51 lines
1.6 KiB
C
51 lines
1.6 KiB
C
/* hardirq.h: PA-RISC hard IRQ support.
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*
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* Copyright (C) 2001 Matthew Wilcox <matthew@wil.cx>
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*
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* The locking is really quite interesting. There's a cpu-local
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* count of how many interrupts are being handled, and a global
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* lock. An interrupt can only be serviced if the global lock
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* is free. You can't be sure no more interrupts are being
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* serviced until you've acquired the lock and then checked
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* all the per-cpu interrupt counts are all zero. It's a specialised
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* br_lock, and that's exactly how Sparc does it. We don't because
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* it's more locking for us. This way is lock-free in the interrupt path.
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*/
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#ifndef _PARISC_HARDIRQ_H
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#define _PARISC_HARDIRQ_H
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#include <linux/config.h>
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#include <linux/threads.h>
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#include <linux/cache.h>
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typedef struct {
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unsigned long __softirq_pending; /* set_bit is used on this */
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unsigned int __syscall_count;
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struct task_struct * __ksoftirqd_task;
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unsigned long idle_timestamp;
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} ____cacheline_aligned irq_cpustat_t;
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#include <linux/irq_cpustat.h> /* Standard mappings for irq_cpustat_t above */
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#define HARDIRQ_BITS 16
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/*
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* The hardirq mask has to be large enough to have space for potentially all IRQ sources
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* in the system nesting on a single CPU:
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*/
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#if (1 << HARDIRQ_BITS) < NR_IRQS
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# error HARDIRQ_BITS is too low!
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#endif
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#define irq_enter() (preempt_count() += HARDIRQ_OFFSET)
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#define irq_exit() \
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do { \
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preempt_count() -= IRQ_EXIT_OFFSET; \
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if (!in_interrupt() && softirq_pending(smp_processor_id())) \
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do_softirq(); \
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preempt_enable_no_resched(); \
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} while (0)
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#endif /* _PARISC_HARDIRQ_H */
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