Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 | /* hardirq.h: PA-RISC hard IRQ support. * * Copyright (C) 2001 Matthew Wilcox <matthew@wil.cx> * * The locking is really quite interesting. There's a cpu-local * count of how many interrupts are being handled, and a global * lock. An interrupt can only be serviced if the global lock * is free. You can't be sure no more interrupts are being * serviced until you've acquired the lock and then checked * all the per-cpu interrupt counts are all zero. It's a specialised * br_lock, and that's exactly how Sparc does it. We don't because * it's more locking for us. This way is lock-free in the interrupt path. */ #ifndef _PARISC_HARDIRQ_H #define _PARISC_HARDIRQ_H #include <linux/config.h> #include <linux/threads.h> typedef struct { unsigned long __softirq_pending; /* set_bit is used on this */ unsigned int __local_irq_count; unsigned int __local_bh_count; unsigned int __syscall_count; struct task_struct * __ksoftirqd_task; } ____cacheline_aligned irq_cpustat_t; #include <linux/irq_cpustat.h> /* Standard mappings for irq_cpustat_t above */ /* * Are we in an interrupt context? Either doing bottom half * or hardware interrupt processing? */ #define in_interrupt() ({ int __cpu = smp_processor_id(); \ (local_irq_count(__cpu) + local_bh_count(__cpu) != 0); }) #define in_irq() ({ int __cpu = smp_processor_id(); \ (local_irq_count(__cpu) != 0); }) #ifndef CONFIG_SMP #define hardirq_trylock(cpu) (local_irq_count(cpu) == 0) #define hardirq_endlock(cpu) do { } while (0) #define irq_enter(cpu, irq) (local_irq_count(cpu)++) #define irq_exit(cpu, irq) (local_irq_count(cpu)--) #define synchronize_irq() barrier() #else #include <asm/system.h> #include <asm/atomic.h> #include <linux/spinlock.h> #include <asm/smp.h> extern int global_irq_holder; extern spinlock_t global_irq_lock; static inline int irqs_running (void) { int i; for (i = 0; i < smp_num_cpus; i++) if (local_irq_count(i)) return 1; return 0; } static inline void release_irqlock(int cpu) { /* if we didn't own the irq lock, just ignore.. */ if (global_irq_holder == (unsigned char) cpu) { global_irq_holder = NO_PROC_ID; spin_unlock(&global_irq_lock); } } static inline void irq_enter(int cpu, int irq) { ++local_irq_count(cpu); while (spin_is_locked(&global_irq_lock)) barrier(); } static inline void irq_exit(int cpu, int irq) { --local_irq_count(cpu); } static inline int hardirq_trylock(int cpu) { return !local_irq_count(cpu) && !spin_is_locked (&global_irq_lock); } #define hardirq_endlock(cpu) do { } while (0) extern void synchronize_irq(void); #endif /* CONFIG_SMP */ #endif /* _PARISC_HARDIRQ_H */ |