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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 2B45CC433B4 for ; Mon, 12 Apr 2021 08:09:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 01E9B61249 for ; Mon, 12 Apr 2021 08:09:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237213AbhDLIJi (ORCPT ); Mon, 12 Apr 2021 04:09:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55560 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237194AbhDLIJf (ORCPT ); Mon, 12 Apr 2021 04:09:35 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4B791C06138C for ; Mon, 12 Apr 2021 01:09:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=di4C6bbSl7iLJMkDo7XO8ZICGg5xRWGqLb1m8Rukv20=; b=YbnF5/GCNEslzNuBs5qK0QChkY 4uR2tlI+pJM2mlI4nY0EYfLtOv2DaYf8ETEJq1eLyxCAxq9TGczM8rCp5BGd+Pp07cRAxuXEjm3MH d511RbZdsZe/RF4L6N3ZM5JcGlgKNmsxldb1Ha6aZQlpgGBPRANGEpj5sE2FBpCGyvwTtpMzZqkAu TtunDAx5SH1+UnF7hGsF/IcAodYOGskfZE8U6c2QauhaJGYKoIil9rdGy+alOdxpfNZvDuVLiCUkw kAxBpkAmmy3G1hS15fLPpSpz9pVJj0TFx1VACeorabu44in+T0zAp4K5PJOEAV7dZYkdWPeoJ/9DV FT+b42rw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1lVrcl-003yd5-5N; Mon, 12 Apr 2021 08:08:49 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 7766E3001FF; Mon, 12 Apr 2021 10:08:44 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 3F6B025F21531; Mon, 12 Apr 2021 10:08:44 +0200 (CEST) Message-ID: <20210412080611.769864829@infradead.org> User-Agent: quilt/0.66 Date: Mon, 12 Apr 2021 10:00:16 +0200 From: Peter Zijlstra To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, boris.ostrovsky@oracle.com, jgross@suse.com, sstabellini@kernel.org, x86@kernel.org, jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com, rodrigo.vivi@intel.com, chris@chris-wilson.co.uk, intel-gfx@lists.freedesktop.org, linux-mm@kvack.org, keescook@chromium.org, hch@lst.de Subject: [PATCH 4/7] mm: Introduce verify_page_range() References: <20210412080012.357146277@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Introduce and EXPORT a read-only counterpart to apply_to_page_range(). It only exposes the PTE value, not a pointer to the pagetables itself and is thus quite a bit safer to export. A number of apply_to_page_range() users can be converted to this primitive. Signed-off-by: Peter Zijlstra (Intel) --- include/linux/mm.h | 4 ++++ mm/memory.c | 24 ++++++++++++++++++++++++ 2 files changed, 28 insertions(+) --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2876,6 +2876,10 @@ extern int apply_to_page_range(struct mm extern int apply_to_existing_page_range(struct mm_struct *mm, unsigned long address, unsigned long size, pte_fn_t fn, void *data); +extern int verify_page_range(struct mm_struct *mm, + unsigned long addr, unsigned long size, + int (*fn)(pte_t pte, unsigned long addr, void *data), + void *data); extern void init_mem_debugging_and_hardening(void); #ifdef CONFIG_PAGE_POISONING --- a/mm/memory.c +++ b/mm/memory.c @@ -2559,6 +2559,30 @@ int apply_to_existing_page_range(struct return __apply_to_page_range(mm, addr, size, fn, data, false); } +struct vpr_data { + int (*fn)(pte_t pte, unsigned long addr, void *data); + void *data; +}; + +static int vpr_fn(pte_t *pte, unsigned long addr, void *data) +{ + struct vpr_data *vpr = data; + return vpr->fn(*pte, addr, vpr->data); +} + +int verify_page_range(struct mm_struct *mm, + unsigned long addr, unsigned long size, + int (*fn)(pte_t pte, unsigned long addr, void *data), + void *data) +{ + struct vpr_data vpr = { + .fn = fn, + .data = data, + }; + return apply_to_page_range(mm, addr, size, vpr_fn, &vpr); +} +EXPORT_SYMBOL_GPL(verify_page_range); + /* * handle_pte_fault chooses page fault handler according to an entry which was * read non-atomically. Before making any commitment, on those architectures