/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright (C) 2018 ARM Limited
 */
#ifndef __ASM_VDSO_COMPAT_GETTIMEOFDAY_H
#define __ASM_VDSO_COMPAT_GETTIMEOFDAY_H

#ifndef __ASSEMBLER__

#include <asm/barrier.h>
#include <asm/unistd_compat_32.h>
#include <asm/errno.h>

#include <asm/vdso/compat_barrier.h>

#define VDSO_HAS_CLOCK_GETRES           1

#define BUILD_VDSO32                    1

static __always_inline
int gettimeofday_fallback(struct __kernel_old_timeval *_tv,
                          struct timezone *_tz)
{
        register struct timezone *tz asm("r1") = _tz;
        register struct __kernel_old_timeval *tv asm("r0") = _tv;
        register long ret asm ("r0");
        register long nr asm("r7") = __NR_compat32_gettimeofday;

        asm volatile(
        "       swi #0\n"
        : "=r" (ret)
        : "r" (tv), "r" (tz), "r" (nr)
        : "memory");

        return ret;
}

static __always_inline
long clock_gettime_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
{
        register struct __kernel_timespec *ts asm("r1") = _ts;
        register clockid_t clkid asm("r0") = _clkid;
        register long ret asm ("r0");
        register long nr asm("r7") = __NR_compat32_clock_gettime64;

        asm volatile(
        "       swi #0\n"
        : "=r" (ret)
        : "r" (clkid), "r" (ts), "r" (nr)
        : "memory");

        return ret;
}

static __always_inline
long clock_gettime32_fallback(clockid_t _clkid, struct old_timespec32 *_ts)
{
        register struct old_timespec32 *ts asm("r1") = _ts;
        register clockid_t clkid asm("r0") = _clkid;
        register long ret asm ("r0");
        register long nr asm("r7") = __NR_compat32_clock_gettime;

        asm volatile(
        "       swi #0\n"
        : "=r" (ret)
        : "r" (clkid), "r" (ts), "r" (nr)
        : "memory");

        return ret;
}

static __always_inline
int clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
{
        register struct __kernel_timespec *ts asm("r1") = _ts;
        register clockid_t clkid asm("r0") = _clkid;
        register long ret asm ("r0");
        register long nr asm("r7") = __NR_compat32_clock_getres_time64;

        asm volatile(
        "       swi #0\n"
        : "=r" (ret)
        : "r" (clkid), "r" (ts), "r" (nr)
        : "memory");

        return ret;
}

static __always_inline
int clock_getres32_fallback(clockid_t _clkid, struct old_timespec32 *_ts)
{
        register struct old_timespec32 *ts asm("r1") = _ts;
        register clockid_t clkid asm("r0") = _clkid;
        register long ret asm ("r0");
        register long nr asm("r7") = __NR_compat32_clock_getres;

        asm volatile(
        "       swi #0\n"
        : "=r" (ret)
        : "r" (clkid), "r" (ts), "r" (nr)
        : "memory");

        return ret;
}

static __always_inline u64 __arch_get_hw_counter(s32 clock_mode,
                                                 const struct vdso_time_data *vd)
{
        u64 res;

        /*
         * Core checks for mode already, so this raced against a concurrent
         * update. Return something. Core will do another round and then
         * see the mode change and fallback to the syscall.
         */
        if (clock_mode != VDSO_CLOCKMODE_ARCHTIMER)
                return 0;

        /*
         * This isb() is required to prevent that the counter value
         * is speculated.
         */
        isb();
        asm volatile("mrrc p15, 1, %Q0, %R0, c14" : "=r" (res));
        /*
         * This isb() is required to prevent that the seq lock is
         * speculated.
         */
        isb();

        return res;
}

static __always_inline const struct vdso_time_data *__arch_get_vdso_u_time_data(void)
{
        const struct vdso_time_data *ret;

        /*
         * This simply puts &_vdso_time_data into ret. The reason why we don't use
         * `ret = _vdso_time_data` is that the compiler tends to optimise this in a
         * very suboptimal way: instead of keeping &_vdso_time_data in a register,
         * it goes through a relocation almost every time _vdso_time_data must be
         * accessed (even in subfunctions). This is both time and space
         * consuming: each relocation uses a word in the code section, and it
         * has to be loaded at runtime.
         *
         * This trick hides the assignment from the compiler. Since it cannot
         * track where the pointer comes from, it will only use one relocation
         * where __aarch64_get_vdso_u_time_data() is called, and then keep the
         * result in a register.
         */
        asm volatile("mov %0, %1" : "=r"(ret) : "r"(&vdso_u_time_data));

        return ret;
}
#define __arch_get_vdso_u_time_data __arch_get_vdso_u_time_data

static inline bool vdso_clocksource_ok(const struct vdso_clock *vc)
{
        return vc->clock_mode == VDSO_CLOCKMODE_ARCHTIMER;
}
#define vdso_clocksource_ok     vdso_clocksource_ok

#endif /* !__ASSEMBLER__ */

#endif /* __ASM_VDSO_COMPAT_GETTIMEOFDAY_H */