From: Ulrich Drepper <drepper@gmail.com>
Date: Thu, 26 Jan 2012 12:45:14 +0000 (-0500)
Subject: Reset bit_AVX in __cpu_features is OS support is missing
X-Git-Tag: glibc-2.16-tps~1053
X-Git-Url: http://sources.redhat.com/git/gitweb.cgi?p=glibc.git;a=commitdiff_plain;h=afc5ed09cbce5d6fd48b3a8c5ec427b31f996880

Reset bit_AVX in __cpu_features is OS support is missing

--- sysdeps/x86_64/multiarch/init-arch.c
+++ 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 Free Software Foundation, Inc.
+   Copyright (C) 2008, 2009, 2010, 2011, 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
@@ -144,6 +144,18 @@ __init_cpu_features (void)
   else
     kind = arch_kind_other;
 
+  if (__cpu_features.cpuid[COMMON_CPUID_INDEX_1].ecx & bit_AVX)
+    {
+      /* 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.cpuid[COMMON_CPUID_INDEX_1].ecx &= ~bit_AVX;
+    }
+
   __cpu_features.family = family;
   __cpu_features.model = model;
   atomic_write_barrier ();
--- sysdeps/x86_64/multiarch/init-arch.h
+++ 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 Free Software Foundation, Inc.
+   Copyright (C) 2008, 2009, 2010, 2011, 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
@@ -27,6 +27,7 @@
 #define bit_SSSE3	(1 << 9)
 #define bit_SSE4_1	(1 << 19)
 #define bit_SSE4_2	(1 << 20)
+#define bit_OSXSAVE	(1 << 27)
 #define bit_AVX		(1 << 28)
 #define bit_POPCOUNT	(1 << 23)
 #define bit_FMA		(1 << 12)