arm64: sdei: abort running SDEI handlers during crash

Interrupts are blocked in SDEI context, per the SDEI spec: "The client
interrupts cannot preempt the event handler." If we crashed in the SDEI
h

arm64: sdei: abort running SDEI handlers during crash

Interrupts are blocked in SDEI context, per the SDEI spec: "The client
interrupts cannot preempt the event handler." If we crashed in the SDEI
handler-running context (as with ACPI's AGDI) then we need to clean up the
SDEI state before proceeding to the crash kernel so that the crash kernel
can have working interrupts.

Track the active SDEI handler per-cpu so that we can COMPLETE_AND_RESUME
the handler, discarding the interrupted context.

Fixes: f5df26961853 ("arm64: kernel: Add arch-specific SDEI entry code and CPU masking")
Signed-off-by: D Scott Phillips <scott@os.amperecomputing.com>
Cc: stable@vger.kernel.org
Reviewed-by: James Morse <james.morse@arm.com>
Tested-by: Mihai Carabas <mihai.carabas@oracle.com>
Link: https://lore.kernel.org/r/20230627002939.2758-1-scott@os.amperecomputing.com
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

firmware: arm_sdei: Fix sleep from invalid context BUG

Running a preempt-rt (v6.2-rc3-rt1) based kernel on an Ampere Altra
triggers:

BUG: sleeping function called from invalid context at kernel/l

firmware: arm_sdei: Fix sleep from invalid context BUG

Running a preempt-rt (v6.2-rc3-rt1) based kernel on an Ampere Altra
triggers:

BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46
in_atomic(): 0, irqs_disabled(): 128, non_block: 0, pid: 24, name: cpuhp/0
preempt_count: 0, expected: 0
RCU nest depth: 0, expected: 0
3 locks held by cpuhp/0/24:
#0: ffffda30217c70d0 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x5c/0x248
#1: ffffda30217c7120 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x5c/0x248
#2: ffffda3021c711f0 (sdei_list_lock){....}-{3:3}, at: sdei_cpuhp_up+0x3c/0x130
irq event stamp: 36
hardirqs last enabled at (35): [<ffffda301e85b7bc>] finish_task_switch+0xb4/0x2b0
hardirqs last disabled at (36): [<ffffda301e812fec>] cpuhp_thread_fun+0x21c/0x248
softirqs last enabled at (0): [<ffffda301e80b184>] copy_process+0x63c/0x1ac0
softirqs last disabled at (0): [<0000000000000000>] 0x0
CPU: 0 PID: 24 Comm: cpuhp/0 Not tainted 5.19.0-rc3-rt5-[...]
Hardware name: WIWYNN Mt.Jade Server [...]
Call trace:
dump_backtrace+0x114/0x120
show_stack+0x20/0x70
dump_stack_lvl+0x9c/0xd8
dump_stack+0x18/0x34
__might_resched+0x188/0x228
rt_spin_lock+0x70/0x120
sdei_cpuhp_up+0x3c/0x130
cpuhp_invoke_callback+0x250/0xf08
cpuhp_thread_fun+0x120/0x248
smpboot_thread_fn+0x280/0x320
kthread+0x130/0x140
ret_from_fork+0x10/0x20

sdei_cpuhp_up() is called in the STARTING hotplug section,
which runs with interrupts disabled. Use a CPUHP_AP_ONLINE_DYN entry
instead to execute the cpuhp cb later, with preemption enabled.

SDEI originally got its own cpuhp slot to allow interacting
with perf. It got superseded by pNMI and this early slot is not
relevant anymore. [1]

Some SDEI calls (e.g. SDEI_1_0_FN_SDEI_PE_MASK) take actions on the
calling CPU. It is checked that preemption is disabled for them.
_ONLINE cpuhp cb are executed in the 'per CPU hotplug thread'.
Preemption is enabled in those threads, but their cpumask is limited
to 1 CPU.
Move 'WARN_ON_ONCE(preemptible())' statements so that SDEI cpuhp cb
don't trigger them.

Also add a check for the SDEI_1_0_FN_SDEI_PRIVATE_RESET SDEI call
which acts on the calling CPU.

[1]:
https://lore.kernel.org/all/5813b8c5-ae3e-87fd-fccc-94c9cd08816d@arm.com/

Suggested-by: James Morse <james.morse@arm.com>
Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/r/20230216084920.144064-1-pierre.gondois@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

ACPI: APEI: explicit init of HEST and GHES in apci_init()

From commit e147133a42cb ("ACPI / APEI: Make hest.c manage the estatus
memory pool") was merged, ghes_init() relies on acpi_hest_init() to m

ACPI: APEI: explicit init of HEST and GHES in apci_init()

From commit e147133a42cb ("ACPI / APEI: Make hest.c manage the estatus
memory pool") was merged, ghes_init() relies on acpi_hest_init() to manage
the estatus memory pool. On the other hand, ghes_init() relies on
sdei_init() to detect the SDEI version and (un)register events. The
dependencies are as follows:

ghes_init() => acpi_hest_init() => acpi_bus_init() => acpi_init()
ghes_init() => sdei_init()

HEST is not PCI-specific and initcall ordering is implicit and not
well-defined within a level.

Based on above, remove acpi_hest_init() from acpi_pci_root_init() and
convert ghes_init() and sdei_init() from initcalls to explicit calls in the
following order:

acpi_hest_init()
ghes_init()
sdei_init()

Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

show more ...

ACPI: APEI: explicit init of HEST and GHES in apci_init()

[ Upstream commit dc4e8c07e9e2f69387579c49caca26ba239f7270 ]

From commit e147133a42cb ("ACPI / APEI: Make hest.c manage the estatus
memory

ACPI: APEI: explicit init of HEST and GHES in apci_init()

[ Upstream commit dc4e8c07e9e2f69387579c49caca26ba239f7270 ]

From commit e147133a42cb ("ACPI / APEI: Make hest.c manage the estatus
memory pool") was merged, ghes_init() relies on acpi_hest_init() to manage
the estatus memory pool. On the other hand, ghes_init() relies on
sdei_init() to detect the SDEI version and (un)register events. The
dependencies are as follows:

ghes_init() => acpi_hest_init() => acpi_bus_init() => acpi_init()
ghes_init() => sdei_init()

HEST is not PCI-specific and initcall ordering is implicit and not
well-defined within a level.

Based on above, remove acpi_hest_init() from acpi_pci_root_init() and
convert ghes_init() and sdei_init() from initcalls to explicit calls in the
following order:

acpi_hest_init()
ghes_init()
sdei_init()

Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

arm64: sdei: move uaccess logic to arch/arm64/

The SDEI support code is split across arch/arm64/ and drivers/firmware/,
largley this is split so that the arch-specific portions are under
arch/arm64,

arm64: sdei: move uaccess logic to arch/arm64/

The SDEI support code is split across arch/arm64/ and drivers/firmware/,
largley this is split so that the arch-specific portions are under
arch/arm64, and the management logic is under drivers/firmware/.
However, exception entry fixups are currently under drivers/firmware.

Let's move the exception entry fixups under arch/arm64/. This
de-clutters the management logic, and puts all the arch-specific
portions in one place. Doing this also allows the fixups to be applied
earlier, so things like PAN and UAO will be in a known good state before
we run other logic. This will also make subsequent refactoring easier.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201202131558.39270-2-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

show more ...

firmware: arm_sdei: Remove _sdei_event_unregister()

_sdei_event_unregister() is called by sdei_event_unregister() and
sdei_device_freeze(). _sdei_event_unregister() covers the shared
and private eve

firmware: arm_sdei: Remove _sdei_event_unregister()

_sdei_event_unregister() is called by sdei_event_unregister() and
sdei_device_freeze(). _sdei_event_unregister() covers the shared
and private events, but sdei_device_freeze() only covers the shared
events. So the logic to cover the private events isn't needed by
sdei_device_freeze().

sdei_event_unregister sdei_device_freeze
_sdei_event_unregister sdei_unregister_shared
_sdei_event_unregister

This removes _sdei_event_unregister(). Its logic is moved to its
callers accordingly. This shouldn't cause any logical changes.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/r/20200922130423.10173-14-gshan@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

firmware: arm_sdei: Remove _sdei_event_register()

The function _sdei_event_register() is called by sdei_event_register()
and sdei_device_thaw() as the following functional call chain shows.
_sdei_ev

firmware: arm_sdei: Remove _sdei_event_register()

The function _sdei_event_register() is called by sdei_event_register()
and sdei_device_thaw() as the following functional call chain shows.
_sdei_event_register() covers the shared and private events, but
sdei_device_thaw() only covers the shared events. So the logic to
cover the private events in _sdei_event_register() isn't needed by
sdei_device_thaw().

Similarly, sdei_reregister_event_llocked() covers the shared and
private events in the regard of reenablement. The logic to cover
the private events isn't needed by sdei_device_thaw() either.

sdei_event_register sdei_device_thaw
_sdei_event_register sdei_reregister_shared
sdei_reregister_event_llocked
_sdei_event_register

This removes _sdei_event_register() and sdei_reregister_event_llocked().
Their logic is moved to sdei_event_register() and sdei_reregister_shared().
This shouldn't cause any logical changes.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/r/20200922130423.10173-13-gshan@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

firmware: arm_sdei: Introduce sdei_do_local_call()

During the CPU hotplug, the private events are registered, enabled
or unregistered on the specific CPU. It repeats the same steps:
initializing cro

firmware: arm_sdei: Introduce sdei_do_local_call()

During the CPU hotplug, the private events are registered, enabled
or unregistered on the specific CPU. It repeats the same steps:
initializing cross call argument, make function call on local CPU,
check the returned error.

This introduces sdei_do_local_call() to cover the first steps. The
other benefit is to make CROSSCALL_INIT and struct sdei_crosscall_args
are only visible to sdei_do_{cross, local}_call().

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/r/20200922130423.10173-12-gshan@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

firmware: arm_sdei: Cleanup on cross call function

This applies cleanup on the cross call functions, no functional
changes are introduced:

* Wrap the code block of CROSSCALL_INIT inside "do { }

firmware: arm_sdei: Cleanup on cross call function

This applies cleanup on the cross call functions, no functional
changes are introduced:

* Wrap the code block of CROSSCALL_INIT inside "do { } while (0)"
as linux kernel usually does. Otherwise, scripts/checkpatch.pl
reports warning regarding this.
* Use smp_call_func_t for @fn argument in sdei_do_cross_call()
as the function is called on target CPU(s).
* Remove unnecessary space before @event in sdei_do_cross_call()

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/r/20200922130423.10173-11-gshan@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

firmware: arm_sdei: Remove while loop in sdei_event_unregister()

This removes the unnecessary while loop in sdei_event_unregister()
because of the following two reasons. This shouldn't cause any
fun

firmware: arm_sdei: Remove while loop in sdei_event_unregister()

This removes the unnecessary while loop in sdei_event_unregister()
because of the following two reasons. This shouldn't cause any
functional changes.

* The while loop is executed for once, meaning it's not needed
in theory.
* With the while loop removed, the nested statements can be
avoid to make the code a bit cleaner.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20200922130423.10173-10-gshan@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

firmware: arm_sdei: Remove while loop in sdei_event_register()

This removes the unnecessary while loop in sdei_event_register()
because of the following two reasons. This shouldn't cause any
functio

firmware: arm_sdei: Remove while loop in sdei_event_register()

This removes the unnecessary while loop in sdei_event_register()
because of the following two reasons. This shouldn't cause any
functional changes.

* The while loop is executed for once, meaning it's not needed
in theory.
* With the while loop removed, the nested statements can be
avoid to make the code a bit cleaner.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20200922130423.10173-9-gshan@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

firmware: arm_sdei: Remove redundant error message in sdei_probe()

This removes the redundant error message in sdei_probe() because
the case can be identified from the errno in next error message.

firmware: arm_sdei: Remove redundant error message in sdei_probe()

This removes the redundant error message in sdei_probe() because
the case can be identified from the errno in next error message.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/r/20200922130423.10173-8-gshan@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

firmware: arm_sdei: Remove duplicate check in sdei_get_conduit()

The following two checks are duplicate because @acpi_disabled doesn't
depend on CONFIG_ACPI. So the duplicate check (IS_ENABLED(CONFI

firmware: arm_sdei: Remove duplicate check in sdei_get_conduit()

The following two checks are duplicate because @acpi_disabled doesn't
depend on CONFIG_ACPI. So the duplicate check (IS_ENABLED(CONFIG_ACPI))
can be dropped. More details is provided to keep the commit log complete:

* @acpi_disabled is defined in arch/arm64/kernel/acpi.c when
CONFIG_ACPI is enabled.
* @acpi_disabled in defined in include/acpi.h when CONFIG_ACPI
is disabled.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/r/20200922130423.10173-7-gshan@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

firmware: arm_sdei: Unregister driver on error in sdei_init()

The SDEI platform device is created from device-tree node or ACPI
(SDEI) table. For the later case, the platform device is created
expli

firmware: arm_sdei: Unregister driver on error in sdei_init()

The SDEI platform device is created from device-tree node or ACPI
(SDEI) table. For the later case, the platform device is created
explicitly by this module. It'd better to unregister the driver on
failure to create the device to keep the symmetry. The driver, owned
by this module, isn't needed if the device isn't existing.

Besides, the errno (@ret) should be updated accordingly in this
case.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/r/20200922130423.10173-6-gshan@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

firmware: arm_sdei: Avoid nested statements in sdei_init()

In sdei_init(), the nested statements can be avoided by bailing
on error from platform_driver_register() or absent ACPI SDEI table.
With it

firmware: arm_sdei: Avoid nested statements in sdei_init()

In sdei_init(), the nested statements can be avoided by bailing
on error from platform_driver_register() or absent ACPI SDEI table.
With it, the code looks a bit more readable.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/r/20200922130423.10173-5-gshan@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

firmware: arm_sdei: Retrieve event number from event instance

In sdei_event_create(), the event number is retrieved from the
variable @event_num for the shared event. The event number was
stored in

firmware: arm_sdei: Retrieve event number from event instance

In sdei_event_create(), the event number is retrieved from the
variable @event_num for the shared event. The event number was
stored in the event instance. So we can fetch it from the event
instance, similar to what we're doing for the private event.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/r/20200922130423.10173-4-gshan@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

firmware: arm_sdei: Common block for failing path in sdei_event_create()

There are multiple calls of kfree(event) in the failing path of
sdei_event_create() to free the SDEI event. It means we need

firmware: arm_sdei: Common block for failing path in sdei_event_create()

There are multiple calls of kfree(event) in the failing path of
sdei_event_create() to free the SDEI event. It means we need to
call it again when adding more code in the failing path. It's
prone to miss doing that and introduce memory leakage.

This introduces common block for failing path in sdei_event_create()
to resolve the issue. This shouldn't cause functional changes.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/r/20200922130423.10173-3-gshan@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

firmware: arm_sdei: Remove sdei_is_err()

sdei_is_err() is only called by sdei_to_linux_errno(). The logic of
checking on the error number is common to them. They can be combined
finely.

This remove

firmware: arm_sdei: Remove sdei_is_err()

sdei_is_err() is only called by sdei_to_linux_errno(). The logic of
checking on the error number is common to them. They can be combined
finely.

This removes sdei_is_err() and its logic is combined to the function
sdei_to_linux_errno(). Also, the assignment of @err to zero is also
dropped in invoke_sdei_fn() because it's always overridden afterwards.
This shouldn't cause functional changes.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: James Morse <james.morse@arm.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20200922130423.10173-2-gshan@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

uaccess: add force_uaccess_{begin,end} helpers

Add helpers to wrap the get_fs/set_fs magic for undoing any damange done
by set_fs(KERNEL_DS). There is no real functional benefit, but this
documents

uaccess: add force_uaccess_{begin,end} helpers

Add helpers to wrap the get_fs/set_fs magic for undoing any damange done
by set_fs(KERNEL_DS). There is no real functional benefit, but this
documents the intent of these calls better, and will allow stubbing the
functions out easily for kernels builds that do not allow address space
overrides in the future.

[hch@lst.de: drop two incorrect hunks, fix a commit log typo]
Link: http://lkml.kernel.org/r/20200714105505.935079-6-hch@lst.de

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Greentime Hu <green.hu@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Link: http://lkml.kernel.org/r/20200710135706.537715-6-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

show more ...

firmware: arm_sdei: Document the motivation behind these set_fs() calls

The SDEI handler save/restores the addr_limit using set_fs(). It isn't
very clear why. The reason is to mirror the arch code's

firmware: arm_sdei: Document the motivation behind these set_fs() calls

The SDEI handler save/restores the addr_limit using set_fs(). It isn't
very clear why. The reason is to mirror the arch code's entry assembly.
The arch code does this because perf may access user-space, and
inheriting the addr_limit may be a problem.

Add a comment explaining why this is here.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Morse <james.morse@arm.com>
Link: https://bugs.chromium.org/p/project-zero/issues/detail?id=822
Link: https://lore.kernel.org/r/20200519182108.13693-4-james.morse@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

firmware: arm_sdei: remove unused interfaces

The export symbols to register/unregister and enable/disable events
aren't used upstream, remove them.

[ dropped the parts of Christoph's patch that mad

firmware: arm_sdei: remove unused interfaces

The export symbols to register/unregister and enable/disable events
aren't used upstream, remove them.

[ dropped the parts of Christoph's patch that made the API static too ]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/linux-arm-kernel/20200504164224.2842960-1-hch@lst.de/
Link: https://lore.kernel.org/r/20200519182108.13693-3-james.morse@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

firmware: arm_sdei: Put the SDEI table after using it

The acpi_get_table() should be coupled with acpi_put_table() if
the mapped table is not used for runtime after the initialization
to release the

firmware: arm_sdei: Put the SDEI table after using it

The acpi_get_table() should be coupled with acpi_put_table() if
the mapped table is not used for runtime after the initialization
to release the table mapping, put the SDEI table after using it.

Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/linux-arm-kernel/1589021566-46373-1-git-send-email-guohanjun@huawei.com/
Link: https://lore.kernel.org/r/20200519182108.13693-2-james.morse@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

firmware: arm_sdei: Drop check for /firmware/ node and always register driver

As with most of the drivers, let us register this driver unconditionally
by dropping the checks for presence of firmware

firmware: arm_sdei: Drop check for /firmware/ node and always register driver

As with most of the drivers, let us register this driver unconditionally
by dropping the checks for presence of firmware nodes(DT) or entries(ACPI).

Further, as mentioned in the commit acafce48b07b ("firmware: arm_sdei:
Fix DT platform device creation"), the core takes care of creation of
platform device when the appropriate device node is found and probe
is called accordingly.

Let us check only for the presence of ACPI firmware entry before creating
the platform device and flag warning if we fail.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Cc: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/r/20200422122823.1390-1-sudeep.holla@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

firmware: arm_sdei: clean up sdei_event_create()

Function sdei_event_find() is always called in sdei_event_create(), but
it is already called in sdei_event_register(). This code is trying to
avoid a

firmware: arm_sdei: clean up sdei_event_create()

Function sdei_event_find() is always called in sdei_event_create(), but
it is already called in sdei_event_register(). This code is trying to
avoid a double-create of the same event, which can't happen as we still
hold the sdei_events_lock. We can remove this needless sdei_event_find()
call.

Signed-off-by: Liguang Zhang <zhangliguang@linux.alibaba.com>
[expanded commit message]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

show more ...

firmware: arm_sdei: Use cpus_read_lock() to avoid races with cpuhp

SDEI has private events that need registering and enabling on each CPU.
CPUs can come and go while we are trying to do this. SDEI t

firmware: arm_sdei: Use cpus_read_lock() to avoid races with cpuhp

SDEI has private events that need registering and enabling on each CPU.
CPUs can come and go while we are trying to do this. SDEI tries to avoid
these problems by setting the reregister flag before the register call,
so any CPUs that come online register the event too. Sticking plaster
like this doesn't work, as if the register call fails, a CPU that
subsequently comes online will register the event before reregister
is cleared.

Take cpus_read_lock() around the register and enable calls. We don't
want surprise CPUs to do the wrong thing if they race with these calls
failing.

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

show more ...