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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 698BFC433F5 for ; Fri, 10 Sep 2021 01:01:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4A4C96113E for ; Fri, 10 Sep 2021 01:01:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233610AbhIJBCi (ORCPT ); Thu, 9 Sep 2021 21:02:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:49340 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234692AbhIJAYC (ORCPT ); Thu, 9 Sep 2021 20:24:02 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3995C611BD; Fri, 10 Sep 2021 00:22:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631233372; bh=vYoucGos+pTt0QUBpjP1CVCtT57uTeJsNcdvISAoRMc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NWvq4ZkEv2hlRXeqgTdMvVY2tSnE+BTtLZPEX9Hg9t9ei9qUXwXb2CIJd5linnWoZ F76IurN0uN3BZ18kGriV3CAN95uEBndxsC4UyvLJ3AVFAPTTNpzKD6jvQJFPNlnWdF 5CVtHgQXGBqOnu4nJyt5SjmOiWMlNtbjBD6CH8LBXZh2c8wS23wCBjWwH5UB8FyPjS 2MHvyR2bzSs0shOvGxuP0Yl2NwSkc3wcl7FB6OGS2bmwgkMXFblFg0Ew8drYPATh0z q0DqL6LoNxj0KLc1KLLS6GYGw4QUjn299Ckm0AtOBQA7npntCYAkXIED4S3EOkRmKp lnTDsdOPmtVrw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Christophe Leroy , Michael Ellerman , Sasha Levin , linuxppc-dev@lists.ozlabs.org Subject: [PATCH AUTOSEL 4.19 14/25] powerpc/32: indirect function call use bctrl rather than blrl in ret_from_kernel_thread Date: Thu, 9 Sep 2021 20:22:22 -0400 Message-Id: <20210910002234.176125-14-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210910002234.176125-1-sashal@kernel.org> References: <20210910002234.176125-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Christophe Leroy [ Upstream commit 113ec9ccc8049c3772f0eab46b62c5d6654c09f7 ] 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 Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/91b1d242525307ceceec7ef6e832bfbacdd4501b.1629436472.git.christophe.leroy@csgroup.eu Signed-off-by: Sasha Levin --- 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 26b3f853cbf6..0f40119cb5cb 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -477,10 +477,10 @@ 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 -- 2.30.2