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 if (local_softirq_pending()) { 73 /* Get current stack pointer. */ 74 asm volatile("la %0,0(15)" : "=a" (old)); 75 /* Check against async. stack address range. */ 76 new = S390_lowcore.async_stack; 77 if (((new - old) >> (PAGE_SHIFT + THREAD_ORDER)) != 0) { 78 /* Need to switch to the async. stack. */ 79 new -= STACK_FRAME_OVERHEAD; 80 ((struct stack_frame *) new)->back_chain = old; 81 82 asm volatile(" la 15,0(%0)\n" 83 " basr 14,%2\n" 84 " la 15,0(%1)\n" 85 : : "a" (new), "a" (old), 86 "a" (__do_softirq) 87 : "0", "1", "2", "3", "4", "5", "14", 88 "cc", "memory" ); 89 } else 90 /* We are already on the async stack. */ 91 __do_softirq(); 92 } 93 94 local_irq_restore(flags); 95 } 96 97 EXPORT_SYMBOL(do_softirq); 98