linux-kernel - [PATCH v5 18/30] objtool: Preserve alternatives order

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Message-ID: <20251119143247.3944213-19-alexandre.chartre@oracle.com>
Date: Wed, 19 Nov 2025 15:32:35 +0100
From: Alexandre Chartre <alexandre.chartre@...cle.com>
To: linux-kernel@...r.kernel.org, mingo@...nel.org, jpoimboe@...nel.org,
        peterz@...radead.org, david.laight.linux@...il.com
Cc: alexandre.chartre@...cle.com
Subject: [PATCH v5 18/30] objtool: Preserve alternatives order

Preserve the order in which alternatives are defined. Currently
objtool stores alternatives in a list in reverse order.

Signed-off-by: Alexandre Chartre <alexandre.chartre@...cle.com>
---
 tools/objtool/check.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 5bb932f211f6b..25839c3950a3c 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1942,6 +1942,7 @@ static int add_special_section_alts(struct objtool_file *file)
 	struct special_alt *special_alt, *tmp;
 	enum alternative_type alt_type;
 	struct alternative *alt;
+	struct alternative *a;
 
 	if (special_get_alts(file->elf, &special_alts))
 		return -1;
@@ -1994,9 +1995,20 @@ static int add_special_section_alts(struct objtool_file *file)
 		}
 
 		alt->insn = new_insn;
-		alt->next = orig_insn->alts;
 		alt->type = alt_type;
-		orig_insn->alts = alt;
+		alt->next = NULL;
+
+		/*
+		 * Store alternatives in the same order they have been
+		 * defined.
+		 */
+		if (!orig_insn->alts) {
+			orig_insn->alts = alt;
+		} else {
+			for (a = orig_insn->alts; a->next; a = a->next)
+				;
+			a->next = alt;
+		}
 
 		list_del(&special_alt->list);
 		free(special_alt);
-- 
2.43.5