This is my (now quite late) Christmas present for my openSUSE friends :).
U-Boot is a great project for embedded devices. However, convincing everyone involved that only for "a few oddball ARM devices" we need to support different configuration formats from grub2 when all other platforms (PPC, System Z, x86) are standardized on a single format is a nightmare.
So we started to explore alternatives. At first, people tried to get grub2 running using the u-boot api interface. However, FWIW that one doesn't support relocations, so you need to know where to link grub2 to at compile time. It also seems to be broken more often than not. And on top of it all, it's a one-off interface, so yet another thing to maintain.
That led to a nifty idea. What if we can just implement the EFI application protocol on top of U-Boot? Then we could compile a single grub2 binary for uEFI based systems and U-Boot based systems and as soon as that one's loaded, everything looks and feels (almost) the same.
This patch set is the result of pursuing this endeavor.
- I am successfully able to run grub2 and Linux EFI binaries with this code. - When enabled, the resulting U-Boot binary only grows by ~10kb, so it's very light weight. - It works on 32bit ARM and AArch64. - All storage devices are directly accessible - No EFI variables - Removable media booting (search for /efi/boot/boota{a64,arm}.efi) - Everything in place for runtime service support
Of course, there are still a few things one could do on top:
- Improve disk media detection (don't scan, use what information we have) - Add EFI variable support using NVRAM - Add GFX support - Make EFI Shell work ;) - Network device support - Support for payload exit
But so far, I'm very happy with the state of the patches. They completely eliminate potential arguments against U-Boot internally and give users the chance to run with the same level of comfort on all firmware types.
Version 3 was successfully tested to boot grub2 and Linux from there on a HiKey (AArch64, dcache disabled) and on a BeagleBone Black.
If you read this far and want to try out the patches, feel free to grab the source from git at:
https://github.com/agraf/u-boot efi-v3
v1 -> v2: - move memory allocation to separate patch - limit 32/64 to hosts that support it - check 32bit optional nt header magic - switch to GPLv2+ - Fix typo s/does now/does not/ - Add #ifdefs around header to allow inclusion when efi_loader is disabled - Add stub efi_restore_gd() function when efi_loader is disabled - Disable debug - Mark runtime region as such - Fix up memory map - Allow efi_restore_gd to be called before first efi entry - Add 32bit arm cache workaround - Move memory map to separate patch - Change BTS version to 2.5 - Fix return values for a few callbacks to more EFI compliant ones - Change vendor to "Das U-Boot" - Add warning when truncating timer trigger - Add runtime detach - Enable runtime relocations - Add get_time - Fix relocation - Fix 32bit - Add am335x support - Move section definition to header - Add systab to runtime section - Add self-relocation hook table - Relocate efi_runtime section early during bootup - Fix return values for a number of callbacks to be more UEFI compliant - Move to block_drvr array - Fix header order - Document efi block object struct - Use calloc rather than malloc & memset - Default to y - New patches: - disk/part.c: Expose list of available block drivers - arm64: Allow exceptions to return - arm64: Allow EFI payload code to take exceptions - efi_loader: Add DCACHE_OFF support for arm64 - efi_loader: Add distro boot script for removable media
v2 -> v3:
- Add EFIAPI to notify_function - Add access denied code - use efi_alloc - add EFIAPI to function prototypes - remove unused macros - reorder header inclusion - split relocation code into function - flush cache after loading - Use external efi_memory helpers - Add EFIAPI to function prototypes - Initialize event timer to -1ULL to prevent early firing - Document header - Move obj list to lib - Remove implicit guid table - Add guid compare function - Fix return values - Implement efi_wait_for_event - Add EFIAPI to function prototypes - Patch reset to NULL - Add EFIAPI to function prototypes - Document header - Add dm.h include - Remove non-dm rtc support - Return DEVICE_ERROR in rtc path - Adapt to newer u-boot block API - Add EFIAPI to function prototypes - Document header - Check for DEV_TYPE_UNKNOWN - Document 16byte limit for dp string - Move to new cmd directory - Add kconfig option - Fix comment style - Add help text - s/-1/-ENOENT - Move obj list to lib - Rewrite memory allocation and map - Document header - Add memory file - New files: - README patch - MAINTAINERS patch
Alex
Alexander Graf (16): disk/part.c: Expose list of available block drivers include/efi_api.h: Add more detailed API definitions efi_loader: Add PE image loader efi_loader: Add boot time services efi_loader: Add console interface efi_loader: Add runtime services efi_loader: Add disk interfaces efi_loader: Add "bootefi" command efi_loader: Implement memory allocation and map arm64: Allow exceptions to return arm64: Allow EFI payload code to take exceptions efi_loader: Add DCACHE_OFF support for arm64 efi_loader: hook up in build environment efi_loader: Add distro boot script for removable media efi_loader: Add README section in README.efi efi_loader: Add MAINTAINERS entry
MAINTAINERS | 7 + arch/arm/config.mk | 4 + arch/arm/cpu/armv8/exceptions.S | 44 +++ arch/arm/cpu/armv8/u-boot.lds | 16 + arch/arm/cpu/u-boot.lds | 30 ++ arch/arm/lib/Makefile | 3 + arch/arm/lib/interrupts_64.c | 28 ++ arch/arm/lib/sections.c | 4 + arch/arm/lib/unaligned_64.c | 284 ++++++++++++++ board/ti/am335x/u-boot.lds | 30 ++ cmd/Kconfig | 7 + cmd/Makefile | 1 + cmd/bootefi.c | 172 +++++++++ common/board_r.c | 7 + disk/part.c | 7 +- doc/README.efi | 69 +++- include/config_distro_bootcmd.h | 47 ++- include/efi.h | 1 + include/efi_api.h | 198 ++++++++-- include/efi_loader.h | 147 +++++++ include/part.h | 8 + include/pe.h | 263 +++++++++++++ lib/Kconfig | 1 + lib/Makefile | 1 + lib/efi_loader/Kconfig | 9 + lib/efi_loader/Makefile | 12 + lib/efi_loader/efi_boottime.c | 781 ++++++++++++++++++++++++++++++++++++++ lib/efi_loader/efi_console.c | 360 ++++++++++++++++++ lib/efi_loader/efi_disk.c | 218 +++++++++++ lib/efi_loader/efi_image_loader.c | 182 +++++++++ lib/efi_loader/efi_memory.c | 314 +++++++++++++++ lib/efi_loader/efi_runtime.c | 290 ++++++++++++++ 32 files changed, 3500 insertions(+), 45 deletions(-) create mode 100644 arch/arm/lib/unaligned_64.c create mode 100644 cmd/bootefi.c create mode 100644 include/efi_loader.h create mode 100644 include/pe.h create mode 100644 lib/efi_loader/Kconfig create mode 100644 lib/efi_loader/Makefile create mode 100644 lib/efi_loader/efi_boottime.c create mode 100644 lib/efi_loader/efi_console.c create mode 100644 lib/efi_loader/efi_disk.c create mode 100644 lib/efi_loader/efi_image_loader.c create mode 100644 lib/efi_loader/efi_memory.c create mode 100644 lib/efi_loader/efi_runtime.c