From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753486AbbCZXBY (ORCPT ); Thu, 26 Mar 2015 19:01:24 -0400 Received: from mail-pd0-f172.google.com ([209.85.192.172]:34031 "EHLO mail-pd0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753333AbbCZXBW (ORCPT ); Thu, 26 Mar 2015 19:01:22 -0400 Message-ID: <55148FB6.1030106@linaro.org> Date: Fri, 27 Mar 2015 07:01:10 +0800 From: Hanjun Guo User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: Will Deacon CC: Catalin Marinas , "Rafael J. Wysocki" , Olof Johansson , "grant.likely@linaro.org" , Mark Rutland , Ashwin Chaugule , Lorenzo Pieralisi , Robert Richter , Arnd Bergmann , "graeme.gregory@linaro.org" , "linaro-acpi@lists.linaro.org" , Marc Zyngier , "jcm@redhat.com" , Timur Tabi , "msalter@redhat.com" , "linux-kernel@vger.kernel.org" , Tomasz Nowicki , "linux-acpi@vger.kernel.org" , Mark Brown , "suravee.suthikulpanit@amd.com" , Sudeep Holla , "linux-arm-kernel@lists.infradead.org" Subject: Re: [patch v11 12/23] ARM64 / ACPI: Parse MADT for SMP initialization References: <1427205776-5060-1-git-send-email-hanjun.guo@linaro.org> <1427205776-5060-13-git-send-email-hanjun.guo@linaro.org> <20150325171735.GI14585@localhost> <20150326151510.GI2805@arm.com> <551462A2.4070308@linaro.org> <20150326211239.GA23660@arm.com> In-Reply-To: <20150326211239.GA23660@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015年03月27日 05:12, Will Deacon wrote: > On Thu, Mar 26, 2015 at 07:48:50PM +0000, Hanjun Guo wrote: >> On 2015年03月26日 23:15, Will Deacon wrote: >>> commit 8ef320319592693f4a6286d80df210fd47b3e356 >>> Author: Will Deacon >>> Date: Thu Mar 26 15:09:20 2015 +0000 >>> >>> ARM64 / ACPI: fix usage of acpi_map_gic_cpu_interface >>> >>> acpi_parse_gic_cpu_interface calls acpi_map_gic_cpu_interface by both >>> passing a 32-bit value in the u8 enabled parameter and then subsequently >>> ignoring its return value. >>> >>> Sort it out. >>> >>> Reported-by: Catalin Marinas >>> Signed-off-by: Will Deacon >>> >>> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c >>> index cd60329da8c4..07649e413244 100644 >>> --- a/arch/arm64/kernel/acpi.c >>> +++ b/arch/arm64/kernel/acpi.c >>> @@ -103,9 +103,12 @@ void __init __acpi_unmap_table(char *map, unsigned long size) >>> * >>> * Returns the logical cpu number which maps to MPIDR >>> */ >>> -static int __init acpi_map_gic_cpu_interface(u64 mpidr, u8 enabled) >>> +static int __init >>> +acpi_map_gic_cpu_interface(struct acpi_madt_generic_interrupt *processor) >> >> How about just replace u8 with u32? This function has its purpose to >> be lived, on x86/ia64, ACPI core will get the physcal cpu ID via >> ACPI handle, then pass it to the arch specific mapping function >> to map the physcal cpu ID with logical cpu ID for the new added >> CPU, so when ACPI based CPU hot-plug is introduced on ARM64, we >> need to go back to that solution. > > If/when that happens, we can change things then. Right now, this is a static > function with one caller. One step at a time, please. > >>> { >>> int i; >>> + u64 mpidr = processor->arm_mpidr & MPIDR_HWID_BITMASK; >>> + bool enabled = !!(processor->flags & ACPI_MADT_ENABLED); >>> >>> if (mpidr == INVALID_HWID) { >>> pr_info("Skip MADT cpu entry with invalid MPIDR\n"); >>> @@ -178,11 +181,7 @@ acpi_parse_gic_cpu_interface(struct acpi_subtable_header *header, >>> return -EINVAL; >>> >>> acpi_table_print_madt_entry(header); >>> - >>> - acpi_map_gic_cpu_interface(processor->arm_mpidr & MPIDR_HWID_BITMASK, >>> - processor->flags & ACPI_MADT_ENABLED); >>> - >>> - return 0; >>> + return acpi_map_gic_cpu_interface(processor); >> >> I don't think we need to return the error value here, in ACPI >> core, it will stop the MADT scanning once it returned the error >> value, but actually we can skip some disabled GICC (cpu) entries >> and find all the enabled ones in MADT, for example, >> >> cpu0 entry, with flag enabled >> cpu1 entry, disabled - if we return the error value, table scanning >> will stop >> cpu2 entry, enabled - and this cpu will be ignored > > Then send me a patch making acpi_map_gic_cpu_interface have a void return > type. Ignoring the return type is usually a good way to introduce subtle > bugs. OK, I will, and I will cleanup the comments for this function too. Need some sleep first... Thanks Hanjun