From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.11]) (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 3A31827EFF1; Mon, 25 Aug 2025 20:28:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.11 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756153721; cv=none; b=DbLLKb4AzplTZvTV/g1kAQmJo4mToLzw+ADPxoct/S6Nlk+W6CbVkhtPe+iy98DYKbQDhXdKEF8baFB3vNGgfuUZKi5LNlaNHaFQODBp1Mz5XSCA0v+3nnROjnhFC9x886XjPxw3OmmjeMhkNoa8GKwfj9B3qdzWdXy81gNM7HA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756153721; c=relaxed/simple; bh=c7Af/YAFKCbSIcmDUGPF1EcBvvAVYWDWdLscrGxcJaU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cNxZsZ06JrrpWALow+NH3fGBlRiAQnoRF8nckqz791FBWZu3HbTJ3NPZCoDDFyptdifyPEmz6SdAYmRgVyTYDF47IvWhWHkLQQU8zNvo86cd01p6o4vgejts8fsgkmJYv9Ks4lceU6jQZ90LX78HHe5HriCb4PzMp7KEVZRlj3A= 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=jWfVcTob; arc=none smtp.client-ip=192.198.163.11 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="jWfVcTob" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1756153720; x=1787689720; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=c7Af/YAFKCbSIcmDUGPF1EcBvvAVYWDWdLscrGxcJaU=; b=jWfVcTobSQa3pb2zAV3FsO5yKSLWq/IR/r/Qjp4KxZjeGOXwAg7coVtb NAs2JGRbF9Gr0h1sqmZ3r091iC5rDv/Y8VpGRhZfbxOeeO7ctyxhTgZ0l 0cTLKRQfr+ese42oz/1hFM7ZZLyLHoO/QdWjEa4/jmOj4F01Utdj0tbZ4 ZTPPL1qLbEARiHxN29QHJfMnqXyrw3OHiQ/QKKiZ7fr40FdB02LAJX9s4 ad/Z3N+cQl9PaKO2BVZ7PUyb8U8I6Ekh0nmf3eBY5LZLuYhqkq/OPDmHC MyhF4LZSfdIf0OFRdeFDujBIzkKuFaOtTXCutXlC9j7lneVCYU83mnBkV A==; X-CSE-ConnectionGUID: 8DZ+ZIEpTZCd+tGh5ED3NA== X-CSE-MsgGUID: oEkizznNTm2tUvyKjGZKzg== X-IronPort-AV: E=McAfee;i="6800,10657,11533"; a="68970649" X-IronPort-AV: E=Sophos;i="6.18,214,1751266800"; d="scan'208";a="68970649" Received: from fmviesa008.fm.intel.com ([10.60.135.148]) by fmvoesa105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Aug 2025 13:28:39 -0700 X-CSE-ConnectionGUID: ZdrF+c9oTnqXBOaj3/bbCw== X-CSE-MsgGUID: b88EEwdzTV2GCqGXKxP8lQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.18,214,1751266800"; d="scan'208";a="169780469" Received: from bergbenj-mobl1.ger.corp.intel.com (HELO wieczorr-mobl1.intel.com) ([10.245.245.6]) by fmviesa008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Aug 2025 13:28:20 -0700 From: Maciej Wieczor-Retman To: sohil.mehta@intel.com, baohua@kernel.org, david@redhat.com, kbingham@kernel.org, weixugc@google.com, Liam.Howlett@oracle.com, alexandre.chartre@oracle.com, kas@kernel.org, mark.rutland@arm.com, trintaeoitogc@gmail.com, axelrasmussen@google.com, yuanchu@google.com, joey.gouly@arm.com, samitolvanen@google.com, joel.granados@kernel.org, graf@amazon.com, vincenzo.frascino@arm.com, kees@kernel.org, ardb@kernel.org, thiago.bauermann@linaro.org, glider@google.com, thuth@redhat.com, kuan-ying.lee@canonical.com, pasha.tatashin@soleen.com, nick.desaulniers+lkml@gmail.com, vbabka@suse.cz, kaleshsingh@google.com, justinstitt@google.com, catalin.marinas@arm.com, alexander.shishkin@linux.intel.com, samuel.holland@sifive.com, dave.hansen@linux.intel.com, corbet@lwn.net, xin@zytor.com, dvyukov@google.com, tglx@linutronix.de, scott@os.amperecomputing.com, jason.andryuk@amd.com, morbo@google.com, nathan@kernel.org, lorenzo.stoakes@oracle.com, mingo@redhat.com, brgerst@gmail.com, kristina.martsenko@arm.com, bigeasy@linutronix.de, luto@kernel.org, jgross@suse.com, jpoimboe@kernel.org, urezki@gmail.com, mhocko@suse.com, ada.coupriediaz@arm.com, hpa@zytor.com, maciej.wieczor-retman@intel.com, leitao@debian.org, peterz@infradead.org, wangkefeng.wang@huawei.com, surenb@google.com, ziy@nvidia.com, smostafa@google.com, ryabinin.a.a@gmail.com, ubizjak@gmail.com, jbohac@suse.cz, broonie@kernel.org, akpm@linux-foundation.org, guoweikang.kernel@gmail.com, rppt@kernel.org, pcc@google.com, jan.kiszka@siemens.com, nicolas.schier@linux.dev, will@kernel.org, andreyknvl@gmail.com, jhubbard@nvidia.com, bp@alien8.de Cc: x86@kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, llvm@lists.linux.dev, linux-kbuild@vger.kernel.org, kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH v5 09/19] x86: KASAN raw shadow memory PTE init Date: Mon, 25 Aug 2025 22:24:34 +0200 Message-ID: <9a7958543abababa30d534c44ba2f26d6bd692d6.1756151769.git.maciej.wieczor-retman@intel.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit In KASAN's generic mode the default value in shadow memory is zero. During initialization of shadow memory pages they are allocated and zeroed. In KASAN's tag-based mode the default tag for the arm64 architecture is 0xFE which corresponds to any memory that should not be accessed. On x86 (where tags are 4-bit wide instead of 8-bit wide) that tag is 0xE so during the initializations all the bytes in shadow memory pages should be filled with it. Use memblock_alloc_try_nid_raw() instead of memblock_alloc_try_nid() to avoid zeroing out the memory so it can be set with the KASAN invalid tag. Signed-off-by: Maciej Wieczor-Retman --- Changelog v2: - Remove dense mode references, use memset() instead of kasan_poison(). arch/x86/mm/kasan_init_64.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c index 0539efd0d216..e8a451cafc8c 100644 --- a/arch/x86/mm/kasan_init_64.c +++ b/arch/x86/mm/kasan_init_64.c @@ -34,6 +34,18 @@ static __init void *early_alloc(size_t size, int nid, bool should_panic) return ptr; } +static __init void *early_raw_alloc(size_t size, int nid, bool should_panic) +{ + void *ptr = memblock_alloc_try_nid_raw(size, size, + __pa(MAX_DMA_ADDRESS), MEMBLOCK_ALLOC_ACCESSIBLE, nid); + + if (!ptr && should_panic) + panic("%pS: Failed to allocate page, nid=%d from=%lx\n", + (void *)_RET_IP_, nid, __pa(MAX_DMA_ADDRESS)); + + return ptr; +} + static void __init kasan_populate_pmd(pmd_t *pmd, unsigned long addr, unsigned long end, int nid) { @@ -63,8 +75,9 @@ static void __init kasan_populate_pmd(pmd_t *pmd, unsigned long addr, if (!pte_none(*pte)) continue; - p = early_alloc(PAGE_SIZE, nid, true); - entry = pfn_pte(PFN_DOWN(__pa(p)), PAGE_KERNEL); + p = early_raw_alloc(PAGE_SIZE, nid, true); + memset(p, PAGE_SIZE, KASAN_SHADOW_INIT); + entry = pfn_pte(PFN_DOWN(__pa_nodebug(p)), PAGE_KERNEL); set_pte_at(&init_mm, addr, pte, entry); } while (pte++, addr += PAGE_SIZE, addr != end); } @@ -436,7 +449,7 @@ void __init kasan_init(void) * it may contain some garbage. Now we can clear and write protect it, * since after the TLB flush no one should write to it. */ - memset(kasan_early_shadow_page, 0, PAGE_SIZE); + memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE); for (i = 0; i < PTRS_PER_PTE; i++) { pte_t pte; pgprot_t prot; -- 2.50.1