From patchwork Tue Mar 19 17:51:57 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Martin X-Patchwork-Id: 10860131 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id F1D8A14DE for ; Tue, 19 Mar 2019 17:54:22 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CCE962870E for ; Tue, 19 Mar 2019 17:54:22 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BE471287A6; Tue, 19 Mar 2019 17:54:22 +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=-5.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED 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 5B0F12870E for ; Tue, 19 Mar 2019 17:54:22 +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:References: In-Reply-To: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:List-Owner; bh=9lZiw+pfBzeZ+P7XcHIqJyLW2Fc3SkYQH1wpVGFLbzk=; b=AyPzzeK6NgSCgNLdEdpyT75WU8 l7Idd/k60Wy1pG1LmDCHL/mBy/nffNH5QBW6CM5Rq/r/ruakgDmaWc7yAsL8Lgy2wpXgWmjwWmEFi IambbpLJLZBFRfM021eXH44Xq4Cz0hvlH0C3MI1V7dBuZzXps8kJ0pbRgnCfa7XlVz205dU9F8Vyw mnlrNdxLM4zD/MLCR8SWt2kQ6+MituR1+28TsuKOuJ01REhDshJOJgnsmUPRD7Mg/F4VjjH5ijKSW /oQdfSJgAvJ8IbTBUiSAUdnOikfUK0L6yX4+KmhU7yfdsR5MgqLRSnBxaloT1UGxZP6rn83Qt4D0g O0FDCe9Q==; 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 1h6IwI-00022l-IB; Tue, 19 Mar 2019 17:54:14 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h6IvO-0000wZ-TQ for linux-arm-kernel@lists.infradead.org; Tue, 19 Mar 2019 17:53:20 +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 5B55E174E; Tue, 19 Mar 2019 10:53:18 -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 6B5AD3F614; Tue, 19 Mar 2019 10:53:16 -0700 (PDT) From: Dave Martin To: kvmarm@lists.cs.columbia.edu Subject: [PATCH v6 06/27] arm64/sve: Clarify role of the VQ map maintenance functions Date: Tue, 19 Mar 2019 17:51:57 +0000 Message-Id: <1553017938-710-7-git-send-email-Dave.Martin@arm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1553017938-710-1-git-send-email-Dave.Martin@arm.com> References: <1553017938-710-1-git-send-email-Dave.Martin@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190319_105319_032194_3F1D765B X-CRM114-Status: GOOD ( 14.61 ) 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: Peter Maydell , Okamoto Takayuki , Christoffer Dall , Ard Biesheuvel , Marc Zyngier , Catalin Marinas , Will Deacon , Zhang Lei , Julien Grall , =?utf-8?q?Alex_Benn=C3=A9e?= , linux-arm-kernel@lists.infradead.org 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 The roles of sve_init_vq_map(), sve_update_vq_map() and sve_verify_vq_map() are highly non-obvious to anyone who has not dug through cpufeatures.c in detail. Since the way these functions interact with each other is more important here than a full understanding of the cpufeatures code, this patch adds comments to make the functions' roles clearer. No functional change. Signed-off-by: Dave Martin Reviewed-by: Julien Thierry Reviewed-by: Julien Grall --- Changes since v5: * [Julien Thierry] This patch is useful for explaining the previous patch (as per the v5 ordering), and is anyway non-functional. Swapped it with the previous patch to provide a more logical reading order for the series. --- arch/arm64/kernel/fpsimd.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 62c37f0..f59ea67 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -647,6 +647,10 @@ static void sve_probe_vqs(DECLARE_BITMAP(map, SVE_VQ_MAX)) } } +/* + * Initialise the set of known supported VQs for the boot CPU. + * This is called during kernel boot, before secondary CPUs are brought up. + */ void __init sve_init_vq_map(void) { sve_probe_vqs(sve_vq_map); @@ -655,6 +659,7 @@ void __init sve_init_vq_map(void) /* * If we haven't committed to the set of supported VQs yet, filter out * those not supported by the current CPU. + * This function is called during the bring-up of early secondary CPUs only. */ void sve_update_vq_map(void) { @@ -662,7 +667,10 @@ void sve_update_vq_map(void) bitmap_and(sve_vq_map, sve_vq_map, sve_secondary_vq_map, SVE_VQ_MAX); } -/* Check whether the current CPU supports all VQs in the committed set */ +/* + * Check whether the current CPU supports all VQs in the committed set. + * This function is called during the bring-up of late secondary CPUs only. + */ int sve_verify_vq_map(void) { int ret = 0;