From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E3FE5606A323 for ; Thu, 12 Nov 2026 13:16:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=WiCUQhQA; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=qhR8siKF 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: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Unsubscribe-Post: List-Owner; bh=wTBvg55fBuWD5tQeyFYmzV7yA87nWgeKUd2BDomzFCs=; b=WiCUQhQAHrktwr 6XTz82m6I5UBwHNfpSbzWXm/roy+NEvtgc4lGc2PrQ8I5nfUfP0y0PhnZQ6ccqFIINrsEvLXEtn7G zfbp6HeWCNIaz+YZxsgmZ5qeblDr1G612PGs42glLdEOMkKBK8xIjkfo0RLen6rMDEBnoBa/mYzm8 odOacVA6orU+xn5toDin1MlmFHUHQGKPvFcEbmzdnPeggjV3ktB28jfqgnYGMtrRFr7bh3Dl8/fvc PukwElDZXGbo31bZ2TtEATJ2pxc9JsGeg0ZlG2KnRjiC8K3b+Dd+LgovWeadKv3hGbNUCpJgLJxz9 RWZFdttseNaKdBIKrsBA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xRUfW-00000009ztQ-3w3f; Thu, 12 Nov 2026 13:16:46 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xRUfU-00000009zt8-06Yc for linux-arm-kernel@lists.infradead.org; Thu, 12 Nov 2026 13:16:45 +0000 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 25CFD1477; Thu, 12 Nov 2026 05:16:40 -0800 (PST) Received: from [10.57.59.183] (unknown [10.57.59.183]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 008353F632; Thu, 12 Nov 2026 05:16:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1794489403; bh=wTBvg55fBuWD5tQeyFYmzV7yA87nWgeKUd2BDomzFCs=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=qhR8siKF3uHjUA/hWmh1H8py+Ns7uPCZYEMtvUSIeYR5dIH30FjHUDT4bD49VvDcb I5k/ohiMpYz3LO+MsI+K1M42BEms0asveRWV7ANV92sDMfAMZoQct9bN5pPyWH2lLi +OTp7Uve9C+YFkm6cp8nZIyyLv2wUgeasDHv3a7E= Message-ID: <9148043e-580c-42e5-a93f-3a177f8d75df@arm.com> Date: Thu, 12 Nov 2026 14:16:33 +0100 X-Archived-By: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC v10 07/22] arm64: Initialize POR_EL1 register on cpu_resume() To: Mark Brown Cc: Yeoreum Yun , linux-hardening@vger.kernel.org, Andrew Morton , Ard Biesheuvel , Andy Lutomirski , Catalin Marinas , Dave Hansen , "David Hildenbrand (Arm)" , Jann Horn , Jeff Xu , Joey Gouly , Kees Cook , Linu Cherian , Linus Walleij , Marc Zyngier , Matthew Wilcox , Maxwell Bland , "Mike Rapoport (IBM)" , Peter Zijlstra , Pierre Langlois , =?UTF-8?Q?Pierre-Cl=C3=A9ment_Tosi?= , Quentin Perret , Rick Edgecombe , Ryan Roberts , Vlastimil Babka , Will Deacon , Yang Shi , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, x86@kernel.org, Ira Weiny , Lorenzo Stoakes , Thomas Gleixner References: <20261109-kpkeys-v10-0-aa6c4d9603bc@arm.com> <20261109-kpkeys-v10-7-aa6c4d9603bc@arm.com> <7b92f7c8-1543-447e-8ef3-aba608141699@arm.com> <6808f3a6-1c12-4cb2-a109-30704d812490@sirena.org.uk> From: Kevin Brodsky Content-Language: en-GB In-Reply-To: <6808f3a6-1c12-4cb2-a109-30704d812490@sirena.org.uk> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261112_051644_134834_CA0F4F99 X-CRM114-Status: UNSURE ( 8.36 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -4.4 (----) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-7.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On 12/11/2026 14:02, Mark Brown wrote: >> Agreed (as Sashiko reported as well). Presumably that means we also need >> an ISB after writing to POR_EL1 in cpu_enable_poe(), as that's basically >> the same situation. > Possibly just have one before writing TCR2_EL1 rather than for each of > the indvididual features, that's harder to mess up? cpu_enable_poe() directly writes to TCR2_EL1 so surely the extra ISB has to be there (between writing to POR_EL1 and writing to TCR2_EL1)? In _cpu_resume for now I'd keep the ISB directly after writing to POR_EL1, as I'm not sure the ordering is needed for anything but POE and it seems easier to follow with the ISB right after POR_EL1. - Kevin