diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-11-30 17:00:23 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-11-30 17:00:23 -0800 |
| commit | 7c17e486e865d616f0e37c7f7f0e4dcfab704cd8 (patch) | |
| tree | f238c1c0055100f9e7a134211e934c5aecf6d873 /arch/x86/kernel/head_32.S | |
| parent | 8fdd78eeb11aeda018b22424f863344ef83a92d3 (diff) | |
| parent | 644c154186386bb1fa6446bc5e037b9ed098db46 (diff) | |
Merge branch 'x86/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Peter Anvin.
This includes the resume-time FPU corruption fix from the chromeos guys,
marked for stable.
* 'x86/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, fpu: Avoid FPU lazy restore after suspend
x86-32: Unbreak booting on some 486 clones
x86, kvm: Remove incorrect redundant assembly constraint
Diffstat (limited to 'arch/x86/kernel/head_32.S')
| -rw-r--r-- | arch/x86/kernel/head_32.S | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index 957a47aec64..4dac2f68ed4 100644 --- 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 |