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SubjectRe: [PATCH] ARM: cache-v7: Disable preemption when reading CCSIDR
On 02/02/12 18:35, Nicolas Pitre wrote:
> On Thu, 2 Feb 2012, Stephen Boyd wrote:
>> On 02/02/12 17:18, Nicolas Pitre wrote:
>>> If you simply disable/restore IRQs around the critical region then you
>>> don't have to worry about __v7_setup. Plus this will allow for
>>> v7_flush_dcache_all to still be callable from atomic context.
>> Ok. Here's a patch. I still need to test it. I'll send another patch
>> series to cleanup the get_thread_info stuff (there's two of them?).
>>
>> arch/arm/mm/cache-v7.S | 6 ++++++
>> 1 files changed, 6 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch/arm/mm/cache-v7.S b/arch/arm/mm/cache-v7.S
>> index 07c4bc8..654a5fc 100644
>> --- a/arch/arm/mm/cache-v7.S
>> +++ b/arch/arm/mm/cache-v7.S
>> @@ -54,9 +54,15 @@ loop1:
>> and r1, r1, #7 @ mask of the bits for current cache only
>> cmp r1, #2 @ see what cache we have at this level
>> blt skip @ skip if no cache, or just i-cache
>> +#ifdef CONFIG_PREEMPT
>> + save_and_disable_irqs r9 @ make cssr&csidr read atomic
>> +#endif
>> mcr p15, 2, r10, c0, c0, 0 @ select current cache level in cssr
>> isb @ isb to sych the new cssr&csidr
>> mrc p15, 1, r1, c0, c0, 0 @ read the new csidr
>> +#ifdef CONFIG_PREEMPT
>> + restore_irqs r9
>> +#endif
> I'd suggest using restore_irqs_notrace instead. The IRQ-off period is
> so small that there is no point tracing it.

Thanks. I'll make sure to do that before uploading to the patch tracker.

--
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.



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