/*
* linux/arch/i386/kernel/irq.c
*
* 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.
*/
/*
* (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 <linux/module.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/ioport.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
*/
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
};
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();
}
#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 retval = 0;
if (!(action->flags & SA_INTERRUPT))
local_irq_enable();
do {
status |= action->flags;
retval |= action->handler(irq, action->dev_id, regs);
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;
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
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;
/*
* 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;
/*
* 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.
*/
#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, ®s, 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) ®s;
*--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);
action_ret = handle_IRQ_event(irq, ®s, action);
spin_lock(&desc->lock);
if (!noirqdebug)
note_interrupt(irq, desc, action_ret);
if (likely(!(desc->status & IRQ_PENDING)))
break;
desc->status &= ~IRQ_PENDING;
}
#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);
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
static int prof_cpu_mask_read_proc (char *page, char **start, off_t off,
int count, int *eof, void *data)
{
int len = cpumask_scnprintf(page, count, *(cpumask_t *)data);
if (count - len < 2)
return -EINVAL;
len += sprintf(page + len, "\n");
return len;
}
static int prof_cpu_mask_write_proc (struct file *file, const char __user *buffer,
unsigned long count, void *data)
{
cpumask_t *mask = (cpumask_t *)data;
unsigned long full_count = count, err;
cpumask_t new_value;
err = cpumask_parse(buffer, count, new_value);
if (err)
return err;
*mask = new_value;
return full_count;
}
#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
}
unsigned long prof_cpu_mask = -1;
void init_irq_proc (void)
{
struct proc_dir_entry *entry;
int i;
/* create /proc/irq */
root_irq_dir = proc_mkdir("irq", NULL);
/* create /proc/irq/prof_cpu_mask */
entry = create_proc_entry("prof_cpu_mask", 0600, root_irq_dir);
if (!entry)
return;
entry->nlink = 1;
entry->data = (void *)&prof_cpu_mask;
entry->read_proc = prof_cpu_mask_read_proc;
entry->write_proc = prof_cpu_mask_write_proc;
/*
* 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)));
/*
* allocate per-cpu stacks for hardirq and for softirq processing
*/
void irq_ctx_init(int cpu)
{
union irq_ctx *irqctx;
if (hardirq_ctx[cpu])
return;
irqctx = (union irq_ctx*) &hardirq_stack[cpu*THREAD_SIZE];
irqctx->tinfo.task = NULL;
irqctx->tinfo.exec_domain = NULL;
irqctx->tinfo.cpu = cpu;
irqctx->tinfo.preempt_count = HARDIRQ_OFFSET;
irqctx->tinfo.addr_limit = MAKE_MM_SEG(0);
hardirq_ctx[cpu] = irqctx;
irqctx = (union irq_ctx*) &softirq_stack[cpu*THREAD_SIZE];
irqctx->tinfo.task = NULL;
irqctx->tinfo.exec_domain = NULL;
irqctx->tinfo.cpu = cpu;
irqctx->tinfo.preempt_count = SOFTIRQ_OFFSET;
irqctx->tinfo.addr_limit = MAKE_MM_SEG(0);
softirq_ctx[cpu] = irqctx;
printk("CPU %u irqstacks, hard=%p soft=%p\n",
cpu,hardirq_ctx[cpu],softirq_ctx[cpu]);
}
extern asmlinkage void __do_softirq(void);
asmlinkage void do_softirq(void)
{
unsigned long flags;
struct thread_info *curctx;
union irq_ctx *irqctx;
u32 *isp;
if (in_interrupt())
return;
local_irq_save(flags);
if (local_softirq_pending()) {
curctx = current_thread_info();
irqctx = softirq_ctx[smp_processor_id()];
irqctx->tinfo.task = curctx->task;
irqctx->tinfo.previous_esp = current_stack_pointer();
/* build the stack frame on the softirq stack */
isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
asm volatile(
" xchgl %%ebx,%%esp \n"
" call __do_softirq \n"
" movl %%ebx,%%esp \n"
: "=b"(isp)
: "0"(isp)
: "memory", "cc", "edx", "ecx", "eax"
);
}
local_irq_restore(flags);
}
EXPORT_SYMBOL(do_softirq);
#endif
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