From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 16D3FC432BE for ; Fri, 20 Aug 2021 05:16:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F0E0760F92 for ; Fri, 20 Aug 2021 05:16:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235904AbhHTFQt (ORCPT ); Fri, 20 Aug 2021 01:16:49 -0400 Received: from pegase2.c-s.fr ([93.17.235.10]:39341 "EHLO pegase2.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233951AbhHTFQr (ORCPT ); Fri, 20 Aug 2021 01:16:47 -0400 Received: from localhost (mailhub3.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4GrVGZ54MGz9sVZ; Fri, 20 Aug 2021 07:16:06 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase2.c-s.fr ([172.26.127.65]) by localhost (pegase2.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ATiTfI51WLBX; Fri, 20 Aug 2021 07:16:06 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4GrVGZ49dvz9sVF; Fri, 20 Aug 2021 07:16:06 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 6E0738B76A; Fri, 20 Aug 2021 07:16:06 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id Cgy46c8AJQ5G; Fri, 20 Aug 2021 07:16:06 +0200 (CEST) Received: from po9473vm.idsi0.si.c-s.fr (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 3AFB68B773; Fri, 20 Aug 2021 07:16:06 +0200 (CEST) Received: by po9473vm.idsi0.si.c-s.fr (Postfix, from userid 0) id EAB9466977; Fri, 20 Aug 2021 05:16:05 +0000 (UTC) Message-Id: <91b1d242525307ceceec7ef6e832bfbacdd4501b.1629436472.git.christophe.leroy@csgroup.eu> From: Christophe Leroy Subject: [PATCH] powerpc/32: indirect function call use bctrl rather than blrl in ret_from_kernel_thread To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Date: Fri, 20 Aug 2021 05:16:05 +0000 (UTC) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Copied from commit 89bbe4c798bc ("powerpc/64: indirect function call use bctrl rather than blrl in ret_from_kernel_thread") blrl is not recommended to use as an indirect function call, as it may corrupt the link stack predictor. This is not a performance critical path but this should be fixed for consistency. Signed-off-by: Christophe Leroy --- arch/powerpc/kernel/entry_32.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index 0273a1349006..61fdd53cdd9a 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -161,10 +161,10 @@ ret_from_fork: ret_from_kernel_thread: REST_NVGPRS(r1) bl schedule_tail - mtlr r14 + mtctr r14 mr r3,r15 PPC440EP_ERR42 - blrl + bctrl li r3,0 b ret_from_syscall -- 2.25.0