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 #ifdef CONFIG_KVM_GUEST
   8 extern struct pvclock_vsyscall_time_info *pvclock_pvti_cpu0_va(void);
   9 #else
  10 static inline struct pvclock_vsyscall_time_info *pvclock_pvti_cpu0_va(void)
  11 {
  12         return NULL;
  13 }
  14 #endif
  15
  16 /* some helper functions for xen and kvm pv clock sources */
  17 cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
  18 u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src);
  19 void pvclock_set_flags(u8 flags);
  20 unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
  21 void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
  22                             struct pvclock_vcpu_time_info *vcpu,
  23                             struct timespec *ts);
  24 void pvclock_resume(void);
  25
  26 void pvclock_touch_watchdogs(void);
  27
  28 /*
  29  * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
  30  * yielding a 64-bit result.
  31  */
  32 static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
  33 {
  34         u64 product;
  35 #ifdef __i386__
  36         u32 tmp1, tmp2;
  37 #else
  38         ulong tmp;
  39 #endif
  40
  41         if (shift < 0)
  42                 delta >>= -shift;
  43         else
  44                 delta <<= shift;
  45
  46 #ifdef __i386__
  47         __asm__ (
  48                 "mul  %5       ; "
  49                 "mov  %4,%%eax ; "
  50                 "mov  %%edx,%4 ; "
  51                 "mul  %5       ; "
  52                 "xor  %5,%5    ; "
  53                 "add  %4,%%eax ; "
  54                 "adc  %5,%%edx ; "
  55                 : "=A" (product), "=r" (tmp1), "=r" (tmp2)
  56                 : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
  57 #elif defined(__x86_64__)
  58         __asm__ (
  59                 "mulq %[mul_frac] ; shrd $32, %[hi], %[lo]"
  60                 : [lo]"=a"(product),
  61                   [hi]"=d"(tmp)
  62                 : "0"(delta),
  63                   [mul_frac]"rm"((u64)mul_frac));
  64 #else
  65 #error implement me!
  66 #endif
  67
  68         return product;
  69 }
  70
  71 static __always_inline
  72 u64 pvclock_get_nsec_offset(const struct pvclock_vcpu_time_info *src)
  73 {
  74         u64 delta = rdtsc_ordered() - src->tsc_timestamp;
  75         return pvclock_scale_delta(delta, src->tsc_to_system_mul,
  76                                    src->tsc_shift);
  77 }
  78
  79 static __always_inline
  80 unsigned __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src,
  81                                cycle_t *cycles, u8 *flags)
  82 {
  83         unsigned version;
  84         cycle_t ret, offset;
  85         u8 ret_flags;
  86
  87         version = src->version;
  88
  89         offset = pvclock_get_nsec_offset(src);
  90         ret = src->system_time + offset;
  91         ret_flags = src->flags;
  92
  93         *cycles = ret;
  94         *flags = ret_flags;
  95         return version;
  96 }
  97
  98 struct pvclock_vsyscall_time_info {
  99         struct pvclock_vcpu_time_info pvti;
 100 } __attribute__((__aligned__(SMP_CACHE_BYTES)));
 101
 102 #define PVTI_SIZE sizeof(struct pvclock_vsyscall_time_info)
 103
 104 #endif /* _ASM_X86_PVCLOCK_H */