diff options
Diffstat (limited to 'lib/efi_loader/efi_load_initrd.c')
| -rw-r--r-- | lib/efi_loader/efi_load_initrd.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/lib/efi_loader/efi_load_initrd.c b/lib/efi_loader/efi_load_initrd.c new file mode 100644 index 0000000000..574a83d7e3 --- /dev/null +++ b/lib/efi_loader/efi_load_initrd.c @@ -0,0 +1,198 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (c) 2020, Linaro Limited + */ + +#include <common.h> +#include <env.h> +#include <malloc.h> +#include <mapmem.h> +#include <dm.h> +#include <fs.h> +#include <efi_loader.h> +#include <efi_load_initrd.h> + +static const efi_guid_t efi_guid_load_file2_protocol = + EFI_LOAD_FILE2_PROTOCOL_GUID; + +static efi_status_t EFIAPI +efi_load_file2_initrd(struct efi_load_file_protocol *this, + struct efi_device_path *file_path, bool boot_policy, + efi_uintn_t *buffer_size, void *buffer); + +static const struct efi_load_file_protocol efi_lf2_protocol = { + .load_file = efi_load_file2_initrd, +}; + +/* + * Device path defined by Linux to identify the handle providing the + * EFI_LOAD_FILE2_PROTOCOL used for loading the initial ramdisk. + */ +static const struct efi_initrd_dp dp = { + .vendor = { + { + DEVICE_PATH_TYPE_MEDIA_DEVICE, + DEVICE_PATH_SUB_TYPE_VENDOR_PATH, + sizeof(dp.vendor), + }, + EFI_INITRD_MEDIA_GUID, + }, + .end = { + DEVICE_PATH_TYPE_END, + DEVICE_PATH_SUB_TYPE_END, + sizeof(dp.end), + } +}; + +/** + * get_file_size() - retrieve the size of initramfs, set efi status on error + * + * @dev: device to read from. i.e "mmc" + * @part: device partition. i.e "0:1" + * @file: name fo file + * @status: EFI exit code in case of failure + * + * Return: size of file + */ +static loff_t get_file_size(const char *dev, const char *part, const char *file, + efi_status_t *status) +{ + loff_t sz = 0; + int ret; + + ret = fs_set_blk_dev(dev, part, FS_TYPE_ANY); + if (ret) { + *status = EFI_NO_MEDIA; + goto out; + } + + ret = fs_size(file, &sz); + if (ret) { + sz = 0; + *status = EFI_NOT_FOUND; + goto out; + } + +out: + return sz; +} + +/** + * load_file2() - get information about random number generation + * + * This function implement the LoadFile2() service in order to load an initram + * disk requested by the Linux kernel stub. + * See the UEFI spec for details. + * + * @this: loadfile2 protocol instance + * @file_path: relative path of the file. "" in this case + * @boot_policy: must be false for Loadfile2 + * @buffer_size: size of allocated buffer + * @buffer: buffer to load the file + * + * Return: status code + */ +static efi_status_t EFIAPI +efi_load_file2_initrd(struct efi_load_file_protocol *this, + struct efi_device_path *file_path, bool boot_policy, + efi_uintn_t *buffer_size, void *buffer) +{ + const char *filespec = CONFIG_EFI_INITRD_FILESPEC; + efi_status_t status = EFI_NOT_FOUND; + loff_t file_sz = 0, read_sz = 0; + char *dev, *part, *file; + char *s; + int ret; + + EFI_ENTRY("%p, %p, %d, %p, %p", this, file_path, boot_policy, + buffer_size, buffer); + + s = strdup(filespec); + if (!s) + goto out; + + if (!this || this != &efi_lf2_protocol || + !buffer_size) { + status = EFI_INVALID_PARAMETER; + goto out; + } + + if (file_path->type != dp.end.type || + file_path->sub_type != dp.end.sub_type) { + status = EFI_INVALID_PARAMETER; + goto out; + } + + if (boot_policy) { + status = EFI_UNSUPPORTED; + goto out; + } + + /* expect something like 'mmc 0:1 initrd.cpio.gz' */ + dev = strsep(&s, " "); + if (!dev) + goto out; + part = strsep(&s, " "); + if (!part) + goto out; + file = strsep(&s, " "); + if (!file) + goto out; + + file_sz = get_file_size(dev, part, file, &status); + if (!file_sz) + goto out; + + if (!buffer || *buffer_size < file_sz) { + status = EFI_BUFFER_TOO_SMALL; + *buffer_size = file_sz; + } else { + ret = fs_set_blk_dev(dev, part, FS_TYPE_ANY); + if (ret) { + status = EFI_NO_MEDIA; + goto out; + } + + ret = fs_read(file, map_to_sysmem(buffer), 0, *buffer_size, + &read_sz); + if (ret || read_sz != file_sz) + goto out; + *buffer_size = read_sz; + + status = EFI_SUCCESS; + } + +out: + free(s); + return EFI_EXIT(status); +} + +/** + * efi_initrd_register() - Register a handle and loadfile2 protocol + * + * This function creates a new handle and installs a linux specific GUID + * to handle initram disk loading during boot. + * See the UEFI spec for details. + * + * Return: status code + */ +efi_status_t efi_initrd_register(void) +{ + efi_handle_t efi_initrd_handle = NULL; + efi_status_t ret; + + /* + * Set up the handle with the EFI_LOAD_FILE2_PROTOCOL which Linux may + * use to load the initial ramdisk. + */ + ret = EFI_CALL(efi_install_multiple_protocol_interfaces + (&efi_initrd_handle, + /* initramfs */ + &efi_guid_device_path, &dp, + /* LOAD_FILE2 */ + &efi_guid_load_file2_protocol, + (void *)&efi_lf2_protocol, + NULL)); + + return ret; +} |