Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754003AbbGWRep (ORCPT ); Thu, 23 Jul 2015 13:34:45 -0400 Received: from g9t5009.houston.hp.com ([15.240.92.67]:51092 "EHLO g9t5009.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752896AbbGWRen (ORCPT ); Thu, 23 Jul 2015 13:34:43 -0400 From: Toshi Kani To: hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com Cc: bp@alien8.de, linux-kernel@vger.kernel.org, x86@kernel.org, linux-nvdimm@ml01.01.org, Toshi Kani Subject: [PATCH] x86/panic/reboot: Flush processor caches during panic/reboot Date: Thu, 23 Jul 2015 11:33:30 -0600 Message-Id: <1437672810-9641-1-git-send-email-toshi.kani@hp.com> X-Mailer: git-send-email 2.4.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2932 Lines: 98 During power failure, Asynchronous DRAM Refresh (ADR) flushes the write buffer in memory controllers into NVDIMM, but does not flush processor caches. While the kernel and application code need to take care of processor cache flush, they may not be able to do so during panic or reboot. Add processor cache flush (wbinvd) to the stop-CPUs interfaces, native_stop_other_cpus() and nmi_shootdown_cpus(), which are called during panic and reboot as follows. These wbinvd()s are called on each CPU after its irq/APIC is disabled. - panic() + smp_send_stop() o native_stop_other_cpus() o stop_this_cpu() - native_machine_restart() - native_machine_halt() - native_machine_power_off() + native_machine_shutdown() + stop_other_cpus() o native_stop_other_cpus() o stop_this_cpu() - native_machine_crash_shutdown() + kdump_nmi_shootdown_cpus() o nmi_shootdown_cpus() o crash_nmi_callback() Note, the cpu offline path, mwait_play_dead(), already calls wbinvd(). Signed-off-by: Toshi Kani Cc: Thomas Gleixner Cc: H. Peter Anvin Cc: Ingo Molnar Cc: Borislav Petkov Cc: linux-nvdimm --- arch/x86/kernel/process.c | 2 ++ arch/x86/kernel/reboot.c | 5 +++++ arch/x86/kernel/smp.c | 2 ++ 3 files changed, 9 insertions(+) diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 397688b..3a1f381 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -320,6 +320,8 @@ void stop_this_cpu(void *dummy) set_cpu_online(smp_processor_id(), false); disable_local_APIC(); + wbinvd(); + for (;;) halt(); } diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c index 86db4bc..5ef4d4b 100644 --- a/arch/x86/kernel/reboot.c +++ b/arch/x86/kernel/reboot.c @@ -737,6 +737,9 @@ static int crash_nmi_callback(unsigned int val, struct pt_regs *regs) shootdown_callback(cpu, regs); atomic_dec(&waiting_for_crash_ipi); + + wbinvd(); + /* Assume hlt works */ halt(); for (;;) @@ -780,6 +783,8 @@ void nmi_shootdown_cpus(nmi_shootdown_cb callback) smp_send_nmi_allbutself(); + wbinvd(); + msecs = 1000; /* Wait at most a second for the other cpus to stop */ while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) { mdelay(1); diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c index 15aaa69..41e7ca8 100644 --- a/arch/x86/kernel/smp.c +++ b/arch/x86/kernel/smp.c @@ -244,6 +244,8 @@ finish: local_irq_save(flags); disable_local_APIC(); local_irq_restore(flags); + + wbinvd(); } /* -- 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/