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genirq: Add irq_domain-aware core IRQ handler

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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>
This commit is contained in:
Marc Zyngier 2014-08-26 11:03:16 +01:00 • committed by Jason Cooper
parent 7d1311b93e
commit 76ba59f836
3 changed files with 64 additions and 0 deletions
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19
include/linux/irqdesc.h
View file

@ -12,6 +12,8 @@ struct irq_affinity_notify;
struct proc_dir_entry;
struct module;
struct irq_desc;
struct irq_domain;
struct pt_regs;
/**
* struct irq_desc - interrupt descriptor
@ -118,6 +120,23 @@ static inline void generic_handle_irq_desc(unsigned int irq, struct irq_desc *de
int generic_handle_irq(unsigned int irq);
#ifdef CONFIG_HANDLE_DOMAIN_IRQ
/*
* Convert a HW interrupt number to a logical one using a IRQ domain,
* and handle the result interrupt number. Return -EINVAL if
* conversion failed. Providing a NULL domain indicates that the
* conversion has already been done.
*/
int __handle_domain_irq(struct irq_domain *domain, unsigned int hwirq,
bool lookup, struct pt_regs *regs);
static inline int handle_domain_irq(struct irq_domain *domain,
unsigned int hwirq, struct pt_regs *regs)
{
return __handle_domain_irq(domain, hwirq, true, regs);
}
#endif
/* Test to see if a driver has successfully requested an irq */
static inline int irq_has_action(unsigned int irq)
{