[PATCH 1/2] Fix the I-cache invalidation on ARMv6 and later CPUs

[Minchan Kim]

Sorry for the noise by old mailing list address.
Fix and resend.
Thanks.

On Tue, Nov 9, 2010 at 2:03 PM, Minchan Kim <minchan.kim at gmail.com> wrote:
> It's too old story.
> Sorry for the late question.
>
> On Fri, Jun 6, 2008 at 8:46 PM, Catalin Marinas <catalin.marinas at arm.com> wrote:
>> This patch adds the I-cache invalidation in update_mmu_cache if the
>> corresponding vma is marked as executable. It also invalidates the
>> I-cache if a thread migrates to a CPU it never ran on.
>
> The description says just two place in update_mmu_cache and CPU
> migration point.
> I agree on it.
>
>>
>> Signed-off-by: Catalin Marinas <catalin.marinas at arm.com>
>> ---
>>
>>  arch/arm/mm/fault-armv.c      |    4 ++++
>>  arch/arm/mm/flush.c           |    2 ++
>>  include/asm-arm/cacheflush.h  |    7 +++++++
>>  include/asm-arm/mmu_context.h |    5 +++++
>>  4 files changed, 18 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch/arm/mm/fault-armv.c b/arch/arm/mm/fault-armv.c
>> index 44558d5..fbfa260 100644
>> --- a/arch/arm/mm/fault-armv.c
>> +++ b/arch/arm/mm/fault-armv.c
>> @@ -144,13 +144,17 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
>>        page = pfn_to_page(pfn);
>>        mapping = page_mapping(page);
>>        if (mapping) {
>> +#ifndef CONFIG_SMP
>>                int dirty = test_and_clear_bit(PG_dcache_dirty, &page->flags);
>>
>>                if (dirty)
>>                        __flush_dcache_page(mapping, page);
>> +#endif
>>
>>                if (cache_is_vivt())
>>                        make_coherent(mapping, vma, addr, pfn);
>> +               else if (vma->vm_flags & VM_EXEC)
>> +                       __flush_icache_all();
>>        }
>>  }
>>
>> diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c
>> index 9df507d..029ee65 100644
>> --- a/arch/arm/mm/flush.c
>> +++ b/arch/arm/mm/flush.c
>> @@ -199,6 +199,8 @@ void flush_dcache_page(struct page *page)
>>                __flush_dcache_page(mapping, page);
>>                if (mapping && cache_is_vivt())
>>                        __flush_dcache_aliases(mapping, page);
>> +               else if (mapping)
>> +                       __flush_icache_all();
>>        }
>
> Here, let me ask questions.
> 1. Why do we flush icache in  flush_dcache_page? Does it really needed?
> 2. If we really need it, should we even flush it in !VM_EXEC?
>
> It was rather changed in 2.6.27-rc series. But still it flushes icache
> in flush_dcache_page regardless of executable permission.
>
> --
> Kind regards,
> Minchan Kim
>



-- 
Kind regards,
Minchan Kim