[PATCH] x86: more asm cleanups
[linux-3.10.git] / include / asm-i386 / msr.h
index c76fce8badbbb32333691d293b4c1b172b7f3e58..62b76cd96957da8ddfca0a0d1a1508b373be8ab5 100644 (file)
@@ -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))