Line data    Source code

       1             : /* SPDX-License-Identifier: GPL-2.0 */
       2             : #ifndef _ASM_X86_PVCLOCK_H
       3             : #define _ASM_X86_PVCLOCK_H
       4             : 
       5             : #include <asm/clocksource.h>
       6             : #include <asm/pvclock-abi.h>
       7             : 
       8             : /* some helper functions for xen and kvm pv clock sources */
       9             : u64 pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
      10             : u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src);
      11             : void pvclock_set_flags(u8 flags);
      12             : unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
      13             : void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
      14             :                             struct pvclock_vcpu_time_info *vcpu,
      15             :                             struct timespec64 *ts);
      16             : void pvclock_resume(void);
      17             : 
      18             : void pvclock_touch_watchdogs(void);
      19             : 
      20             : static __always_inline
      21      654685 : unsigned pvclock_read_begin(const struct pvclock_vcpu_time_info *src)
      22             : {
      23      654685 :         unsigned version = src->version & ~1;
      24             :         /* Make sure that the version is read before the data. */
      25      654685 :         virt_rmb();
      26      659354 :         return version;
      27             : }
      28             : 
      29             : static __always_inline
      30      661195 : bool pvclock_read_retry(const struct pvclock_vcpu_time_info *src,
      31             :                         unsigned version)
      32             : {
      33             :         /* Make sure that the version is re-read after the data. */
      34      661195 :         virt_rmb();
      35      662601 :         return unlikely(version != src->version);
      36             : }
      37             : 
      38             : /*
      39             :  * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
      40             :  * yielding a 64-bit result.
      41             :  */
      42      661193 : static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
      43             : {
      44      661193 :         u64 product;
      45             : #ifdef __i386__
      46             :         u32 tmp1, tmp2;
      47             : #else
      48      661193 :         ulong tmp;
      49             : #endif
      50             : 
      51      661193 :         if (shift < 0)
      52      661193 :                 delta >>= -shift;
      53             :         else
      54           0 :                 delta <<= shift;
      55             : 
      56             : #ifdef __i386__
      57             :         __asm__ (
      58             :                 "mul  %5       ; "
      59             :                 "mov  %4,%%eax ; "
      60             :                 "mov  %%edx,%4 ; "
      61             :                 "mul  %5       ; "
      62             :                 "xor  %5,%5    ; "
      63             :                 "add  %4,%%eax ; "
      64             :                 "adc  %5,%%edx ; "
      65             :                 : "=A" (product), "=r" (tmp1), "=r" (tmp2)
      66             :                 : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
      67             : #elif defined(__x86_64__)
      68      661193 :         __asm__ (
      69             :                 "mulq %[mul_frac] ; shrd $32, %[hi], %[lo]"
      70             :                 : [lo]"=a"(product),
      71             :                   [hi]"=d"(tmp)
      72             :                 : "0"(delta),
      73      661193 :                   [mul_frac]"rm"((u64)mul_frac));
      74             : #else
      75             : #error implement me!
      76             : #endif
      77             : 
      78      661193 :         return product;
      79             : }
      80             : 
      81             : static __always_inline
      82      661193 : u64 __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src, u64 tsc)
      83             : {
      84      661193 :         u64 delta = tsc - src->tsc_timestamp;
      85     1322386 :         u64 offset = pvclock_scale_delta(delta, src->tsc_to_system_mul,
      86      661193 :                                              src->tsc_shift);
      87      661193 :         return src->system_time + offset;
      88             : }
      89             : 
      90             : struct pvclock_vsyscall_time_info {
      91             :         struct pvclock_vcpu_time_info pvti;
      92             : } __attribute__((__aligned__(SMP_CACHE_BYTES)));
      93             : 
      94             : #define PVTI_SIZE sizeof(struct pvclock_vsyscall_time_info)
      95             : 
      96             : #ifdef CONFIG_PARAVIRT_CLOCK
      97             : void pvclock_set_pvti_cpu0_va(struct pvclock_vsyscall_time_info *pvti);
      98             : struct pvclock_vsyscall_time_info *pvclock_get_pvti_cpu0_va(void);
      99             : #else
     100             : static inline struct pvclock_vsyscall_time_info *pvclock_get_pvti_cpu0_va(void)
     101             : {
     102             :         return NULL;
     103             : }
     104             : #endif
     105             : 
     106             : #endif /* _ASM_X86_PVCLOCK_H */