Subject: Re: [PATCH V10 2/4] perf/powerpc: add support for sampling intr machine state

From: Madhavan Srinivasan <[email-masked]>
Date: Mon, 25 Jan 2016 08:58:17 +0530

On Wednesday 20 January 2016 04:10 PM, Michael Ellerman wrote:
> On Mon, 2016-01-11 at 15:58 +0530, Anju T wrote:
>> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
>> index 9a7057e..c4ce60d 100644
>> --- a/arch/powerpc/Kconfig
>> +++ b/arch/powerpc/Kconfig
>> @@ -119,6 +119,7 @@ config PPC
>>  	select GENERIC_ATOMIC64 if PPC32
>>  	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
>>  	select HAVE_PERF_EVENTS
>> +	select HAVE_PERF_REGS
>>  	select HAVE_REGS_AND_STACK_ACCESS_API
>>  	select HAVE_HW_BREAKPOINT if PERF_EVENTS && PPC_BOOK3S_64
>>  	select ARCH_WANT_IPC_PARSE_VERSION
>> diff --git a/arch/powerpc/perf/perf_regs.c b/arch/powerpc/perf/perf_regs.c
>> new file mode 100644
>> index 0000000..d32581763
>> --- /dev/null
>> +++ b/arch/powerpc/perf/perf_regs.c
> ...
>> +
>> +u64 perf_reg_abi(struct task_struct *task)
>> +{
>> +	return PERF_SAMPLE_REGS_ABI_64;
> What is this value used for exactly?
>
> It seems like on 32-bit kernels we should be returning PERF_SAMPLE_REGS_ABI_32.

Yes. you are right. But even in 64bit kernel, based on the application
we need to return 32 to 64 abi. Damn my bad. missed 32bit part
all together.

Maddy
>
>> +}
>> +
>> +void perf_get_regs_user(struct perf_regs *regs_user,
>> +			struct pt_regs *regs,
>> +			struct pt_regs *regs_user_copy)
>> +{
>> +	regs_user->regs = task_pt_regs(current);
>> +	regs_user->abi  = perf_reg_abi(current);
>> +}
> cheers
>
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