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-rw-r--r--arch/x86/Kconfig2
-rw-r--r--arch/x86/kernel/tsc.c21
-rw-r--r--arch/x86/kernel/vsyscall_gtod.c23
-rw-r--r--arch/x86/kvm/x86.c62
4 files changed, 43 insertions, 65 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 6b71f0417293..6cfeb082a422 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -108,9 +108,9 @@ config X86
select CLOCKSOURCE_WATCHDOG
select GENERIC_CLOCKEVENTS
select ARCH_CLOCKSOURCE_DATA
+ select CLOCKSOURCE_VALIDATE_LAST_CYCLE
select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
select GENERIC_TIME_VSYSCALL
- select KTIME_SCALAR if X86_32
select GENERIC_STRNCPY_FROM_USER
select GENERIC_STRNLEN_USER
select HAVE_CONTEXT_TRACKING if X86_64
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 56b0c338061e..b6025f9e36c6 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -950,7 +950,7 @@ core_initcall(cpufreq_tsc);
static struct clocksource clocksource_tsc;
/*
- * We compare the TSC to the cycle_last value in the clocksource
+ * We used to compare the TSC to the cycle_last value in the clocksource
* structure to avoid a nasty time-warp. This can be observed in a
* very small window right after one CPU updated cycle_last under
* xtime/vsyscall_gtod lock and the other CPU reads a TSC value which
@@ -960,26 +960,23 @@ static struct clocksource clocksource_tsc;
* due to the unsigned delta calculation of the time keeping core
* code, which is necessary to support wrapping clocksources like pm
* timer.
+ *
+ * This sanity check is now done in the core timekeeping code.
+ * checking the result of read_tsc() - cycle_last for being negative.
+ * That works because CLOCKSOURCE_MASK(64) does not mask out any bit.
*/
static cycle_t read_tsc(struct clocksource *cs)
{
- cycle_t ret = (cycle_t)get_cycles();
-
- return ret >= clocksource_tsc.cycle_last ?
- ret : clocksource_tsc.cycle_last;
-}
-
-static void resume_tsc(struct clocksource *cs)
-{
- if (!boot_cpu_has(X86_FEATURE_NONSTOP_TSC_S3))
- clocksource_tsc.cycle_last = 0;
+ return (cycle_t)get_cycles();
}
+/*
+ * .mask MUST be CLOCKSOURCE_MASK(64). See comment above read_tsc()
+ */
static struct clocksource clocksource_tsc = {
.name = "tsc",
.rating = 300,
.read = read_tsc,
- .resume = resume_tsc,
.mask = CLOCKSOURCE_MASK(64),
.flags = CLOCK_SOURCE_IS_CONTINUOUS |
CLOCK_SOURCE_MUST_VERIFY,
diff --git a/arch/x86/kernel/vsyscall_gtod.c b/arch/x86/kernel/vsyscall_gtod.c
index 9531fbb123ba..c7d791f32b98 100644
--- a/arch/x86/kernel/vsyscall_gtod.c
+++ b/arch/x86/kernel/vsyscall_gtod.c
@@ -31,29 +31,30 @@ void update_vsyscall(struct timekeeper *tk)
gtod_write_begin(vdata);
/* copy vsyscall data */
- vdata->vclock_mode = tk->clock->archdata.vclock_mode;
- vdata->cycle_last = tk->clock->cycle_last;
- vdata->mask = tk->clock->mask;
- vdata->mult = tk->mult;
- vdata->shift = tk->shift;
+ vdata->vclock_mode = tk->tkr.clock->archdata.vclock_mode;
+ vdata->cycle_last = tk->tkr.cycle_last;
+ vdata->mask = tk->tkr.mask;
+ vdata->mult = tk->tkr.mult;
+ vdata->shift = tk->tkr.shift;
vdata->wall_time_sec = tk->xtime_sec;
- vdata->wall_time_snsec = tk->xtime_nsec;
+ vdata->wall_time_snsec = tk->tkr.xtime_nsec;
vdata->monotonic_time_sec = tk->xtime_sec
+ tk->wall_to_monotonic.tv_sec;
- vdata->monotonic_time_snsec = tk->xtime_nsec
+ vdata->monotonic_time_snsec = tk->tkr.xtime_nsec
+ ((u64)tk->wall_to_monotonic.tv_nsec
- << tk->shift);
+ << tk->tkr.shift);
while (vdata->monotonic_time_snsec >=
- (((u64)NSEC_PER_SEC) << tk->shift)) {
+ (((u64)NSEC_PER_SEC) << tk->tkr.shift)) {
vdata->monotonic_time_snsec -=
- ((u64)NSEC_PER_SEC) << tk->shift;
+ ((u64)NSEC_PER_SEC) << tk->tkr.shift;
vdata->monotonic_time_sec++;
}
vdata->wall_time_coarse_sec = tk->xtime_sec;
- vdata->wall_time_coarse_nsec = (long)(tk->xtime_nsec >> tk->shift);
+ vdata->wall_time_coarse_nsec = (long)(tk->tkr.xtime_nsec >>
+ tk->tkr.shift);
vdata->monotonic_time_coarse_sec =
vdata->wall_time_coarse_sec + tk->wall_to_monotonic.tv_sec;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b86d329b953a..ca3d760dd581 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1020,9 +1020,8 @@ struct pvclock_gtod_data {
u32 shift;
} clock;
- /* open coded 'struct timespec' */
- u64 monotonic_time_snsec;
- time_t monotonic_time_sec;
+ u64 boot_ns;
+ u64 nsec_base;
};
static struct pvclock_gtod_data pvclock_gtod_data;
@@ -1030,27 +1029,21 @@ static struct pvclock_gtod_data pvclock_gtod_data;
static void update_pvclock_gtod(struct timekeeper *tk)
{
struct pvclock_gtod_data *vdata = &pvclock_gtod_data;
+ u64 boot_ns;
+
+ boot_ns = ktime_to_ns(ktime_add(tk->tkr.base_mono, tk->offs_boot));
write_seqcount_begin(&vdata->seq);
/* copy pvclock gtod data */
- vdata->clock.vclock_mode = tk->clock->archdata.vclock_mode;
- vdata->clock.cycle_last = tk->clock->cycle_last;
- vdata->clock.mask = tk->clock->mask;
- vdata->clock.mult = tk->mult;
- vdata->clock.shift = tk->shift;
-
- vdata->monotonic_time_sec = tk->xtime_sec
- + tk->wall_to_monotonic.tv_sec;
- vdata->monotonic_time_snsec = tk->xtime_nsec
- + (tk->wall_to_monotonic.tv_nsec
- << tk->shift);
- while (vdata->monotonic_time_snsec >=
- (((u64)NSEC_PER_SEC) << tk->shift)) {
- vdata->monotonic_time_snsec -=
- ((u64)NSEC_PER_SEC) << tk->shift;
- vdata->monotonic_time_sec++;
- }
+ vdata->clock.vclock_mode = tk->tkr.clock->archdata.vclock_mode;
+ vdata->clock.cycle_last = tk->tkr.cycle_last;
+ vdata->clock.mask = tk->tkr.mask;
+ vdata->clock.mult = tk->tkr.mult;
+ vdata->clock.shift = tk->tkr.shift;
+
+ vdata->boot_ns = boot_ns;
+ vdata->nsec_base = tk->tkr.xtime_nsec;
write_seqcount_end(&vdata->seq);
}
@@ -1145,11 +1138,7 @@ static void kvm_get_time_scale(uint32_t scaled_khz, uint32_t base_khz,
static inline u64 get_kernel_ns(void)
{
- struct timespec ts;
-
- ktime_get_ts(&ts);
- monotonic_to_bootbased(&ts);
- return timespec_to_ns(&ts);
+ return ktime_get_boot_ns();
}
#ifdef CONFIG_X86_64
@@ -1414,23 +1403,22 @@ static inline u64 vgettsc(cycle_t *cycle_now)
return v * gtod->clock.mult;
}
-static int do_monotonic(struct timespec *ts, cycle_t *cycle_now)
+static int do_monotonic_boot(s64 *t, cycle_t *cycle_now)
{
+ struct pvclock_gtod_data *gtod = &pvclock_gtod_data;
unsigned long seq;
- u64 ns;
int mode;
- struct pvclock_gtod_data *gtod = &pvclock_gtod_data;
+ u64 ns;
- ts->tv_nsec = 0;
do {
seq = read_seqcount_begin(&gtod->seq);
mode = gtod->clock.vclock_mode;
- ts->tv_sec = gtod->monotonic_time_sec;
- ns = gtod->monotonic_time_snsec;
+ ns = gtod->nsec_base;
ns += vgettsc(cycle_now);
ns >>= gtod->clock.shift;
+ ns += gtod->boot_ns;
} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
- timespec_add_ns(ts, ns);
+ *t = ns;
return mode;
}
@@ -1438,19 +1426,11 @@ static int do_monotonic(struct timespec *ts, cycle_t *cycle_now)
/* returns true if host is using tsc clocksource */
static bool kvm_get_time_and_clockread(s64 *kernel_ns, cycle_t *cycle_now)
{
- struct timespec ts;
-
/* checked again under seqlock below */
if (pvclock_gtod_data.clock.vclock_mode != VCLOCK_TSC)
return false;
- if (do_monotonic(&ts, cycle_now) != VCLOCK_TSC)
- return false;
-
- monotonic_to_bootbased(&ts);
- *kernel_ns = timespec_to_ns(&ts);
-
- return true;
+ return do_monotonic_boot(kernel_ns, cycle_now) == VCLOCK_TSC;
}
#endif
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-02 04:34:02 +0300