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-rw-r--r--lib/vdso/Kconfig6
-rw-r--r--lib/vdso/gettimeofday.c204
2 files changed, 170 insertions, 40 deletions
diff --git a/lib/vdso/Kconfig b/lib/vdso/Kconfig
index 9fe698ff62ec..d883ac299508 100644
--- a/lib/vdso/Kconfig
+++ b/lib/vdso/Kconfig
@@ -24,4 +24,10 @@ config GENERIC_COMPAT_VDSO
help
This config option enables the compat VDSO layer.
+config GENERIC_VDSO_TIME_NS
+ bool
+ help
+ Selected by architectures which support time namespaces in the
+ VDSO
+
endif
diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c
index 42bd8ab955fa..f8b8ec5e63ac 100644
--- a/lib/vdso/gettimeofday.c
+++ b/lib/vdso/gettimeofday.c
@@ -38,12 +38,22 @@ u64 vdso_calc_delta(u64 cycles, u64 last, u64 mask, u32 mult)
}
#endif
-static int do_hres(const struct vdso_data *vd, clockid_t clk,
- struct __kernel_timespec *ts)
+#ifdef CONFIG_TIME_NS
+static int do_hres_timens(const struct vdso_data *vdns, clockid_t clk,
+ struct __kernel_timespec *ts)
{
- const struct vdso_timestamp *vdso_ts = &vd->basetime[clk];
- u64 cycles, last, sec, ns;
+ const struct vdso_data *vd = __arch_get_timens_vdso_data();
+ const struct timens_offset *offs = &vdns->offset[clk];
+ const struct vdso_timestamp *vdso_ts;
+ u64 cycles, last, ns;
u32 seq;
+ s64 sec;
+
+ if (clk != CLOCK_MONOTONIC_RAW)
+ vd = &vd[CS_HRES_COARSE];
+ else
+ vd = &vd[CS_RAW];
+ vdso_ts = &vd->basetime[clk];
do {
seq = vdso_read_begin(vd);
@@ -58,6 +68,10 @@ static int do_hres(const struct vdso_data *vd, clockid_t clk,
sec = vdso_ts->sec;
} while (unlikely(vdso_read_retry(vd, seq)));
+ /* Add the namespace offset */
+ sec += offs->sec;
+ ns += offs->nsec;
+
/*
* Do this outside the loop: a race inside the loop could result
* in __iter_div_u64_rem() being extremely slow.
@@ -67,18 +81,128 @@ static int do_hres(const struct vdso_data *vd, clockid_t clk,
return 0;
}
+#else
+static __always_inline const struct vdso_data *__arch_get_timens_vdso_data(void)
+{
+ return NULL;
+}
+
+static int do_hres_timens(const struct vdso_data *vdns, clockid_t clk,
+ struct __kernel_timespec *ts)
+{
+ return -EINVAL;
+}
+#endif
-static void do_coarse(const struct vdso_data *vd, clockid_t clk,
- struct __kernel_timespec *ts)
+static __always_inline int do_hres(const struct vdso_data *vd, clockid_t clk,
+ struct __kernel_timespec *ts)
{
const struct vdso_timestamp *vdso_ts = &vd->basetime[clk];
+ u64 cycles, last, sec, ns;
u32 seq;
do {
+ /*
+ * Open coded to handle VCLOCK_TIMENS. Time namespace
+ * enabled tasks have a special VVAR page installed which
+ * has vd->seq set to 1 and vd->clock_mode set to
+ * VCLOCK_TIMENS. For non time namespace affected tasks
+ * this does not affect performance because if vd->seq is
+ * odd, i.e. a concurrent update is in progress the extra
+ * check for vd->clock_mode is just a few extra
+ * instructions while spin waiting for vd->seq to become
+ * even again.
+ */
+ while (unlikely((seq = READ_ONCE(vd->seq)) & 1)) {
+ if (IS_ENABLED(CONFIG_TIME_NS) &&
+ vd->clock_mode == VCLOCK_TIMENS)
+ return do_hres_timens(vd, clk, ts);
+ cpu_relax();
+ }
+ smp_rmb();
+
+ cycles = __arch_get_hw_counter(vd->clock_mode);
+ ns = vdso_ts->nsec;
+ last = vd->cycle_last;
+ if (unlikely((s64)cycles < 0))
+ return -1;
+
+ ns += vdso_calc_delta(cycles, last, vd->mask, vd->mult);
+ ns >>= vd->shift;
+ sec = vdso_ts->sec;
+ } while (unlikely(vdso_read_retry(vd, seq)));
+
+ /*
+ * Do this outside the loop: a race inside the loop could result
+ * in __iter_div_u64_rem() being extremely slow.
+ */
+ ts->tv_sec = sec + __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
+ ts->tv_nsec = ns;
+
+ return 0;
+}
+
+#ifdef CONFIG_TIME_NS
+static int do_coarse_timens(const struct vdso_data *vdns, clockid_t clk,
+ struct __kernel_timespec *ts)
+{
+ const struct vdso_data *vd = __arch_get_timens_vdso_data();
+ const struct vdso_timestamp *vdso_ts = &vd->basetime[clk];
+ const struct timens_offset *offs = &vdns->offset[clk];
+ u64 nsec;
+ s64 sec;
+ s32 seq;
+
+ do {
seq = vdso_read_begin(vd);
+ sec = vdso_ts->sec;
+ nsec = vdso_ts->nsec;
+ } while (unlikely(vdso_read_retry(vd, seq)));
+
+ /* Add the namespace offset */
+ sec += offs->sec;
+ nsec += offs->nsec;
+
+ /*
+ * Do this outside the loop: a race inside the loop could result
+ * in __iter_div_u64_rem() being extremely slow.
+ */
+ ts->tv_sec = sec + __iter_div_u64_rem(nsec, NSEC_PER_SEC, &nsec);
+ ts->tv_nsec = nsec;
+ return 0;
+}
+#else
+static int do_coarse_timens(const struct vdso_data *vdns, clockid_t clk,
+ struct __kernel_timespec *ts)
+{
+ return -1;
+}
+#endif
+
+static __always_inline int do_coarse(const struct vdso_data *vd, clockid_t clk,
+ struct __kernel_timespec *ts)
+{
+ const struct vdso_timestamp *vdso_ts = &vd->basetime[clk];
+ u32 seq;
+
+ do {
+ /*
+ * Open coded to handle VCLOCK_TIMENS. See comment in
+ * do_hres().
+ */
+ while ((seq = READ_ONCE(vd->seq)) & 1) {
+ if (IS_ENABLED(CONFIG_TIME_NS) &&
+ vd->clock_mode == VCLOCK_TIMENS)
+ return do_coarse_timens(vd, clk, ts);
+ cpu_relax();
+ }
+ smp_rmb();
+
ts->tv_sec = vdso_ts->sec;
ts->tv_nsec = vdso_ts->nsec;
} while (unlikely(vdso_read_retry(vd, seq)));
+
+ return 0;
}
static __maybe_unused int
@@ -96,15 +220,16 @@ __cvdso_clock_gettime_common(clockid_t clock, struct __kernel_timespec *ts)
* clocks are handled in the VDSO directly.
*/
msk = 1U << clock;
- if (likely(msk & VDSO_HRES)) {
- return do_hres(&vd[CS_HRES_COARSE], clock, ts);
- } else if (msk & VDSO_COARSE) {
- do_coarse(&vd[CS_HRES_COARSE], clock, ts);
- return 0;
- } else if (msk & VDSO_RAW) {
- return do_hres(&vd[CS_RAW], clock, ts);
- }
- return -1;
+ if (likely(msk & VDSO_HRES))
+ vd = &vd[CS_HRES_COARSE];
+ else if (msk & VDSO_COARSE)
+ return do_coarse(&vd[CS_HRES_COARSE], clock, ts);
+ else if (msk & VDSO_RAW)
+ vd = &vd[CS_RAW];
+ else
+ return -1;
+
+ return do_hres(vd, clock, ts);
}
static __maybe_unused int
@@ -117,6 +242,7 @@ __cvdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts)
return 0;
}
+#ifdef BUILD_VDSO32
static __maybe_unused int
__cvdso_clock_gettime32(clockid_t clock, struct old_timespec32 *res)
{
@@ -125,20 +251,16 @@ __cvdso_clock_gettime32(clockid_t clock, struct old_timespec32 *res)
ret = __cvdso_clock_gettime_common(clock, &ts);
-#ifdef VDSO_HAS_32BIT_FALLBACK
if (unlikely(ret))
return clock_gettime32_fallback(clock, res);
-#else
- if (unlikely(ret))
- ret = clock_gettime_fallback(clock, &ts);
-#endif
- if (likely(!ret)) {
- res->tv_sec = ts.tv_sec;
- res->tv_nsec = ts.tv_nsec;
- }
+ /* For ret == 0 */
+ res->tv_sec = ts.tv_sec;
+ res->tv_nsec = ts.tv_nsec;
+
return ret;
}
+#endif /* BUILD_VDSO32 */
static __maybe_unused int
__cvdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
@@ -156,6 +278,10 @@ __cvdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
}
if (unlikely(tz != NULL)) {
+ if (IS_ENABLED(CONFIG_TIME_NS) &&
+ vd->clock_mode == VCLOCK_TIMENS)
+ vd = __arch_get_timens_vdso_data();
+
tz->tz_minuteswest = vd[CS_HRES_COARSE].tz_minuteswest;
tz->tz_dsttime = vd[CS_HRES_COARSE].tz_dsttime;
}
@@ -167,7 +293,12 @@ __cvdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
static __maybe_unused __kernel_old_time_t __cvdso_time(__kernel_old_time_t *time)
{
const struct vdso_data *vd = __arch_get_vdso_data();
- __kernel_old_time_t t = READ_ONCE(vd[CS_HRES_COARSE].basetime[CLOCK_REALTIME].sec);
+ __kernel_old_time_t t;
+
+ if (IS_ENABLED(CONFIG_TIME_NS) && vd->clock_mode == VCLOCK_TIMENS)
+ vd = __arch_get_timens_vdso_data();
+
+ t = READ_ONCE(vd[CS_HRES_COARSE].basetime[CLOCK_REALTIME].sec);
if (time)
*time = t;
@@ -181,7 +312,6 @@ static __maybe_unused
int __cvdso_clock_getres_common(clockid_t clock, struct __kernel_timespec *res)
{
const struct vdso_data *vd = __arch_get_vdso_data();
- u64 hrtimer_res;
u32 msk;
u64 ns;
@@ -189,27 +319,24 @@ int __cvdso_clock_getres_common(clockid_t clock, struct __kernel_timespec *res)
if (unlikely((u32) clock >= MAX_CLOCKS))
return -1;
- hrtimer_res = READ_ONCE(vd[CS_HRES_COARSE].hrtimer_res);
+ if (IS_ENABLED(CONFIG_TIME_NS) && vd->clock_mode == VCLOCK_TIMENS)
+ vd = __arch_get_timens_vdso_data();
+
/*
* Convert the clockid to a bitmask and use it to check which
* clocks are handled in the VDSO directly.
*/
msk = 1U << clock;
- if (msk & VDSO_HRES) {
+ if (msk & (VDSO_HRES | VDSO_RAW)) {
/*
* Preserves the behaviour of posix_get_hrtimer_res().
*/
- ns = hrtimer_res;
+ ns = READ_ONCE(vd[CS_HRES_COARSE].hrtimer_res);
} else if (msk & VDSO_COARSE) {
/*
* Preserves the behaviour of posix_get_coarse_res().
*/
ns = LOW_RES_NSEC;
- } else if (msk & VDSO_RAW) {
- /*
- * Preserves the behaviour of posix_get_hrtimer_res().
- */
- ns = hrtimer_res;
} else {
return -1;
}
@@ -231,6 +358,7 @@ int __cvdso_clock_getres(clockid_t clock, struct __kernel_timespec *res)
return 0;
}
+#ifdef BUILD_VDSO32
static __maybe_unused int
__cvdso_clock_getres_time32(clockid_t clock, struct old_timespec32 *res)
{
@@ -239,18 +367,14 @@ __cvdso_clock_getres_time32(clockid_t clock, struct old_timespec32 *res)
ret = __cvdso_clock_getres_common(clock, &ts);
-#ifdef VDSO_HAS_32BIT_FALLBACK
if (unlikely(ret))
return clock_getres32_fallback(clock, res);
-#else
- if (unlikely(ret))
- ret = clock_getres_fallback(clock, &ts);
-#endif
- if (likely(!ret && res)) {
+ if (likely(res)) {
res->tv_sec = ts.tv_sec;
res->tv_nsec = ts.tv_nsec;
}
return ret;
}
+#endif /* BUILD_VDSO32 */
#endif /* VDSO_HAS_CLOCK_GETRES */
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-19 05:24:28 +0300