linux-kernel - [PATCH v4 02/13] objtool: Factor out CFI hints

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Message-Id: <20200325174605.455086309@infradead.org>
Date:   Wed, 25 Mar 2020 18:45:27 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     tglx@...utronix.de, jpoimboe@...hat.com
Cc:     linux-kernel@...r.kernel.org, x86@...nel.org, peterz@...radead.org,
        mhiramat@...nel.org, mbenes@...e.cz
Subject: [PATCH v4 02/13] objtool: Factor out CFI hints

Move the application of CFI hints into it's own function.
No functional changes intended.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Acked-by: Josh Poimboeuf <jpoimboe@...hat.com>
---
 tools/objtool/check.c |   67 ++++++++++++++++++++++++++++----------------------
 1 file changed, 38 insertions(+), 29 deletions(-)

--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2033,6 +2033,41 @@ static int validate_return(struct symbol
 	return 0;
 }
 
+static int apply_insn_hint(struct objtool_file *file, struct section *sec,
+			   struct symbol *func, struct instruction *insn,
+			   struct insn_state *state)
+{
+	if (insn->restore) {
+		struct instruction *save_insn, *i;
+
+		i = insn;
+		save_insn = NULL;
+		sym_for_each_insn_continue_reverse(file, func, i) {
+			if (i->save) {
+				save_insn = i;
+				break;
+			}
+		}
+
+		if (!save_insn) {
+			WARN_FUNC("no corresponding CFI save for CFI restore",
+				  sec, insn->offset);
+			return 1;
+		}
+
+		if (!save_insn->visited) {
+			WARN_FUNC("objtool isn't smart enough to handle this CFI save/restore combo",
+				  sec, insn->offset);
+			return 1;
+		}
+
+		insn->state = save_insn->state;
+	}
+
+	state = insn->state;
+	return 0;
+}
+
 /*
  * Follow the branch starting at the given instruction, and recursively follow
  * any other branches (jumps).  Meanwhile, track the frame pointer state at
@@ -2081,35 +2116,9 @@ static int validate_branch(struct objtoo
 		}
 
 		if (insn->hint) {
-			if (insn->restore) {
-				struct instruction *save_insn, *i;
-
-				i = insn;
-				save_insn = NULL;
-				sym_for_each_insn_continue_reverse(file, func, i) {
-					if (i->save) {
-						save_insn = i;
-						break;
-					}
-				}
-
-				if (!save_insn) {
-					WARN_FUNC("no corresponding CFI save for CFI restore",
-						  sec, insn->offset);
-					return 1;
-				}
-
-				if (!save_insn->visited) {
-					WARN_FUNC("objtool isn't smart enough to handle this CFI save/restore combo",
-						  sec, insn->offset);
-					return 1;
-				}
-
-				insn->state = save_insn->state;
-			}
-
-			state = insn->state;
-
+			ret = apply_insn_hint(file, sec, func, insn, &state);
+			if (ret)
+				return ret;
 		} else
 			insn->state = state;