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Commit e2f7f737 authored by Matt Evans's avatar Matt Evans Committed by Benjamin Herrenschmidt
Browse files

powerpc/kexec: Add to and tidy debug/comments in machine_kexec64.c 



Tidies some typos, KERN_INFO-ise an info msg, and add a debug msg showing
when the final sequence starts.

Also adds a comment to kexec_prepare_cpus_wait() to make note of a possible
problem; the need for kexec to deal with CPUs that failed to originally start
up.

Signed-off-by: default avatarMatt Evans <matt@ozlabs.org>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 2c48a7d6

arch/powerpc/kernel/machine_kexec_64.c

+24 −5
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
#include <linux/thread_info.h>

#include <linux/init_task.h>

#include <linux/errno.h>

#include <linux/kernel.h>



#include <asm/page.h>

#include <asm/current.h>
@@ -184,7 +185,20 @@ static void kexec_prepare_cpus_wait(int wait_state) 


	hw_breakpoint_disable();

	my_cpu = get_cpu();

	/* Make sure each CPU has atleast made it to the state we need */

	/* Make sure each CPU has at least made it to the state we need.

	 *

	 * FIXME: There is a (slim) chance of a problem if not all of the CPUs

	 * are correctly onlined.  If somehow we start a CPU on boot with RTAS

	 * start-cpu, but somehow that CPU doesn't write callin_cpu_map[] in

	 * time, the boot CPU will timeout.  If it does eventually execute

	 * stuff, the secondary will start up (paca[].cpu_start was written) and

	 * get into a peculiar state.  If the platform supports

	 * smp_ops->take_timebase(), the secondary CPU will probably be spinning

	 * in there.  If not (i.e. pseries), the secondary will continue on and

	 * try to online itself/idle/etc. If it survives that, we need to find

	 * these possible-but-not-online-but-should-be CPUs and chaperone them

	 * into kexec_smp_wait().

	 */

	for_each_online_cpu(i) {

		if (i == my_cpu)

			continue;
@@ -192,8 +206,8 @@ static void kexec_prepare_cpus_wait(int wait_state) 
		while (paca[i].kexec_state < wait_state) {

			barrier();

			if (i != notified) {

				printk( "kexec: waiting for cpu %d (physical"

						" %d) to enter %i state\n",

				printk(KERN_INFO "kexec: waiting for cpu %d "

				       "(physical %d) to enter %i state\n",

				       i, paca[i].hw_cpu_id, wait_state);

				notified = i;

			}
@@ -218,7 +232,10 @@ static void kexec_prepare_cpus(void) 
	if (ppc_md.kexec_cpu_down)

		ppc_md.kexec_cpu_down(0, 0);



	/* Before removing MMU mapings make sure all CPUs have entered real mode */

	/*

	 * Before removing MMU mappings make sure all CPUs have entered real

	 * mode:

	 */

	kexec_prepare_cpus_wait(KEXEC_STATE_REAL_MODE);



	put_cpu();
@@ -287,6 +304,8 @@ void default_machine_kexec(struct kimage *image) 
	if (crashing_cpu == -1)

		kexec_prepare_cpus();



	pr_debug("kexec: Starting switchover sequence.\n");



	/* switch to a staticly allocated stack.  Based on irq stack code.

	 * XXX: the task struct will likely be invalid once we do the copy!

	 */