From nobody Sun Dec 14 21:33:18 2025 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.20]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 19E2321639D; Tue, 4 Feb 2025 17:35:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.20 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738690528; cv=none; b=IPGVCSPKemz2Etje4MVpBaocKnU0NCr2zBxIOYCgT6cnAPqjUc9avK+88P7J4WX6QD9KCNpUHPkLEElcIhOAIHKF2eaLzdnO/WjZ0yeMaUZMu3k8pv5Ww6jPp56zXBlfrOYp1/V2FDY7zEmuIbYC/iZO4NGm8w8EUKer1zcJ4nM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738690528; c=relaxed/simple; bh=7SPlp9QEiWP+nB12GdV91yF1dqiTepZdICL7iZuq4h4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=i06K4oQXEGZpNJmPrXSl/FQCA5et3tVM1kFH7KhiQUyJzddQPI8JAqR7XXIfh1ji3y/SOKRb4pZaTGpzfkTwHJfc1hW+JoVDdqh3ge08l26rIW81XZpox+KFBbPe0d/nhuFc5Xr3MTMjIka+y5cLr6/ezIceuzBm/0P2B341F6Y= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=mpFAEIXA; arc=none smtp.client-ip=198.175.65.20 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="mpFAEIXA" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1738690527; x=1770226527; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=7SPlp9QEiWP+nB12GdV91yF1dqiTepZdICL7iZuq4h4=; b=mpFAEIXAsrrIMBAcnIvCKJz0uXT/PV3jYGdsm2nGrycSggR92krYDUDV z60eDyZ65u18zUxm1kRCJcpBr3p+37+AlhMOZ0EEIoRxJ26Mb+qdvqGbc YA/Mof5ZB8+G+LYxLDwTGj4mODCPKpqA2+eQqGH050Su+kuJD7qhZrpBR 6l4dmgLhYm8P+2Yf4UJoZhByx7cJweIzinBUzOOiF2NCADNz6VVF2dPtL ENh8gKGRbgQBLcnB0plRnGQwdOa0s2XrL8oysy4Jyxi7WlC+rG2d+HdRy uMxJtn774w/BI47RG4J1YLPe5nTY7l44Vh5BRxkmYQCuZnQ1ZnZocaT0n g==; X-CSE-ConnectionGUID: 7/LRegh0TN+f0pdyn8H7DQ== X-CSE-MsgGUID: 6VXRX2c/SgS1AhAUeHEvJQ== X-IronPort-AV: E=McAfee;i="6700,10204,11336"; a="38930508" X-IronPort-AV: E=Sophos;i="6.13,259,1732608000"; d="scan'208";a="38930508" Received: from orviesa001.jf.intel.com ([10.64.159.141]) by orvoesa112.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Feb 2025 09:35:25 -0800 X-CSE-ConnectionGUID: /sEOqI4kSuqYrX4FgQuozA== X-CSE-MsgGUID: zBO7dwN1RyyrRSQp4bH21Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.12,224,1728975600"; d="scan'208";a="147866447" Received: from mjarzebo-mobl1.ger.corp.intel.com (HELO wieczorr-mobl1.intel.com) ([10.245.244.61]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Feb 2025 09:35:14 -0800 From: Maciej Wieczor-Retman To: luto@kernel.org, xin@zytor.com, kirill.shutemov@linux.intel.com, palmer@dabbelt.com, tj@kernel.org, andreyknvl@gmail.com, brgerst@gmail.com, ardb@kernel.org, dave.hansen@linux.intel.com, jgross@suse.com, will@kernel.org, akpm@linux-foundation.org, arnd@arndb.de, corbet@lwn.net, maciej.wieczor-retman@intel.com, dvyukov@google.com, richard.weiyang@gmail.com, ytcoode@gmail.com, tglx@linutronix.de, hpa@zytor.com, seanjc@google.com, paul.walmsley@sifive.com, aou@eecs.berkeley.edu, justinstitt@google.com, jason.andryuk@amd.com, glider@google.com, ubizjak@gmail.com, jannh@google.com, bhe@redhat.com, vincenzo.frascino@arm.com, rafael.j.wysocki@intel.com, ndesaulniers@google.com, mingo@redhat.com, catalin.marinas@arm.com, junichi.nomura@nec.com, nathan@kernel.org, ryabinin.a.a@gmail.com, dennis@kernel.org, bp@alien8.de, kevinloughlin@google.com, morbo@google.com, dan.j.williams@intel.com, julian.stecklina@cyberus-technology.de, peterz@infradead.org, cl@linux.com, kees@kernel.org Cc: kasan-dev@googlegroups.com, x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, llvm@lists.linux.dev, linux-doc@vger.kernel.org Subject: [PATCH 04/15] kasan: arm64: x86: risc-v: Make special tags arch specific Date: Tue, 4 Feb 2025 18:33:45 +0100 Message-ID: X-Mailer: git-send-email 2.47.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" KASAN's tag-based mode defines multiple special tag values. They're reserved for: - Native kernel value. On arm64 it's 0xFF and it causes an early return in the tag checking function. - Invalid value. 0xFE marks an area as freed / unallocated. It's also the value that is used to initialize regions of shadow memory. - Max value. 0xFD is the highest value that can be randomly generated for a new tag. Metadata macro is also defined: - Tag width equal to 8. Tag-based mode on x86 is going to use 4 bit wide tags so all the above values need to be changed accordingly. Make tags arch specific for x86, risc-v and arm64. On x86 the values just lose the top 4 bits. Replace hardcoded kernel tag value and tag width with macros in KASAN's non-arch specific code. Signed-off-by: Maciej Wieczor-Retman Acked-by: Palmer Dabbelt # RISC-V --- MAINTAINERS | 2 +- arch/arm64/include/asm/kasan-tags.h | 9 +++++++++ arch/riscv/include/asm/kasan-tags.h | 12 ++++++++++++ arch/riscv/include/asm/kasan.h | 4 ---- arch/x86/include/asm/kasan-tags.h | 9 +++++++++ include/linux/kasan-tags.h | 12 +++++++++++- include/linux/kasan.h | 4 +++- include/linux/mm.h | 6 +++--- include/linux/page-flags-layout.h | 7 +------ 9 files changed, 49 insertions(+), 16 deletions(-) create mode 100644 arch/arm64/include/asm/kasan-tags.h create mode 100644 arch/riscv/include/asm/kasan-tags.h create mode 100644 arch/x86/include/asm/kasan-tags.h diff --git a/MAINTAINERS b/MAINTAINERS index b878ddc99f94..45671faa3b6f 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -12227,7 +12227,7 @@ L: kasan-dev@googlegroups.com S: Maintained B: https://bugzilla.kernel.org/buglist.cgi?component=3DSanitizers&product= =3DMemory%20Management F: Documentation/dev-tools/kasan.rst -F: arch/*/include/asm/*kasan.h +F: arch/*/include/asm/*kasan*.h F: arch/*/mm/kasan_init* F: include/linux/kasan*.h F: lib/Kconfig.kasan diff --git a/arch/arm64/include/asm/kasan-tags.h b/arch/arm64/include/asm/k= asan-tags.h new file mode 100644 index 000000000000..9e835da95f6b --- /dev/null +++ b/arch/arm64/include/asm/kasan-tags.h @@ -0,0 +1,9 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_KASAN_TAGS_H +#define __ASM_KASAN_TAGS_H + +#define KASAN_TAG_KERNEL 0xFF /* native kernel pointers tag */ + +#define KASAN_TAG_WIDTH 8 + +#endif /* ASM_KASAN_TAGS_H */ diff --git a/arch/riscv/include/asm/kasan-tags.h b/arch/riscv/include/asm/k= asan-tags.h new file mode 100644 index 000000000000..83d7dcc8af74 --- /dev/null +++ b/arch/riscv/include/asm/kasan-tags.h @@ -0,0 +1,12 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_KASAN_TAGS_H +#define __ASM_KASAN_TAGS_H + +#ifdef CONFIG_KASAN_SW_TAGS +#define KASAN_TAG_KERNEL 0x7f /* native kernel pointers tag */ +#endif + +#define KASAN_TAG_WIDTH 8 + +#endif /* ASM_KASAN_TAGS_H */ + diff --git a/arch/riscv/include/asm/kasan.h b/arch/riscv/include/asm/kasan.h index f6b378ba936d..27938e0d5233 100644 --- a/arch/riscv/include/asm/kasan.h +++ b/arch/riscv/include/asm/kasan.h @@ -41,10 +41,6 @@ =20 #define KASAN_SHADOW_OFFSET _AC(CONFIG_KASAN_SHADOW_OFFSET, UL) =20 -#ifdef CONFIG_KASAN_SW_TAGS -#define KASAN_TAG_KERNEL 0x7f /* native kernel pointers tag */ -#endif - #define arch_kasan_set_tag(addr, tag) __tag_set(addr, tag) #define arch_kasan_reset_tag(addr) __tag_reset(addr) #define arch_kasan_get_tag(addr) __tag_get(addr) diff --git a/arch/x86/include/asm/kasan-tags.h b/arch/x86/include/asm/kasan= -tags.h new file mode 100644 index 000000000000..68ba385bc75c --- /dev/null +++ b/arch/x86/include/asm/kasan-tags.h @@ -0,0 +1,9 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_KASAN_TAGS_H +#define __ASM_KASAN_TAGS_H + +#define KASAN_TAG_KERNEL 0xF /* native kernel pointers tag */ + +#define KASAN_TAG_WIDTH 4 + +#endif /* ASM_KASAN_TAGS_H */ diff --git a/include/linux/kasan-tags.h b/include/linux/kasan-tags.h index e07c896f95d3..b4aacfa8709b 100644 --- a/include/linux/kasan-tags.h +++ b/include/linux/kasan-tags.h @@ -2,7 +2,17 @@ #ifndef _LINUX_KASAN_TAGS_H #define _LINUX_KASAN_TAGS_H =20 -#include +#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) +#include +#endif + +#ifdef CONFIG_KASAN_SW_TAGS_DENSE +#define KASAN_TAG_WIDTH 4 +#endif + +#ifndef KASAN_TAG_WIDTH +#define KASAN_TAG_WIDTH 0 +#endif =20 #ifndef KASAN_TAG_KERNEL #define KASAN_TAG_KERNEL 0xFF /* native kernel pointers tag */ diff --git a/include/linux/kasan.h b/include/linux/kasan.h index 5a3e9bec21c2..83146367170a 100644 --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -88,7 +88,9 @@ static inline u8 kasan_get_shadow_tag(const void *addr) =20 #ifdef CONFIG_KASAN_SW_TAGS /* This matches KASAN_TAG_INVALID. */ -#define KASAN_SHADOW_INIT 0xFE +#ifndef KASAN_SHADOW_INIT +#define KASAN_SHADOW_INIT KASAN_TAG_INVALID +#endif #else #define KASAN_SHADOW_INIT 0 #endif diff --git a/include/linux/mm.h b/include/linux/mm.h index 61fff5d34ed5..ddca2f63a5f6 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1813,7 +1813,7 @@ static inline u8 page_kasan_tag(const struct page *pa= ge) =20 if (kasan_enabled()) { tag =3D (page->flags >> KASAN_TAG_PGSHIFT) & KASAN_TAG_MASK; - tag ^=3D 0xff; + tag ^=3D KASAN_TAG_KERNEL; } =20 return tag; @@ -1826,7 +1826,7 @@ static inline void page_kasan_tag_set(struct page *pa= ge, u8 tag) if (!kasan_enabled()) return; =20 - tag ^=3D 0xff; + tag ^=3D KASAN_TAG_KERNEL; old_flags =3D READ_ONCE(page->flags); do { flags =3D old_flags; @@ -1845,7 +1845,7 @@ static inline void page_kasan_tag_reset(struct page *= page) =20 static inline u8 page_kasan_tag(const struct page *page) { - return 0xff; + return KASAN_TAG_KERNEL; } =20 static inline void page_kasan_tag_set(struct page *page, u8 tag) { } diff --git a/include/linux/page-flags-layout.h b/include/linux/page-flags-l= ayout.h index 7d79818dc065..ac3576f409ad 100644 --- a/include/linux/page-flags-layout.h +++ b/include/linux/page-flags-layout.h @@ -3,6 +3,7 @@ #define PAGE_FLAGS_LAYOUT_H =20 #include +#include #include =20 /* @@ -72,12 +73,6 @@ #define NODE_NOT_IN_PAGE_FLAGS 1 #endif =20 -#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) -#define KASAN_TAG_WIDTH 8 -#else -#define KASAN_TAG_WIDTH 0 -#endif - #ifdef CONFIG_NUMA_BALANCING #define LAST__PID_SHIFT 8 #define LAST__PID_MASK ((1 << LAST__PID_SHIFT)-1) --=20 2.47.1