From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hanjun Guo Subject: Re: [PATCH v5 12/18] ACPI / processor: Make it possible to get CPU hardware ID via GICC Date: Thu, 30 Oct 2014 16:27:36 +0800 Message-ID: <5451F678.5090900@linaro.org> References: <1413553034-20956-1-git-send-email-hanjun.guo@linaro.org> <1413553034-20956-13-git-send-email-hanjun.guo@linaro.org> <20141024173920.GB8303@red-moon> <544E1732.5090902@linaro.org> <20141029104321.GA8896@e102568-lin.cambridge.arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pd0-f171.google.com ([209.85.192.171]:58269 "EHLO mail-pd0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756960AbaJ3I37 (ORCPT ); Thu, 30 Oct 2014 04:29:59 -0400 Received: by mail-pd0-f171.google.com with SMTP id r10so4706495pdi.30 for ; Thu, 30 Oct 2014 01:29:59 -0700 (PDT) In-Reply-To: <20141029104321.GA8896@e102568-lin.cambridge.arm.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Lorenzo Pieralisi Cc: Catalin Marinas , "Rafael J. Wysocki" , Mark Rutland , Olof Johansson , "grant.likely@linaro.org" , Will Deacon , "graeme.gregory@linaro.org" , Arnd Bergmann , Sudeep Holla , "jcm@redhat.com" , Jason Cooper , Marc Zyngier , Bjorn Helgaas , Daniel Lezcano , Mark Brown , Rob Herring , Robert Richter , Lv Zheng , Robert Moore , Liviu Dudau , Randy Dunlap , Charles Garcia-Tobin , Kangkang.Shen@huawei.co On 2014-10-29 18:43, Lorenzo Pieralisi wrote: > On Mon, Oct 27, 2014 at 09:58:10AM +0000, Hanjun Guo wrote: > > [...] > >>>> +static int map_gicc_mpidr(struct acpi_subtable_header *entry, >>>> + int device_declaration, u32 acpi_id, int *mpidr) >>>> +{ >>>> + struct acpi_madt_generic_interrupt *gicc = >>>> + container_of(entry, struct acpi_madt_generic_interrupt, header); >>>> + >>>> + if (!(gicc->flags & ACPI_MADT_ENABLED)) >>>> + return -ENODEV; >>>> + >>>> + /* In the GIC interrupt model, logical processors are >>>> + * required to have a Processor Device object in the DSDT, >>>> + * so we should check device_declaration here >>>> + */ >>>> + if (device_declaration && (gicc->uid == acpi_id)) { >>>> + /* >>>> + * Only bits [0:7] Aff0, bits [8:15] Aff1, bits [16:23] Aff2 >>>> + * and bits [32:39] Aff3 are meaningful, so pack the Affx >>>> + * fields into a single 32 bit identifier to accommodate the >>>> + * acpi processor drivers. >>>> + */ >>>> + *mpidr = ((gicc->arm_mpidr & 0xff00000000) >> 8) >>>> + | gicc->arm_mpidr; >>> >>> The simple fact that you define a function to pack the mpidr value and >>> you can't use it here because this is *generic* code is telling, and >>> a very bad omen. At the cost of sounding like a broken record, I do not >>> like this mpidr->apic->logical_cpu song and dance at all. >>> ACPI is peppered with code (eg hotplug is another example, CPUidle driver >>> even worse) that is supposed to be generic but contains x86 code to carry >>> out this cpuid conversion, I really think that in order to start an ARM64 >>> ACPI port properly we should at least try to factor out this physical to >>> logical cpu id conversion, and it is not the first time that I mention this >>> on the lists. >> >> I know, thanks for pointing this out. As I replied in previous version >> of this patch set, apic_id is x86/ia64 specific, but the meaning behind >> it is not. It means the CPU hardware id to identify itself in the system, >> it just like MPIDR on ARM. > > Yes, except that it is called apic_id. > >> I will send out a patch for RFC to convert apic_id to physid which >> is generic for all platforms. > > That seems a good idea to sound out if I am the only one having an issue > with the current approach. > >>> I will also talk to Rafael about this at the earliest opportunity, I >>> guess that x86 code relies on apic-id because some ACPI versions could >>> not rely on the acpi-id or some other reasons I have to investigate. >> >> As ACPI spec (section 8.4, Declaring Processors) said, Each processor >> in the system must be declared in the ACPI namespace, so each cpu will >> have acpi_id in all ACPI versions, and in theory we can map acpi_id to >> logical cpu id if we want to. >> >> But things are complicated, apic_id is connected to many >> tables, MADT for smp init, DSDT for device driver, and SRAT for NUMA (there >> is no acpi_id in it, ONLY has apic_id in the table for x86/ia64), so if we >> want to factor the code to map acpi_id to logical cpu id, we need to modify: >> >> - ACPI drivers; >> - SMP init for x86 and ia64 >> - the mappings for NUMA init for x86 and ia64 >> that will be lots of work I think. >> >> I'm willing to discuss this further and come out a solution, please >> comment on what I said and share your ideas :) > > Factoring out apic_id to a common cpu_physical_id is ok to me, because > basically that's what you are doing except for the naming. I do not > have any particular preference for the acpi_id, I mentioned that only > as a means to implement a generic cpu_physical_id, arch agnostic. > > Drop the RFC you mentioned above please on the list, we will restart debating > from there. Ok, will send out the patch soon. Thanks Hanjun From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758482AbaJ3IaD (ORCPT ); Thu, 30 Oct 2014 04:30:03 -0400 Received: from mail-pd0-f172.google.com ([209.85.192.172]:43052 "EHLO mail-pd0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751626AbaJ3I37 (ORCPT ); Thu, 30 Oct 2014 04:29:59 -0400 Message-ID: <5451F678.5090900@linaro.org> Date: Thu, 30 Oct 2014 16:27:36 +0800 From: Hanjun Guo User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Lorenzo Pieralisi CC: Catalin Marinas , "Rafael J. Wysocki" , Mark Rutland , Olof Johansson , "grant.likely@linaro.org" , Will Deacon , "graeme.gregory@linaro.org" , Arnd Bergmann , Sudeep Holla , "jcm@redhat.com" , Jason Cooper , Marc Zyngier , Bjorn Helgaas , Daniel Lezcano , Mark Brown , Rob Herring , Robert Richter , Lv Zheng , Robert Moore , Liviu Dudau , Randy Dunlap , Charles Garcia-Tobin , "Kangkang.Shen@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 v5 12/18] ACPI / processor: Make it possible to get CPU hardware ID via GICC References: <1413553034-20956-1-git-send-email-hanjun.guo@linaro.org> <1413553034-20956-13-git-send-email-hanjun.guo@linaro.org> <20141024173920.GB8303@red-moon> <544E1732.5090902@linaro.org> <20141029104321.GA8896@e102568-lin.cambridge.arm.com> In-Reply-To: <20141029104321.GA8896@e102568-lin.cambridge.arm.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2014-10-29 18:43, Lorenzo Pieralisi wrote: > On Mon, Oct 27, 2014 at 09:58:10AM +0000, Hanjun Guo wrote: > > [...] > >>>> +static int map_gicc_mpidr(struct acpi_subtable_header *entry, >>>> + int device_declaration, u32 acpi_id, int *mpidr) >>>> +{ >>>> + struct acpi_madt_generic_interrupt *gicc = >>>> + container_of(entry, struct acpi_madt_generic_interrupt, header); >>>> + >>>> + if (!(gicc->flags & ACPI_MADT_ENABLED)) >>>> + return -ENODEV; >>>> + >>>> + /* In the GIC interrupt model, logical processors are >>>> + * required to have a Processor Device object in the DSDT, >>>> + * so we should check device_declaration here >>>> + */ >>>> + if (device_declaration && (gicc->uid == acpi_id)) { >>>> + /* >>>> + * Only bits [0:7] Aff0, bits [8:15] Aff1, bits [16:23] Aff2 >>>> + * and bits [32:39] Aff3 are meaningful, so pack the Affx >>>> + * fields into a single 32 bit identifier to accommodate the >>>> + * acpi processor drivers. >>>> + */ >>>> + *mpidr = ((gicc->arm_mpidr & 0xff00000000) >> 8) >>>> + | gicc->arm_mpidr; >>> >>> The simple fact that you define a function to pack the mpidr value and >>> you can't use it here because this is *generic* code is telling, and >>> a very bad omen. At the cost of sounding like a broken record, I do not >>> like this mpidr->apic->logical_cpu song and dance at all. >>> ACPI is peppered with code (eg hotplug is another example, CPUidle driver >>> even worse) that is supposed to be generic but contains x86 code to carry >>> out this cpuid conversion, I really think that in order to start an ARM64 >>> ACPI port properly we should at least try to factor out this physical to >>> logical cpu id conversion, and it is not the first time that I mention this >>> on the lists. >> >> I know, thanks for pointing this out. As I replied in previous version >> of this patch set, apic_id is x86/ia64 specific, but the meaning behind >> it is not. It means the CPU hardware id to identify itself in the system, >> it just like MPIDR on ARM. > > Yes, except that it is called apic_id. > >> I will send out a patch for RFC to convert apic_id to physid which >> is generic for all platforms. > > That seems a good idea to sound out if I am the only one having an issue > with the current approach. > >>> I will also talk to Rafael about this at the earliest opportunity, I >>> guess that x86 code relies on apic-id because some ACPI versions could >>> not rely on the acpi-id or some other reasons I have to investigate. >> >> As ACPI spec (section 8.4, Declaring Processors) said, Each processor >> in the system must be declared in the ACPI namespace, so each cpu will >> have acpi_id in all ACPI versions, and in theory we can map acpi_id to >> logical cpu id if we want to. >> >> But things are complicated, apic_id is connected to many >> tables, MADT for smp init, DSDT for device driver, and SRAT for NUMA (there >> is no acpi_id in it, ONLY has apic_id in the table for x86/ia64), so if we >> want to factor the code to map acpi_id to logical cpu id, we need to modify: >> >> - ACPI drivers; >> - SMP init for x86 and ia64 >> - the mappings for NUMA init for x86 and ia64 >> that will be lots of work I think. >> >> I'm willing to discuss this further and come out a solution, please >> comment on what I said and share your ideas :) > > Factoring out apic_id to a common cpu_physical_id is ok to me, because > basically that's what you are doing except for the naming. I do not > have any particular preference for the acpi_id, I mentioned that only > as a means to implement a generic cpu_physical_id, arch agnostic. > > Drop the RFC you mentioned above please on the list, we will restart debating > from there. Ok, will send out the patch soon. Thanks Hanjun From mboxrd@z Thu Jan 1 00:00:00 1970 From: hanjun.guo@linaro.org (Hanjun Guo) Date: Thu, 30 Oct 2014 16:27:36 +0800 Subject: [PATCH v5 12/18] ACPI / processor: Make it possible to get CPU hardware ID via GICC In-Reply-To: <20141029104321.GA8896@e102568-lin.cambridge.arm.com> References: <1413553034-20956-1-git-send-email-hanjun.guo@linaro.org> <1413553034-20956-13-git-send-email-hanjun.guo@linaro.org> <20141024173920.GB8303@red-moon> <544E1732.5090902@linaro.org> <20141029104321.GA8896@e102568-lin.cambridge.arm.com> Message-ID: <5451F678.5090900@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 2014-10-29 18:43, Lorenzo Pieralisi wrote: > On Mon, Oct 27, 2014 at 09:58:10AM +0000, Hanjun Guo wrote: > > [...] > >>>> +static int map_gicc_mpidr(struct acpi_subtable_header *entry, >>>> + int device_declaration, u32 acpi_id, int *mpidr) >>>> +{ >>>> + struct acpi_madt_generic_interrupt *gicc = >>>> + container_of(entry, struct acpi_madt_generic_interrupt, header); >>>> + >>>> + if (!(gicc->flags & ACPI_MADT_ENABLED)) >>>> + return -ENODEV; >>>> + >>>> + /* In the GIC interrupt model, logical processors are >>>> + * required to have a Processor Device object in the DSDT, >>>> + * so we should check device_declaration here >>>> + */ >>>> + if (device_declaration && (gicc->uid == acpi_id)) { >>>> + /* >>>> + * Only bits [0:7] Aff0, bits [8:15] Aff1, bits [16:23] Aff2 >>>> + * and bits [32:39] Aff3 are meaningful, so pack the Affx >>>> + * fields into a single 32 bit identifier to accommodate the >>>> + * acpi processor drivers. >>>> + */ >>>> + *mpidr = ((gicc->arm_mpidr & 0xff00000000) >> 8) >>>> + | gicc->arm_mpidr; >>> >>> The simple fact that you define a function to pack the mpidr value and >>> you can't use it here because this is *generic* code is telling, and >>> a very bad omen. At the cost of sounding like a broken record, I do not >>> like this mpidr->apic->logical_cpu song and dance at all. >>> ACPI is peppered with code (eg hotplug is another example, CPUidle driver >>> even worse) that is supposed to be generic but contains x86 code to carry >>> out this cpuid conversion, I really think that in order to start an ARM64 >>> ACPI port properly we should at least try to factor out this physical to >>> logical cpu id conversion, and it is not the first time that I mention this >>> on the lists. >> >> I know, thanks for pointing this out. As I replied in previous version >> of this patch set, apic_id is x86/ia64 specific, but the meaning behind >> it is not. It means the CPU hardware id to identify itself in the system, >> it just like MPIDR on ARM. > > Yes, except that it is called apic_id. > >> I will send out a patch for RFC to convert apic_id to physid which >> is generic for all platforms. > > That seems a good idea to sound out if I am the only one having an issue > with the current approach. > >>> I will also talk to Rafael about this at the earliest opportunity, I >>> guess that x86 code relies on apic-id because some ACPI versions could >>> not rely on the acpi-id or some other reasons I have to investigate. >> >> As ACPI spec (section 8.4, Declaring Processors) said, Each processor >> in the system must be declared in the ACPI namespace, so each cpu will >> have acpi_id in all ACPI versions, and in theory we can map acpi_id to >> logical cpu id if we want to. >> >> But things are complicated, apic_id is connected to many >> tables, MADT for smp init, DSDT for device driver, and SRAT for NUMA (there >> is no acpi_id in it, ONLY has apic_id in the table for x86/ia64), so if we >> want to factor the code to map acpi_id to logical cpu id, we need to modify: >> >> - ACPI drivers; >> - SMP init for x86 and ia64 >> - the mappings for NUMA init for x86 and ia64 >> that will be lots of work I think. >> >> I'm willing to discuss this further and come out a solution, please >> comment on what I said and share your ideas :) > > Factoring out apic_id to a common cpu_physical_id is ok to me, because > basically that's what you are doing except for the naming. I do not > have any particular preference for the acpi_id, I mentioned that only > as a means to implement a generic cpu_physical_id, arch agnostic. > > Drop the RFC you mentioned above please on the list, we will restart debating > from there. Ok, will send out the patch soon. Thanks Hanjun