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/unistd.h>
  11 #include <uapi/linux/time.h>
  12
  13 #define __VDSO_USE_SYSCALL              ULLONG_MAX
  14
  15 #define VDSO_HAS_CLOCK_GETRES           1
  16
  17 static __always_inline
  18 int gettimeofday_fallback(struct __kernel_old_timeval *_tv,
  19                           struct timezone *_tz)
  20 {
  21         register struct timezone *tz asm("x1") = _tz;
  22         register struct __kernel_old_timeval *tv asm("x0") = _tv;
  23         register long ret asm ("x0");
  24         register long nr asm("x8") = __NR_gettimeofday;
  25
  26         asm volatile(
  27         "       svc #0\n"
  28         : "=r" (ret)
  29         : "r" (tv), "r" (tz), "r" (nr)
  30         : "memory");
  31
  32         return ret;
  33 }
  34
  35 static __always_inline
  36 long clock_gettime_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
  37 {
  38         register struct __kernel_timespec *ts asm("x1") = _ts;
  39         register clockid_t clkid asm("x0") = _clkid;
  40         register long ret asm ("x0");
  41         register long nr asm("x8") = __NR_clock_gettime;
  42
  43         asm volatile(
  44         "       svc #0\n"
  45         : "=r" (ret)
  46         : "r" (clkid), "r" (ts), "r" (nr)
  47         : "memory");
  48
  49         return ret;
  50 }
  51
  52 static __always_inline
  53 int clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
  54 {
  55         register struct __kernel_timespec *ts asm("x1") = _ts;
  56         register clockid_t clkid asm("x0") = _clkid;
  57         register long ret asm ("x0");
  58         register long nr asm("x8") = __NR_clock_getres;
  59
  60         asm volatile(
  61         "       svc #0\n"
  62         : "=r" (ret)
  63         : "r" (clkid), "r" (ts), "r" (nr)
  64         : "memory");
  65
  66         return ret;
  67 }
  68
  69 static __always_inline u64 __arch_get_hw_counter(s32 clock_mode)
  70 {
  71         u64 res;
  72
  73         /*
  74          * clock_mode == 0 implies that vDSO are enabled otherwise
  75          * fallback on syscall.
  76          */
  77         if (clock_mode)
  78                 return __VDSO_USE_SYSCALL;
  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 #endif /* !__ASSEMBLY__ */
 102
 103 #endif /* __ASM_VDSO_GETTIMEOFDAY_H */