Re: [PATCH 1/3] powerpc: Emulation support for load/store instructions on LE

From: Ravi Bangoria
Date: Fri Nov 04 2016 - 01:31:48 EST




On Friday 04 November 2016 07:37 AM, Andrew Donnellan wrote:
> On 03/11/16 21:27, Ravi Bangoria wrote:
>> Yes, kernel-space hw-breakpoint feature is broken on LE without this.
>
> Is there any actual user-visible feature that depends on this, or is this solely for debugging and development purposes?
>
> It would of course be *nice* to have it in stable trees (particularly so we pick it up in distros) but I'm not convinced that enabling HW breakpoints on a platform where it has *never* worked qualifies as an "actual bug".
>
> (BTW many thanks for fixing this - I had a shot at it late last year but never quite got there!)

Thanks Andrew,

kprobe, uprobe, hw-breakpoint and xmon are the only user of emulate_step.

Kprobe / uprobe single-steps instruction if they can't emulate it, so there
is no problem with them. As I mention, hw-breakpoint is broken. However
I'm not sure about xmon, I need to check that.

So yes, there is no user-visible feature that depends on this.

-Ravi