From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: linux-pm@vger.kernel.org, loongarch@lists.linux.dev,
linux-acpi@vger.kernel.org, linux-arch@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-riscv@lists.infradead.org, kvmarm@lists.linux.dev,
x86@kernel.org, acpica-devel@lists.linuxfoundation.org,
linux-csky@vger.kernel.org, linux-doc@vger.kernel.org,
linux-ia64@vger.kernel.org, linux-parisc@vger.kernel.org,
Salil Mehta <salil.mehta@huawei.com>,
Jean-Philippe Brucker <jean-philippe@linaro.org>,
jianyong.wu@arm.com, justin.he@arm.com,
James Morse <james.morse@arm.com>
Subject: Re: [PATCH RFC v3 01/21] ACPI: Only enumerate enabled (or functional) devices
Date: Thu, 14 Dec 2023 17:55:14 +0000 [thread overview]
Message-ID: <ZXtBgtB8FXs8ge0h@shell.armlinux.org.uk> (raw)
In-Reply-To: <20231214173241.0000260f@Huawei.com>
On Thu, Dec 14, 2023 at 05:32:41PM +0000, Jonathan Cameron wrote:
> On Wed, 13 Dec 2023 12:49:16 +0000
> Russell King (Oracle) <rmk+kernel@armlinux.org.uk> wrote:
>
> > From: James Morse <james.morse@arm.com>
> >
> > Today the ACPI enumeration code 'visits' all devices that are present.
> >
> > This is a problem for arm64, where CPUs are always present, but not
> > always enabled. When a device-check occurs because the firmware-policy
> > has changed and a CPU is now enabled, the following error occurs:
> > | acpi ACPI0007:48: Enumeration failure
> >
> > This is ultimately because acpi_dev_ready_for_enumeration() returns
> > true for a device that is not enabled. The ACPI Processor driver
> > will not register such CPUs as they are not 'decoding their resources'.
> >
> > Change acpi_dev_ready_for_enumeration() to also check the enabled bit.
> > ACPI allows a device to be functional instead of maintaining the
> > present and enabled bit. Make this behaviour an explicit check with
> > a reference to the spec, and then check the present and enabled bits.
> > This is needed to avoid enumerating present && functional devices that
> > are not enabled.
> >
> > Signed-off-by: James Morse <james.morse@arm.com>
> > Tested-by: Miguel Luis <miguel.luis@oracle.com>
> > Tested-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
> > Tested-by: Jianyong Wu <jianyong.wu@arm.com>
> > Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
> > ---
> > If this change causes problems on deployed hardware, I suggest an
> > arch opt-in: ACPI_IGNORE_STA_ENABLED, that causes
> > acpi_dev_ready_for_enumeration() to only check the present bit.
>
> My gut feeling (having made ACPI 'fixes' in the past that ran into
> horribly broken firmware and had to be reverted) is reduce the blast
> radius preemptively from the start. I'd love to live in a world were
> that wasn't necessary but I don't trust all the generators of ACPI tables.
> I'll leave it to Rafael and other ACPI experts suggest how narrow we should
> make it though - arch opt in might be narrow enough.
Yes, I think an arch opt-in would be the most sensible way forward, if
Rafael concurs with that idea. I notice that what I wrote there was
actually an opt-out. I'll fix that.
> > + /*
> > + * ACPI 6.5's 6.3.7 "_STA (Device Status)" allows firmware to return
> > + * (!present && functional) for certain types of devices that should be
> > + * enumerated. Note that the enabled bit can't be sert until the present
>
> set until
Thanks for spotting that, fixed.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!
next prev parent reply other threads:[~2023-12-14 17:55 UTC|newest]
Thread overview: 121+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-13 12:47 [RFC PATCH v3 00/21] ACPI/arm64: add support for virtual cpu hotplug Russell King (Oracle)
2023-12-13 12:49 ` [PATCH RFC v3 01/21] ACPI: Only enumerate enabled (or functional) devices Russell King
2023-12-14 17:32 ` Jonathan Cameron
2023-12-14 17:47 ` Rafael J. Wysocki
2023-12-14 18:10 ` Russell King (Oracle)
2023-12-14 18:16 ` Rafael J. Wysocki
2023-12-14 18:37 ` Rafael J. Wysocki
2023-12-15 15:31 ` Russell King (Oracle)
2023-12-15 16:15 ` Jonathan Cameron
2023-12-15 19:47 ` Rafael J. Wysocki
2024-01-02 14:39 ` Jonathan Cameron
2024-01-11 10:19 ` Jonathan Cameron
2024-01-11 10:26 ` Russell King (Oracle)
2024-01-12 11:52 ` Jonathan Cameron
2024-01-29 14:55 ` Russell King (Oracle)
2024-01-29 15:05 ` Rafael J. Wysocki
2024-01-29 15:16 ` Russell King (Oracle)
2024-01-29 15:34 ` Rafael J. Wysocki
2024-01-22 7:31 ` Gavin Shan
2023-12-14 17:55 ` Russell King (Oracle) [this message]
2023-12-13 12:49 ` [PATCH RFC v3 02/21] ACPI: processor: Add support for processors described as container packages Russell King
2023-12-14 17:36 ` Jonathan Cameron
2023-12-14 17:57 ` Russell King (Oracle)
2023-12-18 20:17 ` Rafael J. Wysocki
2024-01-09 15:49 ` Russell King (Oracle)
2024-01-09 16:05 ` Rafael J. Wysocki
2024-01-09 16:13 ` Russell King (Oracle)
2024-01-11 16:17 ` Jonathan Cameron
2024-01-11 17:59 ` Jonathan Cameron
2024-01-11 18:46 ` Russell King (Oracle)
2024-01-12 9:25 ` Jonathan Cameron
2024-01-12 15:01 ` Rafael J. Wysocki
2024-01-12 15:03 ` Jonathan Cameron
2024-01-15 10:47 ` Russell King (Oracle)
2023-12-13 12:49 ` [PATCH RFC v3 03/21] ACPI: processor: Register CPUs that are online, but not described in the DSDT Russell King
2023-12-18 20:22 ` Rafael J. Wysocki
2024-01-15 11:06 ` Russell King (Oracle)
2024-01-22 16:02 ` Jonathan Cameron
2024-01-22 16:22 ` Rafael J. Wysocki
2024-01-22 17:30 ` Russell King (Oracle)
2024-01-23 9:27 ` Jonathan Cameron
2024-01-25 13:56 ` Miguel Luis
2024-01-25 14:42 ` Rafael J. Wysocki
2024-01-29 13:03 ` Jonathan Cameron
2024-01-29 15:32 ` Russell King (Oracle)
2024-01-22 17:27 ` Russell King (Oracle)
2023-12-13 12:49 ` [PATCH RFC v3 04/21] ACPI: processor: Register all CPUs from acpi_processor_get_info() Russell King
2023-12-14 17:38 ` Jonathan Cameron
2023-12-18 20:30 ` Rafael J. Wysocki
2024-01-22 17:44 ` Jonathan Cameron
2024-01-22 18:03 ` Rafael J. Wysocki
2024-01-22 21:56 ` Russell King (Oracle)
2023-12-13 12:49 ` [PATCH RFC v3 05/21] ACPI: Rename ACPI_HOTPLUG_CPU to include 'present' Russell King
2023-12-14 17:41 ` Jonathan Cameron
2023-12-14 18:00 ` Russell King (Oracle)
2023-12-18 20:35 ` Rafael J. Wysocki
2024-01-22 18:00 ` Jonathan Cameron
2024-01-23 13:28 ` Russell King (Oracle)
2024-01-23 16:15 ` Rafael J. Wysocki
2024-01-23 16:36 ` Russell King (Oracle)
2024-01-23 17:43 ` Rafael J. Wysocki
2024-01-23 18:19 ` Russell King (Oracle)
2024-01-23 18:26 ` Rafael J. Wysocki
2024-01-23 18:59 ` Russell King (Oracle)
2024-01-23 19:27 ` Rafael J. Wysocki
2024-01-23 20:09 ` Russell King (Oracle)
2024-01-23 20:17 ` Rafael J. Wysocki
2024-01-23 20:57 ` Russell King (Oracle)
2024-01-23 21:12 ` Russell King (Oracle)
2024-01-23 22:05 ` Rafael J. Wysocki
2024-01-24 8:45 ` Russell King (Oracle)
2023-12-13 12:49 ` [PATCH RFC v3 06/21] ACPI: Move acpi_bus_trim_one() before acpi_scan_hot_remove() Russell King
2023-12-13 12:49 ` [PATCH RFC v3 07/21] ACPI: Rename acpi_processor_hotadd_init and remove pre-processor guards Russell King
2023-12-14 17:43 ` Jonathan Cameron
2023-12-14 18:03 ` Russell King (Oracle)
2023-12-13 12:49 ` [PATCH RFC v3 08/21] ACPI: Add post_eject to struct acpi_scan_handler for cpu hotplug Russell King
2023-12-13 12:49 ` [PATCH RFC v3 09/21] ACPI: convert acpi_processor_post_eject() to use IS_ENABLED() Russell King (Oracle)
2023-12-15 16:11 ` Jonathan Cameron
2023-12-13 12:50 ` [PATCH RFC v3 10/21] ACPI: Check _STA present bit before making CPUs not present Russell King
2023-12-15 16:18 ` Jonathan Cameron
2023-12-13 12:50 ` [PATCH RFC v3 11/21] ACPI: Warn when the present bit changes but the feature is not enabled Russell King
2023-12-13 12:50 ` [PATCH RFC v3 12/21] arm64: acpi: Move get_cpu_for_acpi_id() to a header Russell King
2023-12-13 12:50 ` [PATCH RFC v3 13/21] ACPICA: Add new MADT GICC flags fields Russell King
2023-12-15 16:23 ` Jonathan Cameron
2023-12-15 16:53 ` Russell King (Oracle)
2023-12-18 9:23 ` Lorenzo Pieralisi
2023-12-18 13:14 ` Rafael J. Wysocki
2023-12-18 16:28 ` Lorenzo Pieralisi
2023-12-27 11:15 ` Lorenzo Pieralisi
2023-12-13 12:50 ` [PATCH RFC v3 14/21] irqchip/gic-v3: Don't return errors from gic_acpi_match_gicc() Russell King
2023-12-15 16:33 ` Jonathan Cameron
2024-01-09 19:27 ` Russell King (Oracle)
2024-01-23 10:08 ` Jonathan Cameron
2023-12-13 12:50 ` [PATCH RFC v3 15/21] irqchip/gic-v3: Add support for ACPI's disabled but 'online capable' CPUs Russell King
2023-12-15 16:38 ` Jonathan Cameron
2023-12-13 12:50 ` [PATCH RFC v3 16/21] arm64: psci: Ignore DENIED CPUs Russell King
2023-12-15 16:40 ` Jonathan Cameron
2023-12-13 12:50 ` [PATCH RFC v3 17/21] ACPI: add support to register CPUs based on the _STA enabled bit Russell King
2023-12-18 13:03 ` Russell King (Oracle)
2024-01-02 14:53 ` Jonathan Cameron
2024-01-23 10:26 ` Jonathan Cameron
2024-01-23 13:10 ` Russell King (Oracle)
2024-01-23 14:22 ` Jonathan Cameron
2024-01-23 14:59 ` Russell King (Oracle)
2023-12-13 12:50 ` [PATCH RFC v3 18/21] ACPI: processor: Only call arch_unregister_cpu() if HOTPLUG_CPU is selected Russell King
2023-12-15 16:50 ` Jonathan Cameron
2023-12-18 12:58 ` Russell King (Oracle)
2024-01-23 10:29 ` Jonathan Cameron
2023-12-13 12:50 ` [PATCH RFC v3 19/21] arm64: document virtual CPU hotplug's expectations Russell King
2023-12-15 17:04 ` Jonathan Cameron
2023-12-13 12:50 ` [PATCH RFC v3 20/21] ACPI: Add _OSC bits to advertise OS support for toggling CPU present/enabled Russell King
2023-12-15 17:12 ` Jonathan Cameron
2024-01-02 13:07 ` Jose Marinho
2024-01-02 15:16 ` Jonathan Cameron
2024-01-02 15:35 ` Jose Marinho
2024-01-23 10:51 ` Jonathan Cameron
2023-12-13 12:50 ` [PATCH RFC v3 21/21] cpumask: Add enabled cpumask for present CPUs that can be brought online Russell King
2023-12-15 17:18 ` Jonathan Cameron
2023-12-18 12:14 ` Russell King (Oracle)
2024-01-02 15:19 ` Jonathan Cameron
2023-12-15 19:40 ` Thomas Gleixner
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