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-rw-r--r--kernel/time/timekeeping.c182
1 files changed, 161 insertions, 21 deletions
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 2cafb49aa65e..198afa78bf69 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -60,8 +60,27 @@ struct tk_fast {
struct tk_read_base base[2];
};
-static struct tk_fast tk_fast_mono ____cacheline_aligned;
-static struct tk_fast tk_fast_raw ____cacheline_aligned;
+/* Suspend-time cycles value for halted fast timekeeper. */
+static u64 cycles_at_suspend;
+
+static u64 dummy_clock_read(struct clocksource *cs)
+{
+ return cycles_at_suspend;
+}
+
+static struct clocksource dummy_clock = {
+ .read = dummy_clock_read,
+};
+
+static struct tk_fast tk_fast_mono ____cacheline_aligned = {
+ .base[0] = { .clock = &dummy_clock, },
+ .base[1] = { .clock = &dummy_clock, },
+};
+
+static struct tk_fast tk_fast_raw ____cacheline_aligned = {
+ .base[0] = { .clock = &dummy_clock, },
+ .base[1] = { .clock = &dummy_clock, },
+};
/* flag for if timekeeping is suspended */
int __read_mostly timekeeping_suspended;
@@ -477,17 +496,39 @@ u64 notrace ktime_get_boot_fast_ns(void)
}
EXPORT_SYMBOL_GPL(ktime_get_boot_fast_ns);
-/* Suspend-time cycles value for halted fast timekeeper. */
-static u64 cycles_at_suspend;
-static u64 dummy_clock_read(struct clocksource *cs)
+/*
+ * See comment for __ktime_get_fast_ns() vs. timestamp ordering
+ */
+static __always_inline u64 __ktime_get_real_fast_ns(struct tk_fast *tkf)
{
- return cycles_at_suspend;
+ struct tk_read_base *tkr;
+ unsigned int seq;
+ u64 now;
+
+ do {
+ seq = raw_read_seqcount_latch(&tkf->seq);
+ tkr = tkf->base + (seq & 0x01);
+ now = ktime_to_ns(tkr->base_real);
+
+ now += timekeeping_delta_to_ns(tkr,
+ clocksource_delta(
+ tk_clock_read(tkr),
+ tkr->cycle_last,
+ tkr->mask));
+ } while (read_seqcount_retry(&tkf->seq, seq));
+
+ return now;
}
-static struct clocksource dummy_clock = {
- .read = dummy_clock_read,
-};
+/**
+ * ktime_get_real_fast_ns: - NMI safe and fast access to clock realtime.
+ */
+u64 ktime_get_real_fast_ns(void)
+{
+ return __ktime_get_real_fast_ns(&tk_fast_mono);
+}
+EXPORT_SYMBOL_GPL(ktime_get_real_fast_ns);
/**
* halt_fast_timekeeper - Prevent fast timekeeper from accessing clocksource.
@@ -507,6 +548,7 @@ static void halt_fast_timekeeper(struct timekeeper *tk)
memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
cycles_at_suspend = tk_clock_read(tkr);
tkr_dummy.clock = &dummy_clock;
+ tkr_dummy.base_real = tkr->base + tk->offs_real;
update_fast_timekeeper(&tkr_dummy, &tk_fast_mono);
tkr = &tk->tkr_raw;
@@ -654,6 +696,7 @@ static void timekeeping_update(struct timekeeper *tk, unsigned int action)
update_vsyscall(tk);
update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);
+ tk->tkr_mono.base_real = tk->tkr_mono.base + tk->offs_real;
update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
update_fast_timekeeper(&tk->tkr_raw, &tk_fast_raw);
@@ -1264,33 +1307,31 @@ EXPORT_SYMBOL(do_settimeofday64);
*
* Adds or subtracts an offset value from the current time.
*/
-int timekeeping_inject_offset(struct timespec *ts)
+static int timekeeping_inject_offset(struct timespec64 *ts)
{
struct timekeeper *tk = &tk_core.timekeeper;
unsigned long flags;
- struct timespec64 ts64, tmp;
+ struct timespec64 tmp;
int ret = 0;
- if (!timespec_inject_offset_valid(ts))
+ if (ts->tv_nsec < 0 || ts->tv_nsec >= NSEC_PER_SEC)
return -EINVAL;
- ts64 = timespec_to_timespec64(*ts);
-
raw_spin_lock_irqsave(&timekeeper_lock, flags);
write_seqcount_begin(&tk_core.seq);
timekeeping_forward_now(tk);
/* Make sure the proposed value is valid */
- tmp = timespec64_add(tk_xtime(tk), ts64);
- if (timespec64_compare(&tk->wall_to_monotonic, &ts64) > 0 ||
+ tmp = timespec64_add(tk_xtime(tk), *ts);
+ if (timespec64_compare(&tk->wall_to_monotonic, ts) > 0 ||
!timespec64_valid_strict(&tmp)) {
ret = -EINVAL;
goto error;
}
- tk_xtime_add(tk, &ts64);
- tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts64));
+ tk_xtime_add(tk, ts);
+ tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *ts));
error: /* even if we error out, we forwarded the time, so call update */
timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
@@ -1303,7 +1344,40 @@ error: /* even if we error out, we forwarded the time, so call update */
return ret;
}
-EXPORT_SYMBOL(timekeeping_inject_offset);
+
+/*
+ * Indicates if there is an offset between the system clock and the hardware
+ * clock/persistent clock/rtc.
+ */
+int persistent_clock_is_local;
+
+/*
+ * Adjust the time obtained from the CMOS to be UTC time instead of
+ * local time.
+ *
+ * This is ugly, but preferable to the alternatives. Otherwise we
+ * would either need to write a program to do it in /etc/rc (and risk
+ * confusion if the program gets run more than once; it would also be
+ * hard to make the program warp the clock precisely n hours) or
+ * compile in the timezone information into the kernel. Bad, bad....
+ *
+ * - TYT, 1992-01-01
+ *
+ * The best thing to do is to keep the CMOS clock in universal time (UTC)
+ * as real UNIX machines always do it. This avoids all headaches about
+ * daylight saving times and warping kernel clocks.
+ */
+void timekeeping_warp_clock(void)
+{
+ if (sys_tz.tz_minuteswest != 0) {
+ struct timespec64 adjust;
+
+ persistent_clock_is_local = 1;
+ adjust.tv_sec = sys_tz.tz_minuteswest * 60;
+ adjust.tv_nsec = 0;
+ timekeeping_inject_offset(&adjust);
+ }
+}
/**
* __timekeeping_set_tai_offset - Sets the TAI offset from UTC and monotonic
@@ -2248,6 +2322,72 @@ ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq, ktime_t *offs_real,
}
/**
+ * timekeeping_validate_timex - Ensures the timex is ok for use in do_adjtimex
+ */
+static int timekeeping_validate_timex(struct timex *txc)
+{
+ if (txc->modes & ADJ_ADJTIME) {
+ /* singleshot must not be used with any other mode bits */
+ if (!(txc->modes & ADJ_OFFSET_SINGLESHOT))
+ return -EINVAL;
+ if (!(txc->modes & ADJ_OFFSET_READONLY) &&
+ !capable(CAP_SYS_TIME))
+ return -EPERM;
+ } else {
+ /* In order to modify anything, you gotta be super-user! */
+ if (txc->modes && !capable(CAP_SYS_TIME))
+ return -EPERM;
+ /*
+ * if the quartz is off by more than 10% then
+ * something is VERY wrong!
+ */
+ if (txc->modes & ADJ_TICK &&
+ (txc->tick < 900000/USER_HZ ||
+ txc->tick > 1100000/USER_HZ))
+ return -EINVAL;
+ }
+
+ if (txc->modes & ADJ_SETOFFSET) {
+ /* In order to inject time, you gotta be super-user! */
+ if (!capable(CAP_SYS_TIME))
+ return -EPERM;
+
+ /*
+ * Validate if a timespec/timeval used to inject a time
+ * offset is valid. Offsets can be postive or negative, so
+ * we don't check tv_sec. The value of the timeval/timespec
+ * is the sum of its fields,but *NOTE*:
+ * The field tv_usec/tv_nsec must always be non-negative and
+ * we can't have more nanoseconds/microseconds than a second.
+ */
+ if (txc->time.tv_usec < 0)
+ return -EINVAL;
+
+ if (txc->modes & ADJ_NANO) {
+ if (txc->time.tv_usec >= NSEC_PER_SEC)
+ return -EINVAL;
+ } else {
+ if (txc->time.tv_usec >= USEC_PER_SEC)
+ return -EINVAL;
+ }
+ }
+
+ /*
+ * Check for potential multiplication overflows that can
+ * only happen on 64-bit systems:
+ */
+ if ((txc->modes & ADJ_FREQUENCY) && (BITS_PER_LONG == 64)) {
+ if (LLONG_MIN / PPM_SCALE > txc->freq)
+ return -EINVAL;
+ if (LLONG_MAX / PPM_SCALE < txc->freq)
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+
+/**
* do_adjtimex() - Accessor function to NTP __do_adjtimex function
*/
int do_adjtimex(struct timex *txc)
@@ -2259,12 +2399,12 @@ int do_adjtimex(struct timex *txc)
int ret;
/* Validate the data before disabling interrupts */
- ret = ntp_validate_timex(txc);
+ ret = timekeeping_validate_timex(txc);
if (ret)
return ret;
if (txc->modes & ADJ_SETOFFSET) {
- struct timespec delta;
+ struct timespec64 delta;
delta.tv_sec = txc->time.tv_sec;
delta.tv_nsec = txc->time.tv_usec;
if (!(txc->modes & ADJ_NANO))