Re: [PATCH 07/56] microblaze_v2: Signal support

[Michal Simek]

I hope that conclusion is remove #if 0 from signal.c code.

M


> You're right.  (I think I've been staring at this too much today... :)
> 
> Steve
> 
>> -----Original Message-----
>> From: John Williams [mailto:john.williams@xxxxxxxxxxxxx]
>> Sent: Monday, May 05, 2008 5:26 PM
>> To: Stephen Neuendorffer
>> Cc: monstr@xxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; arnd@xxxxxxxx;
> linux-arch@xxxxxxxxxxxxxxx; John
>> Linn; matthew@xxxxxx; will.newton@xxxxxxxxx; drepper@xxxxxxxxxx;
> microblaze-uclinux@xxxxxxxxxxxxxx;
>> grant.likely@xxxxxxxxxxxx; Michal Simek
>> Subject: RE: [PATCH 07/56] microblaze_v2: Signal support
>>
>> On Mon, 2008-05-05 at 17:13 -0700, Stephen Neuendorffer wrote:
>>> I'm somewhat ignorant about what this code is attempting to do, but
> with
>>> some quick poking around (m68knommu, blackfin) seems to suggest that
>>> other architectures don't do this, while others (v850) have almost
>>> exactly the same code (although they are somewhat smarter and are
>>> careful not to flush the whole cache).
>>>
>>> At the very least, it seems like there is some work in this area
> needed.
>> flush_cache_sigtramp should just invalidate 8 bytes up from the base
>> address of the trampoline.  This is just the region on the process
> stack
>> where we insert a kind of call-back back.  Writing the opcodes goes
> via
>> the dcache, and so there's a vanishingly small possibility that the
> CPU
>> will get a false hit on on an icache fetch when the code is executed.
>>
>> That was what Michal's patch had when I scanned it yesterday.  It
>> certainly won't/shouldn't be invalidating the entire cache.
>>
>> Cheers,
>>
>> John
>>
>>
> 
> 
> 
> 

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