Subject: Re: [v5][PATCH 1/6] powerpc/book3e: load critical/machine/debug exception stack

From: "“tiejun.chen”" <[email-masked]>
Date: Wed, 23 Oct 2013 17:28:34 +0800

On 10/19/2013 07:55 AM, Scott Wood wrote:
> On Thu, 2013-06-20 at 18:28 +0800, Tiejun Chen wrote:
>> We always alloc critical/machine/debug check exceptions. This is
>> different from the normal exception. So we should load these exception
>> stack properly like we did for booke.
>>
>> Signed-off-by: Tiejun Chen <[email-masked]>
>> ---
>>   arch/powerpc/kernel/exceptions-64e.S |   49 +++++++++++++++++++++++++++++++---
>>   1 file changed, 46 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S
>> index 4b23119..4d8e57f 100644
>> --- a/arch/powerpc/kernel/exceptions-64e.S
>> +++ b/arch/powerpc/kernel/exceptions-64e.S
>> @@ -36,6 +36,37 @@
>>    */
>>   #define	SPECIAL_EXC_FRAME_SIZE	INT_FRAME_SIZE
>>
>> +/* only on book3e */
>> +#define DBG_STACK_BASE		dbgirq_ctx
>> +#define MC_STACK_BASE		mcheckirq_ctx
>> +#define CRIT_STACK_BASE		critirq_ctx
>> +
>> +#ifdef CONFIG_RELOCATABLE
>> +#define LOAD_STACK_BASE(reg, level)			\
>> +	tovirt(r2,r2);					\
>> +	LOAD_REG_ADDR(reg, level##_STACK_BASE);
>
> Where does r2 come from here, where does it get used, and why do we need
> tovirt() on book3e?
>

As I remember this should be covered when we boot that capture kernel in 
kexec/kdump case.

Now this is also gone away after move forward the c code.

Thanks,

Tiejun