arch/arm64/include/asm/vdso/gettimeofday.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Copyright (C) 2018 ARM Limited
   4  */
   5 #ifndef __ASM_VDSO_GETTIMEOFDAY_H
   6 #define __ASM_VDSO_GETTIMEOFDAY_H
   7
   8 #ifndef __ASSEMBLY__
   9
  10 #include <asm/barrier.h>
  11 #include <asm/unistd.h>
  12
  13 #define VDSO_HAS_CLOCK_GETRES           1
  14
  15 static __always_inline
  16 int gettimeofday_fallback(struct __kernel_old_timeval *_tv,
  17                           struct timezone *_tz)
  18 {
  19         register struct timezone *tz asm("x1") = _tz;
  20         register struct __kernel_old_timeval *tv asm("x0") = _tv;
  21         register long ret asm ("x0");
  22         register long nr asm("x8") = __NR_gettimeofday;
  23
  24         asm volatile(
  25         "       svc #0\n"
  26         : "=r" (ret)
  27         : "r" (tv), "r" (tz), "r" (nr)
  28         : "memory");
  29
  30         return ret;
  31 }
  32
  33 static __always_inline
  34 long clock_gettime_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
  35 {
  36         register struct __kernel_timespec *ts asm("x1") = _ts;
  37         register clockid_t clkid asm("x0") = _clkid;
  38         register long ret asm ("x0");
  39         register long nr asm("x8") = __NR_clock_gettime;
  40
  41         asm volatile(
  42         "       svc #0\n"
  43         : "=r" (ret)
  44         : "r" (clkid), "r" (ts), "r" (nr)
  45         : "memory");
  46
  47         return ret;
  48 }
  49
  50 static __always_inline
  51 int clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
  52 {
  53         register struct __kernel_timespec *ts asm("x1") = _ts;
  54         register clockid_t clkid asm("x0") = _clkid;
  55         register long ret asm ("x0");
  56         register long nr asm("x8") = __NR_clock_getres;
  57
  58         asm volatile(
  59         "       svc #0\n"
  60         : "=r" (ret)
  61         : "r" (clkid), "r" (ts), "r" (nr)
  62         : "memory");
  63
  64         return ret;
  65 }
  66
  67 static __always_inline u64 __arch_get_hw_counter(s32 clock_mode,
  68                                                  const struct vdso_data *vd)
  69 {
  70         u64 res;
  71
  72         /*
  73          * Core checks for mode already, so this raced against a concurrent
  74          * update. Return something. Core will do another round and then
  75          * see the mode change and fallback to the syscall.
  76          */
  77         if (clock_mode == VDSO_CLOCKMODE_NONE)
  78                 return 0;
  79
  80         /*
  81          * This isb() is required to prevent that the counter value
  82          * is speculated.
  83          */
  84         isb();
  85         asm volatile("mrs %0, cntvct_el0" : "=r" (res) :: "memory");
  86         /*
  87          * This isb() is required to prevent that the seq lock is
  88          * speculated.#
  89          */
  90         isb();
  91
  92         return res;
  93 }
  94
  95 static __always_inline
  96 const struct vdso_data *__arch_get_vdso_data(void)
  97 {
  98         return _vdso_data;
  99 }
 100
 101 #ifdef CONFIG_TIME_NS
 102 static __always_inline
 103 const struct vdso_data *__arch_get_timens_vdso_data(void)
 104 {
 105         return _timens_data;
 106 }
 107 #endif
 108
 109 #endif /* !__ASSEMBLY__ */
 110
 111 #endif /* __ASM_VDSO_GETTIMEOFDAY_H */