[PATCH 09/10] efi: Drop EFI_GRUB_ARM32_WORKAROUND

[Peter Robinson]

On Wed, 7 Jan 2026 at 00:33, Simon Glass <sjg at chromium.org> wrote:
>
> From: Simon Glass <sjg at chromium.org>
>
> 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 <sjg at chromium.org>
> Signed-off-by: Simon Glass <simon.glass at canonical.com>
> ---
>
>  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?

>  config EFI_ESRT
>         bool "Enable the UEFI ESRT generation"
>         depends on EFI_CAPSULE_FIRMWARE_MANAGEMENT
> diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
> index 0bc66ee61a8..c31ee53cde6 100644
> --- a/lib/efi_loader/efi_boottime.c
> +++ b/lib/efi_loader/efi_boottime.c
> @@ -2139,29 +2139,6 @@ error:
>         return EFI_EXIT(ret);
>  }
>
> -/**
> - * efi_exit_caches() - fix up caches for EFI payloads if necessary
> - */
> -static void efi_exit_caches(void)
> -{
> -#if defined(CONFIG_EFI_GRUB_ARM32_WORKAROUND)
> -       /*
> -        * Boooting Linux via GRUB prior to version 2.04 fails on 32bit ARM if
> -        * caches are enabled.
> -        *
> -        * TODO:
> -        * According to the UEFI spec caches that can be managed via CP15
> -        * operations should be enabled. Caches requiring platform information
> -        * to manage should be disabled. This should not happen in
> -        * ExitBootServices() but before invoking any UEFI binary is invoked.
> -        *
> -        * We want to keep the current workaround while GRUB prior to version
> -        * 2.04 is still in use.
> -        */
> -       cleanup_before_linux();
> -#endif
> -}
> -
>  /**
>   * efi_exit_boot_services() - stop all boot services
>   * @image_handle: handle of the loaded image
> @@ -2245,9 +2222,6 @@ static efi_status_t EFIAPI efi_exit_boot_services(efi_handle_t image_handle,
>         /* Patch out unsupported runtime function */
>         efi_runtime_detach();
>
> -       /* Fix up caches for EFI payloads if necessary */
> -       efi_exit_caches();
> -
>         /* Disable boot time services */
>         systab.con_in_handle = NULL;
>         systab.con_in = NULL;
> --
> 2.43.0
>