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=-11.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 5EBAEC4741F for ; Wed, 4 Nov 2020 06:31:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0FBF722277 for ; Wed, 4 Nov 2020 06:31:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728532AbgKDGb6 (ORCPT ); Wed, 4 Nov 2020 01:31:58 -0500 Received: from mail.loongson.cn ([114.242.206.163]:40048 "EHLO loongson.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727323AbgKDGb5 (ORCPT ); Wed, 4 Nov 2020 01:31:57 -0500 Received: from [10.130.0.60] (unknown [113.200.148.30]) by mail.loongson.cn (Coremail) with SMTP id AQAAf9DxD9PVSqJfPnkFAA--.14168S3; Wed, 04 Nov 2020 14:31:52 +0800 (CST) Subject: Re: [PATCH v3 5/6] MIPS: Loongson64: SMP: Fix up play_dead jump indicator To: Tiezhu Yang , Thomas Bogendoerfer , Huacai Chen , Jiaxun Yang References: <1604387525-23400-1-git-send-email-yangtiezhu@loongson.cn> <1604387525-23400-6-git-send-email-yangtiezhu@loongson.cn> Cc: linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, Xuefeng Li , Lu Zeng , Jun Yi From: Jinyang He Message-ID: Date: Wed, 4 Nov 2020 14:31:49 +0800 User-Agent: Mozilla/5.0 (X11; Linux mips64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <1604387525-23400-6-git-send-email-yangtiezhu@loongson.cn> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CM-TRANSID: AQAAf9DxD9PVSqJfPnkFAA--.14168S3 X-Coremail-Antispam: 1UD129KBjvJXoW7ZF1UJw15KFWrGFykCFW8tFb_yoW8Zr1Dp3 9rAw17KFs8uF4UZFn5Jw1UJFWUJa9YqasxJFZFqr15Z3s0gw1Y9FySkr1rXa4xWF1vka40 qFyDurykCay7ArJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUvl14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26r1I6r4UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UM28EF7xvwVC2z280aVAFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Cr 1j6rxdM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj 6xIIjxv20xvE14v26r106r15McIj6I8E87Iv67AKxVW8JVWxJwAm72CE4IkC6x0Yz7v_Jr 0_Gr1lF7xvr2IY64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7Mxk0xIA0c2IEe2xFo4CE bIxvr21lc2xSY4AK67AK6r47MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r 4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF 67AKxVWUtVW8ZwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2I x0cI8IcVCY1x0267AKxVWUJVW8JwCI42IY6xAIw20EY4v20xvaj40_WFyUJVCq3wCI42IY 6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r1j6r4UYxBIdaVFxhVjvj DU0xZFpf9x0JUaoGdUUUUU= X-CM-SenderInfo: pkhmx0p1dqwqxorr0wxvrqhubq/ Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, all, On 11/03/2020 03:12 PM, Tiezhu Yang wrote: > In play_dead function, the whole 64-bit PC mailbox was used as a indicator > to determine if the master core had written boot jump information. > > However, after we introduced CSR mailsend, the hardware will not guarante > an atomic write for the 64-bit PC mailbox. Thus we have to use the lower > 32-bit which is written at the last as the jump indicator instead. > > Signed-off-by: Lu Zeng > Signed-off-by: Jun Yi > Signed-off-by: Tiezhu Yang > --- > > v2: No changes > v3: Update the commit message and comment > > arch/mips/loongson64/smp.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/mips/loongson64/smp.c b/arch/mips/loongson64/smp.c > index 736e98d..aa0cd72 100644 > --- a/arch/mips/loongson64/smp.c > +++ b/arch/mips/loongson64/smp.c > @@ -764,9 +764,10 @@ static void loongson3_type3_play_dead(int *state_addr) > "1: li %[count], 0x100 \n" /* wait for init loop */ > "2: bnez %[count], 2b \n" /* limit mailbox access */ > " addiu %[count], -1 \n" > - " ld %[initfunc], 0x20(%[base]) \n" /* get PC via mailbox */ I have some confusion here. Play_dead CPUs is always brought up by cpu_up(). On Loongson64, it calls loongson3_boot_secondary(). The value of startargs[0] is the address of smp_bootstrap() which is in CKSEG0 and a constant after the kernel is compiled. That means its value likes 0xffffffff8... and only the low 32bit is useful. As "lw" is sign-extended, could we replace "ld" with "lw" simply? Thanks, Jinyang > + " lw %[initfunc], 0x20(%[base]) \n" /* check lower 32-bit as jump indicator */ > " beqz %[initfunc], 1b \n" > " nop \n" > + " ld %[initfunc], 0x20(%[base]) \n" /* get PC (whole 64-bit) via mailbox */ > " ld $sp, 0x28(%[base]) \n" /* get SP via mailbox */ > " ld $gp, 0x30(%[base]) \n" /* get GP via mailbox */ > " ld $a1, 0x38(%[base]) \n"