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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EED71C76196 for ; Tue, 28 Mar 2023 12:15:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232060AbjC1MPr (ORCPT ); Tue, 28 Mar 2023 08:15:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48492 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232719AbjC1MPj (ORCPT ); Tue, 28 Mar 2023 08:15:39 -0400 Received: from loongson.cn (mail.loongson.cn [114.242.206.163]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 4745393E5; Tue, 28 Mar 2023 05:15:37 -0700 (PDT) Received: from loongson.cn (unknown [113.200.148.30]) by gateway (Coremail) with SMTP id _____8BxONlo2iJkeBYTAA--.29105S3; Tue, 28 Mar 2023 20:15:36 +0800 (CST) Received: from [10.130.0.102] (unknown [113.200.148.30]) by localhost.localdomain (Coremail) with SMTP id AQAAf8Dxjb5l2iJkMWQPAA--.35747S3; Tue, 28 Mar 2023 20:15:35 +0800 (CST) Subject: Re: [PATCH] LoongArch: Add kernel address sanitizer support To: Xi Ruoyao , Andrey Ryabinin , Jonathan Corbet , Huacai Chen , Andrew Morton Cc: Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , WANG Xuerui , Jiaxun Yang , kasan-dev@googlegroups.com, linux-doc@vger.kernel.org, linux-mm@kvack.org, loongarch@lists.linux.dev, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org References: <20230328111714.2056-1-zhangqing@loongson.cn> <9817aaa043e9f0ed964bd523773447bd64f6e2c0.camel@xry111.site> From: Qing Zhang Message-ID: <1c231587-3b70-22ab-d554-ebe3de407909@loongson.cn> Date: Tue, 28 Mar 2023 20:15:33 +0800 User-Agent: Mozilla/5.0 (X11; Linux mips64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <9817aaa043e9f0ed964bd523773447bd64f6e2c0.camel@xry111.site> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-CM-TRANSID: AQAAf8Dxjb5l2iJkMWQPAA--.35747S3 X-CM-SenderInfo: x2kd0wptlqwqxorr0wxvrqhubq/ X-Coremail-Antispam: 1Uk129KBjvJXoW7ArWDtw4rur15Gr1DuF1Dtrb_yoW8ZF4kpr ykJF15JrWrAr18Jr1qqw1DZryUXw1qq3W5Gr1DJFyrZw17Aryjgr4DXr1qgr1Dtr40gr15 Jr1UtF12vw1UJr7anT9S1TB71UUUUbUqnTZGkaVYY2UrUUUUj1kv1TuYvTs0mT0YCTnIWj qI5I8CrVACY4xI64kE6c02F40Ex7xfYxn0WfASr-VFAUDa7-sFnT9fnUUIcSsGvfJTRUUU bqxYFVCjjxCrM7AC8VAFwI0_Jr0_Gr1l1xkIjI8I6I8E6xAIw20EY4v20xvaj40_Wr0E3s 1l1IIY67AEw4v_Jrv_JF1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xv wVC0I7IYx2IY67AKxVW5JVW7JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwA2z4 x0Y4vEx4A2jsIE14v26r4UJVWxJr1l84ACjcxK6I8E87Iv6xkF7I0E14v26F4UJVW0owAa w2AFwI0_JF0_Jw1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqjxCEc2xF0cIa020Ex4CE44 I27wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_Jw0_WrylYx0Ex4A2 jsIE14v26r4j6F4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvEwIxGrwCYjI0SjxkI62 AI1cAE67vIY487MxkF7I0En4kS14v26r1q6r43MxAIw28IcxkI7VAKI48JMxC20s026xCa FVCjc4AY6r1j6r4UMxCIbckI1I0E14v26r4a6rW5MI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2 IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVW8ZVWrXwCIc40Y0x0EwIxGrwCI 42IY6xIIjxv20xvE14v26r1I6r4UMIIF0xvE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwCI42 IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcVC2z280 aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7IU8XTm3UUUUU== Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Ruoyao On 2023/3/28 下午7:39, Xi Ruoyao wrote: > On Tue, 2023-03-28 at 19:17 +0800, Qing Zhang wrote: > > /* snip */ > > >> -void * __init relocate_kernel(void) >> +unsigned long __init relocate_kernel(void) > > Why we must modify relocate_kernel for KASAN? When the CONFIG_RANDOMIZE_BASE is enabled, the kernel will be updated to a random new address. Kasan needs to call kasan_early_init before start_kernel. There are two situations: 1> After enabling CONFIG_RELOCATABLE, call kasan_early_init. 2> After CONFIG_RELOCATABLE is not enabled, call kasan_early_init. In order to prevent code redundancy and semantic problems caused by calling kasan_early_init (before jr a0) at the old PC. Thanks, -Qing > >>  { >>         unsigned long kernel_length; >>         unsigned long random_offset = 0; >>         void *location_new = _text; /* Default to original kernel start */ >> -       void *kernel_entry = start_kernel; /* Default to original kernel entry point */ >>         char *cmdline = early_ioremap(fw_arg1, COMMAND_LINE_SIZE); /* Boot command line is passed in fw_arg1 */ >> >>         strscpy(boot_command_line, cmdline, COMMAND_LINE_SIZE); >> @@ -190,9 +189,6 @@ void * __init relocate_kernel(void) >> >>                 reloc_offset += random_offset; >> >> -               /* Return the new kernel's entry point */ >> -               kernel_entry = RELOCATED_KASLR(start_kernel); >> - >>                 /* The current thread is now within the relocated kernel */ >>                 __current_thread_info = RELOCATED_KASLR(__current_thread_info); >> >> @@ -204,7 +200,7 @@ void * __init relocate_kernel(void) >> >>         relocate_absolute(random_offset); >> >> -       return kernel_entry; >> +       return random_offset; >