Re: [PATCH 2/5] gcc-plugins/stackleak: Use asm instrumentation to avoid useless register saving

Kees Cook
2020-06-10T20:03:31Z

On Wed, Jun 10, 2020 at 06:47:14PM +0300, Alexander Popov wrote:
> On 09.06.2020 21:46, Kees Cook wrote:
> The inline asm statement that is used for instrumentation is arch-specific.
> Trying to add
> asm volatile("call stackleak_track_stack")
> in gcc plugin on aarch64 makes gcc break spectacularly.

Ah! Thank you, that eluded my eyes. :)

> I pass the target arch name to the plugin and check it explicitly to avoid that.
>
> Moreover, I'm going to create a gcc enhancement request for supporting
> no_caller_saved_registers attribute on aarch64.

For arm64 right now it looks like the plugin will just remain
"inefficient" in these cleanup, as before, yes?

--
Kees Cook