objtool: Convert ANNOTATE_IGNORE_ALTERNATIVE to ANNOTATE

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/20241128094311.465691316@infradead.org

2 files changed, 11 insertions, 35 deletions

diff --git a/tools/include/linux/objtool_types.h b/tools/include/linux/objtool_types.h
index 16236a56364b..eab15dbe1cb7 100644
--- a/tools/include/linux/objtool_types.h
+++ b/tools/include/linux/objtool_types.h
@@ -62,5 +62,6 @@ struct unwind_hint {
 #define ANNOTYPE_INSTR_BEGIN		3
 #define ANNOTYPE_INSTR_END		4
 #define ANNOTYPE_UNRET_BEGIN		5
+#define ANNOTYPE_IGNORE_ALTS		6
 
 #endif /* _LINUX_OBJTOOL_TYPES_H */
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 2a703748cad1..ba2cb9b69399 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1310,40 +1310,6 @@ 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.
  */
@@ -2414,6 +2380,15 @@ static int read_annotate(struct objtool_file *file, int (*func)(int type, struct
 	return 0;
 }
 
+static int __annotate_ignore_alts(int type, struct instruction *insn)
+{
+	if (type != ANNOTYPE_IGNORE_ALTS)
+		return 0;
+
+	insn->ignore_alts = true;
+	return 0;
+}
+
 static int __annotate_noendbr(int type, struct instruction *insn)
 {
 	if (type != ANNOTYPE_NOENDBR)
@@ -2626,7 +2601,7 @@ static int decode_sections(struct objtool_file *file)
 	add_ignores(file);
 	add_uaccess_safe(file);
 
-	ret = add_ignore_alternatives(file);
+	ret = read_annotate(file, __annotate_ignore_alts);
 	if (ret)
 		return ret;