Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752856AbbKJL6i (ORCPT ); Tue, 10 Nov 2015 06:58:38 -0500 Received: from smtp02.citrix.com ([66.165.176.63]:7661 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752764AbbKJL6P (ORCPT ); Tue, 10 Nov 2015 06:58:15 -0500 X-IronPort-AV: E=Sophos;i="5.20,270,1444694400"; d="scan'208";a="317031505" From: Stefano Stabellini To: CC: , , , , Stefano Stabellini Subject: [PATCH v2 6/7] xen/arm: introduce xen_read_wallclock Date: Tue, 10 Nov 2015 11:57:54 +0000 Message-ID: <1447156675-7418-6-git-send-email-stefano.stabellini@eu.citrix.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain X-DLP: MIA2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2934 Lines: 100 Read the wallclock from the shared info page at boot time. Signed-off-by: Stefano Stabellini --- Changes in v2: - properly convert arch_timer ticker to nsec - use timespec64 interfaces - use sec_hi to get a 64-bit seconds value --- arch/arm/Kconfig | 1 + arch/arm/xen/enlighten.c | 33 +++++++++++++++++++++++++++++++++ 2 files changed, 34 insertions(+) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 60be104..a9de420 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1852,6 +1852,7 @@ config XEN depends on CPU_V7 && !CPU_V6 depends on !GENERIC_ATOMIC64 depends on MMU + depends on HAVE_ARM_ARCH_TIMER select ARCH_DMA_ADDR_T_64BIT select ARM_PSCI select SWIOTLB_XEN diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c index 2f57ba3..32675b5 100644 --- a/arch/arm/xen/enlighten.c +++ b/arch/arm/xen/enlighten.c @@ -28,6 +28,8 @@ #include #include #include +#include +#include #include @@ -95,6 +97,34 @@ static unsigned long long xen_stolen_accounting(int cpu) return state.time[RUNSTATE_runnable] + state.time[RUNSTATE_offline]; } +static void xen_read_wallclock(struct timespec64 *ts) +{ + u32 version; + u64 delta; + struct timespec64 now; + struct shared_info *s = HYPERVISOR_shared_info; + struct pvclock_wall_clock *wall_clock = &(s->wc); + + /* get wallclock at system boot */ + do { + version = wall_clock->version; + rmb(); /* fetch version before time */ + now.tv_sec = ((uint64_t)wall_clock->sec_hi << 32) | wall_clock->sec; + now.tv_nsec = wall_clock->nsec; + rmb(); /* fetch time before checking version */ + } while ((wall_clock->version & 1) || (version != wall_clock->version)); + + delta = arch_timer_read_counter() * (u64)NSEC_PER_SEC; + do_div(delta, arch_timer_get_rate()); /* time since system boot */ + delta += now.tv_sec * (u64)NSEC_PER_SEC + now.tv_nsec; + + now.tv_nsec = do_div(delta, NSEC_PER_SEC); + now.tv_sec = delta; + + set_normalized_timespec64(ts, now.tv_sec, now.tv_nsec); + +} + static void xen_percpu_init(void) { struct vcpu_register_vcpu_info info; @@ -218,6 +248,7 @@ static int __init xen_guest_init(void) struct shared_info *shared_info_page = NULL; struct resource res; phys_addr_t grant_frames; + struct timespec64 ts; if (!xen_domain()) return 0; @@ -291,6 +322,8 @@ static int __init xen_guest_init(void) pv_time_ops.steal_clock = xen_stolen_accounting; static_key_slow_inc(¶virt_steal_enabled); + xen_read_wallclock(&ts); + do_settimeofday64(&ts); return 0; } -- 1.7.10.4 -- 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/