From: AKASHI Takahiro takahiro.akashi@linaro.org
Under the current implementation, booting from removable media using a architecture-specific default image name, say BOOTAA64.EFI, is supported only in distro_bootcmd script. See the commit 74522c898b35 ("efi_loader: Add distro boot script for removable media").
This is, however, half-baked implementation because 1) UEFI specification requires this feature to be implemented as part of Boot Manager's responsibility:
3 - Boot Manager 3.5.1 Boot via the Simple File Protocol When booting via the EFI_SIMPLE_FILE_SYSTEM_PROTOCOL, the FilePath will start with a device path that points to the device that implements the EFI_SIMPLE_FILE_SYSTEM_PROTOCOL or the EFI_BLOCK_IO_PROTOCOL. The next part of the FilePath may point to the file name, including subdirectories, which contain the bootable image. If the file name is a null device path, the file name must be generated from the rules defined below. ... 3.5.1.1 Removable Media Boot Behavior To generate a file name when none is present in the FilePath, the firmware must append a default file name in the form \EFI\BOOT\BOOT{machine type short-name}.EFI ...
2) So (1) entails the hehavior that the user's preference of boot media order should be determined by Boot#### and BootOrder variables.
With this patch, the semantics mentioned above is fully implemented. For example, if you want to boot the system from USB and SCSI in this order, * define Boot0001 which contains only a device path to the USB device (without any file path/name) * define Boot0002 which contains only a device path to the SCSI device, and * set BootOrder to Boot0001:Boot0002
Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org Signed-off-by: Masahisa Kojima masahisa.kojima@linaro.org --- Changes from original version: - create new include file "efi_default_filename.h" to avoid conflict with config_distro_bootcmd.h - modify the target pointer of efi_free_pool(), expand_media_path() should only free the pointer allocated by efi_dp_from_file() function.
include/config_distro_bootcmd.h | 14 +-------- include/efi_default_filename.h | 26 +++++++++++++++++ lib/efi_loader/efi_bootmgr.c | 50 ++++++++++++++++++++++++++++++++- 3 files changed, 76 insertions(+), 14 deletions(-) create mode 100644 include/efi_default_filename.h
diff --git a/include/config_distro_bootcmd.h b/include/config_distro_bootcmd.h index 2f90929178..ef2c9f330e 100644 --- a/include/config_distro_bootcmd.h +++ b/include/config_distro_bootcmd.h @@ -91,19 +91,7 @@ #endif
#ifdef CONFIG_EFI_LOADER -#if defined(CONFIG_ARM64) -#define BOOTEFI_NAME "bootaa64.efi" -#elif defined(CONFIG_ARM) -#define BOOTEFI_NAME "bootarm.efi" -#elif defined(CONFIG_X86_RUN_32BIT) -#define BOOTEFI_NAME "bootia32.efi" -#elif defined(CONFIG_X86_RUN_64BIT) -#define BOOTEFI_NAME "bootx64.efi" -#elif defined(CONFIG_ARCH_RV32I) -#define BOOTEFI_NAME "bootriscv32.efi" -#elif defined(CONFIG_ARCH_RV64I) -#define BOOTEFI_NAME "bootriscv64.efi" -#endif +#include <efi_default_filename.h> #endif
#ifdef BOOTEFI_NAME diff --git a/include/efi_default_filename.h b/include/efi_default_filename.h new file mode 100644 index 0000000000..de030d2692 --- /dev/null +++ b/include/efi_default_filename.h @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * Default boot file name when none is present in the FilePath. + * + * Copyright (c) 2022, Linaro Limited + */ +#ifndef _EFI_DEFAULT_FILENAME_H +#define _EFI_DEFAULT_FILENAME_H + +#if defined(CONFIG_ARM64) +#define BOOTEFI_NAME "BOOTAA64.EFI" +#elif defined(CONFIG_ARM) +#define BOOTEFI_NAME "BOOTARM.EFI" +#elif defined(CONFIG_X86_64) +#define BOOTEFI_NAME "BOOTX64.EFI" +#elif defined(CONFIG_X86) +#define BOOTEFI_NAME "BOOTIA32.EFI" +#elif defined(CONFIG_ARCH_RV32I) +#define BOOTEFI_NAME "BOOTRISCV32.EFI" +#elif defined(CONFIG_ARCH_RV64I) +#define BOOTEFI_NAME "BOOTRISCV64.EFI" +#else +#error Unsupported UEFI architecture +#endif + +#endif diff --git a/lib/efi_loader/efi_bootmgr.c b/lib/efi_loader/efi_bootmgr.c index 8c04ecbdc8..22a4302aac 100644 --- a/lib/efi_loader/efi_bootmgr.c +++ b/lib/efi_loader/efi_bootmgr.c @@ -11,6 +11,7 @@ #include <charset.h> #include <log.h> #include <malloc.h> +#include <efi_default_filename.h> #include <efi_loader.h> #include <efi_variable.h> #include <asm/unaligned.h> @@ -30,6 +31,50 @@ static const struct efi_runtime_services *rs; * should do normal or recovery boot. */
+/** + * expand_media_path() - expand a device path for default file name + * @device_path: device path to check against + * + * If @device_path is a media or disk partition which houses a file + * system, this function returns a full device path which contains + * an architecture-specific default file name for removable media. + * + * Return: a newly allocated device path + */ +static +struct efi_device_path *expand_media_path(struct efi_device_path *device_path) +{ + struct efi_device_path *dp, *full_path; + efi_handle_t handle; + efi_status_t ret; + + if (!device_path) + return NULL; + + /* + * If device_path is a (removable) media or partition which provides + * simple file system protocol, append a default file name to support + * booting from removable media. + */ + dp = device_path; + ret = efi_locate_device_path(&efi_simple_file_system_protocol_guid, + &dp, &handle); + if (ret == EFI_SUCCESS) { + if (dp->type == DEVICE_PATH_TYPE_END) { + dp = efi_dp_from_file(NULL, 0, + "/EFI/BOOT/" BOOTEFI_NAME); + full_path = efi_dp_append(device_path, dp); + efi_free_pool(dp); + } else { + full_path = efi_dp_dup(device_path); + } + } else { + full_path = efi_dp_dup(device_path); + } + + return full_path; +} + /** * try_load_entry() - try to load image for boot option * @@ -68,13 +113,16 @@ static efi_status_t try_load_entry(u16 n, efi_handle_t *handle, }
if (lo.attributes & LOAD_OPTION_ACTIVE) { + struct efi_device_path *file_path; u32 attributes;
log_debug("%s: trying to load "%ls" from %pD\n", __func__, lo.label, lo.file_path);
- ret = EFI_CALL(efi_load_image(true, efi_root, lo.file_path, + file_path = expand_media_path(lo.file_path); + ret = EFI_CALL(efi_load_image(true, efi_root, file_path, NULL, 0, handle)); + efi_free_pool(file_path); if (ret != EFI_SUCCESS) { log_warning("Loading %ls '%ls' failed\n", varname, lo.label);