Merge git://git.tuxdriver.com/git/netdev-jwl
[linux-2.6] / arch / s390 / kernel / irq.c
1 /*
2  *  arch/s390/kernel/irq.c
3  *
4  *  S390 version
5  *    Copyright (C) 2004 IBM Deutschland Entwicklung GmbH, IBM Corporation
6  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
7  *
8  * This file contains interrupt related functions.
9  */
10
11 #include <linux/module.h>
12 #include <linux/kernel.h>
13 #include <linux/kernel_stat.h>
14 #include <linux/interrupt.h>
15 #include <linux/seq_file.h>
16 #include <linux/cpu.h>
17
18 /*
19  * show_interrupts is needed by /proc/interrupts.
20  */
21 int show_interrupts(struct seq_file *p, void *v)
22 {
23         static const char *intrclass_names[] = { "EXT", "I/O", };
24         int i = *(loff_t *) v, j;
25
26         if (i == 0) {
27                 seq_puts(p, "           ");
28                 for_each_online_cpu(j)
29                         seq_printf(p, "CPU%d       ",j);
30                 seq_putc(p, '\n');
31         }
32
33         if (i < NR_IRQS) {
34                 seq_printf(p, "%s: ", intrclass_names[i]);
35 #ifndef CONFIG_SMP
36                 seq_printf(p, "%10u ", kstat_irqs(i));
37 #else
38                 for_each_online_cpu(j)
39                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
40 #endif
41                 seq_putc(p, '\n');
42
43         }
44
45         return 0;
46 }
47
48 /*
49  * For compatibilty only. S/390 specific setup of interrupts et al. is done
50  * much later in init_channel_subsystem().
51  */
52 void __init
53 init_IRQ(void)
54 {
55         /* nothing... */
56 }
57
58 /*
59  * Switch to the asynchronous interrupt stack for softirq execution.
60  */
61 extern void __do_softirq(void);
62
63 asmlinkage void do_softirq(void)
64 {
65         unsigned long flags, old, new;
66
67         if (in_interrupt())
68                 return;
69
70         local_irq_save(flags);
71
72         account_system_vtime(current);
73
74         local_bh_disable();
75
76         if (local_softirq_pending()) {
77                 /* Get current stack pointer. */
78                 asm volatile("la %0,0(15)" : "=a" (old));
79                 /* Check against async. stack address range. */
80                 new = S390_lowcore.async_stack;
81                 if (((new - old) >> (PAGE_SHIFT + THREAD_ORDER)) != 0) {
82                         /* Need to switch to the async. stack. */
83                         new -= STACK_FRAME_OVERHEAD;
84                         ((struct stack_frame *) new)->back_chain = old;
85
86                         asm volatile("   la    15,0(%0)\n"
87                                      "   basr  14,%2\n"
88                                      "   la    15,0(%1)\n"
89                                      : : "a" (new), "a" (old),
90                                          "a" (__do_softirq)
91                                      : "0", "1", "2", "3", "4", "5", "14",
92                                        "cc", "memory" );
93                 } else
94                         /* We are already on the async stack. */
95                         __do_softirq();
96         }
97
98         account_system_vtime(current);
99
100         __local_bh_enable();
101
102         local_irq_restore(flags);
103 }
104
105 EXPORT_SYMBOL(do_softirq);