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X-CSE-ConnectionGUID: KkNaI7E+TNmZ1CulPUPCSQ== X-CSE-MsgGUID: isoK9JiWR6Wzm/x8vTJXRQ== X-IronPort-AV: E=McAfee;i="6800,10657,11533"; a="68970664" X-IronPort-AV: E=Sophos;i="6.18,214,1751266800"; d="scan'208";a="68970664" 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: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Stat-Signature: ego16egjhtfjyctk6kokgjgugm4ypxhm X-Rspam-User: X-Rspamd-Queue-Id: D59131C000D X-Rspamd-Server: rspam05 X-HE-Tag: 1756153720-381723 X-HE-Meta: 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 IErJDbOF 3TCCszkxgxtbejP7wFYE07x/jKDMr8QYWS2OP9xQnQPJh3ZXcgA6UgI2IYe225MgPgzz2x7kQXAXKKUyjDxSS/sSbovY68zT2CT1CBqyxAJyxVERXpE3X5lDuRFZ0drhOPFV5U/pAG4XcmcBrPQRevspz72esrbAPRTpcvpgCpe7gia0W/WfcbA/gUtaMwV5UwUw9XMlaU2SltPHyFUKP4Swn4OahMiA2DXKGcPn6QApqR3wn88db2A5T2YqJBFZWylC+ 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: List-Subscribe: List-Unsubscribe: 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