From: grant.likely@linaro.org (Grant Likely)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 02/17] ARM64 / ACPI: Get RSDP and ACPI boot-time tables
Date: Wed, 10 Sep 2014 22:41:15 +0100 [thread overview]
Message-ID: <20140910214115.BFF3DC40FE6@trevor.secretlab.ca> (raw)
In-Reply-To: <5410326F.8080104@huawei.com>
On Wed, 10 Sep 2014 19:13:51 +0800, Hanjun Guo <guohanjun@huawei.com> wrote:
> On 2014/9/10 3:06, Jon Masters wrote:
> > On 09/09/2014 02:05 PM, Sudeep Holla wrote:
> >>
> >>
> >> 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.
> >
> > Hanjun,
> >
> > How do you want to proceed? I'm not sure it should be !HW_REDUCED_MODE
> > for the cache behavior, because an embedded x86 box would still probably
> > define those, but removing the hooks on ARM may make sense.
>
> As Graeme said in the reply, for sleep we are doing the same thing as
> ia64 in stubbing out the functions, and before that we are trying to remove
> the hooks on ARM by introducing more stubs and making things more complicated.
>
> I agree that we should rework the ACPI core to make sleep/cache related
> stuff compatible with ARM, but I think we may not do this in one go, it will
> need incremental changes over the next couple of years as real hardware
> starts to appear and we finalise the standards to support this.
Yes, reworking acpica is out of scope for this patch set. I don't think
it makes sense to try and do that refactoring here.
g.
next prev parent reply other threads:[~2014-09-10 21:41 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
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 [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20140910214115.BFF3DC40FE6@trevor.secretlab.ca \
--to=grant.likely@linaro.org \
--cc=linux-arm-kernel@lists.infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).