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Subject[RFC] irq handling code consolidation (x86_64)

x86_64 specific patch attached. Not tested, not compiled.

--
Andrey Panin | Embedded systems software developer
pazke@orbita1.ru | PGP key: wwwkeys.pgp.netdiff --minimal -urN -X /usr/share/dontdiff linux-2.5.52.vanilla/arch/x86_64/Kconfig linux-2.5.52/arch/x86_64/Kconfig
--- linux-2.5.52.vanilla/arch/x86_64/Kconfig Thu Dec 19 20:02:33 2002
+++ linux-2.5.52/arch/x86_64/Kconfig Tue Dec 24 20:40:18 2002
@@ -25,6 +25,10 @@
486, 586, Pentiums, and various instruction-set-compatible chips by
AMD, Cyrix, and others.

+config GENERIC_IRQ
+ bool
+ default y
+
config MMU
bool
default y
diff --minimal -urN -X /usr/share/dontdiff linux-2.5.52.vanilla/arch/x86_64/kernel/irq.c linux-2.5.52/arch/x86_64/kernel/irq.c
--- linux-2.5.52.vanilla/arch/x86_64/kernel/irq.c Thu Nov 28 01:35:59 2002
+++ linux-2.5.52/arch/x86_64/kernel/irq.c Tue Dec 24 20:33:47 2002
@@ -62,65 +62,9 @@
* 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] = { 0, &no_irq_type, NULL, 0, SPIN_LOCK_UNLOCKED}};
-
static void register_irq_proc (unsigned int irq);

-/*
- * Special irq handlers.
- */
-
-void no_action(int cpl, void *dev_id, struct pt_regs *regs) { }
-
-/*
- * 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 doesnt deserve
- * a generic callback i think.
- */
-#if 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;
#ifdef CONFIG_X86_IO_APIC
#ifdef APIC_MISMATCH_DEBUG
atomic_t irq_mis_count;
@@ -179,129 +123,6 @@
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.
- */
-int handle_IRQ_event(unsigned int irq, struct pt_regs * regs, struct irqaction * action)
-{
- int status = 1; /* Force the "do bottom halves" bit */
-
- if (!(action->flags & SA_INTERRUPT))
- local_irq_enable();
-
- do {
- status |= action->flags;
- 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 status;
-}
-
-/*
- * 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 must not 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)
-{
- 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("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
@@ -523,197 +344,6 @@
spin_unlock_irqrestore(&desc->lock,flags);
return;
}
-}
-
-/*
- * 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;
-}
-
-/*
- * 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;
}

/* this was setup_x86_irq but it seems pretty generic */
diff --minimal -urN -X /usr/share/dontdiff linux-2.5.52.vanilla/include/asm-x86_64/hw_irq.h linux-2.5.52/include/asm-x86_64/hw_irq.h
--- linux-2.5.52.vanilla/include/asm-x86_64/hw_irq.h Thu Nov 28 01:36:22 2002
+++ linux-2.5.52/include/asm-x86_64/hw_irq.h Tue Dec 24 21:56:04 2002
@@ -182,4 +182,21 @@

#endif

+/*
+ * 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.
+ */
+#ifdef CONFIG_X86_LOCAL_APIC
+#define ack_bad_irq(irq) ack_APIC_irq()
+#else
+#define ack_bad_irq(irq) do { } while (0)
+#endif
+
+/* Return a pointer to the irq descriptor for IRQ. */
+#define irq_desc(irq) (irq_desc + (irq))
+
#endif /* _ASM_HW_IRQ_H */
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