Re: [PATCH] ARM: mm: avoid attempting to flush the gate_vma with VIVT caches

[Gilles Chanteperdrix <gilles.chanteperdrix@xxxxxxxxxxx>]

On 07/21/2012 04:40 PM, Gilles Chanteperdrix wrote:
> On 07/21/2012 04:35 PM, Will Deacon wrote:
>> Hi Gilles,
>>
>> On Sat, Jul 21, 2012 at 02:18:35PM +0100, Gilles Chanteperdrix wrote:
>>> On 07/20/2012 10:41 PM, Gilles Chanteperdrix wrote:
>>>> Being 0 or 1 whether we want to flush the vector page (I believe we do
>>>> not want to flush it, but am not sure).
>>>
>>> Actually, I believe we want to flush the vector page, at least on
>>> systems with VIVT cache: on systems with VIVT cache, the vector page is
>>> writeable in kernel mode, so may have been modified, and the address
>>> used by elf_core_dump is not the vectors address, but the address in the
>>> kernel direct-mapped RAM region where the vector page was allocated, so
>>> there is a cache aliasing issue.
>>
>> It may be writable, but we never actually write to it after it has been
>> initialised so there's no need to worry about caching issues (the cache is
>> flushed in devicemaps_init).
> 
> Except if CONFIG_TLS_REG_EMUL is enabled

is disabled I mean.

-- 
                                                                Gilles.

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