diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 6a0cc524882dbee2a277eb7e88700968344d5728..883da0abf7790c3ef8b01fe0e39688a4531cd5ac 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -67,7 +67,7 @@ config X86 select ARCH_HAS_FILTER_PGPROT select ARCH_HAS_FORTIFY_SOURCE select ARCH_HAS_GCOV_PROFILE_ALL - select ARCH_HAS_KCOV if X86_64 + select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION select ARCH_HAS_MEM_ENCRYPT select ARCH_HAS_MEMBARRIER_SYNC_CORE select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE diff --git a/tools/objtool/arch.h b/tools/objtool/arch.h index d0969a9328c2d85484ac8c86135fbf3a0c64550d..2e2ce089b0e9e886c731f07dbbfa5c94bf7a1a40 100644 --- a/tools/objtool/arch.h +++ b/tools/objtool/arch.h @@ -84,4 +84,6 @@ unsigned long arch_jump_destination(struct instruction *insn); unsigned long arch_dest_reloc_offset(int addend); +const char *arch_nop_insn(int len); + #endif /* _ARCH_H */ diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c index fe83d4c928251fe16e9e687851b5dd1a747128af..1967370440b30136ac9947789a510ec41f023b34 100644 --- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -565,3 +565,21 @@ void arch_initial_func_cfi_state(struct cfi_init_state *state) state->regs[16].base = CFI_CFA; state->regs[16].offset = -8; } + +const char *arch_nop_insn(int len) +{ + static const char nops[5][5] = { + /* 1 */ { 0x90 }, + /* 2 */ { 0x66, 0x90 }, + /* 3 */ { 0x0f, 0x1f, 0x00 }, + /* 4 */ { 0x0f, 0x1f, 0x40, 0x00 }, + /* 5 */ { 0x0f, 0x1f, 0x44, 0x00, 0x00 }, + }; + + if (len < 1 || len > 5) { + WARN("invalid NOP size: %d\n", len); + return NULL; + } + + return nops[len-1]; +} diff --git a/tools/objtool/arch/x86/include/arch_elf.h b/tools/objtool/arch/x86/include/arch_elf.h new file mode 100644 index 0000000000000000000000000000000000000000..69cc4264b28a85d7f4599c479f42d046de47eb20 --- /dev/null +++ b/tools/objtool/arch/x86/include/arch_elf.h @@ -0,0 +1,6 @@ +#ifndef _OBJTOOL_ARCH_ELF +#define _OBJTOOL_ARCH_ELF + +#define R_NONE R_X86_64_NONE + +#endif /* _OBJTOOL_ARCH_ELF */ diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 559c1baf9fc51a721018701ca13ba1adf6e21529..a2313ecce6d18304535bd4a6d15fa40ba88153ed 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -12,6 +12,7 @@ #include "check.h" #include "special.h" #include "warn.h" +#include "arch_elf.h" #include #include @@ -765,6 +766,24 @@ static int add_call_destinations(struct objtool_file *file) } else insn->call_dest = reloc->sym; + /* + * Many compilers cannot disable KCOV with a function attribute + * so they need a little help, NOP out any KCOV calls from noinstr + * text. + */ + if (insn->sec->noinstr && + !strncmp(insn->call_dest->name, "__sanitizer_cov_", 16)) { + if (reloc) { + reloc->type = R_NONE; + elf_write_reloc(file->elf, reloc); + } + + elf_write_insn(file->elf, insn->sec, + insn->offset, insn->len, + arch_nop_insn(insn->len)); + insn->type = INSN_NOP; + } + /* * Whatever stack impact regular CALLs have, should be undone * by the RETURN of the called function. @@ -2740,7 +2759,7 @@ int check(const char *_objname, bool orc) objname = _objname; - file.elf = elf_open_read(objname, orc ? O_RDWR : O_RDONLY); + file.elf = elf_open_read(objname, O_RDWR); if (!file.elf) return 1; @@ -2801,7 +2820,9 @@ int check(const char *_objname, bool orc) ret = create_orc_sections(&file); if (ret < 0) goto out; + } + if (file.elf->changed) { ret = elf_write(file.elf); if (ret < 0) goto out; diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c index 95d86bcb95122b4f1deb6bcaa6576af791d5f8e9..3ddbd66f1a37611dd0021c8017755a814025f34a 100644 --- a/tools/objtool/elf.c +++ b/tools/objtool/elf.c @@ -563,8 +563,10 @@ static int read_relocs(struct elf *elf) break; default: return -1; } - reloc->sym = find_symbol_by_index(elf, symndx); + reloc->sec = sec; + reloc->idx = i; + reloc->sym = find_symbol_by_index(elf, symndx); if (!reloc->sym) { WARN("can't find reloc entry symbol %d for %s", symndx, sec->name); @@ -747,6 +749,8 @@ struct section *elf_create_section(struct elf *elf, const char *name, elf_hash_add(elf->section_hash, &sec->hash, sec->idx); elf_hash_add(elf->section_name_hash, &sec->name_hash, str_hash(sec->name)); + elf->changed = true; + return sec; } @@ -880,11 +884,14 @@ static int elf_rebuild_rela_reloc_section(struct section *sec, int nr) return 0; } -int elf_rebuild_reloc_section(struct section *sec) +int elf_rebuild_reloc_section(struct elf *elf, struct section *sec) { struct reloc *reloc; int nr; + sec->changed = true; + elf->changed = true; + nr = 0; list_for_each_entry(reloc, &sec->reloc_list, list) nr++; @@ -896,7 +903,54 @@ int elf_rebuild_reloc_section(struct section *sec) } } -int elf_write(const struct elf *elf) +int elf_write_insn(struct elf *elf, struct section *sec, + unsigned long offset, unsigned int len, + const char *insn) +{ + Elf_Data *data = sec->data; + + if (data->d_type != ELF_T_BYTE || data->d_off) { + WARN("write to unexpected data for section: %s", sec->name); + return -1; + } + + memcpy(data->d_buf + offset, insn, len); + elf_flagdata(data, ELF_C_SET, ELF_F_DIRTY); + + elf->changed = true; + + return 0; +} + +int elf_write_reloc(struct elf *elf, struct reloc *reloc) +{ + struct section *sec = reloc->sec; + + if (sec->sh.sh_type == SHT_REL) { + reloc->rel.r_info = GELF_R_INFO(reloc->sym->idx, reloc->type); + reloc->rel.r_offset = reloc->offset; + + if (!gelf_update_rel(sec->data, reloc->idx, &reloc->rel)) { + WARN_ELF("gelf_update_rel"); + return -1; + } + } else { + reloc->rela.r_info = GELF_R_INFO(reloc->sym->idx, reloc->type); + reloc->rela.r_addend = reloc->addend; + reloc->rela.r_offset = reloc->offset; + + if (!gelf_update_rela(sec->data, reloc->idx, &reloc->rela)) { + WARN_ELF("gelf_update_rela"); + return -1; + } + } + + elf->changed = true; + + return 0; +} + +int elf_write(struct elf *elf) { struct section *sec; Elf_Scn *s; @@ -913,6 +967,8 @@ int elf_write(const struct elf *elf) WARN_ELF("gelf_update_shdr"); return -1; } + + sec->changed = false; } } @@ -925,6 +981,8 @@ int elf_write(const struct elf *elf) return -1; } + elf->changed = false; + return 0; } diff --git a/tools/objtool/elf.h b/tools/objtool/elf.h index 78a2db23b8b6fbd64a6512315caf08e07c7d2c9d..6cc80a0751668546c7dce140967c5b31181f9108 100644 --- a/tools/objtool/elf.h +++ b/tools/objtool/elf.h @@ -67,9 +67,10 @@ struct reloc { }; struct section *sec; struct symbol *sym; - unsigned int type; unsigned long offset; + unsigned int type; int addend; + int idx; bool jump_table_start; }; @@ -79,6 +80,7 @@ struct elf { Elf *elf; GElf_Ehdr ehdr; int fd; + bool changed; char *name; struct list_head sections; DECLARE_HASHTABLE(symbol_hash, ELF_HASH_BITS); @@ -121,7 +123,11 @@ struct elf *elf_open_read(const char *name, int flags); struct section *elf_create_section(struct elf *elf, const char *name, size_t entsize, int nr); struct section *elf_create_reloc_section(struct elf *elf, struct section *base, int reltype); void elf_add_reloc(struct elf *elf, struct reloc *reloc); -int elf_write(const struct elf *elf); +int elf_write_insn(struct elf *elf, struct section *sec, + unsigned long offset, unsigned int len, + const char *insn); +int elf_write_reloc(struct elf *elf, struct reloc *reloc); +int elf_write(struct elf *elf); void elf_close(struct elf *elf); struct section *find_section_by_name(const struct elf *elf, const char *name); @@ -133,7 +139,7 @@ struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, uns struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec, unsigned long offset, unsigned int len); struct symbol *find_func_containing(struct section *sec, unsigned long offset); -int elf_rebuild_reloc_section(struct section *sec); +int elf_rebuild_reloc_section(struct elf *elf, struct section *sec); #define for_each_sec(file, sec) \ list_for_each_entry(sec, &file->elf->sections, list) diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c index 75e08cf0709b47975b0eadefe844bf3940eb0c27..968f55e6dd94d45bdcb7c8abcf1f5748f5ad0f81 100644 --- a/tools/objtool/orc_gen.c +++ b/tools/objtool/orc_gen.c @@ -222,7 +222,7 @@ int create_orc_sections(struct objtool_file *file) } } - if (elf_rebuild_reloc_section(ip_relocsec)) + if (elf_rebuild_reloc_section(file->elf, ip_relocsec)) return -1; return 0;