From: Peter Zijlstra <peterz@infradead.org>
Date: Tue, 23 Sep 2025 11:04:09 +0000 (+0200)
Subject: unwind: Simplify unwind_user_next_fp() alignment check
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=5578534e4b92350995a20068f2e6ea3186c62d7f;p=thirdparty%2Fkernel%2Flinux.git

unwind: Simplify unwind_user_next_fp() alignment check

  2^log_2(n) == n

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://patch.msgid.link/20250924080119.497867836@infradead.org
---

diff --git a/kernel/unwind/user.c b/kernel/unwind/user.c
index 97a8415e3216f..9dcde797b5d93 100644
--- a/kernel/unwind/user.c
+++ b/kernel/unwind/user.c
@@ -19,7 +19,6 @@ static int unwind_user_next_fp(struct unwind_user_state *state)
 {
 	const struct unwind_user_frame *frame = &fp_frame;
 	unsigned long cfa, fp, ra;
-	unsigned int shift;
 
 	if (frame->use_fp) {
 		if (state->fp < state->sp)
@@ -37,8 +36,7 @@ static int unwind_user_next_fp(struct unwind_user_state *state)
 		return -EINVAL;
 
 	/* Make sure that the address is word aligned */
-	shift = sizeof(long) == 4 ? 2 : 3;
-	if (cfa & ((1 << shift) - 1))
+	if (cfa & (sizeof(long) - 1))
 		return -EINVAL;
 
 	/* Find the Return Address (RA) */