x86/mce: Improve memcpy_mcsafe()

Use the mcsafe_key defined in the previous patch to make decisions on which
copy function to use. We can't use the FEATURE bit any more because PCI
quirks run too late to affect the patching of code. So we use a static key.

Turn memcpy_mcsafe() into an inline function to make life easier for
callers. The assembly code that actually does the copy is now named
memcpy_mcsafe_unrolled()

Signed-off-by: Tony Luck <tony.luck@intel.com>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Boris Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/bfde2fc774e94f53d91b70a4321c85a0d33e7118.1472754712.git.tony.luck@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 3 insertions, 3 deletions

diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S
index 2ec0b0abbfaa..49e6ebac7e73 100644
--- a/arch/x86/lib/memcpy_64.S
+++ b/arch/x86/lib/memcpy_64.S
@@ -181,11 +181,11 @@ ENDPROC(memcpy_orig)
 
 #ifndef CONFIG_UML
 /*
- * memcpy_mcsafe - memory copy with machine check exception handling
+ * memcpy_mcsafe_unrolled - memory copy with machine check exception handling
  * Note that we only catch machine checks when reading the source addresses.
  * Writes to target are posted and don't generate machine checks.
  */
-ENTRY(memcpy_mcsafe)
+ENTRY(memcpy_mcsafe_unrolled)
         cmpl $8, %edx
         /* Less than 8 bytes? Go to byte copy loop */
         jb .L_no_whole_words
@@ -273,7 +273,7 @@ ENTRY(memcpy_mcsafe)
 .L_done_memcpy_trap:
         xorq %rax, %rax
         ret
-ENDPROC(memcpy_mcsafe)
+ENDPROC(memcpy_mcsafe_unrolled)
 
         .section .fixup, "ax"
         /* Return -EFAULT for any failure */