generic hardirq handling for uml

From: Martin Waitz
Date: Tue Oct 19 2004 - 21:16:34 EST


hoi :)

I just ported arch/um to generic hardirq handling.
It works for me on a 2.6.9-rc4-mm1 kernel.

Without this patch, ARCH=um does not build as it tries
to use arch/hardirq.h which is already ported to generic
hardirq on i386.

Signed-off-by: Martin Waitz <tali@xxxxxxxxxxxxxx>

Index: linux-2.6/arch/um/Kconfig
===================================================================
--- linux-2.6.orig/arch/um/Kconfig 2004-10-17 18:36:05.000000000 +0200
+++ linux-2.6/arch/um/Kconfig 2004-10-17 18:36:19.000000000 +0200
@@ -7,6 +7,13 @@
bool
default y

+#
+# Use the generic interrupt handling code in kernel/irq/:
+#
+config GENERIC_HARDIRQS
+ bool
+ default y
+
mainmenu "Linux/Usermode Kernel Configuration"

config ISA
Index: linux-2.6/arch/um/kernel/irq.c
===================================================================
--- linux-2.6.orig/arch/um/kernel/irq.c 2004-10-17 18:35:12.000000000 +0200
+++ linux-2.6/arch/um/kernel/irq.c 2004-10-20 00:36:08.000000000 +0200
@@ -5,89 +5,64 @@
* Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
*/

-#include "linux/config.h"
#include "linux/kernel.h"
#include "linux/module.h"
#include "linux/smp.h"
#include "linux/irq.h"
#include "linux/kernel_stat.h"
#include "linux/interrupt.h"
-#include "linux/random.h"
-#include "linux/slab.h"
#include "linux/file.h"
-#include "linux/proc_fs.h"
#include "linux/init.h"
#include "linux/seq_file.h"
#include "linux/profile.h"
#include "linux/hardirq.h"
-#include "asm/irq.h"
-#include "asm/hw_irq.h"
-#include "asm/atomic.h"
-#include "asm/signal.h"
-#include "asm/system.h"
-#include "asm/errno.h"
-#include "asm/uaccess.h"
#include "user_util.h"
#include "kern_util.h"
#include "irq_user.h"
#include "irq_kern.h"

-static void register_irq_proc (unsigned int irq);

-irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned = {
- [0 ... NR_IRQS-1] = {
- .handler = &no_irq_type,
- .lock = SPIN_LOCK_UNLOCKED
- }
-};
+void ack_bad_irq(unsigned int irq)
+{
+ printk("unexpected IQ trap at vector %02x\n", irq);
+}

/*
- * Generic no controller code
+ * do_IRQ handles all normal device IRQ's (the special
+ * SMP cross-CPU interrupts have their own specific
+ * handlers).
*/
+unsigned int do_IRQ(int irq, union uml_pt_regs *regs)
+{
+ irq_enter();
+
+ __do_IRQ(irq, (struct pt_regs *) regs);
+
+ irq_exit();
+
+ return 1;
+}
+

-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)
+int um_request_irq(unsigned int irq, int fd, int type,
+ irqreturn_t (*handler)(int, void *, struct pt_regs *),
+ unsigned long irqflags, const char * devname,
+ void *dev_id)
{
-/*
- * '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(KERN_ERR "unexpected IRQ trap at vector %02x\n", irq);
-#ifdef CONFIG_X86_LOCAL_APIC
- /*
- * Currently unexpected vectors happen only on SMP and APIC.
- * We _must_ ack these because every local APIC has only N
- * irq slots per priority level, and a 'hanging, unacked' IRQ
- * holds up an irq slot - in excessive cases (when multiple
- * unexpected vectors occur) that might lock up the APIC
- * completely.
- */
- ack_APIC_irq();
-#endif
-#endif
+ int err;
+
+ err = request_irq(irq, handler, irqflags, devname, dev_id);
+ if(err)
+ return(err);
+
+ if(fd != -1)
+ err = activate_fd(irq, fd, type, dev_id);
+ return(err);
}
+EXPORT_SYMBOL(um_request_irq);
+EXPORT_SYMBOL(reactivate_fd);

-/* 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
-};

-/*
- * Generic, controller-independent functions:
- */

int show_interrupts(struct seq_file *p, void *v)
{
@@ -136,530 +111,6 @@
return 0;
}

-/*
- * 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 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;
-}
-
-/*
- * 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 of an interrupt
- * stack. 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);
-}
-
-#ifdef CONFIG_SMP
-inline void synchronize_irq(unsigned int irq)
-{
- /* is there anything to synchronize with? */
- if (!irq_desc[irq].action)
- return;
-
- while (irq_desc[irq].status & IRQ_INPROGRESS)
- cpu_relax();
-}
-#endif
-
-/**
- * disable_irq - disable an irq and wait for completion
- * @irq: Interrupt to disable
- *
- * Disable the selected interrupt line. Disables of an interrupt
- * stack. 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 interrupt handling on an irq
- * @irq: Interrupt to enable
- *
- * Re-enables the processing of interrupts on this IRQ line
- * providing no disable_irq calls are now in effect.
- *
- * 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() unbalanced from %p\n",
- __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).
- */
-unsigned int do_IRQ(int irq, union uml_pt_regs *regs)
-{
- /*
- * 0 return value means that this irq is already being
- * handled by some other CPU. (or is disabled)
- */
- irq_desc_t *desc = irq_desc + irq;
- struct irqaction * action;
- unsigned int status;
-
- irq_enter();
- 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 (!(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 (!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.
- */
- for (;;) {
- spin_unlock(&desc->lock);
- handle_IRQ_event(irq, (struct pt_regs *) regs, action);
- spin_lock(&desc->lock);
-
- if (!(desc->status & IRQ_PENDING))
- break;
- desc->status &= ~IRQ_PENDING;
- }
- 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;
-}
-
-/**
- * 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(KERN_ERR "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_KERNEL);
- 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);
-
-int um_request_irq(unsigned int irq, int fd, int type,
- irqreturn_t (*handler)(int, void *, struct pt_regs *),
- unsigned long irqflags, const char * devname,
- void *dev_id)
-{
- int err;
-
- err = request_irq(irq, handler, irqflags, devname, dev_id);
- if(err)
- return(err);
-
- if(fd != -1)
- err = activate_fd(irq, fd, type, dev_id);
- return(err);
-}
-EXPORT_SYMBOL(um_request_irq);
-EXPORT_SYMBOL(reactivate_fd);
-
-/* 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;
-
- /*
- * 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;
- old = *p;
- if (old != 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;
- desc->handler->startup(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 may be called from interrupt context.
- *
- * Bugs: Attempting to free an irq in a handler for the same irq hangs
- * the machine.
- */
-
-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);
- }
- free_irq_by_irq_and_dev(irq, dev_id);
- 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_ERR "Trying to free free IRQ%d\n",irq);
- spin_unlock_irqrestore(&desc->lock,flags);
- return;
- }
-}
-
-EXPORT_SYMBOL(free_irq);
-
-/* These are initialized by sysctl_init, which is called from init/main.c */
-static struct proc_dir_entry * root_irq_dir;
-static struct proc_dir_entry * irq_dir [NR_IRQS];
-static struct proc_dir_entry * smp_affinity_entry [NR_IRQS];
-
-/* These are read and written as longs, so a read won't see a partial write
- * even during a race.
- */
-static 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 *buffer,
- unsigned long count, void *data)
-{
- int irq = (long) data, full_count = count, err;
- cpumask_t new_value;
-
- if (!irq_desc[irq].handler->set_affinity)
- return -EIO;
-
- err = cpumask_parse(buffer, count, new_value);
- if(err)
- return(err);
-
-#ifdef CONFIG_SMP
- /*
- * 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.
- */
- { cpumask_t tmp;
- cpus_and(tmp, new_value, cpu_online_map);
- if (cpus_empty(tmp))
- return -EINVAL;
- }
-#endif
-
- irq_affinity[irq] = new_value;
- irq_desc[irq].handler->set_affinity(irq, new_value);
-
- return full_count;
-}
-
-#define MAX_NAMELEN 10
-
-static void register_irq_proc (unsigned int irq)
-{
- struct proc_dir_entry *entry;
- 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);
-
- /* create /proc/irq/1234/smp_affinity */
- entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);
-
- 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;
-}
-
-void __init init_irq_proc (void)
-{
- int i;
-
- /* create /proc/irq */
- root_irq_dir = proc_mkdir("irq", 0);
-
- /* create /proc/irq/prof_cpu_mask */
- create_prof_cpu_mask(root_irq_dir);
-
- /*
- * Create entries for all existing IRQs.
- */
- for (i = 0; i < NR_IRQS; i++)
- register_irq_proc(i);
-}
-
static spinlock_t irq_spinlock = SPIN_LOCK_UNLOCKED;

unsigned long irq_lock(void)
@@ -675,20 +126,6 @@
spin_unlock_irqrestore(&irq_spinlock, flags);
}

-unsigned long probe_irq_on(void)
-{
- return(0);
-}
-
-EXPORT_SYMBOL(probe_irq_on);
-
-int probe_irq_off(unsigned long val)
-{
- return(0);
-}
-
-EXPORT_SYMBOL(probe_irq_off);
-
static unsigned int startup_SIGIO_irq(unsigned int irq)
{
return(0);

--
Martin Waitz

Attachment: signature.asc
Description: Digital signature