![Benjamin Herrenschmidt](/assets/img/avatar_default.png)
Some architectures, like powerpc, implement lazy disabling of interrupts. That means that on those, local_irq_disable() doesn't actually disable interrupts on the CPU, but only sets some per CPU flag which cause them to be disabled only if an interrupt actually occurs. However, in some cases, such as stop_machine, we really want interrupts to be fully disabled. For example, I have code using stop machine to do ECC error injection, used to verify operations of the ECC hardware, that sort of thing. It really needs to make sure that nothing is actually writing to memory while the injection happens. Similar examples can be found in other low level bits and pieces. This patch implements a generic hard_irq_disable() function which is meant to be called -after- local_irq_disable() and ensures that interrupts are fully disabled on that CPU. The default implementation is a nop, though powerpc does already provide an appropriate one. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
460 lines
13 KiB
C
460 lines
13 KiB
C
/* interrupt.h */
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#ifndef _LINUX_INTERRUPT_H
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#define _LINUX_INTERRUPT_H
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#include <linux/kernel.h>
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#include <linux/linkage.h>
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#include <linux/bitops.h>
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#include <linux/preempt.h>
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#include <linux/cpumask.h>
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#include <linux/irqreturn.h>
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#include <linux/hardirq.h>
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#include <linux/sched.h>
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#include <linux/irqflags.h>
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#include <linux/bottom_half.h>
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#include <linux/device.h>
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#include <asm/atomic.h>
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#include <asm/ptrace.h>
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#include <asm/system.h>
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/*
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* These correspond to the IORESOURCE_IRQ_* defines in
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* linux/ioport.h to select the interrupt line behaviour. When
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* requesting an interrupt without specifying a IRQF_TRIGGER, the
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* setting should be assumed to be "as already configured", which
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* may be as per machine or firmware initialisation.
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*/
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#define IRQF_TRIGGER_NONE 0x00000000
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#define IRQF_TRIGGER_RISING 0x00000001
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#define IRQF_TRIGGER_FALLING 0x00000002
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#define IRQF_TRIGGER_HIGH 0x00000004
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#define IRQF_TRIGGER_LOW 0x00000008
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#define IRQF_TRIGGER_MASK (IRQF_TRIGGER_HIGH | IRQF_TRIGGER_LOW | \
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IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING)
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#define IRQF_TRIGGER_PROBE 0x00000010
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/*
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* These flags used only by the kernel as part of the
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* irq handling routines.
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*
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* IRQF_DISABLED - keep irqs disabled when calling the action handler
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* IRQF_SAMPLE_RANDOM - irq is used to feed the random generator
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* IRQF_SHARED - allow sharing the irq among several devices
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* IRQF_PROBE_SHARED - set by callers when they expect sharing mismatches to occur
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* IRQF_TIMER - Flag to mark this interrupt as timer interrupt
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* IRQF_PERCPU - Interrupt is per cpu
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* IRQF_NOBALANCING - Flag to exclude this interrupt from irq balancing
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* IRQF_IRQPOLL - Interrupt is used for polling (only the interrupt that is
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* registered first in an shared interrupt is considered for
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* performance reasons)
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*/
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#define IRQF_DISABLED 0x00000020
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#define IRQF_SAMPLE_RANDOM 0x00000040
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#define IRQF_SHARED 0x00000080
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#define IRQF_PROBE_SHARED 0x00000100
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#define IRQF_TIMER 0x00000200
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#define IRQF_PERCPU 0x00000400
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#define IRQF_NOBALANCING 0x00000800
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#define IRQF_IRQPOLL 0x00001000
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/*
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* Migration helpers. Scheduled for removal in 9/2007
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* Do not use for new code !
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*/
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static inline
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unsigned long __deprecated deprecated_irq_flag(unsigned long flag)
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{
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return flag;
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}
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#define SA_INTERRUPT deprecated_irq_flag(IRQF_DISABLED)
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#define SA_SAMPLE_RANDOM deprecated_irq_flag(IRQF_SAMPLE_RANDOM)
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#define SA_SHIRQ deprecated_irq_flag(IRQF_SHARED)
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#define SA_PROBEIRQ deprecated_irq_flag(IRQF_PROBE_SHARED)
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#define SA_PERCPU deprecated_irq_flag(IRQF_PERCPU)
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#define SA_TRIGGER_LOW deprecated_irq_flag(IRQF_TRIGGER_LOW)
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#define SA_TRIGGER_HIGH deprecated_irq_flag(IRQF_TRIGGER_HIGH)
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#define SA_TRIGGER_FALLING deprecated_irq_flag(IRQF_TRIGGER_FALLING)
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#define SA_TRIGGER_RISING deprecated_irq_flag(IRQF_TRIGGER_RISING)
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#define SA_TRIGGER_MASK deprecated_irq_flag(IRQF_TRIGGER_MASK)
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typedef irqreturn_t (*irq_handler_t)(int, void *);
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struct irqaction {
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irq_handler_t handler;
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unsigned long flags;
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cpumask_t mask;
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const char *name;
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void *dev_id;
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struct irqaction *next;
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int irq;
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struct proc_dir_entry *dir;
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};
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extern irqreturn_t no_action(int cpl, void *dev_id);
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extern int __must_check request_irq(unsigned int, irq_handler_t handler,
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unsigned long, const char *, void *);
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extern void free_irq(unsigned int, void *);
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extern int __must_check devm_request_irq(struct device *dev, unsigned int irq,
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irq_handler_t handler, unsigned long irqflags,
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const char *devname, void *dev_id);
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extern void devm_free_irq(struct device *dev, unsigned int irq, void *dev_id);
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/*
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* On lockdep we dont want to enable hardirqs in hardirq
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* context. Use local_irq_enable_in_hardirq() to annotate
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* kernel code that has to do this nevertheless (pretty much
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* the only valid case is for old/broken hardware that is
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* insanely slow).
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*
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* NOTE: in theory this might break fragile code that relies
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* on hardirq delivery - in practice we dont seem to have such
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* places left. So the only effect should be slightly increased
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* irqs-off latencies.
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*/
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#ifdef CONFIG_LOCKDEP
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# define local_irq_enable_in_hardirq() do { } while (0)
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#else
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# define local_irq_enable_in_hardirq() local_irq_enable()
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#endif
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#ifdef CONFIG_GENERIC_HARDIRQS
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extern void disable_irq_nosync(unsigned int irq);
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extern void disable_irq(unsigned int irq);
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extern void enable_irq(unsigned int irq);
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/*
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* Special lockdep variants of irq disabling/enabling.
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* These should be used for locking constructs that
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* know that a particular irq context which is disabled,
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* and which is the only irq-context user of a lock,
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* that it's safe to take the lock in the irq-disabled
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* section without disabling hardirqs.
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*
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* On !CONFIG_LOCKDEP they are equivalent to the normal
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* irq disable/enable methods.
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*/
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static inline void disable_irq_nosync_lockdep(unsigned int irq)
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{
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disable_irq_nosync(irq);
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#ifdef CONFIG_LOCKDEP
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local_irq_disable();
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#endif
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}
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static inline void disable_irq_nosync_lockdep_irqsave(unsigned int irq, unsigned long *flags)
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{
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disable_irq_nosync(irq);
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#ifdef CONFIG_LOCKDEP
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local_irq_save(*flags);
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#endif
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}
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static inline void disable_irq_lockdep(unsigned int irq)
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{
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disable_irq(irq);
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#ifdef CONFIG_LOCKDEP
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local_irq_disable();
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#endif
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}
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static inline void enable_irq_lockdep(unsigned int irq)
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{
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#ifdef CONFIG_LOCKDEP
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local_irq_enable();
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#endif
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enable_irq(irq);
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}
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static inline void enable_irq_lockdep_irqrestore(unsigned int irq, unsigned long *flags)
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{
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#ifdef CONFIG_LOCKDEP
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local_irq_restore(*flags);
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#endif
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enable_irq(irq);
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}
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/* IRQ wakeup (PM) control: */
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extern int set_irq_wake(unsigned int irq, unsigned int on);
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static inline int enable_irq_wake(unsigned int irq)
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{
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return set_irq_wake(irq, 1);
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}
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static inline int disable_irq_wake(unsigned int irq)
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{
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return set_irq_wake(irq, 0);
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}
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#else /* !CONFIG_GENERIC_HARDIRQS */
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/*
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* NOTE: non-genirq architectures, if they want to support the lock
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* validator need to define the methods below in their asm/irq.h
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* files, under an #ifdef CONFIG_LOCKDEP section.
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*/
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#ifndef CONFIG_LOCKDEP
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# define disable_irq_nosync_lockdep(irq) disable_irq_nosync(irq)
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# define disable_irq_nosync_lockdep_irqsave(irq, flags) \
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disable_irq_nosync(irq)
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# define disable_irq_lockdep(irq) disable_irq(irq)
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# define enable_irq_lockdep(irq) enable_irq(irq)
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# define enable_irq_lockdep_irqrestore(irq, flags) \
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enable_irq(irq)
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# endif
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#endif /* CONFIG_GENERIC_HARDIRQS */
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#ifndef __ARCH_SET_SOFTIRQ_PENDING
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#define set_softirq_pending(x) (local_softirq_pending() = (x))
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#define or_softirq_pending(x) (local_softirq_pending() |= (x))
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#endif
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/*
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* Temporary defines for UP kernels, until all code gets fixed.
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*/
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#ifndef CONFIG_SMP
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static inline void __deprecated cli(void)
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{
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local_irq_disable();
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}
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static inline void __deprecated sti(void)
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{
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local_irq_enable();
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}
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static inline void __deprecated save_flags(unsigned long *x)
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{
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local_save_flags(*x);
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}
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#define save_flags(x) save_flags(&x)
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static inline void __deprecated restore_flags(unsigned long x)
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{
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local_irq_restore(x);
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}
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static inline void __deprecated save_and_cli(unsigned long *x)
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{
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local_irq_save(*x);
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}
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#define save_and_cli(x) save_and_cli(&x)
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#endif /* CONFIG_SMP */
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/* Some architectures might implement lazy enabling/disabling of
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* interrupts. In some cases, such as stop_machine, we might want
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* to ensure that after a local_irq_disable(), interrupts have
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* really been disabled in hardware. Such architectures need to
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* implement the following hook.
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*/
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#ifndef hard_irq_disable
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#define hard_irq_disable() do { } while(0)
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#endif
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/* PLEASE, avoid to allocate new softirqs, if you need not _really_ high
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frequency threaded job scheduling. For almost all the purposes
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tasklets are more than enough. F.e. all serial device BHs et
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al. should be converted to tasklets, not to softirqs.
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*/
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enum
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{
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HI_SOFTIRQ=0,
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TIMER_SOFTIRQ,
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NET_TX_SOFTIRQ,
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NET_RX_SOFTIRQ,
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BLOCK_SOFTIRQ,
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TASKLET_SOFTIRQ,
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SCHED_SOFTIRQ,
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#ifdef CONFIG_HIGH_RES_TIMERS
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HRTIMER_SOFTIRQ,
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#endif
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};
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/* softirq mask and active fields moved to irq_cpustat_t in
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* asm/hardirq.h to get better cache usage. KAO
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*/
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struct softirq_action
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{
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void (*action)(struct softirq_action *);
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void *data;
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};
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asmlinkage void do_softirq(void);
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extern void open_softirq(int nr, void (*action)(struct softirq_action*), void *data);
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extern void softirq_init(void);
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#define __raise_softirq_irqoff(nr) do { or_softirq_pending(1UL << (nr)); } while (0)
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extern void FASTCALL(raise_softirq_irqoff(unsigned int nr));
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extern void FASTCALL(raise_softirq(unsigned int nr));
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/* Tasklets --- multithreaded analogue of BHs.
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Main feature differing them of generic softirqs: tasklet
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is running only on one CPU simultaneously.
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Main feature differing them of BHs: different tasklets
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may be run simultaneously on different CPUs.
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Properties:
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* If tasklet_schedule() is called, then tasklet is guaranteed
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to be executed on some cpu at least once after this.
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* If the tasklet is already scheduled, but its excecution is still not
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started, it will be executed only once.
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* If this tasklet is already running on another CPU (or schedule is called
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from tasklet itself), it is rescheduled for later.
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* Tasklet is strictly serialized wrt itself, but not
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wrt another tasklets. If client needs some intertask synchronization,
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he makes it with spinlocks.
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*/
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struct tasklet_struct
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{
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struct tasklet_struct *next;
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unsigned long state;
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atomic_t count;
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void (*func)(unsigned long);
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unsigned long data;
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};
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#define DECLARE_TASKLET(name, func, data) \
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struct tasklet_struct name = { NULL, 0, ATOMIC_INIT(0), func, data }
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#define DECLARE_TASKLET_DISABLED(name, func, data) \
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struct tasklet_struct name = { NULL, 0, ATOMIC_INIT(1), func, data }
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enum
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{
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TASKLET_STATE_SCHED, /* Tasklet is scheduled for execution */
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TASKLET_STATE_RUN /* Tasklet is running (SMP only) */
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};
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#ifdef CONFIG_SMP
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static inline int tasklet_trylock(struct tasklet_struct *t)
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{
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return !test_and_set_bit(TASKLET_STATE_RUN, &(t)->state);
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}
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static inline void tasklet_unlock(struct tasklet_struct *t)
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{
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smp_mb__before_clear_bit();
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clear_bit(TASKLET_STATE_RUN, &(t)->state);
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}
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static inline void tasklet_unlock_wait(struct tasklet_struct *t)
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{
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while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { barrier(); }
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}
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#else
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#define tasklet_trylock(t) 1
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#define tasklet_unlock_wait(t) do { } while (0)
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#define tasklet_unlock(t) do { } while (0)
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#endif
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extern void FASTCALL(__tasklet_schedule(struct tasklet_struct *t));
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static inline void tasklet_schedule(struct tasklet_struct *t)
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{
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if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
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__tasklet_schedule(t);
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}
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extern void FASTCALL(__tasklet_hi_schedule(struct tasklet_struct *t));
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static inline void tasklet_hi_schedule(struct tasklet_struct *t)
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{
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if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
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__tasklet_hi_schedule(t);
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}
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static inline void tasklet_disable_nosync(struct tasklet_struct *t)
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{
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atomic_inc(&t->count);
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smp_mb__after_atomic_inc();
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}
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static inline void tasklet_disable(struct tasklet_struct *t)
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{
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tasklet_disable_nosync(t);
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tasklet_unlock_wait(t);
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smp_mb();
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}
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static inline void tasklet_enable(struct tasklet_struct *t)
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{
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smp_mb__before_atomic_dec();
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atomic_dec(&t->count);
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}
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static inline void tasklet_hi_enable(struct tasklet_struct *t)
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{
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smp_mb__before_atomic_dec();
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atomic_dec(&t->count);
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}
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extern void tasklet_kill(struct tasklet_struct *t);
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extern void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu);
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extern void tasklet_init(struct tasklet_struct *t,
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void (*func)(unsigned long), unsigned long data);
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/*
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* Autoprobing for irqs:
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*
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* probe_irq_on() and probe_irq_off() provide robust primitives
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* for accurate IRQ probing during kernel initialization. They are
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* reasonably simple to use, are not "fooled" by spurious interrupts,
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* and, unlike other attempts at IRQ probing, they do not get hung on
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* stuck interrupts (such as unused PS2 mouse interfaces on ASUS boards).
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*
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* For reasonably foolproof probing, use them as follows:
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*
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* 1. clear and/or mask the device's internal interrupt.
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* 2. sti();
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* 3. irqs = probe_irq_on(); // "take over" all unassigned idle IRQs
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* 4. enable the device and cause it to trigger an interrupt.
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* 5. wait for the device to interrupt, using non-intrusive polling or a delay.
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* 6. irq = probe_irq_off(irqs); // get IRQ number, 0=none, negative=multiple
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* 7. service the device to clear its pending interrupt.
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* 8. loop again if paranoia is required.
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*
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* probe_irq_on() returns a mask of allocated irq's.
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*
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* probe_irq_off() takes the mask as a parameter,
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* and returns the irq number which occurred,
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* or zero if none occurred, or a negative irq number
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* if more than one irq occurred.
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*/
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#if defined(CONFIG_GENERIC_HARDIRQS) && !defined(CONFIG_GENERIC_IRQ_PROBE)
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static inline unsigned long probe_irq_on(void)
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{
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return 0;
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}
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static inline int probe_irq_off(unsigned long val)
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{
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return 0;
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}
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static inline unsigned int probe_irq_mask(unsigned long val)
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{
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return 0;
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}
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#else
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extern unsigned long probe_irq_on(void); /* returns 0 on failure */
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extern int probe_irq_off(unsigned long); /* returns 0 or negative on failure */
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extern unsigned int probe_irq_mask(unsigned long); /* returns mask of ISA interrupts */
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#endif
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#ifdef CONFIG_PROC_FS
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/* Initialize /proc/irq/ */
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extern void init_irq_proc(void);
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#else
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static inline void init_irq_proc(void)
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{
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}
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#endif
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#endif
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