| /* SPDX-License-Identifier: GPL-2.0-only */ |
| |
| #include <inttypes.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| |
| #include "elfparsing.h" |
| #include "common.h" |
| #include "cbfs.h" |
| #include "rmodule.h" |
| |
| /* Checks if program segment contains the ignored section */ |
| static int is_phdr_ignored(Elf64_Phdr *phdr, Elf64_Shdr *shdr) |
| { |
| /* If no ignored section, return false. */ |
| if (shdr == NULL) |
| return 0; |
| |
| Elf64_Addr sh_start = shdr->sh_addr; |
| Elf64_Addr sh_end = shdr->sh_addr + shdr->sh_size; |
| Elf64_Addr ph_start = phdr->p_vaddr; |
| Elf64_Addr ph_end = phdr->p_vaddr + phdr->p_memsz; |
| |
| /* Return true only if section occupies whole of segment. */ |
| if ((sh_start == ph_start) && (sh_end == ph_end)) { |
| DEBUG("Ignoring program segment at 0x%" PRIx64 "\n", ph_start); |
| return 1; |
| } |
| |
| /* If shdr intersects phdr at all, its a conflict */ |
| if (((sh_start >= ph_start) && (sh_start <= ph_end)) || |
| ((sh_end >= ph_start) && (sh_end <= ph_end))) { |
| ERROR("Conflicting sections in segment\n"); |
| exit(1); |
| } |
| |
| /* Program header doesn't need to be ignored. */ |
| return 0; |
| } |
| |
| /* Find section header based on ignored section name */ |
| static Elf64_Shdr *find_ignored_section_header(struct parsed_elf *pelf, |
| const char *ignore_section) |
| { |
| int i; |
| const char *shstrtab; |
| |
| /* No section needs to be ignored */ |
| if (ignore_section == NULL) |
| return NULL; |
| |
| DEBUG("Section to be ignored: %s\n", ignore_section); |
| |
| /* Get pointer to string table */ |
| shstrtab = buffer_get(pelf->strtabs[pelf->ehdr.e_shstrndx]); |
| |
| for (i = 0; i < pelf->ehdr.e_shnum; i++) { |
| Elf64_Shdr *shdr; |
| const char *section_name; |
| |
| shdr = &pelf->shdr[i]; |
| section_name = &shstrtab[shdr->sh_name]; |
| |
| /* If section name matches ignored string, return shdr */ |
| if (strcmp(section_name, ignore_section) == 0) |
| return shdr; |
| } |
| |
| /* No section matches ignore string */ |
| return NULL; |
| } |
| |
| static int fill_cbfs_stageheader(struct cbfs_file_attr_stageheader *stageheader, |
| uint64_t entry, uint64_t loadaddr, |
| uint32_t memsize) |
| { |
| if (entry - loadaddr >= memsize) { |
| ERROR("stage entry point out of bounds!\n"); |
| return -1; |
| } |
| |
| stageheader->loadaddr = htonll(loadaddr); |
| stageheader->memlen = htonl(memsize); |
| stageheader->entry_offset = htonl(entry - loadaddr); |
| |
| return 0; |
| } |
| |
| /* returns size of result, or -1 if error. |
| * Note that, with the new code, this function |
| * works for all elf files, not just the restricted set. |
| */ |
| int parse_elf_to_stage(const struct buffer *input, struct buffer *output, |
| const char *ignore_section, |
| struct cbfs_file_attr_stageheader *stageheader) |
| { |
| struct parsed_elf pelf; |
| Elf64_Phdr *phdr; |
| Elf64_Ehdr *ehdr; |
| Elf64_Shdr *shdr_ignored; |
| Elf64_Addr virt_to_phys; |
| int ret = -1; |
| |
| int headers; |
| int i; |
| uint64_t data_start, data_end, mem_end; |
| |
| int flags = ELF_PARSE_PHDR | ELF_PARSE_SHDR | ELF_PARSE_STRTAB; |
| |
| if (parse_elf(input, &pelf, flags)) { |
| ERROR("Couldn't parse ELF\n"); |
| return -1; |
| } |
| |
| ehdr = &pelf.ehdr; |
| phdr = &pelf.phdr[0]; |
| |
| /* Find the section header corresponding to ignored-section */ |
| shdr_ignored = find_ignored_section_header(&pelf, ignore_section); |
| |
| if (ignore_section && (shdr_ignored == NULL)) |
| WARN("Ignore section not found\n"); |
| |
| headers = ehdr->e_phnum; |
| |
| /* Ignore the program header containing ignored section */ |
| for (i = 0; i < headers; i++) { |
| if (is_phdr_ignored(&phdr[i], shdr_ignored)) |
| phdr[i].p_type = PT_NULL; |
| } |
| |
| data_start = ~0; |
| data_end = 0; |
| mem_end = 0; |
| virt_to_phys = 0; |
| |
| for (i = 0; i < headers; i++) { |
| uint64_t start, mend, rend; |
| |
| if (phdr[i].p_type != PT_LOAD) |
| continue; |
| |
| /* Empty segments are never interesting */ |
| if (phdr[i].p_memsz == 0) |
| continue; |
| |
| /* BSS */ |
| |
| start = phdr[i].p_paddr; |
| |
| mend = start + phdr[i].p_memsz; |
| rend = start + phdr[i].p_filesz; |
| |
| if (start < data_start) |
| data_start = start; |
| |
| if (rend > data_end) |
| data_end = rend; |
| |
| if (mend > mem_end) |
| mem_end = mend; |
| |
| if (virt_to_phys == 0) |
| virt_to_phys = phdr[i].p_paddr - phdr[i].p_vaddr; |
| } |
| |
| if (data_end <= data_start) { |
| ERROR("data ends (%08lx) before it starts (%08lx). Make sure " |
| "the ELF file is correct and resides in ROM space.\n", |
| (unsigned long)data_end, (unsigned long)data_start); |
| exit(1); |
| } |
| |
| if (buffer_create(output, data_end - data_start, input->name) != 0) { |
| ERROR("Unable to allocate memory: %m\n"); |
| goto err; |
| } |
| memset(output->data, 0, output->size); |
| |
| /* Copy the file data into the output buffer */ |
| |
| for (i = 0; i < headers; i++) { |
| if (phdr[i].p_type != PT_LOAD) |
| continue; |
| |
| if (phdr[i].p_memsz == 0) |
| continue; |
| |
| /* A legal ELF file can have a program header with |
| * non-zero length but zero-length file size and a |
| * non-zero offset which, added together, are > than |
| * input->size (i.e. the total file size). So we need |
| * to not even test in the case that p_filesz is zero. |
| */ |
| if (!phdr[i].p_filesz) |
| continue; |
| if (input->size < (phdr[i].p_offset + phdr[i].p_filesz)){ |
| ERROR("Underflow copying out the segment." |
| "File has %zu bytes left, segment end is %zu\n", |
| input->size, (size_t)(phdr[i].p_offset + phdr[i].p_filesz)); |
| goto err; |
| } |
| memcpy(&output->data[phdr[i].p_paddr - data_start], |
| &input->data[phdr[i].p_offset], |
| phdr[i].p_filesz); |
| } |
| |
| /* coreboot expects entry point to be physical address. Thus, adjust the |
| entry point accordingly. */ |
| ret = fill_cbfs_stageheader(stageheader, ehdr->e_entry + virt_to_phys, |
| data_start, mem_end - data_start); |
| err: |
| parsed_elf_destroy(&pelf); |
| return ret; |
| } |
| |
| struct xip_context { |
| struct rmod_context rmodctx; |
| size_t ignored_section_idx; |
| Elf64_Shdr *ignored_section; |
| }; |
| |
| static int rmod_filter(struct reloc_filter *f, const Elf64_Rela *r) |
| { |
| size_t symbol_index; |
| int reloc_type; |
| struct parsed_elf *pelf; |
| Elf64_Sym *sym; |
| struct xip_context *xipctx; |
| |
| xipctx = f->context; |
| pelf = &xipctx->rmodctx.pelf; |
| |
| /* Allow everything through if there isn't an ignored section. */ |
| if (xipctx->ignored_section == NULL) |
| return 1; |
| |
| reloc_type = ELF64_R_TYPE(r->r_info); |
| symbol_index = ELF64_R_SYM(r->r_info); |
| sym = &pelf->syms[symbol_index]; |
| |
| /* Nothing to filter. Relocation is not being applied to the |
| * ignored section. */ |
| if (sym->st_shndx != xipctx->ignored_section_idx) |
| return 1; |
| |
| /* If there is any relocation to the ignored section that isn't |
| * absolute fail as current assumptions are that all relocations |
| * are absolute. */ |
| if ((reloc_type != R_386_32) && |
| (reloc_type != R_AMD64_64) && |
| (reloc_type != R_AMD64_32)) { |
| ERROR("Invalid reloc to ignored section: %x\n", reloc_type); |
| return -1; |
| } |
| |
| /* Relocation referencing ignored section. Don't emit it. */ |
| return 0; |
| } |
| |
| int parse_elf_to_xip_stage(const struct buffer *input, struct buffer *output, |
| uint32_t location, const char *ignore_section, |
| struct cbfs_file_attr_stageheader *stageheader) |
| { |
| struct xip_context xipctx; |
| struct rmod_context *rmodctx; |
| struct reloc_filter filter; |
| struct parsed_elf *pelf; |
| uint32_t adjustment; |
| struct buffer binput; |
| struct buffer boutput; |
| Elf64_Xword i; |
| int ret = -1; |
| |
| xipctx.ignored_section_idx = 0; |
| rmodctx = &xipctx.rmodctx; |
| pelf = &rmodctx->pelf; |
| |
| if (rmodule_init(rmodctx, input)) |
| return -1; |
| |
| /* Only support x86 / x86_64 XIP currently. */ |
| if ((rmodctx->pelf.ehdr.e_machine != EM_386) && |
| (rmodctx->pelf.ehdr.e_machine != EM_X86_64)) { |
| ERROR("Only support XIP stages for x86/x86_64\n"); |
| goto out; |
| } |
| |
| xipctx.ignored_section = |
| find_ignored_section_header(pelf, ignore_section); |
| |
| if (xipctx.ignored_section != NULL) |
| xipctx.ignored_section_idx = |
| xipctx.ignored_section - pelf->shdr; |
| |
| filter.filter = rmod_filter; |
| filter.context = &xipctx; |
| |
| if (rmodule_collect_relocations(rmodctx, &filter)) |
| goto out; |
| |
| if (buffer_create(output, pelf->phdr->p_filesz, input->name) != 0) { |
| ERROR("Unable to allocate memory: %m\n"); |
| goto out; |
| } |
| buffer_clone(&boutput, output); |
| memset(buffer_get(&boutput), 0, pelf->phdr->p_filesz); |
| buffer_set_size(&boutput, 0); |
| |
| /* Single loadable segment. The entire segment moves to final |
| * location from based on virtual address of loadable segment. */ |
| adjustment = location - pelf->phdr->p_vaddr; |
| DEBUG("Relocation adjustment: %08x\n", adjustment); |
| |
| fill_cbfs_stageheader(stageheader, |
| (uint32_t)pelf->ehdr.e_entry + adjustment, |
| (uint32_t)pelf->phdr->p_vaddr + adjustment, |
| pelf->phdr->p_memsz); |
| /* Need an adjustable buffer. */ |
| buffer_clone(&binput, input); |
| buffer_seek(&binput, pelf->phdr->p_offset); |
| bputs(&boutput, buffer_get(&binput), pelf->phdr->p_filesz); |
| |
| buffer_clone(&boutput, output); |
| |
| /* Make adjustments to all the relocations within the program. */ |
| for (i = 0; i < rmodctx->nrelocs; i++) { |
| size_t reloc_offset; |
| uint32_t val; |
| struct buffer in, out; |
| |
| /* The relocations represent in-program addresses of the |
| * linked program. Obtain the offset into the program to do |
| * the adjustment. */ |
| reloc_offset = rmodctx->emitted_relocs[i] - pelf->phdr->p_vaddr; |
| |
| buffer_clone(&out, &boutput); |
| buffer_seek(&out, reloc_offset); |
| buffer_clone(&in, &out); |
| /* Appease around xdr semantics: xdr decrements buffer |
| * size when get()ing and appends to size when put()ing. */ |
| buffer_set_size(&out, 0); |
| |
| val = xdr_le.get32(&in); |
| DEBUG("reloc %zx %08x -> %08x\n", reloc_offset, val, |
| val + adjustment); |
| xdr_le.put32(&out, val + adjustment); |
| } |
| |
| ret = 0; |
| |
| out: |
| rmodule_cleanup(rmodctx); |
| return ret; |
| } |