Re: [PATCH] powerpc/32: indirect function call use bctrl rather than blrl in ret_from_kernel_thread

From: Segher Boessenkool
Date: Fri Aug 20 2021 - 13:24:25 EST


On Fri, Aug 20, 2021 at 10:15:11PM +1000, Michael Ellerman wrote:
> Christophe Leroy <christophe.leroy@xxxxxxxxxx> writes:
> > Copied from commit 89bbe4c798bc ("powerpc/64: indirect function call
> > use bctrl rather than blrl in ret_from_kernel_thread")
> >
> > blrl is not recommended to use as an indirect function call, as it may
> > corrupt the link stack predictor.
>
> Do we know if any 32-bit CPUs have a link stack predictor or similar?

74xx do.


Segher