| Age | Commit message (Collapse) | Author |
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The 'offline' file in sysfs shows all offline CPUs, including those
that aren't present. User-space is expected to remove not-present CPUs
from this list to learn which CPUs could be brought online.
CPUs can be present but not-enabled. These CPUs can't be brought online
until the firmware policy changes, which comes with an ACPI notification
that will register the CPUs.
With only the offline and present files, user-space is unable to
determine which CPUs it can try to bring online. Add a new CPU mask
that shows this based on all the registered CPUs.
Signed-off-by: James Morse <james.morse@arm.com>
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Platform firmware can disabled a CPU, or make it not-present by making
an eject-request notification, then waiting for the os to make it offline
and call _EJx. After the firmware updates _STA with the new status.
Not all operating systems support this. For arm64 making CPUs not-present
has never been supported. For all ACPI architectures, making CPUs disabled
has recently been added. Firmware can't know what the OS has support for.
Add two new _OSC bits to advertise whether the OS supports the _STA enabled
or present bits being toggled for CPUs. This will be important for arm64
if systems that support physical CPU hotplug ever appear as arm64 linux
doesn't currently support this, so firmware shouldn't try.
Advertising this support to firmware is useful for cloud orchestrators
to know whether they can scale a particular VM by adding CPUs.
Signed-off-by: James Morse <james.morse@arm.com>
---
I'm assuming Loongarch machines do not support physical CPU hotplug.
Changes since RFC v3:
* Drop ia64 changes
* Update James' comment below "---" to remove reference to ia64
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Add a description of physical and virtual CPU hotplug, explain the
differences and elaborate on what is required in ACPI for a working
virtual hotplug system.
Signed-off-by: James Morse <james.morse@arm.com>
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The kbuild robot points out that configurations without HOTPLUG_CPU
selected can try to build acpi_processor_post_eject() without success
as arch_unregister_cpu() is not defined.
Check this explicitly. This will be merged into:
| ACPI: Add post_eject to struct acpi_scan_handler for cpu hotplug
for any subsequent posting.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: James Morse <james.morse@arm.com>
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acpi_processor_get_info() registers all present CPUs. Registering a
CPU is what creates the sysfs entries and triggers the udev
notifications.
arm64 virtual machines that support 'virtual cpu hotplug' use the
enabled bit to indicate whether the CPU can be brought online, as
the existing ACPI tables require all hardware to be described and
present.
If firmware describes a CPU as present, but disabled, skip the
registration. Such CPUs are present, but can't be brought online for
whatever reason. (e.g. firmware/hypervisor policy).
Once firmware sets the enabled bit, the CPU can be registered and
brought online by user-space. Online CPUs, or CPUs that are missing
an _STA method must always be registered.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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When a CPU is marked as disabled, but online capable in the MADT, PSCI
applies some firmware policy to control when it can be brought online.
PSCI returns DENIED to a CPU_ON request if this is not currently
permitted. The OS can learn the current policy from the _STA enabled bit.
Handle the PSCI DENIED return code gracefully instead of printing an
error.
See https://developer.arm.com/documentation/den0022/f/?lang=en page 58.
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
[ morse: Rewrote commit message ]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
Changes since RFC v2
* Add specification reference
* Use EPERM rather than EPROBE_DEFER
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To support virtual CPU hotplug, ACPI has added an 'online capable' bit
to the MADT GICC entries. This indicates a disabled CPU entry may not
be possible to online via PSCI until firmware has set enabled bit in
_STA.
What about the redistributor in the GICC entry? ACPI doesn't want to say.
Assume the worst: When a redistributor is described in the GICC entry,
but the entry is marked as disabled at boot, assume the redistributor
is inaccessible.
The GICv3 driver doesn't support late online of redistributors, so this
means the corresponding CPU can't be brought online either. Clear the
possible and present bits.
Systems that want CPU hotplug in a VM can ensure their redistributors
are always-on, and describe them that way with a GICR entry in the MADT.
When mapping redistributors found via GICC entries, handle the case
where the arch code believes the CPU is present and possible, but it
does not have an accessible redistributor. Print a warning and clear
the present and possible bits.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
----
Disabled but online-capable CPUs cause this message to be printed
if their redistributors are described via GICC:
| GICv3: CPU 3's redistributor is inaccessible: this CPU can't be brought online
If ACPI's _STA tries to make the cpu present later, this message is printed:
| Changing CPU present bit is not supported
Changes since RFC v2:
* use gicc->flags & (ACPI_MADT_ENABLED | ACPI_MADT_GICC_CPU_CAPABLE)
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gic_acpi_match_gicc() is only called via gic_acpi_count_gicr_regions().
It should only count the number of enabled redistributors, but it
also tries to sanity check the GICC entry, currently returning an
error if the Enabled bit is set, but the gicr_base_address is zero.
Adding support for the online-capable bit to the sanity check
complicates it, for no benefit. The existing check implicitly
depends on gic_acpi_count_gicr_regions() previous failing to find
any GICR regions (as it is valid to have gicr_base_address of zero if
the redistributors are described via a GICR entry).
Instead of complicating the check, remove it. Failures that happen
at this point cause the irqchip not to register, meaning no irqs
can be requested. The kernel grinds to a panic() pretty quickly.
Without the check, MADT tables that exhibit this problem are still
caught by gic_populate_rdist(), which helpfully also prints what
went wrong:
| CPU4: mpidr 100 has no re-distributor!
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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Add the new flag field to the MADT's GICC structure.
'Online Capable' indicates a disabled CPU can be enabled later. See
ACPI specification 6.5 Tabel 5.37: GICC CPU Interface Flags.
Signed-off-by: James Morse <james.morse@arm.com>
---
This patch probably needs to go via the upstream acpica project,
but is included here so the feature can be tested.
If the ACPICA header files are updated before merging this patch set,
this patch will need to be dropped.
Changes since RFC v2:
* Add ACPI specification reference.
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ACPI identifies CPUs by UID. get_cpu_for_acpi_id() maps the ACPI UID
to the linux CPU number.
The helper to retrieve this mapping is only available in arm64's numa
code.
Move it to live next to get_acpi_id_for_cpu().
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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ACPI firmware can trigger the events to add and remove CPUs, but the
OS may not support this.
Print an error message when this happens.
This gives early warning on arm64 systems that don't support
CONFIG_ACPI_HOTPLUG_PRESENT_CPU, as making CPUs not present has
side effects for other parts of the system.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
Changes since RFC v2:
* Update commit message with suggestion from Gavin Shan
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When called acpi_processor_post_eject() unconditionally make a CPU
not-present and unregisters it.
To add support for AML events where the CPU has become disabled, but
remains present, the _STA method should be checked before calling
acpi_processor_remove().
Rename acpi_processor_post_eject() acpi_processor_remove_possible(), and
check the _STA before calling.
Adding the function prototype for arch_unregister_cpu() allows the
preprocessor guards to be removed.
After this change CPUs will remain registered and visible to
user-space as offline if buggy firmware triggers an eject-request,
but doesn't clear the corresponding _STA bits after _EJ0 has been
called.
Signed-off-by: James Morse <james.morse@arm.com>
---
Changes since RFC v3:
* Move IS_ENABLED(CONFIG_ACPI_HOTPLUG_PRESENT_CPU) into separate patch.
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Rather than ifdef'ing acpi_processor_post_eject() and its use site, use
IS_ENABLED() to increase compile coverage.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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struct acpi_scan_handler has a detach callback that is used to remove
a driver when a bus is changed. When interacting with an eject-request,
the detach callback is called before _EJ0.
This means the ACPI processor driver can't use _STA to determine if a
CPU has been made not-present, or some of the other _STA bits have been
changed. acpi_processor_remove() needs to know the value of _STA after
_EJ0 has been called.
Add a post_eject callback to struct acpi_scan_handler. This is called
after acpi_scan_hot_remove() has successfully called _EJ0. Because
acpi_bus_trim_one() also clears the handler pointer, it needs to be
told if the caller will go on to call acpi_bus_post_eject(), so
that acpi_device_clear_enumerated() and clearing the handler pointer
can be deferred. The existing not-used pointer is used for this.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Joanthan Cameron <Jonathan.Cameron@huawei.com>
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acpi_processor_hotadd_init() will make a CPU present by mapping it
based on its hardware id.
'hotadd_init' is ambiguous once there are two different behaviours
for cpu hotplug. This is for toggling the _STA present bit. Subsequent
patches will add support for toggling the _STA enabled bit, named
acpi_processor_make_enabled().
Rename it acpi_processor_make_present() to make it clear this is
for CPUs that were not previously present.
Expose the function prototypes it uses to allow the preprocessor
guards to be removed. The IS_ENABLED() check will let the compiler
dead-code elimination pass remove this if it isn't going to be
used.
Signed-off-by: James Morse <james.morse@arm.com>
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A subsequent patch will change acpi_scan_hot_remove() to call
acpi_bus_trim_one() instead of acpi_bus_trim(), meaning it can no longer
rely on the prototype in the header file.
Move these functions further up the file.
No change in behaviour.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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The code behind ACPI_HOTPLUG_CPU allows a not-present CPU to become
present. This isn't the only use of HOTPLUG_CPU. On arm64 and riscv
CPUs can be taken offline as a power saving measure.
On arm64 an offline CPU may be disabled by firmware, preventing it from
being brought back online, but it remains present throughout.
Adding code to prevent user-space trying to online these disabled CPUs
needs some additional terminology.
Rename the Kconfig symbol CONFIG_ACPI_HOTPLUG_PRESENT_CPU to reflect
that it makes possible CPUs present.
HOTPLUG_CPU is untouched as this is only about the ACPI mechanism.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
Changes since RFC v2:
* Add Loongarch update
Changes since RFC v3:
* Dropped ia64 changes
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To allow ACPI to skip the call to arch_register_cpu() when the _STA
value indicates the CPU can't be brought online right now, move the
arch_register_cpu() call into acpi_processor_get_info().
Systems can still be booted with 'acpi=off', or not include an
ACPI description at all. For these, the CPUs continue to be
registered by cpu_dev_register_generic().
This moves the CPU register logic back to a subsys_initcall(),
while the memory nodes will have been registered earlier.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
Changes since RFC v2:
* Fixup comment in acpi_processor_get_info() (Gavin Shan)
* Add comment in cpu_dev_register_generic() (Gavin Shan)
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ACPI has two descriptions of CPUs, one in the MADT/APIC table, the other
in the DSDT. Both are required. (ACPI 6.5's 8.4 "Declaring Processors"
says "Each processor in the system must be declared in the ACPI
namespace"). Having two descriptions allows firmware authors to get
this wrong.
If CPUs are described in the MADT/APIC, they will be brought online
early during boot. Once the register_cpu() calls are moved to ACPI,
they will be based on the DSDT description of the CPUs. When CPUs are
missing from the DSDT description, they will end up online, but not
registered.
Add a helper that runs after acpi_init() has completed to register
CPUs that are online, but weren't found in the DSDT. Any CPU that
is registered by this code triggers a firmware-bug warning and kernel
taint.
Qemu TCG only describes the first CPU in the DSDT, unless cpu-hotplug
is configured.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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ACPI has two ways of describing processors in the DSDT. From ACPI v6.5,
5.2.12:
"Starting with ACPI Specification 6.3, the use of the Processor() object
was deprecated. Only legacy systems should continue with this usage. On
the Itanium architecture only, a _UID is provided for the Processor()
that is a string object. This usage of _UID is also deprecated since it
can preclude an OSPM from being able to match a processor to a
non-enumerable device, such as those defined in the MADT. From ACPI
Specification 6.3 onward, all processor objects for all architectures
except Itanium must now use Device() objects with an _HID of ACPI0007,
and use only integer _UID values."
Also see https://uefi.org/specs/ACPI/6.5/08_Processor_Configuration_and_Control.html#declaring-processors
Duplicate descriptions are not allowed, the ACPI processor driver already
parses the UID from both devices and containers. acpi_processor_get_info()
returns an error if the UID exists twice in the DSDT.
The missing probe for CPUs described as packages creates a problem for
moving the cpu_register() calls into the acpi_processor driver, as CPUs
described like this don't get registered, leading to errors from other
subsystems when they try to add new sysfs entries to the CPU node.
(e.g. topology_sysfs_init()'s use of topology_add_dev() via cpuhp)
To fix this, parse the processor container and call acpi_processor_add()
for each processor that is discovered like this. The processor container
handler is added with acpi_scan_add_handler(), so no detach call will
arrive.
Qemu TCG describes CPUs using processor devices in a processor container.
For more information, see build_cpus_aml() in Qemu hw/acpi/cpu.c and
https://uefi.org/specs/ACPI/6.5/08_Processor_Configuration_and_Control.html#processor-container-device
Signed-off-by: James Morse <james.morse@arm.com>
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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>
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.
Changes since RFC v2:
* Incorporate comment suggestion by Gavin Shan.
Other review comments from Jonathan Cameron not yet addressed.
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Convert riscv to use the arch_cpu_is_hotpluggable() helper rather than
arch_register_cpu().
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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Now that GENERIC_CPU_DEVICES calls arch_register_cpu(), which can be
overridden by the arch code, switch over to this to allow common code
to choose when the register_cpu() call is made.
This allows topology_init() to be removed.
This is an intermediate step to the logic being moved to drivers/acpi,
where GENERIC_CPU_DEVICES will do the work when booting with acpi=off.
This patch also has the effect of moving the registration of CPUs from
subsys to driver core initialisation, prior to any initcalls running.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
Changes since RFC v2:
* Add note about initialisation order change.
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Convert loongarch to use the arch_cpu_is_hotpluggable() helper rather
than arch_register_cpu(). Also remove the export as nothing should be
using arch_register_cpu() outside of the core kernel/acpi code.
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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LoongArch provides its own arch_unregister_cpu(). This clears the
hotpluggable flag, then unregisters the CPU.
It isn't necessary to clear the hotpluggable flag when unregistering
a cpu. unregister_cpu() writes NULL to the percpu cpu_sys_devices
pointer, meaning cpu_is_hotpluggable() will return false, as
get_cpu_device() has returned NULL.
Remove arch_unregister_cpu() and use the __weak version.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
Changes since RFC v3:
* Adapt for removal of EXPORT_SYMBOL()s
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Now that GENERIC_CPU_DEVICES calls arch_register_cpu(), which can be
overridden by the arch code, switch over to this to allow common code
to choose when the register_cpu() call is made.
This allows topology_init() to be removed.
This is an intermediate step to the logic being moved to drivers/acpi,
where GENERIC_CPU_DEVICES will do the work when booting with acpi=off.
This is a subtle change. Originally:
- on boot, topology_init() would have marked present CPUs that
io_master() is true for as hotplug-incapable.
- if a CPU is hotplugged that is an io_master(), it can later be
hot-unplugged.
The new behaviour is that any CPU that io_master() is true for will
now always be marked as hotplug-incapable, thus even if it was
hotplugged, it can no longer be hot-unplugged.
This patch also has the effect of moving the registration of CPUs from
subsys to driver core initialisation, prior to any initcalls running.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
Changes since RFC v2:
* Explain the change in behaviour in the patch description
(highlighted by Jonathan Cameron - thanks.) Add note about
initialisation order change.
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Convert x86 to use the arch_cpu_is_hotpluggable() helper rather than
arch_register_cpu().
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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Since the x86 version of arch_unregister_cpu() is the same as the weak
version, drop the x86 specific version.
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
Changes since RFC v3:
* Adapt to removal of EXPORT_SYMBOL()s
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Now that GENERIC_CPU_DEVICES calls arch_register_cpu(), which can be
overridden by the arch code, switch over to this to allow common code
to choose when the register_cpu() call is made.
x86's struct cpus come from struct x86_cpu, which has no other members
or users. Remove this and use the version defined by common code.
This is an intermediate step to the logic being moved to drivers/acpi,
where GENERIC_CPU_DEVICES will do the work when booting with acpi=off.
This patch also has the effect of moving the registration of CPUs from
subsys to driver core initialisation, prior to any initcalls running.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
----
Changes since RFC:
* Fixed the second copy of arch_register_cpu() used for non-hotplug
Changes since RFC v2:
* Remove duplicate of the weak generic arch_register_cpu(), spotted
by Jonathan Cameron. Add note about initialisation order change.
Changes since RFC v3:
* Adapt to removal of EXPORT_SYMBOL()s
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Convert arm64 to use the arch_cpu_is_hotpluggable() helper rather than
arch_register_cpu().
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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To allow ACPI's _STA value to hide CPUs that are present, but not
available to online right now due to VMM or firmware policy, the
register_cpu() call needs to be made by the ACPI machinery when ACPI
is in use. This allows it to hide CPUs that are unavailable from sysfs.
Switching to GENERIC_CPU_DEVICES is an intermediate step to allow all
five ACPI architectures to be modified at once.
Switch over to GENERIC_CPU_DEVICES, and provide an arch_register_cpu()
that populates the hotpluggable flag. arch_register_cpu() is also the
interface the ACPI machinery expects.
The struct cpu in struct cpuinfo_arm64 is never used directly, remove
it to use the one GENERIC_CPU_DEVICES provides.
This changes the CPUs visible in sysfs from possible to present, but
on arm64 smp_prepare_cpus() ensures these are the same.
This patch also has the effect of moving the registration of CPUs from
subsys to driver core initialisation, prior to any initcalls running.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
Changes since RFC v2:
* Add note about initialisation order change.
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loongarch, mips, parisc, riscv and sh all print a warning if
register_cpu() returns an error. Architectures that use
GENERIC_CPU_DEVICES call panic() instead.
Errors in this path indicate something is wrong with the firmware
description of the platform, but the kernel is able to keep running.
Downgrade this to a warning to make it easier to debug this issue.
This will allow architectures that switching over to GENERIC_CPU_DEVICES
to drop their warning, but keep the existing behaviour.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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NUMA systems require the node descriptions to be ready before CPUs are
registered. This is so that the node symlinks can be created in sysfs.
Currently no NUMA platform uses GENERIC_CPU_DEVICES, meaning that CPUs
are registered by arch code, instead of cpu_dev_init().
Move cpu_dev_init() after node_dev_init() so that NUMA architectures
can use GENERIC_CPU_DEVICES.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
Note: Jonathan's comment still needs addressing - see
https://lore.kernel.org/r/20230914121612.00006ac7@Huawei.com
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The differences between architecture specific implementations of
arch_register_cpu() are down to whether the CPU is hotpluggable or not.
Rather than overriding the weak version of arch_register_cpu(), provide
a function that can be used to provide this detail instead.
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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Add arch_unregister_cpu() to allow the ACPI machinery to call
unregister_cpu(). This is enough for arm64, riscv and loongarch, but
needs to be overridden by x86 and ia64 who need to do more work.
CC: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
An open question remains from the RFC v2 posting: should we provide a
__weak stub for !HOTPLUG_CPU as well, since in later patches ACPI may
reference this if the compiler doesn't optimise as we expect?
Changes since v1:
* Added CONFIG_HOTPLUG_CPU ifdeffery around unregister_cpu
Changes since RFC v2:
* Move earlier in the series
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Architectures often have extra per-cpu work that needs doing
before a CPU is registered, often to determine if a CPU is
hotpluggable.
To allow the ACPI architectures to use GENERIC_CPU_DEVICES, move
the cpu_register() call into arch_register_cpu(), which is made __weak
so architectures with extra work can override it.
This aligns with the way x86, ia64 and loongarch register hotplug CPUs
when they become present.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
Changes since RFC:
* Dropped __init from x86/ia64 arch_register_cpu()
Changes since RFC v2:
* Dropped unnecessary Loongarch asm/cpu.h changes
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Three of the five ACPI architectures create sysfs entries using
register_cpu() for present CPUs, whereas arm64, riscv and all
GENERIC_CPU_DEVICES do this for possible CPUs.
Registering a CPU is what causes them to show up in sysfs.
It makes very little sense to register all possible CPUs. Registering
a CPU is what triggers the udev notifications allowing user-space to
react to newly added CPUs.
To allow all five ACPI architectures to use GENERIC_CPU_DEVICES, change
it to use for_each_present_cpu().
Making the ACPI architectures use GENERIC_CPU_DEVICES is a pre-requisite
step to centralise their register_cpu() logic, before moving it into the
ACPI processor driver. When we add support for register CPUs from ACPI
in a later patch, we will avoid registering CPUs in this path.
Of the ACPI architectures that register possible CPUs, arm64 and riscv
do not support making possible CPUs present as they use the weak 'always
fails' version of arch_register_cpu().
Only two of the eight architectures that use GENERIC_CPU_DEVICES have a
distinction between present and possible CPUs.
The following architectures use GENERIC_CPU_DEVICES but are not SMP,
so possible == present:
* m68k
* microblaze
* nios2
The following architectures use GENERIC_CPU_DEVICES and consider
possible == present:
* csky: setup_smp()
* processor_probe() sets possible for all CPUs and present for all CPUs
except the boot cpu, which will have been done by
init/main.c::start_kernel().
um appears to be a subarchitecture of x86.
The remaining architecture using GENERIC_CPU_DEVICES are:
* openrisc and hexagon:
where smp_init_cpus() makes all CPUs < NR_CPUS possible,
whereas smp_prepare_cpus() only makes CPUs < setup_max_cpus present.
After this change, openrisc and hexagon systems that use the max_cpus
command line argument would not see the other CPUs present in sysfs.
This should not be a problem as these CPUs can't be brought online as
_cpu_up() checks cpu_present().
After this change, only CPUs which are present appear in sysfs.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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Neither arm64 nor riscv support physical hotadd of CPUs that were not
present at boot. For arm64 much of the platform description is in static
tables which do not have update methods. arm64 does support HOTPLUG_CPU,
which is backed by a firmware interface to turn CPUs on and off.
acpi_processor_hotadd_init() and acpi_processor_remove() are for adding
and removing CPUs that were not present at boot. arm64 systems that do this
are not supported as there is currently insufficient information in the
platform description. (e.g. did the GICR get removed too?)
arm64 currently relies on the MADT enabled flag check in map_gicc_mpidr()
to prevent CPUs that were not described as present at boot from being
added to the system. Similarly, riscv relies on the same check in
map_rintc_hartid(). Both architectures also rely on the weak 'always fails'
definitions of acpi_map_cpu() and arch_register_cpu().
Subsequent changes will redefine ACPI_HOTPLUG_CPU as making possible
CPUs present. Neither arm64 nor riscv support this.
Disable ACPI_HOTPLUG_CPU for arm64 and riscv by removing 'default y' and
selecting it on the other three ACPI architectures. This allows the weak
definitions of some symbols to be removed.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
Changes since RFC:
* Expanded conditions to avoid ACPI_HOTPLUG_CPU being enabled when
HOTPLUG_CPU isn't.
Changes since RFC v3:
* Dropped ia64 changes
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arch_register_cpu() and arch_unregister_cpu() are not used by anything
that can be a module - they are used by drivers/base/cpu.c and
drivers/acpi/acpi_processor.c, neither of which can be a module.
Remove the exports.
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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arch_register_cpu() and arch_unregister_cpu() are not used by anything
that can be a module - they are used by drivers/base/cpu.c and
drivers/acpi/acpi_processor.c, neither of which can be a module.
Remove the exports.
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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intel_epb_init() is called as a subsys_initcall() to register cpuhp
callbacks. The callbacks make use of get_cpu_device() which will return
NULL unless register_cpu() has been called. register_cpu() is called
from topology_init(), which is also a subsys_initcall().
This is fragile. Moving the register_cpu() to a different
subsys_initcall() leads to a NULL dereference during boot.
Make intel_epb_init() a late_initcall(), user-space can't provide a
policy before this point anyway.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
subsys_initcall_sync() would be an option, but moving the register_cpu()
calls into ACPI also means adding a safety net for CPUs that are online
but not described properly by firmware. This lives in subsys_initcall_sync().
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register_cpu_capacity_sysctl() adds a property to sysfs that describes
the CPUs capacity. This is done from a subsys_initcall() that assumes
all possible CPUs are registered.
With CPU hotplug, possible CPUs aren't registered until they become
present, (or for arm64 enabled). This leads to messages during boot:
| register_cpu_capacity_sysctl: too early to get CPU1 device!
and once these CPUs are added to the system, the file is missing.
Move this to a cpuhp callback, so that the file is created once
CPUs are brought online. This covers CPUs that are added late by
mechanisms like hotplug.
One observable difference is the file is now missing for offline CPUs.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
If the offline CPUs thing is a problem for the tools that consume
this value, we'd need to move cpu_capacity to be part of cpu.c's
common_cpu_attr_groups. However, attempts to discuss this just end
up in a black hole, so this is a non-starter. Thus, if this needs
to be done, it can be done as a separate patch.
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The commands should be sorted inside the group definition.
Fix the ordering so we won't get following warning:
WARN_ON(iwl_cmd_groups_verify_sorted(trans_cfg))
Link: https://lore.kernel.org/regressions/2fa930bb-54dd-4942-a88d-05a47c8e9731@gmail.com/
Link: https://lore.kernel.org/linux-wireless/CAHk-=wix6kqQ5vHZXjOPpZBfM7mMm9bBZxi2Jh7XnaKCqVf94w@mail.gmail.com/
Fixes: b6e3d1ba4fcf ("wifi: iwlwifi: mvm: implement new firmware API for statistics")
Tested-by: Niklāvs Koļesņikovs <pinkflames.linux@gmail.com>
Tested-by: Damian Tometzki <damian@riscv-rocks.de>
Acked-by: Kalle Valo <kvalo@kernel.org>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux
Pull parisc architecture fixes from Helge Deller:
- Include the upper 5 address bits when inserting TLB entries on a
64-bit kernel.
On physical machines those are ignored, but in qemu it's nice to have
them included and to be correct.
- Stop the 64-bit kernel and show a warning if someone tries to boot on
a machine with a 32-bit CPU
- Fix a "no previous prototype" warning in parport-gsc
* tag 'parisc-for-6.7-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
parisc: Prevent booting 64-bit kernels on PA1.x machines
parport: gsc: mark init function static
parisc/pgtable: Do not drop upper 5 address bits of physical address
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git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
Pull LoongArch updates from Huacai Chen:
- support PREEMPT_DYNAMIC with static keys
- relax memory ordering for atomic operations
- support BPF CPU v4 instructions for LoongArch
- some build and runtime warning fixes
* tag 'loongarch-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson:
selftests/bpf: Enable cpu v4 tests for LoongArch
LoongArch: BPF: Support signed mod instructions
LoongArch: BPF: Support signed div instructions
LoongArch: BPF: Support 32-bit offset jmp instructions
LoongArch: BPF: Support unconditional bswap instructions
LoongArch: BPF: Support sign-extension mov instructions
LoongArch: BPF: Support sign-extension load instructions
LoongArch: Add more instruction opcodes and emit_* helpers
LoongArch/smp: Call rcutree_report_cpu_starting() earlier
LoongArch: Relax memory ordering for atomic operations
LoongArch: Mark __percpu functions as always inline
LoongArch: Disable module from accessing external data directly
LoongArch: Support PREEMPT_DYNAMIC with static keys
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git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Michael Ellerman:
- Finish a refactor of pgprot_framebuffer() which dependend
on some changes that were merged via the drm tree
- Fix some kernel-doc warnings to quieten the bots
Thanks to Nathan Lynch and Thomas Zimmermann.
* tag 'powerpc-6.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/rtas: Fix ppc_rtas_rmo_buf_show() kernel-doc
powerpc/pseries/rtas-work-area: Fix rtas_work_area_reserve_arena() kernel-doc
powerpc/fb: Call internal __phys_mem_access_prot() in fbdev code
powerpc: Remove file parameter from phys_mem_access_prot()
powerpc/machdep: Remove trailing whitespaces
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git://git.samba.org/sfrench/cifs-2.6
Pull smb client fixes from Steve French:
- ctime caching fix (for setxattr)
- encryption fix
- DNS resolver mount fix
- debugging improvements
- multichannel fixes including cases where server stops or starts
supporting multichannel after mount
- reconnect fix
- minor cleanups
* tag '6.7-rc-smb3-client-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6:
cifs: update internal module version number for cifs.ko
cifs: handle when server stops supporting multichannel
cifs: handle when server starts supporting multichannel
Missing field not being returned in ioctl CIFS_IOC_GET_MNT_INFO
smb3: allow dumping session and tcon id to improve stats analysis and debugging
smb: client: fix mount when dns_resolver key is not available
smb3: fix caching of ctime on setxattr
smb3: minor cleanup of session handling code
cifs: reconnect work should have reference on server struct
cifs: do not pass cifs_sb when trying to add channels
cifs: account for primary channel in the interface list
cifs: distribute channels across interfaces based on speed
cifs: handle cases where a channel is closed
smb3: more minor cleanups for session handling routines
smb3: minor RDMA cleanup
cifs: Fix encryption of cleared, but unset rq_iter data buffers
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git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull probes fixes from Masami Hiramatsu:
- Documentation update: Add a note about argument and return value
fetching is the best effort because it depends on the type.
- objpool: Fix to make internal global variables static in
test_objpool.c.
- kprobes: Unify kprobes_exceptions_nofify() prototypes. There are the
same prototypes in asm/kprobes.h for some architectures, but some of
them are missing the prototype and it causes a warning. So move the
prototype into linux/kprobes.h.
- tracing: Fix to check the tracepoint event and return event at
parsing stage. The tracepoint event doesn't support %return but if
$retval exists, it will be converted to %return silently. This finds
that case and rejects it.
- tracing: Fix the order of the descriptions about the parameters of
__kprobe_event_gen_cmd_start() to be consistent with the argument
list of the function.
* tag 'probes-fixes-v6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing/kprobes: Fix the order of argument descriptions
tracing: fprobe-event: Fix to check tracepoint event and return
kprobes: unify kprobes_exceptions_nofify() prototypes
lib: test_objpool: make global variables static
Documentation: tracing: Add a note about argument and retval access
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git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev
Pull fbdev fixes and cleanups from Helge Deller:
- fix double free and resource leaks in imsttfb
- lots of remove callback cleanups and section mismatch fixes in
omapfb, amifb and atmel_lcdfb
- error code fix and memparse simplification in omapfb
* tag 'fbdev-for-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev: (31 commits)
fbdev: fsl-diu-fb: mark wr_reg_wa() static
fbdev: amifb: Convert to platform remove callback returning void
fbdev: amifb: Mark driver struct with __refdata to prevent section mismatch warning
fbdev: hyperv_fb: fix uninitialized local variable use
fbdev: omapfb/tpd12s015: Convert to platform remove callback returning void
fbdev: omapfb/tfp410: Convert to platform remove callback returning void
fbdev: omapfb/sharp-ls037v7dw01: Convert to platform remove callback returning void
fbdev: omapfb/opa362: Convert to platform remove callback returning void
fbdev: omapfb/hdmi: Convert to platform remove callback returning void
fbdev: omapfb/dvi: Convert to platform remove callback returning void
fbdev: omapfb/dsi-cm: Convert to platform remove callback returning void
fbdev: omapfb/dpi: Convert to platform remove callback returning void
fbdev: omapfb/analog-tv: Convert to platform remove callback returning void
fbdev: atmel_lcdfb: Convert to platform remove callback returning void
fbdev: omapfb/tpd12s015: Don't put .remove() in .exit.text and drop suppress_bind_attrs
fbdev: omapfb/tfp410: Don't put .remove() in .exit.text and drop suppress_bind_attrs
fbdev: omapfb/sharp-ls037v7dw01: Don't put .remove() in .exit.text and drop suppress_bind_attrs
fbdev: omapfb/opa362: Don't put .remove() in .exit.text and drop suppress_bind_attrs
fbdev: omapfb/hdmi: Don't put .remove() in .exit.text and drop suppress_bind_attrs
fbdev: omapfb/dvi: Don't put .remove() in .exit.text and drop suppress_bind_attrs
...
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