LXR linux/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
  15static __always_inline
  16int 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
  33static __always_inline
  34long 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
  50static __always_inline
  51int 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
  67static __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
  95static __always_inline
  96const struct vdso_data *__arch_get_vdso_data(void)
  97{
  98        return _vdso_data;
  99}
 100
 101#ifdef CONFIG_TIME_NS
 102static __always_inline
 103const 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 */
 112