From 8f932b99a057af75a5e019abfbf8f9cf769b46b4 Mon Sep 17 00:00:00 2001 From: Mark Salyzyn Date: Thu, 17 Aug 2017 09:16:27 -0700 Subject: [PATCH] FROMLIST: [PATCH v6 05/12] arm: vdso: Add support for CLOCK_MONOTONIC_RAW (cherry pick from url https://patchwork.kernel.org/patch/10052099/) Take an effort to recode the arm64 vdso code from assembler to C previously submitted by Andrew Pinski , rework it for use in both arm and arm64, overlapping any optimizations for each architecture. But instead of landing it in arm64, land the result into lib/vdso and unify both implementations to simplify future maintenance. Add a case for CLOCK_MONOTONIC_RAW to match up with support that is available in arm64's vdso. Signed-off-by: Mark Salyzyn Cc: James Morse Cc: Russell King Cc: Catalin Marinas Cc: Will Deacon Cc: Andy Lutomirski Cc: Dmitry Safonov Cc: John Stultz Cc: Mark Rutland Cc: Laura Abbott Cc: Kees Cook Cc: Ard Biesheuvel Cc: Andy Gross Cc: Kevin Brodsky Cc: Andrew Pinski Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Bug: 63737556 Bug: 20045882 Change-Id: If9c09d131e236ba4a483dbc122e6b876f471df72 --- arch/arm/include/asm/vdso_datapage.h | 11 +++++++ arch/arm/kernel/vdso.c | 3 ++ arch/arm/vdso/vgettimeofday.c | 44 ++++++++++++++++++++++++++++ 3 files changed, 58 insertions(+) diff --git a/arch/arm/include/asm/vdso_datapage.h b/arch/arm/include/asm/vdso_datapage.h index 8dd7303db4ec..1c6e6a5d5d9d 100644 --- a/arch/arm/include/asm/vdso_datapage.h +++ b/arch/arm/include/asm/vdso_datapage.h @@ -34,6 +34,11 @@ typedef u32 vdso_wtm_clock_nsec_t; typedef u32 vdso_xtime_clock_sec_t; #endif +#ifndef _VDSO_RAW_TIME_SEC_T +#define _VDSO_RAW_TIME_SEC_T +typedef u32 vdso_raw_time_sec_t; +#endif + /* Try to be cache-friendly on systems that don't implement the * generic timer: fit the unconditionally updated fields in the first * 32 bytes. @@ -58,6 +63,12 @@ struct vdso_data { u64 xtime_clock_snsec; /* CLOCK_REALTIME sub-ns base */ u32 tz_minuteswest; /* timezone info for gettimeofday(2) */ u32 tz_dsttime; + + /* Raw clocksource multipler */ + u32 cs_raw_mult; + /* Raw time */ + vdso_raw_time_sec_t raw_time_sec; + u32 raw_time_nsec; }; union vdso_data_store { diff --git a/arch/arm/kernel/vdso.c b/arch/arm/kernel/vdso.c index d3c2a82a588b..8d35bbcb931e 100644 --- a/arch/arm/kernel/vdso.c +++ b/arch/arm/kernel/vdso.c @@ -320,9 +320,12 @@ 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_sec; + vdso_data->raw_time_nsec = 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 59893fca03b3..a2c4db83edc4 100644 --- a/arch/arm/vdso/vgettimeofday.c +++ b/arch/arm/vdso/vgettimeofday.c @@ -194,6 +194,40 @@ static notrace int do_monotonic(const struct vdso_data *vd, struct timespec *ts) return 0; } +static notrace int do_monotonic_raw(const struct vdso_data *vd, + struct timespec *ts) +{ + u32 seq, mult, shift; + u64 nsec, cycle_last; + u64 mask; + vdso_raw_time_sec_t 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; + mask = vd->cs_mask; + + 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) @@ -206,6 +240,12 @@ 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) @@ -227,6 +267,10 @@ 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; } -- 2.20.1