On 09.01.26 12:34, Simon Glass wrote: > Hi Mark, > > On Wed, 7 Jan 2026 at 12:38, Mark Kettenis <[email protected]> wrote: >> >>> From: Simon Glass <[email protected]> >>> Date: Wed, 7 Jan 2026 12:02:27 -0700 >>> >>> On Tue, 6 Jan 2026 at 19:42, Peter Robinson <[email protected]> wrote: >>>> >>>> On Wed, 7 Jan 2026 at 00:33, Simon Glass <[email protected]> wrote: >>>>> >>>>> From: Simon Glass <[email protected]> >>>>> >>>>> This work-around dates from 2019 and grub 2.04 which is quite old. New >>>>> builds of grub don't have the problem and old boards presumably use an >>>>> older U-Boot, so don't need this. >>>>> >>>>> Drop it. >>>>> >>>>> Signed-off-by: Simon Glass <[email protected]> >>>>> Signed-off-by: Simon Glass <[email protected]> >>>>> --- >>>>> >>>>> configs/mt7623n_bpir2_defconfig | 1 - >>>>> lib/efi_loader/Kconfig | 10 ---------- >>>>> lib/efi_loader/efi_boottime.c | 26 -------------------------- >>>>> 3 files changed, 37 deletions(-) >>>>> >>>>> diff --git a/configs/mt7623n_bpir2_defconfig >>>>> b/configs/mt7623n_bpir2_defconfig >>>>> index 404380558f2..d75168a72ed 100644 >>>>> --- a/configs/mt7623n_bpir2_defconfig >>>>> +++ b/configs/mt7623n_bpir2_defconfig >>>>> @@ -13,7 +13,6 @@ CONFIG_DEFAULT_DEVICE_TREE="mt7623n-bananapi-bpi-r2" >>>>> CONFIG_TARGET_MT7623=y >>>>> CONFIG_SYS_BOOTM_LEN=0x4000000 >>>>> CONFIG_SYS_LOAD_ADDR=0x84000000 >>>>> -# CONFIG_EFI_GRUB_ARM32_WORKAROUND is not set >>>>> CONFIG_FIT=y >>>>> CONFIG_FIT_VERBOSE=y >>>>> CONFIG_DISTRO_DEFAULTS=y >>>>> diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig >>>>> index 13e44be1d06..5585c841c27 100644 >>>>> --- a/lib/efi_loader/Kconfig >>>>> +++ b/lib/efi_loader/Kconfig >>>>> @@ -505,16 +505,6 @@ config EFI_LOADER_BOUNCE_BUFFER >>>>> hardware we can create a bounce buffer so that payloads don't >>>>> have to >>>>> worry about platform details. >>>>> >>>>> -config EFI_GRUB_ARM32_WORKAROUND >>>>> - bool "Workaround for GRUB on 32bit ARM" >>>>> - default n if ARCH_BCM283X || ARCH_SUNXI || ARCH_QEMU >>>>> - default y >>>>> - depends on ARM && !ARM64 >>>>> - help >>>>> - GRUB prior to version 2.04 requires U-Boot to disable caches. >>>>> This >>>>> - workaround currently is also needed on systems with caches that >>>>> - cannot be managed via CP15. >>>> >>>> This also states that it's needed for systems that can't be managed by >>>> CP15, what systems are they, how are those platforms addressed? >>> >>> I'm guessing that some systems have level2 caches with their own >>> software interface. I certainly have seen this with Tegra2/3, for >>> example. >> >> This is already being discussed in another thread on the mailing list >> started by Jan Kiszka: >> >> https://lists.denx.de/pipermail/u-boot/2026-January/606817.html >> >> My suggestion would be to drop this patch from your set and let that >> thread run its course. > > Yes I did see that and I was pleased to see that someone else was > interested in this topic. > > Still, that thread does not actually include a patch. So let's see how > it pans out. >
I'm played with turning off the workaround on a socfpga target, and that apparently causes troubles: https://lore.kernel.org/cip-dev/[email protected]/ I'm inclined now to keep cache disabling by default, only enable caches on known-good boards. If someone has a hint how to reliable identify targets that have architected CR15 cache control, I would use that as input. Otherwise, we need to maintain a positive list in Kconfig. Along that, the control may need renaming because the original reason - broken bootloaders - is really history. Jan -- Siemens AG, Foundational Technologies Linux Expert Center
