From 4c9e2d643460d1439e417b64ed82efb02a934daf Mon Sep 17 00:00:00 2001 From: Michal Simek Date: Fri, 24 Jun 2022 14:14:59 +0200 Subject: [PATCH] tools: relocate-rela: Read rela start/end directly from ELF There is no need to pass section information via parameters. Let's read text base and rela start/end directly from elf. It will help with reading other information from ELF for others architecture. Input to relocate-rela is u-boot binary and u-boot ELF. Signed-off-by: Michal Simek Link: https://lore.kernel.org/r/ab7ae14a6e058722e8c608089729e98edf20a08d.1655299267.git.michal.simek@amd.com --- Makefile | 4 +- tools/relocate-rela.c | 181 ++++++++++++++++++++++++++++++++++++++---- 2 files changed, 168 insertions(+), 17 deletions(-) diff --git a/Makefile b/Makefile index 2270ec5c79..55c55dbb7e 100644 --- a/Makefile +++ b/Makefile @@ -925,9 +925,7 @@ ifneq ($(CONFIG_STATIC_RELA),) # $(2) is u-boot ELF, $(3) is u-boot bin, $(4) is text base quiet_cmd_static_rela = RELOC $@ cmd_static_rela = \ - start=$$($(NM) $(2) | grep __rel_dyn_start | cut -f 1 -d ' '); \ - end=$$($(NM) $(2) | grep __rel_dyn_end | cut -f 1 -d ' '); \ - tools/relocate-rela $(3) $(4) $$start $$end + tools/relocate-rela $(3) $(2) else quiet_cmd_static_rela = cmd_static_rela = diff --git a/tools/relocate-rela.c b/tools/relocate-rela.c index 67a138aa67..36065edb3f 100644 --- a/tools/relocate-rela.c +++ b/tools/relocate-rela.c @@ -20,6 +20,8 @@ #define R_AARCH64_RELATIVE 1027 #endif +static int ei_class; + static uint64_t rela_start, rela_end, text_base; static const bool debug_en; @@ -54,32 +56,183 @@ static bool supported_rela(Elf64_Rela *rela) } } -static bool read_num(const char *str, uint64_t *num) +static int decode_elf64(FILE *felf, char **argv) +{ + size_t size; + Elf64_Ehdr header; + uint64_t section_header_base, section_header_size, sh_offset, sh_size; + Elf64_Shdr *sh_table; /* Elf symbol table */ + int ret, i, machine; + char *sh_str; + + debug("64bit version\n"); + + /* Make sure we are at start */ + rewind(felf); + + size = fread(&header, 1, sizeof(header), felf); + if (size != sizeof(header)) { + fclose(felf); + return 25; + } + + machine = header.e_machine; + debug("Machine\t%d\n", machine); + + text_base = header.e_entry; + section_header_base = header.e_shoff; + section_header_size = header.e_shentsize * header.e_shnum; + + sh_table = malloc(section_header_size); + if (!sh_table) { + fprintf(stderr, "%s: Cannot allocate space for section header\n", + argv[0]); + fclose(felf); + return 26; + } + + ret = fseek(felf, section_header_base, SEEK_SET); + if (ret) { + fprintf(stderr, "%s: Can't set pointer to section header: %x/%lx\n", + argv[0], ret, section_header_base); + free(sh_table); + fclose(felf); + return 26; + } + + size = fread(sh_table, 1, section_header_size, felf); + if (size != section_header_size) { + fprintf(stderr, "%s: Can't read section header: %lx/%lx\n", + argv[0], size, section_header_size); + free(sh_table); + fclose(felf); + return 27; + } + + sh_size = sh_table[header.e_shstrndx].sh_size; + debug("e_shstrndx\t0x%08x\n", header.e_shstrndx); + debug("sh_size\t\t0x%08lx\n", sh_size); + + sh_str = malloc(sh_size); + if (!sh_str) { + fprintf(stderr, "malloc failed\n"); + free(sh_table); + fclose(felf); + return 28; + } + + /* + * Specifies the byte offset from the beginning of the file + * to the first byte in the section. + */ + sh_offset = sh_table[header.e_shstrndx].sh_offset; + + debug("sh_offset\t0x%08x\n", header.e_shnum); + + ret = fseek(felf, sh_offset, SEEK_SET); + if (ret) { + fprintf(stderr, "Setting up sh_offset failed\n"); + free(sh_str); + free(sh_table); + fclose(felf); + return 29; + } + + size = fread(sh_str, 1, sh_size, felf); + if (size != sh_size) { + fprintf(stderr, "%s: Can't read section: %lx/%lx\n", + argv[0], size, sh_size); + free(sh_str); + free(sh_table); + fclose(felf); + return 30; + } + + for (i = 0; i < header.e_shnum; i++) { + /* fprintf(stderr, "%s\n", sh_str + sh_table[i].sh_name); Debug only */ + if (!strcmp(".rela.dyn", (sh_str + sh_table[i].sh_name))) { + debug("Found section\t\".rela_dyn\"\n"); + debug(" at addr\t0x%08x\n", + (unsigned int)sh_table[i].sh_addr); + debug(" at offset\t0x%08x\n", + (unsigned int)sh_table[i].sh_offset); + debug(" of size\t0x%08x\n", + (unsigned int)sh_table[i].sh_size); + rela_start = sh_table[i].sh_addr; + rela_end = rela_start + sh_table[i].sh_size; + break; + } + } + + /* Clean up */ + free(sh_str); + free(sh_table); + fclose(felf); + + debug("text_base\t0x%08lx\n", text_base); + debug("rela_start\t0x%08lx\n", rela_start); + debug("rela_end\t0x%08lx\n", rela_end); + + if (!rela_start) + return 1; + + return 0; +} + +static int decode_elf(char **argv) { - char *endptr; - *num = strtoull(str, &endptr, 16); - return str[0] && !endptr[0]; + FILE *felf; + size_t size; + unsigned char e_ident[EI_NIDENT]; + + felf = fopen(argv[2], "r+b"); + if (!felf) { + fprintf(stderr, "%s: Cannot open %s: %s\n", + argv[0], argv[5], strerror(errno)); + return 2; + } + + size = fread(e_ident, 1, EI_NIDENT, felf); + if (size != EI_NIDENT) { + fclose(felf); + return 25; + } + + /* Check if this is really ELF file */ + if (e_ident[0] != 0x7f && + e_ident[1] != 'E' && + e_ident[2] != 'L' && + e_ident[3] != 'F') { + fclose(felf); + return 1; + } + + ei_class = e_ident[4]; + debug("EI_CLASS(1=32bit, 2=64bit) %d\n", ei_class); + + if (ei_class == 2) + return decode_elf64(felf, argv); + + return 1; } int main(int argc, char **argv) { FILE *f; - int i, num; + int i, num, ret; uint64_t file_size; - if (argc != 5) { + if (argc != 3) { fprintf(stderr, "Statically apply ELF rela relocations\n"); - fprintf(stderr, "Usage: %s " \ - " \n", argv[0]); - fprintf(stderr, "All numbers in hex.\n"); + fprintf(stderr, "Usage: %s \n", + argv[0]); return 1; } - if (!read_num(argv[2], &text_base) || - !read_num(argv[3], &rela_start) || - !read_num(argv[4], &rela_end)) { - fprintf(stderr, "%s: bad number\n", argv[0]); - return 3; + ret = decode_elf(argv); + if (ret) { + fprintf(stderr, "ELF decoding failed\n"); + return ret; } if (rela_start > rela_end || rela_start < text_base) { -- 2.39.5