From 4e65ca00f3a30791752529fe9ffe8c02da104c62 Mon Sep 17 00:00:00 2001 From: AKASHI Takahiro Date: Thu, 28 Apr 2022 17:09:39 +0900 Subject: [PATCH] efi_loader: bootmgr: add booting from removable media 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 To avoid build error for sandbox, default file name "BOOTSANDBOX.efi" is defined even if it is out of scope of UEFI specification. Signed-off-by: AKASHI Takahiro Signed-off-by: Masahisa Kojima On sandbox use binary name corresponding to host architecture. Reviewed-by: Heinrich Schuchardt --- include/efi_default_filename.h | 45 ++++++++++++++++++++++++++++++ lib/efi_loader/efi_bootmgr.c | 51 +++++++++++++++++++++++++++++++++- 2 files changed, 95 insertions(+), 1 deletion(-) create mode 100644 include/efi_default_filename.h diff --git a/include/efi_default_filename.h b/include/efi_default_filename.h new file mode 100644 index 0000000000..13b9de8754 --- /dev/null +++ b/include/efi_default_filename.h @@ -0,0 +1,45 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * When a boot option does not provide a file path the EFI file to be + * booted is \EFI\BOOT\$(BOOTEFI_NAME).EFI. The architecture specific + * file name is defined in this include. + * + * Copyright (c) 2022, Heinrich Schuchardt + */ + +#ifndef _EFI_DEFAULT_FILENAME_H +#define _EFI_DEFAULT_FILENAME_H + +#include + +#undef BOOTEFI_NAME + +#if HOST_ARCH == HOST_ARCH_X86_64 +#define BOOTEFI_NAME "BOOTX64.EFI" +#endif + +#if HOST_ARCH == HOST_ARCH_X86 +#define BOOTEFI_NAME "BOOTIA32.EFI" +#endif + +#if HOST_ARCH == HOST_ARCH_AARCH64 +#define BOOTEFI_NAME "BOOTAA64.EFI" +#endif + +#if HOST_ARCH == HOST_ARCH_ARM +#define BOOTEFI_NAME "BOOTARM.EFI" +#endif + +#if HOST_ARCH == HOST_ARCH_RISCV32 +#define BOOTEFI_NAME "BOOTRISCV32.EFI" +#endif + +#if HOST_ARCH == HOST_ARCH_RISCV64 +#define BOOTEFI_NAME "BOOTRISCV64.EFI" +#endif + +#ifndef BOOTEFI_NAME +#error Unsupported UEFI architecture +#endif + +#endif diff --git a/lib/efi_loader/efi_bootmgr.c b/lib/efi_loader/efi_bootmgr.c index 52bea4d541..631a25d76e 100644 --- a/lib/efi_loader/efi_bootmgr.c +++ b/lib/efi_loader/efi_bootmgr.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include #include @@ -30,6 +31,51 @@ 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_CALL(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 * @@ -64,13 +110,16 @@ 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("trying to load \"%ls\" from %pD\n", 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);