From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Martin Subject: [PATCH v7 06/27] arm64/sve: Clarify role of the VQ map maintenance functions Date: Fri, 29 Mar 2019 13:00:31 +0000 Message-ID: <1553864452-15080-7-git-send-email-Dave.Martin@arm.com> References: <1553864452-15080-1-git-send-email-Dave.Martin@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 7F4D84A475 for ; Fri, 29 Mar 2019 09:01:55 -0400 (EDT) Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id clqhzzUtNG3s for ; Fri, 29 Mar 2019 09:01:54 -0400 (EDT) Received: from foss.arm.com (foss.arm.com [217.140.101.70]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 12A5E4A41C for ; Fri, 29 Mar 2019 09:01:54 -0400 (EDT) In-Reply-To: <1553864452-15080-1-git-send-email-Dave.Martin@arm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu To: kvmarm@lists.cs.columbia.edu Cc: Okamoto Takayuki , Christoffer Dall , Ard Biesheuvel , Marc Zyngier , Catalin Marinas , Will Deacon , Zhang Lei , Julien Grall , linux-arm-kernel@lists.infradead.org List-Id: kvmarm@lists.cs.columbia.edu 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 Tested-by: zhang.lei --- 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; -- 2.1.4