Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755024AbbBDJsV (ORCPT ); Wed, 4 Feb 2015 04:48:21 -0500 Received: from mail-pa0-f44.google.com ([209.85.220.44]:62693 "EHLO mail-pa0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753826AbbBDJsP (ORCPT ); Wed, 4 Feb 2015 04:48:15 -0500 Message-ID: <54D1EAD5.4080105@linaro.org> Date: Wed, 04 Feb 2015 17:48:05 +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: Catalin Marinas , Mark Rutland CC: "Rafael J. Wysocki" , Olof Johansson , Arnd Bergmann , "grant.likely@linaro.org" , Will Deacon , Lorenzo Pieralisi , "graeme.gregory@linaro.org" , Sudeep Holla , "jcm@redhat.com" , Jason Cooper , Marc Zyngier , Bjorn Helgaas , Daniel Lezcano , Mark Brown , Rob Herring , Robert Richter , Randy Dunlap , Charles Garcia-Tobin , "phoenix.liyi@huawei.com" , Timur Tabi , Ashwin Chaugule , "suravee.suthikulpanit@amd.com" , Mark Langsdorf , "wangyijing@huawei.com" , "linux-acpi@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linaro-acpi@lists.linaro.org" Subject: Re: [PATCH v8 14/21] ACPI / processor: Make it possible to get CPU hardware ID via GICC References: <1422881149-8177-1-git-send-email-hanjun.guo@linaro.org> <1422881149-8177-15-git-send-email-hanjun.guo@linaro.org> <20150203141749.GA32536@leverpostej> <20150203200936.GA21731@e104818-lin.cambridge.arm.com> In-Reply-To: <20150203200936.GA21731@e104818-lin.cambridge.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 Content-Length: 3487 Lines: 91 On 2015年02月04日 04:09, Catalin Marinas wrote: > On Tue, Feb 03, 2015 at 02:17:49PM +0000, Mark Rutland wrote: >> On Mon, Feb 02, 2015 at 12:45:42PM +0000, Hanjun Guo wrote: >>> Introduce a new function map_gicc_mpidr() to allow MPIDRs to be obtained >>> from the GICC Structure introduced by ACPI 5.1. >>> >>> MPIDR is the CPU hardware ID as local APIC ID on x86 platform, so we use >>> MPIDR not the GIC CPU interface ID to identify CPUs. >>> >>> Further steps would typedef a phys_id_t for in arch code(with >>> appropriate size and a corresponding invalid value, say ~0) and use that >>> instead of an int in drivers/acpi/processor_core.c to store phys_id, then >>> no need for mpidr packing. >> >> I don't understand why we don't fix this now, and I'm very worried that >> this patch leaves much potential for FW bugs due to potential Linux >> bugs. >> >> Having a function called cpu_physical_id which _does not_ return a >> physical ID makes no sense to me. Any time we really need a physical >> ID, we're still going to have to unpack it (in an architecture-specific >> manner). > > Do you mean something like this? Only briefly tested on Juno and I may > have missed other calls: Thanks, I think it is Mark's suggestion (and also Lorenzo's) > > diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h > index ea4d2b35c57b..4fafd62b1b86 100644 > --- a/arch/arm64/include/asm/acpi.h > +++ b/arch/arm64/include/asm/acpi.h > @@ -49,33 +49,12 @@ static inline void enable_acpi(void) > acpi_noirq = 0; > } > > -/* MPIDR value provided in GICC structure is 64 bits, but the > - * existing phys_id (CPU hardware ID) using in acpi processor > - * driver is 32-bit, to conform to the same datatype we need > - * to repack the GICC structure MPIDR. > - * > - * bits other than following 32 bits are defined as 0, so it > - * will be no information lost after repacked. > - * > - * Bits [0:7] Aff0; > - * Bits [8:15] Aff1; > - * Bits [16:23] Aff2; > - * Bits [32:39] Aff3; > - */ > -static inline u32 pack_mpidr(u64 mpidr) > -{ > - return (u32) ((mpidr & 0xff00000000) >> 8) | mpidr; > -} > - > /* > * The ACPI processor driver for ACPI core code needs this macro > * to find out this cpu was already mapped (mapping from CPU hardware > * ID to CPU logical ID) or not. > - * > - * cpu_logical_map(cpu) is the mapping of MPIDR and the logical cpu, > - * and MPIDR is the cpu hardware ID we needed to pack. > */ > -#define cpu_physical_id(cpu) pack_mpidr(cpu_logical_map(cpu)) > +#define cpu_physical_id(cpu) cpu_logical_map(cpu) > > /* > * It's used from ACPI core in kdump to boot UP system with SMP kernel, > diff --git a/arch/arm64/include/asm/smp_plat.h b/arch/arm64/include/asm/smp_plat.h > index 59e282311b58..a492276e008d 100644 > --- a/arch/arm64/include/asm/smp_plat.h > +++ b/arch/arm64/include/asm/smp_plat.h > @@ -40,4 +40,6 @@ static inline u32 mpidr_hash_size(void) > extern u64 __cpu_logical_map[NR_CPUS]; > #define cpu_logical_map(cpu) __cpu_logical_map[cpu] > > +typedef u64 cpuid_t; I think cpuid_t is a little confused because people may recognize it as cpu logical id, its original meaning is the physical cpu ID, so how about: typedef u64 phys_id_t; ? Thanks Hanjun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/