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 984ACC76196 for ; Wed, 29 Mar 2023 02:02:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229774AbjC2CCM (ORCPT ); Tue, 28 Mar 2023 22:02:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54904 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229745AbjC2CCF (ORCPT ); Tue, 28 Mar 2023 22:02:05 -0400 Received: from loongson.cn (mail.loongson.cn [114.242.206.163]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 1C356189; Tue, 28 Mar 2023 19:02:02 -0700 (PDT) Received: from loongson.cn (unknown [113.200.148.30]) by gateway (Coremail) with SMTP id _____8DxUOUZnCNklHsTAA--.29798S3; Wed, 29 Mar 2023 10:02:01 +0800 (CST) Received: from [10.130.0.102] (unknown [113.200.148.30]) by localhost.localdomain (Coremail) with SMTP id AQAAf8CxPL4XnCNkIQQQAA--.12984S3; Wed, 29 Mar 2023 10:02:01 +0800 (CST) Subject: Re: [PATCH] LoongArch: Add kernel address sanitizer support To: Huacai Chen Cc: Xi Ruoyao , Andrey Ryabinin , Jonathan Corbet , Andrew Morton , 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> <1c231587-3b70-22ab-d554-ebe3de407909@loongson.cn> From: Qing Zhang Message-ID: <9a6f11a3-d01c-e0c9-a4f3-47db25ce02f3@loongson.cn> Date: Wed, 29 Mar 2023 10:01:59 +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: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-CM-TRANSID: AQAAf8CxPL4XnCNkIQQQAA--.12984S3 X-CM-SenderInfo: x2kd0wptlqwqxorr0wxvrqhubq/ X-Coremail-Antispam: 1Uk129KBjvJXoW7uF43ur1UArykKF4xtw43Wrg_yoW8tw4Upr y8GF4rtw48Jr40vrs2q34Duryjv3Z2qw1agr4DK34rZ3sF9F98Kr4DWr13uF929r1j9F4Y vFWrtFWa934UJaDanT9S1TB71UUUUbUqnTZGkaVYY2UrUUUUj1kv1TuYvTs0mT0YCTnIWj qI5I8CrVACY4xI64kE6c02F40Ex7xfYxn0WfASr-VFAUDa7-sFnT9fnUUIcSsGvfJTRUUU bq8YFVCjjxCrM7AC8VAFwI0_Jr0_Gr1l1xkIjI8I6I8E6xAIw20EY4v20xvaj40_Wr0E3s 1l1IIY67AEw4v_Jrv_JF1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xv wVC0I7IYx2IY67AKxVW8JVW5JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwA2z4 x0Y4vEx4A2jsIE14v26F4j6r4UJwA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UM2kK e7AKxVWUAVWUtwAS0I0E0xvYzxvE52x082IY62kv0487Mc804VCY07AIYIkI8VC2zVCFFI 0UMc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUtVWrXwAv7VC2z280 aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcVAKI48JMxk0xIA0c2IEe2 xFo4CEbIxvr21lc7CjxVAaw2AFwI0_Jw0_GFyl42xK82IYc2Ij64vIr41l4I8I3I0E4IkC 6x0Yz7v_Jr0_Gr1l4IxYO2xFxVAFwI0_JF0_Jw1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s 026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a6rW5MIIYrxkI7VAKI48JMIIF 0xvE2Ix0cI8IcVAFwI0_JFI_Gr1lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j6F4UMIIF0x vE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv 6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxU2pVbDUUUU Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Huacai On 2023/3/29 上午8:22, Huacai Chen wrote: > On Tue, Mar 28, 2023 at 8:15 PM Qing Zhang wrote: >> >> 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. > In my opinion, you can call kasan_early_init before relocate_kernel in > head.S, then no redundancy. > It has no effect now, but kasan_early_init generally maps everything to a single page of zeroes in kasan area, if placed Before relocate_kernel, when the kernel was relocated, I worried that there were changes other than the memory layout. Thanks, - Qing > Huacai >> >> 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; >>> >>