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-rw-r--r--arch/x86/include/asm/vgtod.h17
-rw-r--r--arch/x86/kernel/tsc.c10
-rw-r--r--arch/x86/kernel/vsyscall_64.c25
-rw-r--r--arch/x86/vdso/vclock_gettime.c135
4 files changed, 99 insertions, 88 deletions
diff --git a/arch/x86/include/asm/vgtod.h b/arch/x86/include/asm/vgtod.h
index 815285bcaceb..8b38be2de9e1 100644
--- a/arch/x86/include/asm/vgtod.h
+++ b/arch/x86/include/asm/vgtod.h
@@ -5,13 +5,8 @@
#include <linux/clocksource.h>
struct vsyscall_gtod_data {
- seqlock_t lock;
+ seqcount_t seq;
- /* open coded 'struct timespec' */
- time_t wall_time_sec;
- u32 wall_time_nsec;
-
- struct timezone sys_tz;
struct { /* extract of a clocksource struct */
int vclock_mode;
cycle_t cycle_last;
@@ -19,8 +14,16 @@ struct vsyscall_gtod_data {
u32 mult;
u32 shift;
} clock;
- struct timespec wall_to_monotonic;
+
+ /* open coded 'struct timespec' */
+ time_t wall_time_sec;
+ u32 wall_time_nsec;
+ u32 monotonic_time_nsec;
+ time_t monotonic_time_sec;
+
+ struct timezone sys_tz;
struct timespec wall_time_coarse;
+ struct timespec monotonic_time_coarse;
};
extern struct vsyscall_gtod_data vsyscall_gtod_data;
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 899a03f2d181..fc0a147e3727 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -933,6 +933,16 @@ static int __init init_tsc_clocksource(void)
clocksource_tsc.rating = 0;
clocksource_tsc.flags &= ~CLOCK_SOURCE_IS_CONTINUOUS;
}
+
+ /*
+ * Trust the results of the earlier calibration on systems
+ * exporting a reliable TSC.
+ */
+ if (boot_cpu_has(X86_FEATURE_TSC_RELIABLE)) {
+ clocksource_register_khz(&clocksource_tsc, tsc_khz);
+ return 0;
+ }
+
schedule_delayed_work(&tsc_irqwork, 0);
return 0;
}
diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
index b07ba9393564..d5c69860b524 100644
--- a/arch/x86/kernel/vsyscall_64.c
+++ b/arch/x86/kernel/vsyscall_64.c
@@ -52,10 +52,7 @@
#include "vsyscall_trace.h"
DEFINE_VVAR(int, vgetcpu_mode);
-DEFINE_VVAR(struct vsyscall_gtod_data, vsyscall_gtod_data) =
-{
- .lock = __SEQLOCK_UNLOCKED(__vsyscall_gtod_data.lock),
-};
+DEFINE_VVAR(struct vsyscall_gtod_data, vsyscall_gtod_data);
static enum { EMULATE, NATIVE, NONE } vsyscall_mode = EMULATE;
@@ -80,20 +77,15 @@ early_param("vsyscall", vsyscall_setup);
void update_vsyscall_tz(void)
{
- unsigned long flags;
-
- write_seqlock_irqsave(&vsyscall_gtod_data.lock, flags);
- /* sys_tz has changed */
vsyscall_gtod_data.sys_tz = sys_tz;
- write_sequnlock_irqrestore(&vsyscall_gtod_data.lock, flags);
}
void update_vsyscall(struct timespec *wall_time, struct timespec *wtm,
struct clocksource *clock, u32 mult)
{
- unsigned long flags;
+ struct timespec monotonic;
- write_seqlock_irqsave(&vsyscall_gtod_data.lock, flags);
+ write_seqcount_begin(&vsyscall_gtod_data.seq);
/* copy vsyscall data */
vsyscall_gtod_data.clock.vclock_mode = clock->archdata.vclock_mode;
@@ -101,12 +93,19 @@ void update_vsyscall(struct timespec *wall_time, struct timespec *wtm,
vsyscall_gtod_data.clock.mask = clock->mask;
vsyscall_gtod_data.clock.mult = mult;
vsyscall_gtod_data.clock.shift = clock->shift;
+
vsyscall_gtod_data.wall_time_sec = wall_time->tv_sec;
vsyscall_gtod_data.wall_time_nsec = wall_time->tv_nsec;
- vsyscall_gtod_data.wall_to_monotonic = *wtm;
+
+ monotonic = timespec_add(*wall_time, *wtm);
+ vsyscall_gtod_data.monotonic_time_sec = monotonic.tv_sec;
+ vsyscall_gtod_data.monotonic_time_nsec = monotonic.tv_nsec;
+
vsyscall_gtod_data.wall_time_coarse = __current_kernel_time();
+ vsyscall_gtod_data.monotonic_time_coarse =
+ timespec_add(vsyscall_gtod_data.wall_time_coarse, *wtm);
- write_sequnlock_irqrestore(&vsyscall_gtod_data.lock, flags);
+ write_seqcount_end(&vsyscall_gtod_data.seq);
}
static void warn_bad_vsyscall(const char *level, struct pt_regs *regs,
diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
index 6bc0e723b6e8..885eff49d6ab 100644
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -70,100 +70,98 @@ notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
return ret;
}
+notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz)
+{
+ long ret;
+
+ asm("syscall" : "=a" (ret) :
+ "0" (__NR_gettimeofday), "D" (tv), "S" (tz) : "memory");
+ return ret;
+}
+
+
notrace static inline long vgetns(void)
{
long v;
cycles_t cycles;
if (gtod->clock.vclock_mode == VCLOCK_TSC)
cycles = vread_tsc();
- else
+ else if (gtod->clock.vclock_mode == VCLOCK_HPET)
cycles = vread_hpet();
+ else
+ return 0;
v = (cycles - gtod->clock.cycle_last) & gtod->clock.mask;
return (v * gtod->clock.mult) >> gtod->clock.shift;
}
-notrace static noinline int do_realtime(struct timespec *ts)
+/* Code size doesn't matter (vdso is 4k anyway) and this is faster. */
+notrace static int __always_inline do_realtime(struct timespec *ts)
{
unsigned long seq, ns;
+ int mode;
+
do {
- seq = read_seqbegin(&gtod->lock);
+ seq = read_seqcount_begin(&gtod->seq);
+ mode = gtod->clock.vclock_mode;
ts->tv_sec = gtod->wall_time_sec;
ts->tv_nsec = gtod->wall_time_nsec;
ns = vgetns();
- } while (unlikely(read_seqretry(&gtod->lock, seq)));
+ } while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
+
timespec_add_ns(ts, ns);
- return 0;
+ return mode;
}
-notrace static noinline int do_monotonic(struct timespec *ts)
+notrace static int do_monotonic(struct timespec *ts)
{
- unsigned long seq, ns, secs;
+ unsigned long seq, ns;
+ int mode;
+
do {
- seq = read_seqbegin(&gtod->lock);
- secs = gtod->wall_time_sec;
- ns = gtod->wall_time_nsec + vgetns();
- secs += gtod->wall_to_monotonic.tv_sec;
- ns += gtod->wall_to_monotonic.tv_nsec;
- } while (unlikely(read_seqretry(&gtod->lock, seq)));
-
- /* wall_time_nsec, vgetns(), and wall_to_monotonic.tv_nsec
- * are all guaranteed to be nonnegative.
- */
- while (ns >= NSEC_PER_SEC) {
- ns -= NSEC_PER_SEC;
- ++secs;
- }
- ts->tv_sec = secs;
- ts->tv_nsec = ns;
+ seq = read_seqcount_begin(&gtod->seq);
+ mode = gtod->clock.vclock_mode;
+ ts->tv_sec = gtod->monotonic_time_sec;
+ ts->tv_nsec = gtod->monotonic_time_nsec;
+ ns = vgetns();
+ } while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
+ timespec_add_ns(ts, ns);
- return 0;
+ return mode;
}
-notrace static noinline int do_realtime_coarse(struct timespec *ts)
+notrace static int do_realtime_coarse(struct timespec *ts)
{
unsigned long seq;
do {
- seq = read_seqbegin(&gtod->lock);
+ seq = read_seqcount_begin(&gtod->seq);
ts->tv_sec = gtod->wall_time_coarse.tv_sec;
ts->tv_nsec = gtod->wall_time_coarse.tv_nsec;
- } while (unlikely(read_seqretry(&gtod->lock, seq)));
+ } while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
return 0;
}
-notrace static noinline int do_monotonic_coarse(struct timespec *ts)
+notrace static int do_monotonic_coarse(struct timespec *ts)
{
- unsigned long seq, ns, secs;
+ unsigned long seq;
do {
- seq = read_seqbegin(&gtod->lock);
- secs = gtod->wall_time_coarse.tv_sec;
- ns = gtod->wall_time_coarse.tv_nsec;
- secs += gtod->wall_to_monotonic.tv_sec;
- ns += gtod->wall_to_monotonic.tv_nsec;
- } while (unlikely(read_seqretry(&gtod->lock, seq)));
-
- /* wall_time_nsec and wall_to_monotonic.tv_nsec are
- * guaranteed to be between 0 and NSEC_PER_SEC.
- */
- if (ns >= NSEC_PER_SEC) {
- ns -= NSEC_PER_SEC;
- ++secs;
- }
- ts->tv_sec = secs;
- ts->tv_nsec = ns;
+ seq = read_seqcount_begin(&gtod->seq);
+ ts->tv_sec = gtod->monotonic_time_coarse.tv_sec;
+ ts->tv_nsec = gtod->monotonic_time_coarse.tv_nsec;
+ } while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
return 0;
}
notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
{
+ int ret = VCLOCK_NONE;
+
switch (clock) {
case CLOCK_REALTIME:
- if (likely(gtod->clock.vclock_mode != VCLOCK_NONE))
- return do_realtime(ts);
+ ret = do_realtime(ts);
break;
case CLOCK_MONOTONIC:
- if (likely(gtod->clock.vclock_mode != VCLOCK_NONE))
- return do_monotonic(ts);
+ ret = do_monotonic(ts);
break;
case CLOCK_REALTIME_COARSE:
return do_realtime_coarse(ts);
@@ -171,32 +169,33 @@ notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
return do_monotonic_coarse(ts);
}
- return vdso_fallback_gettime(clock, ts);
+ if (ret == VCLOCK_NONE)
+ return vdso_fallback_gettime(clock, ts);
+ return 0;
}
int clock_gettime(clockid_t, struct timespec *)
__attribute__((weak, alias("__vdso_clock_gettime")));
notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
{
- long ret;
- if (likely(gtod->clock.vclock_mode != VCLOCK_NONE)) {
- if (likely(tv != NULL)) {
- BUILD_BUG_ON(offsetof(struct timeval, tv_usec) !=
- offsetof(struct timespec, tv_nsec) ||
- sizeof(*tv) != sizeof(struct timespec));
- do_realtime((struct timespec *)tv);
- tv->tv_usec /= 1000;
- }
- if (unlikely(tz != NULL)) {
- /* Avoid memcpy. Some old compilers fail to inline it */
- tz->tz_minuteswest = gtod->sys_tz.tz_minuteswest;
- tz->tz_dsttime = gtod->sys_tz.tz_dsttime;
- }
- return 0;
+ long ret = VCLOCK_NONE;
+
+ if (likely(tv != NULL)) {
+ BUILD_BUG_ON(offsetof(struct timeval, tv_usec) !=
+ offsetof(struct timespec, tv_nsec) ||
+ sizeof(*tv) != sizeof(struct timespec));
+ ret = do_realtime((struct timespec *)tv);
+ tv->tv_usec /= 1000;
}
- asm("syscall" : "=a" (ret) :
- "0" (__NR_gettimeofday), "D" (tv), "S" (tz) : "memory");
- return ret;
+ if (unlikely(tz != NULL)) {
+ /* Avoid memcpy. Some old compilers fail to inline it */
+ tz->tz_minuteswest = gtod->sys_tz.tz_minuteswest;
+ tz->tz_dsttime = gtod->sys_tz.tz_dsttime;
+ }
+
+ if (ret == VCLOCK_NONE)
+ return vdso_fallback_gtod(tv, tz);
+ return 0;
}
int gettimeofday(struct timeval *, struct timezone *)
__attribute__((weak, alias("__vdso_gettimeofday")));
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-20 01:57:27 +0000