Re: [PATCH v6 07/24] arm64: Make PMR part of task context
From: Catalin Marinas
Date: Tue Dec 04 2018 - 12:09:15 EST
On Mon, Nov 12, 2018 at 11:56:58AM +0000, Julien Thierry wrote:
> diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
> index 039144e..eb8120e 100644
> --- a/arch/arm64/kernel/entry.S
> +++ b/arch/arm64/kernel/entry.S
> @@ -249,6 +249,12 @@ alternative_else_nop_endif
> msr sp_el0, tsk
> .endif
>
> + /* Save pmr */
> +alternative_if ARM64_HAS_IRQ_PRIO_MASKING
> + mrs_s x20, SYS_ICC_PMR_EL1
> + str x20, [sp, #S_PMR_SAVE]
> +alternative_else_nop_endif
> +
> /*
> * Registers that may be useful after this macro is invoked:
> *
> @@ -269,6 +275,13 @@ alternative_else_nop_endif
> /* No need to restore UAO, it will be restored from SPSR_EL1 */
> .endif
>
> + /* Restore pmr */
> +alternative_if ARM64_HAS_IRQ_PRIO_MASKING
> + ldr x20, [sp, #S_PMR_SAVE]
> + msr_s SYS_ICC_PMR_EL1, x20
> + dsb sy
> +alternative_else_nop_endif
What's this DSB for? If it's needed, please add a comment.
I would have expected an ISB (or none at all as we are going to return
from an exception).
--
Catalin