Commit 11800571 authored by Sourabh Jain's avatar Sourabh Jain Committed by Michael Ellerman
Browse files

crash: forward memory_notify arg to arch crash hotplug handler 



In the event of memory hotplug or online/offline events, the crash
memory hotplug notifier `crash_memhp_notifier()` receives a
`memory_notify` object but doesn't forward that object to the
generic and architecture-specific crash hotplug handler.

The `memory_notify` object contains the starting PFN (Page Frame Number)
and the number of pages in the hot-removed memory. This information is
necessary for architectures like PowerPC to update/recreate the kdump
image, specifically `elfcorehdr`.

So update the function signature of `crash_handle_hotplug_event()` and
`arch_crash_handle_hotplug_event()` to accept the `memory_notify` object
as an argument from crash memory hotplug notifier.

Since no such object is available in the case of CPU hotplug event, the
crash CPU hotplug notifier `crash_cpuhp_online()` passes NULL to the
crash hotplug handler.

Signed-off-by: default avatarSourabh Jain <sourabhjain@linux.ibm.com>
Acked-by: default avatarBaoquan He <bhe@redhat.com>
Acked-by: default avatarHari Bathini <hbathini@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240326055413.186534-2-sourabhjain@linux.ibm.com
parent 39cd87c4

arch/x86/include/asm/kexec.h

+1 −1
Original line number Diff line number Diff line
@@ -207,7 +207,7 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image); 
extern void kdump_nmi_shootdown_cpus(void);



#ifdef CONFIG_CRASH_HOTPLUG

void arch_crash_handle_hotplug_event(struct kimage *image);

void arch_crash_handle_hotplug_event(struct kimage *image, void *arg);

#define arch_crash_handle_hotplug_event arch_crash_handle_hotplug_event



#ifdef CONFIG_HOTPLUG_CPU

arch/x86/kernel/crash.c

+3 −1
Original line number Diff line number Diff line
@@ -432,10 +432,12 @@ unsigned int arch_crash_get_elfcorehdr_size(void) 
/**

 * arch_crash_handle_hotplug_event() - Handle hotplug elfcorehdr changes

 * @image: a pointer to kexec_crash_image

 * @arg: struct memory_notify handler for memory hotplug case and

 *       NULL for CPU hotplug case.

 *

 * Prepare the new elfcorehdr and replace the existing elfcorehdr.

 */

void arch_crash_handle_hotplug_event(struct kimage *image)

void arch_crash_handle_hotplug_event(struct kimage *image, void *arg)

{

	void *elfbuf = NULL, *old_elfcorehdr;

	unsigned long nr_mem_ranges;

include/linux/crash_core.h

+1 −1
Original line number Diff line number Diff line
@@ -37,7 +37,7 @@ static inline void arch_kexec_unprotect_crashkres(void) { } 




#ifndef arch_crash_handle_hotplug_event

static inline void arch_crash_handle_hotplug_event(struct kimage *image) { }

static inline void arch_crash_handle_hotplug_event(struct kimage *image, void *arg) { }

#endif



int crash_check_update_elfcorehdr(void);

kernel/crash_core.c

+7 −7
Original line number Diff line number Diff line
@@ -534,7 +534,7 @@ int crash_check_update_elfcorehdr(void) 
 * list of segments it checks (since the elfcorehdr changes and thus

 * would require an update to purgatory itself to update the digest).

 */

static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu)

static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu, void *arg)

{

	struct kimage *image;
@@ -596,7 +596,7 @@ static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu) 
	image->hp_action = hp_action;



	/* Now invoke arch-specific update handler */

	arch_crash_handle_hotplug_event(image);

	arch_crash_handle_hotplug_event(image, arg);



	/* No longer handling a hotplug event */

	image->hp_action = KEXEC_CRASH_HP_NONE;
@@ -612,17 +612,17 @@ static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu) 
	crash_hotplug_unlock();

}



static int crash_memhp_notifier(struct notifier_block *nb, unsigned long val, void *v)

static int crash_memhp_notifier(struct notifier_block *nb, unsigned long val, void *arg)

{

	switch (val) {

	case MEM_ONLINE:

		crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_MEMORY,

			KEXEC_CRASH_HP_INVALID_CPU);

			KEXEC_CRASH_HP_INVALID_CPU, arg);

		break;



	case MEM_OFFLINE:

		crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_MEMORY,

			KEXEC_CRASH_HP_INVALID_CPU);

			KEXEC_CRASH_HP_INVALID_CPU, arg);

		break;

	}

	return NOTIFY_OK;
@@ -635,13 +635,13 @@ static struct notifier_block crash_memhp_nb = { 


static int crash_cpuhp_online(unsigned int cpu)

{

	crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_CPU, cpu);

	crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_CPU, cpu, NULL);

	return 0;

}



static int crash_cpuhp_offline(unsigned int cpu)

{

	crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_CPU, cpu);

	crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_CPU, cpu, NULL);

	return 0;

}