1 files changed, 174 insertions, 362 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 76060da755b5..ca3435acc326 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -150,6 +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;
@@ -218,6 +227,7 @@ static bool is_rust_noreturn(const struct symbol *func)
 	       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"));
@@ -614,108 +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;
-	uint64_t offset;
-
-	/*
-	 * 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) {
-			offset = reloc_addend(reloc);
-		} else if (reloc->sym->local_label) {
-			offset = reloc->sym->offset;
-		} else {
-			WARN("unexpected relocation symbol type in %s", rsec->name);
-			return -1;
-		}
-
-		insn = find_insn(file, reloc->sym->sec, offset);
-		if (insn)
-			insn = prev_insn_same_sec(file, insn);
-		else if (offset == 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, offset);
-				return -1;
-			}
-		} else {
-			WARN("can't find unreachable insn at %s+0x%" PRIx64,
-			     reloc->sym->sec->name, offset);
-			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) {
-			offset = reloc_addend(reloc);
-		} else if (reloc->sym->local_label) {
-			offset = reloc->sym->offset;
-		} else {
-			WARN("unexpected relocation symbol type in %s", rsec->name);
-			return -1;
-		}
-
-		insn = find_insn(file, reloc->sym->sec, offset);
-		if (insn)
-			insn = prev_insn_same_sec(file, insn);
-		else if (offset == 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, offset);
-				return -1;
-			}
-		} else {
-			WARN("can't find reachable insn at %s+0x%" PRIx64,
-			     reloc->sym->sec->name, offset);
-			return -1;
-		}
-
-		insn->dead_end = false;
-	}
-
-	return 0;
-}
-
 static int create_static_call_sections(struct objtool_file *file)
 {
 	struct static_call_site *site;
@@ -1310,40 +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.
  */
@@ -1410,15 +1284,6 @@ static void annotate_call_site(struct objtool_file *file,
 	if (!sym)
 		sym = reloc->sym;
 
-	/*
-	 * Alternative replacement code is just template code which is
-	 * sometimes copied to the original instruction. For now, don't
-	 * annotate it. (In the future we might consider annotating the
-	 * original instruction if/when it ever makes sense to do so.)
-	 */
-	if (!strcmp(insn->sec->name, ".altinstr_replacement"))
-		return;
-
 	if (sym->static_call_tramp) {
 		list_add_tail(&insn->call_node, &file->static_call_list);
 		return;
@@ -1476,7 +1341,8 @@ static void annotate_call_site(struct objtool_file *file,
 		return;
 	}
 
-	if (insn->type == INSN_CALL && !insn->sec->init)
+	if (insn->type == INSN_CALL && !insn->sec->init &&
+	    !insn->_call_dest->embedded_insn)
 		list_add_tail(&insn->call_node, &file->call_list);
 
 	if (!sibling && dead_end_function(file, sym))
@@ -2070,15 +1936,22 @@ out:
 	return ret;
 }
 
+__weak unsigned long arch_jump_table_sym_offset(struct reloc *reloc, struct reloc *table)
+{
+	return reloc->sym->offset + reloc_addend(reloc);
+}
+
 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;
 	unsigned int prev_offset = 0;
 	struct reloc *reloc = table;
 	struct alternative *alt;
+	unsigned long sym_offset;
 
 	/*
 	 * Each @reloc is a switch table relocation which points to the target
@@ -2087,19 +1960,30 @@ 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;
 
 		/* Make sure the table entries are consecutive: */
-		if (prev_offset && reloc_offset(reloc) != prev_offset + 8)
+		if (prev_offset && reloc_offset(reloc) != prev_offset + arch_reloc_size(reloc))
 			break;
 
+		sym_offset = arch_jump_table_sym_offset(reloc, table);
+
 		/* Detect function pointers from contiguous objects: */
-		if (reloc->sym->sec == pfunc->sec &&
-		    reloc_addend(reloc) == pfunc->offset)
+		if (reloc->sym->sec == pfunc->sec && sym_offset == pfunc->offset)
 			break;
 
-		dest_insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+		/*
+		 * Clang sometimes leaves dangling unused jump table entries
+		 * which point to the end of the function.  Ignore them.
+		 */
+		if (reloc->sym->sec == pfunc->sec &&
+		    sym_offset == pfunc->offset + pfunc->len)
+			goto next;
+
+		dest_insn = find_insn(file, reloc->sym->sec, sym_offset);
 		if (!dest_insn)
 			break;
 
@@ -2116,6 +2000,7 @@ 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);
 	}
 
@@ -2131,12 +2016,13 @@ 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;
+	unsigned long sym_offset;
 
 	/*
 	 * Backward search using the @first_jump_src links, these help avoid
@@ -2157,17 +2043,20 @@ 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));
+
+		sym_offset = table_reloc->sym->offset + reloc_addend(table_reloc);
+
+		dest_insn = find_insn(file, table_reloc->sym->sec, sym_offset);
 		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;
 }
 
 /*
@@ -2178,7 +2067,6 @@ 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)
@@ -2201,9 +2089,7 @@ 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);
 	}
 }
 
@@ -2373,185 +2259,147 @@ 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;
-}
+	for_each_reloc(sec->rsec, reloc) {
+		type = *(u32 *)(sec->data->d_buf + (reloc_idx(reloc) * sec->sh.sh_entsize) + 4);
 
-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(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;
@@ -2627,13 +2475,14 @@ 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;
 		}
@@ -2666,14 +2515,7 @@ 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;
 
@@ -2695,7 +2537,7 @@ 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;
 
@@ -2703,14 +2545,6 @@ 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;
@@ -2719,15 +2553,11 @@ 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;
 
@@ -4622,35 +4452,6 @@ static int validate_sls(struct objtool_file *file)
 	return warnings;
 }
 
-static bool ignore_noreturn_call(struct instruction *insn)
-{
-	struct symbol *call_dest = insn_call_dest(insn);
-
-	/*
-	 * FIXME: hack, we need a real noreturn solution
-	 *
-	 * Problem is, exc_double_fault() may or may not return, depending on
-	 * whether CONFIG_X86_ESPFIX64 is set.  But objtool has no visibility
-	 * to the kernel config.
-	 *
-	 * Other potential ways to fix it:
-	 *
-	 *   - have compiler communicate __noreturn functions somehow
-	 *   - remove CONFIG_X86_ESPFIX64
-	 *   - read the .config file
-	 *   - add a cmdline option
-	 *   - create a generic objtool annotation format (vs a bunch of custom
-	 *     formats) and annotate it
-	 */
-	if (!strcmp(call_dest->name, "exc_double_fault")) {
-		/* prevent further unreachable warnings for the caller */
-		insn->sym->warned = 1;
-		return true;
-	}
-
-	return false;
-}
-
 static int validate_reachable_instructions(struct objtool_file *file)
 {
 	struct instruction *insn, *prev_insn;
@@ -4667,8 +4468,8 @@ static int validate_reachable_instructions(struct objtool_file *file)
 		prev_insn = prev_insn_same_sec(file, insn);
 		if (prev_insn && prev_insn->dead_end) {
 			call_dest = insn_call_dest(prev_insn);
-			if (call_dest && !ignore_noreturn_call(prev_insn)) {
-				WARN_INSN(insn, "%s() is missing a __noreturn annotation",
+			if (call_dest) {
+				WARN_INSN(insn, "%s() missing __noreturn in .c/.h or NORETURN() in noreturns.h",
 					  call_dest->name);
 				warnings++;
 				continue;
@@ -4738,7 +4539,7 @@ static int disas_warned_funcs(struct objtool_file *file)
 	char *funcs = NULL, *tmp;
 
 	for_each_sym(file, sym) {
-		if (sym->warned) {
+		if (sym->warnings) {
 			if (!funcs) {
 				funcs = malloc(strlen(sym->name) + 1);
 				strcpy(funcs, sym->name);
@@ -4796,8 +4597,10 @@ int check(struct objtool_file *file)
 	init_cfi_state(&force_undefined_cfi);
 	force_undefined_cfi.force_undefined = true;
 
-	if (!cfi_hash_alloc(1UL << (file->elf->symbol_bits - 3)))
+	if (!cfi_hash_alloc(1UL << (file->elf->symbol_bits - 3))) {
+		ret = -1;
 		goto out;
+	}
 
 	cfi_hash_add(&init_cfi);
 	cfi_hash_add(&func_cfi);
@@ -4814,7 +4617,7 @@ int check(struct objtool_file *file)
 	if (opts.retpoline) {
 		ret = validate_retpoline(file);
 		if (ret < 0)
-			return ret;
+			goto out;
 		warnings += ret;
 	}
 
@@ -4850,7 +4653,7 @@ int check(struct objtool_file *file)
 		 */
 		ret = validate_unrets(file);
 		if (ret < 0)
-			return ret;
+			goto out;
 		warnings += ret;
 	}
 
@@ -4913,7 +4716,7 @@ int check(struct objtool_file *file)
 	if (opts.prefix) {
 		ret = add_prefix_symbols(file);
 		if (ret < 0)
-			return ret;
+			goto out;
 		warnings += ret;
 	}
 
@@ -4945,9 +4748,18 @@ int check(struct objtool_file *file)
 
 out:
 	/*
-	 *  For now, don't fail the kernel build on fatal warnings.  These
-	 *  errors are still fairly common due to the growing matrix of
-	 *  supported toolchains and their recent pace of change.
+	 * CONFIG_OBJTOOL_WERROR upgrades all warnings (and errors) to actual
+	 * errors.
+	 *
+	 * Note that even "fatal" type errors don't actually return an error
+	 * without CONFIG_OBJTOOL_WERROR.  That probably needs improved at some
+	 * point.
 	 */
+	if (opts.werror && (ret || warnings)) {
+		if (warnings)
+			WARN("%d warning(s) upgraded to errors", warnings);
+		return 1;
+	}
+
 	return 0;
 }