Re: gdbserver on sh4

["damien.courousse.logica" <damien dot courousse at logica dot com>]

Michael Trimarchi-3 wrote:
> 
> damien.courousse.logica wrote:
>> Hello all,
>>
>>
>> Hi,
>>
>> Paul Mundt wrote:
>>   
>>> On Tue, Mar 31, 2009 at 11:02:38AM +0200, Michael Trimarchi wrote:
>>>   
>>>     
>>>> Paul Mundt wrote:
>>>>     
>>>>       
>>>>> On Tue, Mar 31, 2009 at 10:23:18AM +0200, Michael Trimarchi wrote:
>>>>>       
>>>>>         
>>>>>> The problem is kernel side and not gdb side. I send a patch to the
>>>>>> linux-sh mailing list. They save the dsp register on the stack before
>>>>>> the processor cpu register but the offset of the struct is wrong
>>>>>> calculated and if the linux kernel is compiled with the dsp option
>>>>>> the PEEKUSR return the wrong register value.
>>>>>>    
>>>>>>         
>>>>>>           
>>>>> The sanest thing really is just to throw the DSP state in to the
>>>>> thread
>>>>> struct as we do with the FPU, and kill off all of the special DSP
>>>>> state
>>>>> handling we have today. It costs us a thread flag to do lazy context
>>>>>  
>>>>>       
>>>>>         
>>>> I just send a patch that put the dsp state in the thread struct
>>>>     
>>>>       
>>> You sent a patch that cached the enable/disable state in the thread
>>> struct, not the register state. ;-) 
>>>
>>>   
>>>     
>>>>> switching, but it's worth it to get that crap out of the regular
>>>>> register
>>>>> save/restore paths, which is just way too fragile, and has not seen
>>>>> any
>>>>> real maintenance since SH3-DSP.
>>>>>  
>>>>>       
>>>>>         
>>>> So move the save/restore part of the dsp in private data of task and do
>>>> like
>>>> mips?
>>>>     
>>>>       
>>> Yes.
>>>   
>>>     
>> Ok, I will try to provide a new patch to move out the dsp save/restore 
>> part from the
>> stack and move all on the thread privata data.
>>
>>
>>
>> I am currently facing the same problem that is described in this thread,
>> also on sh4.
>> Michael did you provide a kernel patch to fix this? If possible, how
>> could I
>> help you?
>>   
> Hi, I just move the dsp register over the stack and I try it. What 
> kernel version do you use?
> 
> Michael
> 
> 


Hi Michael,

I use a kernel source tree modified by STmicroelectronics :
linux-sh4-STAPI_2.6.23.17_stm23_A16 - it is based on the kernel 2.6.23.

Damien

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