On Wed, 24 Sep 2025 09:59:58 +0200
Peter Zijlstra <peterz@infradead.org> wrote:
I would add a change log. Something like:
sizeof(long) is 4 or 8. Where 4 = 1 << 2 and 8 = 1 << 3.
Calculating shift to be 2 or 3 and then passing that variable into
(1 << shift) is the same as just using sizeof(long).
I blame lack of sleep for writing that code :-p
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
-- Steve
> ---
> kernel/unwind/user.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> --- a/kernel/unwind/user.c
> +++ b/kernel/unwind/user.c
> @@ -19,7 +19,6 @@ static int unwind_user_next_fp(struct un
> {
> 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 un
> 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) */
>