[deliverable/linux.git] / arch / i386 / kernel / irq.c

/*
 *	linux/arch/i386/kernel/irq.c
 *
 *	Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
 *
 * This file contains the lowest level x86-specific interrupt
 * entry, irq-stacks and irq statistics code. All the remaining
 * irq logic is done by the generic kernel/irq/ code and
 * by the x86-specific irq controller code. (e.g. i8259.c and
 * io_apic.c.)
 */

#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/notifier.h>
#include <linux/cpu.h>
#include <linux/delay.h>

#include <asm/apic.h>
#include <asm/uaccess.h>

DEFINE_PER_CPU(irq_cpustat_t, irq_stat) ____cacheline_internodealigned_in_smp;
EXPORT_PER_CPU_SYMBOL(irq_stat);

/*
 * 'what should we do if we get a hw irq event on an illegal vector'.
 * each architecture has to answer this themselves.
 */
void ack_bad_irq(unsigned int irq)
{
	printk(KERN_ERR "unexpected IRQ trap at vector %02x\n", irq);

#ifdef CONFIG_X86_LOCAL_APIC
	/*
	 * Currently unexpected vectors happen only on SMP and APIC.
	 * We _must_ ack these because every local APIC has only N
	 * irq slots per priority level, and a 'hanging, unacked' IRQ
	 * holds up an irq slot - in excessive cases (when multiple
	 * unexpected vectors occur) that might lock up the APIC
	 * completely.
	 * But only ack when the APIC is enabled -AK
	 */
	if (cpu_has_apic)
		ack_APIC_irq();
#endif
}

#ifdef CONFIG_4KSTACKS
/*
 * per-CPU IRQ handling contexts (thread information and stack)
 */
union irq_ctx {
	struct thread_info      tinfo;
	u32                     stack[THREAD_SIZE/sizeof(u32)];
};

static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
#endif

/*
 * do_IRQ handles all normal device IRQ's (the special
 * SMP cross-CPU interrupts have their own specific
 * handlers).
 */
fastcall unsigned int do_IRQ(struct pt_regs *regs)
{	
	struct pt_regs *old_regs;
	/* high bit used in ret_from_ code */
	int irq = ~regs->orig_eax;
	struct irq_desc *desc = irq_desc + irq;
#ifdef CONFIG_4KSTACKS
	union irq_ctx *curctx, *irqctx;
	u32 *isp;
#endif

	if (unlikely((unsigned)irq >= NR_IRQS)) {
		printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
					__FUNCTION__, irq);
		BUG();
	}

	old_regs = set_irq_regs(regs);
	irq_enter();
#ifdef CONFIG_DEBUG_STACKOVERFLOW
	/* Debugging check for stack overflow: is there less than 1KB free? */
	{
		long esp;

		__asm__ __volatile__("andl %%esp,%0" :
					"=r" (esp) : "0" (THREAD_SIZE - 1));
		if (unlikely(esp < (sizeof(struct thread_info) + STACK_WARN))) {
			printk("do_IRQ: stack overflow: %ld\n",
				esp - sizeof(struct thread_info));
			dump_stack();
		}
	}
#endif

#ifdef CONFIG_4KSTACKS

	curctx = (union irq_ctx *) current_thread_info();
	irqctx = hardirq_ctx[smp_processor_id()];

	/*
	 * this is where we switch to the IRQ stack. However, if we are
	 * already using the IRQ stack (because we interrupted a hardirq
	 * handler) we can't do that and just have to keep using the
	 * current stack (which is the irq stack already after all)
	 */
	if (curctx != irqctx) {
		int arg1, arg2, ebx;

		/* build the stack frame on the IRQ stack */
		isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
		irqctx->tinfo.task = curctx->tinfo.task;
		irqctx->tinfo.previous_esp = current_stack_pointer;
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/arch/i386/kernel/irq.c
	3	*
	4	* Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
	5	*
	6	* This file contains the lowest level x86-specific interrupt
	7	* entry, irq-stacks and irq statistics code. All the remaining
	8	* irq logic is done by the generic kernel/irq/ code and
	9	* by the x86-specific irq controller code. (e.g. i8259.c and
	10	* io_apic.c.)
	11	*/
	12
1da177e4 LT	13	#include <linux/module.h>
	14	#include <linux/seq_file.h>
	15	#include <linux/interrupt.h>
	16	#include <linux/kernel_stat.h>
f3705136 ZM	17	#include <linux/notifier.h>
	18	#include <linux/cpu.h>
	19	#include <linux/delay.h>
1da177e4	20
e05d723f TG	21	#include <asm/apic.h>
	22	#include <asm/uaccess.h>
	23
22fc6ecc	24	DEFINE_PER_CPU(irq_cpustat_t, irq_stat) ____cacheline_internodealigned_in_smp;
1da177e4 LT	25	EXPORT_PER_CPU_SYMBOL(irq_stat);
1da177e4 LT	26
1da177e4 LT	27	/*
	28	* 'what should we do if we get a hw irq event on an illegal vector'.
	29	* each architecture has to answer this themselves.
	30	*/
	31	void ack_bad_irq(unsigned int irq)
	32	{
e05d723f TG	33	printk(KERN_ERR "unexpected IRQ trap at vector %02x\n", irq);
	34
	35	#ifdef CONFIG_X86_LOCAL_APIC
	36	/*
	37	* Currently unexpected vectors happen only on SMP and APIC.
	38	* We _must_ ack these because every local APIC has only N
	39	* irq slots per priority level, and a 'hanging, unacked' IRQ
	40	* holds up an irq slot - in excessive cases (when multiple
	41	* unexpected vectors occur) that might lock up the APIC
	42	* completely.
	43	* But only ack when the APIC is enabled -AK
	44	*/
	45	if (cpu_has_apic)
	46	ack_APIC_irq();
1da177e4	47	#endif
e05d723f	48	}
1da177e4 LT	49
	50	#ifdef CONFIG_4KSTACKS
	51	/*
	52	* per-CPU IRQ handling contexts (thread information and stack)
	53	*/
	54	union irq_ctx {
	55	struct thread_info tinfo;
	56	u32 stack[THREAD_SIZE/sizeof(u32)];
	57	};
	58
22722051 AM	59	static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
22722051 AM	60	static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
1da177e4 LT	61	#endif
	62
	63	/*
	64	* do_IRQ handles all normal device IRQ's (the special
	65	* SMP cross-CPU interrupts have their own specific
	66	* handlers).
	67	*/
	68	fastcall unsigned int do_IRQ(struct pt_regs *regs)
	69	{
7d12e780	70	struct pt_regs *old_regs;
19eadf98 RR	71	/* high bit used in ret_from_ code */
19eadf98 RR	72	int irq = ~regs->orig_eax;
f5b9ed7a	73	struct irq_desc *desc = irq_desc + irq;
1da177e4 LT	74	#ifdef CONFIG_4KSTACKS
	75	union irq_ctx curctx, irqctx;
	76	u32 *isp;
	77	#endif
	78
a052b68b AM	79	if (unlikely((unsigned)irq >= NR_IRQS)) {
	80	printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
	81	__FUNCTION__, irq);
	82	BUG();
	83	}
	84
7d12e780	85	old_regs = set_irq_regs(regs);
1da177e4 LT	86	irq_enter();
	87	#ifdef CONFIG_DEBUG_STACKOVERFLOW
	88	/* Debugging check for stack overflow: is there less than 1KB free? */
	89	{
	90	long esp;
	91
	92	__asm__ __volatile__("andl %%esp,%0" :
	93	"=r" (esp) : "0" (THREAD_SIZE - 1));
	94	if (unlikely(esp < (sizeof(struct thread_info) + STACK_WARN))) {
	95	printk("do_IRQ: stack overflow: %ld\n",
	96	esp - sizeof(struct thread_info));
	97	dump_stack();
	98	}
	99	}
	100	#endif
	101
	102	#ifdef CONFIG_4KSTACKS
	103
	104	curctx = (union irq_ctx *) current_thread_info();
	105	irqctx = hardirq_ctx[smp_processor_id()];
	106
	107	/*
	108	* this is where we switch to the IRQ stack. However, if we are
	109	* already using the IRQ stack (because we interrupted a hardirq
	110	* handler) we can't do that and just have to keep using the
	111	* current stack (which is the irq stack already after all)
	112	*/
	113	if (curctx != irqctx) {
7d12e780	114	int arg1, arg2, ebx;
1da177e4 LT	115
	116	/* build the stack frame on the IRQ stack */
	117	isp = (u32) ((char)irqctx + sizeof(*irqctx));
	118	irqctx->tinfo.task = curctx->tinfo.task;
	119	irqctx->tinfo.previous_esp = current_stack_pointer;
	120