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 97a8415..9dcde79 100644 (file)
--- 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) */