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Subject[PATCH v4.16-rc5 1/3] x86/vdso: on Intel, VDSO should handle CLOCK_MONOTONIC_RAW
Date
diff --git a/arch/x86/entry/vdso/vclock_gettime.c b/arch/x86/entry/vdso/vclock_gettime.c
index f19856d..fbc7371 100644
--- a/arch/x86/entry/vdso/vclock_gettime.c
+++ b/arch/x86/entry/vdso/vclock_gettime.c
@@ -182,6 +182,18 @@ notrace static u64 vread_tsc(void)
return last;
}

+notrace static u64 vread_tsc_raw(void)
+{
+ u64 tsc
+ , last = gtod->raw_cycle_last;
+
+ tsc = rdtsc_ordered();
+ if (likely(tsc >= last))
+ return tsc;
+ asm volatile ("");
+ return last;
+}
+
notrace static inline u64 vgetsns(int *mode)
{
u64 v;
@@ -203,6 +215,27 @@ notrace static inline u64 vgetsns(int *mode)
return v * gtod->mult;
}

+notrace static inline u64 vgetsns_raw(int *mode)
+{
+ u64 v;
+ cycles_t cycles;
+
+ if (gtod->vclock_mode == VCLOCK_TSC)
+ cycles = vread_tsc_raw();
+#ifdef CONFIG_PARAVIRT_CLOCK
+ else if (gtod->vclock_mode == VCLOCK_PVCLOCK)
+ cycles = vread_pvclock(mode);
+#endif
+#ifdef CONFIG_HYPERV_TSCPAGE
+ else if (gtod->vclock_mode == VCLOCK_HVCLOCK)
+ cycles = vread_hvclock(mode);
+#endif
+ else
+ return 0;
+ v = (cycles - gtod->raw_cycle_last) & gtod->raw_mask;
+ return v * gtod->raw_mult;
+}
+
/* Code size doesn't matter (vdso is 4k anyway) and this is faster. */
notrace static int __always_inline do_realtime(struct timespec *ts)
{
@@ -246,6 +279,27 @@ notrace static int __always_inline do_monotonic(struct timespec *ts)
return mode;
}

+notrace static __always_inline int do_monotonic_raw(struct timespec *ts)
+{
+ unsigned long seq;
+ u64 ns;
+ int mode;
+
+ do {
+ seq = gtod_read_begin(gtod);
+ mode = gtod->vclock_mode;
+ ts->tv_sec = gtod->monotonic_time_raw_sec;
+ ns = gtod->monotonic_time_raw_nsec;
+ ns += vgetsns_raw(&mode);
+ ns >>= gtod->raw_shift;
+ } while (unlikely(gtod_read_retry(gtod, seq)));
+
+ ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
+ ts->tv_nsec = ns;
+
+ return mode;
+}
+
notrace static void do_realtime_coarse(struct timespec *ts)
{
unsigned long seq;
@@ -277,6 +331,10 @@ notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
if (do_monotonic(ts) == VCLOCK_NONE)
goto fallback;
break;
+ case CLOCK_MONOTONIC_RAW:
+ if (do_monotonic_raw(ts) == VCLOCK_NONE)
+ goto fallback;
+ break;
case CLOCK_REALTIME_COARSE:
do_realtime_coarse(ts);
break;
diff --git a/arch/x86/entry/vsyscall/vsyscall_gtod.c b/arch/x86/entry/vsyscall/vsyscall_gtod.c
index e1216dd..5af7093 100644
--- a/arch/x86/entry/vsyscall/vsyscall_gtod.c
+++ b/arch/x86/entry/vsyscall/vsyscall_gtod.c
@@ -45,6 +45,11 @@ void update_vsyscall(struct timekeeper *tk)
vdata->mult = tk->tkr_mono.mult;
vdata->shift = tk->tkr_mono.shift;

+ vdata->raw_cycle_last = tk->tkr_raw.cycle_last;
+ vdata->raw_mask = tk->tkr_raw.mask;
+ vdata->raw_mult = tk->tkr_raw.mult;
+ vdata->raw_shift = tk->tkr_raw.shift;
+
vdata->wall_time_sec = tk->xtime_sec;
vdata->wall_time_snsec = tk->tkr_mono.xtime_nsec;

@@ -74,5 +79,8 @@ void update_vsyscall(struct timekeeper *tk)
vdata->monotonic_time_coarse_sec++;
}

+ vdata->monotonic_time_raw_sec = tk->raw_sec;
+ vdata->monotonic_time_raw_nsec = tk->tkr_raw.xtime_nsec;
+
gtod_write_end(vdata);
}
diff --git a/arch/x86/include/asm/vgtod.h b/arch/x86/include/asm/vgtod.h
index fb856c9..24e4d45 100644
--- a/arch/x86/include/asm/vgtod.h
+++ b/arch/x86/include/asm/vgtod.h
@@ -22,6 +22,10 @@ struct vsyscall_gtod_data {
u64 mask;
u32 mult;
u32 shift;
+ u64 raw_cycle_last;
+ u64 raw_mask;
+ u32 raw_mult;
+ u32 raw_shift;

/* open coded 'struct timespec' */
u64 wall_time_snsec;
@@ -32,6 +36,8 @@ struct vsyscall_gtod_data {
gtod_long_t wall_time_coarse_nsec;
gtod_long_t monotonic_time_coarse_sec;
gtod_long_t monotonic_time_coarse_nsec;
+ gtod_long_t monotonic_time_raw_sec;
+ gtod_long_t monotonic_time_raw_nsec;

int tz_minuteswest;
int tz_dsttime;
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