diff options
Diffstat (limited to 'tools/objtool/check.c')
| -rw-r--r-- | tools/objtool/check.c | 645 |
1 files changed, 533 insertions, 112 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 7c33ec67c4a9..190b2f6e360a 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -5,6 +5,7 @@ #include <string.h> #include <stdlib.h> +#include <inttypes.h> #include <sys/mman.h> #include <arch/elf.h> @@ -181,6 +182,10 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func, "kunit_try_catch_throw", "xen_start_kernel", "cpu_bringup_and_idle", + "do_group_exit", + "stop_this_cpu", + "__invalid_creds", + "cpu_startup_entry", }; if (!func) @@ -259,7 +264,8 @@ static void init_cfi_state(struct cfi_state *cfi) cfi->drap_offset = -1; } -static void init_insn_state(struct insn_state *state, struct section *sec) +static void init_insn_state(struct objtool_file *file, struct insn_state *state, + struct section *sec) { memset(state, 0, sizeof(*state)); init_cfi_state(&state->cfi); @@ -269,7 +275,7 @@ static void init_insn_state(struct insn_state *state, struct section *sec) * not correctly determine insn->call_dest->sec (external symbols do * not have a section). */ - if (vmlinux && noinstr && sec) + if (opts.link && opts.noinstr && sec) state->noinstr = sec->noinstr; } @@ -335,7 +341,7 @@ static void *cfi_hash_alloc(unsigned long size) if (cfi_hash == (void *)-1L) { WARN("mmap fail cfi_hash"); cfi_hash = NULL; - } else if (stats) { + } else if (opts.stats) { printf("cfi_bits: %d\n", cfi_bits); } @@ -380,6 +386,7 @@ static int decode_instructions(struct objtool_file *file) memset(insn, 0, sizeof(*insn)); INIT_LIST_HEAD(&insn->alts); INIT_LIST_HEAD(&insn->stack_ops); + INIT_LIST_HEAD(&insn->call_node); insn->sec = sec; insn->offset = offset; @@ -392,6 +399,14 @@ static int decode_instructions(struct objtool_file *file) if (ret) goto err; + /* + * By default, "ud2" is a dead end unless otherwise + * annotated, because GCC 7 inserts it for certain + * divide-by-zero cases. + */ + if (insn->type == INSN_BUG) + insn->dead_end = true; + hash_add(file->insn_hash, &insn->hash, sec_offset_hash(sec, insn->offset)); list_add_tail(&insn->list, &file->insn_list); nr_insns++; @@ -407,12 +422,21 @@ static int decode_instructions(struct objtool_file *file) return -1; } - sym_for_each_insn(file, func, insn) + sym_for_each_insn(file, func, insn) { insn->func = func; + if (insn->type == INSN_ENDBR && list_empty(&insn->call_node)) { + if (insn->offset == insn->func->offset) { + list_add_tail(&insn->call_node, &file->endbr_list); + file->nr_endbr++; + } else { + file->nr_endbr_int++; + } + } + } } } - if (stats) + if (opts.stats) printf("nr_insns: %lu\n", nr_insns); return 0; @@ -475,7 +499,7 @@ static int init_pv_ops(struct objtool_file *file) struct symbol *sym; int idx, nr; - if (!noinstr) + if (!opts.noinstr) return 0; file->pv_ops = NULL; @@ -521,14 +545,6 @@ static int add_dead_ends(struct objtool_file *file) struct instruction *insn; /* - * By default, "ud2" is a dead end unless otherwise annotated, because - * GCC 7 inserts it for certain divide-by-zero cases. - */ - for_each_insn(file, insn) - if (insn->type == INSN_BUG) - insn->dead_end = true; - - /* * Check for manually annotated dead ends. */ sec = find_section_by_name(file->elf, ".rela.discard.unreachable"); @@ -546,12 +562,12 @@ static int add_dead_ends(struct objtool_file *file) else if (reloc->addend == reloc->sym->sec->sh.sh_size) { insn = find_last_insn(file, reloc->sym->sec); if (!insn) { - WARN("can't find unreachable insn at %s+0x%x", + WARN("can't find unreachable insn at %s+0x%" PRIx64, reloc->sym->sec->name, reloc->addend); return -1; } } else { - WARN("can't find unreachable insn at %s+0x%x", + WARN("can't find unreachable insn at %s+0x%" PRIx64, reloc->sym->sec->name, reloc->addend); return -1; } @@ -581,12 +597,12 @@ reachable: else if (reloc->addend == reloc->sym->sec->sh.sh_size) { insn = find_last_insn(file, reloc->sym->sec); if (!insn) { - WARN("can't find reachable insn at %s+0x%x", + WARN("can't find reachable insn at %s+0x%" PRIx64, reloc->sym->sec->name, reloc->addend); return -1; } } else { - WARN("can't find reachable insn at %s+0x%x", + WARN("can't find reachable insn at %s+0x%" PRIx64, reloc->sym->sec->name, reloc->addend); return -1; } @@ -654,7 +670,7 @@ static int create_static_call_sections(struct objtool_file *file) key_sym = find_symbol_by_name(file->elf, tmp); if (!key_sym) { - if (!module) { + if (!opts.module) { WARN("static_call: can't find static_call_key symbol: %s", tmp); return -1; } @@ -731,6 +747,58 @@ static int create_retpoline_sites_sections(struct objtool_file *file) return 0; } +static int create_ibt_endbr_seal_sections(struct objtool_file *file) +{ + struct instruction *insn; + struct section *sec; + int idx; + + sec = find_section_by_name(file->elf, ".ibt_endbr_seal"); + if (sec) { + WARN("file already has .ibt_endbr_seal, skipping"); + return 0; + } + + idx = 0; + list_for_each_entry(insn, &file->endbr_list, call_node) + idx++; + + if (opts.stats) { + printf("ibt: ENDBR at function start: %d\n", file->nr_endbr); + printf("ibt: ENDBR inside functions: %d\n", file->nr_endbr_int); + printf("ibt: superfluous ENDBR: %d\n", idx); + } + + if (!idx) + return 0; + + sec = elf_create_section(file->elf, ".ibt_endbr_seal", 0, + sizeof(int), idx); + if (!sec) { + WARN("elf_create_section: .ibt_endbr_seal"); + return -1; + } + + idx = 0; + list_for_each_entry(insn, &file->endbr_list, call_node) { + + int *site = (int *)sec->data->d_buf + idx; + *site = 0; + + if (elf_add_reloc_to_insn(file->elf, sec, + idx * sizeof(int), + R_X86_64_PC32, + insn->sec, insn->offset)) { + WARN("elf_add_reloc_to_insn: .ibt_endbr_seal"); + return -1; + } + + idx++; + } + + return 0; +} + static int create_mcount_loc_sections(struct objtool_file *file) { struct section *sec; @@ -962,7 +1030,7 @@ static void add_uaccess_safe(struct objtool_file *file) struct symbol *func; const char **name; - if (!uaccess) + if (!opts.uaccess) return; for (name = uaccess_safe_builtin; *name; name++) { @@ -1078,7 +1146,7 @@ static void annotate_call_site(struct objtool_file *file, * attribute so they need a little help, NOP out any such calls from * noinstr text. */ - if (insn->sec->noinstr && sym->profiling_func) { + if (opts.hack_noinstr && insn->sec->noinstr && sym->profiling_func) { if (reloc) { reloc->type = R_NONE; elf_write_reloc(file->elf, reloc); @@ -1090,10 +1158,21 @@ static void annotate_call_site(struct objtool_file *file, : arch_nop_insn(insn->len)); insn->type = sibling ? INSN_RETURN : INSN_NOP; + + if (sibling) { + /* + * We've replaced the tail-call JMP insn by two new + * insn: RET; INT3, except we only have a single struct + * insn here. Mark it retpoline_safe to avoid the SLS + * warning, instead of adding another insn. + */ + insn->retpoline_safe = true; + } + return; } - if (mcount && sym->fentry) { + if (opts.mcount && sym->fentry) { if (sibling) WARN_FUNC("Tail call to __fentry__ !?!?", insn->sec, insn->offset); @@ -1111,6 +1190,9 @@ static void annotate_call_site(struct objtool_file *file, list_add_tail(&insn->call_node, &file->mcount_loc_list); return; } + + if (!sibling && dead_end_function(file, sym)) + insn->dead_end = true; } static void add_call_dest(struct objtool_file *file, struct instruction *insn, @@ -1165,17 +1247,46 @@ static void add_retpoline_call(struct objtool_file *file, struct instruction *in annotate_call_site(file, insn, false); } + +static bool same_function(struct instruction *insn1, struct instruction *insn2) +{ + return insn1->func->pfunc == insn2->func->pfunc; +} + +static bool is_first_func_insn(struct objtool_file *file, struct instruction *insn) +{ + if (insn->offset == insn->func->offset) + return true; + + if (opts.ibt) { + struct instruction *prev = prev_insn_same_sym(file, insn); + + if (prev && prev->type == INSN_ENDBR && + insn->offset == insn->func->offset + prev->len) + return true; + } + + return false; +} + /* * Find the destination instructions for all jumps. */ static int add_jump_destinations(struct objtool_file *file) { - struct instruction *insn; + struct instruction *insn, *jump_dest; struct reloc *reloc; struct section *dest_sec; unsigned long dest_off; for_each_insn(file, insn) { + if (insn->jump_dest) { + /* + * handle_group_alt() may have previously set + * 'jump_dest' for some alternatives. + */ + continue; + } if (!is_static_jump(insn)) continue; @@ -1190,7 +1301,10 @@ static int add_jump_destinations(struct objtool_file *file) add_retpoline_call(file, insn); continue; } else if (insn->func) { - /* internal or external sibling call (with reloc) */ + /* + * External sibling call or internal sibling call with + * STT_FUNC reloc. + */ add_call_dest(file, insn, reloc->sym, true); continue; } else if (reloc->sym->sec->idx) { @@ -1202,17 +1316,8 @@ static int add_jump_destinations(struct objtool_file *file) continue; } - insn->jump_dest = find_insn(file, dest_sec, dest_off); - if (!insn->jump_dest) { - - /* - * This is a special case where an alt instruction - * jumps past the end of the section. These are - * handled later in handle_group_alt(). - */ - if (!strcmp(insn->sec->name, ".altinstr_replacement")) - continue; - + jump_dest = find_insn(file, dest_sec, dest_off); + if (!jump_dest) { WARN_FUNC("can't find jump dest instruction at %s+0x%lx", insn->sec, insn->offset, dest_sec->name, dest_off); @@ -1222,8 +1327,8 @@ static int add_jump_destinations(struct objtool_file *file) /* * Cross-function jump. */ - if (insn->func && insn->jump_dest->func && - insn->func != insn->jump_dest->func) { + if (insn->func && jump_dest->func && + insn->func != jump_dest->func) { /* * For GCC 8+, create parent/child links for any cold @@ -1241,16 +1346,22 @@ static int add_jump_destinations(struct objtool_file *file) * subfunction is through a jump table. */ if (!strstr(insn->func->name, ".cold") && - strstr(insn->jump_dest->func->name, ".cold")) { - insn->func->cfunc = insn->jump_dest->func; - insn->jump_dest->func->pfunc = insn->func; + strstr(jump_dest->func->name, ".cold")) { + insn->func->cfunc = jump_dest->func; + jump_dest->func->pfunc = insn->func; - } else if (insn->jump_dest->func->pfunc != insn->func->pfunc && - insn->jump_dest->offset == insn->jump_dest->func->offset) { - /* internal sibling call (without reloc) */ - add_call_dest(file, insn, insn->jump_dest->func, true); + } else if (!same_function(insn, jump_dest) && + is_first_func_insn(file, jump_dest)) { + /* + * Internal sibling call without reloc or with + * STT_SECTION reloc. + */ + add_call_dest(file, insn, jump_dest->func, true); + continue; } } + + insn->jump_dest = jump_dest; } return 0; @@ -1439,13 +1550,13 @@ static int handle_group_alt(struct objtool_file *file, continue; dest_off = arch_jump_destination(insn); - if (dest_off == special_alt->new_off + special_alt->new_len) + if (dest_off == special_alt->new_off + special_alt->new_len) { insn->jump_dest = next_insn_same_sec(file, last_orig_insn); - - if (!insn->jump_dest) { - WARN_FUNC("can't find alternative jump destination", - insn->sec, insn->offset); - return -1; + if (!insn->jump_dest) { + WARN_FUNC("can't find alternative jump destination", + insn->sec, insn->offset); + return -1; + } } } @@ -1483,7 +1594,7 @@ static int handle_jump_alt(struct objtool_file *file, return -1; } - if (special_alt->key_addend & 2) { + if (opts.hack_jump_label && special_alt->key_addend & 2) { struct reloc *reloc = insn_reloc(file, orig_insn); if (reloc) { @@ -1590,7 +1701,7 @@ static int add_special_section_alts(struct objtool_file *file) free(special_alt); } - if (stats) { + if (opts.stats) { printf("jl\\\tNOP\tJMP\n"); printf("short:\t%ld\t%ld\n", file->jl_nop_short, file->jl_short); printf("long:\t%ld\t%ld\n", file->jl_nop_long, file->jl_long); @@ -1836,6 +1947,16 @@ static int read_unwind_hints(struct objtool_file *file) insn->hint = true; + if (opts.ibt && hint->type == UNWIND_HINT_TYPE_REGS_PARTIAL) { + struct symbol *sym = find_symbol_by_offset(insn->sec, insn->offset); + + if (sym && sym->bind == STB_GLOBAL && + insn->type != INSN_ENDBR && !insn->noendbr) { + WARN_FUNC("UNWIND_HINT_IRET_REGS without ENDBR", + insn->sec, insn->offset); + } + } + if (hint->type == UNWIND_HINT_TYPE_FUNC) { insn->cfi = &func_cfi; continue; @@ -1860,6 +1981,32 @@ static int read_unwind_hints(struct objtool_file *file) return 0; } +static int read_noendbr_hints(struct objtool_file *file) +{ + struct section *sec; + struct instruction *insn; + struct reloc *reloc; + + sec = find_section_by_name(file->elf, ".rela.discard.noendbr"); + if (!sec) + return 0; + + list_for_each_entry(reloc, &sec->reloc_list, list) { + insn = find_insn(file, reloc->sym->sec, reloc->sym->offset + reloc->addend); + if (!insn) { + WARN("bad .discard.noendbr entry"); + return -1; + } + + if (insn->type == INSN_ENDBR) + WARN_FUNC("ANNOTATE_NOENDBR on ENDBR", insn->sec, insn->offset); + + insn->noendbr = 1; + } + + return 0; +} + static int read_retpoline_hints(struct objtool_file *file) { struct section *sec; @@ -2086,10 +2233,6 @@ static int decode_sections(struct objtool_file *file) if (ret) return ret; - ret = add_dead_ends(file); - if (ret) - return ret; - add_ignores(file); add_uaccess_safe(file); @@ -2098,6 +2241,13 @@ static int decode_sections(struct objtool_file *file) return ret; /* + * Must be before read_unwind_hints() since that needs insn->noendbr. + */ + ret = read_noendbr_hints(file); + if (ret) + return ret; + + /* * Must be before add_{jump_call}_destination. */ ret = classify_symbols(file); @@ -2105,14 +2255,14 @@ static int decode_sections(struct objtool_file *file) return ret; /* - * Must be before add_special_section_alts() as that depends on - * jump_dest being set. + * Must be before add_jump_destinations(), which depends on 'func' + * being set for alternatives, to enable proper sibling call detection. */ - ret = add_jump_destinations(file); + ret = add_special_section_alts(file); if (ret) return ret; - ret = add_special_section_alts(file); + ret = add_jump_destinations(file); if (ret) return ret; @@ -2128,6 +2278,14 @@ static int decode_sections(struct objtool_file *file) if (ret) return ret; + /* + * Must be after add_call_destinations() such that it can override + * dead_end_function() marks. + */ + ret = add_dead_ends(file); + if (ret) + return ret; + ret = add_jump_table_alts(file); if (ret) return ret; @@ -2650,7 +2808,7 @@ static int update_cfi_state(struct instruction *insn, } /* detect when asm code uses rbp as a scratch register */ - if (!no_fp && insn->func && op->src.reg == CFI_BP && + if (opts.stackval && insn->func && op->src.reg == CFI_BP && cfa->base != CFI_BP) cfi->bp_scratch = true; break; @@ -3046,7 +3204,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, while (1) { next_insn = next_insn_to_validate(file, insn); - if (file->c_file && func && insn->func && func != insn->func->pfunc) { + if (func && insn->func && func != insn->func->pfunc) { WARN("%s() falls through to next function %s()", func->name, insn->func->name); return 1; @@ -3099,7 +3257,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, ret = validate_branch(file, func, alt->insn, state); if (ret) { - if (backtrace) + if (opts.backtrace) BT_FUNC("(alt)", insn); return ret; } @@ -3115,12 +3273,6 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, switch (insn->type) { case INSN_RETURN: - if (next_insn && next_insn->type == INSN_TRAP) { - next_insn->ignore = true; - } else if (sls && !insn->retpoline_safe) { - WARN_FUNC("missing int3 after ret", - insn->sec, insn->offset); - } return validate_return(func, insn, &state); case INSN_CALL: @@ -3129,14 +3281,14 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, if (ret) return ret; - if (!no_fp && func && !is_fentry_call(insn) && + if (opts.stackval && func && !is_fentry_call(insn) && !has_valid_stack_frame(&state)) { WARN_FUNC("call without frame pointer save/setup", sec, insn->offset); return 1; } - if (dead_end_function(file, insn->call_dest)) + if (insn->dead_end) return 0; break; @@ -3152,7 +3304,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, ret = validate_branch(file, func, insn->jump_dest, state); if (ret) { - if (backtrace) + if (opts.backtrace) BT_FUNC("(branch)", insn); return ret; } @@ -3164,14 +3316,6 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, break; case INSN_JUMP_DYNAMIC: - if (next_insn && next_insn->type == INSN_TRAP) { - next_insn->ignore = true; - } else if (sls && !insn->retpoline_safe) { - WARN_FUNC("missing int3 after indirect jump", - insn->sec, insn->offset); - } - - /* fallthrough */ case INSN_JUMP_DYNAMIC_CONDITIONAL: if (is_sibling_call(insn)) { ret = validate_sibling_call(file, insn, &state); @@ -3263,7 +3407,7 @@ static int validate_unwind_hints(struct objtool_file *file, struct section *sec) if (!file->hints) return 0; - init_insn_state(&state, sec); + init_insn_state(file, &state, sec); if (sec) { insn = find_insn(file, sec, 0); @@ -3276,7 +3420,7 @@ static int validate_unwind_hints(struct objtool_file *file, struct section *sec) while (&insn->list != &file->insn_list && (!sec || insn->sec == sec)) { if (insn->hint && !insn->visited && !insn->ignore) { ret = validate_branch(file, insn->func, insn, state); - if (ret && backtrace) + if (ret && opts.backtrace) BT_FUNC("<=== (hint)", insn); warnings += ret; } @@ -3306,7 +3450,7 @@ static int validate_retpoline(struct objtool_file *file) * loaded late, they very much do need retpoline in their * .init.text */ - if (!strcmp(insn->sec->name, ".init.text") && !module) + if (!strcmp(insn->sec->name, ".init.text") && !opts.module) continue; WARN_FUNC("indirect %s found in RETPOLINE build", @@ -3337,7 +3481,7 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio int i; struct instruction *prev_insn; - if (insn->ignore || insn->type == INSN_NOP) + if (insn->ignore || insn->type == INSN_NOP || insn->type == INSN_TRAP) return true; /* @@ -3348,6 +3492,49 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio !strcmp(insn->sec->name, ".altinstr_aux")) return true; + /* + * Whole archive runs might encounter dead code from weak symbols. + * This is where the linker will have dropped the weak symbol in + * favour of a regular symbol, but leaves the code in place. + * + * In this case we'll find a piece of code (whole function) that is not + * covered by a !section symbol. Ignore them. + */ + if (opts.link && !insn->func) { + int size = find_symbol_hole_containing(insn->sec, insn->offset); + unsigned long end = insn->offset + size; + + if (!size) /* not a hole */ + return false; + + if (size < 0) /* hole until the end */ + return true; + + sec_for_each_insn_continue(file, insn) { + /* + * If we reach a visited instruction at or before the + * end of the hole, ignore the unreachable. + */ + if (insn->visited) + return true; + + if (insn->offset >= end) + break; + + /* + * If this hole jumps to a .cold function, mark it ignore too. + */ + if (insn->jump_dest && insn->jump_dest->func && + strstr(insn->jump_dest->func->name, ".cold")) { + struct instruction *dest = insn->jump_dest; + func_for_each_insn(file, dest->func, dest) + dest->ignore = true; + } + } + + return false; + } + if (!insn->func) return false; @@ -3420,7 +3607,7 @@ static int validate_symbol(struct objtool_file *file, struct section *sec, state->uaccess = sym->uaccess_safe; ret = validate_branch(file, insn->func, insn, *state); - if (ret && backtrace) + if (ret && opts.backtrace) BT_FUNC("<=== (sym)", insn); return ret; } @@ -3435,7 +3622,7 @@ static int validate_section(struct objtool_file *file, struct section *sec) if (func->type != STT_FUNC) continue; - init_insn_state(&state, sec); + init_insn_state(file, &state, sec); set_func_state(&state.cfi); warnings += validate_symbol(file, sec, func, &state); @@ -3444,7 +3631,7 @@ static int validate_section(struct objtool_file *file, struct section *sec) return warnings; } -static int validate_vmlinux_functions(struct objtool_file *file) +static int validate_noinstr_sections(struct objtool_file *file) { struct section *sec; int warnings = 0; @@ -3479,6 +3666,210 @@ static int validate_functions(struct objtool_file *file) return warnings; } +static void mark_endbr_used(struct instruction *insn) +{ + if (!list_empty(&insn->call_node)) + list_del_init(&insn->call_node); +} + +static int validate_ibt_insn(struct objtool_file *file, struct instruction *insn) +{ + struct instruction *dest; + struct reloc *reloc; + unsigned long off; + int warnings = 0; + + /* + * Looking for function pointer load relocations. Ignore + * direct/indirect branches: + */ + switch (insn->type) { + case INSN_CALL: + case INSN_CALL_DYNAMIC: + case INSN_JUMP_CONDITIONAL: + case INSN_JUMP_UNCONDITIONAL: + case INSN_JUMP_DYNAMIC: + case INSN_JUMP_DYNAMIC_CONDITIONAL: + case INSN_RETURN: + case INSN_NOP: + return 0; + default: + break; + } + + for (reloc = insn_reloc(file, insn); + reloc; + reloc = find_reloc_by_dest_range(file->elf, insn->sec, + reloc->offset + 1, + (insn->offset + insn->len) - (reloc->offset + 1))) { + + /* + * static_call_update() references the trampoline, which + * doesn't have (or need) ENDBR. Skip warning in that case. + */ + if (reloc->sym->static_call_tramp) + continue; + + off = reloc->sym->offset; + if (reloc->type == R_X86_64_PC32 || reloc->type == R_X86_64_PLT32) + off += arch_dest_reloc_offset(reloc->addend); + else + off += reloc->addend; + + dest = find_insn(file, reloc->sym->sec, off); + if (!dest) + continue; + + if (dest->type == INSN_ENDBR) { + mark_endbr_used(dest); + continue; + } + + if (dest->func && dest->func == insn->func) { + /* + * Anything from->to self is either _THIS_IP_ or + * IRET-to-self. + * + * There is no sane way to annotate _THIS_IP_ since the + * compiler treats the relocation as a constant and is + * happy to fold in offsets, skewing any annotation we + * do, leading to vast amounts of false-positives. + * + * There's also compiler generated _THIS_IP_ through + * KCOV and such which we have no hope of annotating. + * + * As such, blanket accept self-references without + * issue. + */ + continue; + } + + if (dest->noendbr) + continue; + + WARN_FUNC("relocation to !ENDBR: %s", + insn->sec, insn->offset, + offstr(dest->sec, dest->offset)); + + warnings++; + } + + return warnings; +} + +static int validate_ibt_data_reloc(struct objtool_file *file, + struct reloc *reloc) +{ + struct instruction *dest; + + dest = find_insn(file, reloc->sym->sec, + reloc->sym->offset + reloc->addend); + if (!dest) + return 0; + + if (dest->type == INSN_ENDBR) { + mark_endbr_used(dest); + return 0; + } + + if (dest->noendbr) + return 0; + + WARN_FUNC("data relocation to !ENDBR: %s", + reloc->sec->base, reloc->offset, + offstr(dest->sec, dest->offset)); + + return 1; +} + +/* + * Validate IBT rules and remove used ENDBR instructions from the seal list. + * Unused ENDBR instructions will be annotated for sealing (i.e., replaced with + * NOPs) later, in create_ibt_endbr_seal_sections(). + */ +static int validate_ibt(struct objtool_file *file) +{ + struct section *sec; + struct reloc *reloc; + struct instruction *insn; + int warnings = 0; + + for_each_insn(file, insn) + warnings += validate_ibt_insn(file, insn); + + for_each_sec(file, sec) { + + /* Already done by validate_ibt_insn() */ + if (sec->sh.sh_flags & SHF_EXECINSTR) + continue; + + if (!sec->reloc) + continue; + + /* + * These sections can reference text addresses, but not with + * the intent to indirect branch to them. + */ + if (!strncmp(sec->name, ".discard", 8) || + !strncmp(sec->name, ".debug", 6) || + !strcmp(sec->name, ".altinstructions") || + !strcmp(sec->name, ".ibt_endbr_seal") || + !strcmp(sec->name, ".orc_unwind_ip") || + !strcmp(sec->name, ".parainstructions") || + !strcmp(sec->name, ".retpoline_sites") || + !strcmp(sec->name, ".smp_locks") || + !strcmp(sec->name, ".static_call_sites") || + !strcmp(sec->name, "_error_injection_whitelist") || + !strcmp(sec->name, "_kprobe_blacklist") || + !strcmp(sec->name, "__bug_table") || + !strcmp(sec->name, "__ex_table") || + !strcmp(sec->name, "__jump_table") || + !strcmp(sec->name, "__mcount_loc") || + !strcmp(sec->name, "__tracepoints")) + continue; + + list_for_each_entry(reloc, &sec->reloc->reloc_list, list) + warnings += validate_ibt_data_reloc(file, reloc); + } + + return warnings; +} + +static int validate_sls(struct objtool_file *file) +{ + struct instruction *insn, *next_insn; + int warnings = 0; + + for_each_insn(file, insn) { + next_insn = next_insn_same_sec(file, insn); + + if (insn->retpoline_safe) + continue; + + switch (insn->type) { + case INSN_RETURN: + if (!next_insn || next_insn->type != INSN_TRAP) { + WARN_FUNC("missing int3 after ret", + insn->sec, insn->offset); + warnings++; + } + + break; + case INSN_JUMP_DYNAMIC: + if (!next_insn || next_insn->type != INSN_TRAP) { + WARN_FUNC("missing int3 after indirect jump", + insn->sec, insn->offset); + warnings++; + } + break; + default: + break; + } + } + + return warnings; +} + static int validate_reachable_instructions(struct objtool_file *file) { struct instruction *insn; @@ -3521,59 +3912,89 @@ int check(struct objtool_file *file) if (list_empty(&file->insn_list)) goto out; - if (vmlinux && !validate_dup) { - ret = validate_vmlinux_functions(file); + if (opts.retpoline) { + ret = validate_retpoline(file); + if (ret < 0) + return ret; + warnings += ret; + } + + if (opts.stackval || opts.orc || opts.uaccess) { + ret = validate_functions(file); if (ret < 0) goto out; + warnings += ret; + ret = validate_unwind_hints(file, NULL); + if (ret < 0) + goto out; warnings += ret; - goto out; - } - if (retpoline) { - ret = validate_retpoline(file); + if (!warnings) { + ret = validate_reachable_instructions(file); + if (ret < 0) + goto out; + warnings += ret; + } + + } else if (opts.noinstr) { + ret = validate_noinstr_sections(file); if (ret < 0) - return ret; + goto out; warnings += ret; } - ret = validate_functions(file); - if (ret < 0) - goto out; - warnings += ret; - - ret = validate_unwind_hints(file, NULL); - if (ret < 0) - goto out; - warnings += ret; + if (opts.ibt) { + ret = validate_ibt(file); + if (ret < 0) + goto out; + warnings += ret; + } - if (!warnings) { - ret = validate_reachable_instructions(file); + if (opts.sls) { + ret = validate_sls(file); if (ret < 0) goto out; warnings += ret; } - ret = create_static_call_sections(file); - if (ret < 0) - goto out; - warnings += ret; + if (opts.static_call) { + ret = create_static_call_sections(file); + if (ret < 0) + goto out; + warnings += ret; + } - if (retpoline) { + if (opts.retpoline) { ret = create_retpoline_sites_sections(file); if (ret < 0) goto out; warnings += ret; } - if (mcount) { + if (opts.mcount) { ret = create_mcount_loc_sections(file); if (ret < 0) goto out; warnings += ret; } - if (stats) { + if (opts.ibt) { + ret = create_ibt_endbr_seal_sections(file); + if (ret < 0) + goto out; + warnings += ret; + } + + if (opts.orc && !list_empty(&file->insn_list)) { + ret = orc_create(file); + if (ret < 0) + goto out; + warnings += ret; + } + + + if (opts.stats) { printf("nr_insns_visited: %ld\n", nr_insns_visited); printf("nr_cfi: %ld\n", nr_cfi); printf("nr_cfi_reused: %ld\n", nr_cfi_reused); |