On 09/12/2017 05:00 AM, Bin Meng wrote:

Hi Heinrich,

On Sun, Sep 10, 2017 at 4:55 PM, Heinrich Schuchardt xypron.glpk@gmx.de wrote:

...

Variable EFI_LDS is set based on CONFIG_EFI_STUB_64BIT. It influences which lds script is used for compiling helloworld.efi. This results in building helloworld.efi failing on x86_64 if CONFIG_EFI_STUB_64BIT is not set. CONFIG_EFI_STUB_64BIT is only visible if EFI_STUB is selected. We should be able to compile a 64bit helloworld.efi irrespective of EFI_STUB.

With the patch the bitness of the efi build is taken from the architecture choice.

Signed-off-by: Heinrich Schuchardt xypron.glpk@gmx.de

For proper testing https://lists.denx.de/pipermail/u-boot/2017-September/305184.html must be fixed.

So I send this as RFC.

Sorry I missed this. This does not go to the U-Boot ML. Did you intend to keep the discussion among us?

CC: U-Boot Mailing List u-boot@lists.denx.de

...

Alex, do you remember why CONFIG_EFI_STUB_64BIT was introduced in the first place.

The CONFIG_EFI_STUB_64BIT was introduced to support booting from a 64-bit EFI BIOS.

...

Would you ever use a stub with a different bitness than U-Boot?

Yes, for example U-Boot x86 32-bit to boot a 64-bit EFI payload.

My understanding is that the EFI stub is used if U-Boot is loaded as an EFI application.

It has nothing to do with the EFI application or driver loaded by U-boot's bootefi command, which I assume you reference as "to boot a 64-bit EFI payload".

A stub with different bitness than U-Boot would be needed if we wanted to load 64 bit U-Boot as a 32 bit EFI application or a 32 bit U-Boot as a 64 bit EFI application. Is this required in any scenario?

Regards

Heinrich

...

Regards

Heinrich

arch/x86/config.mk | 12 ++++++------ lib/efi/Kconfig | 18 ------------------ 2 files changed, 6 insertions(+), 24 deletions(-)

diff --git a/arch/x86/config.mk b/arch/x86/config.mk index fe8639aef6..a87dd33837 100644 --- a/arch/x86/config.mk +++ b/arch/x86/config.mk @@ -93,16 +93,16 @@ endif

ifneq ($(CONFIG_EFI_STUB)$(CONFIG_CMD_BOOTEFI_HELLO_COMPILE)$(CONFIG_CMD_SELFTEST_COMPILE),)

-ifneq ($(CONFIG_EFI_STUB_64BIT),) -EFI_LDS := elf_x86_64_efi.lds -EFI_CRT0 := crt0_x86_64_efi.o -EFI_RELOC := reloc_x86_64_efi.o -EFI_TARGET := --target=efi-app-ia32 -else +ifeq ($(IS_32BIT),y) EFI_LDS := elf_ia32_efi.lds EFI_CRT0 := crt0_ia32_efi.o EFI_RELOC := reloc_ia32_efi.o EFI_TARGET := --target=efi-app-x86_64 +else +EFI_LDS := elf_x86_64_efi.lds +EFI_CRT0 := crt0_x86_64_efi.o +EFI_RELOC := reloc_x86_64_efi.o +EFI_TARGET := --target=efi-app-ia32 endif

endif diff --git a/lib/efi/Kconfig b/lib/efi/Kconfig index 919e314a0c..8c0bc2a529 100644 --- a/lib/efi/Kconfig +++ b/lib/efi/Kconfig @@ -34,21 +34,3 @@ config EFI_RAM_SIZE use. U-Boot allocates this from EFI on start-up (along with a few other smaller amounts) and it can never be increased after that. It is used as the RAM size in with U-Boot.

-choice

•   prompt "EFI 32/64-bit selection"
  

•   depends on EFI_STUB
  

•   help
  

•     EFI does not support mixing 32-bit and 64-bit modes. This is a
  

•     significant problem because it means that you must build a stub with
  

•     the correct type for EFI to load it correctly. If you are using
  

•     32-bit EFI, select 32-bit here, else select 64-bit. Failure to do
  

•     this may produce no error message - it just won't start!
  

-config EFI_STUB_32BIT

•   bool "Produce a stub for running with 32-bit EFI"
  

-config EFI_STUB_64BIT

•   bool "Produce a stub for running with 64-bit EFI"
  

-endchoice

Regards, Bin