[PATCH] x86: more asm cleanups

Some more assembler cleanups I noticed along the way.

Signed-off-by: Zachary Amsden <zach@vmware.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/include/asm-i386/msr.h b/include/asm-i386/msr.h
index c76fce8badbb..62b76cd96957 100644
--- a/include/asm-i386/msr.h
+++ b/include/asm-i386/msr.h
@@ -47,6 +47,21 @@ static inline void wrmsrl (unsigned long msr, unsigned long long val)
                      : "c" (msr), "0" (a), "d" (b), "i" (-EFAULT));\
         ret__; })
 
+/* rdmsr with exception handling */
+#define rdmsr_safe(msr,a,b) ({ int ret__;                                               \
+        asm volatile("2: rdmsr ; xorl %0,%0\n"                                          \
+                     "1:\n\t"                                                           \
+                     ".section .fixup,\"ax\"\n\t"                                       \
+                     "3:  movl %4,%0 ; jmp 1b\n\t"                                      \
+                     ".previous\n\t"                                                    \
+                     ".section __ex_table,\"a\"\n"                                      \
+                     "   .align 4\n\t"                                                  \
+                     "   .long  2b,3b\n\t"                                              \
+                     ".previous"                                                        \
+                     : "=r" (ret__), "=a" (*(a)), "=d" (*(b))                           \
+                     : "c" (msr), "i" (-EFAULT));\
+        ret__; })
+
 #define rdtsc(low,high) \
      __asm__ __volatile__("rdtsc" : "=a" (low), "=d" (high))