| Message ID | 1407749048-18909-1-git-send-email-mark.rutland@arm.com |
|---|---|
| State | Accepted |
| Commit | 85868313177700d20644263a782351262d2aff84 |
| Headers | show |
On the assumption these are fine I've dropped both into the patch system (as 8128/1 and 8129/1 respectively). Thanks, Mark. -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/arm/mm/abort-ev6.S b/arch/arm/mm/abort-ev6.S index 3815a82..8c48c5c 100644 --- a/arch/arm/mm/abort-ev6.S +++ b/arch/arm/mm/abort-ev6.S @@ -17,12 +17,6 @@ */ .align 5 ENTRY(v6_early_abort) -#ifdef CONFIG_CPU_V6 - sub r1, sp, #4 @ Get unused stack location - strex r0, r1, [r1] @ Clear the exclusive monitor -#elif defined(CONFIG_CPU_32v6K) - clrex -#endif mrc p15, 0, r1, c5, c0, 0 @ get FSR mrc p15, 0, r0, c6, c0, 0 @ get FAR /* diff --git a/arch/arm/mm/abort-ev7.S b/arch/arm/mm/abort-ev7.S index 7033752..4812ad0 100644 --- a/arch/arm/mm/abort-ev7.S +++ b/arch/arm/mm/abort-ev7.S @@ -13,12 +13,6 @@ */ .align 5 ENTRY(v7_early_abort) - /* - * The effect of data aborts on on the exclusive access monitor are - * UNPREDICTABLE. Do a CLREX to clear the state - */ - clrex - mrc p15, 0, r1, c5, c0, 0 @ get FSR mrc p15, 0, r0, c6, c0, 0 @ get FAR
The ARMv6 and ARMv7 early abort handlers clear the exclusive monitors upon entry to the kernel, but this is redundant: - We clear the monitors on every exception return since commit 200b812d0084 ("Clear the exclusive monitor when returning from an exception"), so this is not necessary to ensure the monitors are cleared before returning from a fault handler. - Any dummy STREX will target a temporary scratch area in memory, and may succeed or fail without corrupting useful data. Its status value will not be used. - Any other STREX in the kernel must be preceded by an LDREX, which will initialise the monitors consistently and will not depend on the earlier state of the monitors. Therefore we have no reason to care about the initial state of the exclusive monitors when a data abort is taken, and clearing the monitors prior to exception return (as we already do) is sufficient. This patch removes the redundant clearing of the exclusive monitors from the early abort handlers. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Cc: stable@vger.kernel.org --- arch/arm/mm/abort-ev6.S | 6 ------ arch/arm/mm/abort-ev7.S | 6 ------ 2 files changed, 12 deletions(-)