From f892b7d480eec809a5dfbd6e65742b3f3155e50e Mon Sep 17 00:00:00 2001 From: Atsushi Nemoto Date: Thu, 17 May 2007 01:14:38 +0900 Subject: [PATCH] kbuild: make better section mismatch reports on i386, arm and mips On i386, ARM and MIPS, warn_sec_mismatch() sometimes fails to show usefull symbol name. This is because empty 'refsym' due to 0 r_addend value. This patch is to adjust r_addend value, consulting with apply_relocate() routine in kernel code. Without this patch: MODPOST vmlinux WARNING: init/built-in.o - Section mismatch: reference to .init.text: from .text between 'rest_init' (at offset 0xf4) and 'try_name' WARNING: mm/built-in.o - Section mismatch: reference to .init.text: from .text between 'kmem_cache_create' (at offset 0x18a39) and 'cache_reap' WARNING: mm/built-in.o - Section mismatch: reference to .init.text: from .text between 'kmem_cache_create' (at offset 0x18a6b) and 'cache_reap' With this patch: MODPOST vmlinux WARNING: mm/built-in.o - Section mismatch: reference to .init.text:set_up_list3s from .text between 'kmem_cache_create' (at offset 0x18a39) and 'cache_reap' WARNING: mm/built-in.o - Section mismatch: reference to .init.text:set_up_list3s from .text between 'kmem_cache_create' (at offset 0x18a6b) and 'cache_reap' Now modpost can detect "kernel_init" name (and whitelist it) and show "set_up_list3s" name. Signed-off-by: Atsushi Nemoto Signed-off-by: Sam Ravnborg --- scripts/mod/modpost.c | 79 +++++++++++++++++++++++++++++++++++++++++++ scripts/mod/modpost.h | 3 ++ 2 files changed, 82 insertions(+) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 2fcdbc7a1e..ce7e0d17ba 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -384,6 +384,7 @@ static int parse_elf(struct elf_info *info, const char *filename) sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size); sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link); sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name); + sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info); } /* Find symbol table. */ for (i = 1; i < hdr->e_shnum; i++) { @@ -773,6 +774,8 @@ static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf_Addr addr, for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { if (sym->st_shndx != relsym->st_shndx) continue; + if (ELF_ST_TYPE(sym->st_info) == STT_SECTION) + continue; if (sym->st_value == addr) return sym; } @@ -910,6 +913,68 @@ static void warn_sec_mismatch(const char *modname, const char *fromsec, } } +static void addend_386_rel(struct elf_info *elf, int section, Elf_Rela *r) +{ + Elf_Shdr *sechdrs = elf->sechdrs; + unsigned int r_typ; + unsigned int *location; + + r_typ = ELF_R_TYPE(r->r_info); + location = (void *)elf->hdr + + sechdrs[sechdrs[section].sh_info].sh_offset + r->r_offset; + switch (r_typ) { + case R_386_32: + r->r_addend = TO_NATIVE(*location); + break; + case R_386_PC32: + r->r_addend = TO_NATIVE(*location) + 4; + break; + } +} + +static void addend_arm_rel(struct elf_info *elf, int section, Elf_Rela *r) +{ + Elf_Shdr *sechdrs = elf->sechdrs; + unsigned int r_typ; + unsigned int *location; + + r_typ = ELF_R_TYPE(r->r_info); + location = (void *)elf->hdr + + sechdrs[sechdrs[section].sh_info].sh_offset + r->r_offset; + switch (r_typ) { + case R_ARM_ABS32: + r->r_addend = TO_NATIVE(*location); + break; + case R_ARM_PC24: + r->r_addend = ((TO_NATIVE(*location) & 0x00ffffff) << 2) + 8; + break; + } +} + +static int addend_mips_rel(struct elf_info *elf, int section, Elf_Rela *r) +{ + Elf_Shdr *sechdrs = elf->sechdrs; + unsigned int r_typ; + unsigned int *location; + unsigned int inst; + + r_typ = ELF_R_TYPE(r->r_info); + if (r_typ == R_MIPS_HI16) + return 1; /* skip this */ + location = (void *)elf->hdr + + sechdrs[sechdrs[section].sh_info].sh_offset + r->r_offset; + inst = TO_NATIVE(*location); + switch (r_typ) { + case R_MIPS_LO16: + r->r_addend = ((inst & 0xffff) ^ 0x8000) - 0x8000; + break; + case R_MIPS_26: + r->r_addend = (inst & 0x03ffffff) << 2; + break; + } + return 0; +} + /** * A module includes a number of sections that are discarded * either when loaded or when used as built-in. @@ -953,8 +1018,11 @@ static void check_sec_ref(struct module *mod, const char *modname, r.r_offset = TO_NATIVE(rela->r_offset); #if KERNEL_ELFCLASS == ELFCLASS64 if (hdr->e_machine == EM_MIPS) { + unsigned int r_typ; r_sym = ELF64_MIPS_R_SYM(rela->r_info); r_sym = TO_NATIVE(r_sym); + r_typ = ELF64_MIPS_R_TYPE(rela->r_info); + r.r_info = ELF64_R_INFO(r_sym, r_typ); } else { r.r_info = TO_NATIVE(rela->r_info); r_sym = ELF_R_SYM(r.r_info); @@ -987,8 +1055,11 @@ static void check_sec_ref(struct module *mod, const char *modname, r.r_offset = TO_NATIVE(rel->r_offset); #if KERNEL_ELFCLASS == ELFCLASS64 if (hdr->e_machine == EM_MIPS) { + unsigned int r_typ; r_sym = ELF64_MIPS_R_SYM(rel->r_info); r_sym = TO_NATIVE(r_sym); + r_typ = ELF64_MIPS_R_TYPE(rel->r_info); + r.r_info = ELF64_R_INFO(r_sym, r_typ); } else { r.r_info = TO_NATIVE(rel->r_info); r_sym = ELF_R_SYM(r.r_info); @@ -998,6 +1069,14 @@ static void check_sec_ref(struct module *mod, const char *modname, r_sym = ELF_R_SYM(r.r_info); #endif r.r_addend = 0; + if (hdr->e_machine == EM_386) + addend_386_rel(elf, i, &r); + else if (hdr->e_machine == EM_ARM) + addend_arm_rel(elf, i, &r); + else if (hdr->e_machine == EM_MIPS) { + if (addend_mips_rel(elf, i, &r)) + continue; + } sym = elf->symtab_start + r_sym; /* Skip special sections */ if (sym->st_shndx >= SHN_LORESERVE) diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h index 0858caa9c0..4156dd34c5 100644 --- a/scripts/mod/modpost.h +++ b/scripts/mod/modpost.h @@ -60,6 +60,9 @@ typedef union #define ELF64_MIPS_R_SYM(i) \ ((__extension__ (_Elf64_Mips_R_Info_union)(i)).r_info_fields.r_sym) +#define ELF64_MIPS_R_TYPE(i) \ + ((__extension__ (_Elf64_Mips_R_Info_union)(i)).r_info_fields.r_type1) + #if KERNEL_ELFDATA != HOST_ELFDATA static inline void __endian(const void *src, void *dest, unsigned int size) -- 2.39.5