From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757344Ab2IQWFj (ORCPT ); Mon, 17 Sep 2012 18:05:39 -0400 Received: from e4.ny.us.ibm.com ([32.97.182.144]:45856 "EHLO e4.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757325Ab2IQWFX (ORCPT ); Mon, 17 Sep 2012 18:05:23 -0400 From: John Stultz To: linux-kernel Cc: John Stultz , Tony Luck , Paul Mackerras , Benjamin Herrenschmidt , Andy Lutomirski , Martin Schwidefsky , Paul Turner , Steven Rostedt , Richard Cochran , Prarit Bhargava , Thomas Gleixner Subject: [PATCH 6/6][RFC] time: Convert x86_64 to using new update_vsyscall Date: Mon, 17 Sep 2012 18:05:01 -0400 Message-Id: <1347919501-64534-7-git-send-email-john.stultz@linaro.org> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1347919501-64534-1-git-send-email-john.stultz@linaro.org> References: <1347919501-64534-1-git-send-email-john.stultz@linaro.org> x-cbid: 12091722-3534-0000-0000-00000CD52F25 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Switch x86_64 to using sub-ns precise vsyscall Cc: Tony Luck Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Andy Lutomirski Cc: Martin Schwidefsky Cc: Paul Turner Cc: Steven Rostedt Cc: Richard Cochran Cc: Prarit Bhargava Cc: Thomas Gleixner Signed-off-by: John Stultz --- arch/x86/Kconfig | 2 +- arch/x86/include/asm/vgtod.h | 4 ++-- arch/x86/kernel/vsyscall_64.c | 47 ++++++++++++++++++++++++---------------- arch/x86/vdso/vclock_gettime.c | 22 ++++++++++++------- 4 files changed, 45 insertions(+), 30 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index e3f3c1a..8ec3a1a 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -93,7 +93,7 @@ config X86 select GENERIC_CLOCKEVENTS select ARCH_CLOCKSOURCE_DATA if X86_64 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) - select GENERIC_TIME_VSYSCALL_OLD if X86_64 + select GENERIC_TIME_VSYSCALL if X86_64 select KTIME_SCALAR if X86_32 select GENERIC_STRNCPY_FROM_USER select GENERIC_STRNLEN_USER diff --git a/arch/x86/include/asm/vgtod.h b/arch/x86/include/asm/vgtod.h index 8b38be2..46e24d3 100644 --- a/arch/x86/include/asm/vgtod.h +++ b/arch/x86/include/asm/vgtod.h @@ -17,8 +17,8 @@ struct vsyscall_gtod_data { /* open coded 'struct timespec' */ time_t wall_time_sec; - u32 wall_time_nsec; - u32 monotonic_time_nsec; + u64 wall_time_snsec; + u64 monotonic_time_snsec; time_t monotonic_time_sec; struct timezone sys_tz; diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c index 77dde29..3a3e8c9 100644 --- a/arch/x86/kernel/vsyscall_64.c +++ b/arch/x86/kernel/vsyscall_64.c @@ -82,32 +82,41 @@ void update_vsyscall_tz(void) vsyscall_gtod_data.sys_tz = sys_tz; } -void update_vsyscall_old(struct timespec *wall_time, struct timespec *wtm, - struct clocksource *clock, u32 mult) +void update_vsyscall(struct timekeeper *tk) { - struct timespec monotonic; + struct vsyscall_gtod_data *vdata = &vsyscall_gtod_data; - write_seqcount_begin(&vsyscall_gtod_data.seq); + write_seqcount_begin(&vdata->seq); /* copy vsyscall data */ - vsyscall_gtod_data.clock.vclock_mode = clock->archdata.vclock_mode; - vsyscall_gtod_data.clock.cycle_last = clock->cycle_last; - vsyscall_gtod_data.clock.mask = clock->mask; - vsyscall_gtod_data.clock.mult = mult; - vsyscall_gtod_data.clock.shift = clock->shift; - - vsyscall_gtod_data.wall_time_sec = wall_time->tv_sec; - vsyscall_gtod_data.wall_time_nsec = wall_time->tv_nsec; + vdata->clock.vclock_mode = tk->clock->archdata.vclock_mode; + vdata->clock.cycle_last = tk->clock->cycle_last; + vdata->clock.mask = tk->clock->mask; + vdata->clock.mult = tk->mult; + vdata->clock.shift = tk->shift; + + vdata->wall_time_sec = tk->xtime_sec; + vdata->wall_time_snsec = tk->xtime_nsec; + + vdata->monotonic_time_sec = tk->xtime_sec + + tk->wall_to_monotonic.tv_sec; + vdata->monotonic_time_snsec = tk->xtime_nsec + + (tk->wall_to_monotonic.tv_nsec + << tk->shift); + while (vdata->monotonic_time_snsec >= + (((u64)NSEC_PER_SEC) << tk->shift)) { + vdata->monotonic_time_snsec -= + ((u64)NSEC_PER_SEC) << tk->shift; + vdata->monotonic_time_sec++; + } - monotonic = timespec_add(*wall_time, *wtm); - vsyscall_gtod_data.monotonic_time_sec = monotonic.tv_sec; - vsyscall_gtod_data.monotonic_time_nsec = monotonic.tv_nsec; + vdata->wall_time_coarse.tv_sec = tk->xtime_sec; + vdata->wall_time_coarse.tv_nsec = (long)(tk->xtime_nsec >> tk->shift); - vsyscall_gtod_data.wall_time_coarse = __current_kernel_time(); - vsyscall_gtod_data.monotonic_time_coarse = - timespec_add(vsyscall_gtod_data.wall_time_coarse, *wtm); + vdata->monotonic_time_coarse = timespec_add(vdata->wall_time_coarse, + tk->wall_to_monotonic); - write_seqcount_end(&vsyscall_gtod_data.seq); + write_seqcount_end(&vdata->seq); } static void warn_bad_vsyscall(const char *level, struct pt_regs *regs, diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c index 885eff4..4df6c37 100644 --- a/arch/x86/vdso/vclock_gettime.c +++ b/arch/x86/vdso/vclock_gettime.c @@ -80,7 +80,7 @@ notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz) } -notrace static inline long vgetns(void) +notrace static inline u64 vgetsns(void) { long v; cycles_t cycles; @@ -91,21 +91,24 @@ notrace static inline long vgetns(void) else return 0; v = (cycles - gtod->clock.cycle_last) & gtod->clock.mask; - return (v * gtod->clock.mult) >> gtod->clock.shift; + return v * gtod->clock.mult; } /* Code size doesn't matter (vdso is 4k anyway) and this is faster. */ notrace static int __always_inline do_realtime(struct timespec *ts) { - unsigned long seq, ns; + unsigned long seq; + u64 ns; int mode; + ts->tv_nsec = 0; do { seq = read_seqcount_begin(>od->seq); mode = gtod->clock.vclock_mode; ts->tv_sec = gtod->wall_time_sec; - ts->tv_nsec = gtod->wall_time_nsec; - ns = vgetns(); + ns = gtod->wall_time_snsec; + ns += vgetsns(); + ns >>= gtod->clock.shift; } while (unlikely(read_seqcount_retry(>od->seq, seq))); timespec_add_ns(ts, ns); @@ -114,15 +117,18 @@ notrace static int __always_inline do_realtime(struct timespec *ts) notrace static int do_monotonic(struct timespec *ts) { - unsigned long seq, ns; + unsigned long seq; + u64 ns; int mode; + ts->tv_nsec = 0; do { seq = read_seqcount_begin(>od->seq); mode = gtod->clock.vclock_mode; ts->tv_sec = gtod->monotonic_time_sec; - ts->tv_nsec = gtod->monotonic_time_nsec; - ns = vgetns(); + ns = gtod->monotonic_time_snsec; + ns += vgetsns(); + ns >>= gtod->clock.shift; } while (unlikely(read_seqcount_retry(>od->seq, seq))); timespec_add_ns(ts, ns); -- 1.7.9.5