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| author | Borislav Petkov <bp@suse.de> | 2016-04-08 00:31:49 (GMT) |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-04-13 08:20:42 (GMT) |
| commit | 96e5d28ae7a5250f3deb2434f1895c9daf48b1bd (patch) | |
| tree | 5bd439d3de521744c90937879ba0ee3f032e1142 /arch/x86/entry | |
| parent | 0230bb038fa99af0c425fc4cffed307e545a9642 (diff) | |
| download | linux-96e5d28ae7a5250f3deb2434f1895c9daf48b1bd.tar.xz | |
x86/cpu: Add Erratum 88 detection on AMD
Erratum 88 affects old AMD K8s, where a SWAPGS fails to cause an input
dependency on GS. Therefore, we need to MFENCE before it.
But that MFENCE is expensive and unnecessary on the remaining x86 CPUs
out there so patch it out on the CPUs which don't require it.
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Andy Lutomirski <luto@kernel.org
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rudolf Marek <r.marek@assembler.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/aec6b2df1bfc56101d4e9e2e5d5d570bf41663c6.1460075211.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/entry')
| -rw-r--r-- | arch/x86/entry/entry_64.S | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 858b555..64d2033 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -783,7 +783,7 @@ ENTRY(native_load_gs_index) SWAPGS gs_change: movl %edi, %gs -2: mfence /* workaround */ +2: ALTERNATIVE "", "mfence", X86_BUG_SWAPGS_FENCE SWAPGS popfq ret |