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
  15 /*
  16  * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
  17  * yielding a 64-bit result.
  18  */
  19 static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
  20 {
  21         u64 product;
  22 #ifdef __i386__
  23         u32 tmp1, tmp2;
  24 #endif
  25
  26         if (shift < 0)
  27                 delta >>= -shift;
  28         else
  29                 delta <<= shift;
  30
  31 #ifdef __i386__
  32         __asm__ (
  33                 "mul  %5       ; "
  34                 "mov  %4,%%eax ; "
  35                 "mov  %%edx,%4 ; "
  36                 "mul  %5       ; "
  37                 "xor  %5,%5    ; "
  38                 "add  %4,%%eax ; "
  39                 "adc  %5,%%edx ; "
  40                 : "=A" (product), "=r" (tmp1), "=r" (tmp2)
  41                 : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
  42 #elif defined(__x86_64__)
  43         __asm__ (
  44                 "mul %%rdx ; shrd $32,%%rdx,%%rax"
  45                 : "=a" (product) : "0" (delta), "d" ((u64)mul_frac) );
  46 #else
  47 #error implement me!
  48 #endif
  49
  50         return product;
  51 }
  52
  53 #endif /* _ASM_X86_PVCLOCK_H */