Commit e6eadc67 authored by Will Deacon's avatar Will Deacon
Browse files

ARM: suspend: use idmap_pgd instead of suspend_pgd 



The ARM CPU suspend code requires cpu_resume_mmu to be identity mapped
in order to re-enable the MMU when coming out of suspend. Currently,
this is accomplished by maintaining a suspend_pgd with the relevant
mapping put in place at init time.

This patch replaces the use of suspend_pgd with the new idmap_pgd.
cpu_resume_mmu is placed in the .idmap.text section so that it is
included in the identity map.

Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Acked-by: default avatarDave Martin <dave.martin@linaro.org>
Tested-by: default avatarLorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 8903826d

arch/arm/kernel/sleep.S

+2 −0
Original line number Diff line number Diff line
@@ -54,6 +54,7 @@ ENDPROC(cpu_suspend_abort) 
 * r0 = control register value

 */

	.align	5

	.pushsection	.idmap.text,"ax"

ENTRY(cpu_resume_mmu)

	ldr	r3, =cpu_resume_after_mmu

	mcr	p15, 0, r0, c1, c0, 0	@ turn on MMU, I-cache, etc
@@ -62,6 +63,7 @@ ENTRY(cpu_resume_mmu) 
	mov	r0, r0

	mov	pc, r3			@ jump to virtual address

ENDPROC(cpu_resume_mmu)

	.popsection

cpu_resume_after_mmu:

	bl	cpu_init		@ restore the und/abt/irq banked regs

	mov	r0, #0			@ return zero on success

arch/arm/kernel/suspend.c

+3 −15
Original line number Diff line number Diff line 
#include <linux/init.h>



#include <asm/idmap.h>

#include <asm/pgalloc.h>

#include <asm/pgtable.h>

#include <asm/memory.h>

#include <asm/suspend.h>

#include <asm/tlbflush.h>



static pgd_t *suspend_pgd;



extern int __cpu_suspend(unsigned long, int (*)(unsigned long));

extern void cpu_resume_mmu(void);
@@ -21,7 +20,7 @@ void __cpu_suspend_save(u32 *ptr, u32 ptrsz, u32 sp, u32 *save_ptr) 
	*save_ptr = virt_to_phys(ptr);



	/* This must correspond to the LDM in cpu_resume() assembly */

	*ptr++ = virt_to_phys(suspend_pgd);

	*ptr++ = virt_to_phys(idmap_pgd);

	*ptr++ = sp;

	*ptr++ = virt_to_phys(cpu_do_resume);
@@ -42,7 +41,7 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long)) 
	struct mm_struct *mm = current->active_mm;

	int ret;



	if (!suspend_pgd)

	if (!idmap_pgd)

		return -EINVAL;



	/*
@@ -59,14 +58,3 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long)) 


	return ret;

}
 


static int __init cpu_suspend_init(void)

{

	suspend_pgd = pgd_alloc(&init_mm);

	if (suspend_pgd) {

		unsigned long addr = virt_to_phys(cpu_resume_mmu);

		identity_mapping_add(suspend_pgd, addr, addr + SECTION_SIZE);

	}

	return suspend_pgd ? 0 : -ENOMEM;

}

core_initcall(cpu_suspend_init);

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