On Fri, 12 Jun 2020 at 00:43, Russell King - ARM Linux admin <linux@xxxxxxxxxxxxxxx> wrote: > > On Fri, Jun 12, 2020 at 12:39:08AM +0200, Ard Biesheuvel wrote: > > On Fri, 12 Jun 2020 at 00:38, Russell King - ARM Linux admin > > <linux@xxxxxxxxxxxxxxx> wrote: > > > > > > On Fri, Jun 12, 2020 at 12:18:43AM +0200, Ard Biesheuvel wrote: > > > > I've given this a spin myself on a RPi4 running 32-bit U-boot, and > > > > everything works as expected, both with and without the GRUB hack > > > > enabled. > > > > > > > > Russell, given that this only affects code inside #ifdef > > > > CONFIG_EFI_STUB, do you have any objections to me taking this as a fix > > > > via the EFI tree? I have a set of fixes I need to queue up and send > > > > out anyway, and I intend to do so early next week. > > > > > > Please don't, I'll be basing my branches off -rc1 (as normal), and if > > > you then submit this as a fix through the EFI tree for merging after > > > rc1, and then send me further EFI work to go through the ARM tree, > > > we'll end up in exactly the same merge issues as we did prior to this > > > merge window. > > > > > > > Fair enough. What do you suggest instead? Shall I drop this into the > > patch system? > > Is it a regression? If so, sending it prior to -rc1 is permissible. > If not, please drop it in the patch system. > If you boot via the EFI stub in HYP mode with the caches off (or with U-boot's GRUB hack enabled which fiddles with the caches halfway through), it appears that you cannot boot current mainline. This is an oversight on my part - the EFI spec does not permit doing either of those things, and while EDK2 behaves in this regard, u-boot can be configured in various different non-conforming ways. (Note that v5.7 and before will leave the MMU and caches enabled at HYP upon entering the kernel proper after booting via EFI, so this is not something that was 100% correct before, but at least it booted most of the time) So this is a regression, but since the EFI tree goes through -tip, I won't be able to get this fix in before -rc1 is released. Therefore, I will be dropping this into the patch system in any case, and leave it up to you to decide when it gets sent onwards.
