Re: [PATCH v3 18/39] x86/ibt,ftrace: Make function-graph play nice

Peter Zijlstra
2022-03-04T19:58:25Z

On Fri, Mar 04, 2022 at 09:51:54AM -0800, Josh Poimboeuf wrote:
> On Thu, Mar 03, 2022 at 12:23:39PM +0100, Peter Zijlstra wrote:
> > +
> > + addq $16, %rsp
> > + ANNOTATE_INTRA_FUNCTION_CALL
> > + call .Ldo_rop
> > + int3
> > +.Ldo_rop:
> > + mov %rdi, (%rsp)
> > + UNWIND_HINT_FUNC
> > + RET
>
> Why the int3?

Speculation trap :-) Either I'm too paranoid or not paranoid enough; but
without it it's just too close to a retpoline and it doesn't feel right.