From patchwork Fri Dec 3 10:42:27 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Amit Daniel Kachhap X-Patchwork-Id: 12654779 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 328C9C433F5 for ; Fri, 3 Dec 2021 10:43:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1380112AbhLCKrF (ORCPT ); Fri, 3 Dec 2021 05:47:05 -0500 Received: from foss.arm.com ([217.140.110.172]:47054 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1380105AbhLCKq4 (ORCPT ); Fri, 3 Dec 2021 05:46:56 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 77EF415A1; Fri, 3 Dec 2021 02:43:32 -0800 (PST) Received: from a077416.arm.com (unknown [10.163.33.180]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 89AF53F5A1; Fri, 3 Dec 2021 02:43:28 -0800 (PST) From: Amit Daniel Kachhap To: linux-kernel@vger.kernel.org Cc: Christoph Hellwig , Vincenzo Frascino , Kevin Brodsky , linux-fsdevel , kexec , Amit Daniel Kachhap , Paul Walmsley , Palmer Dabbelt , Albert Ou , linux-riscv Subject: [RFC PATCH 10/14] riscv/crash_dump: Use the new interface copy_oldmem_page_buf Date: Fri, 3 Dec 2021 16:12:27 +0530 Message-Id: <20211203104231.17597-11-amit.kachhap@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20211203104231.17597-1-amit.kachhap@arm.com> References: <20211203104231.17597-1-amit.kachhap@arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org The current interface copy_oldmem_page() passes user pointer without __user annotation and hence does unnecessary user/kernel pointer conversions during its implementation. Use the interface copy_oldmem_page_buf() to avoid this issue. Cc: Paul Walmsley Cc: Palmer Dabbelt Cc: Albert Ou Cc: linux-riscv Signed-off-by: Amit Daniel Kachhap --- arch/riscv/kernel/crash_dump.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) diff --git a/arch/riscv/kernel/crash_dump.c b/arch/riscv/kernel/crash_dump.c index 86cc0ada5752..3a8fadcd1278 100644 --- a/arch/riscv/kernel/crash_dump.c +++ b/arch/riscv/kernel/crash_dump.c @@ -9,20 +9,21 @@ #include /** - * copy_oldmem_page() - copy one page from old kernel memory + * copy_oldmem_page_buf() - copy one page from old kernel memory * @pfn: page frame number to be copied - * @buf: buffer where the copied page is placed + * @ubuf: user buffer where the copied page is placed; use copy_to_user() if + * this pointer is not NULL + * @kbuf: kernel buffer where the copied page is placed; use memcpy() if this + * pointer is not NULL * @csize: number of bytes to copy * @offset: offset in bytes into the page - * @userbuf: if set, @buf is in a user address space * - * This function copies one page from old kernel memory into buffer pointed by - * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes - * copied or negative error in case of failure. + * This function copies one page from old kernel memory into the buffer pointed + * by either @ubuf or @kbuf. Returns number of bytes copied or negative error in + * case of failure. */ -ssize_t copy_oldmem_page(unsigned long pfn, char *buf, - size_t csize, unsigned long offset, - int userbuf) +ssize_t copy_oldmem_page_buf(unsigned long pfn, char __user *ubuf, char *kbuf, + size_t csize, unsigned long offset) { void *vaddr; @@ -33,13 +34,13 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, if (!vaddr) return -ENOMEM; - if (userbuf) { - if (copy_to_user((char __user *)buf, vaddr + offset, csize)) { + if (ubuf) { + if (copy_to_user(ubuf, vaddr + offset, csize)) { memunmap(vaddr); return -EFAULT; } } else - memcpy(buf, vaddr + offset, csize); + memcpy(kbuf, vaddr + offset, csize); memunmap(vaddr); return csize;