From: Ingo Molnar <mingo@elte.hu>
Date: Wed, 17 Dec 2008 12:24:52 +0000 (+0100)
Subject: Merge branch 'x86/crashdump' into cpus4096
X-Git-Tag: v2.6.29-rc1~538^2~19
X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=855caa37b9b61c1ccfeb91a2bc04d90bfc5e4525;p=linux-2.6-omap-h63xx.git

Merge branch 'x86/crashdump' into cpus4096

Conflicts:
	arch/x86/kernel/crash.c

Merged for semantic conflict:
	arch/x86/kernel/reboot.c
---

855caa37b9b61c1ccfeb91a2bc04d90bfc5e4525
diff --cc arch/x86/kernel/reboot.c
index 0e3dbc7b2bd,c3cd512484e..ba7b9a0e606
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@@ -548,3 -517,95 +551,92 @@@ void machine_crash_shutdown(struct pt_r
  	machine_ops.crash_shutdown(regs);
  }
  #endif
+ 
+ 
+ #if defined(CONFIG_SMP)
+ 
+ /* This keeps a track of which one is crashing cpu. */
+ static int crashing_cpu;
+ static nmi_shootdown_cb shootdown_callback;
+ 
+ static atomic_t waiting_for_crash_ipi;
+ 
+ static int crash_nmi_callback(struct notifier_block *self,
+ 			unsigned long val, void *data)
+ {
+ 	int cpu;
+ 
+ 	if (val != DIE_NMI_IPI)
+ 		return NOTIFY_OK;
+ 
+ 	cpu = raw_smp_processor_id();
+ 
+ 	/* 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 NOTIFY_STOP;
+ 	local_irq_disable();
+ 
+ 	shootdown_callback(cpu, (struct die_args *)data);
+ 
+ 	atomic_dec(&waiting_for_crash_ipi);
+ 	/* Assume hlt works */
+ 	halt();
+ 	for (;;)
+ 		cpu_relax();
+ 
+ 	return 1;
+ }
+ 
+ static void smp_send_nmi_allbutself(void)
+ {
 -	cpumask_t mask = cpu_online_map;
 -	cpu_clear(safe_smp_processor_id(), mask);
 -	if (!cpus_empty(mask))
 -		send_IPI_mask(mask, NMI_VECTOR);
++	send_IPI_allbutself(NMI_VECTOR);
+ }
+ 
+ static struct notifier_block crash_nmi_nb = {
+ 	.notifier_call = crash_nmi_callback,
+ };
+ 
+ /* Halt all other CPUs, calling the specified function on each of them
+  *
+  * This function can be used to halt all other CPUs on crash
+  * or emergency reboot time. The function passed as parameter
+  * will be called inside a NMI handler on all CPUs.
+  */
+ void nmi_shootdown_cpus(nmi_shootdown_cb callback)
+ {
+ 	unsigned long msecs;
+ 	local_irq_disable();
+ 
+ 	/* Make a note of crashing cpu. Will be used in NMI callback.*/
+ 	crashing_cpu = safe_smp_processor_id();
+ 
+ 	shootdown_callback = callback;
+ 
+ 	atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
+ 	/* Would it be better to replace the trap vector here? */
+ 	if (register_die_notifier(&crash_nmi_nb))
+ 		return;		/* return what? */
+ 	/* 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 */
+ }
+ #else /* !CONFIG_SMP */
+ void nmi_shootdown_cpus(nmi_shootdown_cb callback)
+ {
+ 	/* No other CPUs to shoot down */
+ }
+ #endif