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Re: [PATCH] [AARCH64]: Pointer mangling support for Aarch64
- From: Will Newton <will dot newton at linaro dot org>
- To: Tom Tromey <tromey at redhat dot com>
- Cc: Marcus Shawcroft <marcus dot shawcroft at gmail dot com>, Venkataramanan Kumar <venkataramanan dot kumar at linaro dot org>, "libc-ports at sourceware dot org" <libc-ports at sourceware dot org>, Patch Tracking <patch at linaro dot org>
- Date: Fri, 10 Jan 2014 09:54:45 +0000
- Subject: Re: [PATCH] [AARCH64]: Pointer mangling support for Aarch64
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On 7 January 2014 18:10, Tom Tromey <tromey@redhat.com> wrote:
Hi Tom,
> Marcus> Hi, I'm not familiar with the inner workings of STAP probes, can you
> Marcus> explain what the arguments of longjmp_target should be at a semantic
> Marcus> level rather than the proposed location to get the values from?
>
> I was going to say manual/probes.texi but I see the longjmp probes
> aren't documented.
>
> Currently gdb only uses the third argument, which is the target PC.
>
> Marcus> Do we need probes in setjmp aswell?
>
> I think it's nice for users if the probes are the same across ports.
>
> That said, gdb itself only uses the longjmp and rtld probes from glibc.
> gdb users (or SystemTap users) can refer to the other probes though.
Do you know if it is documented anywhere what the difference is
between the longjmp and longjmp_target probes?
It looks like on i386 the registers are restored in between
longjmp/longjmp_target but on powerpc half the registers seem to have
been restored by the time the longjmp probe is executed. AFAICT gdb
does not use the longjmp_target probe either...
Thanks,
--
Will Newton
Toolchain Working Group, Linaro