objtool: Convert VALIDATE_UNRET_BEGIN to ANNOTATE

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Josh Poimboeuf <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: Peter Zijlstra

include/linux/objtool.h

@@ -130,15 +130,12 @@
  * NOTE: The macro must be used at the beginning of a global symbol, otherwise
  * it will be ignored.
  */
-.macro VALIDATE_UNRET_BEGIN
 #if defined(CONFIG_NOINSTR_VALIDATION) && \
 	(defined(CONFIG_MITIGATION_UNRET_ENTRY) || defined(CONFIG_MITIGATION_SRSO))
-.Lhere_\@:
-	.pushsection .discard.validate_unret
-	.long	.Lhere_\@ - .
-	.popsection
+#define VALIDATE_UNRET_BEGIN	ANNOTATE type=ANNOTYPE_UNRET_BEGIN
+#else
+#define VALIDATE_UNRET_BEGIN
 #endif
-.endm
 
 .macro REACHABLE
 .Lhere_\@:

include/linux/objtool_types.h

@@ -61,5 +61,6 @@ struct unwind_hint {
 #define ANNOTYPE_RETPOLINE_SAFE		2
 #define ANNOTYPE_INSTR_BEGIN		3
 #define ANNOTYPE_INSTR_END		4
+#define ANNOTYPE_UNRET_BEGIN		5
 
 #endif /* _LINUX_OBJTOOL_TYPES_H */

tools/include/linux/objtool_types.h

@@ -61,5 +61,6 @@ struct unwind_hint {
 #define ANNOTYPE_RETPOLINE_SAFE		2
 #define ANNOTYPE_INSTR_BEGIN		3
 #define ANNOTYPE_INSTR_END		4
+#define ANNOTYPE_UNRET_BEGIN		5
 
 #endif /* _LINUX_OBJTOOL_TYPES_H */

tools/objtool/check.c

@@ -2458,33 +2458,15 @@ static int __annotate_instr(int type, struct instruction *insn)
 	return 0;
 }
 
-static int read_validate_unret_hints(struct objtool_file *file)
+static int __annotate_unret(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)
+	if (type != ANNOTYPE_UNRET_BEGIN)
 		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.instr_end entry");
-			return -1;
-		}
-		insn->unret = 1;
-	}
-
+	insn->unret = 1;
 	return 0;
-}
 
+}
 
 static int read_intra_function_calls(struct objtool_file *file)
 {
@@ -2705,7 +2687,7 @@ static int decode_sections(struct objtool_file *file)
 	if (ret)
 		return ret;
 
-	ret = read_validate_unret_hints(file);
+	ret = read_annotate(file, __annotate_unret);
 	if (ret)
 		return ret;