[PATCH v2] arm: Hook up SYNC_CORE functionality for sys_membarrier()

[mathieu.desnoyers@efficios.com (Mathieu Desnoyers)]

----- On Jun 26, 2018, at 5:42 AM, Will Deacon will.deacon at arm.com wrote:

> Exception return implies context synchronization, so we can hook up the
> SYNC_CORE option to sys_membarrier() simply by selecting the Kconfig option,
> just like we've done for arm64 already.
> 
> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> Cc: Orion Hodson <oth@google.com>
> Signed-off-by: Will Deacon <will.deacon@arm.com>

Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Thanks!

Mathieu

> ---
> 
> v1 -> v2: Update arch-support.txt
> 
> .../features/sched/membarrier-sync-core/arch-support.txt          | 8 ++++----
> arch/arm/Kconfig                                                  | 1 +
> 2 files changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/Documentation/features/sched/membarrier-sync-core/arch-support.txt
> b/Documentation/features/sched/membarrier-sync-core/arch-support.txt
> index dbdf62907703..c7858dd1ea8f 100644
> --- a/Documentation/features/sched/membarrier-sync-core/arch-support.txt
> +++ b/Documentation/features/sched/membarrier-sync-core/arch-support.txt
> @@ -5,10 +5,10 @@
> #
> # Architecture requirements
> #
> -# * arm64
> +# * arm/arm64
> #
> -# Rely on eret context synchronization when returning from IPI handler, and
> -# when returning to user-space.
> +# Rely on implicit context synchronization as a result of exception return
> +# when returning from IPI handler, and when returning to user-space.
> #
> # * x86
> #
> @@ -31,7 +31,7 @@
>     -----------------------
>     |       alpha: | TODO |
>     |         arc: | TODO |
> -    |         arm: | TODO |
> +    |         arm: |  ok  |
>     |       arm64: |  ok  |
>     |         c6x: | TODO |
>     |       h8300: | TODO |
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 54eeb8d00bc6..b0ac18547370 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -9,6 +9,7 @@ config ARM
> 	select ARCH_HAS_ELF_RANDOMIZE
> 	select ARCH_HAS_FORTIFY_SOURCE
> 	select ARCH_HAS_KCOV
> +	select ARCH_HAS_MEMBARRIER_SYNC_CORE
> 	select ARCH_HAS_PTE_SPECIAL if ARM_LPAE
> 	select ARCH_HAS_PHYS_TO_DMA
> 	select ARCH_HAS_SET_MEMORY
> --
> 2.1.4

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com