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X-CSE-ConnectionGUID: lPSZMBohTV2trlAKQ/wX1Q== X-CSE-MsgGUID: 8MhK/5u4TNa2PRiqruv2Mg== X-IronPort-AV: E=McAfee;i="6700,10204,11394"; a="55401809" X-IronPort-AV: E=Sophos;i="6.15,188,1739865600"; d="scan'208";a="55401809" Received: from fmviesa009.fm.intel.com ([10.60.135.149]) by orvoesa103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Apr 2025 06:16:33 -0700 X-CSE-ConnectionGUID: TzYslCmYQFCBxN0Q9bAEvg== X-CSE-MsgGUID: AIqBIgH2RQGX8Ny4prod5A== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.15,188,1739865600"; d="scan'208";a="128157216" Received: from opintica-mobl1 (HELO wieczorr-mobl1.intel.com) ([10.245.245.50]) by fmviesa009-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Apr 2025 06:16:17 -0700 From: Maciej Wieczor-Retman To: hpa@zytor.com, hch@infradead.org, nick.desaulniers+lkml@gmail.com, kuan-ying.lee@canonical.com, masahiroy@kernel.org, samuel.holland@sifive.com, mingo@redhat.com, corbet@lwn.net, ryabinin.a.a@gmail.com, guoweikang.kernel@gmail.com, jpoimboe@kernel.org, ardb@kernel.org, vincenzo.frascino@arm.com, glider@google.com, kirill.shutemov@linux.intel.com, apopple@nvidia.com, samitolvanen@google.com, maciej.wieczor-retman@intel.com, kaleshsingh@google.com, jgross@suse.com, andreyknvl@gmail.com, scott@os.amperecomputing.com, tony.luck@intel.com, dvyukov@google.com, pasha.tatashin@soleen.com, ziy@nvidia.com, broonie@kernel.org, gatlin.newhouse@gmail.com, jackmanb@google.com, wangkefeng.wang@huawei.com, thiago.bauermann@linaro.org, tglx@linutronix.de, kees@kernel.org, akpm@linux-foundation.org, jason.andryuk@amd.com, snovitoll@gmail.com, xin@zytor.com, jan.kiszka@siemens.com, bp@alien8.de, rppt@kernel.org, peterz@infradead.org, pankaj.gupta@amd.com, thuth@redhat.com, andriy.shevchenko@linux.intel.com, joel.granados@kernel.org, kbingham@kernel.org, nicolas@fjasle.eu, mark.rutland@arm.com, surenb@google.com, catalin.marinas@arm.com, morbo@google.com, justinstitt@google.com, ubizjak@gmail.com, jhubbard@nvidia.com, urezki@gmail.com, dave.hansen@linux.intel.com, bhe@redhat.com, luto@kernel.org, baohua@kernel.org, nathan@kernel.org, will@kernel.org, brgerst@gmail.com Cc: llvm@lists.linux.dev, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, x86@kernel.org Subject: [PATCH v3 07/14] x86: KASAN raw shadow memory PTE init Date: Fri, 4 Apr 2025 15:14:11 +0200 Message-ID: X-Mailer: git-send-email 2.49.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 0C4A140007 X-Stat-Signature: 4msq8zzp4jjri36qi3pp83gh5jrsecnz X-Rspam-User: X-HE-Tag: 1743772593-940598 X-HE-Meta: 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 w8dqBogm hHIVkjeFTDTF76z9pxKvKQ6Art38tKsfD9DSsvHfIoQHtTgBJd5QvR0a9ZlQfeaJsTc31dNZAdgQFEw8HVcXOvrKVBzQi82neWEm/AAlgsyVmfVkK1FcEit6j22BrEuJ262Bwv8FPhaeQ13GPBkw39ZlmjB73eFkDqEG+arcRPeI8muWiLegLvYGRFgAGXBJcUmTQHjRynxmxjj222gued7X/yDDKc+/u2B+UMh1Ergls2/rzb4ftz6boYBUh1OHJB/t+ 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 0xE. 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; -- 2.49.0