arch/x86/include/asm/pvclock.h

   1 #ifndef _ASM_X86_PVCLOCK_H
   2 #define _ASM_X86_PVCLOCK_H
   3
   4 #include <linux/clocksource.h>
   5 #include <asm/pvclock-abi.h>
   6
   7 /* some helper functions for xen and kvm pv clock sources */
   8 cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
   9 void pvclock_set_flags(u8 flags);
  10 unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
  11 void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
  12                             struct pvclock_vcpu_time_info *vcpu,
  13                             struct timespec *ts);
  14 void pvclock_resume(void);
  15
  16 /*
  17  * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
  18  * yielding a 64-bit result.
  19  */
  20 static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
  21 {
  22         u64 product;
  23 #ifdef __i386__
  24         u32 tmp1, tmp2;
  25 #else
  26         ulong tmp;
  27 #endif
  28
  29         if (shift < 0)
  30                 delta >>= -shift;
  31         else
  32                 delta <<= shift;
  33
  34 #ifdef __i386__
  35         __asm__ (
  36                 "mul  %5       ; "
  37                 "mov  %4,%%eax ; "
  38                 "mov  %%edx,%4 ; "
  39                 "mul  %5       ; "
  40                 "xor  %5,%5    ; "
  41                 "add  %4,%%eax ; "
  42                 "adc  %5,%%edx ; "
  43                 : "=A" (product), "=r" (tmp1), "=r" (tmp2)
  44                 : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
  45 #elif defined(__x86_64__)
  46         __asm__ (
  47                 "mulq %[mul_frac] ; shrd $32, %[hi], %[lo]"
  48                 : [lo]"=a"(product),
  49                   [hi]"=d"(tmp)
  50                 : "0"(delta),
  51                   [mul_frac]"rm"((u64)mul_frac));
  52 #else
  53 #error implement me!
  54 #endif
  55
  56         return product;
  57 }
  58
  59 #endif /* _ASM_X86_PVCLOCK_H */