Re: [PATCH v2 1/3] perf/sdt/x86: Add renaming logic for (missing) 8 bit registers

From: Ravi Bangoria
Date: Tue Mar 28 2017 - 02:55:25 EST


Hi Masami, Thanks for the review.

On Monday 27 March 2017 07:47 PM, Masami Hiramatsu wrote:
> On Mon, 27 Mar 2017 13:28:27 +0530
> Ravi Bangoria <ravi.bangoria@xxxxxxxxxxxxxxxxxx> wrote:
>
>> I found couple of events using al, bl, cl and dl registers for
>> argument. These are not directly accepted by uprobe_events and
>> thus needs to be mapped to ax, bx, cx and dx respectively.
>>
>> Few ex,
>>
>> /usr/bin/qemu-system-s390x
>> css_adapter_interrupt: 1@%bl
>> css_chpid_add: 1@%cl 1@%sil 1@%dl
>> dma_bdrv_io: 8@%rbx 8@%rbp -8@%r14 1@%al
>>
>> /usr/bin/postgres
>> buffer__read__done: ... -1@-bash -1@%al
>> buffer__read__start: ... -1@%al
> Of course, it should be suppoted. BTW, wouldn't we take care about ah, bh ... too?

I thought about them while preparing this patch, but I couldn't find any
events using those registers. So I ignored them.

But I think no one stops compiler to use those registers for sdt argument.
And if so, they should get included.

Will send v3 for this.

Thanks,
Ravi