[PATCH 10/10] ARM: mcpm: use -st dsb option prior to sev instructions
Nicolas Pitre
nico at fluxnic.net
Fri Jun 7 00:15:44 EDT 2013
On Thu, 6 Jun 2013, Will Deacon wrote:
> In a similar manner to our spinlock implementation, mcpm uses sev to
> wake up cores waiting on a lock when the lock is unlocked. In order to
> ensure that the final write unlocking the lock is visible, a dsb
> instruction is executed immediately prior to the sev.
>
> This patch changes these dsbs to use the -st option, since we only
> require that the store unlocking the lock is made visible.
>
> Reviewed-by: Dave Martin <dave.martin at arm.com>
> Reviewed-by: Catalin Marinas <catalin.marinas at arm.com>
> Signed-off-by: Will Deacon <will.deacon at arm.com>
Acked-by: Nicolas Pitre <nico at linaro.org>
> ---
> arch/arm/common/mcpm_head.S | 2 +-
> arch/arm/common/vlock.S | 4 ++--
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm/common/mcpm_head.S b/arch/arm/common/mcpm_head.S
> index 8178705..5cdf619 100644
> --- a/arch/arm/common/mcpm_head.S
> +++ b/arch/arm/common/mcpm_head.S
> @@ -151,7 +151,7 @@ mcpm_setup_leave:
>
> mov r0, #INBOUND_NOT_COMING_UP
> strb r0, [r8, #MCPM_SYNC_CLUSTER_INBOUND]
> - dsb
> + dsb st
> sev
>
> mov r0, r11
> diff --git a/arch/arm/common/vlock.S b/arch/arm/common/vlock.S
> index ff19858..8b7df28 100644
> --- a/arch/arm/common/vlock.S
> +++ b/arch/arm/common/vlock.S
> @@ -42,7 +42,7 @@
> dmb
> mov \rscratch, #0
> strb \rscratch, [\rbase, \rcpu]
> - dsb
> + dsb st
> sev
> .endm
>
> @@ -102,7 +102,7 @@ ENTRY(vlock_unlock)
> dmb
> mov r1, #VLOCK_OWNER_NONE
> strb r1, [r0, #VLOCK_OWNER_OFFSET]
> - dsb
> + dsb st
> sev
> bx lr
> ENDPROC(vlock_unlock)
> --
> 1.8.2.2
>
>
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