xref: /openbmc/linux/arch/s390/kernel/irq.c (revision 64c70b1c)
1 /*
2  *  arch/s390/kernel/irq.c
3  *
4  *    Copyright IBM Corp. 2004,2007
5  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
6  *		 Thomas Spatzier (tspat@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 #include <linux/proc_fs.h>
18 #include <linux/profile.h>
19 
20 /*
21  * show_interrupts is needed by /proc/interrupts.
22  */
23 int show_interrupts(struct seq_file *p, void *v)
24 {
25 	static const char *intrclass_names[] = { "EXT", "I/O", };
26 	int i = *(loff_t *) v, j;
27 
28 	if (i == 0) {
29 		seq_puts(p, "           ");
30 		for_each_online_cpu(j)
31 			seq_printf(p, "CPU%d       ",j);
32 		seq_putc(p, '\n');
33 	}
34 
35 	if (i < NR_IRQS) {
36 		seq_printf(p, "%s: ", intrclass_names[i]);
37 #ifndef CONFIG_SMP
38 		seq_printf(p, "%10u ", kstat_irqs(i));
39 #else
40 		for_each_online_cpu(j)
41 			seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
42 #endif
43                 seq_putc(p, '\n');
44 
45         }
46 
47         return 0;
48 }
49 
50 /*
51  * For compatibilty only. S/390 specific setup of interrupts et al. is done
52  * much later in init_channel_subsystem().
53  */
54 void __init
55 init_IRQ(void)
56 {
57 	/* nothing... */
58 }
59 
60 /*
61  * Switch to the asynchronous interrupt stack for softirq execution.
62  */
63 extern void __do_softirq(void);
64 
65 asmlinkage void do_softirq(void)
66 {
67 	unsigned long flags, old, new;
68 
69 	if (in_interrupt())
70 		return;
71 
72 	local_irq_save(flags);
73 
74 	if (local_softirq_pending()) {
75 		/* Get current stack pointer. */
76 		asm volatile("la %0,0(15)" : "=a" (old));
77 		/* Check against async. stack address range. */
78 		new = S390_lowcore.async_stack;
79 		if (((new - old) >> (PAGE_SHIFT + THREAD_ORDER)) != 0) {
80 			/* Need to switch to the async. stack. */
81 			new -= STACK_FRAME_OVERHEAD;
82 			((struct stack_frame *) new)->back_chain = old;
83 
84 			asm volatile("   la    15,0(%0)\n"
85 				     "   basr  14,%2\n"
86 				     "   la    15,0(%1)\n"
87 				     : : "a" (new), "a" (old),
88 				         "a" (__do_softirq)
89 				     : "0", "1", "2", "3", "4", "5", "14",
90 				       "cc", "memory" );
91 		} else
92 			/* We are already on the async stack. */
93 			__do_softirq();
94 	}
95 
96 	local_irq_restore(flags);
97 }
98 EXPORT_SYMBOL(do_softirq);
99 
100 void init_irq_proc(void)
101 {
102 	struct proc_dir_entry *root_irq_dir;
103 
104 	root_irq_dir = proc_mkdir("irq", NULL);
105 	create_prof_cpu_mask(root_irq_dir);
106 }
107