[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / ppc64 / kernel / irq.c

/*
 *  arch/ppc/kernel/irq.c
 *
 *  Derived from arch/i386/kernel/irq.c
 *    Copyright (C) 1992 Linus Torvalds
 *  Adapted from arch/i386 by Gary Thomas
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *  Updated and modified by Cort Dougan (cort@cs.nmt.edu)
 *    Copyright (C) 1996 Cort Dougan
 *  Adapted for Power Macintosh by Paul Mackerras
 *    Copyright (C) 1996 Paul Mackerras (paulus@cs.anu.edu.au)
 *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 * This file contains the code used by various IRQ handling routines:
 * asking for different IRQ's should be done through these routines
 * instead of just grabbing them. Thus setups with different IRQ numbers
 * shouldn't result in any weird surprises, and installing new handlers
 * should be easier.
 */

#include <linux/errno.h>
#include <linux/module.h>
#include <linux/threads.h>
#include <linux/kernel_stat.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/timex.h>
#include <linux/config.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/proc_fs.h>
#include <linux/random.h>
#include <linux/kallsyms.h>
#include <linux/profile.h>
#include <linux/bitops.h>

#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/irq.h>
#include <asm/cache.h>
#include <asm/prom.h>
#include <asm/ptrace.h>
#include <asm/iseries/it_lp_queue.h>
#include <asm/machdep.h>
#include <asm/paca.h>

#ifdef CONFIG_SMP
extern void iSeries_smp_message_recv( struct pt_regs * );
#endif

extern irq_desc_t irq_desc[NR_IRQS];
EXPORT_SYMBOL(irq_desc);

int distribute_irqs = 1;
int __irq_offset_value;
int ppc_spurious_interrupts;
u64 ppc64_interrupt_controller;

int show_interrupts(struct seq_file *p, void *v)
{
	int i = *(loff_t *) v, j;
	struct irqaction * action;
	irq_desc_t *desc;
	unsigned long flags;

	if (i == 0) {
		seq_printf(p, "           ");
		for (j=0; j<NR_CPUS; j++) {
			if (cpu_online(j))
				seq_printf(p, "CPU%d       ",j);
		}
		seq_putc(p, '\n');
	}

	if (i < NR_IRQS) {
		desc = get_irq_desc(i);
		spin_lock_irqsave(&desc->lock, flags);
		action = desc->action;
		if (!action || !action->handler)
			goto skip;
		seq_printf(p, "%3d: ", i);
#ifdef CONFIG_SMP
		for (j = 0; j < NR_CPUS; j++) {
			if (cpu_online(j))
				seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
		}
#else
		seq_printf(p, "%10u ", kstat_irqs(i));
#endif /* CONFIG_SMP */
		if (desc->handler)
			seq_printf(p, " %s ", desc->handler->typename );
		else
			seq_printf(p, "  None      ");
		seq_printf(p, "%s", (desc->status & IRQ_LEVEL) ? "Level " : "Edge  ");
		seq_printf(p, "    %s",action->name);
		for (action=action->next; action; action = action->next)
			seq_printf(p, ", %s", action->name);
		seq_putc(p, '\n');
skip:
		spin_unlock_irqrestore(&desc->lock, flags);
	} else if (i == NR_IRQS)
		seq_printf(p, "BAD: %10u\n", ppc_spurious_interrupts);
	return 0;
}

#ifdef CONFIG_HOTPLUG_CPU
void fixup_irqs(cpumask_t map)
{
	unsigned int irq;
	static int warned;

	for_each_irq(irq) {
		cpumask_t mask;

		if (irq_desc[irq].status & IRQ_PER_CPU)
			continue;

		cpus_and(mask, irq_affinity[irq], map);
		if (any_online_cpu(mask) == NR_CPUS) {
			printk("Breaking affinity for irq %i\n", irq);
			mask = map;
		}
		if (irq_desc[irq].handler->set_affinity)
			irq_desc[irq].handler->set_affinity(irq, mask);
		else if (irq_desc[irq].action && !(warned++))
			printk("Cannot set affinity for irq %i\n", irq);
	}

	local_irq_enable();
	mdelay(1);
	local_irq_disable();
}
#endif

#ifdef CONFIG_PPC_ISERIES
void do_IRQ(struct pt_regs *regs)
{
	struct paca_struct *lpaca;

	irq_enter();

#ifdef CONFIG_DEBUG_STACKOVERFLOW
	/* Debugging check for stack overflow: is there less than 2KB free? */
	{
		long sp;

		sp = __get_SP() & (THREAD_SIZE-1);

		if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
			printk("do_IRQ: stack overflow: %ld\n",
				sp - sizeof(struct thread_info));
			dump_stack();
		}
	}
#endif

	lpaca = get_paca();
#ifdef CONFIG_SMP
	if (lpaca->lppaca.int_dword.fields.ipi_cnt) {
		lpaca->lppaca.int_dword.fields.ipi_cnt = 0;
		iSeries_smp_message_recv(regs);
	}
#endif /* CONFIG_SMP */
	if (hvlpevent_is_pending())
		process_hvlpevents(regs);

	irq_exit();

	if (lpaca->lppaca.int_dword.fields.decr_int) {
		lpaca->lppaca.int_dword.fields.decr_int = 0;
		/* Signal a fake decrementer interrupt */
		timer_interrupt(regs);
	}
}

#else	/* CONFIG_PPC_ISERIES */

void do_IRQ(struct pt_regs *regs)
{
	int irq;
#ifdef CONFIG_IRQSTACKS
	struct thread_info *curtp, *irqtp;
#endif

	irq_enter();

#ifdef CONFIG_DEBUG_STACKOVERFLOW
	/* Debugging check for stack overflow: is there less than 2KB free? */
	{
		long sp;

		sp = __get_SP() & (THREAD_SIZE-1);

		if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
			printk("do_IRQ: stack overflow: %ld\n",
				sp - sizeof(struct thread_info));
			dump_stack();
		}
	}
#endif

	irq = ppc_md.get_irq(regs);

	if (irq >= 0) {
#ifdef CONFIG_IRQSTACKS
		/* Switch to the irq stack to handle this */
		curtp = current_thread_info();
		irqtp = hardirq_ctx[smp_processor_id()];
		if (curtp != irqtp) {
			irqtp->task = curtp->task;
			irqtp->flags = 0;
			call___do_IRQ(irq, regs, irqtp);
			irqtp->task = NULL;
			if (irqtp->flags)
				set_bits(irqtp->flags, &curtp->flags);
		} else
#endif
			__do_IRQ(irq, regs);
	} else
		/* That's not SMP safe ... but who cares ? */
		ppc_spurious_interrupts++;

	irq_exit();
}
#endif	/* CONFIG_PPC_ISERIES */

void __init init_IRQ(void)
{
	static int once = 0;

	if (once)
		return;

	once++;

	ppc_md.init_IRQ();
	irq_ctx_init();
}

#ifndef CONFIG_PPC_ISERIES
/*
 * Virtual IRQ mapping code, used on systems with XICS interrupt controllers.
 */

#define UNDEFINED_IRQ 0xffffffff
unsigned int virt_irq_to_real_map[NR_IRQS];

/*
 * Don't use virtual irqs 0, 1, 2 for devices.
 * The pcnet32 driver considers interrupt numbers < 2 to be invalid,
 * and 2 is the XICS IPI interrupt.
 * We limit virtual irqs to 17 less than NR_IRQS so that when we
 * offset them by 16 (to reserve the first 16 for ISA interrupts)
 * we don't end up with an interrupt number >= NR_IRQS.
 */
#define MIN_VIRT_IRQ	3
#define MAX_VIRT_IRQ	(NR_IRQS - NUM_ISA_INTERRUPTS - 1)
#define NR_VIRT_IRQS	(MAX_VIRT_IRQ - MIN_VIRT_IRQ + 1)

void
virt_irq_init(void)
{
	int i;
	for (i = 0; i < NR_IRQS; i++)
		virt_irq_to_real_map[i] = UNDEFINED_IRQ;
}

/* Create a mapping for a real_irq if it doesn't already exist.
 * Return the virtual irq as a convenience.
 */
int virt_irq_create_mapping(unsigned int real_irq)
{
	unsigned int virq, first_virq;
	static int warned;

	if (ppc64_interrupt_controller == IC_OPEN_PIC)
		return real_irq;	/* no mapping for openpic (for now) */

	if (ppc64_interrupt_controller == IC_CELL_PIC)
		return real_irq;	/* no mapping for iic either */

	/* don't map interrupts < MIN_VIRT_IRQ */
	if (real_irq < MIN_VIRT_IRQ) {
		virt_irq_to_real_map[real_irq] = real_irq;
		return real_irq;
	}

	/* map to a number between MIN_VIRT_IRQ and MAX_VIRT_IRQ */
	virq = real_irq;
	if (virq > MAX_VIRT_IRQ)
		virq = (virq % NR_VIRT_IRQS) + MIN_VIRT_IRQ;

	/* search for this number or a free slot */
	first_virq = virq;
	while (virt_irq_to_real_map[virq] != UNDEFINED_IRQ) {
		if (virt_irq_to_real_map[virq] == real_irq)
			return virq;
		if (++virq > MAX_VIRT_IRQ)
			virq = MIN_VIRT_IRQ;
		if (virq == first_virq)
			goto nospace;	/* oops, no free slots */
	}

	virt_irq_to_real_map[virq] = real_irq;
	return virq;

 nospace:
	if (!warned) {
		printk(KERN_CRIT "Interrupt table is full\n");
		printk(KERN_CRIT "Increase NR_IRQS (currently %d) "
		       "in your kernel sources and rebuild.\n", NR_IRQS);
		warned = 1;
	}
	return NO_IRQ;
}

/*
 * In most cases will get a hit on the very first slot checked in the
 * virt_irq_to_real_map.  Only when there are a large number of
 * IRQs will this be expensive.
 */
unsigned int real_irq_to_virt_slowpath(unsigned int real_irq)
{
	unsigned int virq;
	unsigned int first_virq;

	virq = real_irq;

	if (virq > MAX_VIRT_IRQ)
		virq = (virq % NR_VIRT_IRQS) + MIN_VIRT_IRQ;

	first_virq = virq;

	do {
		if (virt_irq_to_real_map[virq] == real_irq)
			return virq;

		virq++;

		if (virq >= MAX_VIRT_IRQ)
			virq = 0;

	} while (first_virq != virq);

	return NO_IRQ;

}

#endif /* CONFIG_PPC_ISERIES */

#ifdef CONFIG_IRQSTACKS
struct thread_info *softirq_ctx[NR_CPUS];
struct thread_info *hardirq_ctx[NR_CPUS];

void irq_ctx_init(void)
{
	struct thread_info *tp;
	int i;

	for_each_cpu(i) {
		memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
		tp = softirq_ctx[i];
		tp->cpu = i;
		tp->preempt_count = SOFTIRQ_OFFSET;

		memset((void *)hardirq_ctx[i], 0, THREAD_SIZE);
		tp = hardirq_ctx[i];
		tp->cpu = i;
		tp->preempt_count = HARDIRQ_OFFSET;
	}
}

void do_softirq(void)
{
	unsigned long flags;
	struct thread_info *curtp, *irqtp;

	if (in_interrupt())
		return;

	local_irq_save(flags);

	if (local_softirq_pending()) {
		curtp = current_thread_info();
		irqtp = softirq_ctx[smp_processor_id()];
		irqtp->task = curtp->task;
		call_do_softirq(irqtp);
		irqtp->task = NULL;
	}

	local_irq_restore(flags);
}
EXPORT_SYMBOL(do_softirq);

#endif /* CONFIG_IRQSTACKS */

static int __init setup_noirqdistrib(char *str)
{
	distribute_irqs = 0;
	return 1;
}

__setup("noirqdistrib", setup_noirqdistrib);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* arch/ppc/kernel/irq.c
	3	*
	4	* Derived from arch/i386/kernel/irq.c
	5	* Copyright (C) 1992 Linus Torvalds
	6	* Adapted from arch/i386 by Gary Thomas
	7	* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
	8	* Updated and modified by Cort Dougan (cort@cs.nmt.edu)
	9	* Copyright (C) 1996 Cort Dougan
	10	* Adapted for Power Macintosh by Paul Mackerras
	11	* Copyright (C) 1996 Paul Mackerras (paulus@cs.anu.edu.au)
	12	* Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
	13	*
	14	* This program is free software; you can redistribute it and/or
	15	* modify it under the terms of the GNU General Public License
	16	* as published by the Free Software Foundation; either version
	17	* 2 of the License, or (at your option) any later version.
	18	*
	19	* This file contains the code used by various IRQ handling routines:
	20	* asking for different IRQ's should be done through these routines
	21	* instead of just grabbing them. Thus setups with different IRQ numbers
	22	* shouldn't result in any weird surprises, and installing new handlers
	23	* should be easier.
	24	*/
	25
	26	#include <linux/errno.h>
	27	#include <linux/module.h>
	28	#include <linux/threads.h>
	29	#include <linux/kernel_stat.h>
	30	#include <linux/signal.h>
	31	#include <linux/sched.h>
	32	#include <linux/ioport.h>
	33	#include <linux/interrupt.h>
	34	#include <linux/timex.h>
	35	#include <linux/config.h>
	36	#include <linux/init.h>
	37	#include <linux/slab.h>
	38	#include <linux/pci.h>
	39	#include <linux/delay.h>
	40	#include <linux/irq.h>
	41	#include <linux/proc_fs.h>
	42	#include <linux/random.h>
	43	#include <linux/kallsyms.h>
	44	#include <linux/profile.h>
	45	#include <linux/bitops.h>
	46
	47	#include <asm/uaccess.h>
	48	#include <asm/system.h>
	49	#include <asm/io.h>
	50	#include <asm/pgtable.h>
	51	#include <asm/irq.h>
	52	#include <asm/cache.h>
	53	#include <asm/prom.h>
	54	#include <asm/ptrace.h>
8875ccfb	55	#include <asm/iseries/it_lp_queue.h>
1da177e4 LT	56	#include <asm/machdep.h>
	57	#include <asm/paca.h>
	58
	59	#ifdef CONFIG_SMP
	60	extern void iSeries_smp_message_recv( struct pt_regs * );
	61	#endif
	62
	63	extern irq_desc_t irq_desc[NR_IRQS];
	64	EXPORT_SYMBOL(irq_desc);
	65
	66	int distribute_irqs = 1;
	67	int __irq_offset_value;
	68	int ppc_spurious_interrupts;
1da177e4 LT	69	u64 ppc64_interrupt_controller;
	70
	71	int show_interrupts(struct seq_file p, void v)
	72	{
	73	int i = (loff_t ) v, j;
	74	struct irqaction * action;
	75	irq_desc_t *desc;
	76	unsigned long flags;
	77
	78	if (i == 0) {
	79	seq_printf(p, " ");
	80	for (j=0; j<NR_CPUS; j++) {
	81	if (cpu_online(j))
	82	seq_printf(p, "CPU%d ",j);
	83	}
	84	seq_putc(p, '\n');
	85	}
	86
	87	if (i < NR_IRQS) {
	88	desc = get_irq_desc(i);
	89	spin_lock_irqsave(&desc->lock, flags);
	90	action = desc->action;
	91	if (!action \|\| !action->handler)
	92	goto skip;
	93	seq_printf(p, "%3d: ", i);
	94	#ifdef CONFIG_SMP
	95	for (j = 0; j < NR_CPUS; j++) {
	96	if (cpu_online(j))
	97	seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
	98	}
	99	#else
	100	seq_printf(p, "%10u ", kstat_irqs(i));
	101	#endif /* CONFIG_SMP */
	102	if (desc->handler)
	103	seq_printf(p, " %s ", desc->handler->typename );
	104	else
	105	seq_printf(p, " None ");
	106	seq_printf(p, "%s", (desc->status & IRQ_LEVEL) ? "Level " : "Edge ");
	107	seq_printf(p, " %s",action->name);
	108	for (action=action->next; action; action = action->next)
	109	seq_printf(p, ", %s", action->name);
	110	seq_putc(p, '\n');
	111	skip:
	112	spin_unlock_irqrestore(&desc->lock, flags);
	113	} else if (i == NR_IRQS)
	114	seq_printf(p, "BAD: %10u\n", ppc_spurious_interrupts);
	115	return 0;
	116	}
	117
	118	#ifdef CONFIG_HOTPLUG_CPU
	119	void fixup_irqs(cpumask_t map)
	120	{
	121	unsigned int irq;
	122	static int warned;
	123
	124	for_each_irq(irq) {
	125	cpumask_t mask;
	126
	127	if (irq_desc[irq].status & IRQ_PER_CPU)
	128	continue;
	129
	130	cpus_and(mask, irq_affinity[irq], map);
	131	if (any_online_cpu(mask) == NR_CPUS) {
	132	printk("Breaking affinity for irq %i\n", irq);
133	mask = map;
134	}
135	if (irq_desc[irq].handler->set_affinity)
136	irq_desc[irq].handler->set_affinity(irq, mask);
137	else if (irq_desc[irq].action && !(warned++))
138	printk("Cannot set affinity for irq %i\n", irq);
139	}
140
141	local_irq_enable();
142	mdelay(1);
143	local_irq_disable();
144	}
145	#endif
146
1da177e4 LT	147	#ifdef CONFIG_PPC_ISERIES
	148	void do_IRQ(struct pt_regs *regs)
	149	{
	150	struct paca_struct *lpaca;
1da177e4 LT	151
	152	irq_enter();
	153
	154	#ifdef CONFIG_DEBUG_STACKOVERFLOW
	155	/* Debugging check for stack overflow: is there less than 2KB free? */
	156	{
	157	long sp;
	158
	159	sp = __get_SP() & (THREAD_SIZE-1);
	160
	161	if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
	162	printk("do_IRQ: stack overflow: %ld\n",
	163	sp - sizeof(struct thread_info));
	164	dump_stack();
	165	}
	166	}
	167	#endif
	168
	169	lpaca = get_paca();
	170	#ifdef CONFIG_SMP
	171	if (lpaca->lppaca.int_dword.fields.ipi_cnt) {
	172	lpaca->lppaca.int_dword.fields.ipi_cnt = 0;
	173	iSeries_smp_message_recv(regs);
	174	}
	175	#endif /* CONFIG_SMP */
937b31b1	176	if (hvlpevent_is_pending())
74889802	177	process_hvlpevents(regs);
1da177e4 LT	178
	179	irq_exit();
	180
	181	if (lpaca->lppaca.int_dword.fields.decr_int) {
	182	lpaca->lppaca.int_dword.fields.decr_int = 0;
	183	/* Signal a fake decrementer interrupt */
	184	timer_interrupt(regs);
	185	}
	186	}
	187
	188	#else /* CONFIG_PPC_ISERIES */
	189
	190	void do_IRQ(struct pt_regs *regs)
	191	{
	192	int irq;
b709c083 SR	193	#ifdef CONFIG_IRQSTACKS
	194	struct thread_info curtp, irqtp;
	195	#endif
1da177e4 LT	196
	197	irq_enter();
	198
	199	#ifdef CONFIG_DEBUG_STACKOVERFLOW
	200	/* Debugging check for stack overflow: is there less than 2KB free? */
	201	{
	202	long sp;
	203
	204	sp = __get_SP() & (THREAD_SIZE-1);
	205
	206	if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
	207	printk("do_IRQ: stack overflow: %ld\n",
	208	sp - sizeof(struct thread_info));
	209	dump_stack();
	210	}
	211	}
	212	#endif
	213
	214	irq = ppc_md.get_irq(regs);
	215
b709c083 SR	216	if (irq >= 0) {
	217	#ifdef CONFIG_IRQSTACKS
	218	/* Switch to the irq stack to handle this */
	219	curtp = current_thread_info();
	220	irqtp = hardirq_ctx[smp_processor_id()];
	221	if (curtp != irqtp) {
	222	irqtp->task = curtp->task;
	223	irqtp->flags = 0;
d4be4f37	224	call___do_IRQ(irq, regs, irqtp);
b709c083 SR	225	irqtp->task = NULL;
	226	if (irqtp->flags)
	227	set_bits(irqtp->flags, &curtp->flags);
	228	} else
	229	#endif
d4be4f37	230	__do_IRQ(irq, regs);
b709c083	231	} else
1da177e4 LT	232	/* That's not SMP safe ... but who cares ? */
	233	ppc_spurious_interrupts++;
	234
	235	irq_exit();
	236	}
	237	#endif /* CONFIG_PPC_ISERIES */
	238
	239	void __init init_IRQ(void)
	240	{
	241	static int once = 0;
	242
	243	if (once)
	244	return;
	245
	246	once++;
	247
	248	ppc_md.init_IRQ();
	249	irq_ctx_init();
	250	}
	251
	252	#ifndef CONFIG_PPC_ISERIES
	253	/*
	254	* Virtual IRQ mapping code, used on systems with XICS interrupt controllers.
	255	*/
	256
	257	#define UNDEFINED_IRQ 0xffffffff
	258	unsigned int virt_irq_to_real_map[NR_IRQS];
	259
	260	/*
	261	* Don't use virtual irqs 0, 1, 2 for devices.
	262	* The pcnet32 driver considers interrupt numbers < 2 to be invalid,
	263	* and 2 is the XICS IPI interrupt.
	264	* We limit virtual irqs to 17 less than NR_IRQS so that when we
	265	* offset them by 16 (to reserve the first 16 for ISA interrupts)
	266	* we don't end up with an interrupt number >= NR_IRQS.
	267	*/
	268	#define MIN_VIRT_IRQ 3
	269	#define MAX_VIRT_IRQ (NR_IRQS - NUM_ISA_INTERRUPTS - 1)
	270	#define NR_VIRT_IRQS (MAX_VIRT_IRQ - MIN_VIRT_IRQ + 1)
	271
	272	void
	273	virt_irq_init(void)
	274	{
	275	int i;
	276	for (i = 0; i < NR_IRQS; i++)
	277	virt_irq_to_real_map[i] = UNDEFINED_IRQ;
	278	}
	279
	280	/* Create a mapping for a real_irq if it doesn't already exist.
	281	* Return the virtual irq as a convenience.
	282	*/
	283	int virt_irq_create_mapping(unsigned int real_irq)
	284	{
	285	unsigned int virq, first_virq;
	286	static int warned;
	287
	288	if (ppc64_interrupt_controller == IC_OPEN_PIC)
	289	return real_irq; /* no mapping for openpic (for now) */
	290
f3f66f59	291	if (ppc64_interrupt_controller == IC_CELL_PIC)
fef1c772 AB	292	return real_irq; /* no mapping for iic either */
fef1c772 AB	293
1da177e4 LT	294	/* don't map interrupts < MIN_VIRT_IRQ */
	295	if (real_irq < MIN_VIRT_IRQ) {
	296	virt_irq_to_real_map[real_irq] = real_irq;
	297	return real_irq;
	298	}
	299
	300	/* map to a number between MIN_VIRT_IRQ and MAX_VIRT_IRQ */
	301	virq = real_irq;
	302	if (virq > MAX_VIRT_IRQ)
	303	virq = (virq % NR_VIRT_IRQS) + MIN_VIRT_IRQ;
	304
	305	/* search for this number or a free slot */
	306	first_virq = virq;
	307	while (virt_irq_to_real_map[virq] != UNDEFINED_IRQ) {
	308	if (virt_irq_to_real_map[virq] == real_irq)
	309	return virq;
	310	if (++virq > MAX_VIRT_IRQ)
	311	virq = MIN_VIRT_IRQ;
	312	if (virq == first_virq)
	313	goto nospace; /* oops, no free slots */
	314	}
	315
	316	virt_irq_to_real_map[virq] = real_irq;
	317	return virq;
	318
	319	nospace:
	320	if (!warned) {
	321	printk(KERN_CRIT "Interrupt table is full\n");
	322	printk(KERN_CRIT "Increase NR_IRQS (currently %d) "
	323	"in your kernel sources and rebuild.\n", NR_IRQS);
	324	warned = 1;
	325	}
	326	return NO_IRQ;
	327	}
	328
	329	/*
	330	* In most cases will get a hit on the very first slot checked in the
	331	* virt_irq_to_real_map. Only when there are a large number of
	332	* IRQs will this be expensive.
	333	*/
	334	unsigned int real_irq_to_virt_slowpath(unsigned int real_irq)
	335	{
	336	unsigned int virq;
	337	unsigned int first_virq;
	338
	339	virq = real_irq;
	340
	341	if (virq > MAX_VIRT_IRQ)
	342	virq = (virq % NR_VIRT_IRQS) + MIN_VIRT_IRQ;
	343
	344	first_virq = virq;
	345
	346	do {
	347	if (virt_irq_to_real_map[virq] == real_irq)
	348	return virq;
	349
	350	virq++;
	351
	352	if (virq >= MAX_VIRT_IRQ)
	353	virq = 0;
	354
	355	} while (first_virq != virq);
	356
	357	return NO_IRQ;
358
359	}
360
361	#endif /* CONFIG_PPC_ISERIES */
362
363	#ifdef CONFIG_IRQSTACKS
364	struct thread_info *softirq_ctx[NR_CPUS];
365	struct thread_info *hardirq_ctx[NR_CPUS];
366
367	void irq_ctx_init(void)
368	{
369	struct thread_info *tp;
370	int i;
371
372	for_each_cpu(i) {
373	memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
374	tp = softirq_ctx[i];
375	tp->cpu = i;
376	tp->preempt_count = SOFTIRQ_OFFSET;
377
378	memset((void *)hardirq_ctx[i], 0, THREAD_SIZE);
379	tp = hardirq_ctx[i];
380	tp->cpu = i;
381	tp->preempt_count = HARDIRQ_OFFSET;
382	}
383	}
384
385	void do_softirq(void)
386	{
387	unsigned long flags;
388	struct thread_info curtp, irqtp;
389
390	if (in_interrupt())
391	return;
392
393	local_irq_save(flags);
394
395	if (local_softirq_pending()) {
396	curtp = current_thread_info();
397	irqtp = softirq_ctx[smp_processor_id()];
398	irqtp->task = curtp->task;
399	call_do_softirq(irqtp);
400	irqtp->task = NULL;
401	}
402
403	local_irq_restore(flags);
404	}
405	EXPORT_SYMBOL(do_softirq);
406
407	#endif /* CONFIG_IRQSTACKS */
408
409	static int __init setup_noirqdistrib(char *str)
410	{
411	distribute_irqs = 0;
412	return 1;
413	}
414
415	__setup("noirqdistrib", setup_noirqdistrib);