From patchwork Tue Nov 30 22:08:08 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: andrey.konovalov@linux.dev X-Patchwork-Id: 12648287 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 992E3C433EF for ; Tue, 30 Nov 2021 22:13:42 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 51A2E6B0075; Tue, 30 Nov 2021 17:08:22 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4C9996B0088; Tue, 30 Nov 2021 17:08:22 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3B8576B0089; Tue, 30 Nov 2021 17:08:22 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0092.hostedemail.com [216.40.44.92]) by kanga.kvack.org (Postfix) with ESMTP id 2BC366B0075 for ; Tue, 30 Nov 2021 17:08:22 -0500 (EST) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id E6772853E9 for ; Tue, 30 Nov 2021 22:08:11 +0000 (UTC) X-FDA: 78866985582.05.6BF9F76 Received: from out1.migadu.com (out1.migadu.com [91.121.223.63]) by imf31.hostedemail.com (Postfix) with ESMTP id 2738A1046302 for ; Tue, 30 Nov 2021 22:07:59 +0000 (UTC) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1638310090; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=/6qJwit6ITW8lPGUAdTPjRxCn0EQ40SKku7cvq8gPsA=; b=Z4Yuz3BRckT0pZZtivLkslb47vrrWnkskR/i1AYmyXGZ6nnU6ad48vgnRdp4m8E/f+7DE4 n+d0qMciv/EuNLT+EhFYzdNjD6DuBFLdl0jdnhHG21fKR2Qdhlfm19buPMrJZXcdD3vdUI vDWH8ymk4nMxlLZUsj4ZdoJikhsjO2g= From: andrey.konovalov@linux.dev To: Marco Elver , Alexander Potapenko , Vincenzo Frascino , Catalin Marinas , Peter Collingbourne Cc: Andrey Konovalov , Dmitry Vyukov , Andrey Ryabinin , kasan-dev@googlegroups.com, Andrew Morton , linux-mm@kvack.org, Will Deacon , linux-arm-kernel@lists.infradead.org, Evgenii Stepanov , linux-kernel@vger.kernel.org, Andrey Konovalov Subject: [PATCH 26/31] kasan, page_alloc: allow skipping unpoisoning for HW_TAGS Date: Tue, 30 Nov 2021 23:08:08 +0100 Message-Id: In-Reply-To: References: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 2738A1046302 X-Stat-Signature: n4c41qd5g8btrn4rqw87k7zepi34th3a Authentication-Results: imf31.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=Z4Yuz3BR; spf=pass (imf31.hostedemail.com: domain of andrey.konovalov@linux.dev designates 91.121.223.63 as permitted sender) smtp.mailfrom=andrey.konovalov@linux.dev; dmarc=pass (policy=none) header.from=linux.dev X-HE-Tag: 1638310079-525561 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Andrey Konovalov This patch add a new GFP flag __GFP_SKIP_KASAN_UNPOISON that allows skipping KASAN poisoning for page_alloc allocations. The flag is only effective with HW_TAGS KASAN. This flag will be used by vmalloc code for page_alloc allocations backing vmalloc() mappings in the following patch. The reason to skip KASAN poisoning for these pages in page_alloc is because vmalloc code will be poisoning them instead. Signed-off-by: Andrey Konovalov --- include/linux/gfp.h | 13 +++++++++---- mm/page_alloc.c | 24 +++++++++++++++++------- 2 files changed, 26 insertions(+), 11 deletions(-) diff --git a/include/linux/gfp.h b/include/linux/gfp.h index dddd7597689f..a4c8ff3fbed1 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -54,9 +54,10 @@ struct vm_area_struct; #define ___GFP_THISNODE 0x200000u #define ___GFP_ACCOUNT 0x400000u #define ___GFP_ZEROTAGS 0x800000u -#define ___GFP_SKIP_KASAN_POISON 0x1000000u +#define ___GFP_SKIP_KASAN_UNPOISON 0x1000000u +#define ___GFP_SKIP_KASAN_POISON 0x2000000u #ifdef CONFIG_LOCKDEP -#define ___GFP_NOLOCKDEP 0x2000000u +#define ___GFP_NOLOCKDEP 0x4000000u #else #define ___GFP_NOLOCKDEP 0 #endif @@ -235,6 +236,9 @@ struct vm_area_struct; * %__GFP_ZEROTAGS zeroes memory tags at allocation time if the memory itself * is being zeroed (either via __GFP_ZERO or via init_on_alloc). * + * %__GFP_SKIP_KASAN_UNPOISON skips KASAN unpoisoning on page allocation. + * Currently only has an effect in HW tags mode. + * * %__GFP_SKIP_KASAN_POISON returns a page which does not need to be poisoned * on deallocation. Typically used for userspace pages. Currently only has an * effect in HW tags mode. @@ -243,13 +247,14 @@ struct vm_area_struct; #define __GFP_COMP ((__force gfp_t)___GFP_COMP) #define __GFP_ZERO ((__force gfp_t)___GFP_ZERO) #define __GFP_ZEROTAGS ((__force gfp_t)___GFP_ZEROTAGS) -#define __GFP_SKIP_KASAN_POISON ((__force gfp_t)___GFP_SKIP_KASAN_POISON) +#define __GFP_SKIP_KASAN_UNPOISON ((__force gfp_t)___GFP_SKIP_KASAN_UNPOISON) +#define __GFP_SKIP_KASAN_POISON ((__force gfp_t)___GFP_SKIP_KASAN_POISON) /* Disable lockdep for GFP context tracking */ #define __GFP_NOLOCKDEP ((__force gfp_t)___GFP_NOLOCKDEP) /* Room for N __GFP_FOO bits */ -#define __GFP_BITS_SHIFT (25 + IS_ENABLED(CONFIG_LOCKDEP)) +#define __GFP_BITS_SHIFT (26 + IS_ENABLED(CONFIG_LOCKDEP)) #define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1)) /** diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 4eb341351124..3afebc037fcd 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2381,6 +2381,21 @@ static bool check_new_pages(struct page *page, unsigned int order) return false; } +static inline bool should_skip_kasan_unpoison(gfp_t flags, bool init_tags) +{ + /* Don't skip if a software KASAN mode is enabled. */ + if (!IS_ENABLED(CONFIG_KASAN_HW_TAGS)) + return false; + + /* + * For hardware tag-based KASAN, skip if either: + * + * 1. Memory tags have already been cleared via tag_clear_highpage(). + * 2. Skipping has been requested via __GFP_SKIP_KASAN_UNPOISON. + */ + return init_tags || (flags & __GFP_SKIP_KASAN_UNPOISON); +} + inline void post_alloc_hook(struct page *page, unsigned int order, gfp_t gfp_flags) { @@ -2420,13 +2435,8 @@ inline void post_alloc_hook(struct page *page, unsigned int order, /* Note that memory is already initialized by the loop above. */ init = false; } - /* - * If either a software KASAN mode is enabled, or, - * in the case of hardware tag-based KASAN, - * if memory tags have not been cleared via tag_clear_highpage(). - */ - if (!IS_ENABLED(CONFIG_KASAN_HW_TAGS) || !init_tags) { - /* Mark shadow memory or set memory tags. */ + if (!should_skip_kasan_unpoison(gfp_flags, init_tags)) { + /* Unpoison shadow memory or set memory tags. */ kasan_unpoison_pages(page, order, init); /* Note that memory is already initialized by KASAN. */