From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DB2B2FEFB7C for ; Fri, 27 Feb 2026 18:55:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=n6rlrry81JIlRz/zw2nqighk428jPz/tiLfdCGbIMwE=; b=O4XdD6WoXVcXpI950UgjrzJXzd NcG8Qyi7Rp5xCsjfHuhgDj7gazynCsNxpDi1Bd3QWUPuOK8kOxK8/38hmmQDRkAt3jYB2Iad0suFW nzjj92ucLw8eFjVrlGV63CaXX7E5kDpoOxXBQGX3ul5yEmdiN0eyfLetxfivrB+mb3LGZeUyxb+qH jGkzHtkjtC1NnOL774LHEhVlaVlH8GQ74Jc3oQmIiWHZMn5ey2Nbw2mIBZCaUcYmI+rIZFo7oaT/v C+sNTGe1uKUmYwOqzwC6jBKaaAIv8ad71KgFjbgnkM+HyOpuzMTwLeLQ0TlCL0ccqmjJp/trV55Pp rOIRF98w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vw30D-00000008vnW-0rHx; Fri, 27 Feb 2026 18:55:53 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vw309-00000008vnQ-3EaY for linux-arm-kernel@lists.infradead.org; Fri, 27 Feb 2026 18:55:49 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 8FB976012A; Fri, 27 Feb 2026 18:55:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B2ECCC116C6; Fri, 27 Feb 2026 18:55:46 +0000 (UTC) From: Catalin Marinas To: linux-arm-kernel@lists.infradead.org Cc: Anshuman Khandual , Jianpeng Chang , Will Deacon , "Huang, Ying" , Guenter Roeck Subject: [PATCH] arm64: mm: Add PTE_DIRTY back to PAGE_KERNEL* to fix kexec/hibernation Date: Fri, 27 Feb 2026 18:53:06 +0000 Message-ID: <20260227185544.1482632-1-catalin.marinas@arm.com> X-Mailer: git-send-email 2.47.3 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Commit 143937ca51cc ("arm64, mm: avoid always making PTE dirty in pte_mkwrite()") changed pte_mkwrite_novma() to only clear PTE_RDONLY when PTE_DIRTY is set. This was to allow writable-clean PTEs for swap pages that haven't actually been written. However, this broke kexec and hibernation for some platforms. Both go through trans_pgd_create_copy() -> _copy_pte(), which calls pte_mkwrite_novma() to make the temporary linear-map copy fully writable. With the updated pte_mkwrite_novma(), read-only kernel pages (without PTE_DIRTY) remain read-only in the temporary mapping. While such behaviour is fine for user pages where hardware DBM or trapping will make them writeable, subsequent in-kernel writes by the kexec relocation code will fault. Add PTE_DIRTY back to all _PAGE_KERNEL* protection definitions. This was the case prior to 5.4, commit aa57157be69f ("arm64: Ensure VM_WRITE|VM_SHARED ptes are clean by default"). With the kernel linear-map PTEs always having PTE_DIRTY set, pte_mkwrite_novma() correctly clears PTE_RDONLY. Fixes: 143937ca51cc ("arm64, mm: avoid always making PTE dirty in pte_mkwrite()") Signed-off-by: Catalin Marinas Cc: Reported-by: Jianpeng Chang Link: https://lore.kernel.org/r/20251204062722.3367201-1-jianpeng.chang.cn@windriver.com Cc: Will Deacon Cc: "Huang, Ying" Cc: Guenter Roeck --- Since no-one posted this as a proper patch, here it is. However, I could not reproduce the initial kexec failure, so for me kexec is working with our without this patch. Testing appreciated before we decide to merge it. Thanks. arch/arm64/include/asm/pgtable-prot.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h index 2b32639160de..f560e6420267 100644 --- a/arch/arm64/include/asm/pgtable-prot.h +++ b/arch/arm64/include/asm/pgtable-prot.h @@ -50,11 +50,11 @@ #define _PAGE_DEFAULT (_PROT_DEFAULT | PTE_ATTRINDX(MT_NORMAL)) -#define _PAGE_KERNEL (PROT_NORMAL) -#define _PAGE_KERNEL_RO ((PROT_NORMAL & ~PTE_WRITE) | PTE_RDONLY) -#define _PAGE_KERNEL_ROX ((PROT_NORMAL & ~(PTE_WRITE | PTE_PXN)) | PTE_RDONLY) -#define _PAGE_KERNEL_EXEC (PROT_NORMAL & ~PTE_PXN) -#define _PAGE_KERNEL_EXEC_CONT ((PROT_NORMAL & ~PTE_PXN) | PTE_CONT) +#define _PAGE_KERNEL (PROT_NORMAL | PTE_DIRTY) +#define _PAGE_KERNEL_RO ((PROT_NORMAL & ~PTE_WRITE) | PTE_RDONLY | PTE_DIRTY) +#define _PAGE_KERNEL_ROX ((PROT_NORMAL & ~(PTE_WRITE | PTE_PXN)) | PTE_RDONLY | PTE_DIRTY) +#define _PAGE_KERNEL_EXEC ((PROT_NORMAL & ~PTE_PXN) | PTE_DIRTY) +#define _PAGE_KERNEL_EXEC_CONT ((PROT_NORMAL & ~PTE_PXN) | PTE_CONT | PTE_DIRTY) #define _PAGE_SHARED (_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_UXN | PTE_WRITE) #define _PAGE_SHARED_EXEC (_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_WRITE)