6909e29fde
kdb is the only user of the __current_kernel_time() interface, which is not y2038 safe and should be removed at some point. The kdb code also goes to great lengths to print the time in a human-readable format from 'struct timespec', again using a non-y2038-safe re-implementation of the generic time_to_tm() code. Using __current_kernel_time() here is necessary since the regular accessors that require a sequence lock might hang when called during the xtime update. However, this is safe in the particular case since kdb is only interested in the tv_sec field that is updated atomically. In order to make this y2038-safe, I'm converting the code to the generic time64_to_tm helper, but that introduces the problem that we have no interface like __current_kernel_time() that provides a 64-bit timestamp in a lockless, safe and architecture-independent way. I have multiple ideas for how to solve that: - __ktime_get_real_seconds() is lockless, but can return incorrect results on 32-bit architectures in the special case that we are in the process of changing the time across the epoch, either during the timer tick that overflows the seconds in 2038, or while calling settimeofday. - ktime_get_real_fast_ns() would work in this context, but does require a call into the clocksource driver to return a high-resolution timestamp. This may have undesired side-effects in the debugger, since we want to limit the interactions with the rest of the kernel. - Adding a ktime_get_real_fast_seconds() based on tk_fast_mono plus tkr->base_real without the tk_clock_read() delta. Not sure about the value of adding yet another interface here. - Changing the existing ktime_get_real_seconds() to use tk_fast_mono on 32-bit architectures rather than xtime_sec. I think this could work, but am not entirely sure if this is an improvement. I picked the first of those for simplicity here. It's technically not correct but probably good enough as the time is only used for the debugging output and the race will likely never be hit in practice. Another downside is having to move the declaration into a public header file. Let me know if anyone has a different preference. Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://patchwork.kernel.org/patch/9775309/ Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
215 lines
5.2 KiB
C
215 lines
5.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _LINUX_TIMEKEEPING_H
|
|
#define _LINUX_TIMEKEEPING_H
|
|
|
|
#include <linux/errno.h>
|
|
|
|
/* Included from linux/ktime.h */
|
|
|
|
void timekeeping_init(void);
|
|
extern int timekeeping_suspended;
|
|
|
|
/* Architecture timer tick functions: */
|
|
extern void update_process_times(int user);
|
|
extern void xtime_update(unsigned long ticks);
|
|
|
|
/*
|
|
* Get and set timeofday
|
|
*/
|
|
extern int do_settimeofday64(const struct timespec64 *ts);
|
|
extern int do_sys_settimeofday64(const struct timespec64 *tv,
|
|
const struct timezone *tz);
|
|
/*
|
|
* Kernel time accessors
|
|
*/
|
|
struct timespec64 current_kernel_time64(void);
|
|
|
|
/*
|
|
* timespec64 based interfaces
|
|
*/
|
|
struct timespec64 get_monotonic_coarse64(void);
|
|
extern void getrawmonotonic64(struct timespec64 *ts);
|
|
extern void ktime_get_ts64(struct timespec64 *ts);
|
|
extern time64_t ktime_get_seconds(void);
|
|
extern time64_t __ktime_get_real_seconds(void);
|
|
extern time64_t ktime_get_real_seconds(void);
|
|
|
|
extern int __getnstimeofday64(struct timespec64 *tv);
|
|
extern void getnstimeofday64(struct timespec64 *tv);
|
|
extern void getboottime64(struct timespec64 *ts);
|
|
|
|
#define ktime_get_real_ts64(ts) getnstimeofday64(ts)
|
|
|
|
/*
|
|
* ktime_t based interfaces
|
|
*/
|
|
|
|
enum tk_offsets {
|
|
TK_OFFS_REAL,
|
|
TK_OFFS_BOOT,
|
|
TK_OFFS_TAI,
|
|
TK_OFFS_MAX,
|
|
};
|
|
|
|
extern ktime_t ktime_get(void);
|
|
extern ktime_t ktime_get_with_offset(enum tk_offsets offs);
|
|
extern ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs);
|
|
extern ktime_t ktime_get_raw(void);
|
|
extern u32 ktime_get_resolution_ns(void);
|
|
|
|
/**
|
|
* ktime_get_real - get the real (wall-) time in ktime_t format
|
|
*/
|
|
static inline ktime_t ktime_get_real(void)
|
|
{
|
|
return ktime_get_with_offset(TK_OFFS_REAL);
|
|
}
|
|
|
|
/**
|
|
* ktime_get_boottime - Returns monotonic time since boot in ktime_t format
|
|
*
|
|
* This is similar to CLOCK_MONTONIC/ktime_get, but also includes the
|
|
* time spent in suspend.
|
|
*/
|
|
static inline ktime_t ktime_get_boottime(void)
|
|
{
|
|
return ktime_get_with_offset(TK_OFFS_BOOT);
|
|
}
|
|
|
|
/**
|
|
* ktime_get_clocktai - Returns the TAI time of day in ktime_t format
|
|
*/
|
|
static inline ktime_t ktime_get_clocktai(void)
|
|
{
|
|
return ktime_get_with_offset(TK_OFFS_TAI);
|
|
}
|
|
|
|
/**
|
|
* ktime_mono_to_real - Convert monotonic time to clock realtime
|
|
*/
|
|
static inline ktime_t ktime_mono_to_real(ktime_t mono)
|
|
{
|
|
return ktime_mono_to_any(mono, TK_OFFS_REAL);
|
|
}
|
|
|
|
static inline u64 ktime_get_ns(void)
|
|
{
|
|
return ktime_to_ns(ktime_get());
|
|
}
|
|
|
|
static inline u64 ktime_get_real_ns(void)
|
|
{
|
|
return ktime_to_ns(ktime_get_real());
|
|
}
|
|
|
|
static inline u64 ktime_get_boot_ns(void)
|
|
{
|
|
return ktime_to_ns(ktime_get_boottime());
|
|
}
|
|
|
|
static inline u64 ktime_get_tai_ns(void)
|
|
{
|
|
return ktime_to_ns(ktime_get_clocktai());
|
|
}
|
|
|
|
static inline u64 ktime_get_raw_ns(void)
|
|
{
|
|
return ktime_to_ns(ktime_get_raw());
|
|
}
|
|
|
|
extern u64 ktime_get_mono_fast_ns(void);
|
|
extern u64 ktime_get_raw_fast_ns(void);
|
|
extern u64 ktime_get_boot_fast_ns(void);
|
|
extern u64 ktime_get_real_fast_ns(void);
|
|
|
|
/*
|
|
* timespec64 interfaces utilizing the ktime based ones
|
|
*/
|
|
static inline void get_monotonic_boottime64(struct timespec64 *ts)
|
|
{
|
|
*ts = ktime_to_timespec64(ktime_get_boottime());
|
|
}
|
|
|
|
static inline void timekeeping_clocktai64(struct timespec64 *ts)
|
|
{
|
|
*ts = ktime_to_timespec64(ktime_get_clocktai());
|
|
}
|
|
|
|
/*
|
|
* RTC specific
|
|
*/
|
|
extern bool timekeeping_rtc_skipsuspend(void);
|
|
extern bool timekeeping_rtc_skipresume(void);
|
|
|
|
extern void timekeeping_inject_sleeptime64(struct timespec64 *delta);
|
|
|
|
/*
|
|
* struct system_time_snapshot - simultaneous raw/real time capture with
|
|
* counter value
|
|
* @cycles: Clocksource counter value to produce the system times
|
|
* @real: Realtime system time
|
|
* @raw: Monotonic raw system time
|
|
* @clock_was_set_seq: The sequence number of clock was set events
|
|
* @cs_was_changed_seq: The sequence number of clocksource change events
|
|
*/
|
|
struct system_time_snapshot {
|
|
u64 cycles;
|
|
ktime_t real;
|
|
ktime_t raw;
|
|
unsigned int clock_was_set_seq;
|
|
u8 cs_was_changed_seq;
|
|
};
|
|
|
|
/*
|
|
* struct system_device_crosststamp - system/device cross-timestamp
|
|
* (syncronized capture)
|
|
* @device: Device time
|
|
* @sys_realtime: Realtime simultaneous with device time
|
|
* @sys_monoraw: Monotonic raw simultaneous with device time
|
|
*/
|
|
struct system_device_crosststamp {
|
|
ktime_t device;
|
|
ktime_t sys_realtime;
|
|
ktime_t sys_monoraw;
|
|
};
|
|
|
|
/*
|
|
* struct system_counterval_t - system counter value with the pointer to the
|
|
* corresponding clocksource
|
|
* @cycles: System counter value
|
|
* @cs: Clocksource corresponding to system counter value. Used by
|
|
* timekeeping code to verify comparibility of two cycle values
|
|
*/
|
|
struct system_counterval_t {
|
|
u64 cycles;
|
|
struct clocksource *cs;
|
|
};
|
|
|
|
/*
|
|
* Get cross timestamp between system clock and device clock
|
|
*/
|
|
extern int get_device_system_crosststamp(
|
|
int (*get_time_fn)(ktime_t *device_time,
|
|
struct system_counterval_t *system_counterval,
|
|
void *ctx),
|
|
void *ctx,
|
|
struct system_time_snapshot *history,
|
|
struct system_device_crosststamp *xtstamp);
|
|
|
|
/*
|
|
* Simultaneously snapshot realtime and monotonic raw clocks
|
|
*/
|
|
extern void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot);
|
|
|
|
/*
|
|
* Persistent clock related interfaces
|
|
*/
|
|
extern int persistent_clock_is_local;
|
|
|
|
extern void read_persistent_clock64(struct timespec64 *ts);
|
|
extern void read_boot_clock64(struct timespec64 *ts);
|
|
extern int update_persistent_clock64(struct timespec64 now);
|
|
|
|
|
|
#endif
|