Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750814AbVKQN06 (ORCPT ); Thu, 17 Nov 2005 08:26:58 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750802AbVKQN06 (ORCPT ); Thu, 17 Nov 2005 08:26:58 -0500 Received: from e4.ny.us.ibm.com ([32.97.182.144]:8382 "EHLO e4.ny.us.ibm.com") by vger.kernel.org with ESMTP id S1750814AbVKQN05 (ORCPT ); Thu, 17 Nov 2005 08:26:57 -0500 Date: Thu, 17 Nov 2005 18:56:59 +0530 From: Vivek Goyal To: linux kernel mailing list , Morton Andrew Morton , Fastboot mailing list Cc: ak@suse.de, "Eric W. Biederman" Subject: [PATCH 7/10] kdump: x86_64 kexec on panic Message-ID: <20051117132659.GK3981@in.ibm.com> Reply-To: vgoyal@in.ibm.com References: <20051117131339.GD3981@in.ibm.com> <20051117131825.GE3981@in.ibm.com> <20051117132004.GF3981@in.ibm.com> <20051117132138.GG3981@in.ibm.com> <20051117132315.GH3981@in.ibm.com> <20051117132437.GI3981@in.ibm.com> <20051117132557.GJ3981@in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20051117132557.GJ3981@in.ibm.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3777 Lines: 137 o Implementing the machine_crash_shutdown for x86_64 which will be called by crash_kexec (called in case of a panic, sysrq etc.). Here we do things similar to i386. Disable the interrupts, shootdown the cpus and shutdown LAPIC and IOAPIC. Changes in this version: o As the Eric's APIC initialization patches are reverted back, reintroducing LAPIC and IOAPIC shutdown. o Added some comments on CPU hotplug, modified code as suggested by Andi kleen. Signed-off-by:Murali M Chakravarthy Signed-off-by: Vivek Goyal --- linux-2.6.15-rc1-1M-dynamic-root/arch/x86_64/kernel/crash.c | 86 +++++++++++- 1 files changed, 85 insertions(+), 1 deletion(-) diff -puN arch/x86_64/kernel/crash.c~x86_64-kexec-on-panic arch/x86_64/kernel/crash.c --- linux-2.6.15-rc1-1M-dynamic/arch/x86_64/kernel/crash.c~x86_64-kexec-on-panic 2005-11-17 11:11:10.000000000 +0530 +++ linux-2.6.15-rc1-1M-dynamic-root/arch/x86_64/kernel/crash.c 2005-11-17 11:54:15.000000000 +0530 @@ -13,15 +13,85 @@ #include #include #include +#include #include #include #include #include +#include + +/* This keeps a track of which one is crashing cpu. */ +static int crashing_cpu; + +#ifdef CONFIG_SMP +static atomic_t waiting_for_crash_ipi; + +static int crash_nmi_callback(struct pt_regs *regs, int cpu) +{ + /* + * Don't do anything if this handler is invoked on crashing cpu. + * Otherwise, system will completely hang. Crashing cpu can get + * an NMI if system was initially booted with nmi_watchdog parameter. + */ + if (cpu == crashing_cpu) + return 1; + local_irq_disable(); + + disable_local_APIC(); + atomic_dec(&waiting_for_crash_ipi); + /* Assume hlt works */ + for(;;) + asm("hlt"); + + return 1; +} + +static void smp_send_nmi_allbutself(void) +{ + send_IPI_allbutself(APIC_DM_NMI); +} + +/* + * This code is a best effort heuristic to get the + * other cpus to stop executing. So races with + * cpu hotplug shouldn't matter. + */ + +static void nmi_shootdown_cpus(void) +{ + unsigned long msecs; + + atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1); + set_nmi_callback(crash_nmi_callback); + + /* + * Ensure the new callback function is set before sending + * out the NMI + */ + wmb(); + + smp_send_nmi_allbutself(); + + msecs = 1000; /* Wait at most a second for the other cpus to stop */ + while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) { + mdelay(1); + msecs--; + } + /* Leave the nmi callback set */ + disable_local_APIC(); +} +#else +static void nmi_shootdown_cpus(void) +{ + /* There are no cpus to shootdown */ +} +#endif void machine_crash_shutdown(struct pt_regs *regs) { - /* This function is only called after the system + /* + * This function is only called after the system * has paniced or is otherwise in a critical state. * The minimum amount of code to allow a kexec'd kernel * to run successfully needs to happen here. @@ -29,4 +99,18 @@ void machine_crash_shutdown(struct pt_re * In practice this means shooting down the other cpus in * an SMP system. */ + /* The kernel is broken so disable interrupts */ + local_irq_disable(); + + /* Make a note of crashing cpu. Will be used in NMI callback.*/ + crashing_cpu = smp_processor_id(); + nmi_shootdown_cpus(); + + if(cpu_has_apic) + disable_local_APIC(); + +#if defined(CONFIG_X86_IO_APIC) + disable_IO_APIC(); +#endif + } _ - 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/