[PATCH] ARM: cache-v7: Disable preemption when reading CCSIDR
Sergei Shtylyov
sshtylyov at ru.mvista.com
Fri Feb 3 06:15:45 EST 2012
Hello.
On 03-02-2012 7:04, 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.
> Might be worth flagging this for the stable kernels as well
> (CC: stable at kernel.org).
The new address is stable at vger.kernel.org as Greg KH wrote.
WBR, Sergei
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