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Commit 12ba6c99 authored by Mike Travis's avatar Mike Travis Committed by Ingo Molnar
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x86/UV: Add kdump to UV NMI handler 



If a system has hung and it no longer responds to external
events, this patch adds the capability of doing a standard kdump
and system reboot then triggered by the system NMI command.

It is enabled when the nmi action is changed to "kdump" and the
kernel is built with CONFIG_KEXEC enabled.

Signed-off-by: default avatarMike Travis <travis@sgi.com>
Reviewed-by: default avatarDimitri Sivanich <sivanich@sgi.com>
Reviewed-by: default avatarHedi Berriche <hedi@sgi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jason Wessel <jason.wessel@windriver.com>
Link: http://lkml.kernel.org/r/20130923212500.660567460@asylum.americas.sgi.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 3c121d9a

arch/x86/platform/uv/uv_nmi.c

+41 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 


#include <linux/cpu.h>

#include <linux/delay.h>

#include <linux/kexec.h>

#include <linux/module.h>

#include <linux/nmi.h>

#include <linux/sched.h>
@@ -70,6 +71,7 @@ static atomic_t uv_in_nmi; 
static atomic_t uv_nmi_cpu = ATOMIC_INIT(-1);

static atomic_t uv_nmi_cpus_in_nmi = ATOMIC_INIT(-1);

static atomic_t uv_nmi_slave_continue;

static atomic_t uv_nmi_kexec_failed;

static cpumask_var_t uv_nmi_cpu_mask;



/* Values for uv_nmi_slave_continue */
@@ -143,6 +145,7 @@ module_param_named(retry_count, uv_nmi_retry_count, int, 0644); 
 * Valid NMI Actions:

 *  "dump"	- dump process stack for each cpu

 *  "ips"	- dump IP info for each cpu

 *  "kdump"	- do crash dump

 */

static char uv_nmi_action[8] = "dump";

module_param_string(action, uv_nmi_action, sizeof(uv_nmi_action), 0644);
@@ -496,6 +499,40 @@ static void uv_nmi_touch_watchdogs(void) 
	touch_nmi_watchdog();

}



#if defined(CONFIG_KEXEC)

static void uv_nmi_kdump(int cpu, int master, struct pt_regs *regs)

{

	/* Call crash to dump system state */

	if (master) {

		pr_emerg("UV: NMI executing crash_kexec on CPU%d\n", cpu);

		crash_kexec(regs);



		pr_emerg("UV: crash_kexec unexpectedly returned, ");

		if (!kexec_crash_image) {

			pr_cont("crash kernel not loaded\n");

			atomic_set(&uv_nmi_kexec_failed, 1);

			uv_nmi_sync_exit(1);

			return;

		}

		pr_cont("kexec busy, stalling cpus while waiting\n");

	}



	/* If crash exec fails the slaves should return, otherwise stall */

	while (atomic_read(&uv_nmi_kexec_failed) == 0)

		mdelay(10);



	/* Crash kernel most likely not loaded, return in an orderly fashion */

	uv_nmi_sync_exit(0);

}



#else /* !CONFIG_KEXEC */

static inline void uv_nmi_kdump(int cpu, int master, struct pt_regs *regs)

{

	if (master)

		pr_err("UV: NMI kdump: KEXEC not supported in this kernel\n");

}

#endif /* !CONFIG_KEXEC */



/*

 * UV NMI handler

 */
@@ -517,6 +554,10 @@ int uv_handle_nmi(unsigned int reason, struct pt_regs *regs) 
	/* Indicate we are the first CPU into the NMI handler */

	master = (atomic_read(&uv_nmi_cpu) == cpu);



	/* If NMI action is "kdump", then attempt to do it */

	if (uv_nmi_action_is("kdump"))

		uv_nmi_kdump(cpu, master, regs);



	/* Pause as all cpus enter the NMI handler */

	uv_nmi_wait(master);