.cpuid[COMMON_CPUID_INDEX_1].eax,
 	   __cpu_features.cpuid[COMMON_CPUID_INDEX_1].ebx,
@@ -34,8 +35,8 @@ get_common_indeces (void)
 	   __cpu_features.cpuid[COMMON_CPUID_INDEX_1].edx);
 
   unsigned int eax = __cpu_features.cpuid[COMMON_CPUID_INDEX_1].eax;
-  __cpu_features.family = (eax >> 8) & 0x0f;
-  __cpu_features.model = (eax >> 4) & 0x0f;
+  *family = (eax >> 8) & 0x0f;
+  *model = (eax >> 4) & 0x0f;
 }
 
 
@@ -45,36 +46,44 @@ __init_cpu_features (void)
   unsigned int ebx;
   unsigned int ecx;
   unsigned int edx;
+  unsigned int family = 0;
+  unsigned int model = 0;
+  enum cpu_features_kind kind;
 
   __cpuid (0, __cpu_features.max_cpuid, ebx, ecx, edx);
 
   /* This spells out "GenuineIntel".  */
   if (ebx == 0x756e6547 && ecx == 0x6c65746e && edx == 0x49656e69)
     {
-      __cpu_features.kind = arch_kind_intel;
+      kind = arch_kind_intel;
 
-      get_common_indeces ();
+      get_common_indeces (&family, &model);
 
       unsigned int eax = __cpu_features.cpuid[COMMON_CPUID_INDEX_1].eax;
       unsigned int extended_family = (eax >> 20) & 0xff;
       unsigned int extended_model = (eax >> 12) & 0xf0;
       if (__cpu_features.family == 0x0f)
 	{
-	  __cpu_features.family += extended_family;
-	  __cpu_features.model += extended_model;
+	  family += extended_family;
+	  model += extended_model;
 	}
       else if (__cpu_features.family == 0x06)
-	__cpu_features.model += extended_model;
+	model += extended_model;
     }
   /* This spells out "AuthenticAMD".  */
   else if (ebx == 0x68747541 && ecx == 0x444d4163 && edx == 0x69746e65)
     {
-      __cpu_features.kind = arch_kind_amd;
+      kind = arch_kind_amd;
 
-      get_common_indeces ();
+      get_common_indeces (&family, &model);
     }
   else
-    __cpu_features.kind = arch_kind_other;
+    kind = arch_kind_other;
+
+  __cpu_features.family = family;
+  __cpu_features.model = model;
+  atomic_write_barrier ();
+  __cpu_features.kind = kind;
 }
 
 #undef __get_cpu_features
diff --git a/sysdeps/x86_64/multiarch/init-arch.h b/sysdeps/x86_64/multiarch/init-arch.h
index 9b12831a6e..f6320693bf 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 Free Software Foundation, Inc.
+   Copyright (C) 2008, 2009, 2010 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
@@ -27,7 +27,7 @@ enum
 
 extern struct cpu_features
 {
-  enum
+  enum cpu_features_kind
     {
       arch_kind_unknown = 0,
       arch_kind_intel,