[PATCH 0/5] Enable PAC support in elfutils

[Mark Wielaard]

Hi Steve,

On Fri, Jun 14, 2024 at 03:47:14PM +0100, Steve Capper wrote:
> This series enables Pointer Authentication (PAC) support in elfutils.
> 
> The first four patches were originally posted by German Gomez. I've
> rebased to the latest elfutils and added an extra patch that was
> required to debug core dumps from PAC enabled applications.
> 
> These patches were tested on Debian Testing and Fedora 40 running on an
> Apple M1 MacBook Pro (the CFLAG -mbranch-protection=standard needs to be
> supplied to the build).

Thanks, I found a setup to test this and it works. Nice.

> Without this series applied, the following tests failed:
>  * run-backtrace-native.sh
>  * run-backtrace-dwarf.sh
>  * run-backtrace-native-core.sh
>  * run-deleted.sh
>
> I am happy to chop/change bits as necessary. 

I had some small comments on the first two patches. They look good,
just tiny nitpicks.

The last three introduce/depend on a new public function
dwfl_thread_state_aarch64_pauth. I rather not have such a public
architecture specific function.

Could we instead try to reuse dwfl_thread_state_registers?  We could
say that negative regnums are special architecture specific settings?
There is already some precedent for that in the the
thread_state_registers_cb function given to
ebl_set_initial_registers_tid, which call with -1 to set the PC
value. We could use -2 to indicate it is an arch specific setting.

That is also slightly ugly. But given we can hide most of it in
architecture specific/private code better than special case public
architecture functions.

Cheers,

Mark