Re: [PATCH 00/24] objtool: retpoline and asm-goto validation

[Peter Zijlstra]

On Tue, Jan 23, 2018 at 03:57:39PM +0000, David Woodhouse wrote:
> On Tue, 2018-01-23 at 16:42 +0100, Peter Zijlstra wrote:
> > drivers/watchdog/.tmp_hpwdt.o: warning: objtool: .text+0x24: indirect call found in RETPOLINE build
> 
> You're calling into BIOS there. Not a lot of point in protecting that
> one. This is one of the cases where we were saying you needed to turn
> on IBRS to have complete protection, even with retpoline.
> 

That code looked entirely dodgy, which is why I left it. I can easily
add the ANNOTATE_RETPOLINE_SAFE thing to shut it up, but given it is an
actual problem, maybe we should just keep it?