From patchwork Fri Dec 3 10:42:28 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: 12654799 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 F08E0C433F5 for ; Fri, 3 Dec 2021 10:43:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352053AbhLCKrL (ORCPT ); Fri, 3 Dec 2021 05:47:11 -0500 Received: from foss.arm.com ([217.140.110.172]:47076 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1380141AbhLCKrA (ORCPT ); Fri, 3 Dec 2021 05:47:00 -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 F311A15AD; Fri, 3 Dec 2021 02:43:36 -0800 (PST) Received: from a077416.arm.com (unknown [10.163.33.180]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 1539C3F5A1; Fri, 3 Dec 2021 02:43:32 -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 , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , linuxppc Subject: [RFC PATCH 11/14] powerpc/crash_dump: Use the new interface copy_oldmem_page_buf Date: Fri, 3 Dec 2021 16:12:28 +0530 Message-Id: <20211203104231.17597-12-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: Michael Ellerman CC: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: linuxppc Signed-off-by: Amit Daniel Kachhap --- arch/powerpc/kernel/crash_dump.c | 33 ++++++++++++++++---------------- 1 file changed, 17 insertions(+), 16 deletions(-) diff --git a/arch/powerpc/kernel/crash_dump.c b/arch/powerpc/kernel/crash_dump.c index 5693e1c67c2b..a1c8a3a11694 100644 --- a/arch/powerpc/kernel/crash_dump.c +++ b/arch/powerpc/kernel/crash_dump.c @@ -68,33 +68,34 @@ void __init setup_kdump_trampoline(void) } #endif /* CONFIG_NONSTATIC_KERNEL */ -static size_t copy_oldmem_vaddr(void *vaddr, char *buf, size_t csize, - unsigned long offset, int userbuf) +static size_t copy_oldmem_vaddr(void *vaddr, char __user *ubuf, char *kbuf, + size_t csize, unsigned long offset) { - if (userbuf) { - if (copy_to_user((char __user *)buf, (vaddr + offset), csize)) + if (ubuf) { + if (copy_to_user(ubuf, (vaddr + offset), csize)) return -EFAULT; } else - memcpy(buf, (vaddr + offset), csize); + memcpy(kbuf, (vaddr + offset), csize); return csize; } /** - * copy_oldmem_page - copy one page from "oldmem" + * copy_oldmem_page_buf - copy one page from "oldmem" * @pfn: page frame number to be copied - * @buf: target memory address for the copy; this can be in kernel address - * space or user address space (see @userbuf) + * @ubuf: target user memory address for the copy; use copy_to_user() if this + * address is present + * @kbuf: target kernel memory address for the copy; use memcpy() if this + * address is present * @csize: number of bytes to copy * @offset: offset in bytes into the page (based on pfn) to begin the copy - * @userbuf: if set, @buf is in user address space, use copy_to_user(), - * otherwise @buf is in kernel address space, use memcpy(). * - * Copy a page from "oldmem". For this page, there is no pte mapped - * in the current kernel. We stitch up a pte, similar to kmap_atomic. + * Copy a page from "oldmem" into buffer pointed by either @ubuf or @kbuf. For + * this page, there is no pte mapped in the current kernel. We stitch up a pte, + * similar to kmap_atomic. */ -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; phys_addr_t paddr; @@ -107,10 +108,10 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, if (memblock_is_region_memory(paddr, csize)) { vaddr = __va(paddr); - csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf); + csize = copy_oldmem_vaddr(vaddr, ubuf, kbuf, csize, offset); } else { vaddr = ioremap_cache(paddr, PAGE_SIZE); - csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf); + csize = copy_oldmem_vaddr(vaddr, ubuf, kbuf, csize, offset); iounmap(vaddr); }