From f1974222634010486c1692e843af0ab11304dd2c Mon Sep 17 00:00:00 2001 From: Matt Helsley Date: Fri, 29 May 2020 14:01:13 -0700 Subject: objtool: Rename rela to reloc Before supporting additional relocation types rename the relevant types and functions from "rela" to "reloc". This work be done with the following regex: sed -e 's/struct rela/struct reloc/g' \ -e 's/\([_\*]\)rela\(s\{0,1\}\)/\1reloc\2/g' \ -e 's/tmprela\(s\{0,1\}\)/tmpreloc\1/g' \ -e 's/relasec/relocsec/g' \ -e 's/rela_list/reloc_list/g' \ -e 's/rela_hash/reloc_hash/g' \ -e 's/add_rela/add_reloc/g' \ -e 's/rela->/reloc->/g' \ -e '/rela[,\.]/{ s/\([^\.>]\)rela\([\.,]\)/\1reloc\2/g ; }' \ -e 's/rela =/reloc =/g' \ -e 's/relas =/relocs =/g' \ -e 's/relas\[/relocs[/g' \ -e 's/relaname =/relocname =/g' \ -e 's/= rela\;/= reloc\;/g' \ -e 's/= relas\;/= relocs\;/g' \ -e 's/= relaname\;/= relocname\;/g' \ -e 's/, rela)/, reloc)/g' \ -e 's/\([ @]\)rela\([ "]\)/\1reloc\2/g' \ -e 's/ rela$/ reloc/g' \ -e 's/, relaname/, relocname/g' \ -e 's/sec->rela/sec->reloc/g' \ -e 's/(\(!\{0,1\}\)rela/(\1reloc/g' \ -i \ arch.h \ arch/x86/decode.c \ check.c \ check.h \ elf.c \ elf.h \ orc_gen.c \ special.c Notable exceptions which complicate the regex include gelf_* library calls and standard/expected section names which still use "rela" because they encode the type of relocation expected. Also, keep "rela" in the struct because it encodes a specific type of relocation we currently expect. It will eventually turn into a member of an anonymous union when a susequent patch adds implicit addend, or "rel", relocation support. Signed-off-by: Matt Helsley Signed-off-by: Josh Poimboeuf --- tools/objtool/check.c | 196 +++++++++++++++++++++++++------------------------- 1 file changed, 98 insertions(+), 98 deletions(-) (limited to 'tools/objtool/check.c') diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 63d65a702900..28ce311ea90c 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -352,7 +352,7 @@ static struct instruction *find_last_insn(struct objtool_file *file, static int add_dead_ends(struct objtool_file *file) { struct section *sec; - struct rela *rela; + struct reloc *reloc; struct instruction *insn; /* @@ -370,24 +370,24 @@ static int add_dead_ends(struct objtool_file *file) if (!sec) goto reachable; - list_for_each_entry(rela, &sec->rela_list, list) { - if (rela->sym->type != STT_SECTION) { + list_for_each_entry(reloc, &sec->reloc_list, list) { + if (reloc->sym->type != STT_SECTION) { WARN("unexpected relocation symbol type in %s", sec->name); return -1; } - insn = find_insn(file, rela->sym->sec, rela->addend); + insn = find_insn(file, reloc->sym->sec, reloc->addend); if (insn) insn = list_prev_entry(insn, list); - else if (rela->addend == rela->sym->sec->len) { - insn = find_last_insn(file, rela->sym->sec); + else if (reloc->addend == reloc->sym->sec->len) { + insn = find_last_insn(file, reloc->sym->sec); if (!insn) { WARN("can't find unreachable insn at %s+0x%x", - rela->sym->sec->name, rela->addend); + reloc->sym->sec->name, reloc->addend); return -1; } } else { WARN("can't find unreachable insn at %s+0x%x", - rela->sym->sec->name, rela->addend); + reloc->sym->sec->name, reloc->addend); return -1; } @@ -405,24 +405,24 @@ reachable: if (!sec) return 0; - list_for_each_entry(rela, &sec->rela_list, list) { - if (rela->sym->type != STT_SECTION) { + list_for_each_entry(reloc, &sec->reloc_list, list) { + if (reloc->sym->type != STT_SECTION) { WARN("unexpected relocation symbol type in %s", sec->name); return -1; } - insn = find_insn(file, rela->sym->sec, rela->addend); + insn = find_insn(file, reloc->sym->sec, reloc->addend); if (insn) insn = list_prev_entry(insn, list); - else if (rela->addend == rela->sym->sec->len) { - insn = find_last_insn(file, rela->sym->sec); + else if (reloc->addend == reloc->sym->sec->len) { + insn = find_last_insn(file, reloc->sym->sec); if (!insn) { WARN("can't find reachable insn at %s+0x%x", - rela->sym->sec->name, rela->addend); + reloc->sym->sec->name, reloc->addend); return -1; } } else { WARN("can't find reachable insn at %s+0x%x", - rela->sym->sec->name, rela->addend); + reloc->sym->sec->name, reloc->addend); return -1; } @@ -440,26 +440,26 @@ static void add_ignores(struct objtool_file *file) struct instruction *insn; struct section *sec; struct symbol *func; - struct rela *rela; + struct reloc *reloc; sec = find_section_by_name(file->elf, ".rela.discard.func_stack_frame_non_standard"); if (!sec) return; - list_for_each_entry(rela, &sec->rela_list, list) { - switch (rela->sym->type) { + list_for_each_entry(reloc, &sec->reloc_list, list) { + switch (reloc->sym->type) { case STT_FUNC: - func = rela->sym; + func = reloc->sym; break; case STT_SECTION: - func = find_func_by_offset(rela->sym->sec, rela->addend); + func = find_func_by_offset(reloc->sym->sec, reloc->addend); if (!func) continue; break; default: - WARN("unexpected relocation symbol type in %s: %d", sec->name, rela->sym->type); + WARN("unexpected relocation symbol type in %s: %d", sec->name, reloc->sym->type); continue; } @@ -557,20 +557,20 @@ static void add_uaccess_safe(struct objtool_file *file) static int add_ignore_alternatives(struct objtool_file *file) { struct section *sec; - struct rela *rela; + struct reloc *reloc; struct instruction *insn; sec = find_section_by_name(file->elf, ".rela.discard.ignore_alts"); if (!sec) return 0; - list_for_each_entry(rela, &sec->rela_list, list) { - if (rela->sym->type != STT_SECTION) { + list_for_each_entry(reloc, &sec->reloc_list, list) { + if (reloc->sym->type != STT_SECTION) { WARN("unexpected relocation symbol type in %s", sec->name); return -1; } - insn = find_insn(file, rela->sym->sec, rela->addend); + insn = find_insn(file, reloc->sym->sec, reloc->addend); if (!insn) { WARN("bad .discard.ignore_alts entry"); return -1; @@ -588,7 +588,7 @@ static int add_ignore_alternatives(struct objtool_file *file) static int add_jump_destinations(struct objtool_file *file) { struct instruction *insn; - struct rela *rela; + struct reloc *reloc; struct section *dest_sec; unsigned long dest_off; @@ -599,19 +599,19 @@ static int add_jump_destinations(struct objtool_file *file) if (insn->ignore || insn->offset == FAKE_JUMP_OFFSET) continue; - rela = find_rela_by_dest_range(file->elf, insn->sec, + reloc = find_reloc_by_dest_range(file->elf, insn->sec, insn->offset, insn->len); - if (!rela) { + if (!reloc) { dest_sec = insn->sec; dest_off = arch_jump_destination(insn); - } else if (rela->sym->type == STT_SECTION) { - dest_sec = rela->sym->sec; - dest_off = arch_dest_rela_offset(rela->addend); - } else if (rela->sym->sec->idx) { - dest_sec = rela->sym->sec; - dest_off = rela->sym->sym.st_value + - arch_dest_rela_offset(rela->addend); - } else if (strstr(rela->sym->name, "_indirect_thunk_")) { + } else if (reloc->sym->type == STT_SECTION) { + dest_sec = reloc->sym->sec; + dest_off = arch_dest_reloc_offset(reloc->addend); + } else if (reloc->sym->sec->idx) { + dest_sec = reloc->sym->sec; + dest_off = reloc->sym->sym.st_value + + arch_dest_reloc_offset(reloc->addend); + } else if (strstr(reloc->sym->name, "_indirect_thunk_")) { /* * Retpoline jumps are really dynamic jumps in * disguise, so convert them accordingly. @@ -625,7 +625,7 @@ static int add_jump_destinations(struct objtool_file *file) continue; } else { /* external sibling call */ - insn->call_dest = rela->sym; + insn->call_dest = reloc->sym; continue; } @@ -701,15 +701,15 @@ static int add_call_destinations(struct objtool_file *file) { struct instruction *insn; unsigned long dest_off; - struct rela *rela; + struct reloc *reloc; for_each_insn(file, insn) { if (insn->type != INSN_CALL) continue; - rela = find_rela_by_dest_range(file->elf, insn->sec, + reloc = find_reloc_by_dest_range(file->elf, insn->sec, insn->offset, insn->len); - if (!rela) { + if (!reloc) { dest_off = arch_jump_destination(insn); insn->call_dest = find_func_by_offset(insn->sec, dest_off); if (!insn->call_dest) @@ -729,19 +729,19 @@ static int add_call_destinations(struct objtool_file *file) return -1; } - } else if (rela->sym->type == STT_SECTION) { - dest_off = arch_dest_rela_offset(rela->addend); - insn->call_dest = find_func_by_offset(rela->sym->sec, + } else if (reloc->sym->type == STT_SECTION) { + dest_off = arch_dest_reloc_offset(reloc->addend); + insn->call_dest = find_func_by_offset(reloc->sym->sec, dest_off); if (!insn->call_dest) { WARN_FUNC("can't find call dest symbol at %s+0x%lx", insn->sec, insn->offset, - rela->sym->sec->name, + reloc->sym->sec->name, dest_off); return -1; } } else - insn->call_dest = rela->sym; + insn->call_dest = reloc->sym; /* * Whatever stack impact regular CALLs have, should be undone @@ -849,7 +849,7 @@ static int handle_group_alt(struct objtool_file *file, */ if ((insn->offset != special_alt->new_off || (insn->type != INSN_CALL && !is_static_jump(insn))) && - find_rela_by_dest_range(file->elf, insn->sec, insn->offset, insn->len)) { + find_reloc_by_dest_range(file->elf, insn->sec, insn->offset, insn->len)) { WARN_FUNC("unsupported relocation in alternatives section", insn->sec, insn->offset); @@ -995,34 +995,34 @@ out: } static int add_jump_table(struct objtool_file *file, struct instruction *insn, - struct rela *table) + struct reloc *table) { - struct rela *rela = table; + struct reloc *reloc = table; struct instruction *dest_insn; struct alternative *alt; struct symbol *pfunc = insn->func->pfunc; unsigned int prev_offset = 0; /* - * Each @rela is a switch table relocation which points to the target + * Each @reloc is a switch table relocation which points to the target * instruction. */ - list_for_each_entry_from(rela, &table->sec->rela_list, list) { + list_for_each_entry_from(reloc, &table->sec->reloc_list, list) { /* Check for the end of the table: */ - if (rela != table && rela->jump_table_start) + if (reloc != table && reloc->jump_table_start) break; /* Make sure the table entries are consecutive: */ - if (prev_offset && rela->offset != prev_offset + 8) + if (prev_offset && reloc->offset != prev_offset + 8) break; /* Detect function pointers from contiguous objects: */ - if (rela->sym->sec == pfunc->sec && - rela->addend == pfunc->offset) + if (reloc->sym->sec == pfunc->sec && + reloc->addend == pfunc->offset) break; - dest_insn = find_insn(file, rela->sym->sec, rela->addend); + dest_insn = find_insn(file, reloc->sym->sec, reloc->addend); if (!dest_insn) break; @@ -1038,7 +1038,7 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn, alt->insn = dest_insn; list_add_tail(&alt->list, &insn->alts); - prev_offset = rela->offset; + prev_offset = reloc->offset; } if (!prev_offset) { @@ -1093,11 +1093,11 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn, * * NOTE: RETPOLINE made it harder still to decode dynamic jumps. */ -static struct rela *find_jump_table(struct objtool_file *file, +static struct reloc *find_jump_table(struct objtool_file *file, struct symbol *func, struct instruction *insn) { - struct rela *text_rela, *table_rela; + struct reloc *text_reloc, *table_reloc; struct instruction *dest_insn, *orig_insn = insn; struct section *table_sec; unsigned long table_offset; @@ -1122,16 +1122,16 @@ static struct rela *find_jump_table(struct objtool_file *file, break; /* look for a relocation which references .rodata */ - text_rela = find_rela_by_dest_range(file->elf, insn->sec, + text_reloc = find_reloc_by_dest_range(file->elf, insn->sec, insn->offset, insn->len); - if (!text_rela || text_rela->sym->type != STT_SECTION || - !text_rela->sym->sec->rodata) + if (!text_reloc || text_reloc->sym->type != STT_SECTION || + !text_reloc->sym->sec->rodata) continue; - table_offset = text_rela->addend; - table_sec = text_rela->sym->sec; + table_offset = text_reloc->addend; + table_sec = text_reloc->sym->sec; - if (text_rela->type == R_X86_64_PC32) + if (text_reloc->type == R_X86_64_PC32) table_offset += 4; /* @@ -1148,14 +1148,14 @@ static struct rela *find_jump_table(struct objtool_file *file, continue; /* - * Each table entry has a rela associated with it. The rela + * Each table entry has a reloc associated with it. The reloc * should reference text in the same function as the original * instruction. */ - table_rela = find_rela_by_dest(file->elf, table_sec, table_offset); - if (!table_rela) + table_reloc = find_reloc_by_dest(file->elf, table_sec, table_offset); + if (!table_reloc) continue; - dest_insn = find_insn(file, table_rela->sym->sec, table_rela->addend); + dest_insn = find_insn(file, table_reloc->sym->sec, table_reloc->addend); if (!dest_insn || !dest_insn->func || dest_insn->func->pfunc != func) continue; @@ -1164,10 +1164,10 @@ static struct rela *find_jump_table(struct objtool_file *file, * indicates a rare GCC quirk/bug which can leave dead code * behind. */ - if (text_rela->type == R_X86_64_PC32) + if (text_reloc->type == R_X86_64_PC32) file->ignore_unreachables = true; - return table_rela; + return table_reloc; } return NULL; @@ -1181,7 +1181,7 @@ static void mark_func_jump_tables(struct objtool_file *file, struct symbol *func) { struct instruction *insn, *last = NULL; - struct rela *rela; + struct reloc *reloc; func_for_each_insn(file, func, insn) { if (!last) @@ -1204,10 +1204,10 @@ static void mark_func_jump_tables(struct objtool_file *file, if (insn->type != INSN_JUMP_DYNAMIC) continue; - rela = find_jump_table(file, func, insn); - if (rela) { - rela->jump_table_start = true; - insn->jump_table = rela; + reloc = find_jump_table(file, func, insn); + if (reloc) { + reloc->jump_table_start = true; + insn->jump_table = reloc; } } } @@ -1261,8 +1261,8 @@ static int add_jump_table_alts(struct objtool_file *file) static int read_unwind_hints(struct objtool_file *file) { - struct section *sec, *relasec; - struct rela *rela; + struct section *sec, *relocsec; + struct reloc *reloc; struct unwind_hint *hint; struct instruction *insn; struct cfi_reg *cfa; @@ -1272,8 +1272,8 @@ static int read_unwind_hints(struct objtool_file *file) if (!sec) return 0; - relasec = sec->rela; - if (!relasec) { + relocsec = sec->reloc; + if (!relocsec) { WARN("missing .rela.discard.unwind_hints section"); return -1; } @@ -1288,13 +1288,13 @@ static int read_unwind_hints(struct objtool_file *file) for (i = 0; i < sec->len / sizeof(struct unwind_hint); i++) { hint = (struct unwind_hint *)sec->data->d_buf + i; - rela = find_rela_by_dest(file->elf, sec, i * sizeof(*hint)); - if (!rela) { - WARN("can't find rela for unwind_hints[%d]", i); + reloc = find_reloc_by_dest(file->elf, sec, i * sizeof(*hint)); + if (!reloc) { + WARN("can't find reloc for unwind_hints[%d]", i); return -1; } - insn = find_insn(file, rela->sym->sec, rela->addend); + insn = find_insn(file, reloc->sym->sec, reloc->addend); if (!insn) { WARN("can't find insn for unwind_hints[%d]", i); return -1; @@ -1352,19 +1352,19 @@ static int read_retpoline_hints(struct objtool_file *file) { struct section *sec; struct instruction *insn; - struct rela *rela; + struct reloc *reloc; sec = find_section_by_name(file->elf, ".rela.discard.retpoline_safe"); if (!sec) return 0; - list_for_each_entry(rela, &sec->rela_list, list) { - if (rela->sym->type != STT_SECTION) { + list_for_each_entry(reloc, &sec->reloc_list, list) { + if (reloc->sym->type != STT_SECTION) { WARN("unexpected relocation symbol type in %s", sec->name); return -1; } - insn = find_insn(file, rela->sym->sec, rela->addend); + insn = find_insn(file, reloc->sym->sec, reloc->addend); if (!insn) { WARN("bad .discard.retpoline_safe entry"); return -1; @@ -1387,19 +1387,19 @@ static int read_instr_hints(struct objtool_file *file) { struct section *sec; struct instruction *insn; - struct rela *rela; + struct reloc *reloc; sec = find_section_by_name(file->elf, ".rela.discard.instr_end"); if (!sec) return 0; - list_for_each_entry(rela, &sec->rela_list, list) { - if (rela->sym->type != STT_SECTION) { + list_for_each_entry(reloc, &sec->reloc_list, list) { + if (reloc->sym->type != STT_SECTION) { WARN("unexpected relocation symbol type in %s", sec->name); return -1; } - insn = find_insn(file, rela->sym->sec, rela->addend); + insn = find_insn(file, reloc->sym->sec, reloc->addend); if (!insn) { WARN("bad .discard.instr_end entry"); return -1; @@ -1412,13 +1412,13 @@ static int read_instr_hints(struct objtool_file *file) if (!sec) return 0; - list_for_each_entry(rela, &sec->rela_list, list) { - if (rela->sym->type != STT_SECTION) { + list_for_each_entry(reloc, &sec->reloc_list, list) { + if (reloc->sym->type != STT_SECTION) { WARN("unexpected relocation symbol type in %s", sec->name); return -1; } - insn = find_insn(file, rela->sym->sec, rela->addend); + insn = find_insn(file, reloc->sym->sec, reloc->addend); if (!insn) { WARN("bad .discard.instr_begin entry"); return -1; @@ -1434,22 +1434,22 @@ static int read_intra_function_calls(struct objtool_file *file) { struct instruction *insn; struct section *sec; - struct rela *rela; + struct reloc *reloc; sec = find_section_by_name(file->elf, ".rela.discard.intra_function_calls"); if (!sec) return 0; - list_for_each_entry(rela, &sec->rela_list, list) { + list_for_each_entry(reloc, &sec->reloc_list, list) { unsigned long dest_off; - if (rela->sym->type != STT_SECTION) { + if (reloc->sym->type != STT_SECTION) { WARN("unexpected relocation symbol type in %s", sec->name); return -1; } - insn = find_insn(file, rela->sym->sec, rela->addend); + insn = find_insn(file, reloc->sym->sec, reloc->addend); if (!insn) { WARN("bad .discard.intra_function_call entry"); return -1; -- cgit v1.2.3 From 6b643a07a7e41f9e11cfbb9bba4c5c9791ac2997 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 3 Jun 2020 20:09:06 +0200 Subject: x86/entry, ubsan, objtool: Whitelist __ubsan_handle_*() The UBSAN instrumentation only inserts external CALLs when things go 'BAD', much like WARN(). So treat them similar to WARN()s for noinstr, that is: allow them, at the risk of taking the machine down, to get their message out. Suggested-by: Marco Elver Signed-off-by: Peter Zijlstra (Intel) Acked-by: Marco Elver --- include/linux/compiler_types.h | 2 +- tools/objtool/check.c | 28 +++++++++++++++++++++++++++- 2 files changed, 28 insertions(+), 2 deletions(-) (limited to 'tools/objtool/check.c') diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index 85b8d2370c24..14513e88b7e0 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -199,7 +199,7 @@ struct ftrace_likely_data { /* Section for code which can't be instrumented at all */ #define noinstr \ noinline notrace __attribute((__section__(".noinstr.text"))) \ - __no_kcsan __no_sanitize_address __no_sanitize_undefined + __no_kcsan __no_sanitize_address #endif /* __KERNEL__ */ diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 5fbb90a80d23..3e214f879ada 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -2190,10 +2190,36 @@ static inline const char *call_dest_name(struct instruction *insn) return "{dynamic}"; } +static inline bool noinstr_call_dest(struct symbol *func) +{ + /* + * We can't deal with indirect function calls at present; + * assume they're instrumented. + */ + if (!func) + return false; + + /* + * If the symbol is from a noinstr section; we good. + */ + if (func->sec->noinstr) + return true; + + /* + * The __ubsan_handle_*() calls are like WARN(), they only happen when + * something 'BAD' happened. At the risk of taking the machine down, + * let them proceed to get the message out. + */ + if (!strncmp(func->name, "__ubsan_handle_", 15)) + return true; + + return false; +} + static int validate_call(struct instruction *insn, struct insn_state *state) { if (state->noinstr && state->instr <= 0 && - (!insn->call_dest || !insn->call_dest->sec->noinstr)) { + !noinstr_call_dest(insn->call_dest)) { WARN_FUNC("call to %s() leaves .noinstr.text section", insn->sec, insn->offset, call_dest_name(insn)); return 1; -- cgit v1.2.3 From 2b10be23ac0f8e107fd575397361ddbaebc2944b Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 17 Apr 2020 23:15:00 +0200 Subject: objtool: Clean up elf_write() condition With there being multiple ways to change the ELF data, let's more concisely track modification. Signed-off-by: Peter Zijlstra (Intel) --- tools/objtool/check.c | 4 +++- tools/objtool/elf.c | 13 +++++++++++-- tools/objtool/elf.h | 5 +++-- tools/objtool/orc_gen.c | 2 +- 4 files changed, 18 insertions(+), 6 deletions(-) (limited to 'tools/objtool/check.c') diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 5fbb90a80d23..91a67db26165 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -2740,7 +2740,7 @@ 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 +2801,9 @@ 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 84225679f96d..bc6723a502c3 100644 --- a/tools/objtool/elf.c +++ b/tools/objtool/elf.c @@ -713,6 +713,8 @@ 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; } @@ -746,7 +748,7 @@ struct section *elf_create_rela_section(struct elf *elf, struct section *base) return sec; } -int elf_rebuild_rela_section(struct section *sec) +int elf_rebuild_rela_section(struct elf *elf, struct section *sec) { struct rela *rela; int nr, idx = 0, size; @@ -763,6 +765,9 @@ int elf_rebuild_rela_section(struct section *sec) return -1; } + sec->changed = true; + elf->changed = true; + sec->data->d_buf = relas; sec->data->d_size = size; @@ -779,7 +784,7 @@ int elf_rebuild_rela_section(struct section *sec) return 0; } -int elf_write(const struct elf *elf) +int elf_write(struct elf *elf) { struct section *sec; Elf_Scn *s; @@ -796,6 +801,8 @@ int elf_write(const struct elf *elf) WARN_ELF("gelf_update_shdr"); return -1; } + + sec->changed = false; } } @@ -808,6 +815,8 @@ 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 f4fe1d6ea392..aa9c64da379f 100644 --- a/tools/objtool/elf.h +++ b/tools/objtool/elf.h @@ -76,6 +76,7 @@ struct elf { Elf *elf; GElf_Ehdr ehdr; int fd; + bool changed; char *name; struct list_head sections; DECLARE_HASHTABLE(symbol_hash, ELF_HASH_BITS); @@ -118,7 +119,7 @@ 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_rela_section(struct elf *elf, struct section *base); void elf_add_rela(struct elf *elf, struct rela *rela); -int elf_write(const struct elf *elf); +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); @@ -130,7 +131,7 @@ struct rela *find_rela_by_dest(const struct elf *elf, struct section *sec, unsig struct rela *find_rela_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_rela_section(struct section *sec); +int elf_rebuild_rela_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 c9549988121a..4c37f80eb987 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_rela_section(ip_relasec)) + if (elf_rebuild_rela_section(file->elf, ip_relasec)) return -1; return 0; -- cgit v1.2.3 From 0f1441b44e823a74f3f3780902a113e07c73fbf6 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 12 Jun 2020 16:05:26 +0200 Subject: objtool: Fix noinstr vs KCOV Since many compilers cannot disable KCOV with a function attribute, help it to NOP out any __sanitizer_cov_*() calls injected in noinstr code. This turns: 12: e8 00 00 00 00 callq 17 13: R_X86_64_PLT32 __sanitizer_cov_trace_pc-0x4 into: 12: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 13: R_X86_64_NONE __sanitizer_cov_trace_pc-0x4 Just like recordmcount does. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Dmitry Vyukov --- arch/x86/Kconfig | 2 +- tools/objtool/arch.h | 2 ++ tools/objtool/arch/x86/decode.c | 18 ++++++++++++++++++ tools/objtool/arch/x86/include/arch_elf.h | 6 ++++++ tools/objtool/check.c | 19 +++++++++++++++++++ 5 files changed, 46 insertions(+), 1 deletion(-) create mode 100644 tools/objtool/arch/x86/include/arch_elf.h (limited to 'tools/objtool/check.c') diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 6a0cc524882d..883da0abf779 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 eda15a5a285e..3c5967748abb 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_rela_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 4b504fc90bbb..9872195f998b 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 000000000000..69cc4264b28a --- /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 91a67db26165..478267a072d0 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 = rela->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 (rela) { + rela->type = R_NONE; + elf_write_rela(file->elf, rela); + } + + 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. -- cgit v1.2.3 From 734d099ba644f5a92c70efa3d54d0ba2500ce162 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 17 Jun 2020 18:22:31 +0200 Subject: objtool: Don't consider vmlinux a C-file Avoids issuing C-file warnings for vmlinux. Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20200618144801.701257527@infradead.org --- tools/objtool/check.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/objtool/check.c') diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 3e214f879ada..d8eaa7dc53d5 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -2772,7 +2772,7 @@ int check(const char *_objname, bool orc) INIT_LIST_HEAD(&file.insn_list); hash_init(file.insn_hash); - file.c_file = find_section_by_name(file.elf, ".comment"); + file.c_file = !vmlinux && find_section_by_name(file.elf, ".comment"); file.ignore_unreachables = no_unreachable; file.hints = false; -- cgit v1.2.3