[deliverable/linux.git] / arch / x86 / kernel / irq_32.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_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
EXPORT_PER_CPU_SYMBOL(irq_stat);

DEFINE_PER_CPU(struct pt_regs *, irq_regs);
EXPORT_PER_CPU_SYMBOL(irq_regs);

/*
 * '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	1	/*
1da177e4 LT	2	* Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
	3	*
	4	* This file contains the lowest level x86-specific interrupt
	5	* entry, irq-stacks and irq statistics code. All the remaining
	6	* irq logic is done by the generic kernel/irq/ code and
	7	* by the x86-specific irq controller code. (e.g. i8259.c and
	8	* io_apic.c.)
	9	*/
	10
1da177e4 LT	11	#include <linux/module.h>
	12	#include <linux/seq_file.h>
	13	#include <linux/interrupt.h>
	14	#include <linux/kernel_stat.h>
f3705136 ZM	15	#include <linux/notifier.h>
	16	#include <linux/cpu.h>
	17	#include <linux/delay.h>
1da177e4	18
e05d723f TG	19	#include <asm/apic.h>
	20	#include <asm/uaccess.h>
	21
f34e3b61	22	DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
1da177e4 LT	23	EXPORT_PER_CPU_SYMBOL(irq_stat);
1da177e4 LT	24
7c3576d2 JF	25	DEFINE_PER_CPU(struct pt_regs *, irq_regs);
	26	EXPORT_PER_CPU_SYMBOL(irq_regs);
	27
1da177e4 LT	28	/*
	29	* 'what should we do if we get a hw irq event on an illegal vector'.
	30	* each architecture has to answer this themselves.
	31	*/
	32	void ack_bad_irq(unsigned int irq)
	33	{
e05d723f TG	34	printk(KERN_ERR "unexpected IRQ trap at vector %02x\n", irq);
	35
	36	#ifdef CONFIG_X86_LOCAL_APIC
	37	/*
	38	* Currently unexpected vectors happen only on SMP and APIC.
	39	* We _must_ ack these because every local APIC has only N
	40	* irq slots per priority level, and a 'hanging, unacked' IRQ
	41	* holds up an irq slot - in excessive cases (when multiple
	42	* unexpected vectors occur) that might lock up the APIC
	43	* completely.
	44	* But only ack when the APIC is enabled -AK
	45	*/
	46	if (cpu_has_apic)
	47	ack_APIC_irq();
1da177e4	48	#endif
e05d723f	49	}
1da177e4 LT	50
	51	#ifdef CONFIG_4KSTACKS
	52	/*
	53	* per-CPU IRQ handling contexts (thread information and stack)
	54	*/
	55	union irq_ctx {
	56	struct thread_info tinfo;
	57	u32 stack[THREAD_SIZE/sizeof(u32)];
	58	};
	59
22722051 AM	60	static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
22722051 AM	61	static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
1da177e4 LT	62	#endif
	63
	64	/*
	65	* do_IRQ handles all normal device IRQ's (the special
	66	* SMP cross-CPU interrupts have their own specific
	67	* handlers).
	68	*/
	69	fastcall unsigned int do_IRQ(struct pt_regs *regs)
	70	{
7d12e780	71	struct pt_regs *old_regs;
19eadf98 RR	72	/* high bit used in ret_from_ code */
19eadf98 RR	73	int irq = ~regs->orig_eax;
f5b9ed7a	74	struct irq_desc *desc = irq_desc + irq;
1da177e4 LT	75	#ifdef CONFIG_4KSTACKS
	76	union irq_ctx curctx, irqctx;
	77	u32 *isp;
	78	#endif
	79
a052b68b AM	80	if (unlikely((unsigned)irq >= NR_IRQS)) {
	81	printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
	82	__FUNCTION__, irq);
	83	BUG();
	84	}
	85
7d12e780	86	old_regs = set_irq_regs(regs);
1da177e4 LT	87	irq_enter();
	88	#ifdef CONFIG_DEBUG_STACKOVERFLOW
	89	/* Debugging check for stack overflow: is there less than 1KB free? */
	90	{
	91	long esp;
	92
	93	__asm__ __volatile__("andl %%esp,%0" :
	94	"=r" (esp) : "0" (THREAD_SIZE - 1));
	95	if (unlikely(esp < (sizeof(struct thread_info) + STACK_WARN))) {
	96	printk("do_IRQ: stack overflow: %ld\n",
	97	esp - sizeof(struct thread_info));
	98	dump_stack();
	99	}
	100	}
	101	#endif
	102
	103	#ifdef CONFIG_4KSTACKS
	104
	105	curctx = (union irq_ctx *) current_thread_info();
	106	irqctx = hardirq_ctx[smp_processor_id()];
	107
	108	/*
	109	* this is where we switch to the IRQ stack. However, if we are
	110	* already using the IRQ stack (because we interrupted a hardirq
	111	* handler) we can't do that and just have to keep using the
	112	* current stack (which is the irq stack already after all)
	113	*/
	114	if (curctx != irqctx) {
7d12e780	115	int arg1, arg2, ebx;
1da177e4 LT	116
	117	/* build the stack frame on the IRQ stack */
	118	isp = (u32) ((char)irqctx + sizeof(*irqctx));
	119	irqctx->tinfo.task = curctx->tinfo.task;
	120	irqctx->tinfo.previous_esp = current_stack_pointer;
	121