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Subject[PATCH 16/16] time: Rework update_vsyscall to pass timekeeper
Date
Rather then trying to pass fragments of values out to the
vsyscall code, pass the entire timekeeper structure.

This will allow vsyscalls to utilize the fractional shifted
nanoseconds.

CC: Thomas Gleixner <tglx@linutronix.de>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
arch/ia64/kernel/time.c | 28 ++++++++--------
arch/powerpc/kernel/time.c | 25 +++++++------
arch/s390/kernel/time.c | 18 +++++-----
arch/x86/kernel/vsyscall_64.c | 21 ++++++-----
include/linux/clocksource.h | 9 -----
include/linux/timekeeper.h | 75 +++++++++++++++++++++++++++++++++++++++++
kernel/time/timekeeping.c | 59 +-------------------------------
7 files changed, 124 insertions(+), 111 deletions(-)
create mode 100644 include/linux/timekeeper.h
diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
index 43920de..170e381 100644
--- a/arch/ia64/kernel/time.c
+++ b/arch/ia64/kernel/time.c
@@ -20,6 +20,7 @@
#include <linux/efi.h>
#include <linux/timex.h>
#include <linux/clocksource.h>
+#include <linux/timekeeper.h>
#include <linux/platform_device.h>

#include <asm/machvec.h>
@@ -457,27 +458,26 @@ void update_vsyscall_tz(void)
{
}

-void update_vsyscall(struct timespec *wall, struct timespec *wtm,
- struct clocksource *c, u32 mult)
+void update_vsyscall(struct timekeeper *tk)
{
unsigned long flags;

write_seqlock_irqsave(&fsyscall_gtod_data.lock, flags);

- /* copy fsyscall clock data */
- fsyscall_gtod_data.clk_mask = c->mask;
- fsyscall_gtod_data.clk_mult = mult;
- fsyscall_gtod_data.clk_shift = c->shift;
- fsyscall_gtod_data.clk_fsys_mmio = c->archdata.fsys_mmio;
- fsyscall_gtod_data.clk_cycle_last = c->cycle_last;
+ /* copy fsyscall clock data */
+ fsyscall_gtod_data.clk_mask = tk->clock->mask;
+ fsyscall_gtod_data.clk_mult = tk->mult;
+ fsyscall_gtod_data.clk_shift = tk->shift;
+ fsyscall_gtod_data.clk_fsys_mmio = tk->clock->archdata.fsys_mmio;
+ fsyscall_gtod_data.clk_cycle_last = tk->clock->cycle_last;

/* copy kernel time structures */
- fsyscall_gtod_data.wall_time.tv_sec = wall->tv_sec;
- fsyscall_gtod_data.wall_time.tv_nsec = wall->tv_nsec;
- fsyscall_gtod_data.monotonic_time.tv_sec = wtm->tv_sec
- + wall->tv_sec;
- fsyscall_gtod_data.monotonic_time.tv_nsec = wtm->tv_nsec
- + wall->tv_nsec;
+ fsyscall_gtod_data.wall_time.tv_sec = tk->xtime_sec;
+ fsyscall_gtod_data.wall_time.tv_nsec = tk->xtime_nsec >> tk->shift;
+ fsyscall_gtod_data.monotonic_time.tv_sec = tk->xtime_sec
+ + tk->wall_to_monotonic.tv_sec;
+ fsyscall_gtod_data.monotonic_time.tv_nsec =
+ (tk->xtime_nsec >> tk->shift) + tk->wall_to_monotonic.tv_nsec;

/* normalize */
while (fsyscall_gtod_data.monotonic_time.tv_nsec >= NSEC_PER_SEC) {
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 522bb1d..1ffe695 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -54,6 +54,7 @@
#include <linux/irq.h>
#include <linux/delay.h>
#include <linux/irq_work.h>
+#include <linux/timekeeper.h>
#include <asm/trace.h>

#include <asm/io.h>
@@ -811,13 +812,12 @@ static cycle_t timebase_read(struct clocksource *cs)
return (cycle_t)get_tb();
}

-void update_vsyscall(struct timespec *wall_time, struct timespec *wtm,
- struct clocksource *clock, u32 mult)
+void update_vsyscall(struct timekeeper *tk);
{
u64 new_tb_to_xs, new_stamp_xsec;
u32 frac_sec;

- if (clock != &clocksource_timebase)
+ if (tk->clock != &clocksource_timebase)
return;

/* Make userspace gettimeofday spin until we're done. */
@@ -826,14 +826,14 @@ void update_vsyscall(struct timespec *wall_time, struct timespec *wtm,

/* XXX this assumes clock->shift == 22 */
/* 4611686018 ~= 2^(20+64-22) / 1e9 */
- new_tb_to_xs = (u64) mult * 4611686018ULL;
- new_stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC;
+ new_tb_to_xs = (u64) tk->mult * 4611686018ULL;
+ new_stamp_xsec = (u64) (tk->xtime_nsec >> tk->shift) * XSEC_PER_SEC;
do_div(new_stamp_xsec, 1000000000);
- new_stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC;
+ new_stamp_xsec += (u64) tk->xtime_sec * XSEC_PER_SEC;

- BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC);
+ BUG_ON((tk->xtime_nsec >> tk->shift) >= NSEC_PER_SEC);
/* this is tv_nsec / 1e9 as a 0.32 fraction */
- frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32;
+ frac_sec = ((u64) (tk->xtime_nsec >> tk->shift) * 18446744073ULL) >> 32;

/*
* tb_update_count is used to allow the userspace gettimeofday code
@@ -846,12 +846,13 @@ void update_vsyscall(struct timespec *wall_time, struct timespec *wtm,
* We expect the caller to have done the first increment of
* vdso_data->tb_update_count already.
*/
- vdso_data->tb_orig_stamp = clock->cycle_last;
+ vdso_data->tb_orig_stamp = tk->clock->cycle_last;
vdso_data->stamp_xsec = new_stamp_xsec;
vdso_data->tb_to_xs = new_tb_to_xs;
- vdso_data->wtom_clock_sec = wtm->tv_sec;
- vdso_data->wtom_clock_nsec = wtm->tv_nsec;
- vdso_data->stamp_xtime = *wall_time;
+ vdso_data->wtom_clock_sec = tk->wall_to_monotonic.tv_sec;
+ vdso_data->wtom_clock_nsec = tk->wall_to_monotonic.tv_nsec;
+ vdso_data->stamp_xtime.tv_sec = tk->xtime_sec;
+ vdso_data->stamp_xtime.tv_nsec = (tk->xtime_nsec >> tk->shift);
vdso_data->stamp_sec_fraction = frac_sec;
smp_wmb();
++(vdso_data->tb_update_count);
diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c
index ebbfab3..f624449 100644
--- a/arch/s390/kernel/time.c
+++ b/arch/s390/kernel/time.c
@@ -36,6 +36,7 @@
#include <linux/timex.h>
#include <linux/notifier.h>
#include <linux/clocksource.h>
+#include <linux/timekeeper.h>
#include <linux/clockchips.h>
#include <linux/gfp.h>
#include <linux/kprobes.h>
@@ -217,21 +218,20 @@ struct clocksource * __init clocksource_default_clock(void)
return &clocksource_tod;
}

-void update_vsyscall(struct timespec *wall_time, struct timespec *wtm,
- struct clocksource *clock, u32 mult)
+void update_vsyscall(struct timekeeper *tk);
{
- if (clock != &clocksource_tod)
+ if (tk->clock != &clocksource_tod)
return;

/* Make userspace gettimeofday spin until we're done. */
++vdso_data->tb_update_count;
smp_wmb();
- vdso_data->xtime_tod_stamp = clock->cycle_last;
- vdso_data->xtime_clock_sec = wall_time->tv_sec;
- vdso_data->xtime_clock_nsec = wall_time->tv_nsec;
- vdso_data->wtom_clock_sec = wtm->tv_sec;
- vdso_data->wtom_clock_nsec = wtm->tv_nsec;
- vdso_data->ntp_mult = mult;
+ vdso_data->xtime_tod_stamp = tk->clock->cycle_last;
+ vdso_data->xtime_clock_sec = tk->xtime_sec;
+ vdso_data->xtime_clock_nsec = (tk->xtime_nsec >> tk->shift);
+ vdso_data->wtom_clock_sec = tk->wall_to_monotonic.tv_sec;
+ vdso_data->wtom_clock_nsec = tk->wall_to_monotonic.tv_nsec;
+ vdso_data->ntp_mult = tk->mult;
smp_wmb();
++vdso_data->tb_update_count;
}
diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
index e4d4a22..f78c6fd 100644
--- a/arch/x86/kernel/vsyscall_64.c
+++ b/arch/x86/kernel/vsyscall_64.c
@@ -27,6 +27,7 @@
#include <linux/sysctl.h>
#include <linux/topology.h>
#include <linux/clocksource.h>
+#include <linux/timekeeper.h>
#include <linux/getcpu.h>
#include <linux/cpu.h>
#include <linux/smp.h>
@@ -88,22 +89,22 @@ void update_vsyscall_tz(void)
write_sequnlock_irqrestore(&vsyscall_gtod_data.lock, flags);
}

-void update_vsyscall(struct timespec *wall_time, struct timespec *wtm,
- struct clocksource *clock, u32 mult)
+void update_vsyscall(struct timekeeper *tk)
{
unsigned long flags;

write_seqlock_irqsave(&vsyscall_gtod_data.lock, flags);

/* copy vsyscall data */
- vsyscall_gtod_data.clock.vclock_mode = clock->archdata.vclock_mode;
- vsyscall_gtod_data.clock.cycle_last = clock->cycle_last;
- 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;
+ vsyscall_gtod_data.clock.vclock_mode =
+ tk->clock->archdata.vclock_mode;
+ vsyscall_gtod_data.clock.cycle_last = tk->clock->cycle_last;
+ vsyscall_gtod_data.clock.mask = tk->clock->mask;
+ vsyscall_gtod_data.clock.mult = tk->mult;
+ vsyscall_gtod_data.clock.shift = tk->clock->shift;
+ vsyscall_gtod_data.wall_time_sec = tk->xtime_sec;
+ vsyscall_gtod_data.wall_time_nsec = tk->xtime_nsec >> tk->shift;
+ vsyscall_gtod_data.wall_to_monotonic = tk->wall_to_monotonic;
vsyscall_gtod_data.wall_time_coarse = __current_kernel_time();

write_sequnlock_irqrestore(&vsyscall_gtod_data.lock, flags);
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index 139c4db..d21d5f0 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -321,17 +321,8 @@ clocksource_calc_mult_shift(struct clocksource *cs, u32 freq, u32 minsec)
}

#ifdef CONFIG_GENERIC_TIME_VSYSCALL
-extern void
-update_vsyscall(struct timespec *ts, struct timespec *wtm,
- struct clocksource *c, u32 mult);
extern void update_vsyscall_tz(void);
#else
-static inline void
-update_vsyscall(struct timespec *ts, struct timespec *wtm,
- struct clocksource *c, u32 mult)
-{
-}
-
static inline void update_vsyscall_tz(void)
{
}
diff --git a/include/linux/timekeeper.h b/include/linux/timekeeper.h
new file mode 100644
index 0000000..89d1b0c
--- /dev/null
+++ b/include/linux/timekeeper.h
@@ -0,0 +1,75 @@
+#ifndef _LINUX_TIMEKEEPER_H
+#define _LINUX_TIMEKEEPER_H
+
+#include <linux/clocksource.h>
+
+/*
+ * You should not include this unless you are arch
+ * specific vsyscall code!
+ */
+
+/* Structure holding internal timekeeping values. */
+struct timekeeper {
+ /* Current clocksource used for timekeeping. */
+ struct clocksource *clock;
+ /* NTP adjusted clock multiplier */
+ u32 mult;
+ /* The shift value of the current clocksource. */
+ int shift;
+
+ /* Number of clock cycles in one NTP interval. */
+ cycle_t cycle_interval;
+ /* Number of clock shifted nano seconds in one NTP interval. */
+ u64 xtime_interval;
+ /* shifted nano seconds left over when rounding cycle_interval */
+ s64 xtime_remainder;
+ /* Raw nano seconds accumulated per NTP interval. */
+ u32 raw_interval;
+
+ /* Current CLOCK_REALTIME time in seconds */
+ u64 xtime_sec;
+ /* Clock shifted nano seconds */
+ u64 xtime_nsec;
+
+ /* Difference between accumulated time and NTP time in ntp
+ * shifted nano seconds. */
+ s64 ntp_error;
+ /* Shift conversion between clock shifted nano seconds and
+ * ntp shifted nano seconds. */
+ int ntp_error_shift;
+
+ /*
+ * wall_to_monotonic is what we need to add to xtime (or xtime corrected
+ * for sub jiffie times) to get to monotonic time. Monotonic is pegged
+ * at zero at system boot time, so wall_to_monotonic will be negative,
+ * however, we will ALWAYS keep the tv_nsec part positive so we can use
+ * the usual normalization.
+ *
+ * wall_to_monotonic is moved after resume from suspend for the
+ * monotonic time not to jump. We need to add total_sleep_time to
+ * wall_to_monotonic to get the real boot based time offset.
+ *
+ * - wall_to_monotonic is no longer the boot time, getboottime must be
+ * used instead.
+ */
+ struct timespec wall_to_monotonic;
+ /* time spent in suspend */
+ struct timespec total_sleep_time;
+ /* The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock. */
+ struct timespec raw_time;
+
+ /* Seqlock for all timekeeper values */
+ seqlock_t lock;
+};
+
+#ifdef CONFIG_GENERIC_TIME_VSYSCALL
+extern void
+update_vsyscall(struct timekeeper *tk);
+#else
+static inline void
+update_vsyscall(struct timekeeper *tk)
+{
+}
+#endif
+
+#endif /* _LINUX_TIMEKEEPER_H */
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index ba595a3..0f28d36 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -20,60 +20,7 @@
#include <linux/time.h>
#include <linux/tick.h>
#include <linux/stop_machine.h>
-
-/* Structure holding internal timekeeping values. */
-struct timekeeper {
- /* Current clocksource used for timekeeping. */
- struct clocksource *clock;
- /* NTP adjusted clock multiplier */
- u32 mult;
- /* The shift value of the current clocksource. */
- int shift;
-
- /* Number of clock cycles in one NTP interval. */
- cycle_t cycle_interval;
- /* Number of clock shifted nano seconds in one NTP interval. */
- u64 xtime_interval;
- /* shifted nano seconds left over when rounding cycle_interval */
- s64 xtime_remainder;
- /* Raw nano seconds accumulated per NTP interval. */
- u32 raw_interval;
-
- /* Current CLOCK_REALTIME time in seconds */
- u64 xtime_sec;
- /* Clock shifted nano seconds */
- u64 xtime_nsec;
-
- /* Difference between accumulated time and NTP time in ntp
- * shifted nano seconds. */
- s64 ntp_error;
- /* Shift conversion between clock shifted nano seconds and
- * ntp shifted nano seconds. */
- int ntp_error_shift;
-
- /*
- * wall_to_monotonic is what we need to add to xtime (or xtime corrected
- * for sub jiffie times) to get to monotonic time. Monotonic is pegged
- * at zero at system boot time, so wall_to_monotonic will be negative,
- * however, we will ALWAYS keep the tv_nsec part positive so we can use
- * the usual normalization.
- *
- * wall_to_monotonic is moved after resume from suspend for the
- * monotonic time not to jump. We need to add total_sleep_time to
- * wall_to_monotonic to get the real boot based time offset.
- *
- * - wall_to_monotonic is no longer the boot time, getboottime must be
- * used instead.
- */
- struct timespec wall_to_monotonic;
- /* time spent in suspend */
- struct timespec total_sleep_time;
- /* The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock. */
- struct timespec raw_time;
-
- /* Seqlock for all timekeeper values */
- seqlock_t lock;
-};
+#include <linux/timekeeper.h>

static struct timekeeper timekeeper;

@@ -208,13 +155,11 @@ static inline s64 timekeeping_get_ns_raw(void)
/* must hold write on timekeeper.lock */
static void timekeeping_update(struct timekeeper *tk, bool clearntp)
{
- struct timespec xt;
if (clearntp) {
tk->ntp_error = 0;
ntp_clear();
}
- xt = timekeeper_xtime(tk);
- update_vsyscall(&xt, &tk->wall_to_monotonic, tk->clock, tk->mult);
+ update_vsyscall(tk);
}


--
1.7.3.2.146.gca209


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