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[192.237.175.120]) by mx.google.com with ESMTPS id e1si11560922qta.71.2016.05.23.07.19.09 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 23 May 2016 07:19:09 -0700 (PDT) Received-SPF: neutral (google.com: 192.237.175.120 is neither permitted nor denied by best guess record for domain of xen-devel-bounces@lists.xen.org) client-ip=192.237.175.120; Authentication-Results: mx.google.com; spf=neutral (google.com: 192.237.175.120 is neither permitted nor denied by best guess record for domain of xen-devel-bounces@lists.xen.org) smtp.mailfrom=xen-devel-bounces@lists.xen.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1b4qgE-0003hu-17; Mon, 23 May 2016 14:18:02 +0000 Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1b4qgD-0003fx-4i for xen-devel@lists.xen.org; Mon, 23 May 2016 14:18:01 +0000 Received: from [85.158.139.211] by server-9.bemta-5.messagelabs.com id 1E/E7-12567-81113475; Mon, 23 May 2016 14:18:00 +0000 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrBLMWRWlGSWpSXmKPExsVysyfVTVdc0Dn c4MNebYslHxezODB6HN39mymAMYo1My8pvyKBNePp/DlsBb/FKy7f/MDSwDhTuIuRi0NIYCOj xKT1i9khnNOMEq/3nmHqYuTkYBPQlLjz+ROYLSIgLXHt82VGkCJmgTmMEmse/GUGSQgLeEpc6 XnGBmKzCKhKtC+4ywpi8wq4StzYsZwdxJYQkJM4eWwyWJwTKL79yzlGEFtIwEWi49ZO9gmM3A sYGVYxahSnFpWlFukamuolFWWmZ5TkJmbm6BoamOrlphYXJ6an5iQmFesl5+duYgT6mAEIdjA 2bPc8xCjJwaQkyntyh1O4EF9SfkplRmJxRnxRaU5q8SFGGQ4OJQnezfzO4UKCRanpqRVpmTnA YINJS3DwKInwHuIDSvMWFyTmFmemQ6ROMSpKifNOA+kTAElklObBtcEC/BKjrJQwLyPQIUI8B alFuZklqPKvGMU5GJWEebeATOHJzCuBm/4KaDET0OKH0g4gi0sSEVJSDYyLr6rbMxazXVsv/T B1adAnhmq9SKHQ447HvUKv2zHZGjyaOWexIOPL/6XFpeLxMnd+ydnc+hfuUFF7/7CW1q8NZR4 L2A6t+fPCtnPH97QyjdqAm//mrxez+M5ykyvfbbGDtXvQ/gutrvF1Ap9yene9Oae727V98/6w 1Qy+zCYM3A/s9nK+S1NiKc5INNRiLipOBAAAsVT/awIAAA== X-Env-Sender: julien.grall@arm.com X-Msg-Ref: server-3.tower-206.messagelabs.com!1464013068!37465424!8 X-Originating-IP: [217.140.101.70] X-SpamReason: No, hits=0.0 required=7.0 tests= X-StarScan-Received: X-StarScan-Version: 8.34; banners=-,-,- X-VirusChecked: Checked Received: (qmail 35344 invoked from network); 23 May 2016 14:17:59 -0000 Received: from foss.arm.com (HELO foss.arm.com) (217.140.101.70) by server-3.tower-206.messagelabs.com with SMTP; 23 May 2016 14:17:59 -0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3089D59; Mon, 23 May 2016 07:18:21 -0700 (PDT) Received: from e108454-lin.cambridge.arm.com (e108454-lin.cambridge.arm.com [10.1.215.28]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id DEDFA3F21A; Mon, 23 May 2016 07:17:57 -0700 (PDT) From: Julien Grall To: xen-devel@lists.xen.org Date: Mon, 23 May 2016 15:17:28 +0100 Message-Id: <1464013052-32587-12-git-send-email-julien.grall@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1464013052-32587-1-git-send-email-julien.grall@arm.com> References: <1464013052-32587-1-git-send-email-julien.grall@arm.com> Cc: sstabellini@kernel.org, wei.liu2@citrix.com, steve.capper@arm.com, andre.przywara@arm.com, Julien Grall , wei.chen@linaro.org Subject: [Xen-devel] [PATCH v2 11/15] xen/arm: Document the errata implemented in Xen X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" The new document will help to keep track of all the erratum that Xen is able to handle. The text is based on the Linux doc in Documents/arm64/silicon-errata.txt. Also list the current errata that Xen is aware of. Signed-off-by: Julien Grall --- docs/misc/arm/silicon-errata.txt | 45 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 docs/misc/arm/silicon-errata.txt diff --git a/docs/misc/arm/silicon-errata.txt b/docs/misc/arm/silicon-errata.txt new file mode 100644 index 0000000..3f0d32b --- /dev/null +++ b/docs/misc/arm/silicon-errata.txt @@ -0,0 +1,45 @@ + Silicon Errata and Software Workarounds + ======================================= + +It is an unfortunate fact of life that hardware is often produced with +so-called "errata", which can cause it to deviate from the architecture +under specific circumstances. For hardware produced by ARM, these +errata are broadly classified into the following categories: + + Category A: A critical error without a viable workaround. + Category B: A significant or critical error with an acceptable + workaround. + Category C: A minor error that is not expected to occur under normal + operation. + +For more information, consult one of the "Software Developers Errata +Notice" documents available on infocenter.arm.com (registration +required). + +As far as Xen is concerned, Category B errata may require some special +treatment in the hypervisor. For example, avoiding a particular sequence +of code, or configuring the processor in a particular way. A less common +situation may require similar actions in order to declassify a Category A +erratum into a Category C erratum. These are collectively known as +"software workarounds" and are only required in the minority of cases +(e.g. those cases that both require a non-secure workaround *and* can +be triggered by Linux). + +For software workarounds that may adversely impact systems unaffected by +the erratum in question, a Kconfig entry is added under "ARM errata +workarounds via the alternatives framework". These are enabled by default +and patched in at runtime when an affected CPU is detected. For +less-intrusive workarounds, a Kconfig option is not available and the code +is structured (preferably with a comment) in such a way that the erratum +will not be hit. + +This approach can make it slightly onerous to determine exactly which +errata are worked around in an arbitrary hypervisor source tree, so this +file acts as a registry of software workarounds in the Xen hypervisor and +will be updated when new workarounds are committed and backported to +stable hypervisors. + +| Implementor | Component | Erratum ID | Kconfig | ++----------------+-----------------+-----------------+-------------------------+ +| ARM | Cortex-A15 | #766422 | N/A | +| ARM | Cortex-A57 | #852523 | N/A |