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 438DF481FC8 for ; Tue, 5 May 2026 16:07:41 +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=1777997262; cv=none; b=P5sB6kLm9eaWABsBQMf/UAzew7gIvYIioLJHQmfRhNTxCCIvr719MBilp5FA2hH6cwHW46S6dH/++Vfk3gxxZOfjp0nwAif4526ZYCJ/ZoElMpp2PFV2c75g0BNOY+DIsjiLKn8wqCMrnLX/bbcbEsvA+SEoQVpy3M/d2Cfviys= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777997262; c=relaxed/simple; bh=g5SIlfhNFVkGHqg4H9aglJHNTgTJdaH8G/qaojIJDnE=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=ETjml8tew4yGon7xPk/quhEFcRcHc+3wrlxQk8QhxFLsCBoprndE/Jda37PFxlwDKmKLsdRFDtNuf8VTC7/s40C0iGyEhuy20VtWhUq/JtoaPKxrF0QXWpdSYBvYBNVFWTNjG9WiiPvI31Cw4hXYPikYKqv4bM3QROwTQLjaaxQ= 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=KkYtO8mZ; 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="KkYtO8mZ" 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 3F23014BF; Tue, 5 May 2026 09:07:35 -0700 (PDT) Received: from localhost.localdomain (e123572-lin.cambridge.arm.com [10.1.194.54]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 76B503F763; Tue, 5 May 2026 09:07:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1777997260; bh=g5SIlfhNFVkGHqg4H9aglJHNTgTJdaH8G/qaojIJDnE=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=KkYtO8mZqdaw92smrCGaZTzZI/VIzEyKkmaReuGHOucgR+tC88xl9fofAudD6UVpk k8mMgNRteA9j5G51xbINy6Vsrn2R/ZjvzJ3WLH6+D35W1zPhu88N6Lht8mUvcMEWUs dFkjBvRkKGt4/X16YT0hU7+djWqlw+f9qAt5Hw2s= From: Kevin Brodsky Date: Tue, 05 May 2026 17:05:57 +0100 Subject: [PATCH RFC v7 08/24] arm64: Initialize POR_EL1 register on cpu_resume() Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260505-kpkeys-v7-8-20c0bdd97197@arm.com> References: <20260505-kpkeys-v7-0-20c0bdd97197@arm.com> In-Reply-To: <20260505-kpkeys-v7-0-20c0bdd97197@arm.com> To: linux-hardening@vger.kernel.org Cc: Kevin Brodsky , Andrew Morton , Andy Lutomirski , Catalin Marinas , Dave Hansen , "David Hildenbrand (Arm)" , Ira Weiny , Jann Horn , Jeff Xu , Joey Gouly , Kees Cook , Linus Walleij , Marc Zyngier , Mark Brown , Matthew Wilcox , Maxwell Bland , "Mike Rapoport (IBM)" , Peter Zijlstra , Pierre Langlois , Quentin Perret , Rick Edgecombe , Ryan Roberts , Will Deacon , Yang Shi , Yeoreum Yun , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, x86@kernel.org, Lorenzo Stoakes , Thomas Gleixner , Vlastimil Babka X-Mailer: b4 0.15.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1777997220; l=1238; i=kevin.brodsky@arm.com; s=20260427; h=from:subject:message-id; bh=X72DCdJX2SxlqX4hafcg68D9WxF9xj/CvQA2EQYYzDc=; b=fim2j4aK2yghbZYMjdBQCOZyKY91r9Ul0SwmGZQdrKUeEhqyNGE1v6WJFGHlbNiKl5XqoqcSj w/Gou1BnYSkAXgMZuyZl+N93zHfpv3GYcZkYHunaDhY0KWNQFbc8UfN X-Developer-Key: i=kevin.brodsky@arm.com; a=ed25519; pk=N2QG+eJKrvkNovwhhwJhnJ4+ScVfsGCHldmqLfcMTFs= From: Yeoreum Yun The POR_EL1 register is reset to an unknown value after cpu_suspend(). Since POR_EL1 always holds POR_EL1_INIT when entering cpu_suspend(), initialize POR_EL1 with POR_EL1_INIT before cpu_do_resume(). Signed-off-by: Yeoreum Yun Signed-off-by: Kevin Brodsky --- arch/arm64/kernel/sleep.S | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S index f093cdf71be1..e0a6ad85cd24 100644 --- a/arch/arm64/kernel/sleep.S +++ b/arch/arm64/kernel/sleep.S @@ -3,6 +3,7 @@ #include #include #include +#include #include .text @@ -134,6 +135,17 @@ SYM_FUNC_START(_cpu_resume) /* load sp from context */ ldr x2, [x0, #CPU_CTX_SP] mov sp, x2 + +#ifdef CONFIG_ARM64_POE +alternative_if_not ARM64_HAS_S1POE + b .Lskip_por_set +alternative_else_nop_endif + mov_q x2, POR_EL1_INIT + msr_s SYS_POR_EL1, x2 + /* isb can be skipped since cpu_do_resume() will do it. */ +.Lskip_por_set: +#endif /* CONFIG_ARM64_POE */ + /* * cpu_do_resume expects x0 to contain context address pointer */ -- 2.51.2