Commit 8b806b82 authored by Ard Biesheuvel's avatar Ard Biesheuvel
Browse files

ARM: mm: switch to swapper_pg_dir early for vmap'ed stack 



When onlining a CPU, switch to swapper_pg_dir as soon as possible so
that it is guaranteed that the vmap'ed stack is mapped before it is
used.

Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
parent 5fe41793

arch/arm/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -128,7 +128,7 @@ config ARM 
	select RTC_LIB

	select SYS_SUPPORTS_APM_EMULATION

	select THREAD_INFO_IN_TASK

	select HAVE_ARCH_VMAP_STACK if MMU && (!LD_IS_LLD || LLD_VERSION >= 140000) && !PM_SLEEP_SMP

	select HAVE_ARCH_VMAP_STACK if MMU && (!LD_IS_LLD || LLD_VERSION >= 140000)

	select TRACE_IRQFLAGS_SUPPORT if !CPU_V7M

	# Above selects are sorted alphabetically; please add new ones

	# according to that.  Thanks.

arch/arm/kernel/head.S

+7 −0
Original line number Diff line number Diff line
@@ -424,6 +424,13 @@ ENDPROC(secondary_startup) 
ENDPROC(secondary_startup_arm)



ENTRY(__secondary_switched)

#if defined(CONFIG_VMAP_STACK) && !defined(CONFIG_ARM_LPAE)

	@ Before using the vmap'ed stack, we have to switch to swapper_pg_dir

	@ as the ID map does not cover the vmalloc region.

	mrc	p15, 0, ip, c2, c0, 1	@ read TTBR1

	mcr	p15, 0, ip, c2, c0, 0	@ set TTBR0

	instr_sync

#endif

	adr_l	r7, secondary_data + 12		@ get secondary_data.stack

	ldr	sp, [r7]

	ldr	r0, [r7, #4]			@ get secondary_data.task

arch/arm/kernel/sleep.S

+7 −0
Original line number Diff line number Diff line
@@ -119,6 +119,13 @@ ENTRY(cpu_resume_mmu) 
ENDPROC(cpu_resume_mmu)

	.popsection

cpu_resume_after_mmu:

#if defined(CONFIG_VMAP_STACK) && !defined(CONFIG_ARM_LPAE)

	@ Before using the vmap'ed stack, we have to switch to swapper_pg_dir

	@ as the ID map does not cover the vmalloc region.

	mrc	p15, 0, ip, c2, c0, 1	@ read TTBR1

	mcr	p15, 0, ip, c2, c0, 0	@ set TTBR0

	instr_sync

#endif

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

	mov	r0, #0			@ return zero on success

	ldmfd	sp!, {r4 - r11, pc}