Merge branch 'master' of git://git.kernel.org/pub/scm/fs/xfs/xfs
[linux-2.6] / arch / x86 / kernel / irq_64.c
1 /*
2  *      Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
3  *
4  * This file contains the lowest level x86_64-specific interrupt
5  * entry and irq statistics code. All the remaining irq logic is
6  * done by the generic kernel/irq/ code and in the
7  * x86_64-specific irq controller code. (e.g. i8259.c and
8  * io_apic.c.)
9  */
10
11 #include <linux/kernel_stat.h>
12 #include <linux/interrupt.h>
13 #include <linux/seq_file.h>
14 #include <linux/module.h>
15 #include <linux/delay.h>
16 #include <linux/ftrace.h>
17 #include <linux/uaccess.h>
18 #include <linux/smp.h>
19 #include <asm/io_apic.h>
20 #include <asm/idle.h>
21 #include <asm/apic.h>
22
23 DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
24 EXPORT_PER_CPU_SYMBOL(irq_stat);
25
26 DEFINE_PER_CPU(struct pt_regs *, irq_regs);
27 EXPORT_PER_CPU_SYMBOL(irq_regs);
28
29 /*
30  * Probabilistic stack overflow check:
31  *
32  * Only check the stack in process context, because everything else
33  * runs on the big interrupt stacks. Checking reliably is too expensive,
34  * so we just check from interrupts.
35  */
36 static inline void stack_overflow_check(struct pt_regs *regs)
37 {
38 #ifdef CONFIG_DEBUG_STACKOVERFLOW
39         u64 curbase = (u64)task_stack_page(current);
40
41         WARN_ONCE(regs->sp >= curbase &&
42                   regs->sp <= curbase + THREAD_SIZE &&
43                   regs->sp <  curbase + sizeof(struct thread_info) +
44                                         sizeof(struct pt_regs) + 128,
45
46                   "do_IRQ: %s near stack overflow (cur:%Lx,sp:%lx)\n",
47                         current->comm, curbase, regs->sp);
48 #endif
49 }
50
51 bool handle_irq(unsigned irq, struct pt_regs *regs)
52 {
53         struct irq_desc *desc;
54
55         stack_overflow_check(regs);
56
57         desc = irq_to_desc(irq);
58         if (unlikely(!desc))
59                 return false;
60
61         generic_handle_irq_desc(irq, desc);
62         return true;
63 }
64
65 #ifdef CONFIG_HOTPLUG_CPU
66 /* A cpu has been removed from cpu_online_mask.  Reset irq affinities. */
67 void fixup_irqs(void)
68 {
69         unsigned int irq;
70         static int warned;
71         struct irq_desc *desc;
72
73         for_each_irq_desc(irq, desc) {
74                 int break_affinity = 0;
75                 int set_affinity = 1;
76                 const struct cpumask *affinity;
77
78                 if (!desc)
79                         continue;
80                 if (irq == 2)
81                         continue;
82
83                 /* interrupt's are disabled at this point */
84                 spin_lock(&desc->lock);
85
86                 affinity = desc->affinity;
87                 if (!irq_has_action(irq) ||
88                     cpumask_equal(affinity, cpu_online_mask)) {
89                         spin_unlock(&desc->lock);
90                         continue;
91                 }
92
93                 if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
94                         break_affinity = 1;
95                         affinity = cpu_all_mask;
96                 }
97
98                 if (desc->chip->mask)
99                         desc->chip->mask(irq);
100
101                 if (desc->chip->set_affinity)
102                         desc->chip->set_affinity(irq, affinity);
103                 else if (!(warned++))
104                         set_affinity = 0;
105
106                 if (desc->chip->unmask)
107                         desc->chip->unmask(irq);
108
109                 spin_unlock(&desc->lock);
110
111                 if (break_affinity && set_affinity)
112                         printk("Broke affinity for irq %i\n", irq);
113                 else if (!set_affinity)
114                         printk("Cannot set affinity for irq %i\n", irq);
115         }
116
117         /* That doesn't seem sufficient.  Give it 1ms. */
118         local_irq_enable();
119         mdelay(1);
120         local_irq_disable();
121 }
122 #endif
123
124 extern void call_softirq(void);
125
126 asmlinkage void do_softirq(void)
127 {
128         __u32 pending;
129         unsigned long flags;
130
131         if (in_interrupt())
132                 return;
133
134         local_irq_save(flags);
135         pending = local_softirq_pending();
136         /* Switch to interrupt stack */
137         if (pending) {
138                 call_softirq();
139                 WARN_ON_ONCE(softirq_count());
140         }
141         local_irq_restore(flags);
142 }