On Tue, Aug 20, 2024 at 04:28:21PM +0100, Mark Brown wrote: > On Tue, Aug 20, 2024 at 03:59:21PM +0100, Catalin Marinas wrote: > > On Mon, Aug 19, 2024 at 05:33:24PM +0100, Mark Brown wrote: > > > On Mon, Aug 19, 2024 at 10:10:36AM +0100, Catalin Marinas wrote: > > > > Is there any arch restriction with setting BTI and GCS? It doesn't make > > > > sense but curious if it matters. We block the exec permission anyway > > > > (unless the BTI pages moved to PIE as well, I don't remember). > > > > As you say BTI should be meaningless for a non-executable page like GCS, > > > I'm not aware of any way in which it matters. BTI is separate to PIE. > > > My thoughts were whether we can get rid of this hunk entirely by > > handling it in the core code. We'd allow BTI if one wants such useless > > combination but clear VM_MAYEXEC in the core code (and ignore VM_SHARED > > since you can't set it anyway). > > I have to admit that the BTI because I was shoving _EXEC in there rather > than because it specifically needed to be blocked. So change the check > for VM_SHARED to a VM_WARN_ON(), and leave the _EXEC check for now > pending the above core change? Yes, sounds good. -- Catalin
