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Commit 650ea024 authored by John Stultz's avatar John Stultz
Browse files

time: Convert x86_64 to using new update_vsyscall 



Switch x86_64 to using sub-ns precise vsyscall

Cc: Tony Luck <tony.luck@intel.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
parent 92bb1fcf

arch/x86/Kconfig

+1 −1
Original line number Original line Diff line number Diff line
@@ -93,7 +93,7 @@ config X86 
	select GENERIC_CLOCKEVENTS

	select GENERIC_CLOCKEVENTS

	select ARCH_CLOCKSOURCE_DATA if X86_64

	select ARCH_CLOCKSOURCE_DATA if X86_64

	select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)

	select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)

	select GENERIC_TIME_VSYSCALL_OLD if X86_64

	select GENERIC_TIME_VSYSCALL if X86_64

	select KTIME_SCALAR if X86_32

	select KTIME_SCALAR if X86_32

	select GENERIC_STRNCPY_FROM_USER

	select GENERIC_STRNCPY_FROM_USER

	select GENERIC_STRNLEN_USER

	select GENERIC_STRNLEN_USER

arch/x86/include/asm/vgtod.h

+2 −2
Original line number Original line Diff line number Diff line
@@ -17,8 +17,8 @@ struct vsyscall_gtod_data { 




	/* open coded 'struct timespec' */

	/* open coded 'struct timespec' */

	time_t		wall_time_sec;

	time_t		wall_time_sec;

	u32		wall_time_nsec;

	u64		wall_time_snsec;

	u32		monotonic_time_nsec;

	u64		monotonic_time_snsec;

	time_t		monotonic_time_sec;

	time_t		monotonic_time_sec;





	struct timezone sys_tz;

	struct timezone sys_tz;

arch/x86/kernel/vsyscall_64.c

+28 −19
Original line number Original line Diff line number Diff line
@@ -82,32 +82,41 @@ void update_vsyscall_tz(void) 
	vsyscall_gtod_data.sys_tz = sys_tz;

	vsyscall_gtod_data.sys_tz = sys_tz;

}

}





void update_vsyscall_old(struct timespec *wall_time, struct timespec *wtm,

void update_vsyscall(struct timekeeper *tk)

			struct clocksource *clock, u32 mult)

{

{

	struct timespec monotonic;

	struct vsyscall_gtod_data *vdata = &vsyscall_gtod_data;





	write_seqcount_begin(&vsyscall_gtod_data.seq);

	write_seqcount_begin(&vdata->seq);





	/* copy vsyscall data */

	/* copy vsyscall data */

	vsyscall_gtod_data.clock.vclock_mode	= clock->archdata.vclock_mode;

	vdata->clock.vclock_mode	= tk->clock->archdata.vclock_mode;

	vsyscall_gtod_data.clock.cycle_last	= clock->cycle_last;

	vdata->clock.cycle_last		= tk->clock->cycle_last;

	vsyscall_gtod_data.clock.mask		= clock->mask;

	vdata->clock.mask		= tk->clock->mask;

	vsyscall_gtod_data.clock.mult		= mult;

	vdata->clock.mult		= tk->mult;

	vsyscall_gtod_data.clock.shift		= clock->shift;

	vdata->clock.shift		= tk->shift;





	vsyscall_gtod_data.wall_time_sec	= wall_time->tv_sec;

	vdata->wall_time_sec		= tk->xtime_sec;

	vsyscall_gtod_data.wall_time_nsec	= wall_time->tv_nsec;

	vdata->wall_time_snsec		= tk->xtime_nsec;



	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++;

	}





	monotonic = timespec_add(*wall_time, *wtm);

	vdata->wall_time_coarse.tv_sec	= tk->xtime_sec;

	vsyscall_gtod_data.monotonic_time_sec	= monotonic.tv_sec;

	vdata->wall_time_coarse.tv_nsec	= (long)(tk->xtime_nsec >> tk->shift);

	vsyscall_gtod_data.monotonic_time_nsec	= monotonic.tv_nsec;





	vsyscall_gtod_data.wall_time_coarse	= __current_kernel_time();

	vdata->monotonic_time_coarse	= timespec_add(vdata->wall_time_coarse,

	vsyscall_gtod_data.monotonic_time_coarse =

							tk->wall_to_monotonic);

		timespec_add(vsyscall_gtod_data.wall_time_coarse, *wtm);





	write_seqcount_end(&vsyscall_gtod_data.seq);

	write_seqcount_end(&vdata->seq);

}

}





static void warn_bad_vsyscall(const char *level, struct pt_regs *regs,

static void warn_bad_vsyscall(const char *level, struct pt_regs *regs,

arch/x86/vdso/vclock_gettime.c

+14 −8
Original line number Original line Diff line number Diff line
@@ -80,7 +80,7 @@ notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz) 
}

}









notrace static inline long vgetns(void)

notrace static inline u64 vgetsns(void)

{

{

	long v;

	long v;

	cycles_t cycles;

	cycles_t cycles;
@@ -91,21 +91,24 @@ notrace static inline long vgetns(void) 
	else

	else

		return 0;

		return 0;

	v = (cycles - gtod->clock.cycle_last) & gtod->clock.mask;

	v = (cycles - gtod->clock.cycle_last) & gtod->clock.mask;

	return (v * gtod->clock.mult) >> gtod->clock.shift;

	return v * gtod->clock.mult;

}

}





/* Code size doesn't matter (vdso is 4k anyway) and this is faster. */

/* Code size doesn't matter (vdso is 4k anyway) and this is faster. */

notrace static int __always_inline do_realtime(struct timespec *ts)

notrace static int __always_inline do_realtime(struct timespec *ts)

{

{

	unsigned long seq, ns;

	unsigned long seq;

	u64 ns;

	int mode;

	int mode;





	ts->tv_nsec = 0;

	do {

	do {

		seq = read_seqcount_begin(&gtod->seq);

		seq = read_seqcount_begin(&gtod->seq);

		mode = gtod->clock.vclock_mode;

		mode = gtod->clock.vclock_mode;

		ts->tv_sec = gtod->wall_time_sec;

		ts->tv_sec = gtod->wall_time_sec;

		ts->tv_nsec = gtod->wall_time_nsec;

		ns = gtod->wall_time_snsec;

		ns = vgetns();

		ns += vgetsns();

		ns >>= gtod->clock.shift;

	} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));

	} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));





	timespec_add_ns(ts, ns);

	timespec_add_ns(ts, ns);
@@ -114,15 +117,18 @@ notrace static int __always_inline do_realtime(struct timespec *ts) 




notrace static int do_monotonic(struct timespec *ts)

notrace static int do_monotonic(struct timespec *ts)

{

{

	unsigned long seq, ns;

	unsigned long seq;

	u64 ns;

	int mode;

	int mode;





	ts->tv_nsec = 0;

	do {

	do {

		seq = read_seqcount_begin(&gtod->seq);

		seq = read_seqcount_begin(&gtod->seq);

		mode = gtod->clock.vclock_mode;

		mode = gtod->clock.vclock_mode;

		ts->tv_sec = gtod->monotonic_time_sec;

		ts->tv_sec = gtod->monotonic_time_sec;

		ts->tv_nsec = gtod->monotonic_time_nsec;

		ns = gtod->monotonic_time_snsec;

		ns = vgetns();

		ns += vgetsns();

		ns >>= gtod->clock.shift;

	} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));

	} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));

	timespec_add_ns(ts, ns);

	timespec_add_ns(ts, ns);