Date: Wed, 1 Apr 2020 09:31:03 +0900 From: AKASHI Takahiro takahiro.akashi@linaro.org
On Tue, Mar 31, 2020 at 10:20:17AM +0200, Mark Kettenis wrote:
Date: Tue, 31 Mar 2020 16:44:34 +0900 From: AKASHI Takahiro takahiro.akashi@linaro.org
On Tue, Mar 31, 2020 at 08:44:02AM +0200, Heinrich Schuchardt wrote:
On March 31, 2020, 5:28 a.m. UTC Takahiro Akashi wrote:
On Fri, Mar 27, 2020 at 06:27:53AM +0100, Heinrich Schuchardt wrote:
The UEFI spec requires support for the FAT file system.
Signed-off-by: Heinrich Schuchardt xypron.glpk@gmx.de
lib/efi_loader/Kconfig | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig index 9890144d41..e10ca05549 100644 --- a/lib/efi_loader/Kconfig +++ b/lib/efi_loader/Kconfig @@ -15,6 +15,8 @@ config EFI_LOADER select HAVE_BLOCK_DEVICE select REGEX imply CFB_CONSOLE_ANSI
- imply FAT
- imply FAT_WRITE
Obviously, this *imply* doesn't enforce enabling FAT. If it is absolutely necessary, another measure should be taken.
If somebody wants to minimize the U-Boot size it might be necessary to do without FAT_WRITE or FAT support.
If so, Get/SetVariable won't be supported even in boot time with your patch applied. It is not practical for almost all users.
I *strongly* disagree with that statement. Most users don't care about U-Boot providing a full EFI implementation. They just want to boot their OS. The basic EFI support in U-Boot is good enough for that and for OpenBSD and some Linux distros on arm/arm64 this is the only bootpath that works. If adding more code leads to board maintainers disabling EFI support this isn't helpful.
Okay, so can you please describe the minimum set of functionality for you? Without that, the discussion will not be fair.
For OpenBSD/arm and OpenBSD/amr64 we adopted the UEFI interfaces in u-boot early on, even before most Linux distros did. As a result our requirements are very minimal:
Our bootloader uses the folowing boot services:
- HandleProtocol() - AllocatePages() - FreePages() - LocateHandle() - LocateHandleBuffer() - LocateProtocol() - CreateEvent() - SetTimer() - WaitForEvent() - CloseEvent() - GetMemoryMap() - SetWatchdogTimer() - Exit()
runtime services:
- ResetSystem()
and protocols:
- EFI_LOADED_IMAGE_PROTOCOL - EFI_DEVICE_PATH_PROTOCOL - EFI_BLOCK_IO_PROTOCOL - EFI_GRAPHICS_OUTPUT_PROTOCOL - EFI_RNG_PROTOCOL - EFI_SIMPLE_NETWORK_PROTOCOL - EFI_PXE_BASE_CODE_PROTOCOL
Obviously the last four are only used if there is actual hardware to support these protocols. But I'd consider them non-optional if such hardware exists.
Our kernel only uses a couple if runtime services:
- SetVirtualAddressMap() - GetTime() (optional) - SetTime() (optional)
Cheers,
Mark