[PATCH v3 06/12] arm: vdso: Add support for CLOCK_MONOTONIC_RAW

From: Mark Salyzyn
Date: Fri Oct 27 2017 - 18:26:11 EST


Add a case for CLOCK_MONOTONIC_RAW to match up with support that
is available in arm64's vdso.

Signed-off-by: Mark Salyzyn <salyzyn@xxxxxxxxxxx>
Cc: James Morse <james.morse@xxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Dmitry Safonov <dsafonov@xxxxxxxxxxxxx>
Cc: John Stultz <john.stultz@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Laura Abbott <labbott@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Andy Gross <andy.gross@xxxxxxxxxx>
Cc: Kevin Brodsky <kevin.brodsky@xxxxxxx>
Cc: Andrew Pinski <apinski@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx

v2:
- split first CL into 6 of 7 pieces

v3:
- rebase (unchanged)

---
arch/arm/include/asm/vdso_datapage.h | 4 +++
arch/arm/kernel/vdso.c | 5 ++++
arch/arm/vdso/vgettimeofday.c | 51 ++++++++++++++++++++++++++++++++++++
3 files changed, 60 insertions(+)

diff --git a/arch/arm/include/asm/vdso_datapage.h b/arch/arm/include/asm/vdso_datapage.h
index fa3e1856244d..d57c296f7f52 100644
--- a/arch/arm/include/asm/vdso_datapage.h
+++ b/arch/arm/include/asm/vdso_datapage.h
@@ -46,6 +46,10 @@ struct vdso_data {
u64 xtime_clock_snsec; /* CLOCK_REALTIME sub-ns base */
u32 tz_minuteswest; /* timezone info for gettimeofday(2) */
u32 tz_dsttime;
+
+ u32 cs_raw_mult; /* Raw clocksource multipler */
+ u32 raw_time_sec; /* Raw time */
+ u32 raw_time_nsec;
};

union vdso_data_store {
diff --git a/arch/arm/kernel/vdso.c b/arch/arm/kernel/vdso.c
index aed84b659cc5..7377638a3b00 100644
--- a/arch/arm/kernel/vdso.c
+++ b/arch/arm/kernel/vdso.c
@@ -335,9 +335,14 @@ void update_vsyscall(struct timekeeper *tk)

if (!vdso_data->use_syscall) {
vdso_data->cs_cycle_last = tk->tkr_mono.cycle_last;
+ vdso_data->raw_time_sec = tk->raw_time.tv_sec;
+ vdso_data->raw_time_nsec = (tk->raw_time.tv_nsec <<
+ tk->raw_time.shift) +
+ tk->tkr_raw.xtime_nsec;
vdso_data->xtime_clock_sec = tk->xtime_sec;
vdso_data->xtime_clock_snsec = tk->tkr_mono.xtime_nsec;
vdso_data->cs_mono_mult = tk->tkr_mono.mult;
+ vdso_data->cs_raw_mult = tk->tkr_raw.mult;
/* tkr_mono.shift == tkr_raw.shift */
vdso_data->cs_shift = tk->tkr_mono.shift;
vdso_data->cs_mask = tk->tkr_mono.mask;
diff --git a/arch/arm/vdso/vgettimeofday.c b/arch/arm/vdso/vgettimeofday.c
index 7fcc8cfcb7df..b374c143d53e 100644
--- a/arch/arm/vdso/vgettimeofday.c
+++ b/arch/arm/vdso/vgettimeofday.c
@@ -206,6 +206,47 @@ static __always_inline notrace int do_monotonic(const struct vdso_data *vd,
return 0;
}

+static __always_inline notrace int do_monotonic_raw(const struct vdso_data *vd,
+ struct timespec *ts)
+{
+ u32 seq, mult, shift;
+ u64 nsec, cycle_last;
+#ifdef ARCH_CLOCK_FIXED_MASK
+ static const u64 mask = ARCH_CLOCK_FIXED_MASK;
+#else
+ u64 mask;
+#endif
+
+ typeof(((struct vdso_data *)vd)->raw_time_sec) sec;
+
+ do {
+ seq = vdso_read_begin(vd);
+
+ if (vd->use_syscall)
+ return -1;
+
+ cycle_last = vd->cs_cycle_last;
+
+ mult = vd->cs_raw_mult;
+ shift = vd->cs_shift;
+#ifndef ARCH_CLOCK_FIXED_MASK
+ mask = vd->cs_mask;
+#endif
+
+ sec = vd->raw_time_sec;
+ nsec = vd->raw_time_nsec;
+
+ } while (unlikely(vdso_read_retry(vd, seq)));
+
+ nsec += get_clock_shifted_nsec(cycle_last, mult, mask);
+ nsec >>= shift;
+ /* open coding timespec_add_ns to save a ts->tv_nsec = 0 */
+ ts->tv_sec = sec + __iter_div_u64_rem(nsec, NSEC_PER_SEC, &nsec);
+ ts->tv_nsec = nsec;
+
+ return 0;
+}
+
#else /* CONFIG_ARM_ARCH_TIMER */

static notrace int do_realtime(const struct vdso_data *vd, struct timespec *ts)
@@ -218,6 +259,12 @@ static notrace int do_monotonic(const struct vdso_data *vd, struct timespec *ts)
return -1;
}

+static notrace int do_monotonic_raw(const struct vdso_data *vd,
+ struct timespec *ts)
+{
+ return -1;
+}
+
#endif /* CONFIG_ARM_ARCH_TIMER */

notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
@@ -239,6 +286,10 @@ notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
if (do_monotonic(vd, ts))
goto fallback;
break;
+ case CLOCK_MONOTONIC_RAW:
+ if (do_monotonic_raw(vd, ts))
+ goto fallback;
+ break;
default:
goto fallback;
}
--
2.15.0.rc2.357.g7e34df9404-goog