Subject: Re: [PATCH v2] PowerPC: kernel: compiling issue, make additional room in exception vector area

From: Mike Qiu <[email-masked]>
Date: Fri, 26 Apr 2013 10:03:02 +0800

于 2013/4/26 9:36, Chen Gang 写道:
> On 2013年04月26日 09:18, Chen Gang wrote:
>> On 2013年04月26日 09:06, Chen Gang wrote:
>>>> CFAR is the Come From Register.  It saves the location of the last
>>>>> branch and is hence overwritten by any branch.
>>>>>
>>> Do we process it just like others done (e.g. 0x300, 0xe00, 0xe20 ...) ?
>>> 	. = 0x900
>>> 	.globl decrementer_pSeries
>>> decrementer_pSeries:
>>>  	HMT_MEDIUM_PPR_DISCARD
>>> 	SET_SCRATCH0(r13)
>>> 	b decrementer_pSeries_0
>>>
>>> 	...
>>>
>>>
> Oh, it seems EXCEPTION_PROLOG_1 will save the regesters which related
> with CFAR, so I think need move EXCEPTION_PROLOG_1 to near 0x900.

I will try your diff V2, to see if the machine can boot up
> ---------------------------------diff v2 begin-----------------------------
>
> diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
> index e789ee7..f0489c4 100644
> --- a/arch/powerpc/kernel/exceptions-64s.S
> +++ b/arch/powerpc/kernel/exceptions-64s.S
> @@ -254,7 +254,15 @@ hardware_interrupt_hv:
>  	STD_EXCEPTION_PSERIES(0x800, 0x800, fp_unavailable)
>  	KVM_HANDLER_PR(PACA_EXGEN, EXC_STD, 0x800)
>
> -	MASKABLE_EXCEPTION_PSERIES(0x900, 0x900, decrementer)
> +	. = 0x900
> +	.globl decrementer_pSeries
> +decrementer_pSeries:
> +	HMT_MEDIUM_PPR_DISCARD
> +	SET_SCRATCH0(r13)		/* save r13 */
> +	EXCEPTION_PROLOG_0(PACA_EXGEN)
> +	EXCEPTION_PROLOG_1(PACA_EXGEN, SOFTEN_TEST_PR, 0x900)
> +	b	decrementer_pSeries_0
> +
>  	STD_EXCEPTION_HV(0x980, 0x982, hdecrementer)
>
>  	MASKABLE_EXCEPTION_PSERIES(0xa00, 0xa00, doorbell_super)
> @@ -536,6 +544,11 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_206)
>  #endif
>
>  	.align	7
> +	/* moved from 0x900 */
> +decrementer_pSeries_0:
> +	EXCEPTION_PROLOG_PSERIES_1(decrementer_common, EXC_STD)
> +
> +	.align	7
>  	/* moved from 0xe00 */
>  	STD_EXCEPTION_HV_OOL(0xe02, h_data_storage)
>  	KVM_HANDLER_SKIP(PACA_EXGEN, EXC_HV, 0xe02)
>
>
> ---------------------------------diff v2 end-------------------------------
>
>
>> Such as the fix below, is it OK (just like 0x300 or 0x200 has done) ?
>>
>> Please check, thanks.
>>
>> ---------------------------diff begin-------------------------------------
>>
>> diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
>> index e789ee7..a0a5ff2 100644
>> --- a/arch/powerpc/kernel/exceptions-64s.S
>> +++ b/arch/powerpc/kernel/exceptions-64s.S
>> @@ -254,7 +254,14 @@ hardware_interrupt_hv:
>>  	STD_EXCEPTION_PSERIES(0x800, 0x800, fp_unavailable)
>>  	KVM_HANDLER_PR(PACA_EXGEN, EXC_STD, 0x800)
>>  
>> -	MASKABLE_EXCEPTION_PSERIES(0x900, 0x900, decrementer)
>> +	. = 0x900
>> +	.globl decrementer_pSeries
>> +decrementer_pSeries:
>> +	HMT_MEDIUM_PPR_DISCARD
>> +	SET_SCRATCH0(r13)		/* save r13 */
>> +	EXCEPTION_PROLOG_0(PACA_EXGEN)
>> +	b	decrementer_pSeries_0
>> +
>>  	STD_EXCEPTION_HV(0x980, 0x982, hdecrementer)
>>  
>>  	MASKABLE_EXCEPTION_PSERIES(0xa00, 0xa00, doorbell_super)
>> @@ -536,6 +543,12 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_206)
>>  #endif
>>  
>>  	.align	7
>> +	/* moved from 0x900 */
>> +decrementer_pSeries_0:
>> +	EXCEPTION_PROLOG_1(PACA_EXGEN, SOFTEN_TEST_PR, 0x900)
>> +	EXCEPTION_PROLOG_PSERIES_1(decrementer_common, EXC_STD)
>> +
>> +	.align	7
>>  	/* moved from 0xe00 */
>>  	STD_EXCEPTION_HV_OOL(0xe02, h_data_storage)
>>  	KVM_HANDLER_SKIP(PACA_EXGEN, EXC_HV, 0xe02)
>>
>> ---------------------------diff end---------------------------------------
>>
>