ddccf40fe8
The gettimeofday() function in vdso uses the traditional 'timeval' structure layout, which will be incompatible with future versions of glibc on 32-bit architectures that use a 64-bit time_t. This interface is problematic for y2038, when time_t overflows on 32-bit architectures, but the plan so far is that a libc with 64-bit time_t will not call into the gettimeofday() vdso helper at all, and only have a method for entering clock_gettime(). This means we don't have to fix it here, though we probably want to add a new clock_gettime() entry point using a 64-bit version of 'struct timespec' at some point. Changing the vdso code to use __kernel_old_timeval helps isolate this usage from the other ones that still need to be fixed properly, and it gets us closer to removing the 'timeval' definition from the kernel sources. Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
374 lines
9.1 KiB
C
374 lines
9.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Copyright 2006 Andi Kleen, SUSE Labs.
|
|
*
|
|
* Fast user context implementation of clock_gettime, gettimeofday, and time.
|
|
*
|
|
* The code should have no internal unresolved relocations.
|
|
* Check with readelf after changing.
|
|
* Also alternative() doesn't work.
|
|
*/
|
|
/*
|
|
* Copyright (c) 2017 Oracle and/or its affiliates. All rights reserved.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/time.h>
|
|
#include <linux/string.h>
|
|
#include <asm/io.h>
|
|
#include <asm/unistd.h>
|
|
#include <asm/timex.h>
|
|
#include <asm/clocksource.h>
|
|
#include <asm/vvar.h>
|
|
|
|
#ifdef CONFIG_SPARC64
|
|
#define SYSCALL_STRING \
|
|
"ta 0x6d;" \
|
|
"bcs,a 1f;" \
|
|
" sub %%g0, %%o0, %%o0;" \
|
|
"1:"
|
|
#else
|
|
#define SYSCALL_STRING \
|
|
"ta 0x10;" \
|
|
"bcs,a 1f;" \
|
|
" sub %%g0, %%o0, %%o0;" \
|
|
"1:"
|
|
#endif
|
|
|
|
#define SYSCALL_CLOBBERS \
|
|
"f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7", \
|
|
"f8", "f9", "f10", "f11", "f12", "f13", "f14", "f15", \
|
|
"f16", "f17", "f18", "f19", "f20", "f21", "f22", "f23", \
|
|
"f24", "f25", "f26", "f27", "f28", "f29", "f30", "f31", \
|
|
"f32", "f34", "f36", "f38", "f40", "f42", "f44", "f46", \
|
|
"f48", "f50", "f52", "f54", "f56", "f58", "f60", "f62", \
|
|
"cc", "memory"
|
|
|
|
/*
|
|
* Compute the vvar page's address in the process address space, and return it
|
|
* as a pointer to the vvar_data.
|
|
*/
|
|
notrace static __always_inline struct vvar_data *get_vvar_data(void)
|
|
{
|
|
unsigned long ret;
|
|
|
|
/*
|
|
* vdso data page is the first vDSO page so grab the PC
|
|
* and move up a page to get to the data page.
|
|
*/
|
|
__asm__("rd %%pc, %0" : "=r" (ret));
|
|
ret &= ~(8192 - 1);
|
|
ret -= 8192;
|
|
|
|
return (struct vvar_data *) ret;
|
|
}
|
|
|
|
notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
|
|
{
|
|
register long num __asm__("g1") = __NR_clock_gettime;
|
|
register long o0 __asm__("o0") = clock;
|
|
register long o1 __asm__("o1") = (long) ts;
|
|
|
|
__asm__ __volatile__(SYSCALL_STRING : "=r" (o0) : "r" (num),
|
|
"0" (o0), "r" (o1) : SYSCALL_CLOBBERS);
|
|
return o0;
|
|
}
|
|
|
|
notrace static long vdso_fallback_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
|
|
{
|
|
register long num __asm__("g1") = __NR_gettimeofday;
|
|
register long o0 __asm__("o0") = (long) tv;
|
|
register long o1 __asm__("o1") = (long) tz;
|
|
|
|
__asm__ __volatile__(SYSCALL_STRING : "=r" (o0) : "r" (num),
|
|
"0" (o0), "r" (o1) : SYSCALL_CLOBBERS);
|
|
return o0;
|
|
}
|
|
|
|
#ifdef CONFIG_SPARC64
|
|
notrace static __always_inline u64 vread_tick(void)
|
|
{
|
|
u64 ret;
|
|
|
|
__asm__ __volatile__("rd %%tick, %0" : "=r" (ret));
|
|
return ret;
|
|
}
|
|
|
|
notrace static __always_inline u64 vread_tick_stick(void)
|
|
{
|
|
u64 ret;
|
|
|
|
__asm__ __volatile__("rd %%asr24, %0" : "=r" (ret));
|
|
return ret;
|
|
}
|
|
#else
|
|
notrace static __always_inline u64 vread_tick(void)
|
|
{
|
|
register unsigned long long ret asm("o4");
|
|
|
|
__asm__ __volatile__("rd %%tick, %L0\n\t"
|
|
"srlx %L0, 32, %H0"
|
|
: "=r" (ret));
|
|
return ret;
|
|
}
|
|
|
|
notrace static __always_inline u64 vread_tick_stick(void)
|
|
{
|
|
register unsigned long long ret asm("o4");
|
|
|
|
__asm__ __volatile__("rd %%asr24, %L0\n\t"
|
|
"srlx %L0, 32, %H0"
|
|
: "=r" (ret));
|
|
return ret;
|
|
}
|
|
#endif
|
|
|
|
notrace static __always_inline u64 vgetsns(struct vvar_data *vvar)
|
|
{
|
|
u64 v;
|
|
u64 cycles;
|
|
|
|
cycles = vread_tick();
|
|
v = (cycles - vvar->clock.cycle_last) & vvar->clock.mask;
|
|
return v * vvar->clock.mult;
|
|
}
|
|
|
|
notrace static __always_inline u64 vgetsns_stick(struct vvar_data *vvar)
|
|
{
|
|
u64 v;
|
|
u64 cycles;
|
|
|
|
cycles = vread_tick_stick();
|
|
v = (cycles - vvar->clock.cycle_last) & vvar->clock.mask;
|
|
return v * vvar->clock.mult;
|
|
}
|
|
|
|
notrace static __always_inline int do_realtime(struct vvar_data *vvar,
|
|
struct timespec *ts)
|
|
{
|
|
unsigned long seq;
|
|
u64 ns;
|
|
|
|
do {
|
|
seq = vvar_read_begin(vvar);
|
|
ts->tv_sec = vvar->wall_time_sec;
|
|
ns = vvar->wall_time_snsec;
|
|
ns += vgetsns(vvar);
|
|
ns >>= vvar->clock.shift;
|
|
} while (unlikely(vvar_read_retry(vvar, seq)));
|
|
|
|
ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
|
|
ts->tv_nsec = ns;
|
|
|
|
return 0;
|
|
}
|
|
|
|
notrace static __always_inline int do_realtime_stick(struct vvar_data *vvar,
|
|
struct timespec *ts)
|
|
{
|
|
unsigned long seq;
|
|
u64 ns;
|
|
|
|
do {
|
|
seq = vvar_read_begin(vvar);
|
|
ts->tv_sec = vvar->wall_time_sec;
|
|
ns = vvar->wall_time_snsec;
|
|
ns += vgetsns_stick(vvar);
|
|
ns >>= vvar->clock.shift;
|
|
} while (unlikely(vvar_read_retry(vvar, seq)));
|
|
|
|
ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
|
|
ts->tv_nsec = ns;
|
|
|
|
return 0;
|
|
}
|
|
|
|
notrace static __always_inline int do_monotonic(struct vvar_data *vvar,
|
|
struct timespec *ts)
|
|
{
|
|
unsigned long seq;
|
|
u64 ns;
|
|
|
|
do {
|
|
seq = vvar_read_begin(vvar);
|
|
ts->tv_sec = vvar->monotonic_time_sec;
|
|
ns = vvar->monotonic_time_snsec;
|
|
ns += vgetsns(vvar);
|
|
ns >>= vvar->clock.shift;
|
|
} while (unlikely(vvar_read_retry(vvar, seq)));
|
|
|
|
ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
|
|
ts->tv_nsec = ns;
|
|
|
|
return 0;
|
|
}
|
|
|
|
notrace static __always_inline int do_monotonic_stick(struct vvar_data *vvar,
|
|
struct timespec *ts)
|
|
{
|
|
unsigned long seq;
|
|
u64 ns;
|
|
|
|
do {
|
|
seq = vvar_read_begin(vvar);
|
|
ts->tv_sec = vvar->monotonic_time_sec;
|
|
ns = vvar->monotonic_time_snsec;
|
|
ns += vgetsns_stick(vvar);
|
|
ns >>= vvar->clock.shift;
|
|
} while (unlikely(vvar_read_retry(vvar, seq)));
|
|
|
|
ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
|
|
ts->tv_nsec = ns;
|
|
|
|
return 0;
|
|
}
|
|
|
|
notrace static int do_realtime_coarse(struct vvar_data *vvar,
|
|
struct timespec *ts)
|
|
{
|
|
unsigned long seq;
|
|
|
|
do {
|
|
seq = vvar_read_begin(vvar);
|
|
ts->tv_sec = vvar->wall_time_coarse_sec;
|
|
ts->tv_nsec = vvar->wall_time_coarse_nsec;
|
|
} while (unlikely(vvar_read_retry(vvar, seq)));
|
|
return 0;
|
|
}
|
|
|
|
notrace static int do_monotonic_coarse(struct vvar_data *vvar,
|
|
struct timespec *ts)
|
|
{
|
|
unsigned long seq;
|
|
|
|
do {
|
|
seq = vvar_read_begin(vvar);
|
|
ts->tv_sec = vvar->monotonic_time_coarse_sec;
|
|
ts->tv_nsec = vvar->monotonic_time_coarse_nsec;
|
|
} while (unlikely(vvar_read_retry(vvar, seq)));
|
|
|
|
return 0;
|
|
}
|
|
|
|
notrace int
|
|
__vdso_clock_gettime(clockid_t clock, struct timespec *ts)
|
|
{
|
|
struct vvar_data *vvd = get_vvar_data();
|
|
|
|
switch (clock) {
|
|
case CLOCK_REALTIME:
|
|
if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
|
|
break;
|
|
return do_realtime(vvd, ts);
|
|
case CLOCK_MONOTONIC:
|
|
if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
|
|
break;
|
|
return do_monotonic(vvd, ts);
|
|
case CLOCK_REALTIME_COARSE:
|
|
return do_realtime_coarse(vvd, ts);
|
|
case CLOCK_MONOTONIC_COARSE:
|
|
return do_monotonic_coarse(vvd, ts);
|
|
}
|
|
/*
|
|
* Unknown clock ID ? Fall back to the syscall.
|
|
*/
|
|
return vdso_fallback_gettime(clock, ts);
|
|
}
|
|
int
|
|
clock_gettime(clockid_t, struct timespec *)
|
|
__attribute__((weak, alias("__vdso_clock_gettime")));
|
|
|
|
notrace int
|
|
__vdso_clock_gettime_stick(clockid_t clock, struct timespec *ts)
|
|
{
|
|
struct vvar_data *vvd = get_vvar_data();
|
|
|
|
switch (clock) {
|
|
case CLOCK_REALTIME:
|
|
if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
|
|
break;
|
|
return do_realtime_stick(vvd, ts);
|
|
case CLOCK_MONOTONIC:
|
|
if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
|
|
break;
|
|
return do_monotonic_stick(vvd, ts);
|
|
case CLOCK_REALTIME_COARSE:
|
|
return do_realtime_coarse(vvd, ts);
|
|
case CLOCK_MONOTONIC_COARSE:
|
|
return do_monotonic_coarse(vvd, ts);
|
|
}
|
|
/*
|
|
* Unknown clock ID ? Fall back to the syscall.
|
|
*/
|
|
return vdso_fallback_gettime(clock, ts);
|
|
}
|
|
|
|
notrace int
|
|
__vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
|
|
{
|
|
struct vvar_data *vvd = get_vvar_data();
|
|
|
|
if (likely(vvd->vclock_mode != VCLOCK_NONE)) {
|
|
if (likely(tv != NULL)) {
|
|
union tstv_t {
|
|
struct timespec ts;
|
|
struct __kernel_old_timeval tv;
|
|
} *tstv = (union tstv_t *) tv;
|
|
do_realtime(vvd, &tstv->ts);
|
|
/*
|
|
* Assign before dividing to ensure that the division is
|
|
* done in the type of tv_usec, not tv_nsec.
|
|
*
|
|
* There cannot be > 1 billion usec in a second:
|
|
* do_realtime() has already distributed such overflow
|
|
* into tv_sec. So we can assign it to an int safely.
|
|
*/
|
|
tstv->tv.tv_usec = tstv->ts.tv_nsec;
|
|
tstv->tv.tv_usec /= 1000;
|
|
}
|
|
if (unlikely(tz != NULL)) {
|
|
/* Avoid memcpy. Some old compilers fail to inline it */
|
|
tz->tz_minuteswest = vvd->tz_minuteswest;
|
|
tz->tz_dsttime = vvd->tz_dsttime;
|
|
}
|
|
return 0;
|
|
}
|
|
return vdso_fallback_gettimeofday(tv, tz);
|
|
}
|
|
int
|
|
gettimeofday(struct __kernel_old_timeval *, struct timezone *)
|
|
__attribute__((weak, alias("__vdso_gettimeofday")));
|
|
|
|
notrace int
|
|
__vdso_gettimeofday_stick(struct __kernel_old_timeval *tv, struct timezone *tz)
|
|
{
|
|
struct vvar_data *vvd = get_vvar_data();
|
|
|
|
if (likely(vvd->vclock_mode != VCLOCK_NONE)) {
|
|
if (likely(tv != NULL)) {
|
|
union tstv_t {
|
|
struct timespec ts;
|
|
struct __kernel_old_timeval tv;
|
|
} *tstv = (union tstv_t *) tv;
|
|
do_realtime_stick(vvd, &tstv->ts);
|
|
/*
|
|
* Assign before dividing to ensure that the division is
|
|
* done in the type of tv_usec, not tv_nsec.
|
|
*
|
|
* There cannot be > 1 billion usec in a second:
|
|
* do_realtime() has already distributed such overflow
|
|
* into tv_sec. So we can assign it to an int safely.
|
|
*/
|
|
tstv->tv.tv_usec = tstv->ts.tv_nsec;
|
|
tstv->tv.tv_usec /= 1000;
|
|
}
|
|
if (unlikely(tz != NULL)) {
|
|
/* Avoid memcpy. Some old compilers fail to inline it */
|
|
tz->tz_minuteswest = vvd->tz_minuteswest;
|
|
tz->tz_dsttime = vvd->tz_dsttime;
|
|
}
|
|
return 0;
|
|
}
|
|
return vdso_fallback_gettimeofday(tv, tz);
|
|
}
|