--- arch/x86/include/asm/pvclock.h

+++ arch/x86/include/asm/pvclock.h

@@ -12,4 +12,42 @@ void pvclock_read_wallclock(struct pvclo

struct timespec *ts);

void pvclock_resume(void);

+/*

+ * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,

+ * yielding a 64-bit result.

+ */

+static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)

+{

+ u64 product;

+#ifdef __i386__

+ u32 tmp1, tmp2;

+#endif

+

+ if (shift < 0)

+ delta >>= -shift;

+ else

+ delta <<= shift;

+

+#ifdef __i386__

+ __asm__ (

+ "mul %5 ; "

+ "mov %4,%%eax ; "

+ "mov %%edx,%4 ; "

+ "mul %5 ; "

+ "xor %5,%5 ; "

+ "add %4,%%eax ; "

+ "adc %5,%%edx ; "

+ : "=A" (product), "=r" (tmp1), "=r" (tmp2)

+ : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );

+#elif defined(__x86_64__)

+ __asm__ (

+ "mul %%rdx ; shrd $32,%%rdx,%%rax"

+ : "=a" (product) : "0" (delta), "d" ((u64)mul_frac) );

+#else

+#error implement me!

+#endif

+

+ return product;

+}

+

#endif /* _ASM_X86_PVCLOCK_H */