From patchwork Mon Jan 24 18:05:02 2022 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: 12722808 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7AFC0C433F5 for ; Mon, 24 Jan 2022 18:59:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Su6PuE6Pb4/XmvZZn+yCoTeDdnjCgPkKcNUJskhqJEM=; b=aL4yycUOxCTSQ4 AYeD43jJqla4SNvrBN1qalJdkvCQWLz6ciYJP3ddeya8WPG+2mRD4v0ZOujbeLP8AZ9BOXGHzRatv dHKOoOfykI6AS+fupdN+vxL7T3hEWNoPWlzEUTxGwJ6mJAy/OUU+pGzmxC3BQ7kcxd2FZqdun2rIL oXPxaZgycTUN97XCM4Vnlc8+NaZCoKlvK21QP3HL648bcgaGGsPYDPUwseq0m03/kb6N4S+mpGveF tJLzwsT4TzloOurAxiejsQce5xUJTM+2jikV7lly8W85jIrOjmCnQTuHlfehbI+n42zj1iVdWbRc2 Gm4tBdN2f+M2YmDGmunQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nC4Xs-004gb6-3O; Mon, 24 Jan 2022 18:58:29 +0000 Received: from out0.migadu.com ([2001:41d0:2:267::]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nC3jW-004NFo-9o for linux-arm-kernel@lists.infradead.org; Mon, 24 Jan 2022 18:06:28 +0000 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=1643047584; 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=hHzmzy1f4cPzWu7uvPj5X+wL96Wl9C2siP6FRJTw3ao=; b=jY5cVJPFt/ptbsYRXTc6vuGRUBbPx5oMoaY8mHH7OwI14bptco75enIZUjFeGwilR9/suj 8wNl6mTDG9Uwd6w8YCer7txBdVEaG2oZFihx5qH2s6Yc3OOcinXKzQNniR/J1Avpp9sqjQ 0CINeozLWY9PEFf9lbP51jFSj4Rc2JA= From: andrey.konovalov@linux.dev To: Andrew Morton Cc: Andrey Konovalov , Marco Elver , Alexander Potapenko , Dmitry Vyukov , Andrey Ryabinin , kasan-dev@googlegroups.com, linux-mm@kvack.org, Vincenzo Frascino , Catalin Marinas , Will Deacon , Mark Rutland , linux-arm-kernel@lists.infradead.org, Peter Collingbourne , Evgenii Stepanov , linux-kernel@vger.kernel.org, Andrey Konovalov Subject: [PATCH v6 28/39] kasan, page_alloc: allow skipping unpoisoning for HW_TAGS Date: Mon, 24 Jan 2022 19:05:02 +0100 Message-Id: <35c97d77a704f6ff971dd3bfe4be95855744108e.1643047180.git.andreyknvl@google.com> In-Reply-To: References: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220124_100626_708580_9A59755E X-CRM114-Status: GOOD ( 19.60 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Andrey Konovalov 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 a following patch. The reason to skip KASAN poisoning for these pages in page_alloc is because vmalloc code will be poisoning them instead. Also reword the comment for __GFP_SKIP_KASAN_POISON. Signed-off-by: Andrey Konovalov --- Changes v4->v5: - Cosmetic changes to __def_gfpflag_names_kasan and __GFP_BITS_SHIFT. Changes v3->v4: - Only define __GFP_SKIP_KASAN_POISON when CONFIG_KASAN_HW_TAGS is enabled. Changes v2->v3: - Update patch description. Signed-off-by: Andrey Konovalov --- include/linux/gfp.h | 21 +++++++++++++-------- include/trace/events/mmflags.h | 5 +++-- mm/page_alloc.c | 31 ++++++++++++++++++++++--------- 3 files changed, 38 insertions(+), 19 deletions(-) diff --git a/include/linux/gfp.h b/include/linux/gfp.h index 96f707931770..7303d1064460 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -55,12 +55,14 @@ struct vm_area_struct; #define ___GFP_ACCOUNT 0x400000u #define ___GFP_ZEROTAGS 0x800000u #ifdef CONFIG_KASAN_HW_TAGS -#define ___GFP_SKIP_KASAN_POISON 0x1000000u +#define ___GFP_SKIP_KASAN_UNPOISON 0x1000000u +#define ___GFP_SKIP_KASAN_POISON 0x2000000u #else +#define ___GFP_SKIP_KASAN_UNPOISON 0 #define ___GFP_SKIP_KASAN_POISON 0 #endif #ifdef CONFIG_LOCKDEP -#define ___GFP_NOLOCKDEP 0x2000000u +#define ___GFP_NOLOCKDEP 0x4000000u #else #define ___GFP_NOLOCKDEP 0 #endif @@ -241,22 +243,25 @@ struct vm_area_struct; * intended for optimization: setting memory tags at the same time as zeroing * memory has minimal additional performace impact. * - * %__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. + * %__GFP_SKIP_KASAN_UNPOISON makes KASAN skip unpoisoning on page allocation. + * Only effective in HW_TAGS mode. + * + * %__GFP_SKIP_KASAN_POISON makes KASAN skip poisoning on page deallocation. + * Typically, used for userspace pages. Only effective in HW_TAGS mode. */ #define __GFP_NOWARN ((__force gfp_t)___GFP_NOWARN) #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 (24 + \ - IS_ENABLED(CONFIG_KASAN_HW_TAGS) + \ +#define __GFP_BITS_SHIFT (24 + \ + 2 * IS_ENABLED(CONFIG_KASAN_HW_TAGS) + \ IS_ENABLED(CONFIG_LOCKDEP)) #define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1)) diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h index cb4520374e2c..134c45e62d91 100644 --- a/include/trace/events/mmflags.h +++ b/include/trace/events/mmflags.h @@ -52,8 +52,9 @@ {(unsigned long)__GFP_ZEROTAGS, "__GFP_ZEROTAGS"} \ #ifdef CONFIG_KASAN_HW_TAGS -#define __def_gfpflag_names_kasan \ - , {(unsigned long)__GFP_SKIP_KASAN_POISON, "__GFP_SKIP_KASAN_POISON"} +#define __def_gfpflag_names_kasan , \ + {(unsigned long)__GFP_SKIP_KASAN_POISON, "__GFP_SKIP_KASAN_POISON"}, \ + {(unsigned long)__GFP_SKIP_KASAN_UNPOISON, "__GFP_SKIP_KASAN_UNPOISON"} #else #define __def_gfpflag_names_kasan #endif diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 3af38e323391..94bfbc216ae9 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2395,6 +2395,26 @@ 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_GENERIC) || + IS_ENABLED(CONFIG_KASAN_SW_TAGS)) + return false; + + /* Skip, if hardware tag-based KASAN is not enabled. */ + if (!kasan_hw_tags_enabled()) + return true; + + /* + * With hardware tag-based KASAN enabled, 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) { @@ -2434,15 +2454,8 @@ 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_GENERIC) || - IS_ENABLED(CONFIG_KASAN_SW_TAGS) || - kasan_hw_tags_enabled() && !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. */