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// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2005-2017 Andes Technology Corporation
#include <linux/compiler.h>
#include <linux/hrtimer.h>
#include <linux/time.h>
#include <asm/io.h>
#include <asm/barrier.h>
#include <asm/bug.h>
#include <asm/page.h>
#include <asm/unistd.h>
#include <asm/vdso_datapage.h>
#include <asm/vdso_timer_info.h>
#include <asm/asm-offsets.h>
#define X(x) #x
#define Y(x) X(x)
extern struct vdso_data *__get_datapage(void);
extern struct vdso_data *__get_timerpage(void);
static notrace unsigned int __vdso_read_begin(const struct vdso_data *vdata)
{
u32 seq;
repeat:
seq = READ_ONCE(vdata->seq_count);
if (seq & 1) {
cpu_relax();
goto repeat;
}
return seq;
}
static notrace unsigned int vdso_read_begin(const struct vdso_data *vdata)
{
unsigned int seq;
seq = __vdso_read_begin(vdata);
smp_rmb(); /* Pairs with smp_wmb in vdso_write_end */
return seq;
}
static notrace int vdso_read_retry(const struct vdso_data *vdata, u32 start)
{
smp_rmb(); /* Pairs with smp_wmb in vdso_write_begin */
return vdata->seq_count != start;
}
static notrace long clock_gettime_fallback(clockid_t _clkid,
struct __kernel_old_timespec *_ts)
{
register struct __kernel_old_timespec *ts asm("$r1") = _ts;
register clockid_t clkid asm("$r0") = _clkid;
register long ret asm("$r0");
asm volatile ("movi $r15, %3\n"
"syscall 0x0\n"
:"=r" (ret)
:"r"(clkid), "r"(ts), "i"(__NR_clock_gettime)
:"$r15", "memory");
return ret;
}
static notrace int do_realtime_coarse(struct __kernel_old_timespec *ts,
struct vdso_data *vdata)
{
u32 seq;
do {
seq = vdso_read_begin(vdata);
ts->tv_sec = vdata->xtime_coarse_sec;
ts->tv_nsec = vdata->xtime_coarse_nsec;
} while (vdso_read_retry(vdata, seq));
return 0;
}
static notrace int do_monotonic_coarse(struct __kernel_old_timespec *ts,
struct vdso_data *vdata)
{
struct timespec tomono;
u32 seq;
do {
seq = vdso_read_begin(vdata);
ts->tv_sec = vdata->xtime_coarse_sec;
ts->tv_nsec = vdata->xtime_coarse_nsec;
tomono.tv_sec = vdata->wtm_clock_sec;
tomono.tv_nsec = vdata->wtm_clock_nsec;
} while (vdso_read_retry(vdata, seq));
ts->tv_sec += tomono.tv_sec;
timespec_add_ns(ts, tomono.tv_nsec);
return 0;
}
static notrace inline u64 vgetsns(struct vdso_data *vdso)
{
u32 cycle_now;
u32 cycle_delta;
u32 *timer_cycle_base;
timer_cycle_base =
(u32 *) ((char *)__get_timerpage() + vdso->cycle_count_offset);
cycle_now = readl_relaxed(timer_cycle_base);
if (true == vdso->cycle_count_down)
cycle_now = ~(*timer_cycle_base);
cycle_delta = cycle_now - (u32) vdso->cs_cycle_last;
return ((u64) cycle_delta & vdso->cs_mask) * vdso->cs_mult;
}
static notrace int do_realtime(struct __kernel_old_timespec *ts, struct vdso_data *vdata)
{
unsigned count;
u64 ns;
do {
count = vdso_read_begin(vdata);
ts->tv_sec = vdata->xtime_clock_sec;
ns = vdata->xtime_clock_nsec;
ns += vgetsns(vdata);
ns >>= vdata->cs_shift;
} while (vdso_read_retry(vdata, count));
ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
ts->tv_nsec = ns;
return 0;
}
static notrace int do_monotonic(struct __kernel_old_timespec *ts, struct vdso_data *vdata)
{
struct timespec tomono;
u64 nsecs;
u32 seq;
do {
seq = vdso_read_begin(vdata);
ts->tv_sec = vdata->xtime_clock_sec;
nsecs = vdata->xtime_clock_nsec;
nsecs += vgetsns(vdata);
nsecs >>= vdata->cs_shift;
tomono.tv_sec = vdata->wtm_clock_sec;
tomono.tv_nsec = vdata->wtm_clock_nsec;
} while (vdso_read_retry(vdata, seq));
ts->tv_sec += tomono.tv_sec;
ts->tv_nsec = 0;
timespec_add_ns(ts, nsecs + tomono.tv_nsec);
return 0;
}
notrace int __vdso_clock_gettime(clockid_t clkid, struct __kernel_old_timespec *ts)
{
struct vdso_data *vdata;
int ret = -1;
vdata = __get_datapage();
if (vdata->cycle_count_offset == EMPTY_REG_OFFSET)
return clock_gettime_fallback(clkid, ts);
switch (clkid) {
case CLOCK_REALTIME_COARSE:
ret = do_realtime_coarse(ts, vdata);
break;
case CLOCK_MONOTONIC_COARSE:
ret = do_monotonic_coarse(ts, vdata);
break;
case CLOCK_REALTIME:
ret = do_realtime(ts, vdata);
break;
case CLOCK_MONOTONIC:
ret = do_monotonic(ts, vdata);
break;
default:
break;
}
if (ret)
ret = clock_gettime_fallback(clkid, ts);
return ret;
}
static notrace int clock_getres_fallback(clockid_t _clk_id,
struct __kernel_old_timespec *_res)
{
register clockid_t clk_id asm("$r0") = _clk_id;
register struct __kernel_old_timespec *res asm("$r1") = _res;
register int ret asm("$r0");
asm volatile ("movi $r15, %3\n"
"syscall 0x0\n"
:"=r" (ret)
:"r"(clk_id), "r"(res), "i"(__NR_clock_getres)
:"$r15", "memory");
return ret;
}
notrace int __vdso_clock_getres(clockid_t clk_id, struct __kernel_old_timespec *res)
{
struct vdso_data *vdata = __get_datapage();
if (res == NULL)
return 0;
switch (clk_id) {
case CLOCK_REALTIME:
case CLOCK_MONOTONIC:
case CLOCK_MONOTONIC_RAW:
res->tv_sec = 0;
res->tv_nsec = vdata->hrtimer_res;
break;
case CLOCK_REALTIME_COARSE:
case CLOCK_MONOTONIC_COARSE:
res->tv_sec = 0;
res->tv_nsec = CLOCK_COARSE_RES;
break;
default:
return clock_getres_fallback(clk_id, res);
}
return 0;
}
static notrace inline int gettimeofday_fallback(struct __kernel_old_timeval *_tv,
struct timezone *_tz)
{
register struct __kernel_old_timeval *tv asm("$r0") = _tv;
register struct timezone *tz asm("$r1") = _tz;
register int ret asm("$r0");
asm volatile ("movi $r15, %3\n"
"syscall 0x0\n"
:"=r" (ret)
:"r"(tv), "r"(tz), "i"(__NR_gettimeofday)
:"$r15", "memory");
return ret;
}
notrace int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
{
struct __kernel_old_timespec ts;
struct vdso_data *vdata;
int ret;
vdata = __get_datapage();
if (vdata->cycle_count_offset == EMPTY_REG_OFFSET)
return gettimeofday_fallback(tv, tz);
ret = do_realtime(&ts, vdata);
if (tv) {
tv->tv_sec = ts.tv_sec;
tv->tv_usec = ts.tv_nsec / 1000;
}
if (tz) {
tz->tz_minuteswest = vdata->tz_minuteswest;
tz->tz_dsttime = vdata->tz_dsttime;
}
return ret;
}
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