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| author |   Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2018-07-11 11:40:38 +0200 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2018-07-16 00:43:12 +0200 |
| commit | 3d7ee348aa4127a7893c11261da9b76371a970e6 (patch) | |
| tree | b3dee7e3ebdf9d4ddce9cd259031fce35ed145e5 /drivers/firmware/efi/Kconfig | |
| parent | efi: Remove the declaration of efi_late_init() as the function is unused (diff) | |
| download | linux-dev-3d7ee348aa4127a7893c11261da9b76371a970e6.tar.xz linux-dev-3d7ee348aa4127a7893c11261da9b76371a970e6.zip | |
efi/libstub/arm: Add opt-in Kconfig option for the DTB loader
There are various ways a platform can provide a device tree binary
to the kernel, with different levels of sophistication:
- ideally, the UEFI firmware, which is tightly coupled with the
platform, provides a device tree image directly as a UEFI
configuration table, and typically permits the contents to be
manipulated either via menu options or via UEFI environment
variables that specify a replacement image,
- GRUB for ARM has a 'devicetree' directive which allows a device
tree image to be loaded from any location accessible to GRUB, and
supersede the one provided by the firmware,
- the EFI stub implements a dtb= command line option that allows a
device tree image to be loaded from a file residing in the same
file system as the one the kernel image was loaded from.
The dtb= command line option was never intended to be more than a
development feature, to allow the other options to be implemented
in parallel. So let's make it an opt-in feature that is disabled
by default, but can be re-enabled at will.
Note that we already disable the dtb= command line option when we
detect that we are running with UEFI Secure Boot enabled.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Alexander Graf <agraf@suse.de>
Acked-by: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20180711094040.12506-7-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/firmware/efi/Kconfig')
| -rw-r--r-- | drivers/firmware/efi/Kconfig | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig index 781a4a337557..d8e159feb573 100644 --- a/drivers/firmware/efi/Kconfig +++ b/drivers/firmware/efi/Kconfig @@ -87,6 +87,18 @@ config EFI_RUNTIME_WRAPPERS config EFI_ARMSTUB bool +config EFI_ARMSTUB_DTB_LOADER + bool "Enable the DTB loader" + depends on EFI_ARMSTUB + help + Select this config option to add support for the dtb= command + line parameter, allowing a device tree blob to be loaded into + memory from the EFI System Partition by the stub. + + The device tree is typically provided by the platform or by + the bootloader, so this option is mostly for development + purposes only. + config EFI_BOOTLOADER_CONTROL tristate "EFI Bootloader Control" depends on EFI_VARS |