From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 13D6E3DA7FC for ; Thu, 25 Jun 2026 11:30:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782387059; cv=none; b=qXE6TCJxerABskvoUXkeLu5AqRHmLMrqRxPQGv8Z1Q1riT1Qsmr/AaydFi/EAFOLy1OsvfCqu+EWQE3tpb8i9m+JBWsCscYoaPQWomDfYED6MoUvtjYhO8dNQzMZm4CRgZ/1fheL9ZcS3UrTZCutQZLVHaEcGXd1TTr8gsewu/g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782387059; c=relaxed/simple; bh=qIVB6gHmZfbfjR8XMIsltlHaNah8ksCbKAdOfhqwEPs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nIc0P6z7YD3aQDZUBUpw8Js/IreDWD6UpYxmUTDuXFjcp3OXovh5Q12smO+UxtuSvqtiVPBCrdRfYVlny5sQmfLcs50mgEPyDJC3CpzVVUi5xmZgFpdDn9Ix8WB/XHSTf44svgl2/r9VW1sDi6y7Q6shv8IuOXFi62/nxfjhGQs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=fGeVw/tc; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="fGeVw/tc" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E477632C7; Thu, 25 Jun 2026 04:30:52 -0700 (PDT) Received: from cesw-amp-gbt-1s-m12830-01.blr.arm.com (cesw-amp-gbt-1s-m12830-01.blr.arm.com [10.164.195.31]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id CF1233F62B; Thu, 25 Jun 2026 04:30:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1782387057; bh=qIVB6gHmZfbfjR8XMIsltlHaNah8ksCbKAdOfhqwEPs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fGeVw/tcCrootoIsfVQzEyvJihR1IT/gQKpPyfG2UPZ+f0p9YMIzfqbw+2XT0/O5R Tt48hVLDtCPKYUVM/fRRxpw6BRd4F3rXcYBux3do3SWHc4YwixZR6yH7j3YvnU9M35 bFbNTR4pdD5V3Wp8+6DBI1DZiSbicU9RrdLW0E3Q= From: Dev Jain To: muchun.song@linux.dev, osalvador@suse.de, akpm@linux-foundation.org, ljs@kernel.org, david@kernel.org, liam@infradead.org Cc: Dev Jain , riel@surriel.com, vbabka@kernel.org, harry@kernel.org, jannh@google.com, lance.yang@linux.dev, kas@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, rcampbell@nvidia.com, apopple@nvidia.com, ziy@nvidia.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, gourry@gourry.net, ying.huang@linux.alibaba.com, mel@csn.ul.ie, nao.horiguchi@gmail.com, ak@linux.intel.com, j-nomura@ce.jp.nec.com, pfalcato@suse.de, dave.hansen@intel.com, tglx@kernel.org, jpoimboe@kernel.org, ryan.roberts@arm.com, anshuman.khandual@arm.com Subject: [PATCH 5/5] mm/mprotect: use huge_ptep_get() for hugetlb Date: Thu, 25 Jun 2026 11:29:54 +0000 Message-ID: <20260625112955.3254283-6-dev.jain@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260625112955.3254283-1-dev.jain@arm.com> References: <20260625112955.3254283-1-dev.jain@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit prot_none_hugetlb_entry() is the hugetlb callback for the early mprotect(PROT_NONE) PFN permission walk on x86. The callback passes the decoded PFN to pfn_modify_allowed(). For a hugetlb callback, the pte pointer refers to a hugetlb entry. On architectures where hugetlb entries need huge_ptep_get(), reading that entry with ptep_get() can make the permission check use the wrong PFN. Use huge_ptep_get() before decoding the hugetlb PFN. Currently there is no path which can trigger a bug: huge_ptep_get() is a simple ptep_get() for x86, and the prot_none walk occurs only for x86. But use the correct helper anyways. Fixes: 42e4089c7890 ("x86/speculation/l1tf: Disallow non privileged high MMIO PROT_NONE mappings") Signed-off-by: Dev Jain --- mm/mprotect.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/mm/mprotect.c b/mm/mprotect.c index 9cbf932b028cf..23779632d18bf 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -699,14 +699,20 @@ static int prot_none_pte_entry(pte_t *pte, unsigned long addr, 0 : -EACCES; } +#ifdef CONFIG_HUGETLB_PAGE static int prot_none_hugetlb_entry(pte_t *pte, unsigned long hmask, unsigned long addr, unsigned long next, struct mm_walk *walk) { - return pfn_modify_allowed(pte_pfn(ptep_get(pte)), + pte_t entry = huge_ptep_get(walk->mm, addr, pte); + + return pfn_modify_allowed(pte_pfn(entry), *(pgprot_t *)(walk->private)) ? 0 : -EACCES; } +#else +#define prot_none_hugetlb_entry NULL +#endif static int prot_none_test(unsigned long addr, unsigned long next, struct mm_walk *walk) -- 2.43.0