/* *  arch/s390/kernel/s390_ext.c * *  S390 version *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation *    Author(s): Holger Smolinski (Holger.Smolinski@de.ibm.com), *               Martin Schwidefsky (schwidefsky@de.ibm.com) */#include <linux/module.h>#include <linux/kernel.h>#include <linux/slab.h>#include <linux/errno.h>#include <linux/kernel_stat.h>#include <linux/interrupt.h>#include <asm/lowcore.h>#include <asm/s390_ext.h>#include <asm/irq.h>/* * Simple hash strategy: index = code & 0xff; * ext_int_hash[index] is the start of the list for all external interrupts * that hash to this index. With the current set of external interrupts  * (0x1202 external call, 0x1004 cpu timer, 0x2401 hwc console, 0x4000 * iucv and 0x2603 pfault) this is always the first element.  */ext_int_info_t *ext_int_hash[256] = { 0, };int register_external_interrupt(__u16 code, ext_int_handler_t handler){        ext_int_info_t *p;        int index;	p = (ext_int_info_t *) kmalloc(sizeof(ext_int_info_t), GFP_ATOMIC);        if (p == NULL)                return -ENOMEM;        p->code = code;        p->handler = handler;        index = code & 0xff;        p->next = ext_int_hash[index];        ext_int_hash[index] = p;        return 0;}int register_early_external_interrupt(__u16 code, ext_int_handler_t handler,				      ext_int_info_t *p){        int index;        if (p == NULL)                return -EINVAL;        p->code = code;        p->handler = handler;        index = code & 0xff;        p->next = ext_int_hash[index];        ext_int_hash[index] = p;        return 0;}int unregister_external_interrupt(__u16 code, ext_int_handler_t handler){        ext_int_info_t *p, *q;        int index;        index = code & 0xff;        q = NULL;        p = ext_int_hash[index];        while (p != NULL) {                if (p->code == code && p->handler == handler)                        break;                q = p;                p = p->next;        }        if (p == NULL)                return -ENOENT;        if (q != NULL)                q->next = p->next;        else                ext_int_hash[index] = p->next;	kfree(p);        return 0;}int unregister_early_external_interrupt(__u16 code, ext_int_handler_t handler,					ext_int_info_t *p){	ext_int_info_t *q;	int index;	if (p == NULL || p->code != code || p->handler != handler)		return -EINVAL;	index = code & 0xff;	q = ext_int_hash[index];	if (p != q) {		while (q != NULL) {			if (q->next == p)				break;			q = q->next;		}		if (q == NULL)			return -ENOENT;		q->next = p->next;	} else		ext_int_hash[index] = p->next;	return 0;}void do_extint(struct pt_regs *regs, unsigned short code){        ext_int_info_t *p;        int index;	irq_enter();	asm volatile ("mc 0,0");	if (S390_lowcore.int_clock >= S390_lowcore.jiffy_timer)		account_ticks(regs);	kstat_cpu(smp_processor_id()).irqs[EXTERNAL_INTERRUPT]++;        index = code & 0xff;	for (p = ext_int_hash[index]; p; p = p->next) {		if (likely(p->code == code)) {			if (likely(p->handler))				p->handler(regs, code);		}	}	irq_exit();}EXPORT_SYMBOL(register_external_interrupt);EXPORT_SYMBOL(unregister_external_interrupt);