[PATCH] ARM: V7M: Preserve registers across switch from Thread to Handler mode
Vladimir Murzin
vladimir.murzin at arm.com
Tue Apr 18 08:54:11 EDT 2017
On 30/03/17 09:09, Vladimir Murzin wrote:
> According to ARMv7 ARM, when exception is taken content of r0-r3, r12
> is unknown (see ExceptionTaken() pseudocode). Even though existent
> implementations keep these register unchanged, preserve them to be in
> line with architecture.
>
> Reported-by: Dobromir Stefanov <dobromir.stefanov at arm.com>
> Signed-off-by: Vladimir Murzin <vladimir.murzin at arm.com>
> ---
> arch/arm/mm/proc-v7m.S | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/arm/mm/proc-v7m.S b/arch/arm/mm/proc-v7m.S
> index 5049777..47a5acc 100644
> --- a/arch/arm/mm/proc-v7m.S
> +++ b/arch/arm/mm/proc-v7m.S
> @@ -135,9 +135,11 @@ __v7m_setup_cont:
> dsb
> mov r6, lr @ save LR
> ldr sp, =init_thread_union + THREAD_START_SP
> + stmia sp, {r0-r3, r12}
> cpsie i
> svc #0
> 1: cpsid i
> + ldmia sp, {r0-r3, r12}
> str r5, [r12, #11 * 4] @ restore the original SVC vector entry
> mov lr, r6 @ restore LR
>
>
Ok for patch tracker?
Vladimir
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