Commit c9117434 authored by Huacai Chen's avatar Huacai Chen
Browse files

LoongArch: Use polling play_dead() when resuming from hibernation 



When CONFIG_RANDOM_KMALLOC_CACHES or other randomization infrastructrue
enabled, the idle_task's stack may different between the booting kernel
and target kernel. So when resuming from hibernation, an ACTION_BOOT_CPU
IPI wakeup the idle instruction in arch_cpu_idle_dead() and jump to the
interrupt handler. But since the stack pointer is changed, the interrupt
handler cannot restore correct context.

So rename the current arch_cpu_idle_dead() to idle_play_dead(), make it
as the default version of play_dead(), and the new arch_cpu_idle_dead()
call play_dead() directly. For hibernation, implement an arch-specific
hibernate_resume_nonboot_cpu_disable() to use the polling version (idle
instruction is replace by nop, and irq is disabled) of play_dead(), i.e.
poll_play_dead(), to avoid IPI handler corrupting the idle_task's stack
when resuming from hibernation.

This solution is a little similar to commit 406f992e ("x86 /
hibernate: Use hlt_play_dead() when resuming from hibernation").

Cc: stable@vger.kernel.org
Tested-by: default avatarErpeng Xu <xuerpeng@uniontech.com>
Tested-by: default avatarYuli Wang <wangyuli@uniontech.com>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent a0d3c8bc

arch/loongarch/kernel/smp.c

+46 −1
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/smp.h>

#include <linux/threads.h>

#include <linux/export.h>

#include <linux/suspend.h>

#include <linux/syscore_ops.h>

#include <linux/time.h>

#include <linux/tracepoint.h>
@@ -423,7 +424,7 @@ void loongson_cpu_die(unsigned int cpu) 
	mb();

}



void __noreturn arch_cpu_idle_dead(void)

static void __noreturn idle_play_dead(void)

{

	register uint64_t addr;

	register void (*init_fn)(void);
@@ -447,6 +448,50 @@ void __noreturn arch_cpu_idle_dead(void) 
	BUG();

}



#ifdef CONFIG_HIBERNATION

static void __noreturn poll_play_dead(void)

{

	register uint64_t addr;

	register void (*init_fn)(void);



	idle_task_exit();

	__this_cpu_write(cpu_state, CPU_DEAD);



	__smp_mb();

	do {

		__asm__ __volatile__("nop\n\t");

		addr = iocsr_read64(LOONGARCH_IOCSR_MBUF0);

	} while (addr == 0);



	init_fn = (void *)TO_CACHE(addr);

	iocsr_write32(0xffffffff, LOONGARCH_IOCSR_IPI_CLEAR);



	init_fn();

	BUG();

}

#endif



static void (*play_dead)(void) = idle_play_dead;



void __noreturn arch_cpu_idle_dead(void)

{

	play_dead();

	BUG(); /* play_dead() doesn't return */

}



#ifdef CONFIG_HIBERNATION

int hibernate_resume_nonboot_cpu_disable(void)

{

	int ret;



	play_dead = poll_play_dead;

	ret = suspend_disable_secondary_cpus();

	play_dead = idle_play_dead;



	return ret;

}

#endif



#endif



/*