From patchwork Fri Mar 23 18:08:31 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Martin X-Patchwork-Id: 10305271 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 09B9360386 for ; Fri, 23 Mar 2018 18:08:55 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E51C928E28 for ; Fri, 23 Mar 2018 18:08:54 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D97F128F4D; Fri, 23 Mar 2018 18:08:54 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 2151B28EE1 for ; Fri, 23 Mar 2018 18:08:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Message-Id:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To: References:List-Owner; bh=INt+9Lh1+EmXfYjSRCsFZnxRhBg1FDik9umtaitW+zQ=; b=aIc VUFD9DY04ryab0B2ZlyzAOLq9DXC9Ra7koy/qf8JUGFBnCIAO/S7GO9KnDB2U8EVnuTnFKV3NEXSY KnGqWiM3StYxJlPC3x3BrRHtI8Ucw78WLDthvYycBmuQR23u1RGWnG1DFH3HPNxXFdbYKiQLz7BOa xfhrsIxFOTOjo8CRdYzO9CMuD6qYdl2+nHLQFvyLmMVKiVi/JeQVCot75Tv9KCda9gAx3i9g2dNks T6mXga/uncMThPuTHl8qSC5XwyY8XDB4kwCfxZYMMoynwZV+BmVlwpSZ58BazDLeG1dymNjUJmzTh r7iRY0GlSRLzX0UwIKm2mNZuU4CqSSA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1ezR7S-0000zM-ML; Fri, 23 Mar 2018 18:08:50 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1ezR7Q-0000xn-3A for linux-arm-kernel@lists.infradead.org; Fri, 23 Mar 2018 18:08:49 +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 72C881529; Fri, 23 Mar 2018 11:08:36 -0700 (PDT) Received: from e103592.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 40F8B3F487; Fri, 23 Mar 2018 11:08:35 -0700 (PDT) From: Dave Martin To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v2] arm64/sve: Document firmware support requirements in Kconfig Date: Fri, 23 Mar 2018 18:08:31 +0000 Message-Id: <1521828511-30946-1-git-send-email-Dave.Martin@arm.com> X-Mailer: git-send-email 2.1.4 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180323_110848_151631_D36F05BF X-CRM114-Status: GOOD ( 13.42 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Dan Handley , Mark Rutland , Suzuki K Poulose , Will Deacon , Catalin Marinas MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP Use of SVE by EL2 and below requires explicit support in the firmware. There is no means to hide the presence of SVE from EL2, so a kernel configured with CONFIG_ARM64_SVE=y will typically not work correctly on SVE capable hardware unless the firmware does include the appropriate support. This is not expected to pose a problem in the wild, since platform integrators are responsible for ensuring that they ship up-to-date firmware to support their hardware. However, developers may hit the issue when using mismatched compoments. In order to draw attention to the issue and how to solve it, this patch adds some Kconfig text giving a brief explanation and details of compatible firmware versions. Signed-off-by: Dave Martin Acked-by: Catalin Marinas --- Changes since v1: * Fixed a typo ("firware") reported by Suzuki --- arch/arm64/Kconfig | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 7381eeb..4fc7057 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1104,6 +1104,23 @@ config ARM64_SVE To enable use of this extension on CPUs that implement it, say Y. + Note that for architectural reasons, firmware _must_ implement SVE + support when running on SVE capable hardware. The required support + is present in: + + * version 1.5 and later of the ARM Trusted Firmware + * the AArch64 boot wrapper since commit 5e1261e08abf + ("bootwrapper: SVE: Enable SVE for EL2 and below"). + + For other firmware implementations, consult the firmware documentation + or vendor. + + If you need the kernel to boot on SVE-capable hardware with broken + firmware, you may need to say N here until you get your firmware + fixed. Otherwise, you may experience firmware panics or lockups when + booting the kernel. If unsure and you are not observing these + symptoms, you should assume that it is safe to say Y. + config ARM64_MODULE_CMODEL_LARGE bool