[PATCH 0/5] Enable PAC support in elfutils

[Steve Capper]

On 21/08/2024 00:34, Mark Wielaard wrote:
> Hi Steve,
> 

Hey Mark,

> 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.
> 

Thanks!

> 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.
> 

Yeah, I know what you mean. There's some #ifdef AARCH64 stuff too.

I have removed dwfl_thread_state_aarch64_pauth and have rolled the 
functionality into dwfl_thread_state_registers. It looks a lot tidier 
now thanks :-).

Just giving the revised series a few tests and will send out a V2 shortly.

Cheers,
-- 
Steve