Merge branch 'for_3.8-rc1' into v4l_for_linus

[deliverable/linux.git] / arch / x86 / kernel / head_32.S

diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index 957a47aec64e12d1833af368c337e4b4e03f56bd..4dac2f68ed4aaf2bf35e10687dbdf44234829347 100644 (file)
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -292,8 +292,8 @@ default_entry:
  *     be using the global pages. 
  *
  *     NOTE! If we are on a 486 we may have no cr4 at all!
- *     Specifically, cr4 exists if and only if CPUID exists,
- *     which in turn exists if and only if EFLAGS.ID exists.
+ *     Specifically, cr4 exists if and only if CPUID exists
+ *     and has flags other than the FPU flag set.
  */
        movl $X86_EFLAGS_ID,%ecx
        pushl %ecx
@@ -308,6 +308,11 @@ default_entry:
        testl %ecx,%eax
        jz 6f                   # No ID flag = no CPUID = no CR4
 
+       movl $1,%eax
+       cpuid
+       andl $~1,%edx           # Ignore CPUID.FPU
+       jz 6f                   # No flags or only CPUID.FPU = no CR4
+
        movl pa(mmu_cr4_features),%eax
        movl %eax,%cr4