[PATCH 9/9] ARM: add UEFI stub support
ard.biesheuvel at linaro.org
Fri Oct 2 11:07:09 PDT 2015
On 2 October 2015 at 20:03, Ard Biesheuvel <ard.biesheuvel at linaro.org> wrote:
> On 2 October 2015 at 18:29, Ryan Harkin <ryan.harkin at linaro.org> wrote:
>> Hi Ard/Roy,
>> On 1 October 2015 at 18:04, Ard Biesheuvel <ard.biesheuvel at linaro.org>
>>> From: Roy Franz <roy.franz at linaro.org>
>>> This patch adds EFI stub support for the ARM Linux kernel.
>>> The EFI stub operates similarly to the x86 and arm64 stubs: it is a
>>> shim between the EFI firmware and the normal zImage entry point, and
>>> sets up the environment that the zImage is expecting. This includes
>>> optionally loading the initrd and device tree from the system partition
>>> based on the kernel command line.
>>> Signed-off-by: Roy Franz <roy.franz at linaro.org>
>>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
>>> arch/arm/Kconfig | 19 +++
>>> arch/arm/boot/compressed/Makefile | 5 +-
>>> arch/arm/boot/compressed/efi-header.S | 130 ++++++++++++++++++++
>>> arch/arm/boot/compressed/efi-stub.c | 89 ++++++++++++++
>>> arch/arm/boot/compressed/head.S | 54 +++++++-
>>> arch/arm/boot/compressed/vmlinux.lds.S | 7 ++
>>> arch/arm/include/asm/efi.h | 23 ++++
>>> drivers/firmware/efi/libstub/Makefile | 12 ++
>>> 8 files changed, 336 insertions(+), 3 deletions(-)
>>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
>>> index e4b7d6cfd8eb..6d7fd83c2ee4 100644
>>> --- a/arch/arm/Kconfig
>>> +++ b/arch/arm/Kconfig
>>> @@ -2061,6 +2061,25 @@ config AUTO_ZRELADDR
>>> 0xf8000000. This assumes the zImage being placed in the first
>>> from start of memory.
>>> +config EFI_STUB
>>> + bool
>>> +config EFI
>>> + bool "UEFI runtime support"
>>> + depends on OF && !CPU_BIG_ENDIAN && MMU && AUTO_ZRELADDR &&
>>> + select UCS2_STRING
>>> + select EFI_PARAMS_FROM_FDT
>>> + select EFI_STUB
>>> + select EFI_ARMSTUB
>>> + select EFI_RUNTIME_WRAPPERS
>> Should we make this "default y" like ARM64? I think so.
> It is not necessarily something that should be enabled by default,
> imo. The distro kernels will probably enabled it, which is good enough
> for me.
>>> + ---help---
>>> + This option provides support for runtime services provided
>>> + by UEFI firmware (such as non-volatile variables, realtime
>>> + clock, and platform reset). A UEFI stub is also provided to
>>> + allow the kernel to be booted as an EFI application. This
>>> + is only useful for kernels that may run on systems that have
>>> + UEFI firmware.
>>> menu "CPU Power Management"
>>> diff --git a/arch/arm/boot/compressed/Makefile
>>> index 3f9a9ebc77c3..0e5624d6215d 100644
>>> --- a/arch/arm/boot/compressed/Makefile
>>> +++ b/arch/arm/boot/compressed/Makefile
>>> @@ -167,9 +167,12 @@ if [ $(words $(ZRELADDR)) -gt 1 -a
>>> "$(CONFIG_AUTO_ZRELADDR)" = "" ]; then \
>>> false; \
>>> +efi-obj-$(CONFIG_EFI_STUB) := $(obj)/efi-stub.o $(obj)/efi-banner.o \
>> When I try to compile the kernel from your branch, I get:
>> make: *** No rule to make target 'arch/arm/boot/compressed/efi-banner.o',
>> needed by 'arch/arm/boot/compressed/vmlinux'. Stop.
>> Did I miss something or is this a problem?
> It was I who missed something: I have been reshuffling some bits, and
> this fell through the cracks. I didn't spot it since I apparently did
> not try to rebuild it cleanly.
> I would like to get rid of the linux_banner reference in the stub
> completely, and I posted a patch here
> In the mean time, could you try with this folded in?
> diff --git a/arch/arm/boot/compressed/Makefile
> index 0e5624d6215d..a6aa7f9123a2 100644
> --- a/arch/arm/boot/compressed/Makefile
> +++ b/arch/arm/boot/compressed/Makefile
> @@ -170,6 +170,10 @@ fi
> efi-obj-$(CONFIG_EFI_STUB) := $(obj)/efi-stub.o $(obj)/efi-banner.o \
> +$(obj)/efi-banner.o: OBJCOPYFLAGS=-j .rodata
> +$(obj)/efi-banner.o: $(objtree)/init/version.o FORCE
> + $(call if_changed,objcopy)
> $(obj)/vmlinux: $(obj)/vmlinux.lds $(obj)/$(HEAD) $(obj)/piggy.$(suffix_y).o \
> $(addprefix $(obj)/, $(OBJS)) $(lib1funcs) $(ashldi3) \
> $(bswapsdi2) $(efi-obj-y) FORCE
> diff --git a/drivers/firmware/efi/libstub/fdt.c
> index a7e87cd582f2..f45a6f715e73 100644
> --- a/drivers/firmware/efi/libstub/fdt.c
> +++ b/drivers/firmware/efi/libstub/fdt.c
> @@ -16,6 +16,8 @@
> #include "efistub.h"
> +extern __attribute__((__visibility__("hidden"))) const char linux_banner;
> efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt,
> unsigned long orig_fdt_size,
> void *fdt, int new_fdt_size, char *cmdline_ptr,
> Thanks for testing!
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