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

* [PATCH v3 06/12] arm: vdso: Add support for CLOCK_MONOTONIC_RAW
@ 2017-10-27 22:25 ` Mark Salyzyn
  0 siblings, 0 replies; 2+ messages in thread
From: Mark Salyzyn @ 2017-10-27 22:25 UTC (permalink / raw)
  To: linux-kernel
  Cc: Mark Salyzyn, James Morse, Russell King, Catalin Marinas,
	Will Deacon, Andy Lutomirski, Dmitry Safonov, John Stultz,
	Mark Rutland, Laura Abbott, Kees Cook, Ard Biesheuvel,
	Andy Gross, Kevin Brodsky, Andrew Pinski, linux-arm-kernel,
	Mark Salyzyn

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@android.com>
Cc: James Morse <james.morse@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dmitry Safonov <dsafonov@virtuozzo.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Andy Gross <andy.gross@linaro.org>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Andrew Pinski <apinski@cavium.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org

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

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