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-rw-r--r--sys/kern/kern_tc.c110
1 files changed, 69 insertions, 41 deletions
diff --git a/sys/kern/kern_tc.c b/sys/kern/kern_tc.c
index 9dca0e8..01c61bd 100644
--- a/sys/kern/kern_tc.c
+++ b/sys/kern/kern_tc.c
@@ -34,6 +34,7 @@ __FBSDID("$FreeBSD$");
#include <sys/timetc.h>
#include <sys/timex.h>
#include <sys/vdso.h>
+#include <machine/atomic.h>
/*
* A large step happens on boot. This constant detects such steps.
@@ -71,7 +72,7 @@ struct timehands {
struct timeval th_microtime;
struct timespec th_nanotime;
/* Fields not to be copied in tc_windup start with th_generation. */
- volatile u_int th_generation;
+ u_int th_generation;
struct timehands *th_next;
};
@@ -189,6 +190,33 @@ tc_delta(struct timehands *th)
tc->tc_counter_mask);
}
+static u_int
+tc_getgen(struct timehands *th)
+{
+
+#ifdef SMP
+ return (atomic_load_acq_int(&th->th_generation));
+#else
+ u_int gen;
+
+ gen = th->th_generation;
+ __compiler_membar();
+ return (gen);
+#endif
+}
+
+static void
+tc_setgen(struct timehands *th, u_int newgen)
+{
+
+#ifdef SMP
+ atomic_store_rel_int(&th->th_generation, newgen);
+#else
+ __compiler_membar();
+ th->th_generation = newgen;
+#endif
+}
+
/*
* Functions for reading the time. We have to loop until we are sure that
* the timehands that we operated on was not updated under our feet. See
@@ -204,10 +232,10 @@ fbclock_binuptime(struct bintime *bt)
do {
th = timehands;
- gen = th->th_generation;
+ gen = tc_getgen(th);
*bt = th->th_offset;
bintime_addx(bt, th->th_scale * tc_delta(th));
- } while (gen == 0 || gen != th->th_generation);
+ } while (gen == 0 || gen != tc_getgen(th));
}
void
@@ -262,9 +290,9 @@ fbclock_getbinuptime(struct bintime *bt)
do {
th = timehands;
- gen = th->th_generation;
+ gen = tc_getgen(th);
*bt = th->th_offset;
- } while (gen == 0 || gen != th->th_generation);
+ } while (gen == 0 || gen != tc_getgen(th));
}
void
@@ -275,9 +303,9 @@ fbclock_getnanouptime(struct timespec *tsp)
do {
th = timehands;
- gen = th->th_generation;
+ gen = tc_getgen(th);
bintime2timespec(&th->th_offset, tsp);
- } while (gen == 0 || gen != th->th_generation);
+ } while (gen == 0 || gen != tc_getgen(th));
}
void
@@ -288,9 +316,9 @@ fbclock_getmicrouptime(struct timeval *tvp)
do {
th = timehands;
- gen = th->th_generation;
+ gen = tc_getgen(th);
bintime2timeval(&th->th_offset, tvp);
- } while (gen == 0 || gen != th->th_generation);
+ } while (gen == 0 || gen != tc_getgen(th));
}
void
@@ -301,9 +329,9 @@ fbclock_getbintime(struct bintime *bt)
do {
th = timehands;
- gen = th->th_generation;
+ gen = tc_getgen(th);
*bt = th->th_offset;
- } while (gen == 0 || gen != th->th_generation);
+ } while (gen == 0 || gen != tc_getgen(th));
bintime_add(bt, &boottimebin);
}
@@ -315,9 +343,9 @@ fbclock_getnanotime(struct timespec *tsp)
do {
th = timehands;
- gen = th->th_generation;
+ gen = tc_getgen(th);
*tsp = th->th_nanotime;
- } while (gen == 0 || gen != th->th_generation);
+ } while (gen == 0 || gen != tc_getgen(th));
}
void
@@ -328,9 +356,9 @@ fbclock_getmicrotime(struct timeval *tvp)
do {
th = timehands;
- gen = th->th_generation;
+ gen = tc_getgen(th);
*tvp = th->th_microtime;
- } while (gen == 0 || gen != th->th_generation);
+ } while (gen == 0 || gen != tc_getgen(th));
}
#else /* !FFCLOCK */
void
@@ -341,10 +369,10 @@ binuptime(struct bintime *bt)
do {
th = timehands;
- gen = th->th_generation;
+ gen = tc_getgen(th);
*bt = th->th_offset;
bintime_addx(bt, th->th_scale * tc_delta(th));
- } while (gen == 0 || gen != th->th_generation);
+ } while (gen == 0 || gen != tc_getgen(th));
}
void
@@ -399,9 +427,9 @@ getbinuptime(struct bintime *bt)
do {
th = timehands;
- gen = th->th_generation;
+ gen = tc_getgen(th);
*bt = th->th_offset;
- } while (gen == 0 || gen != th->th_generation);
+ } while (gen == 0 || gen != tc_getgen(th));
}
void
@@ -412,9 +440,9 @@ getnanouptime(struct timespec *tsp)
do {
th = timehands;
- gen = th->th_generation;
+ gen = tc_getgen(th);
bintime2timespec(&th->th_offset, tsp);
- } while (gen == 0 || gen != th->th_generation);
+ } while (gen == 0 || gen != tc_getgen(th));
}
void
@@ -425,9 +453,9 @@ getmicrouptime(struct timeval *tvp)
do {
th = timehands;
- gen = th->th_generation;
+ gen = tc_getgen(th);
bintime2timeval(&th->th_offset, tvp);
- } while (gen == 0 || gen != th->th_generation);
+ } while (gen == 0 || gen != tc_getgen(th));
}
void
@@ -438,9 +466,9 @@ getbintime(struct bintime *bt)
do {
th = timehands;
- gen = th->th_generation;
+ gen = tc_getgen(th);
*bt = th->th_offset;
- } while (gen == 0 || gen != th->th_generation);
+ } while (gen == 0 || gen != tc_getgen(th));
bintime_add(bt, &boottimebin);
}
@@ -452,9 +480,9 @@ getnanotime(struct timespec *tsp)
do {
th = timehands;
- gen = th->th_generation;
+ gen = tc_getgen(th);
*tsp = th->th_nanotime;
- } while (gen == 0 || gen != th->th_generation);
+ } while (gen == 0 || gen != tc_getgen(th));
}
void
@@ -465,9 +493,9 @@ getmicrotime(struct timeval *tvp)
do {
th = timehands;
- gen = th->th_generation;
+ gen = tc_getgen(th);
*tvp = th->th_microtime;
- } while (gen == 0 || gen != th->th_generation);
+ } while (gen == 0 || gen != tc_getgen(th));
}
#endif /* FFCLOCK */
@@ -880,11 +908,11 @@ ffclock_read_counter(ffcounter *ffcount)
*/
do {
th = timehands;
- gen = th->th_generation;
+ gen = tc_getgen(th);
ffth = fftimehands;
delta = tc_delta(th);
*ffcount = ffth->tick_ffcount;
- } while (gen == 0 || gen != th->th_generation);
+ } while (gen == 0 || gen != tc_getgen(th));
*ffcount += delta;
}
@@ -988,9 +1016,9 @@ dtrace_getnanotime(struct timespec *tsp)
do {
th = timehands;
- gen = th->th_generation;
+ gen = tc_getgen(th);
*tsp = th->th_nanotime;
- } while (gen == 0 || gen != th->th_generation);
+ } while (gen == 0 || gen != tc_getgen(th));
}
/*
@@ -1028,7 +1056,7 @@ sysclock_getsnapshot(struct sysclock_snap *clock_snap, int fast)
do {
th = timehands;
- gen = th->th_generation;
+ gen = tc_getgen(th);
fbi->th_scale = th->th_scale;
fbi->tick_time = th->th_offset;
#ifdef FFCLOCK
@@ -1042,7 +1070,7 @@ sysclock_getsnapshot(struct sysclock_snap *clock_snap, int fast)
#endif
if (!fast)
delta = tc_delta(th);
- } while (gen == 0 || gen != th->th_generation);
+ } while (gen == 0 || gen != tc_getgen(th));
clock_snap->delta = delta;
clock_snap->sysclock_active = sysclock_active;
@@ -1260,7 +1288,7 @@ tc_windup(void)
tho = timehands;
th = tho->th_next;
ogen = th->th_generation;
- th->th_generation = 0;
+ tc_setgen(th, 0);
bcopy(tho, th, offsetof(struct timehands, th_generation));
/*
@@ -1377,7 +1405,7 @@ tc_windup(void)
*/
if (++ogen == 0)
ogen = 1;
- th->th_generation = ogen;
+ tc_setgen(th, ogen);
/* Go live with the new struct timehands. */
#ifdef FFCLOCK
@@ -1651,13 +1679,13 @@ pps_capture(struct pps_state *pps)
KASSERT(pps != NULL, ("NULL pps pointer in pps_capture"));
th = timehands;
- pps->capgen = th->th_generation;
+ pps->capgen = tc_getgen(th);
pps->capth = th;
#ifdef FFCLOCK
pps->capffth = fftimehands;
#endif
pps->capcount = th->th_counter->tc_get_timecount(th->th_counter);
- if (pps->capgen != th->th_generation)
+ if (pps->capgen != tc_getgen(th))
pps->capgen = 0;
}
@@ -1677,7 +1705,7 @@ pps_event(struct pps_state *pps, int event)
KASSERT(pps != NULL, ("NULL pps pointer in pps_event"));
/* If the timecounter was wound up underneath us, bail out. */
- if (pps->capgen == 0 || pps->capgen != pps->capth->th_generation)
+ if (pps->capgen == 0 || pps->capgen != tc_getgen(pps->capth))
return;
/* Things would be easier with arrays. */
@@ -1727,7 +1755,7 @@ pps_event(struct pps_state *pps, int event)
bintime2timespec(&bt, &ts);
/* If the timecounter was wound up underneath us, bail out. */
- if (pps->capgen != pps->capth->th_generation)
+ if (pps->capgen != tc_getgen(pps->capth))
return;
*pcount = pps->capcount;
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