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time: Add y2038 safe read_persistent_clock64()

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As part of addressing in-kernel y2038 issues, this patch adds
read_persistent_clock64() and replaces all the call sites of
read_persistent_clock() with this function. This is a __weak
implementation, which simply calls the existing y2038 unsafe
read_persistent_clock().

This allows architecture specific implementations to be
converted independently, and eventually the y2038 unsafe
read_persistent_clock() can be removed after all its
architecture specific implementations have been converted to
read_persistent_clock64().

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1427945681-29972-3-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Xunlei Pang 2015-04-01 20:34:22 -07:00 committed by Ingo Molnar
parent 9a806ddbb9
commit 2ee9663200
3 changed files with 15 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
arch/mips/lasat/sysctl.c
View File

@ -75,11 +75,11 @@ static int rtctmp;
int proc_dolasatrtc(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct timespec ts;
struct timespec64 ts;
int r;
if (!write) {
read_persistent_clock(&ts);
read_persistent_clock64(&ts);
rtctmp = ts.tv_sec;
/* check for time < 0 and set to 0 */
if (rtctmp < 0)

1
include/linux/timekeeping.h
View File

@ -268,6 +268,7 @@ static inline bool has_persistent_clock(void)
}
extern void read_persistent_clock(struct timespec *ts);
extern void read_persistent_clock64(struct timespec64 *ts);
extern void read_boot_clock(struct timespec *ts);
extern void read_boot_clock64(struct timespec64 *ts);
extern int update_persistent_clock(struct timespec now);

22
kernel/time/timekeeping.c
View File

@ -1173,6 +1173,14 @@ void __weak read_persistent_clock(struct timespec *ts)
ts->tv_nsec = 0;
}
void __weak read_persistent_clock64(struct timespec64 *ts64)
{
struct timespec ts;
read_persistent_clock(&ts);
*ts64 = timespec_to_timespec64(ts);
}
/**
* read_boot_clock - Return time of the system start.
*
@ -1205,10 +1213,8 @@ void __init timekeeping_init(void)
struct clocksource *clock;
unsigned long flags;
struct timespec64 now, boot, tmp;
struct timespec ts;
read_persistent_clock(&ts);
now = timespec_to_timespec64(ts);
read_persistent_clock64(&now);
if (!timespec64_valid_strict(&now)) {
pr_warn("WARNING: Persistent clock returned invalid value!\n"
" Check your CMOS/BIOS settings.\n");
@ -1278,7 +1284,7 @@ static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
* timekeeping_inject_sleeptime64 - Adds suspend interval to timeekeeping values
* @delta: pointer to a timespec64 delta value
*
* This hook is for architectures that cannot support read_persistent_clock
* This hook is for architectures that cannot support read_persistent_clock64
* because their RTC/persistent clock is only accessible when irqs are enabled.
*
* This function should only be called by rtc_resume(), and allows
@ -1325,12 +1331,10 @@ void timekeeping_resume(void)
struct clocksource *clock = tk->tkr_mono.clock;
unsigned long flags;
struct timespec64 ts_new, ts_delta;
struct timespec tmp;
cycle_t cycle_now, cycle_delta;
bool suspendtime_found = false;
read_persistent_clock(&tmp);
ts_new = timespec_to_timespec64(tmp);
read_persistent_clock64(&ts_new);
clockevents_resume();
clocksource_resume();
@ -1406,10 +1410,8 @@ int timekeeping_suspend(void)
unsigned long flags;
struct timespec64 delta, delta_delta;
static struct timespec64 old_delta;
struct timespec tmp;
read_persistent_clock(&tmp);
timekeeping_suspend_time = timespec_to_timespec64(tmp);
read_persistent_clock64(&timekeeping_suspend_time);
/*
* On some systems the persistent_clock can not be detected at