2
0
mirror of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2025-09-04 20:19:47 +08:00
Commit Graph

298 Commits

Author SHA1 Message Date
Brian Norris
2b32fc8ff0 genirq/cpuhotplug: Rebalance managed interrupts across multi-CPU hotplug
Commit 788019eb55 ("genirq: Retain disable depth for managed interrupts
across CPU hotplug") intended to only decrement the disable depth once per
managed shutdown, but instead it decrements for each CPU hotplug in the
affinity mask, until its depth reaches a point where it finally gets
re-started.

For example, consider:

1. Interrupt is affine to CPU {M,N}
2. disable_irq() -> depth is 1
3. CPU M goes offline -> interrupt migrates to CPU N / depth is still 1
4. CPU N goes offline -> irq_shutdown() / depth is 2
5. CPU N goes online
    -> irq_restore_affinity_of_irq()
       -> irqd_is_managed_and_shutdown()==true
          -> irq_startup_managed() -> depth is 1
6. CPU M goes online
    -> irq_restore_affinity_of_irq()
       -> irqd_is_managed_and_shutdown()==true
          -> irq_startup_managed() -> depth is 0
          *** BUG: driver expects the interrupt is still disabled ***
             -> irq_startup() -> irqd_clr_managed_shutdown()
7. enable_irq() -> depth underflow / unbalanced enable_irq() warning

This should clear the managed-shutdown flag at step 6, so that further
hotplugs don't cause further imbalance.

Note: It might be cleaner to also remove the irqd_clr_managed_shutdown()
invocation from __irq_startup_managed(). But this is currently not possible
because of irq_update_affinity_desc() as it sets IRQD_MANAGED_SHUTDOWN and
expects irq_startup() to clear it.

Fixes: 788019eb55 ("genirq: Retain disable depth for managed interrupts across CPU hotplug")
Reported-by: Aleksandrs Vinarskis <alex.vinarskis@gmail.com>
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Aleksandrs Vinarskis <alex.vinarskis@gmail.com>
Link: https://lore.kernel.org/all/20250612183303.3433234-2-briannorris@chromium.org
2025-06-13 15:13:35 +02:00
Brian Norris
788019eb55 genirq: Retain disable depth for managed interrupts across CPU hotplug
Affinity-managed interrupts can be shut down and restarted during CPU
hotunplug/plug. Thereby the interrupt may be left in an unexpected state.
Specifically:

 1. Interrupt is affine to CPU N
 2. disable_irq() -> depth is 1
 3. CPU N goes offline
 4. irq_shutdown() -> depth is set to 1 (again)
 5. CPU N goes online
 6. irq_startup() -> depth is set to 0 (BUG! driver expects that the interrupt
    		     	      	        still disabled)
 7. enable_irq() -> depth underflow / unbalanced enable_irq() warning

This is only a problem for managed interrupts and CPU hotplug, all other
cases like request()/free()/request() truly needs to reset a possibly stale
disable depth value.

Provide a startup function, which takes the disable depth into account, and
invoked it for the managed interrupts in the CPU hotplug path.

This requires to change irq_shutdown() to do a depth increment instead of
setting it to 1, which allows to retain the disable depth, but is harmless
for the other code paths using irq_startup(), which will still reset the
disable depth unconditionally to keep the original correct behaviour.

A kunit tests will be added separately to cover some of these aspects.

[ tglx: Massaged changelog ]

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250514201353.3481400-2-briannorris@chromium.org
2025-05-15 16:44:25 +02:00
Thomas Gleixner
c1ab449df8 genirq: Fix inverted condition in handle_nested_irq()
Marek reported that the rework of handle_nested_irq() introduced a inverted
condition, which prevents handling of interrupts. Fix it up.

Fixes: 2ef2e13094 ("genirq/chip: Rework handle_nested_irq()")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Closes: https://lore.kernel/org/all/46ed4040-ca11-4157-8bd7-13c04c113734@samsung.com
2025-05-09 20:42:26 +02:00
Thomas Gleixner
95a3645893 genirq/chip: Rework irq_modify_status()
Use the new guards to get and lock the interrupt descriptor and tidy up the
code.

Fixup the kernel doc comment while at it.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250429065421.650454052@linutronix.de
2025-05-07 09:08:14 +02:00
Thomas Gleixner
5cd05f3e23 genirq/chip: Rework irq_set_handler() variants
Use the new guards to get and lock the interrupt descriptor and tidy up the
code.

Fixup the kernel doc comment while at it.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250429065421.590753128@linutronix.de
2025-05-07 09:08:14 +02:00
Thomas Gleixner
b3801ddc68 genirq/chip: Rework irq_set_chip_data()
Use the new guards to get and lock the interrupt descriptor and tidy up the
code.

Fixup the kernel doc comment while at it.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250429065421.532308759@linutronix.de
2025-05-07 09:08:14 +02:00
Thomas Gleixner
c836e5a70c genirq/chip: Rework irq_set_msi_desc_off()
Use the new guards to get and lock the interrupt descriptor and tidy up the
code.

Fixup the kernel doc comment while at it.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250429065421.473563978@linutronix.de
2025-05-07 09:08:14 +02:00
Thomas Gleixner
321a0fdf13 genirq/chip: Rework irq_set_handler_data()
Use the new guards to get and lock the interrupt descriptor and tidy up the
code.

Fixup the kernel doc comment while at it.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250429065421.415072350@linutronix.de
2025-05-07 09:08:14 +02:00
Thomas Gleixner
fa870e0f35 genirq/chip: Rework irq_set_irq_type()
Use the new guards to get and lock the interrupt descriptor and tidy up the
code.

Fixup the kernel doc comment while at it.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250429065421.355673840@linutronix.de
2025-05-07 09:08:13 +02:00
Thomas Gleixner
46ff4d11f0 genirq/chip: Rework irq_set_chip()
Use the new guards to get and lock the interrupt descriptor and tidy up the
code.

Fixup the kernel doc comment while at it.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250429065421.295400891@linutronix.de
2025-05-07 09:08:13 +02:00
Thomas Gleixner
e7c6542557 genirq/chip: Use lock guards where applicable
Convert all lock/unlock pairs to guards and tidy up the code.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250429065421.236248749@linutronix.de
2025-05-07 09:08:13 +02:00
Thomas Gleixner
f71d7c45ed genirq/chip: Rework handle_fasteoi_mask_irq()
Use the new helpers to decide whether the interrupt should be handled and
switch the descriptor locking to guard().

Note: The mask_irq() operation in the second condition was redundant as the
interrupt is already masked right at the beginning of the function.

Fixup the kernel doc comment while at it.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250429065421.175652864@linutronix.de
2025-05-07 09:08:13 +02:00
Thomas Gleixner
2beb01cbb7 genirq/chip: Rework handle_fasteoi_ack_irq()
Use the new helpers to decide whether the interrupt should be handled and
switch the descriptor locking to guard().

Fixup the kernel doc comment while at it.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250429065421.105015800@linutronix.de
2025-05-07 09:08:13 +02:00
Thomas Gleixner
2d46aea52c genirq/chip: Rework handle_edge_irq()
Use the new helpers to decide whether the interrupt should be handled and
switch the descriptor locking to guard().

Fixup the kernel doc comment while at it.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250429065421.045492336@linutronix.de
2025-05-07 09:08:13 +02:00
Thomas Gleixner
15d772e2ee genirq/chip: Rework handle_eoi_irq()
Use the new helpers to decide whether the interrupt should be handled and
switch the descriptor locking to guard().

Fixup the kernel doc comment while at it.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250429065420.986002418@linutronix.de
2025-05-07 09:08:13 +02:00
Thomas Gleixner
2334c45521 genirq/chip: Rework handle_level_irq()
Use the new helpers to decide whether the interrupt should be handled and
switch the descriptor locking to guard().

Fixup the kernel doc comment while at it.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250429065420.926362488@linutronix.de
2025-05-07 09:08:13 +02:00
Thomas Gleixner
a155777175 genirq/chip: Rework handle_untracked_irq()
Use the new helpers to decide whether the interrupt should be handled and
switch the descriptor locking to guard().

Fixup the kernel doc comment while at it.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250429065420.865212916@linutronix.de
2025-05-07 09:08:12 +02:00
Thomas Gleixner
1a3678675f genirq/chip: Rework handle_simple_irq()
Use the new helpers to decide whether the interrupt should be handled and
switch the descriptor locking to guard().

Fixup the kernel doc comment while at it.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250429065420.804683349@linutronix.de
2025-05-07 09:08:12 +02:00
Thomas Gleixner
2ef2e13094 genirq/chip: Rework handle_nested_irq()
Use the new helpers to decide whether the interrupt should be handled and
switch the descriptor locking to guard().

Fixup the kernel doc comment while at it.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250429065420.744042890@linutronix.de
2025-05-07 09:08:12 +02:00
Thomas Gleixner
a6d8d0d12e genirq/chip: Prepare for code reduction
The interrupt flow handlers have similar patterns to decide whether to
handle an interrupt or not.

Provide common helper functions to allow removal of duplicated code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250429065420.682547546@linutronix.de
2025-05-07 09:08:12 +02:00
Linus Torvalds
7b667acd69 powerpc updates for 6.15
- Removal of support for IBM Cell Blades
 
  - SMP support for microwatt platform
 
  - Support for inline static calls on PPC32
 
  - Enable pmu selftests for power11 platform
 
  - Enable hardware trace macro (HTM) hcall support
 
  - Support for limited address mode capability
 
  - Changes to RMA size from 512 MB to 768 MB to handle fadump
 
  - Misc fixes and cleanups
 
 Thanks to: Abhishek Dubey, Amit Machhiwal, Andreas Schwab, Arnd Bergmann,
 Athira Rajeev, Avnish Chouhan, Christophe Leroy, Disha Goel, Donet Tom, Gaurav
 Batra, Gautam Menghani, Hari Bathini, Kajol Jain, Kees Cook, Mahesh Salgaonkar,
 Michael Ellerman, Paul Mackerras, Ritesh Harjani (IBM), Sathvika Vasireddy,
 Segher Boessenkool, Sourabh Jain, Vaibhav Jain, Venkat Rao Bagalkote.
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEEqX2DNAOgU8sBX3pRpnEsdPSHZJQFAmfjZnYACgkQpnEsdPSH
 ZJTmKg/+NGW7wyFY9d8Iai9ncYY7GSzsMSDTaan7qg0QWOd5gjHbsdbava7TM/DW
 8p9XsC+17kSeftRNUjtc52bSN8Ei2gBdsXIagQG1alfB2X2e6wkNauifK+dz3Su6
 usMEZZTO5R/jFDotFXNM1nsUj+8dvjnPgOUrji/P8k7PT5295wpza0hz1fy5SrOA
 hM5cliBP36UgFe5Efvgm4OUX2gQIhbc3stt9MVfymW/k0Mit5f41UIPuVGiTWowY
 s0cUJGkhxUlGXT3VfOVKuZfn4u9KMha7UCl9afSceJzXOdnUIKIbskui1VEv6cD/
 iSIxi839uErAobFHlsLYprgYFciYLII3xe2qNZCA/ZxeIMS/Mm6xokESeWLhBnfa
 P7ke6l0z3GDtTvgI2eSeU9BdrVveF1NgbP9GYSKgT6gtw/kRRnxgHF8tzmLON5PT
 KXpQlzz8VuSBRtF2jnLFU89+FFwSA1bRUhDrp89HyYFqw1B5g4N7kFFTUJWHOuKS
 fwPGy+cveKehmCUBedeTRFqHvvqdwpD/WnPlQzCly3WxqdL8U/eTXYftMiAwuK28
 ovLuSs3vRThKRQ8DnUa5oB0UGsjMpRV5LdvYkhw+x8mZKUR59oj4fx2ae4TtPakg
 dbAYuPPkCORdaSga/nV6vQgsLprFpcGX3dq6E19+BVBAY5D+1PE=
 =GFcj
 -----END PGP SIGNATURE-----

Merge tag 'powerpc-6.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Madhavan Srinivasan:

 - Remove support for IBM Cell Blades

 - SMP support for microwatt platform

 - Support for inline static calls on PPC32

 - Enable pmu selftests for power11 platform

 - Enable hardware trace macro (HTM) hcall support

 - Support for limited address mode capability

 - Changes to RMA size from 512 MB to 768 MB to handle fadump

 - Misc fixes and cleanups

Thanks to Abhishek Dubey, Amit Machhiwal, Andreas Schwab, Arnd Bergmann,
Athira Rajeev, Avnish Chouhan, Christophe Leroy, Disha Goel, Donet Tom,
Gaurav Batra, Gautam Menghani, Hari Bathini, Kajol Jain, Kees Cook,
Mahesh Salgaonkar, Michael Ellerman, Paul Mackerras, Ritesh Harjani
(IBM), Sathvika Vasireddy, Segher Boessenkool, Sourabh Jain, Vaibhav
Jain, and Venkat Rao Bagalkote.

* tag 'powerpc-6.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (61 commits)
  powerpc/kexec: fix physical address calculation in clear_utlb_entry()
  crypto: powerpc: Mark ghashp8-ppc.o as an OBJECT_FILES_NON_STANDARD
  powerpc: Fix 'intra_function_call not a direct call' warning
  powerpc/perf: Fix ref-counting on the PMU 'vpa_pmu'
  KVM: PPC: Enable CAP_SPAPR_TCE_VFIO on pSeries KVM guests
  powerpc/prom_init: Fixup missing #size-cells on PowerBook6,7
  powerpc/microwatt: Add SMP support
  powerpc: Define config option for processors with broadcast TLBIE
  powerpc/microwatt: Define an idle power-save function
  powerpc/microwatt: Device-tree updates
  powerpc/microwatt: Select COMMON_CLK in order to get the clock framework
  net: toshiba: Remove reference to PPC_IBM_CELL_BLADE
  net: spider_net: Remove powerpc Cell driver
  cpufreq: ppc_cbe: Remove powerpc Cell driver
  genirq: Remove IRQ_EDGE_EOI_HANDLER
  docs: Remove reference to removed CBE_CPUFREQ_SPU_GOVERNOR
  powerpc: Remove UDBG_RTAS_CONSOLE
  powerpc/io: Use standard barrier macros in io.c
  powerpc/io: Rename _insw_ns() etc.
  powerpc/io: Use generic raw accessors
  ...
2025-03-27 19:39:08 -07:00
Thomas Gleixner
827bafd527 genirq: Make a few functions static
None of these functions are used outside of their source files.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/878qpe2gnx.ffs@tglx
2025-03-10 10:01:20 +01:00
Michael Ellerman
333e8eb3e0 genirq: Remove IRQ_EDGE_EOI_HANDLER
The powerpc Cell blade support, now removed, was the only user of
IRQ_EDGE_EOI_HANDLER, so remove it.

Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20241218105523.416573-21-mpe@ellerman.id.au
2025-02-26 21:15:09 +05:30
Thomas Gleixner
f94a18249b genirq: Remove IRQ_MOVE_PCNTXT and related code
Now that x86 is converted over to use the IRQCHIP_MOVE_DEFERRED flags,
remove IRQ*_MOVE_PCNTXT and related code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20241210103335.626707225@linutronix.de
2025-01-15 21:38:53 +01:00
Thomas Gleixner
a648eb3a3f genirq: Provide IRQCHIP_MOVE_DEFERRED
The logic of GENERIC_PENDING_IRQ is backwards for historical reasons. Most
interrupt controllers allow to move the interrupt from arbitrary
contexts. If GENERIC_PENDING_IRQ is enabled by an architecture to support a
chip, which requires the affinity change to happen in interrupt context,
all other chips have to be marked with IRQF_MOVE_PCNTXT.

That's tedious and there is no real good reason for the extra flags in the
irq descriptor and the irq data status fields. In fact the decision whether
interrupts can be moved in arbitrary context or not is a property of the
interrupt chip.

To simplify adoption for RISC-V provide a new mechanism which is enabled
via a config switch and allows to add a flag to irq_chip::flags to request
that interrupt affinity changes are deferred. Setting the top level chip of
an interrupt evaluates the flag and maps it into the existing logic.

The config switch and the various PCNTXT flags are temporary until x86 is
converted over to this scheme. This intermediate step also allows trivial
backporting of the mechanism to plug the affinity change race of various
RISC-V interrupt controllers.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20241210103335.500314436@linutronix.de
2025-01-15 10:56:22 +01:00
Costa Shulyupin
a6fe30d1e3 genirq: Use cpumask_intersects()
Replace `cpumask_any_and(a, b) >= nr_cpu_ids` and `cpumask_any_and(a, b) <
nr_cpu_ids` with the more readable `!cpumask_intersects(a, b)` and
`cpumask_intersects(a, b)`

Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240906170142.1135207-1-costa.shul@redhat.com
2024-09-08 16:06:51 +02:00
Vincent Whitchurch
e2c12739cc genirq: Prevent nested thread vs synchronize_hardirq() deadlock
There is a possibility of deadlock if synchronize_hardirq() is called
when the nested threaded interrupt is active.  The following scenario
was observed on a uniprocessor PREEMPT_NONE system:

 Thread 1                      Thread 2

 handle_nested_thread()
  Set INPROGRESS
  Call ->thread_fn()
   thread_fn goes to sleep

                              free_irq()
                               __synchronize_hardirq()
                                Busy-loop forever waiting for INPROGRESS
                                to be cleared

The INPROGRESS flag is only supposed to be used for hard interrupt
handlers.  Remove the incorrect usage in the nested threaded interrupt
case and instead re-use the threads_active / wait_for_threads mechanism
to wait for nested threaded interrupts to complete.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230613-genirq-nested-v3-1-ae58221143eb@axis.com
2023-07-31 17:24:22 +02:00
Thomas Gleixner
f121ab7f4a irqchip updates for 6.5
- A number of Loogson/Loogarch fixes
 
 - Allow the core code to retrigger an interrupt that has
   fired while the same interrupt is being handled on another
   CPU, papering over a GICv3 architecture issue
 
 - Work around an integration problem on ASR8601, where the CPU
   numbering isn't representable in the GIC implementation...
 
 - Add some missing interrupt to the STM32 irqchip
 
 - A bunch of warning squashing triggered by W=1 builds
 -----BEGIN PGP SIGNATURE-----
 
 iQJDBAABCgAtFiEEn9UcU+C1Yxj9lZw9I9DQutE9ekMFAmSWHlEPHG1hekBrZXJu
 ZWwub3JnAAoJECPQ0LrRPXpDgDcP/AyuNjjt9ybZ8LT5hGYRBKTfO3bsssiV/ZIE
 NRbfwK6nWTurA3tN9XypYouB3HfKvTvDYHzeo9Yi2y51GI20o7noSfVNHHld5dAE
 WTBYcfc6n+1KqGNA1tPVeE403jd50TnmOmFaXhN1Vn/KQVQKs+LmjoVdS7HXKmwu
 PLk1tbFSGh5+vgLQTlhze5Wz7nU59lJ5WfCJ8negYls/5l3FseGgxEuffWKytElJ
 I6PbnRyd9y7R/KYmkobFjS98cjeNznAxJEm/2InVpcb3IwUSEyJUHgNwbs6KSeYf
 4BdVyxSAQlFPgxO17UKQxblYu/HuFY/NWghkg7dn6ZgVubj52rtrl9txUId57HGC
 pYbSVm0bMevqlgHDYHold+Q4I6DqltyHKgiA9UfU9IQj4MV/KXbDjtng/ih4ZkHe
 rw+BnckyrhZ5K5p3nDlzS/TNQT1baKqNFgx/O5HPV27NT8ARynqoFxNUzA0z37v3
 x5dj34kiIW2kAGJDOP9+9jj2uF4yX0MKdNxdMs8PM9hYAsO0AqItNsXEQoUuzJF+
 u1hhGZ1H6HYmY2WphXD57fnIR/7Hm6Iz00XC17+1jUP+wsefhAbreOyJIbbcpENF
 IIxrcIxAPl3PQPsj8n98/9fKQ6u/QfrvWUH+6aoFQH/Np7RTFWmDh8bqucjuXsGS
 8gxR3REr
 =quHC
 -----END PGP SIGNATURE-----

Merge tag 'irqchip-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms into irq/core

Pull irqchip updates from Marc Zyngier:

  - A number of Loogson/Loogarch fixes

  - Allow the core code to retrigger an interrupt that has
    fired while the same interrupt is being handled on another
    CPU, papering over a GICv3 architecture issue

  - Work around an integration problem on ASR8601, where the CPU
    numbering isn't representable in the GIC implementation...

  - Add some missing interrupt to the STM32 irqchip

  - A bunch of warning squashing triggered by W=1 builds

Link: https://lore.kernel.org/r/20230623224345.3577134-1-maz@kernel.org
2023-06-26 11:05:49 +02:00
James Gowans
9c15eeb536 genirq: Allow fasteoi handler to resend interrupts on concurrent handling
There is a class of interrupt controllers out there that, once they
have signalled a given interrupt number, will still signal incoming
instances of the *same* interrupt despite the original interrupt
not having been EOIed yet.

As long as the new interrupt reaches the *same* CPU, nothing bad
happens, as that CPU still has its interrupts globally disabled,
and we will only take the new interrupt once the interrupt has
been EOIed.

However, things become more "interesting" if an affinity change comes
in while the interrupt is being handled. More specifically, while
the per-irq lock is being dropped. This results in the affinity change
taking place immediately. At this point, there is nothing that prevents
the interrupt from firing on the new target CPU. We end-up with the
interrupt running concurrently on two CPUs, which isn't a good thing.

And that's where things become worse: the new CPU notices that the
interrupt handling is in progress (irq_may_run() return false), and
*drops the interrupt on the floor*.

The whole race looks like this:

           CPU 0             |          CPU 1
-----------------------------|-----------------------------
interrupt start              |
  handle_fasteoi_irq         | set_affinity(CPU 1)
    handler                  |
    ...                      | interrupt start
    ...                      |   handle_fasteoi_irq -> early out
  handle_fasteoi_irq return  | interrupt end
interrupt end                |

If the interrupt was an edge, too bad. The interrupt is lost, and
the system will eventually die one way or another. Not great.

A way to avoid this situation is to detect this problem at the point
we handle the interrupt on the new target. Instead of dropping the
interrupt, use the resend mechanism to force it to be replayed.

Also, in order to limit the impact of this workaround to the pathetic
architectures that require it, gate it behind a new irq flag aptly
named IRQD_RESEND_WHEN_IN_PROGRESS.

Suggested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: James Gowans <jgowans@amazon.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <maz@kernel.org>
Cc: KarimAllah Raslan <karahmed@amazon.com>
Cc: Yipeng Zou <zouyipeng@huawei.com>
Cc: Zhang Jianhua <chris.zjh@huawei.com>
[maz: reworded commit mesage]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230608120021.3273400-3-jgowans@amazon.com
2023-06-16 12:22:35 +01:00
Shanker Donthineni
bc06a9e087 genirq: Use hlist for managing resend handlers
The current implementation utilizes a bitmap for managing interrupt resend
handlers, which is allocated based on the SPARSE_IRQ/NR_IRQS macros.
However, this method may not efficiently utilize memory during runtime,
particularly when IRQ_BITMAP_BITS is large.

Address this issue by using an hlist to manage interrupt resend handlers
instead of relying on a static bitmap memory allocation. Additionally, a
new function, clear_irq_resend(), is introduced and called from
irq_shutdown to ensure a graceful teardown of the interrupt.

Signed-off-by: Shanker Donthineni <sdonthineni@nvidia.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230519134902.1495562-2-sdonthineni@nvidia.com
2023-05-24 11:39:44 +02:00
Thomas Gleixner
6a9fc4190c genirq/irqdomain: Rename irq_domain::dev to irq_domain:: Pm_dev
irq_domain::dev is a misnomer as it's usually the rule that a device
pointer points to something which is directly related to the instance.

irq_domain::dev can point to some other device for power management to
ensure that this underlying device is not powered down when an interrupt is
allocated.

The upcoming per device MSI domains really require a pointer to the device
which instantiated the irq domain and not to some random other device which
is required for power management down the chain.

Rename irq_domain::dev to irq_domain::pm_dev and fixup the few sites which
use that pointer.

Conversion was done with the help of coccinelle.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221124230313.574541683@linutronix.de
2022-12-05 19:20:58 +01:00
Marc Zyngier
d4a930a08c Merge branch irq/plic-masking into irq/irqchip-next
* irq/plic-masking:
  : .
  : SiFive PLIC optimisations from Samuel Holland:
  :
  : "This series removes the spinlocks and cpumask operations from the PLIC
  : driver's hot path. As far as I know, using the priority to mask
  : interrupts is an intended usage and will work on all existing
  : implementations. [...]"
  : .
  irqchip/sifive-plic: Separate the enable and mask operations
  irqchip/sifive-plic: Make better use of the effective affinity mask
  PCI: hv: Take a const cpumask in hv_compose_msi_req_get_cpu()
  genirq: Provide an IRQ affinity mask in non-SMP configs
  genirq: Return a const cpumask from irq_data_get_affinity_mask
  genirq: Add and use an irq_data_update_affinity helper
  genirq: Refactor accessors to use irq_data_get_affinity_mask
  genirq: Drop redundant irq_init_effective_affinity
  genirq: GENERIC_IRQ_EFFECTIVE_AFF_MASK depends on SMP
  genirq: GENERIC_IRQ_IPI depends on SMP
  irqchip/mips-gic: Only register IPI domain when SMP is enabled

Signed-off-by: Marc Zyngier <maz@kernel.org>
2022-07-10 09:51:20 +01:00
Samuel Holland
4d0b829881 genirq: Return a const cpumask from irq_data_get_affinity_mask
Now that the irq_data_update_affinity helper exists, enforce its use
by returning a a const cpumask from irq_data_get_affinity_mask.

Since the previous commit already updated places that needed to call
irq_data_update_affinity, this commit updates the remaining code that
either did not modify the cpumask or immediately passed the modified
mask to irq_set_affinity.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220701200056.46555-8-samuel@sholland.org
2022-07-07 09:38:04 +01:00
Antonio Borneo
95001b7564 genirq: Don't return error on missing optional irq_request_resources()
Function irq_chip::irq_request_resources() is reported as optional
in the declaration of struct irq_chip.
If the parent irq_chip does not implement it, we should ignore it
and return.

Don't return error if the functions is missing.

Signed-off-by: Antonio Borneo <antonio.borneo@foss.st.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220512160544.13561-1-antonio.borneo@foss.st.com
2022-07-07 09:04:13 +01:00
Marc Zyngier
668a9fe5c6 genirq: PM: Use runtime PM for chained interrupts
When requesting an interrupt, we correctly call into the runtime
PM framework to guarantee that the underlying interrupt controller
is up and running.

However, we fail to do so for chained interrupt controllers, as
the mux interrupt is not requested along the same path.

Augment __irq_do_set_handler() to call into the runtime PM code
in this case, making sure the PM flow is the same for all interrupts.

Reported-by: Lucas Stach <l.stach@pengutronix.de>
Tested-by: Liu Ying <victor.liu@nxp.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/26973cddee5f527ea17184c0f3fccb70bc8969a0.camel@pengutronix.de
2022-06-09 15:58:13 +01:00
Minghao Chi
ce4818957f genirq: Use pm_runtime_resume_and_get() instead of pm_runtime_get_sync()
pm_runtime_resume_and_get() achieves the same and simplifies the code.

[ tglx: Simplify it further by presetting retval ]

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Minghao Chi <chi.minghao@zte.com.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220418110716.2559453-1-chi.minghao@zte.com.cn
2022-05-02 14:08:08 +02:00
Marc Zyngier
393e1280f7 genirq: Allow irq_chip registration functions to take a const irq_chip
In order to let a const irqchip be fed to the irqchip layer, adjust
the various prototypes. An extra cast in irq_set_chip()() is required
to avoid a warning.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20220209162607.1118325-3-maz@kernel.org
2022-02-15 11:10:21 +00:00
Marc Zyngier
beb0622138 genirq: Kill irq_chip::parent_device
Now that noone is using irq_chip::parent_device in the tree, get
rid of it.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Bartosz Golaszewski <brgl@bgdev.pl>
Link: https://lore.kernel.org/r/20220201120310.878267-13-maz@kernel.org
2022-02-10 11:07:04 +00:00
Marc Zyngier
1f8863bfb5 genirq: Allow the PM device to originate from irq domain
As a preparation to moving the reference to the device used for
runtime power management, add a new 'dev' field to the irqdomain
structure for that exact purpose.

The irq_chip_pm_{get,put}() helpers are made aware of the dual
location via a new private helper.

No functional change intended.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Tony Lindgren <tony@atomide.com>
Acked-by: Bartosz Golaszewski <brgl@bgdev.pl>
Link: https://lore.kernel.org/r/20220201120310.878267-2-maz@kernel.org
2022-02-09 13:35:56 +00:00
Sebastian Andrzej Siewior
5320eb42de irq: remove unused flags argument from __handle_irq_event_percpu()
The __IRQF_TIMER bit from the flags argument was used in
add_interrupt_randomness() to distinguish the timer interrupt from other
interrupts. This is no longer the case.

Remove the flags argument from __handle_irq_event_percpu().

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-01-07 00:25:25 +01:00
Marc Zyngier
8d15a7295d genirq: Hide irq_cpu_{on,off}line() behind a deprecated option
irq_cpu_{on,off}line() are now only used by the Octeon platform.
Make their use conditional on this plaform being enabled, and
otherwise hidden away.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Serge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20211021170414.3341522-4-maz@kernel.org
2021-10-26 11:19:55 +01:00
Thomas Gleixner
826da77129 genirq: Provide IRQCHIP_AFFINITY_PRE_STARTUP
X86 IO/APIC and MSI interrupts (when used without interrupts remapping)
require that the affinity setup on startup is done before the interrupt is
enabled for the first time as the non-remapped operation mode cannot safely
migrate enabled interrupts from arbitrary contexts. Provide a new irq chip
flag which allows affected hardware to request this.

This has to be opt-in because there have been reports in the past that some
interrupt chips cannot handle affinity setting before startup.

Fixes: 1840475676 ("genirq: Expose default irq affinity mask (take 3)")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210729222542.779791738@linutronix.de
2021-08-10 10:59:20 +02:00
Thomas Gleixner
c2b1063e8f genirq: Add a IRQF_NO_DEBUG flag
The whole call to note_interrupt() can be avoided or return early when
interrupts would be marked accordingly. For IPI handlers which always
return HANDLED the whole procedure is pretty pointless to begin with.

Add a IRQF_NO_DEBUG flag and mark the interrupt accordingly if supplied
when the interrupt is requested.

When noirqdebug is set on the kernel commandline, then the interrupt is
marked unconditionally so that there is only one condition in the hotpath
to evaluate.

 [ clg: Add changelog ]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/7a8ad02f-63a8-c1aa-fdd1-39d973593d02@kaod.org
2021-05-17 20:01:35 +02:00
Ingo Molnar
a359f75796 irq: Fix typos in comments
Fix ~36 single-word typos in the IRQ, irqchip and irqdomain code comments.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-03-22 04:23:14 +01:00
Krzysztof Kozlowski
5c982c5875 genirq: Fix typos and misspellings in comments
No functional change.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210316100205.23492-1-krzysztof.kozlowski@canonical.com
2021-03-16 15:08:29 +01:00
Thomas Gleixner
3c41e57a1e irqchip updates for Linux 5.11
- Preliminary support for managed interrupts on platform devices
 - Correctly identify allocation of MSIs proxyied by another device
 - Remove the fasteoi IPI flow which has been proved useless
 - Generalise the Ocelot support to new SoCs
 - Improve GICv4.1 vcpu entry, matching the corresponding KVM optimisation
 - Work around spurious interrupts on Qualcomm PDC
 - Random fixes and cleanups
 -----BEGIN PGP SIGNATURE-----
 
 iQJDBAABCgAtFiEEn9UcU+C1Yxj9lZw9I9DQutE9ekMFAl/Uxq8PHG1hekBrZXJu
 ZWwub3JnAAoJECPQ0LrRPXpDoW0P/0ZMDvFPxrfnJD46exUgUOPuuFF8jZxAlxD8
 7UExqar7u6yX7bbq394jPgtOOxldDagfCx/jCXgb9ja7DK5EHKRcrfjaDT8knHi2
 Keg5RaRMRi9TVltvWQTxAkXwSv0Atl881qqsndPeZCez0GNZp+HB34s+rNkZwBOu
 MBrWihMQOSv5QE6milsNc7HXLSHM1eLZ7Y2XgumNtKrIGEX9yZI7qwdMofwP8Za3
 ayMOvc1WAWaTJI7Mg5ac1yTCVbqLmRHhCtws6c6DMgaRu6SI0itmbpQzkDuJJIe3
 k9h4KQPaKAFcQsoo3GV0MKTMm63eq82XT3CAdv+htYRY1z95D2+nzNK+mJtsGptX
 gJ2zeJkUb4u+yVtNguL9qjo5ssCXV/6IybJxv6baaEFnSwQMUwqa066NdxmtqfIe
 1BOWnc153a7SRbQ34M9/llje+v8YJbueGMS2RFR2LQ6IjjpaHsXh+YCZokfA/kdk
 zGbOUD5WWFtFD1T3UoaJ4gFt+pzHjNqym4CcEj4S1Vf5y+POUkNmC+GYK+xfm2Fp
 WJMbdIUxJhHFRD9L1ShtfAVUSbp712VOOdILp9rYAkOdqfb51BVUiMUP++s2dGp1
 ZIT78qt7kTKT1CxbDdFAjzsi7RoMqdSGYgKmG4sVprELeZnFwq47nBkBr8XEQ1TT
 0ccEUOY8
 =7Z24
 -----END PGP SIGNATURE-----

Merge tag 'irqchip-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms into irq/core

Pull irqchip updates for 5.11 from Marc Zyngier:

  - Preliminary support for managed interrupts on platform devices
  - Correctly identify allocation of MSIs proxyied by another device
  - Remove the fasteoi IPI flow which has been proved useless
  - Generalise the Ocelot support to new SoCs
  - Improve GICv4.1 vcpu entry, matching the corresponding KVM optimisation
  - Work around spurious interrupts on Qualcomm PDC
  - Random fixes and cleanups

Link: https://lore.kernel.org/r/20201212135626.1479884-1-maz@kernel.org
2020-12-15 10:48:07 +01:00
Valentin Schneider
b388fa5014 Revert "genirq: Add fasteoi IPI flow"
handle_percpu_devid_fasteoi_ipi() has no more users, and
handle_percpu_devid_irq() can do all that it was supposed to do. Get rid of
it.

This reverts commit c5e5ec033c.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201109094121.29975-6-valentin.schneider@arm.com
2020-12-11 14:47:50 +00:00
Mauro Carvalho Chehab
8c67d247dc genirq: Fix kernel-doc markups
Some identifiers have different names between their prototypes
and the kernel-doc markup.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/13a44f4f0c3135e14b16ae8fcce4af1eab27cb5f.1605521731.git.mchehab+huawei@kernel.org
2020-11-16 15:20:54 +01:00
Linus Torvalds
cc7343724e Surgery of the MSI interrupt handling to prepare the support of upcoming
devices which require non-PCI based MSI handling.
 
   - Cleanup historical leftovers all over the place
 
   - Rework the code to utilize more core functionality
 
   - Wrap XEN PCI/MSI interrupts into an irqdomain to make irqdomain
     assignment to PCI devices possible.
 
   - Assign irqdomains to PCI devices at initialization time which allows
     to utilize the full functionality of hierarchical irqdomains.
 
   - Remove arch_.*_msi_irq() functions from X86 and utilize the irqdomain
     which is assigned to the device for interrupt management.
 
   - Make the arch_.*_msi_irq() support conditional on a config switch and
     let the last few users select it.
 -----BEGIN PGP SIGNATURE-----
 
 iQJHBAABCgAxFiEEQp8+kY+LLUocC4bMphj1TA10mKEFAl+EUxcTHHRnbHhAbGlu
 dXRyb25peC5kZQAKCRCmGPVMDXSYoagLEACGp5U7a4mk24GsOZJDhrua1PHR/fhb
 enn/5yOPpxDXdYmtFHIjV5qrNjDTV/WqDlI96KOi+oinG1Eoj0O/MA1AcSRhp6nf
 jVdAuK1X0DHDUTEeTAP0JFwqd2j0KlIOphBrIMgeWIf1CRKlYiJaO+ioF9fKgwZ/
 /HigOTSykGYMPggm3JXnWTWtJkKSGFxeADBvVHt5RpVmbWtrI4YoSBxKEMtvjyeM
 5+GsqbCad1CnFYTN74N+QWVGmgGnUWGEzWsPYnJ9hW+yyjad1kWx3n6NcCWhssaC
 E4vAXl6JuCPntL7jBFkbfUkQsgq12ThMZYWpCq8pShJA9O2tDKkxIGasHWrIt4cz
 nYrESiv6hM7edjtOvBc086Gd0A2EyGOM879goHyaNVaTO4rI6jfZG7PlW1HHWibS
 mf/bdTXBtULGNgEt7T8Qnb8sZ+D01WqzLrq/wm645jIrTzvNHUEpOhT1aH/g4TFQ
 cNHD5PcM9OTmiBir9srNd47+1s2mpfwdMYHKBt2QgiXMO8fRgdtr6WLQE4vJjmG8
 sA0yGGsgdTKeg2wW1ERF1pWL0Lt05Iaa42Skm0D3BwcOG2n5ltkBHzVllto9cTUh
 kIldAOgxGE6QeCnnlrnbHz5mvzt/3Ih/PIKqPSUAC94Kx1yvVHRYuOvDExeO8DFB
 P+f0TkrscZObSg==
 =JlqV
 -----END PGP SIGNATURE-----

Merge tag 'x86-irq-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 irq updates from Thomas Gleixner:
 "Surgery of the MSI interrupt handling to prepare the support of
  upcoming devices which require non-PCI based MSI handling:

   - Cleanup historical leftovers all over the place

   - Rework the code to utilize more core functionality

   - Wrap XEN PCI/MSI interrupts into an irqdomain to make irqdomain
     assignment to PCI devices possible.

   - Assign irqdomains to PCI devices at initialization time which
     allows to utilize the full functionality of hierarchical
     irqdomains.

   - Remove arch_.*_msi_irq() functions from X86 and utilize the
     irqdomain which is assigned to the device for interrupt management.

   - Make the arch_.*_msi_irq() support conditional on a config switch
     and let the last few users select it"

* tag 'x86-irq-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (40 commits)
  PCI: MSI: Fix Kconfig dependencies for PCI_MSI_ARCH_FALLBACKS
  x86/apic/msi: Unbreak DMAR and HPET MSI
  iommu/amd: Remove domain search for PCI/MSI
  iommu/vt-d: Remove domain search for PCI/MSI[X]
  x86/irq: Make most MSI ops XEN private
  x86/irq: Cleanup the arch_*_msi_irqs() leftovers
  PCI/MSI: Make arch_.*_msi_irq[s] fallbacks selectable
  x86/pci: Set default irq domain in pcibios_add_device()
  iommm/amd: Store irq domain in struct device
  iommm/vt-d: Store irq domain in struct device
  x86/xen: Wrap XEN MSI management into irqdomain
  irqdomain/msi: Allow to override msi_domain_alloc/free_irqs()
  x86/xen: Consolidate XEN-MSI init
  x86/xen: Rework MSI teardown
  x86/xen: Make xen_msi_init() static and rename it to xen_hvm_msi_init()
  PCI/MSI: Provide pci_dev_has_special_msi_domain() helper
  PCI_vmd_Mark_VMD_irqdomain_with_DOMAIN_BUS_VMD_MSI
  irqdomain/msi: Provide DOMAIN_BUS_VMD_MSI
  x86/irq: Initialize PCI/MSI domain at PCI init time
  x86/pci: Reducde #ifdeffery in PCI init code
  ...
2020-10-12 11:40:41 -07:00
Thomas Gleixner
13b90cadfc genirq/chip: Use the first chip in irq_chip_compose_msi_msg()
The documentation of irq_chip_compose_msi_msg() claims that with
hierarchical irq domains the first chip in the hierarchy which has an
irq_compose_msi_msg() callback is chosen. But the code just keeps
iterating after it finds a chip with a compose callback.

The x86 HPET MSI implementation relies on that behaviour, but that does not
make it more correct.

The message should always be composed at the domain which manages the
underlying resource (e.g. APIC or remap table) because that domain knows
about the required layout of the message.

On X86 the following hierarchies exist:

1)   vector -------- PCI/MSI
2)   vector -- IR -- PCI/MSI

The vector domain has a different message format than the IR (remapping)
domain. So obviously the PCI/MSI domain can't compose the message without
having knowledge about the parent domain, which is exactly the opposite of
what hierarchical domains want to achieve.

X86 actually has two different PCI/MSI chips where #1 has a compose
callback and #2 does not. #2 delegates the composition to the remap domain
where it belongs, but #1 does it at the PCI/MSI level.

For the upcoming device MSI support it's necessary to change this and just
let the first domain which can compose the message take care of it. That
way the top level chip does not have to worry about it and the device MSI
code does not need special knowledge about topologies. It just sets the
compose callback to NULL and lets the hierarchy pick the first chip which
has one.

Due to that the attempt to move the compose callback from the direct
delivery PCI/MSI domain to the vector domain made the system fail to boot
with interrupt remapping enabled because in the remapping case
irq_chip_compose_msi_msg() keeps iterating and choses the compose callback
of the vector domain which obviously creates the wrong format for the remap
table.

Break out of the loop when the first irq chip with a compose callback is
found and fixup the HPET code temporarily. That workaround will be removed
once the direct delivery compose callback is moved to the place where it
belongs in the vector domain.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Marc Zyngier <maz@kernel.org>                                                                                                                                                                                                                                     Link: https://lore.kernel.org/r/20200826112331.047917603@linutronix.de
2020-09-16 16:52:28 +02:00