diff options
Diffstat (limited to 'target')
3 files changed, 293 insertions, 0 deletions
diff --git a/target/linux/generic/files/drivers/mtd/mtdsplit/Kconfig b/target/linux/generic/files/drivers/mtd/mtdsplit/Kconfig index 0447df585c..3b7e23af33 100644 --- a/target/linux/generic/files/drivers/mtd/mtdsplit/Kconfig +++ b/target/linux/generic/files/drivers/mtd/mtdsplit/Kconfig @@ -79,3 +79,8 @@ config MTD_SPLIT_JIMAGE_FW bool "JBOOT Image based firmware partition parser" depends on MTD_SPLIT_SUPPORT select MTD_SPLIT + +config MTD_SPLIT_ELF_FW + bool "ELF loader firmware partition parser" + depends on MTD_SPLIT_SUPPORT + select MTD_SPLIT diff --git a/target/linux/generic/files/drivers/mtd/mtdsplit/Makefile b/target/linux/generic/files/drivers/mtd/mtdsplit/Makefile index d3634e78db..8671628e7c 100644 --- a/target/linux/generic/files/drivers/mtd/mtdsplit/Makefile +++ b/target/linux/generic/files/drivers/mtd/mtdsplit/Makefile @@ -12,3 +12,4 @@ obj-$(CONFIG_MTD_SPLIT_EVA_FW) += mtdsplit_eva.o obj-$(CONFIG_MTD_SPLIT_WRGG_FW) += mtdsplit_wrgg.o obj-$(CONFIG_MTD_SPLIT_MINOR_FW) += mtdsplit_minor.o obj-$(CONFIG_MTD_SPLIT_JIMAGE_FW) += mtdsplit_jimage.o +obj-$(CONFIG_MTD_SPLIT_ELF_FW) += mtdsplit_elf.o diff --git a/target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_elf.c b/target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_elf.c new file mode 100644 index 0000000000..47818416f6 --- /dev/null +++ b/target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_elf.c @@ -0,0 +1,287 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * MTD splitter for ELF loader firmware partitions + * + * Copyright (C) 2020 Sander Vanheule <sander@svanheule.net> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; version 2. + * + * To parse the ELF kernel loader, a small ELF parser is used that can + * handle both ELF32 or ELF64 class loaders. The splitter assumes that the + * kernel is always located before the rootfs, whether it is embedded in the + * loader or not. + * + * The kernel image is preferably embedded inside the ELF loader, so the end + * of the loader equals the end of the kernel partition. This is due to the + * way mtd_find_rootfs_from searches for the the rootfs: + * - if the kernel image is embedded in the loader, the appended rootfs may + * follow the loader immediately, within the same erase block. + * - if the kernel image is not embedded in the loader, but placed at some + * offset behind the loader (OKLI-style loader), the rootfs must be + * aligned to an erase-block after the loader and kernel image. + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/mtd/mtd.h> +#include <linux/mtd/partitions.h> +#include <linux/of.h> +#include <linux/byteorder/generic.h> + +#include "mtdsplit.h" + +#define ELF_NR_PARTS 2 + +#define ELF_MAGIC 0x7f454c46 /* 0x7f E L F */ +#define ELF_CLASS_32 1 +#define ELF_CLASS_64 2 + +struct elf_header_ident { + uint32_t magic; + uint8_t class; + uint8_t data; + uint8_t version; + uint8_t osabi; + uint8_t abiversion; + uint8_t pad[7]; +}; + +struct elf_header_32 { + uint16_t type; + uint16_t machine; + uint32_t version; + uint32_t entry; + uint32_t phoff; + uint32_t shoff; + uint32_t flags; + uint16_t ehsize; + uint16_t phentsize; + uint16_t phnum; + uint16_t shentsize; + uint16_t shnum; + uint16_t shstrndx; +}; + +struct elf_header_64 { + uint16_t type; + uint16_t machine; + uint32_t version; + uint64_t entry; + uint64_t phoff; + uint64_t shoff; + uint32_t flags; + uint16_t ehsize; + uint16_t phentsize; + uint16_t phnum; + uint16_t shentsize; + uint16_t shnum; + uint16_t shstrndx; +}; + +struct elf_header { + struct elf_header_ident ident; + union { + struct elf_header_32 elf32; + struct elf_header_64 elf64; + }; +}; + +struct elf_program_header_32 { + uint32_t type; + uint32_t offset; + uint32_t vaddr; + uint32_t paddr; + uint32_t filesize; + uint32_t memsize; + uint32_t flags; +}; + +struct elf_program_header_64 { + uint32_t type; + uint32_t flags; + uint64_t offset; + uint64_t vaddr; + uint64_t paddr; + uint64_t filesize; + uint64_t memsize; +}; + + +static int mtdsplit_elf_read_mtd(struct mtd_info *mtd, size_t offset, + uint8_t *dst, size_t len) +{ + size_t retlen; + int ret; + + ret = mtd_read(mtd, offset, len, &retlen, dst); + if (ret) { + pr_debug("read error in \"%s\"\n", mtd->name); + return ret; + } + + if (retlen != len) { + pr_debug("short read in \"%s\"\n", mtd->name); + return -EIO; + } + + return 0; +} + +static int elf32_determine_size(struct mtd_info *mtd, struct elf_header *hdr, + size_t *size) +{ + struct elf_header_32 *hdr32 = &(hdr->elf32); + int err; + size_t section_end, ph_table_end, ph_entry; + struct elf_program_header_32 ph; + + *size = 0; + + if (hdr32->shoff > 0) { + *size = hdr32->shoff + hdr32->shentsize * hdr32->shnum; + return 0; + } + + ph_entry = hdr32->phoff; + ph_table_end = hdr32->phoff + hdr32->phentsize * hdr32->phnum; + + while (ph_entry < ph_table_end) { + err = mtdsplit_elf_read_mtd(mtd, ph_entry, (uint8_t *)(&ph), + sizeof(ph)); + if (err) + return err; + + section_end = ph.offset + ph.filesize; + if (section_end > *size) + *size = section_end; + + ph_entry += hdr32->phentsize; + } + + return 0; +} + +static int elf64_determine_size(struct mtd_info *mtd, struct elf_header *hdr, + size_t *size) +{ + struct elf_header_64 *hdr64 = &(hdr->elf64); + int err; + size_t section_end, ph_table_end, ph_entry; + struct elf_program_header_64 ph; + + *size = 0; + + if (hdr64->shoff > 0) { + *size = hdr64->shoff + hdr64->shentsize * hdr64->shnum; + return 0; + } + + ph_entry = hdr64->phoff; + ph_table_end = hdr64->phoff + hdr64->phentsize * hdr64->phnum; + + while (ph_entry < ph_table_end) { + err = mtdsplit_elf_read_mtd(mtd, ph_entry, (uint8_t *)(&ph), + sizeof(ph)); + if (err) + return err; + + section_end = ph.offset + ph.filesize; + if (section_end > *size) + *size = section_end; + + ph_entry += hdr64->phentsize; + } + + return 0; +} + +static int mtdsplit_parse_elf(struct mtd_info *mtd, + const struct mtd_partition **pparts, + struct mtd_part_parser_data *data) +{ + struct elf_header hdr; + size_t loader_size, rootfs_offset; + enum mtdsplit_part_type type; + struct mtd_partition *parts; + int err; + + err = mtdsplit_elf_read_mtd(mtd, 0, (uint8_t *)&hdr, sizeof(hdr)); + if (err) + return err; + + if (be32_to_cpu(hdr.ident.magic) != ELF_MAGIC) { + pr_debug("invalid ELF magic %08x\n", + be32_to_cpu(hdr.ident.magic)); + return -EINVAL; + } + + switch (hdr.ident.class) { + case ELF_CLASS_32: + err = elf32_determine_size(mtd, &hdr, &loader_size); + break; + case ELF_CLASS_64: + err = elf64_determine_size(mtd, &hdr, &loader_size); + break; + default: + pr_debug("invalid ELF class %i\n", hdr.ident.class); + err = -EINVAL; + } + + if (err) + return err; + + err = mtd_find_rootfs_from(mtd, loader_size, mtd->size, + &rootfs_offset, &type); + if (err) + return err; + + if (rootfs_offset == mtd->size) { + pr_debug("no rootfs found in \"%s\"\n", mtd->name); + return -ENODEV; + } + + parts = kzalloc(ELF_NR_PARTS * sizeof(*parts), GFP_KERNEL); + if (!parts) + return -ENOMEM; + + parts[0].name = KERNEL_PART_NAME; + parts[0].offset = 0; + parts[0].size = rootfs_offset; + + if (type == MTDSPLIT_PART_TYPE_UBI) + parts[1].name = UBI_PART_NAME; + else + parts[1].name = ROOTFS_PART_NAME; + parts[1].offset = rootfs_offset; + parts[1].size = mtd->size - rootfs_offset; + + *pparts = parts; + return ELF_NR_PARTS; +} + +static const struct of_device_id mtdsplit_elf_of_match_table[] = { + { .compatible = "openwrt,elf" }, + {}, +}; +MODULE_DEVICE_TABLE(of, mtdsplit_elf_of_match_table); + +static struct mtd_part_parser mtdsplit_elf_parser = { + .owner = THIS_MODULE, + .name = "elf-loader-fw", + .of_match_table = mtdsplit_elf_of_match_table, + .parse_fn = mtdsplit_parse_elf, + .type = MTD_PARSER_TYPE_FIRMWARE, +}; + +static int __init mtdsplit_elf_init(void) +{ + register_mtd_parser(&mtdsplit_elf_parser); + + return 0; +} + +subsys_initcall(mtdsplit_elf_init); |