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| author | Marc Zyngier <marc.zyngier@arm.com> | 2014-08-26 11:03:16 +0100 |
|---|---|---|
| committer | Jason Cooper <jason@lakedaemon.net> | 2014-09-03 12:57:27 +0000 |
| commit | 76ba59f8366f2d9282cb5bda9de75b4b68cbe55f (patch) | |
| tree | 567c5a7b10fb8f7a1e597a8cc83c0afe92dbce50 /kernel/irq/Kconfig | |
| parent | 7d1311b93e58ed55f3a31cc8f94c4b8fe988a2b9 (diff) | |
| download | lwn-76ba59f8366f2d9282cb5bda9de75b4b68cbe55f.tar.gz lwn-76ba59f8366f2d9282cb5bda9de75b4b68cbe55f.zip | |
genirq: Add irq_domain-aware core IRQ handler
Calling irq_find_mapping from outside a irq_{enter,exit} section is
unsafe and produces ugly messages if CONFIG_PROVE_RCU is enabled:
If coming from the idle state, the rcu_read_lock call in irq_find_mapping
will generate an unpleasant warning:
<quote>
===============================
[ INFO: suspicious RCU usage. ]
3.16.0-rc1+ #135 Not tainted
-------------------------------
include/linux/rcupdate.h:871 rcu_read_lock() used illegally while idle!
other info that might help us debug this:
RCU used illegally from idle CPU!
rcu_scheduler_active = 1, debug_locks = 0
RCU used illegally from extended quiescent state!
1 lock held by swapper/0/0:
#0: (rcu_read_lock){......}, at: [<ffffffc00010206c>]
irq_find_mapping+0x4c/0x198
</quote>
As this issue is fairly widespread and involves at least three
different architectures, a possible solution is to add a new
handle_domain_irq entry point into the generic IRQ code that
the interrupt controller code can call.
This new function takes an irq_domain, and calls into irq_find_domain
inside the irq_{enter,exit} block. An additional "lookup" parameter is
used to allow non-domain architecture code to be replaced by this as well.
Interrupt controllers can then be updated to use the new mechanism.
This code is sitting behind a new CONFIG_HANDLE_DOMAIN_IRQ, as not all
architectures implement set_irq_regs (yes, mn10300, I'm looking at you...).
Reported-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Link: https://lkml.kernel.org/r/1409047421-27649-2-git-send-email-marc.zyngier@arm.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Diffstat (limited to 'kernel/irq/Kconfig')
| -rw-r--r-- | kernel/irq/Kconfig | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig index d269cecdfbf0..225086b2652e 100644 --- a/kernel/irq/Kconfig +++ b/kernel/irq/Kconfig @@ -55,6 +55,9 @@ config GENERIC_IRQ_CHIP config IRQ_DOMAIN bool +config HANDLE_DOMAIN_IRQ + bool + config IRQ_DOMAIN_DEBUG bool "Expose hardware/virtual IRQ mapping via debugfs" depends on IRQ_DOMAIN && DEBUG_FS |