[patch 2/5, 2.6.9-rc3] generic irq subsystem, x86 port

From: Ingo Molnar
Date: Fri Oct 01 2004 - 16:12:14 EST


x86 port of generic hardirq handling.

Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>

--- linux/arch/i386/Kconfig.orig
+++ linux/arch/i386/Kconfig
@@ -1194,6 +1194,13 @@ source "crypto/Kconfig"

source "lib/Kconfig"

+#
+# Use the generic interrupt handling code in kernel/hardirq.c:
+#
+config GENERIC_HARDIRQS
+ bool
+ default y
+
config X86_SMP
bool
depends on SMP && !X86_VOYAGER
--- linux/arch/i386/kernel/vm86.c.orig
+++ linux/arch/i386/kernel/vm86.c
@@ -741,7 +741,7 @@ static inline void free_vm86_irq(int irq
spin_unlock_irqrestore(&irqbits_lock, flags);
}

-void release_x86_irqs(struct task_struct *task)
+void release_vm86_irqs(struct task_struct *task)
{
int i;
for (i = FIRST_VM86_IRQ ; i <= LAST_VM86_IRQ; i++)
--- linux/arch/i386/kernel/io_apic.c.orig
+++ linux/arch/i386/kernel/io_apic.c
@@ -255,8 +255,6 @@ static void set_ioapic_affinity_irq(unsi
# define Dprintk(x...)
# endif

-extern cpumask_t irq_affinity[NR_IRQS];
-
cpumask_t __cacheline_aligned pending_irq_balance_cpumask[NR_IRQS];

#define IRQBALANCE_CHECK_ARCH -999
--- linux/arch/i386/kernel/i386_ksyms.c.orig
+++ linux/arch/i386/kernel/i386_ksyms.c
@@ -76,9 +76,6 @@ EXPORT_SYMBOL_GPL(kernel_fpu_begin);
EXPORT_SYMBOL(__ioremap);
EXPORT_SYMBOL(ioremap_nocache);
EXPORT_SYMBOL(iounmap);
-EXPORT_SYMBOL(enable_irq);
-EXPORT_SYMBOL(disable_irq);
-EXPORT_SYMBOL(disable_irq_nosync);
EXPORT_SYMBOL(probe_irq_mask);
EXPORT_SYMBOL(kernel_thread);
EXPORT_SYMBOL(pm_idle);
@@ -146,7 +143,6 @@ EXPORT_SYMBOL(__write_lock_failed);
EXPORT_SYMBOL(__read_lock_failed);

/* Global SMP stuff */
-EXPORT_SYMBOL(synchronize_irq);
EXPORT_SYMBOL(smp_call_function);

/* TLB flushing */
--- linux/arch/i386/kernel/process.c.orig
+++ linux/arch/i386/kernel/process.c
@@ -344,7 +344,7 @@ void release_thread(struct task_struct *
}
}

- release_x86_irqs(dead_task);
+ release_vm86_irqs(dead_task);
}

/*
--- linux/arch/i386/kernel/irq.c.orig
+++ linux/arch/i386/kernel/irq.c
@@ -3,437 +3,47 @@
*
* Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
*
- * 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.
+ * 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.)
*/

-/*
- * (mostly architecture independent, will move to kernel/irq.c in 2.5.)
- *
- * IRQs are in fact implemented a bit like signal handlers for the kernel.
- * Naturally it's not a 1:1 relation, but there are similarities.
- */
-
-#include <linux/config.h>
-#include <linux/errno.h>
+#include <asm/uaccess.h>
#include <linux/module.h>
-#include <linux/signal.h>
-#include <linux/sched.h>
-#include <linux/ioport.h>
+#include <linux/seq_file.h>
#include <linux/interrupt.h>
-#include <linux/timex.h>
-#include <linux/slab.h>
-#include <linux/random.h>
-#include <linux/smp_lock.h>
-#include <linux/init.h>
#include <linux/kernel_stat.h>
-#include <linux/irq.h>
-#include <linux/proc_fs.h>
-#include <linux/seq_file.h>
-#include <linux/kallsyms.h>
-
-#include <asm/atomic.h>
-#include <asm/io.h>
-#include <asm/smp.h>
-#include <asm/system.h>
-#include <asm/bitops.h>
-#include <asm/uaccess.h>
-#include <asm/delay.h>
-#include <asm/desc.h>
-#include <asm/irq.h>
-
-/*
- * Linux has a controller-independent x86 interrupt architecture.
- * every controller has a 'controller-template', that is used
- * by the main code to do the right thing. Each driver-visible
- * interrupt source is transparently wired to the apropriate
- * controller. Thus drivers need not be aware of the
- * interrupt-controller.
- *
- * Various interrupt controllers we handle: 8259 PIC, SMP IO-APIC,
- * PIIX4's internal 8259 PIC and SGI's Visual Workstation Cobalt (IO-)APIC.
- * (IO-APICs assumed to be messaging to Pentium local-APICs)
- *
- * the code is designed to be easily extended with new/different
- * interrupt controllers, without having to do assembly magic.
- */

-/*
- * Controller mappings for all interrupt sources:
- */
-irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned = {
- [0 ... NR_IRQS-1] = {
- .handler = &no_irq_type,
- .lock = SPIN_LOCK_UNLOCKED
- }
-};
-
-static void register_irq_proc (unsigned int irq);
-
-/*
- * per-CPU IRQ handling stacks
- */
#ifdef CONFIG_4KSTACKS
-union irq_ctx *hardirq_ctx[NR_CPUS];
-union irq_ctx *softirq_ctx[NR_CPUS];
-#endif
-
-/*
- * Special irq handlers.
- */
-
-irqreturn_t no_action(int cpl, void *dev_id, struct pt_regs *regs)
-{ return IRQ_NONE; }
-
/*
- * Generic no controller code
+ * per-CPU IRQ handling contexts (thread information and stack)
*/
-
-static void enable_none(unsigned int irq) { }
-static unsigned int startup_none(unsigned int irq) { return 0; }
-static void disable_none(unsigned int irq) { }
-static void ack_none(unsigned int irq)
-{
-/*
- * 'what should we do if we get a hw irq event on an illegal vector'.
- * each architecture has to answer this themselves, it doesn't deserve
- * a generic callback i think.
- */
-#ifdef CONFIG_X86
- printk("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.
- */
- ack_APIC_irq();
-#endif
-#endif
-}
-
-/* startup is the same as "enable", shutdown is same as "disable" */
-#define shutdown_none disable_none
-#define end_none enable_none
-
-struct hw_interrupt_type no_irq_type = {
- "none",
- startup_none,
- shutdown_none,
- enable_none,
- disable_none,
- ack_none,
- end_none
+union irq_ctx {
+ struct thread_info tinfo;
+ u32 stack[THREAD_SIZE/sizeof(u32)];
};

-atomic_t irq_err_count;
-#if defined(CONFIG_X86_IO_APIC) && defined(APIC_MISMATCH_DEBUG)
-atomic_t irq_mis_count;
-#endif
-
-/*
- * Generic, controller-independent functions:
- */
-
-int show_interrupts(struct seq_file *p, void *v)
-{
- int i = *(loff_t *) v, j;
- struct irqaction * action;
- 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) {
- spin_lock_irqsave(&irq_desc[i].lock, flags);
- action = irq_desc[i].action;
- if (!action)
- goto skip;
- seq_printf(p, "%3d: ",i);
-#ifndef CONFIG_SMP
- seq_printf(p, "%10u ", kstat_irqs(i));
-#else
- for (j = 0; j < NR_CPUS; j++)
- if (cpu_online(j))
- seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
-#endif
- seq_printf(p, " %14s", irq_desc[i].handler->typename);
- 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(&irq_desc[i].lock, flags);
- } else if (i == NR_IRQS) {
- seq_printf(p, "NMI: ");
- for (j = 0; j < NR_CPUS; j++)
- if (cpu_online(j))
- seq_printf(p, "%10u ", nmi_count(j));
- seq_putc(p, '\n');
-#ifdef CONFIG_X86_LOCAL_APIC
- seq_printf(p, "LOC: ");
- for (j = 0; j < NR_CPUS; j++)
- if (cpu_online(j))
- seq_printf(p, "%10u ", irq_stat[j].apic_timer_irqs);
- seq_putc(p, '\n');
-#endif
- seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
-#if defined(CONFIG_X86_IO_APIC) && defined(APIC_MISMATCH_DEBUG)
- seq_printf(p, "MIS: %10u\n", atomic_read(&irq_mis_count));
-#endif
- }
- return 0;
-}
-
-
-
-
-#ifdef CONFIG_SMP
-inline void synchronize_irq(unsigned int irq)
-{
- while (irq_desc[irq].status & IRQ_INPROGRESS)
- cpu_relax();
-}
+static union irq_ctx *hardirq_ctx[NR_CPUS];
+static union irq_ctx *softirq_ctx[NR_CPUS];
#endif

/*
- * This should really return information about whether
- * we should do bottom half handling etc. Right now we
- * end up _always_ checking the bottom half, which is a
- * waste of time and is not what some drivers would
- * prefer.
- */
-asmlinkage int handle_IRQ_event(unsigned int irq,
- struct pt_regs *regs, struct irqaction *action)
-{
- int status = 1; /* Force the "do bottom halves" bit */
- int ret, retval = 0;
-
- if (!(action->flags & SA_INTERRUPT))
- local_irq_enable();
-
- do {
- ret = action->handler(irq, action->dev_id, regs);
- if (ret == IRQ_HANDLED)
- status |= action->flags;
- retval |= ret;
- action = action->next;
- } while (action);
- if (status & SA_SAMPLE_RANDOM)
- add_interrupt_randomness(irq);
- local_irq_disable();
- return retval;
-}
-
-static void __report_bad_irq(int irq, irq_desc_t *desc, irqreturn_t action_ret)
-{
- struct irqaction *action;
-
- if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
- printk(KERN_ERR "irq event %d: bogus return value %x\n",
- irq, action_ret);
- } else {
- printk(KERN_ERR "irq %d: nobody cared!\n", irq);
- }
- dump_stack();
- printk(KERN_ERR "handlers:\n");
- action = desc->action;
- do {
- printk(KERN_ERR "[<%p>]", action->handler);
- print_symbol(" (%s)",
- (unsigned long)action->handler);
- printk("\n");
- action = action->next;
- } while (action);
-}
-
-static void report_bad_irq(int irq, irq_desc_t *desc, irqreturn_t action_ret)
-{
- static int count = 100;
-
- if (count) {
- count--;
- __report_bad_irq(irq, desc, action_ret);
- }
-}
-
-static int noirqdebug;
-
-static int __init noirqdebug_setup(char *str)
-{
- noirqdebug = 1;
- printk("IRQ lockup detection disabled\n");
- return 1;
-}
-
-__setup("noirqdebug", noirqdebug_setup);
-
-/*
- * If 99,900 of the previous 100,000 interrupts have not been handled then
- * assume that the IRQ is stuck in some manner. Drop a diagnostic and try to
- * turn the IRQ off.
- *
- * (The other 100-of-100,000 interrupts may have been a correctly-functioning
- * device sharing an IRQ with the failing one)
- *
- * Called under desc->lock
- */
-static void note_interrupt(int irq, irq_desc_t *desc, irqreturn_t action_ret)
-{
- if (action_ret != IRQ_HANDLED) {
- desc->irqs_unhandled++;
- if (action_ret != IRQ_NONE)
- report_bad_irq(irq, desc, action_ret);
- }
-
- desc->irq_count++;
- if (desc->irq_count < 100000)
- return;
-
- desc->irq_count = 0;
- if (desc->irqs_unhandled > 99900) {
- /*
- * The interrupt is stuck
- */
- __report_bad_irq(irq, desc, action_ret);
- /*
- * Now kill the IRQ
- */
- printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
- desc->status |= IRQ_DISABLED;
- desc->handler->disable(irq);
- }
- desc->irqs_unhandled = 0;
-}
-
-/*
- * Generic enable/disable code: this just calls
- * down into the PIC-specific version for the actual
- * hardware disable after having gotten the irq
- * controller lock.
- */
-
-/**
- * disable_irq_nosync - disable an irq without waiting
- * @irq: Interrupt to disable
- *
- * Disable the selected interrupt line. Disables and Enables are
- * nested.
- * Unlike disable_irq(), this function does not ensure existing
- * instances of the IRQ handler have completed before returning.
- *
- * This function may be called from IRQ context.
- */
-
-inline void disable_irq_nosync(unsigned int irq)
-{
- irq_desc_t *desc = irq_desc + irq;
- unsigned long flags;
-
- spin_lock_irqsave(&desc->lock, flags);
- if (!desc->depth++) {
- desc->status |= IRQ_DISABLED;
- desc->handler->disable(irq);
- }
- spin_unlock_irqrestore(&desc->lock, flags);
-}
-
-/**
- * disable_irq - disable an irq and wait for completion
- * @irq: Interrupt to disable
- *
- * Disable the selected interrupt line. Enables and Disables are
- * nested.
- * This function waits for any pending IRQ handlers for this interrupt
- * to complete before returning. If you use this function while
- * holding a resource the IRQ handler may need you will deadlock.
- *
- * This function may be called - with care - from IRQ context.
- */
-
-void disable_irq(unsigned int irq)
-{
- irq_desc_t *desc = irq_desc + irq;
- disable_irq_nosync(irq);
- if (desc->action)
- synchronize_irq(irq);
-}
-
-/**
- * enable_irq - enable handling of an irq
- * @irq: Interrupt to enable
- *
- * Undoes the effect of one call to disable_irq(). If this
- * matches the last disable, processing of interrupts on this
- * IRQ line is re-enabled.
- *
- * This function may be called from IRQ context.
- */
-
-void enable_irq(unsigned int irq)
-{
- irq_desc_t *desc = irq_desc + irq;
- unsigned long flags;
-
- spin_lock_irqsave(&desc->lock, flags);
- switch (desc->depth) {
- case 1: {
- unsigned int status = desc->status & ~IRQ_DISABLED;
- desc->status = status;
- if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) {
- desc->status = status | IRQ_REPLAY;
- hw_resend_irq(desc->handler,irq);
- }
- desc->handler->enable(irq);
- /* fall-through */
- }
- default:
- desc->depth--;
- break;
- case 0:
- printk("enable_irq(%u) unbalanced from %p\n", irq,
- __builtin_return_address(0));
- }
- spin_unlock_irqrestore(&desc->lock, flags);
-}
-
-/*
* do_IRQ handles all normal device IRQ's (the special
* SMP cross-CPU interrupts have their own specific
* handlers).
*/
asmlinkage unsigned int do_IRQ(struct pt_regs regs)
{
- /*
- * We ack quickly, we don't want the irq controller
- * thinking we're snobs just because some other CPU has
- * disabled global interrupts (we have already done the
- * INT_ACK cycles, it's too late to try to pretend to the
- * controller that we aren't taking the interrupt).
- *
- * 0 return value means that this irq is already being
- * handled by some other CPU. (or is disabled)
- */
- int irq = regs.orig_eax & 0xff; /* high bits used in ret_from_ code */
- irq_desc_t *desc = irq_desc + irq;
- struct irqaction * action;
- unsigned int status;
+ /* high bits used in ret_from_ code */
+ int irq = regs.orig_eax & 0xff;
+#ifdef CONFIG_4KSTACKS
+ union irq_ctx *curctx, *irqctx;
+ u32 *isp;
+#endif

irq_enter();
-
#ifdef CONFIG_DEBUG_STACKOVERFLOW
/* Debugging check for stack overflow: is there less than 1KB free? */
{
@@ -448,642 +58,54 @@ asmlinkage unsigned int do_IRQ(struct pt
}
}
#endif
- kstat_this_cpu.irqs[irq]++;
- spin_lock(&desc->lock);
- desc->handler->ack(irq);
- /*
- REPLAY is when Linux resends an IRQ that was dropped earlier
- WAITING is used by probe to mark irqs that are being tested
- */
- status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
- status |= IRQ_PENDING; /* we _want_ to handle it */

- /*
- * If the IRQ is disabled for whatever reason, we cannot
- * use the action we have.
- */
- action = NULL;
- if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
- action = desc->action;
- status &= ~IRQ_PENDING; /* we commit to handling */
- status |= IRQ_INPROGRESS; /* we are handling it */
- }
- desc->status = status;
+#ifdef CONFIG_4KSTACKS

- /*
- * If there is no IRQ handler or it was disabled, exit early.
- Since we set PENDING, if another processor is handling
- a different instance of this same irq, the other processor
- will take care of it.
- */
- if (unlikely(!action))
- goto out;
+ curctx = (union irq_ctx *) current_thread_info();
+ irqctx = hardirq_ctx[smp_processor_id()];

/*
- * Edge triggered interrupts need to remember
- * pending events.
- * This applies to any hw interrupts that allow a second
- * instance of the same irq to arrive while we are in do_IRQ
- * or in the handler. But the code here only handles the _second_
- * instance of the irq, not the third or fourth. So it is mostly
- * useful for irq hardware that does not mask cleanly in an
- * SMP environment.
+ * 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)
*/
-#ifdef CONFIG_4KSTACKS
-
- for (;;) {
- irqreturn_t action_ret;
- u32 *isp;
- union irq_ctx * curctx;
- union irq_ctx * irqctx;
-
- curctx = (union irq_ctx *) current_thread_info();
- irqctx = hardirq_ctx[smp_processor_id()];
-
- spin_unlock(&desc->lock);
-
- /*
- * 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)
- action_ret = handle_IRQ_event(irq, &regs, action);
- else {
- /* 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();
-
- *--isp = (u32) action;
- *--isp = (u32) &regs;
- *--isp = (u32) irq;
-
- asm volatile(
- " xchgl %%ebx,%%esp \n"
- " call handle_IRQ_event \n"
- " xchgl %%ebx,%%esp \n"
- : "=a"(action_ret)
- : "b"(isp)
- : "memory", "cc", "edx", "ecx"
- );
-
-
- }
- spin_lock(&desc->lock);
- if (!noirqdebug)
- note_interrupt(irq, desc, action_ret);
- if (curctx != irqctx)
- irqctx->tinfo.task = NULL;
- if (likely(!(desc->status & IRQ_PENDING)))
- break;
- desc->status &= ~IRQ_PENDING;
- }
-
-#else
-
- for (;;) {
- irqreturn_t action_ret;
-
- spin_unlock(&desc->lock);
+ if (curctx != irqctx) {
+ /* 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();

- action_ret = handle_IRQ_event(irq, &regs, action);
+ *--isp = (u32) &regs;
+ *--isp = (u32) irq;

- spin_lock(&desc->lock);
- if (!noirqdebug)
- note_interrupt(irq, desc, action_ret);
- if (likely(!(desc->status & IRQ_PENDING)))
- break;
- desc->status &= ~IRQ_PENDING;
- }
+ asm volatile(
+ " xchgl %%ebx,%%esp \n"
+ " call __do_IRQ \n"
+ " xchgl %%ebx,%%esp \n"
+ : : "b"(isp)
+ : "memory", "cc", "eax", "edx", "ecx"
+ );
+ } else
#endif
- desc->status &= ~IRQ_INPROGRESS;
-
-out:
- /*
- * The ->end() handler has to deal with interrupts which got
- * disabled while the handler was running.
- */
- desc->handler->end(irq);
- spin_unlock(&desc->lock);
+ __do_IRQ(irq, &regs);

irq_exit();

return 1;
}

-int can_request_irq(unsigned int irq, unsigned long irqflags)
-{
- struct irqaction *action;
-
- if (irq >= NR_IRQS)
- return 0;
- action = irq_desc[irq].action;
- if (action) {
- if (irqflags & action->flags & SA_SHIRQ)
- action = NULL;
- }
- return !action;
-}
-
-/**
- * request_irq - allocate an interrupt line
- * @irq: Interrupt line to allocate
- * @handler: Function to be called when the IRQ occurs
- * @irqflags: Interrupt type flags
- * @devname: An ascii name for the claiming device
- * @dev_id: A cookie passed back to the handler function
- *
- * This call allocates interrupt resources and enables the
- * interrupt line and IRQ handling. From the point this
- * call is made your handler function may be invoked. Since
- * your handler function must clear any interrupt the board
- * raises, you must take care both to initialise your hardware
- * and to set up the interrupt handler in the right order.
- *
- * Dev_id must be globally unique. Normally the address of the
- * device data structure is used as the cookie. Since the handler
- * receives this value it makes sense to use it.
- *
- * If your interrupt is shared you must pass a non NULL dev_id
- * as this is required when freeing the interrupt.
- *
- * Flags:
- *
- * SA_SHIRQ Interrupt is shared
- *
- * SA_INTERRUPT Disable local interrupts while processing
- *
- * SA_SAMPLE_RANDOM The interrupt can be used for entropy
- *
- */
-
-int request_irq(unsigned int irq,
- irqreturn_t (*handler)(int, void *, struct pt_regs *),
- unsigned long irqflags,
- const char * devname,
- void *dev_id)
-{
- int retval;
- struct irqaction * action;
-
-#if 1
- /*
- * Sanity-check: shared interrupts should REALLY pass in
- * a real dev-ID, otherwise we'll have trouble later trying
- * to figure out which interrupt is which (messes up the
- * interrupt freeing logic etc).
- */
- if (irqflags & SA_SHIRQ) {
- if (!dev_id)
- printk("Bad boy: %s (at 0x%x) called us without a dev_id!\n", devname, (&irq)[-1]);
- }
-#endif
-
- if (irq >= NR_IRQS)
- return -EINVAL;
- if (!handler)
- return -EINVAL;
-
- action = (struct irqaction *)
- kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
- if (!action)
- return -ENOMEM;
-
- action->handler = handler;
- action->flags = irqflags;
- cpus_clear(action->mask);
- action->name = devname;
- action->next = NULL;
- action->dev_id = dev_id;
-
- retval = setup_irq(irq, action);
- if (retval)
- kfree(action);
- return retval;
-}
-
-EXPORT_SYMBOL(request_irq);
-
-/**
- * free_irq - free an interrupt
- * @irq: Interrupt line to free
- * @dev_id: Device identity to free
- *
- * Remove an interrupt handler. The handler is removed and if the
- * interrupt line is no longer in use by any driver it is disabled.
- * On a shared IRQ the caller must ensure the interrupt is disabled
- * on the card it drives before calling this function. The function
- * does not return until any executing interrupts for this IRQ
- * have completed.
- *
- * This function must not be called from interrupt context.
- */
-
-void free_irq(unsigned int irq, void *dev_id)
-{
- irq_desc_t *desc;
- struct irqaction **p;
- unsigned long flags;
-
- if (irq >= NR_IRQS)
- return;
-
- desc = irq_desc + irq;
- spin_lock_irqsave(&desc->lock,flags);
- p = &desc->action;
- for (;;) {
- struct irqaction * action = *p;
- if (action) {
- struct irqaction **pp = p;
- p = &action->next;
- if (action->dev_id != dev_id)
- continue;
-
- /* Found it - now remove it from the list of entries */
- *pp = action->next;
- if (!desc->action) {
- desc->status |= IRQ_DISABLED;
- desc->handler->shutdown(irq);
- }
- spin_unlock_irqrestore(&desc->lock,flags);
-
- /* Wait to make sure it's not being used on another CPU */
- synchronize_irq(irq);
- kfree(action);
- return;
- }
- printk("Trying to free free IRQ%d\n",irq);
- spin_unlock_irqrestore(&desc->lock,flags);
- return;
- }
-}
-
-EXPORT_SYMBOL(free_irq);
-
-/*
- * IRQ autodetection code..
- *
- * This depends on the fact that any interrupt that
- * comes in on to an unassigned handler will get stuck
- * with "IRQ_WAITING" cleared and the interrupt
- * disabled.
- */
-
-static DECLARE_MUTEX(probe_sem);
-
-/**
- * probe_irq_on - begin an interrupt autodetect
- *
- * Commence probing for an interrupt. The interrupts are scanned
- * and a mask of potential interrupt lines is returned.
- *
- */
-
-unsigned long probe_irq_on(void)
-{
- unsigned int i;
- irq_desc_t *desc;
- unsigned long val;
- unsigned long delay;
-
- down(&probe_sem);
- /*
- * something may have generated an irq long ago and we want to
- * flush such a longstanding irq before considering it as spurious.
- */
- for (i = NR_IRQS-1; i > 0; i--) {
- desc = irq_desc + i;
-
- spin_lock_irq(&desc->lock);
- if (!irq_desc[i].action)
- irq_desc[i].handler->startup(i);
- spin_unlock_irq(&desc->lock);
- }
-
- /* Wait for longstanding interrupts to trigger. */
- for (delay = jiffies + HZ/50; time_after(delay, jiffies); )
- /* about 20ms delay */ barrier();
-
- /*
- * enable any unassigned irqs
- * (we must startup again here because if a longstanding irq
- * happened in the previous stage, it may have masked itself)
- */
- for (i = NR_IRQS-1; i > 0; i--) {
- desc = irq_desc + i;
-
- spin_lock_irq(&desc->lock);
- if (!desc->action) {
- desc->status |= IRQ_AUTODETECT | IRQ_WAITING;
- if (desc->handler->startup(i))
- desc->status |= IRQ_PENDING;
- }
- spin_unlock_irq(&desc->lock);
- }
-
- /*
- * Wait for spurious interrupts to trigger
- */
- for (delay = jiffies + HZ/10; time_after(delay, jiffies); )
- /* about 100ms delay */ barrier();
-
- /*
- * Now filter out any obviously spurious interrupts
- */
- val = 0;
- for (i = 0; i < NR_IRQS; i++) {
- irq_desc_t *desc = irq_desc + i;
- unsigned int status;
-
- spin_lock_irq(&desc->lock);
- status = desc->status;
-
- if (status & IRQ_AUTODETECT) {
- /* It triggered already - consider it spurious. */
- if (!(status & IRQ_WAITING)) {
- desc->status = status & ~IRQ_AUTODETECT;
- desc->handler->shutdown(i);
- } else
- if (i < 32)
- val |= 1 << i;
- }
- spin_unlock_irq(&desc->lock);
- }
-
- return val;
-}
-
-EXPORT_SYMBOL(probe_irq_on);
-
-/*
- * Return a mask of triggered interrupts (this
- * can handle only legacy ISA interrupts).
- */
-
-/**
- * probe_irq_mask - scan a bitmap of interrupt lines
- * @val: mask of interrupts to consider
- *
- * Scan the ISA bus interrupt lines and return a bitmap of
- * active interrupts. The interrupt probe logic state is then
- * returned to its previous value.
- *
- * Note: we need to scan all the irq's even though we will
- * only return ISA irq numbers - just so that we reset them
- * all to a known state.
- */
-unsigned int probe_irq_mask(unsigned long val)
-{
- int i;
- unsigned int mask;
-
- mask = 0;
- for (i = 0; i < NR_IRQS; i++) {
- irq_desc_t *desc = irq_desc + i;
- unsigned int status;
-
- spin_lock_irq(&desc->lock);
- status = desc->status;
-
- if (status & IRQ_AUTODETECT) {
- if (i < 16 && !(status & IRQ_WAITING))
- mask |= 1 << i;
-
- desc->status = status & ~IRQ_AUTODETECT;
- desc->handler->shutdown(i);
- }
- spin_unlock_irq(&desc->lock);
- }
- up(&probe_sem);
-
- return mask & val;
-}
-
-/*
- * Return the one interrupt that triggered (this can
- * handle any interrupt source).
- */
-
-/**
- * probe_irq_off - end an interrupt autodetect
- * @val: mask of potential interrupts (unused)
- *
- * Scans the unused interrupt lines and returns the line which
- * appears to have triggered the interrupt. If no interrupt was
- * found then zero is returned. If more than one interrupt is
- * found then minus the first candidate is returned to indicate
- * their is doubt.
- *
- * The interrupt probe logic state is returned to its previous
- * value.
- *
- * BUGS: When used in a module (which arguably shouldnt happen)
- * nothing prevents two IRQ probe callers from overlapping. The
- * results of this are non-optimal.
- */
-
-int probe_irq_off(unsigned long val)
-{
- int i, irq_found, nr_irqs;
-
- nr_irqs = 0;
- irq_found = 0;
- for (i = 0; i < NR_IRQS; i++) {
- irq_desc_t *desc = irq_desc + i;
- unsigned int status;
-
- spin_lock_irq(&desc->lock);
- status = desc->status;
-
- if (status & IRQ_AUTODETECT) {
- if (!(status & IRQ_WAITING)) {
- if (!nr_irqs)
- irq_found = i;
- nr_irqs++;
- }
- desc->status = status & ~IRQ_AUTODETECT;
- desc->handler->shutdown(i);
- }
- spin_unlock_irq(&desc->lock);
- }
- up(&probe_sem);
-
- if (nr_irqs > 1)
- irq_found = -irq_found;
- return irq_found;
-}
-
-EXPORT_SYMBOL(probe_irq_off);
-
-/* this was setup_x86_irq but it seems pretty generic */
-int setup_irq(unsigned int irq, struct irqaction * new)
-{
- int shared = 0;
- unsigned long flags;
- struct irqaction *old, **p;
- irq_desc_t *desc = irq_desc + irq;
-
- if (desc->handler == &no_irq_type)
- return -ENOSYS;
- /*
- * Some drivers like serial.c use request_irq() heavily,
- * so we have to be careful not to interfere with a
- * running system.
- */
- if (new->flags & SA_SAMPLE_RANDOM) {
- /*
- * This function might sleep, we want to call it first,
- * outside of the atomic block.
- * Yes, this might clear the entropy pool if the wrong
- * driver is attempted to be loaded, without actually
- * installing a new handler, but is this really a problem,
- * only the sysadmin is able to do this.
- */
- rand_initialize_irq(irq);
- }
-
- /*
- * The following block of code has to be executed atomically
- */
- spin_lock_irqsave(&desc->lock,flags);
- p = &desc->action;
- if ((old = *p) != NULL) {
- /* Can't share interrupts unless both agree to */
- if (!(old->flags & new->flags & SA_SHIRQ)) {
- spin_unlock_irqrestore(&desc->lock,flags);
- return -EBUSY;
- }
-
- /* add new interrupt at end of irq queue */
- do {
- p = &old->next;
- old = *p;
- } while (old);
- shared = 1;
- }
-
- *p = new;
-
- if (!shared) {
- desc->depth = 0;
- desc->status &= ~(IRQ_DISABLED | IRQ_AUTODETECT | IRQ_WAITING | IRQ_INPROGRESS);
- desc->handler->startup(irq);
- }
- spin_unlock_irqrestore(&desc->lock,flags);
-
- register_irq_proc(irq);
- return 0;
-}
-
-static struct proc_dir_entry * root_irq_dir;
-static struct proc_dir_entry * irq_dir [NR_IRQS];
-
-#ifdef CONFIG_SMP
-
-static struct proc_dir_entry *smp_affinity_entry[NR_IRQS];
-
-cpumask_t irq_affinity[NR_IRQS] = { [0 ... NR_IRQS-1] = CPU_MASK_ALL };
-
-static int irq_affinity_read_proc(char *page, char **start, off_t off,
- int count, int *eof, void *data)
-{
- int len = cpumask_scnprintf(page, count, irq_affinity[(long)data]);
- if (count - len < 2)
- return -EINVAL;
- len += sprintf(page + len, "\n");
- return len;
-}
-
-static int irq_affinity_write_proc(struct file *file, const char __user *buffer,
- unsigned long count, void *data)
-{
- int irq = (long)data, full_count = count, err;
- cpumask_t new_value, tmp;
-
- if (!irq_desc[irq].handler->set_affinity)
- return -EIO;
-
- err = cpumask_parse(buffer, count, new_value);
- if (err)
- return err;
-
- /*
- * Do not allow disabling IRQs completely - it's a too easy
- * way to make the system unusable accidentally :-) At least
- * one online CPU still has to be targeted.
- */
- cpus_and(tmp, new_value, cpu_online_map);
- if (cpus_empty(tmp))
- return -EINVAL;
-
- irq_affinity[irq] = new_value;
- irq_desc[irq].handler->set_affinity(irq,
- cpumask_of_cpu(first_cpu(new_value)));
-
- return full_count;
-}
-
-#endif
-#define MAX_NAMELEN 10
-
-static void register_irq_proc (unsigned int irq)
-{
- char name [MAX_NAMELEN];
-
- if (!root_irq_dir || (irq_desc[irq].handler == &no_irq_type) ||
- irq_dir[irq])
- return;
-
- memset(name, 0, MAX_NAMELEN);
- sprintf(name, "%d", irq);
-
- /* create /proc/irq/1234 */
- irq_dir[irq] = proc_mkdir(name, root_irq_dir);
-
-#ifdef CONFIG_SMP
- {
- struct proc_dir_entry *entry;
-
- /* create /proc/irq/1234/smp_affinity */
- entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);
-
- if (entry) {
- entry->nlink = 1;
- entry->data = (void *)(long)irq;
- entry->read_proc = irq_affinity_read_proc;
- entry->write_proc = irq_affinity_write_proc;
- }
-
- smp_affinity_entry[irq] = entry;
- }
-#endif
-}
-
-void init_irq_proc (void)
-{
- int i;
-
- /* create /proc/irq */
- root_irq_dir = proc_mkdir("irq", NULL);
- create_prof_cpu_mask(root_irq_dir);
- /*
- * Create entries for all existing IRQs.
- */
- for (i = 0; i < NR_IRQS; i++)
- register_irq_proc(i);
-}
-
-
#ifdef CONFIG_4KSTACKS
+
/*
* These should really be __section__(".bss.page_aligned") as well, but
* gcc's 3.0 and earlier don't handle that correctly.
*/
-static char softirq_stack[NR_CPUS * THREAD_SIZE] __attribute__((__aligned__(THREAD_SIZE)));
-static char hardirq_stack[NR_CPUS * THREAD_SIZE] __attribute__((__aligned__(THREAD_SIZE)));
+static char softirq_stack[NR_CPUS * THREAD_SIZE]
+ __attribute__((__aligned__(THREAD_SIZE)));
+
+static char hardirq_stack[NR_CPUS * THREAD_SIZE]
+ __attribute__((__aligned__(THREAD_SIZE)));

/*
* allocate per-cpu stacks for hardirq and for softirq processing
@@ -1140,7 +162,6 @@ asmlinkage void do_softirq(void)
/* build the stack frame on the softirq stack */
isp = (u32*) ((char*)irqctx + sizeof(*irqctx));

-
asm volatile(
" xchgl %%ebx,%%esp \n"
" call __do_softirq \n"
@@ -1156,3 +177,74 @@ asmlinkage void do_softirq(void)

EXPORT_SYMBOL(do_softirq);
#endif
+
+/*
+ * Interrupt statistics:
+ */
+
+atomic_t irq_err_count;
+#if defined(CONFIG_X86_IO_APIC) && defined(APIC_MISMATCH_DEBUG)
+atomic_t irq_mis_count;
+#endif
+
+/*
+ * /proc/interrupts printing:
+ */
+
+int show_interrupts(struct seq_file *p, void *v)
+{
+ int i = *(loff_t *) v, j;
+ struct irqaction * action;
+ 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) {
+ spin_lock_irqsave(&irq_desc[i].lock, flags);
+ action = irq_desc[i].action;
+ if (!action)
+ goto skip;
+ seq_printf(p, "%3d: ",i);
+#ifndef CONFIG_SMP
+ seq_printf(p, "%10u ", kstat_irqs(i));
+#else
+ for (j = 0; j < NR_CPUS; j++)
+ if (cpu_online(j))
+ seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
+#endif
+ seq_printf(p, " %14s", irq_desc[i].handler->typename);
+ 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(&irq_desc[i].lock, flags);
+ } else if (i == NR_IRQS) {
+ seq_printf(p, "NMI: ");
+ for (j = 0; j < NR_CPUS; j++)
+ if (cpu_online(j))
+ seq_printf(p, "%10u ", nmi_count(j));
+ seq_putc(p, '\n');
+#ifdef CONFIG_X86_LOCAL_APIC
+ seq_printf(p, "LOC: ");
+ for (j = 0; j < NR_CPUS; j++)
+ if (cpu_online(j))
+ seq_printf(p, "%10u ",
+ irq_stat[j].apic_timer_irqs);
+ seq_putc(p, '\n');
+#endif
+ seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
+#if defined(CONFIG_X86_IO_APIC) && defined(APIC_MISMATCH_DEBUG)
+ seq_printf(p, "MIS: %10u\n", atomic_read(&irq_mis_count));
+#endif
+ }
+ return 0;
+}
--- linux/include/asm-i386/irq.h.orig
+++ linux/include/asm-i386/irq.h
@@ -21,38 +21,17 @@ static __inline__ int irq_canonicalize(i
return ((irq == 2) ? 9 : irq);
}

-extern void disable_irq(unsigned int);
-extern void disable_irq_nosync(unsigned int);
-extern void enable_irq(unsigned int);
-extern void release_x86_irqs(struct task_struct *);
-extern int can_request_irq(unsigned int, unsigned long flags);
+extern void release_vm86_irqs(struct task_struct *);

#ifdef CONFIG_X86_LOCAL_APIC
-#define ARCH_HAS_NMI_WATCHDOG /* See include/linux/nmi.h */
+# define ARCH_HAS_NMI_WATCHDOG /* See include/linux/nmi.h */
#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)];
-};
-
-extern union irq_ctx *hardirq_ctx[NR_CPUS];
-extern union irq_ctx *softirq_ctx[NR_CPUS];
-
-extern void irq_ctx_init(int cpu);
-
-#define __ARCH_HAS_DO_SOFTIRQ
+ extern void irq_ctx_init(int cpu);
+# define __ARCH_HAS_DO_SOFTIRQ
#else
-#define irq_ctx_init(cpu) do { ; } while (0)
+# define irq_ctx_init(cpu) do { } while (0)
#endif

-struct irqaction;
-struct pt_regs;
-asmlinkage int handle_IRQ_event(unsigned int, struct pt_regs *,
- struct irqaction *);
-
#endif /* _ASM_IRQ_H */
--- linux/include/asm-i386/hardirq.h.orig
+++ linux/include/asm-i386/hardirq.h
@@ -15,47 +15,25 @@ typedef struct {
#include <linux/irq_cpustat.h> /* Standard mappings for irq_cpustat_t above */

/*
- * We put the hardirq and softirq counter into the preemption
- * counter. The bitmask has the following meaning:
- *
- * - bits 0-7 are the preemption count (max preemption depth: 256)
- * - bits 8-15 are the softirq count (max # of softirqs: 256)
- * - bits 16-23 are the hardirq count (max # of hardirqs: 256)
- *
- * - ( bit 26 is the PREEMPT_ACTIVE flag. )
- *
- * PREEMPT_MASK: 0x000000ff
- * SOFTIRQ_MASK: 0x0000ff00
- * HARDIRQ_MASK: 0x00ff0000
+ * 'what should we do if we get a hw irq event on an illegal vector'.
+ * each architecture has to answer this themselves.
*/
-
-#define PREEMPT_BITS 8
-#define SOFTIRQ_BITS 8
-#define HARDIRQ_BITS 8
-
-#define PREEMPT_SHIFT 0
-#define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS)
-#define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS)
-
-/*
- * The hardirq mask has to be large enough to have
- * space for potentially all IRQ sources in the system
- * nesting on a single CPU:
- */
-#if (1 << HARDIRQ_BITS) < NR_IRQS
-# error HARDIRQ_BITS is too low!
+static inline void ack_bad_irq(unsigned int irq)
+{
+#ifdef CONFIG_X86
+ printk("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.
+ */
+ ack_APIC_irq();
#endif
-
-#define nmi_enter() (irq_enter())
-#define nmi_exit() (preempt_count() -= HARDIRQ_OFFSET)
-
-#define irq_enter() (preempt_count() += HARDIRQ_OFFSET)
-#define irq_exit() \
-do { \
- preempt_count() -= IRQ_EXIT_OFFSET; \
- if (!in_interrupt() && softirq_pending(smp_processor_id())) \
- do_softirq(); \
- preempt_enable_no_resched(); \
-} while (0)
+#endif
+}

#endif /* __ASM_HARDIRQ_H */
--- linux/include/asm-i386/hw_irq.h.orig
+++ linux/include/asm-i386/hw_irq.h
@@ -45,8 +45,6 @@ asmlinkage void thermal_interrupt(struct
#define platform_legacy_irq(irq) ((irq) < 16)
#endif

-void mask_irq(unsigned int irq);
-void unmask_irq(unsigned int irq);
void disable_8259A_irq(unsigned int irq);
void enable_8259A_irq(unsigned int irq);
int i8259A_irq_pending(unsigned int irq);
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/