Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753287AbcDVKc7 (ORCPT ); Fri, 22 Apr 2016 06:32:59 -0400 Received: from foss.arm.com ([217.140.101.70]:60867 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753050AbcDVKc4 (ORCPT ); Fri, 22 Apr 2016 06:32:56 -0400 Date: Fri, 22 Apr 2016 11:32:50 +0100 From: Mark Rutland To: Stefano Stabellini , catalin.marinas@arm.com, will.deacon@arm.com Cc: linux-arm-kernel@lists.infradead.org, julien.grall@arm.com, david.vrabel@citrix.com, xen-devel@lists.xen.org, devicetree@vger.kernel.org, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, shannon.zhao@linaro.org, peter.huangpeng@huawei.com Subject: Re: [PATCH v11 12/17] ARM64: ACPI: Check if it runs on Xen to enable or disable ACPI Message-ID: <20160422103250.GC10606@leverpostej> References: <1460030614-16112-1-git-send-email-zhaoshenglong@huawei.com> <1460030614-16112-13-git-send-email-zhaoshenglong@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3061 Lines: 103 On Wed, Apr 20, 2016 at 10:34:41AM +0100, Stefano Stabellini wrote: > Hello Mark, > > do you think that this patch addresses your previous comments > (http://marc.info/?l=devicetree&m=145926913008544&w=2) appropriately? > > Thanks, > > Stefano > > On Thu, 7 Apr 2016, Shannon Zhao wrote: > > From: Shannon Zhao > > > > When it's a Xen domain0 booting with ACPI, it will supply a /chosen and > > a /hypervisor node in DT. So check if it needs to enable ACPI. > > > > Signed-off-by: Shannon Zhao > > Reviewed-by: Stefano Stabellini > > Acked-by: Hanjun Guo > > --- > > arch/arm64/kernel/acpi.c | 14 ++++++++++---- > > 1 file changed, 10 insertions(+), 4 deletions(-) > > > > diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c > > index d1ce8e2..57ee317 100644 > > --- a/arch/arm64/kernel/acpi.c > > +++ b/arch/arm64/kernel/acpi.c > > @@ -67,10 +67,15 @@ static int __init dt_scan_depth1_nodes(unsigned long node, > > { > > /* > > * Return 1 as soon as we encounter a node at depth 1 that is > > - * not the /chosen node. > > + * not the /chosen node, or /hypervisor node with compatible > > + * string "xen,xen". > > */ > > - if (depth == 1 && (strcmp(uname, "chosen") != 0)) > > - return 1; > > + if (depth == 1 && (strcmp(uname, "chosen") != 0)) { > > + if (strcmp(uname, "hypervisor") != 0 || > > + !of_flat_dt_is_compatible(node, "xen,xen")) > > + return 1; > > + } > > + > > return 0; > > } Is the duplicate node checking logic I mentioned in that review gone? i.e. do we not need an is_xen_node() helper? Additionally, IMO, this would be easier to follow without the nested conditionals, e.g. static int __init dt_scan_depth1_nodes(unsigned long node, const char *uname, int depth, void *data) { /* * Ignore anything not directly under the root node; we'll * catch its parent instead. */ if (depth != 1) return 0; if (strcmp(uname, "chosen") == 0) return 0; if (strcmp(uname, "hypervisor") == 0 && of_flat_dt_is_compatible(node, "xen,xen")) return 0; /* * This node at depth 1 is neither a chosen node nor a xen node, * which we do not expect. */ return 1; } Otherwise, this looks fine to me. FWIW, either way: Acked-by: Mark Rutland As this is core arm64 code, I believe you'll need acks from Catalin and/or Will (and likewise for patch 15), unless I've missed those. Thanks, Mark. > > > > @@ -184,7 +189,8 @@ void __init acpi_boot_table_init(void) > > /* > > * Enable ACPI instead of device tree unless > > * - ACPI has been disabled explicitly (acpi=off), or > > - * - the device tree is not empty (it has more than just a /chosen node) > > + * - the device tree is not empty (it has more than just a /chosen node, > > + * and a /hypervisor node when running on Xen) > > * and ACPI has not been force enabled (acpi=force) > > */ > > if (param_acpi_off || > > -- > > 2.0.4 > > > > >