Re: [PATCH v3 13/17] arm64: preserve x18 when CPU is suspended

Sami Tolvanen
2019-10-31T17:27:46Z

On Thu, Oct 31, 2019 at 10:18 AM Nick Desaulniers
<ndesaulniers@google.com> wrote:
> > +#ifdef CONFIG_SHADOW_CALL_STACK
> > + ldr x18, [x0, #96]
> > + str xzr, [x0, #96]
>
> How come we zero out x0+#96, but not for other offsets? Is this str necessary?

It clears the shadow stack pointer from the sleep state buffer, which
is not strictly speaking necessary, but leaves one fewer place to find
it.

Sami