On 2 October 2015 at 18:29, Ryan Harkin <ryan.harkin@xxxxxxxxxx> wrote:
> Hi Ard/Roy,
>
> On 1 October 2015 at 18:04, Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> wrote:
>>
>> From: Roy Franz <roy.franz@xxxxxxxxxx>
>>
>> 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@xxxxxxxxxx>
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
>> ---
>> 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
>> 128MB
>> from start of memory.
>>
>> +config EFI_STUB
>> + bool
>> +
>> +config EFI
>> + bool "UEFI runtime support"
>> + depends on OF && !CPU_BIG_ENDIAN && MMU && AUTO_ZRELADDR &&
>> !XIP_KERNEL
>> + 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.
>> +
>> endmenu
>>
>> menu "CPU Power Management"
>> diff --git a/arch/arm/boot/compressed/Makefile
>> b/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; \
>> fi
>>
>> +efi-obj-$(CONFIG_EFI_STUB) := $(obj)/efi-stub.o $(obj)/efi-banner.o \
>
>
> When I try to compile the kernel from your branch, I get:
>
> make[2]: *** No rule to make target 'arch/arm/boot/compressed/efi-banner.o',
> needed by 'arch/arm/boot/compressed/vmlinux'. Stop.
>
> Did I miss something or is this a problem?
>
It was I who missed something: I have been reshuffling some bits, and
this fell through the cracks. I didn't spot it since I apparently did
not try to rebuild it cleanly.
I would like to get rid of the linux_banner reference in the stub
completely, and I posted a patch here
In the mean time, could you try with this folded in?
-------------------8<--------------------
diff --git a/arch/arm/boot/compressed/Makefile
b/arch/arm/boot/compressed/Makefile
index 0e5624d6215d..a6aa7f9123a2 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -170,6 +170,10 @@ fi
efi-obj-$(CONFIG_EFI_STUB) := $(obj)/efi-stub.o $(obj)/efi-banner.o \
$(objtree)/drivers/firmware/efi/libstub/lib.a
+$(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
b/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,
-------------------8<--------------------
Thanks for testing!
--
Ard.
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