[PATCH 1/1] efi_loader: QEMU CONFIG_EFI_GRUB_ARM32_WORKAROUND=n

[Mark Kettenis]

> From: Heinrich Schuchardt <xypron.glpk at gmx.de>
> Date: Thu, 17 Sep 2020 20:03:24 +0200
> 
> On 9/17/20 7:47 PM, Tom Rini wrote:
> > On Thu, Sep 17, 2020 at 07:18:08PM +0200, Heinrich Schuchardt wrote:
> >
> >> CONFIG_EFI_GRUB_ARM32 is only needed for architectures with caches that are
> >> not managed via CP15 (or for some outdated buggy versions of GRUB). It
> >> makes more sense to disable the setting per architecture than per defconfig.
> >>
> >> Move QEMU's CONFIG_EFI_GRUB_ARM32_WORKAROUND=n from defconfig to Kconfig.
> >>
> >> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
> >> ---
> >>  configs/qemu_arm_defconfig | 1 -
> >>  lib/efi_loader/Kconfig     | 1 +
> >>  2 files changed, 1 insertion(+), 1 deletion(-)
> >
> > Why?  Are we about to move this to be a short list of "default y if ..."
> > instead?  Otherwise no, this is the level of detail that should be in a
> > defconfig I think and not Kconfig.
> >
> 
> Hello Tom,
> 
> yes, in the long run I want to turn this into "default y if". But I
> first need to a list of all ARCH_* which have a cache which is not
> controlled via CP15.

It is fairly standard for SoCs with Cortex-A9 cores.  Maybe some SoCs
with Cortex-A8 are affected as well.  Probably the list of affected
SoCs is those that implement v7_outer_cache_enable().

However, since other 32-bit ARM UEFI implementation are generally not
unavailable, I'm not sure disabling this workaround on other SoCs is
feasable since the code oath for booting OSes without the MMU enabled
may not be very well tested.