diff options
Diffstat (limited to 'tools/objtool/check.c')
-rw-r--r-- | tools/objtool/check.c | 674 |
1 files changed, 310 insertions, 364 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 548ec3cd7c00..ce973d9d8e6d 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -20,6 +20,7 @@ #include <linux/hashtable.h> #include <linux/kernel.h> #include <linux/static_call_types.h> +#include <linux/string.h> struct alternative { struct alternative *next; @@ -149,6 +150,15 @@ static inline struct reloc *insn_jump_table(struct instruction *insn) return NULL; } +static inline unsigned long insn_jump_table_size(struct instruction *insn) +{ + if (insn->type == INSN_JUMP_DYNAMIC || + insn->type == INSN_CALL_DYNAMIC) + return insn->_jump_table_size; + + return 0; +} + static bool is_jump_table_jump(struct instruction *insn) { struct alt_group *alt_group = insn->alt_group; @@ -177,6 +187,53 @@ static bool is_sibling_call(struct instruction *insn) } /* + * Checks if a string ends with another. + */ +static bool str_ends_with(const char *s, const char *sub) +{ + const int slen = strlen(s); + const int sublen = strlen(sub); + + if (sublen > slen) + return 0; + + return !memcmp(s + slen - sublen, sub, sublen); +} + +/* + * Checks if a function is a Rust "noreturn" one. + */ +static bool is_rust_noreturn(const struct symbol *func) +{ + /* + * If it does not start with "_R", then it is not a Rust symbol. + */ + if (strncmp(func->name, "_R", 2)) + return false; + + /* + * These are just heuristics -- we do not control the precise symbol + * name, due to the crate disambiguators (which depend on the compiler) + * as well as changes to the source code itself between versions (since + * these come from the Rust standard library). + */ + return str_ends_with(func->name, "_4core5sliceSp15copy_from_slice17len_mismatch_fail") || + str_ends_with(func->name, "_4core6option13unwrap_failed") || + str_ends_with(func->name, "_4core6result13unwrap_failed") || + str_ends_with(func->name, "_4core9panicking5panic") || + str_ends_with(func->name, "_4core9panicking9panic_fmt") || + str_ends_with(func->name, "_4core9panicking14panic_explicit") || + str_ends_with(func->name, "_4core9panicking14panic_nounwind") || + str_ends_with(func->name, "_4core9panicking18panic_bounds_check") || + str_ends_with(func->name, "_4core9panicking19assert_failed_inner") || + str_ends_with(func->name, "_4core9panicking36panic_misaligned_pointer_dereference") || + strstr(func->name, "_4core9panicking13assert_failed") || + strstr(func->name, "_4core9panicking11panic_const24panic_const_") || + (strstr(func->name, "_4core5slice5index24slice_") && + str_ends_with(func->name, "_fail")); +} + +/* * This checks to see if the given function is a "noreturn" function. * * For global functions which are outside the scope of this object file, we @@ -201,10 +258,14 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func, if (!func) return false; - if (func->bind == STB_GLOBAL || func->bind == STB_WEAK) + if (func->bind == STB_GLOBAL || func->bind == STB_WEAK) { + if (is_rust_noreturn(func)) + return true; + for (i = 0; i < ARRAY_SIZE(global_noreturns); i++) if (!strcmp(func->name, global_noreturns[i])) return true; + } if (func->bind == STB_WEAK) return false; @@ -563,106 +624,6 @@ static int init_pv_ops(struct objtool_file *file) return 0; } -static struct instruction *find_last_insn(struct objtool_file *file, - struct section *sec) -{ - struct instruction *insn = NULL; - unsigned int offset; - unsigned int end = (sec->sh.sh_size > 10) ? sec->sh.sh_size - 10 : 0; - - for (offset = sec->sh.sh_size - 1; offset >= end && !insn; offset--) - insn = find_insn(file, sec, offset); - - return insn; -} - -/* - * Mark "ud2" instructions and manually annotated dead ends. - */ -static int add_dead_ends(struct objtool_file *file) -{ - struct section *rsec; - struct reloc *reloc; - struct instruction *insn; - s64 addend; - - /* - * Check for manually annotated dead ends. - */ - rsec = find_section_by_name(file->elf, ".rela.discard.unreachable"); - if (!rsec) - goto reachable; - - for_each_reloc(rsec, reloc) { - - if (reloc->sym->type != STT_SECTION) { - WARN("unexpected relocation symbol type in %s", rsec->name); - return -1; - } - - addend = reloc_addend(reloc); - - insn = find_insn(file, reloc->sym->sec, addend); - if (insn) - insn = prev_insn_same_sec(file, insn); - else if (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%" PRIx64, - reloc->sym->sec->name, addend); - return -1; - } - } else { - WARN("can't find unreachable insn at %s+0x%" PRIx64, - reloc->sym->sec->name, addend); - return -1; - } - - insn->dead_end = true; - } - -reachable: - /* - * These manually annotated reachable checks are needed for GCC 4.4, - * where the Linux unreachable() macro isn't supported. In that case - * GCC doesn't know the "ud2" is fatal, so it generates code as if it's - * not a dead end. - */ - rsec = find_section_by_name(file->elf, ".rela.discard.reachable"); - if (!rsec) - return 0; - - for_each_reloc(rsec, reloc) { - - if (reloc->sym->type != STT_SECTION) { - WARN("unexpected relocation symbol type in %s", rsec->name); - return -1; - } - - addend = reloc_addend(reloc); - - insn = find_insn(file, reloc->sym->sec, addend); - if (insn) - insn = prev_insn_same_sec(file, insn); - else if (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%" PRIx64, - reloc->sym->sec->name, addend); - return -1; - } - } else { - WARN("can't find reachable insn at %s+0x%" PRIx64, - reloc->sym->sec->name, addend); - return -1; - } - - insn->dead_end = false; - } - - return 0; -} - static int create_static_call_sections(struct objtool_file *file) { struct static_call_site *site; @@ -1199,6 +1160,8 @@ static const char *uaccess_safe_builtin[] = { "__sanitizer_cov_trace_switch", /* KMSAN */ "kmsan_copy_to_user", + "kmsan_disable_current", + "kmsan_enable_current", "kmsan_report", "kmsan_unpoison_entry_regs", "kmsan_unpoison_memory", @@ -1255,40 +1218,6 @@ static void add_uaccess_safe(struct objtool_file *file) } /* - * FIXME: For now, just ignore any alternatives which add retpolines. This is - * a temporary hack, as it doesn't allow ORC to unwind from inside a retpoline. - * But it at least allows objtool to understand the control flow *around* the - * retpoline. - */ -static int add_ignore_alternatives(struct objtool_file *file) -{ - struct section *rsec; - struct reloc *reloc; - struct instruction *insn; - - rsec = find_section_by_name(file->elf, ".rela.discard.ignore_alts"); - if (!rsec) - return 0; - - for_each_reloc(rsec, reloc) { - if (reloc->sym->type != STT_SECTION) { - WARN("unexpected relocation symbol type in %s", rsec->name); - return -1; - } - - insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc)); - if (!insn) { - WARN("bad .discard.ignore_alts entry"); - return -1; - } - - insn->ignore_alts = true; - } - - return 0; -} - -/* * Symbols that replace INSN_CALL_DYNAMIC, every (tail) call to such a symbol * will be added to the .retpoline_sites section. */ @@ -2018,6 +1947,7 @@ out: static int add_jump_table(struct objtool_file *file, struct instruction *insn, struct reloc *next_table) { + unsigned long table_size = insn_jump_table_size(insn); struct symbol *pfunc = insn_func(insn)->pfunc; struct reloc *table = insn_jump_table(insn); struct instruction *dest_insn; @@ -2032,6 +1962,8 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn, for_each_reloc_from(table->sec, reloc) { /* Check for the end of the table: */ + if (table_size && reloc_offset(reloc) - reloc_offset(table) >= table_size) + break; if (reloc != table && reloc == next_table) break; @@ -2044,6 +1976,14 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn, reloc_addend(reloc) == pfunc->offset) break; + /* + * Clang sometimes leaves dangling unused jump table entries + * which point to the end of the function. Ignore them. + */ + if (reloc->sym->sec == pfunc->sec && + reloc_addend(reloc) == pfunc->offset + pfunc->len) + goto next; + dest_insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc)); if (!dest_insn) break; @@ -2061,6 +2001,7 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn, alt->insn = dest_insn; alt->next = insn->alts; insn->alts = alt; +next: prev_offset = reloc_offset(reloc); } @@ -2076,12 +2017,12 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn, * find_jump_table() - Given a dynamic jump, find the switch jump table * associated with it. */ -static struct reloc *find_jump_table(struct objtool_file *file, - struct symbol *func, - struct instruction *insn) +static void find_jump_table(struct objtool_file *file, struct symbol *func, + struct instruction *insn) { struct reloc *table_reloc; struct instruction *dest_insn, *orig_insn = insn; + unsigned long table_size; /* * Backward search using the @first_jump_src links, these help avoid @@ -2102,17 +2043,17 @@ static struct reloc *find_jump_table(struct objtool_file *file, insn->jump_dest->offset > orig_insn->offset)) break; - table_reloc = arch_find_switch_table(file, insn); + table_reloc = arch_find_switch_table(file, insn, &table_size); if (!table_reloc) continue; dest_insn = find_insn(file, table_reloc->sym->sec, reloc_addend(table_reloc)); if (!dest_insn || !insn_func(dest_insn) || insn_func(dest_insn)->pfunc != func) continue; - return table_reloc; + orig_insn->_jump_table = table_reloc; + orig_insn->_jump_table_size = table_size; + break; } - - return NULL; } /* @@ -2123,7 +2064,6 @@ static void mark_func_jump_tables(struct objtool_file *file, struct symbol *func) { struct instruction *insn, *last = NULL; - struct reloc *reloc; func_for_each_insn(file, func, insn) { if (!last) @@ -2146,9 +2086,7 @@ static void mark_func_jump_tables(struct objtool_file *file, if (insn->type != INSN_JUMP_DYNAMIC) continue; - reloc = find_jump_table(file, func, insn); - if (reloc) - insn->_jump_table = reloc; + find_jump_table(file, func, insn); } } @@ -2224,6 +2162,7 @@ static int read_unwind_hints(struct objtool_file *file) struct unwind_hint *hint; struct instruction *insn; struct reloc *reloc; + unsigned long offset; int i; sec = find_section_by_name(file->elf, ".discard.unwind_hints"); @@ -2251,7 +2190,16 @@ static int read_unwind_hints(struct objtool_file *file) return -1; } - insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc)); + if (reloc->sym->type == STT_SECTION) { + offset = reloc_addend(reloc); + } else if (reloc->sym->local_label) { + offset = reloc->sym->offset; + } else { + WARN("unexpected relocation symbol type in %s", sec->rsec->name); + return -1; + } + + insn = find_insn(file, reloc->sym->sec, offset); if (!insn) { WARN("can't find insn for unwind_hints[%d]", i); return -1; @@ -2308,185 +2256,147 @@ static int read_unwind_hints(struct objtool_file *file) return 0; } -static int read_noendbr_hints(struct objtool_file *file) +static int read_annotate(struct objtool_file *file, + int (*func)(struct objtool_file *file, int type, struct instruction *insn)) { + struct section *sec; struct instruction *insn; - struct section *rsec; struct reloc *reloc; + uint64_t offset; + int type, ret; - rsec = find_section_by_name(file->elf, ".rela.discard.noendbr"); - if (!rsec) + sec = find_section_by_name(file->elf, ".discard.annotate_insn"); + if (!sec) return 0; - for_each_reloc(rsec, reloc) { - insn = find_insn(file, reloc->sym->sec, - reloc->sym->offset + reloc_addend(reloc)); - if (!insn) { - WARN("bad .discard.noendbr entry"); - return -1; - } + if (!sec->rsec) + return 0; - insn->noendbr = 1; + if (sec->sh.sh_entsize != 8) { + static bool warned = false; + if (!warned && opts.verbose) { + WARN("%s: dodgy linker, sh_entsize != 8", sec->name); + warned = true; + } + sec->sh.sh_entsize = 8; } - return 0; -} - -static int read_retpoline_hints(struct objtool_file *file) -{ - struct section *rsec; - struct instruction *insn; - struct reloc *reloc; - - rsec = find_section_by_name(file->elf, ".rela.discard.retpoline_safe"); - if (!rsec) - return 0; + for_each_reloc(sec->rsec, reloc) { + type = *(u32 *)(sec->data->d_buf + (reloc_idx(reloc) * sec->sh.sh_entsize) + 4); - for_each_reloc(rsec, reloc) { - if (reloc->sym->type != STT_SECTION) { - WARN("unexpected relocation symbol type in %s", rsec->name); - return -1; - } + offset = reloc->sym->offset + reloc_addend(reloc); + insn = find_insn(file, reloc->sym->sec, offset); - insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc)); if (!insn) { - WARN("bad .discard.retpoline_safe entry"); - return -1; - } - - if (insn->type != INSN_JUMP_DYNAMIC && - insn->type != INSN_CALL_DYNAMIC && - insn->type != INSN_RETURN && - insn->type != INSN_NOP) { - WARN_INSN(insn, "retpoline_safe hint not an indirect jump/call/ret/nop"); + WARN("bad .discard.annotate_insn entry: %d of type %d", reloc_idx(reloc), type); return -1; } - insn->retpoline_safe = true; + ret = func(file, type, insn); + if (ret < 0) + return ret; } return 0; } -static int read_instr_hints(struct objtool_file *file) +static int __annotate_early(struct objtool_file *file, int type, struct instruction *insn) { - struct section *rsec; - struct instruction *insn; - struct reloc *reloc; + switch (type) { + case ANNOTYPE_IGNORE_ALTS: + insn->ignore_alts = true; + break; - rsec = find_section_by_name(file->elf, ".rela.discard.instr_end"); - if (!rsec) - return 0; + /* + * Must be before read_unwind_hints() since that needs insn->noendbr. + */ + case ANNOTYPE_NOENDBR: + insn->noendbr = 1; + break; - for_each_reloc(rsec, reloc) { - if (reloc->sym->type != STT_SECTION) { - WARN("unexpected relocation symbol type in %s", rsec->name); - return -1; - } + default: + break; + } - insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc)); - if (!insn) { - WARN("bad .discard.instr_end entry"); - return -1; - } + return 0; +} - insn->instr--; - } +static int __annotate_ifc(struct objtool_file *file, int type, struct instruction *insn) +{ + unsigned long dest_off; - rsec = find_section_by_name(file->elf, ".rela.discard.instr_begin"); - if (!rsec) + if (type != ANNOTYPE_INTRA_FUNCTION_CALL) return 0; - for_each_reloc(rsec, reloc) { - if (reloc->sym->type != STT_SECTION) { - WARN("unexpected relocation symbol type in %s", rsec->name); - return -1; - } + if (insn->type != INSN_CALL) { + WARN_INSN(insn, "intra_function_call not a direct call"); + return -1; + } - insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc)); - if (!insn) { - WARN("bad .discard.instr_begin entry"); - return -1; - } + /* + * Treat intra-function CALLs as JMPs, but with a stack_op. + * See add_call_destinations(), which strips stack_ops from + * normal CALLs. + */ + insn->type = INSN_JUMP_UNCONDITIONAL; - insn->instr++; + dest_off = arch_jump_destination(insn); + insn->jump_dest = find_insn(file, insn->sec, dest_off); + if (!insn->jump_dest) { + WARN_INSN(insn, "can't find call dest at %s+0x%lx", + insn->sec->name, dest_off); + return -1; } return 0; } -static int read_validate_unret_hints(struct objtool_file *file) +static int __annotate_late(struct objtool_file *file, int type, struct instruction *insn) { - struct section *rsec; - struct instruction *insn; - struct reloc *reloc; - - rsec = find_section_by_name(file->elf, ".rela.discard.validate_unret"); - if (!rsec) - return 0; - - for_each_reloc(rsec, reloc) { - if (reloc->sym->type != STT_SECTION) { - WARN("unexpected relocation symbol type in %s", rsec->name); - return -1; - } + switch (type) { + case ANNOTYPE_NOENDBR: + /* early */ + break; - insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc)); - if (!insn) { - WARN("bad .discard.instr_end entry"); + case ANNOTYPE_RETPOLINE_SAFE: + if (insn->type != INSN_JUMP_DYNAMIC && + insn->type != INSN_CALL_DYNAMIC && + insn->type != INSN_RETURN && + insn->type != INSN_NOP) { + WARN_INSN(insn, "retpoline_safe hint not an indirect jump/call/ret/nop"); return -1; } - insn->unret = 1; - } - - return 0; -} - -static int read_intra_function_calls(struct objtool_file *file) -{ - struct instruction *insn; - struct section *rsec; - struct reloc *reloc; + insn->retpoline_safe = true; + break; - rsec = find_section_by_name(file->elf, ".rela.discard.intra_function_calls"); - if (!rsec) - return 0; + case ANNOTYPE_INSTR_BEGIN: + insn->instr++; + break; - for_each_reloc(rsec, reloc) { - unsigned long dest_off; + case ANNOTYPE_INSTR_END: + insn->instr--; + break; - if (reloc->sym->type != STT_SECTION) { - WARN("unexpected relocation symbol type in %s", - rsec->name); - return -1; - } + case ANNOTYPE_UNRET_BEGIN: + insn->unret = 1; + break; - insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc)); - if (!insn) { - WARN("bad .discard.intra_function_call entry"); - return -1; - } + case ANNOTYPE_IGNORE_ALTS: + /* early */ + break; - if (insn->type != INSN_CALL) { - WARN_INSN(insn, "intra_function_call not a direct call"); - return -1; - } + case ANNOTYPE_INTRA_FUNCTION_CALL: + /* ifc */ + break; - /* - * Treat intra-function CALLs as JMPs, but with a stack_op. - * See add_call_destinations(), which strips stack_ops from - * normal CALLs. - */ - insn->type = INSN_JUMP_UNCONDITIONAL; + case ANNOTYPE_REACHABLE: + insn->dead_end = false; + break; - dest_off = arch_jump_destination(insn); - insn->jump_dest = find_insn(file, insn->sec, dest_off); - if (!insn->jump_dest) { - WARN_INSN(insn, "can't find call dest at %s+0x%lx", - insn->sec->name, dest_off); - return -1; - } + default: + WARN_INSN(insn, "Unknown annotation type: %d", type); + break; } return 0; @@ -2522,6 +2432,9 @@ static int classify_symbols(struct objtool_file *file) struct symbol *func; for_each_sym(file, func) { + if (func->type == STT_NOTYPE && strstarts(func->name, ".L")) + func->local_label = true; + if (func->bind != STB_GLOBAL) continue; @@ -2559,13 +2472,14 @@ static void mark_rodata(struct objtool_file *file) * * - .rodata: can contain GCC switch tables * - .rodata.<func>: same, if -fdata-sections is being used - * - .rodata..c_jump_table: contains C annotated jump tables + * - .data.rel.ro.c_jump_table: contains C annotated jump tables * * .rodata.str1.* sections are ignored; they don't contain jump tables. */ for_each_sec(file, sec) { - if (!strncmp(sec->name, ".rodata", 7) && - !strstr(sec->name, ".str1.")) { + if ((!strncmp(sec->name, ".rodata", 7) && + !strstr(sec->name, ".str1.")) || + !strncmp(sec->name, ".data.rel.ro", 12)) { sec->rodata = true; found = true; } @@ -2598,14 +2512,7 @@ static int decode_sections(struct objtool_file *file) add_ignores(file); add_uaccess_safe(file); - ret = add_ignore_alternatives(file); - if (ret) - return ret; - - /* - * Must be before read_unwind_hints() since that needs insn->noendbr. - */ - ret = read_noendbr_hints(file); + ret = read_annotate(file, __annotate_early); if (ret) return ret; @@ -2627,7 +2534,7 @@ static int decode_sections(struct objtool_file *file) * Must be before add_call_destination(); it changes INSN_CALL to * INSN_JUMP. */ - ret = read_intra_function_calls(file); + ret = read_annotate(file, __annotate_ifc); if (ret) return ret; @@ -2635,14 +2542,6 @@ 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; @@ -2651,15 +2550,11 @@ static int decode_sections(struct objtool_file *file) if (ret) return ret; - ret = read_retpoline_hints(file); - if (ret) - return ret; - - ret = read_instr_hints(file); - if (ret) - return ret; - - ret = read_validate_unret_hints(file); + /* + * Must be after add_call_destinations() such that it can override + * dead_end_function() marks. + */ + ret = read_annotate(file, __annotate_late); if (ret) return ret; @@ -2975,10 +2870,27 @@ static int update_cfi_state(struct instruction *insn, break; } - if (op->dest.reg == CFI_SP && op->src.reg == CFI_BP) { + if (op->dest.reg == CFI_BP && op->src.reg == CFI_SP && + insn->sym->frame_pointer) { + /* addi.d fp,sp,imm on LoongArch */ + if (cfa->base == CFI_SP && cfa->offset == op->src.offset) { + cfa->base = CFI_BP; + cfa->offset = 0; + } + break; + } - /* lea disp(%rbp), %rsp */ - cfi->stack_size = -(op->src.offset + regs[CFI_BP].offset); + if (op->dest.reg == CFI_SP && op->src.reg == CFI_BP) { + /* addi.d sp,fp,imm on LoongArch */ + if (cfa->base == CFI_BP && cfa->offset == 0) { + if (insn->sym->frame_pointer) { + cfa->base = CFI_SP; + cfa->offset = -op->src.offset; + } + } else { + /* lea disp(%rbp), %rsp */ + cfi->stack_size = -(op->src.offset + regs[CFI_BP].offset); + } break; } @@ -3620,6 +3532,18 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, } if (!save_insn->visited) { + /* + * If the restore hint insn is at the + * beginning of a basic block and was + * branched to from elsewhere, and the + * save insn hasn't been visited yet, + * defer following this branch for now. + * It will be seen later via the + * straight-line path. + */ + if (!prev_insn) + return 0; + WARN_INSN(insn, "objtool isn't smart enough to handle this CFI save/restore combo"); return 1; } @@ -3723,9 +3647,12 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, break; case INSN_CONTEXT_SWITCH: - if (func && (!next_insn || !next_insn->hint)) { - WARN_INSN(insn, "unsupported instruction in callable function"); - return 1; + if (func) { + if (!next_insn || !next_insn->hint) { + WARN_INSN(insn, "unsupported instruction in callable function"); + return 1; + } + break; } return 0; @@ -3980,11 +3907,11 @@ static int validate_retpoline(struct objtool_file *file) if (insn->type == INSN_RETURN) { if (opts.rethunk) { - WARN_INSN(insn, "'naked' return found in RETHUNK build"); + WARN_INSN(insn, "'naked' return found in MITIGATION_RETHUNK build"); } else continue; } else { - WARN_INSN(insn, "indirect %s found in RETPOLINE build", + WARN_INSN(insn, "indirect %s found in MITIGATION_RETPOLINE build", insn->type == INSN_JUMP_DYNAMIC ? "jump" : "call"); } @@ -4295,6 +4222,51 @@ static bool noendbr_range(struct objtool_file *file, struct instruction *insn) return insn->offset == sym->offset + sym->len; } +static int __validate_ibt_insn(struct objtool_file *file, struct instruction *insn, + struct instruction *dest) +{ + if (dest->type == INSN_ENDBR) { + mark_endbr_used(dest); + return 0; + } + + if (insn_func(dest) && insn_func(insn) && + insn_func(dest)->pfunc == insn_func(insn)->pfunc) { + /* + * 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. + */ + return 0; + } + + /* + * Accept anything ANNOTATE_NOENDBR. + */ + if (dest->noendbr) + return 0; + + /* + * Accept if this is the instruction after a symbol + * that is (no)endbr -- typical code-range usage. + */ + if (noendbr_range(file, dest)) + return 0; + + WARN_INSN(insn, "relocation to !ENDBR: %s", offstr(dest->sec, dest->offset)); + return 1; +} + static int validate_ibt_insn(struct objtool_file *file, struct instruction *insn) { struct instruction *dest; @@ -4307,6 +4279,7 @@ static int validate_ibt_insn(struct objtool_file *file, struct instruction *insn * direct/indirect branches: */ switch (insn->type) { + case INSN_CALL: case INSN_CALL_DYNAMIC: case INSN_JUMP_CONDITIONAL: @@ -4316,6 +4289,23 @@ static int validate_ibt_insn(struct objtool_file *file, struct instruction *insn case INSN_RETURN: case INSN_NOP: return 0; + + case INSN_LEA_RIP: + if (!insn_reloc(file, insn)) { + /* local function pointer reference without reloc */ + + off = arch_jump_destination(insn); + + dest = find_insn(file, insn->sec, off); + if (!dest) { + WARN_INSN(insn, "corrupt function pointer reference"); + return 1; + } + + return __validate_ibt_insn(file, insn, dest); + } + break; + default: break; } @@ -4326,13 +4316,6 @@ static int validate_ibt_insn(struct objtool_file *file, struct instruction *insn reloc_offset(reloc) + 1, (insn->offset + insn->len) - (reloc_offset(reloc) + 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(reloc) == R_X86_64_PC32 || reloc_type(reloc) == R_X86_64_PLT32) @@ -4344,47 +4327,7 @@ static int validate_ibt_insn(struct objtool_file *file, struct instruction *insn if (!dest) continue; - if (dest->type == INSN_ENDBR) { - mark_endbr_used(dest); - continue; - } - - if (insn_func(dest) && insn_func(insn) && - insn_func(dest)->pfunc == insn_func(insn)->pfunc) { - /* - * 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; - } - - /* - * Accept anything ANNOTATE_NOENDBR. - */ - if (dest->noendbr) - continue; - - /* - * Accept if this is the instruction after a symbol - * that is (no)endbr -- typical code-range usage. - */ - if (noendbr_range(file, dest)) - continue; - - WARN_INSN(insn, "relocation to !ENDBR: %s", offstr(dest->sec, dest->offset)); - - warnings++; + warnings += __validate_ibt_insn(file, insn, dest); } return warnings; @@ -4460,6 +4403,9 @@ static int validate_ibt(struct objtool_file *file) !strcmp(sec->name, "__jump_table") || !strcmp(sec->name, "__mcount_loc") || !strcmp(sec->name, ".kcfi_traps") || + !strcmp(sec->name, ".llvm.call-graph-profile") || + !strcmp(sec->name, ".llvm_bb_addr_map") || + !strcmp(sec->name, "__tracepoints") || strstr(sec->name, "__patchable_function_entries")) continue; |