Commit 1aede681 authored by Russell King's avatar Russell King
Browse files

ARM: pm: no need to save/restore context ID register 



There is no need to save and restore the context ID register on ARMv6
and ARMv7 with a temporary page table as we write the context ID
register when we switch back to the real page tables for the thread.

Moreover, the temporary page tables do not contain any non-global
mappings, so the context ID value should not be used.  To be safe,
initialize the register to a reserved context ID value.

Tested-by: default avatarSantosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: default avatarShawn Guo <shawn.guo@linaro.org>
Tested-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent de8e71ca

arch/arm/mm/proc-v6.S

+16 −17
Original line number Diff line number Diff line
@@ -128,19 +128,18 @@ ENTRY(cpu_v6_set_pte_ext) 


/* Suspend/resume support: taken from arch/arm/mach-s3c64xx/sleep.S */

.globl	cpu_v6_suspend_size

.equ	cpu_v6_suspend_size, 4 * 7

.equ	cpu_v6_suspend_size, 4 * 6

#ifdef CONFIG_PM_SLEEP

ENTRY(cpu_v6_do_suspend)

	stmfd	sp!, {r4 - r10, lr}

	stmfd	sp!, {r4 - r9, lr}

	mrc	p15, 0, r4, c13, c0, 0	@ FCSE/PID

	mrc	p15, 0, r5, c13, c0, 1	@ Context ID

	mrc	p15, 0, r6, c3, c0, 0	@ Domain ID

	mrc	p15, 0, r7, c2, c0, 1	@ Translation table base 1

	mrc	p15, 0, r8, c1, c0, 1	@ auxiliary control register

	mrc	p15, 0, r9, c1, c0, 2	@ co-processor access control

	mrc	p15, 0, r10, c1, c0, 0	@ control register

	stmia	r0, {r4 - r10}

	ldmfd	sp!, {r4- r10, pc}

	mrc	p15, 0, r5, c3, c0, 0	@ Domain ID

	mrc	p15, 0, r6, c2, c0, 1	@ Translation table base 1

	mrc	p15, 0, r7, c1, c0, 1	@ auxiliary control register

	mrc	p15, 0, r8, c1, c0, 2	@ co-processor access control

	mrc	p15, 0, r9, c1, c0, 0	@ control register

	stmia	r0, {r4 - r9}

	ldmfd	sp!, {r4- r9, pc}

ENDPROC(cpu_v6_do_suspend)



ENTRY(cpu_v6_do_resume)
@@ -149,19 +148,19 @@ ENTRY(cpu_v6_do_resume) 
	mcr	p15, 0, ip, c7, c5, 0	@ invalidate I cache

	mcr	p15, 0, ip, c7, c15, 0	@ clean+invalidate cache

	mcr	p15, 0, ip, c7, c10, 4	@ drain write buffer

	ldmia	r0, {r4 - r10}

	mcr	p15, 0, ip, c13, c0, 1	@ set reserved context ID

	ldmia	r0, {r4 - r9}

	mcr	p15, 0, r4, c13, c0, 0	@ FCSE/PID

	mcr	p15, 0, r5, c13, c0, 1	@ Context ID

	mcr	p15, 0, r6, c3, c0, 0	@ Domain ID

	mcr	p15, 0, r5, c3, c0, 0	@ Domain ID

	ALT_SMP(orr	r1, r1, #TTB_FLAGS_SMP)

	ALT_UP(orr	r1, r1, #TTB_FLAGS_UP)

	mcr	p15, 0, r1, c2, c0, 0	@ Translation table base 0

	mcr	p15, 0, r7, c2, c0, 1	@ Translation table base 1

	mcr	p15, 0, r8, c1, c0, 1	@ auxiliary control register

	mcr	p15, 0, r9, c1, c0, 2	@ co-processor access control

	mcr	p15, 0, r6, c2, c0, 1	@ Translation table base 1

	mcr	p15, 0, r7, c1, c0, 1	@ auxiliary control register

	mcr	p15, 0, r8, c1, c0, 2	@ co-processor access control

	mcr	p15, 0, ip, c2, c0, 2	@ TTB control register

	mcr	p15, 0, ip, c7, c5, 4	@ ISB

	mov	r0, r10			@ control register

	mov	r0, r9			@ control register

	b	cpu_resume_mmu

ENDPROC(cpu_v6_do_resume)

#endif

arch/arm/mm/proc-v7.S

+6 −7
Original line number Diff line number Diff line
@@ -217,14 +217,13 @@ ENDPROC(cpu_v7_set_pte_ext) 


/* Suspend/resume support: derived from arch/arm/mach-s5pv210/sleep.S */

.globl	cpu_v7_suspend_size

.equ	cpu_v7_suspend_size, 4 * 8

.equ	cpu_v7_suspend_size, 4 * 7

#ifdef CONFIG_PM_SLEEP

ENTRY(cpu_v7_do_suspend)

	stmfd	sp!, {r4 - r10, lr}

	mrc	p15, 0, r4, c13, c0, 0	@ FCSE/PID

	mrc	p15, 0, r5, c13, c0, 1	@ Context ID

	mrc	p15, 0, r6, c13, c0, 3	@ User r/o thread ID

	stmia	r0!, {r4 - r6}

	mrc	p15, 0, r5, c13, c0, 3	@ User r/o thread ID

	stmia	r0!, {r4 - r5}

	mrc	p15, 0, r6, c3, c0, 0	@ Domain ID

	mrc	p15, 0, r7, c2, c0, 1	@ TTB 1

	mrc	p15, 0, r8, c1, c0, 0	@ Control register
@@ -238,10 +237,10 @@ ENTRY(cpu_v7_do_resume) 
	mov	ip, #0

	mcr	p15, 0, ip, c8, c7, 0	@ invalidate TLBs

	mcr	p15, 0, ip, c7, c5, 0	@ invalidate I cache

	ldmia	r0!, {r4 - r6}

	mcr	p15, 0, ip, c13, c0, 1	@ set reserved context ID

	ldmia	r0!, {r4 - r5}

	mcr	p15, 0, r4, c13, c0, 0	@ FCSE/PID

	mcr	p15, 0, r5, c13, c0, 1	@ Context ID

	mcr	p15, 0, r6, c13, c0, 3	@ User r/o thread ID

	mcr	p15, 0, r5, c13, c0, 3	@ User r/o thread ID

	ldmia	r0, {r6 - r10}

	mcr	p15, 0, r6, c3, c0, 0	@ Domain ID

	ALT_SMP(orr	r1, r1, #TTB_FLAGS_SMP)

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