From bf5febebd99fddfc6226a94e937d38a8d470b24e Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Thu, 28 Nov 2024 10:38:54 +0100
Subject: [PATCH] objtool: Convert ANNOTATE_RETPOLINE_SAFE to ANNOTATE

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/20241128094311.145275669@infradead.org
---
 arch/x86/include/asm/nospec-branch.h | 13 +------
 include/linux/objtool_types.h        |  1 +
 tools/include/linux/objtool_types.h  |  1 +
 tools/objtool/check.c                | 58 ++++++++++------------------
 4 files changed, 25 insertions(+), 48 deletions(-)

diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 96b410b1d4e8..50340a125953 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -184,12 +184,7 @@
  * objtool the subsequent indirect jump/call is vouched safe for retpoline
  * builds.
  */
-.macro ANNOTATE_RETPOLINE_SAFE
-.Lhere_\@:
-	.pushsection .discard.retpoline_safe
-	.long .Lhere_\@
-	.popsection
-.endm
+#define ANNOTATE_RETPOLINE_SAFE	ANNOTATE type=ANNOTYPE_RETPOLINE_SAFE
 
 /*
  * (ab)use RETPOLINE_SAFE on RET to annotate away 'bare' RET instructions
@@ -350,11 +345,7 @@
 
 #else /* __ASSEMBLY__ */
 
-#define ANNOTATE_RETPOLINE_SAFE					\
-	"999:\n\t"						\
-	".pushsection .discard.retpoline_safe\n\t"		\
-	".long 999b\n\t"					\
-	".popsection\n\t"
+#define ANNOTATE_RETPOLINE_SAFE ASM_ANNOTATE(ANNOTYPE_RETPOLINE_SAFE)
 
 typedef u8 retpoline_thunk_t[RETPOLINE_THUNK_SIZE];
 extern retpoline_thunk_t __x86_indirect_thunk_array[];
diff --git a/include/linux/objtool_types.h b/include/linux/objtool_types.h
index 4884f8cf8429..1b348361ad1d 100644
--- a/include/linux/objtool_types.h
+++ b/include/linux/objtool_types.h
@@ -58,5 +58,6 @@ struct unwind_hint {
  * Annotate types
  */
 #define ANNOTYPE_NOENDBR		1
+#define ANNOTYPE_RETPOLINE_SAFE		2
 
 #endif /* _LINUX_OBJTOOL_TYPES_H */
diff --git a/tools/include/linux/objtool_types.h b/tools/include/linux/objtool_types.h
index 4884f8cf8429..1b348361ad1d 100644
--- a/tools/include/linux/objtool_types.h
+++ b/tools/include/linux/objtool_types.h
@@ -58,5 +58,6 @@ struct unwind_hint {
  * Annotate types
  */
 #define ANNOTYPE_NOENDBR		1
+#define ANNOTYPE_RETPOLINE_SAFE		2
 
 #endif /* _LINUX_OBJTOOL_TYPES_H */
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index a74ff26860f7..c5b52309b80d 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2373,12 +2373,12 @@ static int read_unwind_hints(struct objtool_file *file)
 	return 0;
 }
 
-static int read_annotate(struct objtool_file *file, void (*func)(int type, struct instruction *insn))
+static int read_annotate(struct objtool_file *file, int (*func)(int type, struct instruction *insn))
 {
 	struct section *sec;
 	struct instruction *insn;
 	struct reloc *reloc;
-	int type;
+	int type, ret;
 
 	sec = find_section_by_name(file->elf, ".discard.annotate_insn");
 	if (!sec)
@@ -2406,53 +2406,37 @@ static int read_annotate(struct objtool_file *file, void (*func)(int type, struc
 			return -1;
 		}
 
-		func(type, insn);
+		ret = func(type, insn);
+		if (ret < 0)
+			return ret;
 	}
 
 	return 0;
 }
 
-static void __annotate_noendbr(int type, struct instruction *insn)
+static int __annotate_noendbr(int type, struct instruction *insn)
 {
 	if (type != ANNOTYPE_NOENDBR)
-		return;
-
-	insn->noendbr = 1;
-}
-
-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;
-		}
+	insn->noendbr = 1;
+	return 0;
+}
 
-		insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
-		if (!insn) {
-			WARN("bad .discard.retpoline_safe entry");
-			return -1;
-		}
+static int __annotate_retpoline_safe(int type, struct instruction *insn)
+{
+	if (type != ANNOTYPE_RETPOLINE_SAFE)
+		return 0;
 
-		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->retpoline_safe = true;
+	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->retpoline_safe = true;
 	return 0;
 }
 
@@ -2742,7 +2726,7 @@ static int decode_sections(struct objtool_file *file)
 	if (ret)
 		return ret;
 
-	ret = read_retpoline_hints(file);
+	ret = read_annotate(file, __annotate_retpoline_safe);
 	if (ret)
 		return ret;