Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752486AbaJ0Fr4 (ORCPT ); Mon, 27 Oct 2014 01:47:56 -0400 Received: from mail-pd0-f171.google.com ([209.85.192.171]:45449 "EHLO mail-pd0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752408AbaJ0Fry (ORCPT ); Mon, 27 Oct 2014 01:47:54 -0400 From: "pang.xunlei" To: linux-kernel@vger.kernel.org, rtc-linux@googlegroups.com Cc: John Stultz , Thomas Gleixner , Alessandro Zummo , "pang.xunlei" Subject: [PATCH RFC 12/12] time: Convert pvclock_read_wallclock() to use timespec64 Date: Mon, 27 Oct 2014 13:46:42 +0800 Message-Id: <1414388802-5866-11-git-send-email-pang.xunlei@linaro.org> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1414388802-5866-1-git-send-email-pang.xunlei@linaro.org> References: <1414388802-5866-1-git-send-email-pang.xunlei@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The kernel uses 32-bit signed value(time_t) for seconds since 1970-01-01:00:00:00, so it will overflow at 2038-01-19 03:14:08 on 32-bit systems. We call this "2038 safety" issue. As part of addressing 2038 safety for in-kernel uses, this patch creates no functional change in existing users, converts pvclock_read_wallclock() to use timespec64 instead of timespec. Signed-off-by: pang.xunlei --- arch/x86/include/asm/pvclock.h | 2 +- arch/x86/kernel/kvmclock.c | 7 +++++-- arch/x86/kernel/pvclock.c | 8 ++++---- arch/x86/xen/time.c | 10 ++-------- 4 files changed, 12 insertions(+), 15 deletions(-) diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h index d6b078e..3323413 100644 --- a/arch/x86/include/asm/pvclock.h +++ b/arch/x86/include/asm/pvclock.h @@ -11,7 +11,7 @@ void pvclock_set_flags(u8 flags); unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src); void pvclock_read_wallclock(struct pvclock_wall_clock *wall, struct pvclock_vcpu_time_info *vcpu, - struct timespec *ts); + struct timespec64 *ts); void pvclock_resume(void); void pvclock_touch_watchdogs(void); diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index d9156ce..7cd3511 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -46,10 +46,12 @@ static struct pvclock_wall_clock wall_clock; /* * The wallclock is the time of day when we booted. Since then, some time may * have elapsed since the hypervisor wrote the data. So we try to account for - * that with system time + * that with system time. + * TODO: [2038 safety] kvm_get_wallclock() should be fixed to use timespec64. */ static void kvm_get_wallclock(struct timespec *now) { + struct timespec64 now64; struct pvclock_vcpu_time_info *vcpu_time; int low, high; int cpu; @@ -63,7 +65,8 @@ static void kvm_get_wallclock(struct timespec *now) cpu = smp_processor_id(); vcpu_time = &hv_clock[cpu].pvti; - pvclock_read_wallclock(&wall_clock, vcpu_time, now); + pvclock_read_wallclock(&wall_clock, vcpu_time, &now64); + *now = timespec64_to_timespec(now64); preempt_enable(); } diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c index 2f355d2..ae3ae07 100644 --- a/arch/x86/kernel/pvclock.c +++ b/arch/x86/kernel/pvclock.c @@ -117,17 +117,17 @@ cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src) void pvclock_read_wallclock(struct pvclock_wall_clock *wall_clock, struct pvclock_vcpu_time_info *vcpu_time, - struct timespec *ts) + struct timespec64 *ts) { u32 version; u64 delta; - struct timespec now; + struct timespec64 now; /* get wallclock at system boot */ do { version = wall_clock->version; rmb(); /* fetch version before time */ - now.tv_sec = wall_clock->sec; + now.tv_sec = (time64_t)wall_clock->sec; /* TODO: [2038 safety] wall_clock->sec uses time64_t */ now.tv_nsec = wall_clock->nsec; rmb(); /* fetch time before checking version */ } while ((wall_clock->version & 1) || (version != wall_clock->version)); @@ -138,7 +138,7 @@ void pvclock_read_wallclock(struct pvclock_wall_clock *wall_clock, now.tv_nsec = do_div(delta, NSEC_PER_SEC); now.tv_sec = delta; - set_normalized_timespec(ts, now.tv_sec, now.tv_nsec); + set_normalized_timespec64(ts, now.tv_sec, now.tv_nsec); } #ifdef CONFIG_X86_64 diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c index 2ce064a..97dd201 100644 --- a/arch/x86/xen/time.c +++ b/arch/x86/xen/time.c @@ -171,18 +171,12 @@ static cycle_t xen_clocksource_get_cycles(struct clocksource *cs) static void xen_read_wallclock(struct timespec64 *ts) { - struct timespec ts32; struct shared_info *s = HYPERVISOR_shared_info; struct pvclock_wall_clock *wall_clock = &(s->wc); - struct pvclock_vcpu_time_info *vcpu_time; + struct pvclock_vcpu_time_info *vcpu_time; vcpu_time = &get_cpu_var(xen_vcpu)->time; - /* - * TODO: [2038 safety] pvclock_read_wallclock() should be changed - * to use timespec64 for 2038 safety as soon as possible. - */ - pvclock_read_wallclock(wall_clock, vcpu_time, &ts32); - *ts = timespec_to_timespec64(ts32); + pvclock_read_wallclock(wall_clock, vcpu_time, ts); put_cpu_var(xen_vcpu); } -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/