From: Sudeep Holla <sudeep.holla@arm.com>
To: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>,
Mark Rutland <Mark.Rutland@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>,
"jcm@redhat.com" <jcm@redhat.com>,
Catalin Marinas <Catalin.Marinas@arm.com>,
"hanjun.guo@linaro.org" <hanjun.guo@linaro.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Olof Johansson <olof@lixom.net>,
"grant.likely@linaro.org" <grant.likely@linaro.org>,
"graeme.gregory@linaro.org" <graeme.gregory@linaro.org>,
Arnd Bergmann <arnd@arndb.de>, Will Deacon <Will.Deacon@arm.com>,
Jason Cooper <jason@lakedaemon.net>,
Marc Zyngier <Marc.Zyngier@arm.com>,
Bjorn Helgaas <bhelgaas@google.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Mark Brown <broonie@kernel.org>, Rob Herring <robh@kernel.org>,
Robert Richter <rric@kernel.org>, Lv Zheng <lv.zheng@intel.com>,
Robert Moore <robert.moore@intel.com>,
Liviu Dudau <Liviu.Dudau@arm.com>,
Randy Dunlap <rdunlap@infradead.org>,
Charles Garcia-Tobin <Charles.Garcia-Tobin@arm.com>,
"linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 02/17] ARM64 / ACPI: Get RSDP and ACPI boot-time tables
Date: Tue, 09 Sep 2014 19:05:09 +0100 [thread overview]
Message-ID: <540F4155.4090200@arm.com> (raw)
In-Reply-To: <20140909175010.GF4948@e102568-lin.cambridge.arm.com>
On 09/09/14 18:50, Lorenzo Pieralisi wrote:
> On Tue, Sep 09, 2014 at 06:15:41PM +0100, Mark Rutland wrote:
>> On Tue, Sep 09, 2014 at 05:41:51PM +0100, Jon Masters wrote:
>>> On 09/09/2014 12:26 PM, Catalin Marinas wrote:
>>>> On Mon, Sep 01, 2014 at 03:57:40PM +0100, Hanjun Guo wrote:
>>>>> diff --git a/arch/arm64/include/asm/acenv.h b/arch/arm64/include/asm/acenv.h
>>>>> new file mode 100644
>>>>> index 0000000..3899ee6
>>>>> --- /dev/null
>>>>> +++ b/arch/arm64/include/asm/acenv.h
>>>>> @@ -0,0 +1,18 @@
>>>>> +/*
>>>>> + * ARM64 specific ACPICA environments and implementation
>>>>> + *
>>>>> + * Copyright (C) 2014, Linaro Ltd.
>>>>> + * Author: Hanjun Guo <hanjun.guo@linaro.org>
>>>>> + * Author: Graeme Gregory <graeme.gregory@linaro.org>
>>>>> + *
>>>>> + * This program is free software; you can redistribute it and/or modify
>>>>> + * it under the terms of the GNU General Public License version 2 as
>>>>> + * published by the Free Software Foundation.
>>>>> + */
>>>>> +
>>>>> +#ifndef _ASM_ACENV_H
>>>>> +#define _ASM_ACENV_H
>>>>> +
>>>>> +#define ACPI_FLUSH_CPU_CACHE() WARN_ONCE(1, "Not currently supported on ARM64")
>>>>
>>>> Does this mean that it will be supported at some point? Looking at the
>>>> places where this function is called, I don't really see how this would
>>>> ever work on ARM. Which means that we add such macro just to be able to
>>>> compile code that would never be used on arm64. I would rather see the
>>>> relevant ACPI files only compiled on x86/IA-64 rather than arm64.
>>>
>>> That specific cache behavior is a part of e.g. ACPI C3 state support
>>> (e.g. ACPI5.1 8.1.4 Processor Power State C3).
>>
>> Per table 5-35, if neither WBINVD or WBINVD_FLUSH are set in the FADT,
>> we don't get S1, S2, or S3 states either.
>>
>>> As you note, it's not going to work on 64-bit ARM as it does on x86,
>>> but it's optional to implement C3 and early 64-bit ARM systems should
>>> not report Wbindv flags in the FADT anyway.
>>
>> Unless the arm cache architecture changes, I wouldn't expect any 64-bit
>> ARM system to set either of the WBINVD flags.
>>
>>> They can also set FADT.P_LVL3_LAT > 1000, which has the effect of
>>> disabling C3 support, while also allowing for use of _CST objects to
>>> define more flexible C-States later on.
>>
>> It sounds like we should be sanity checking these in the arm64 ACPI code
>> for the moment. I don't want us to discover that current platforms
>> report the wrong thing only when new platforms come out that might
>> actually report things correctly.
>
> I think that the kernel must ignore most of the stuff mentioned above
> in HW_REDUCED_ACPI mode. And to be frank I still think that the problem
> is not even there. The problem is trying to compile code that basically
> has no defined behaviour - ie it is unspecified - on ARM64, that's what
> Catalin pointed out.
>
> I understand it is compiled in by default on x86, but that's not a reason
> why we should add empty hooks all over the place to compile code that
> does not stand a chance to be doing anything sensible apart from
> returning an error code, in the best case scenario.
>
I had pointed out this earlier, even if we make it compile there's
every possibility that it can blow up if some vendor adds S- states
to their ACPI tables. One clear reason why it could blow up is:
"
/* This violates the spec but is required for bug compatibility. */
acpi_write_bit_register(ACPI_BITREG_SCI_ENABLE, 1);
"
I don't think this can ever work on ARM platforms. So better to fix it
properly.
Regards,
Sudeep
next prev parent reply other threads:[~2014-09-09 18:05 UTC|newest]
Thread overview: 117+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-01 14:57 [PATCH v3 00/17] Introduce ACPI for ARM64 based on ACPI 5.1 Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 01/17] ARM64: Move the init of cpu_logical_map(0) before unflatten_device_tree() Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 02/17] ARM64 / ACPI: Get RSDP and ACPI boot-time tables Hanjun Guo
2014-09-09 16:26 ` Catalin Marinas
2014-09-09 16:41 ` Jon Masters
2014-09-09 16:44 ` Jon Masters
2014-09-09 17:15 ` Mark Rutland
2014-09-09 17:33 ` Jon Masters
2014-09-09 17:50 ` Lorenzo Pieralisi
2014-09-09 18:05 ` Sudeep Holla [this message]
2014-09-09 19:06 ` Jon Masters
2014-09-10 11:13 ` Hanjun Guo
2014-09-10 12:33 ` Catalin Marinas
2014-09-10 21:51 ` Grant Likely
2014-09-11 11:01 ` Catalin Marinas
2014-09-14 15:40 ` Grant Likely
2014-09-14 21:59 ` Catalin Marinas
2014-09-15 3:53 ` Grant Likely
2014-09-16 5:29 ` Zheng, Lv
2014-09-10 21:41 ` Grant Likely
2014-09-09 16:54 ` Mark Rutland
2014-09-10 7:30 ` Hanjun Guo
2014-09-10 21:37 ` Grant Likely
2014-09-01 14:57 ` [PATCH v3 03/17] ARM64 / ACPI: Introduce lowlevel suspend function Hanjun Guo
2014-09-09 16:35 ` Catalin Marinas
2014-09-09 22:04 ` Graeme Gregory
2014-09-01 14:57 ` [PATCH v3 04/17] ARM64 / ACPI: Introduce early_param for "acpi" Hanjun Guo
2014-09-09 16:37 ` Catalin Marinas
2014-09-09 17:17 ` Bjorn Helgaas
2014-09-09 22:14 ` Jon Masters
2014-09-10 13:04 ` Will Deacon
2014-09-10 13:21 ` Bjorn Helgaas
2014-09-10 18:30 ` Will Deacon
2014-09-10 21:58 ` Grant Likely
2014-09-01 14:57 ` [PATCH v3 05/17] ARM64 / ACPI: If we chose to boot from acpi then disable FDT Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 06/17] ARM64 / ACPI: Make PCI optional for ACPI on ARM64 Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 07/17] ARM64 / ACPI: Parse FADT table to get PSCI flags for PSCI init Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 08/17] ACPI / table: Print GIC information when MADT is parsed Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 09/17] ARM64 / ACPI: Parse MADT for SMP initialization Hanjun Guo
2014-09-03 17:21 ` Lorenzo Pieralisi
2014-09-04 15:29 ` Hanjun Guo
2014-09-09 4:29 ` Jon Masters
2014-09-09 5:11 ` Hanjun Guo
2014-09-09 5:34 ` Jon Masters
2014-09-09 16:52 ` Lorenzo Pieralisi
2014-09-09 17:00 ` Jon Masters
2014-09-09 17:02 ` Jon Masters
2014-09-09 4:23 ` Jon Masters
2014-09-09 4:57 ` Hanjun Guo
2014-09-09 5:44 ` Jon Masters
2014-09-09 16:00 ` Hanjun Guo
2014-09-09 16:04 ` Jon Masters
2014-09-09 16:14 ` Hanjun Guo
2014-09-11 14:15 ` Will Deacon
2014-09-12 21:30 ` Jon Masters
2014-09-11 10:24 ` Grant Likely
2014-09-01 14:57 ` [PATCH v3 10/17] ACPI / processor: Make it possible to get CPU hardware ID via GICC Hanjun Guo
2014-09-03 16:27 ` Lorenzo Pieralisi
2014-09-08 13:10 ` Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 11/17] ARM64 / ACPI: Introduce ACPI_IRQ_MODEL_GIC and register device's gsi Hanjun Guo
2014-09-11 11:08 ` Grant Likely
2014-09-11 11:34 ` Grant Likely
2014-09-12 9:42 ` Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 12/17] ACPI / table: Add new function to get table entries Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 13/17] ARM64 / ACPI: Add GICv2 specific ACPI boot support Hanjun Guo
2014-09-01 17:35 ` Marc Zyngier
2014-09-02 8:28 ` [Linaro-acpi] " Alexander Spyridakis
2014-09-02 11:48 ` Tomasz Nowicki
2014-09-02 13:02 ` Marc Zyngier
2014-09-02 15:45 ` Hanjun Guo
2014-09-02 15:59 ` Marc Zyngier
2014-09-02 16:11 ` Sudeep Holla
2014-09-03 10:30 ` Marc Zyngier
2014-09-03 11:17 ` Hanjun Guo
2014-09-04 14:03 ` Hanjun Guo
2014-09-09 6:21 ` Jon Masters
2014-09-03 9:26 ` Tomasz Nowicki
2014-09-03 14:57 ` Arnd Bergmann
2014-09-05 8:52 ` Tomasz Nowicki
2014-09-05 9:47 ` Marc Zyngier
2014-09-05 10:13 ` [Linaro-acpi] " Arnd Bergmann
2014-09-05 10:36 ` Tomasz Nowicki
2014-09-05 10:39 ` Marc Zyngier
2014-09-05 10:49 ` Tomasz Nowicki
2014-09-09 6:27 ` Jon Masters
2014-09-11 13:43 ` Grant Likely
2014-09-02 16:34 ` Catalin Marinas
2014-09-11 11:48 ` Grant Likely
2014-09-11 12:01 ` Marc Zyngier
2014-09-09 6:14 ` Jon Masters
2014-09-03 18:42 ` Arnd Bergmann
2014-09-04 10:10 ` Tomasz Nowicki
2014-09-04 10:14 ` Arnd Bergmann
2014-09-04 10:39 ` Tomasz Nowicki
2014-09-09 6:35 ` Jon Masters
2014-09-01 14:57 ` [PATCH v3 14/17] ARM64 / ACPI: Parse GTDT to initialize arch timer Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 15/17] ARM64 / ACPI: Select ACPI_REDUCED_HARDWARE_ONLY if ACPI is enabled on ARM64 Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 16/17] ARM64 / ACPI: Enable ARM64 in Kconfig Hanjun Guo
2014-09-11 15:18 ` Lorenzo Pieralisi
2014-09-01 14:57 ` [PATCH v3 17/17] Documentation: ACPI for ARM64 Hanjun Guo
2014-09-11 13:29 ` [PATCH v3 00/17] Introduce ACPI for ARM64 based on ACPI 5.1 Grant Likely
2014-09-11 13:49 ` Will Deacon
2014-09-12 21:38 ` Jon Masters
2014-09-12 21:43 ` Jon Masters
2014-09-15 4:21 ` Grant Likely
2014-09-11 14:23 ` Rafael J. Wysocki
2014-09-11 14:04 ` Grant Likely
2014-09-11 15:37 ` Catalin Marinas
2014-09-11 15:57 ` Sudeep Holla
2014-09-11 16:06 ` Graeme Gregory
2014-09-11 16:14 ` Sudeep Holla
2014-09-15 4:31 ` Grant Likely
2014-09-15 9:15 ` Catalin Marinas
2014-09-15 22:48 ` Grant Likely
2014-09-16 10:12 ` Catalin Marinas
2014-09-11 16:05 ` Olof Johansson
2014-09-15 4:37 ` Grant Likely
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