From 86ea7f361537f825a699e86fdc9e49be19f128d1 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Mon, 14 Nov 2022 23:27:48 +0530 Subject: objtool: Use target file class size instead of a compiled constant In order to allow using objtool on cross-built kernels, determine size of long from elf data instead of using sizeof(long) at build time. For the time being this covers only mcount. [Sathvika Vasireddy: Rename variable "size" to "addrsize" and function "elf_class_size()" to "elf_class_addrsize()", and modify create_mcount_loc_sections() function to follow reverse christmas tree format to order local variable declarations.] Tested-by: Naveen N. Rao Reviewed-by: Naveen N. Rao Acked-by: Josh Poimboeuf Acked-by: Peter Zijlstra (Intel) Signed-off-by: Christophe Leroy Signed-off-by: Sathvika Vasireddy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221114175754.1131267-11-sv@linux.ibm.com --- tools/objtool/check.c | 18 ++++++++++-------- tools/objtool/elf.c | 8 ++++++-- tools/objtool/include/objtool/elf.h | 8 ++++++++ 3 files changed, 24 insertions(+), 10 deletions(-) (limited to 'tools/objtool') diff --git a/tools/objtool/check.c b/tools/objtool/check.c index ad5dab175701..b64518c7c7b4 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -852,9 +852,9 @@ static int create_ibt_endbr_seal_sections(struct objtool_file *file) static int create_mcount_loc_sections(struct objtool_file *file) { - struct section *sec; - unsigned long *loc; + int addrsize = elf_class_addrsize(file->elf); struct instruction *insn; + struct section *sec; int idx; sec = find_section_by_name(file->elf, "__mcount_loc"); @@ -871,23 +871,25 @@ static int create_mcount_loc_sections(struct objtool_file *file) list_for_each_entry(insn, &file->mcount_loc_list, call_node) idx++; - sec = elf_create_section(file->elf, "__mcount_loc", 0, sizeof(unsigned long), idx); + sec = elf_create_section(file->elf, "__mcount_loc", 0, addrsize, idx); if (!sec) return -1; + sec->sh.sh_addralign = addrsize; + idx = 0; list_for_each_entry(insn, &file->mcount_loc_list, call_node) { + void *loc; - loc = (unsigned long *)sec->data->d_buf + idx; - memset(loc, 0, sizeof(unsigned long)); + loc = sec->data->d_buf + idx; + memset(loc, 0, addrsize); - if (elf_add_reloc_to_insn(file->elf, sec, - idx * sizeof(unsigned long), + if (elf_add_reloc_to_insn(file->elf, sec, idx, R_X86_64_64, insn->sec, insn->offset)) return -1; - idx++; + idx += addrsize; } return 0; diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c index 7e24b09b1163..33739865735b 100644 --- a/tools/objtool/elf.c +++ b/tools/objtool/elf.c @@ -1129,6 +1129,7 @@ static struct section *elf_create_rela_reloc_section(struct elf *elf, struct sec { char *relocname; struct section *sec; + int addrsize = elf_class_addrsize(elf); relocname = malloc(strlen(base->name) + strlen(".rela") + 1); if (!relocname) { @@ -1138,7 +1139,10 @@ static struct section *elf_create_rela_reloc_section(struct elf *elf, struct sec strcpy(relocname, ".rela"); strcat(relocname, base->name); - sec = elf_create_section(elf, relocname, 0, sizeof(GElf_Rela), 0); + if (addrsize == sizeof(u32)) + sec = elf_create_section(elf, relocname, 0, sizeof(Elf32_Rela), 0); + else + sec = elf_create_section(elf, relocname, 0, sizeof(GElf_Rela), 0); free(relocname); if (!sec) return NULL; @@ -1147,7 +1151,7 @@ static struct section *elf_create_rela_reloc_section(struct elf *elf, struct sec sec->base = base; sec->sh.sh_type = SHT_RELA; - sec->sh.sh_addralign = 8; + sec->sh.sh_addralign = addrsize; sec->sh.sh_link = find_section_by_name(elf, ".symtab")->idx; sec->sh.sh_info = base->idx; sec->sh.sh_flags = SHF_INFO_LINK; diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h index 16f4067b82ae..78b3aa2e546d 100644 --- a/tools/objtool/include/objtool/elf.h +++ b/tools/objtool/include/objtool/elf.h @@ -142,6 +142,14 @@ static inline bool has_multiple_files(struct elf *elf) return elf->num_files > 1; } +static inline int elf_class_addrsize(struct elf *elf) +{ + if (elf->ehdr.e_ident[EI_CLASS] == ELFCLASS32) + return sizeof(u32); + else + return sizeof(u64); +} + struct elf *elf_open_read(const char *name, int flags); struct section *elf_create_section(struct elf *elf, const char *name, unsigned int sh_flags, size_t entsize, int nr); -- cgit v1.2.3