[PATCH][RFC] irq handling code consolidation (common part)

[PATCH][RFC] irq handling code consolidation (common part)

[Andrey Panin]

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Hi all,

the irq handling consolidation patch returns from the dead !
Now with runaway irq detection code included !

This patch (against 2.5.73) contains common part of it.

Please take a look.

Best regards.

-- 
Andrey Panin		| Linux and UNIX system administrator
pazke@donpac.ru		| PGP key: wwwkeys.pgp.net

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diff --minimal -urN -X /usr/share/dontdiff linux-2.5.72.vanilla/kernel/irq.c linux-2.5.72/kernel/irq.c
--- linux-2.5.72.vanilla/kernel/irq.c	1970-01-01 03:00:00.000000000 +0300
+++ linux-2.5.72/kernel/irq.c	2003-06-17 23:01:44.000000000 +0400
@@ -0,0 +1,904 @@
+/*
+ *  linux/kernel/irq.c
+ *
+ *  Architecture independent parts of IRQ handling.
+ *
+ *  Copyright (C) 1992-2002 Linus Torvalds.
+ *
+ *  Modified from the alpha version by Andrey Panin.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
+ */
+
+/*
+ * 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.
+ *
+ * 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.
+ *
+ * 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.
+ *
+ * The code is designed to be easily extended with new/different
+ * interrupt controllers, without having to do assembly magic.
+ */
+
+#include <linux/config.h>
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include <linux/signal.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/random.h>
+#include <linux/jiffies.h>
+#include <linux/proc_fs.h>
+#include <linux/stringify.h>
+#include <linux/kallsyms.h>
+
+#include <asm/param.h>
+#include <asm/semaphore.h>
+#include <asm/hw_irq.h>
+#include <asm/uaccess.h>
+
+#ifndef HAVE_ARCH_IRQ_DESC
+
+/*
+ * 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,
+	}
+};
+
+#endif
+
+/*
+ * Special irq handlers.
+ */
+
+irqreturn_t no_action(int cpl, void *dev_id, struct pt_regs *regs)
+{
+	return IRQ_NONE;
+}
+
+/*
+ * Generic no controller code
+ */
+atomic_t irq_err_count;
+
+static void no_irq_enable_disable(unsigned int irq) { }
+static unsigned int no_irq_startup(unsigned int irq) { return 0; }
+
+static void no_irq_ack(unsigned int irq)
+{
+	atomic_inc(&irq_err_count);
+	printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq);
+	arch_ack_bad_irq(irq);
+}
+
+struct hw_interrupt_type no_irq_type = {
+	.typename	= "none",
+	.startup	= no_irq_startup,
+	.shutdown	= no_irq_enable_disable,
+	.enable		= no_irq_enable_disable,
+	.disable	= no_irq_enable_disable,
+	.ack		= no_irq_ack,
+	.end		= no_irq_enable_disable,
+};
+
+/*
+ * 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.
+ */
+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);
+	}
+}
+
+int noirqdebug;
+
+static int __init noirqdebug_setup(char *str)
+{
+	noirqdebug = 1;
+	printk(KERN_INFO "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
+ */
+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;
+}
+
+#if defined(CONFIG_SMP) && !defined(HAVE_ARCH_SYNCRONIZE_IRQ)
+
+inline void synchronize_irq(unsigned int irq)
+{
+	irq_desc_t *desc = irq_desc(irq);
+
+        /* is there anything to synchronize with? */
+	if (!desc->action)
+		return;
+
+	while (desc->status & IRQ_INPROGRESS)
+		cpu_relax();
+}
+
+#endif
+
+/*
+ * Workarounds for interrupt types without startup()/shutdown() (ppc, ppc64).
+ * Will be removed some day.
+ */
+
+static int startup_irq(unsigned int irq)
+{
+	irq_desc_t *desc = irq_desc(irq);
+
+	if (desc->handler->startup)
+		return desc->handler->startup(irq);
+	else if (desc->handler->enable)
+		desc->handler->enable(irq);
+	else 
+		BUG();
+	return 0;
+}
+
+static void shutdown_irq(unsigned int irq)
+{
+	irq_desc_t *desc = irq_desc(irq);
+
+	if (desc->handler->shutdown)
+		desc->handler->shutdown(irq);
+	else if (desc->handler->disable)
+		desc->handler->disable(irq);
+	else 
+		BUG();
+}
+
+/*
+ * 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++) {
+		/* Needed for ppc & ppc64, doesn't harm others (really ?) */
+		if (!(desc->status & IRQ_PER_CPU))
+			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. That is for two disables you need two enables.
+ *	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)
+{
+	disable_irq_nosync(irq);
+	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(KERN_ERR "enable_irq(%u) unbalanced from %p\n",
+		       irq, __builtin_return_address(0));
+	}
+	spin_unlock_irqrestore(&desc->lock, flags);
+}
+
+/**
+ *	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;
+
+	/*
+	 * 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(KERN_ERR "Bad boy: %s (at %p) called us " \
+				"without a dev_id!\n", devname,
+				__builtin_return_address(0));
+	}
+
+	if (!irq_valid(irq) || !handler)
+		return -EINVAL;
+
+	action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
+	if (!action)
+		return -ENOMEM;
+
+	action->handler = handler;
+	action->flags = irqflags;
+	action->mask = 0;
+	action->name = devname;
+	action->next = NULL;
+	action->dev_id = dev_id;
+
+	retval = setup_irq(irq, action);
+	if (retval)
+		kfree(action);
+	return retval;
+}
+
+#ifndef HAVE_ARCH_IRQ_PROC
+void register_irq_proc(unsigned int irq);
+#endif
+
+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);
+	}
+
+	arch_setup_irq(irq, desc, new);
+
+	/*
+	 * 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 &= ARCH_NONSHARED_IRQ_MASK;
+		startup_irq(irq);
+	}
+	spin_unlock_irqrestore(&desc->lock, flags);
+
+	register_irq_proc(irq);
+
+	return 0;
+}
+
+/**
+ *	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_valid(irq)) {
+		printk(KERN_CRIT "Trying to free IRQ%d\n", irq);
+		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;
+				shutdown_irq(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(KERN_CRIT "Trying to free free IRQ%d\n", irq);
+		spin_unlock_irqrestore(&desc->lock, flags);
+		return;
+	}
+}
+
+#ifndef HAVE_ARCH_IRQ_PROBE
+
+/*
+ * 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 (!desc->action) 
+			startup_irq(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 (startup_irq(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;
+				shutdown_irq(i);
+			} else
+				if (i < 32)
+					val |= 1 << i;
+		}
+		spin_unlock_irq(&desc->lock);
+	}
+
+	return val;
+}
+
+/**
+ *	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. This function can handle only 
+ *	legacy ISA interrupts
+ *
+ *	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;
+			shutdown_irq(i);
+		}
+		spin_unlock_irq(&desc->lock);
+	}
+	up(&probe_sem);
+
+	return mask & val;
+}
+
+/**
+ *	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. This function can handle any interrupt source.
+ *
+ *	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;
+			shutdown_irq(i);
+		}
+		spin_unlock_irq(&desc->lock);
+	}
+	up(&probe_sem);
+
+	if (nr_irqs > 1)
+		irq_found = -irq_found;
+	return irq_found;
+}
+
+#endif	/* HAVE_ARCH_IRQ_PROBE */
+
+#ifndef HAVE_ARCH_IRQ_PROC
+
+unsigned int parse_hex_value(const char __user *buffer, unsigned long count, 
+			     unsigned long *ret)
+{
+	unsigned char hexnum[ARCH_AFFINITY_WIDTH];
+	unsigned long value, i;
+
+	if (!count)
+		return -EINVAL;
+	if (count > ARCH_AFFINITY_WIDTH)
+		count = ARCH_AFFINITY_WIDTH;
+	if (copy_from_user(hexnum, buffer, count))
+		return -EFAULT;
+
+	/*
+	 * Parse the first ARCH_AFFINITY_WIDTH characters as a hex
+	 * string, any non-hex char is end-of-string. '00e1', 'e1', '00E1',
+	 * 'E1' are all the same.
+	 */
+	value = 0;
+
+	for (i = 0; i < count; i++) {
+		unsigned int c = hexnum[i];
+
+		switch (c) {
+			case '0' ... '9': c -= '0'; break;
+			case 'a' ... 'f': c -= 'a' - 10; break;
+			case 'A' ... 'F': c -= 'A' - 10; break;
+		default:
+			goto out;
+		}
+		value = (value << 4) | c;
+	}
+out:
+	*ret = value;
+	return 0;
+}
+
+#define MAX_NAMELEN 10
+
+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];
+
+unsigned long irq_affinity[NR_IRQS] = { 
+	[0 ... NR_IRQS - 1] = ARCH_DEFAULT_IRQ_AFFINITY
+};
+
+static int irq_affinity_read_proc(char *page, char **start, off_t off,
+				  int count, int *eof, void *data)
+{
+	if (count < ARCH_AFFINITY_WIDTH + 1)
+		return -EINVAL;
+	return sprintf (page, "%0" __stringify(ARCH_AFFINITY_WIDTH) "lx\n",
+			irq_affinity[(long)data]);
+}
+
+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;
+	unsigned long new_value;
+
+	if (!irq_desc(irq)->handler->set_affinity)
+		return -EIO;
+
+	err = parse_hex_value(buffer, count, &new_value);
+
+	/*
+	 * 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.
+	 */
+	if (!(new_value & cpu_online_map))
+		return -EINVAL;
+
+	irq_affinity[irq] = new_value;
+	irq_desc(irq)->handler->set_affinity(irq, new_value);
+
+	return full_count;
+}
+#endif
+
+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
+	if (irq_desc(irq)->handler->set_affinity) {
+		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
+}
+
+#ifdef CONFIG_SMP
+
+unsigned long prof_cpu_mask = ~0UL;
+
+static int prof_cpu_mask_read_proc(char *page, char **start, off_t off,
+				   int count, int *eof, void *data)
+{
+	unsigned long *mask = (unsigned long *) data;
+	if (count < ARCH_AFFINITY_WIDTH + 1)
+		return -EINVAL;
+	return sprintf (page, "%0" __stringify(ARCH_AFFINITY_WIDTH) "lx\n", 
+			*mask);
+}
+
+static int prof_cpu_mask_write_proc(struct file *file, const char __user *buffer,
+				    unsigned long count, void *data)
+{
+	unsigned long *mask = (unsigned long *) data, full_count = count, err;
+	unsigned long new_value;
+
+	err = parse_hex_value(buffer, count, &new_value);
+	if (err)
+		return err;
+
+	*mask = new_value;
+	return full_count;
+}
+#endif
+
+void init_irq_proc(void)
+{
+	int i;
+
+	/* create /proc/irq */
+	root_irq_dir = proc_mkdir("irq", 0);
+
+#ifdef CONFIG_SMP
+	{
+		struct proc_dir_entry *entry;
+
+		/* 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;
+	}
+#endif
+
+	/*
+	 * Create entries for all existing IRQs.
+	 */
+	if (arch_can_create_irq_proc())
+		for (i = 0; irq_valid(i); i++)
+			if (irq_desc(i)->handler != &no_irq_type)
+				register_irq_proc(i);
+}
+
+#endif	/* HAVE_ARCH_IRQ_PROC */
diff --minimal -urN -X /usr/share/dontdiff linux-2.5.72.vanilla/kernel/Makefile linux-2.5.72/kernel/Makefile
--- linux-2.5.72.vanilla/kernel/Makefile	2003-06-17 20:00:48.000000000 +0400
+++ linux-2.5.72/kernel/Makefile	2003-06-17 22:26:07.000000000 +0400
@@ -19,6 +19,7 @@
 obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
 obj-$(CONFIG_SOFTWARE_SUSPEND) += suspend.o
 obj-$(CONFIG_COMPAT) += compat.o
+obj-$(CONFIG_GENERIC_IRQ) += irq.o
 
 ifneq ($(CONFIG_IA64),y)
 # According to Alan Modra <alan@linuxcare.com.au>, the -fno-omit-frame-pointer is

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Re: [PATCH][RFC] irq handling code consolidation (common part)

[Christoph Hellwig]

> +#ifndef HAVE_ARCH_IRQ_DESC
> +
> +/*
> + * 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,
> +	}
> +};
> +
> +#endif

What about getting rid of that ifdef and having irq_desc always
in arch code?  Seems a lot cleaner to me.

> +#if defined(CONFIG_SMP) && !defined(HAVE_ARCH_SYNCRONIZE_IRQ)
> +
> +inline void synchronize_irq(unsigned int irq)
> +{
> +	irq_desc_t *desc = irq_desc(irq);
> +
> +        /* is there anything to synchronize with? */
> +	if (!desc->action)
> +		return;
> +
> +	while (desc->status & IRQ_INPROGRESS)
> +		cpu_relax();
> +}
> +
> +#endif

Hmm, what arch can't use the generic version and why?  I really
don't like the HAVE_ARCH_ macros if there's a way around it.

> +#ifndef HAVE_ARCH_IRQ_PROC
> +void register_irq_proc(unsigned int irq);
> +#endif

Again, what arch can't use the generic code?

> +#ifndef HAVE_ARCH_IRQ_PROBE
> +
> +/*
> + * 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.
> + */

Which architecture uses it's own version here?  Also we might
move this to a separate file as it doesn't make a lot of sense
without CONFIG_ISA

Otherwise it looks fine (of course)!  Let's hope we'll get some variant
of it in before 2.6.

Re: [PATCH][RFC] irq handling code consolidation (common part)

[Anton Blanchard]

> the irq handling consolidation patch returns from the dead !
> Now with runaway irq detection code included !
> 
> This patch (against 2.5.73) contains common part of it.

Great! Well it wasnt dead, I was also keeping it up to date and sending
it on to akpm :)

I have two suggestions that will help in my crusade to kill NR_IRQS.

1. define irq_desc, irq_valid, for_each_irq in include/linux/irq.h if
HAVE_ARCH_IRQ_DESC isnt defined (instead of in each architecture).
Basically I want to start using these macros in a few places and dont
want to break every architecture that hasnt converted to the new scheme.

On the other hand if we decide to move the irq descriptor definition
into each arch as hch suggested, this wont be necessary as all archs
will break anyway :)

2. define irq_atoi that converts an irq into a printable string. We have
a bunch of #ifdef CONFIG_SPARC stuff we can then get rid of, and other
archs can start using it if wanted (eg on ppc64 I can subtract our
software offset so the irqs printed match the hardware)

Anton

Re: [PATCH][RFC] irq handling code consolidation (common part)

[Andrey Panin]

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On 177, 06 26, 2003 at 12:13:18PM +0100, Christoph Hellwig wrote:
> > +#ifndef HAVE_ARCH_IRQ_DESC
> > +
> > +/*
> > + * 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,
> > +	}
> > +};
> > +
> > +#endif
> 
> What about getting rid of that ifdef and having irq_desc always
> in arch code?  Seems a lot cleaner to me.

So it will be duplicated in allmost every architecture ?

> > +#if defined(CONFIG_SMP) && !defined(HAVE_ARCH_SYNCRONIZE_IRQ)
> > +
> > +inline void synchronize_irq(unsigned int irq)
> > +{
> > +	irq_desc_t *desc = irq_desc(irq);
> > +
> > +        /* is there anything to synchronize with? */
> > +	if (!desc->action)
> > +		return;
> > +
> > +	while (desc->status & IRQ_INPROGRESS)
> > +		cpu_relax();
> > +}
> > +
> > +#endif
> 
> Hmm, what arch can't use the generic version and why?  I really
> don't like the HAVE_ARCH_ macros if there's a way around it.

This function implemented differently in allmost every architecture.
I beleive that most of them can use generic version, but I'm still not sure.
v850 and mips define synchronize_irq() as barrier() for example.
 
> > +#ifndef HAVE_ARCH_IRQ_PROC
> > +void register_irq_proc(unsigned int irq);
> > +#endif
> 
> Again, what arch can't use the generic code?

IIRC v850 architecture doesn't need it at all.
 
> > +#ifndef HAVE_ARCH_IRQ_PROBE
> > +
> > +/*
> > + * 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.
> > + */
> 
> Which architecture uses it's own version here?  Also we might
> move this to a separate file as it doesn't make a lot of sense
> without CONFIG_ISA

Some architectures provide empty stubs for these functions.
I'm not sure about CONFIG_ISA, IMHO any legacy device driver
can use irq autoprobing.

> Otherwise it looks fine (of course)!  Let's hope we'll get some variant
> of it in before 2.6.

-- 
Andrey Panin		| Linux and UNIX system administrator
pazke@donpac.ru		| PGP key: wwwkeys.pgp.net

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Re: [PATCH][RFC] irq handling code consolidation (common part)

[Andrey Panin]

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On 178, 06 27, 2003 at 03:55:54AM +1000, Anton Blanchard wrote:
> 
> > the irq handling consolidation patch returns from the dead !
> > Now with runaway irq detection code included !
> > 
> > This patch (against 2.5.73) contains common part of it.
> 
> Great! Well it wasnt dead, I was also keeping it up to date and sending
> it on to akpm :)
>
> I have two suggestions that will help in my crusade to kill NR_IRQS.
> 
> 1. define irq_desc, irq_valid, for_each_irq in include/linux/irq.h if
> HAVE_ARCH_IRQ_DESC isnt defined (instead of in each architecture).
> Basically I want to start using these macros in a few places and dont
> want to break every architecture that hasnt converted to the new scheme.

Why in include/linux/irq.h ? These macros are definetely arch specific.
Do you talk about generic array based implementation wrapped in 
#ifdef ARCH_HAVE_FOO ?
 
> On the other hand if we decide to move the irq descriptor definition
> into each arch as hch suggested, this wont be necessary as all archs
> will break anyway :)

Why it will break ? Every arch defines irq descriptors itself now.
May be I'm missing some point here ?

> 2. define irq_atoi that converts an irq into a printable string. We have
> a bunch of #ifdef CONFIG_SPARC stuff we can then get rid of, and other
> archs can start using it if wanted (eg on ppc64 I can subtract our
> software offset so the irqs printed match the hardware)

I thinked about this already, but i wanted to finish cleanup work first.

BTW sparc implementation of irq_itoa() uses static buffer for the formatted 
string, is it really irq/preempt safe ?

-- 
Andrey Panin		| Linux and UNIX system administrator
pazke@donpac.ru		| PGP key: wwwkeys.pgp.net

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Re: [PATCH][RFC] irq handling code consolidation (common part)

[Miles Bader]

Andrey Panin <pazke@donpac.ru> writes:
> BTW sparc implementation of irq_itoa() uses static buffer for the formatted 
> string, is it really irq/preempt safe ?

Passinf in a result buffer seems simplest (maybe have the arch define a
macro for the max-length).

[btw the name `irq_itoa' seems a bit odd; how about `irq_name' (or
`irq_rep' for clu-lovers)?]

-miLes
-- 
Somebody has to do something, and it's just incredibly pathetic that it
has to be us.  -- Jerry Garcia