Commit cafc0eab authored by Ard Biesheuvel's avatar Ard Biesheuvel
Browse files

ARM: v7m: enable support for IRQ stacks 



Enable support for IRQ stacks on !MMU, and add the code to the IRQ entry
path to switch to the IRQ stack if not running from it already.

Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
Tested-by: default avatarMarc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
parent 9c46929e

arch/arm/Kconfig

+0 −1
Original line number Diff line number Diff line
@@ -1158,7 +1158,6 @@ config CURRENT_POINTER_IN_TPIDRURO 


config IRQSTACKS

	def_bool y

	depends on MMU

	select HAVE_IRQ_EXIT_ON_IRQ_STACK

	select HAVE_SOFTIRQ_ON_OWN_STACK

arch/arm/kernel/entry-v7m.S

+15 −2
Original line number Diff line number Diff line
@@ -40,11 +40,24 @@ __irq_entry: 
	@ Invoke the IRQ handler

	@

	mov	r0, sp

	stmdb	sp!, {lr}

	ldr_this_cpu sp, irq_stack_ptr, r1, r2



	@

	@ If we took the interrupt while running in the kernel, we may already

	@ be using the IRQ stack, so revert to the original value in that case.

	@

	subs	r2, sp, r0		@ SP above bottom of IRQ stack?

	rsbscs	r2, r2, #THREAD_SIZE	@ ... and below the top?

	movcs	sp, r0



	push	{r0, lr}		@ preserve LR and original SP



	@ routine called with r0 = struct pt_regs *

	bl	generic_handle_arch_irq



	pop	{lr}

	pop	{r0, lr}

	mov	sp, r0



	@

	@ Check for any pending work if returning to user

	@