linux-kernel - [RFC][PATCH 2/6] objtool: Fix static

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Date:   Fri, 19 Feb 2021 21:43:02 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     jpoimboe@...hat.com, x86@...nel.org, pjt@...gle.com,
        mbenes@...e.cz, jgross@...e.com
Cc:     linux-kernel@...r.kernel.org, peterz@...radead.org
Subject: [RFC][PATCH 2/6] objtool: Fix static_call list generation

Currently objtool generates tail call entries in
add_jump_destination() but waits until validate_branch() to generate
the regular call entries, move these to add_call_destination() for
consistency.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 tools/objtool/check.c |   17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -974,6 +974,11 @@ static int add_call_destinations(struct
 		} else
 			insn->call_dest = reloc->sym;
 
+		if (insn->call_dest && insn->call_dest->static_call_tramp) {
+			list_add_tail(&insn->static_call_node,
+				      &file->static_call_list);
+		}
+
 		/*
 		 * Many compilers cannot disable KCOV with a function attribute
 		 * so they need a little help, NOP out any KCOV calls from noinstr
@@ -1701,6 +1706,9 @@ static int decode_sections(struct objtoo
 	if (ret)
 		return ret;
 
+	/*
+	 * Must be before add_{jump_call}_desetination.
+	 */
 	ret = read_static_call_tramps(file);
 	if (ret)
 		return ret;
@@ -1717,6 +1725,10 @@ static int decode_sections(struct objtoo
 	if (ret)
 		return ret;
 
+	/*
+	 * Must be before add_call_destination(); it changes INSN_CALL to
+	 * INSN_JUMP.
+	 */
 	ret = read_intra_function_calls(file);
 	if (ret)
 		return ret;
@@ -2659,11 +2671,6 @@ static int validate_branch(struct objtoo
 			if (dead_end_function(file, insn->call_dest))
 				return 0;
 
-			if (insn->type == INSN_CALL && insn->call_dest->static_call_tramp) {
-				list_add_tail(&insn->static_call_node,
-					      &file->static_call_list);
-			}
-
 			break;
 
 		case INSN_JUMP_CONDITIONAL: