#include <asm/bitops.h>
#include <asm/flushtlb.h>
#include <xen/delay.h>
-#include <xen/timex.h>
#include <xen/perfc.h>
#include <asm/smpboot.h>
irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned =
{ [0 ... NR_IRQS-1] = { 0, &no_irq_type, NULL, 0, SPIN_LOCK_UNLOCKED}};
-#ifdef CONFIG_SMP
-/* NB. XXX We'll want some way of fiddling with this from DOM0. */
-unsigned long irq_affinity [NR_IRQS] = { [0 ... NR_IRQS-1] = ~0UL };
-#endif
-
static void __do_IRQ_guest(int irq);
/*
* Generic, controller-independent functions:
*/
-/*
- * Global interrupt locks for SMP. Allow interrupts to come in on any
- * CPU, yet make cli/sti act globally to protect critical regions..
- */
-
-#ifdef CONFIG_SMP
-unsigned char global_irq_holder = 0xff;
-unsigned volatile long global_irq_lock; /* pendantic: long for set_bit --RR */
-
-#define MAXCOUNT 100000000
-
-/*
- * I had a lockup scenario where a tight loop doing
- * spin_unlock()/spin_lock() on CPU#1 was racing with
- * spin_lock() on CPU#0. CPU#0 should have noticed spin_unlock(), but
- * apparently the spin_unlock() information did not make it
- * through to CPU#0 ... nasty, is this by design, do we have to limit
- * 'memory update oscillation frequency' artificially like here?
- *
- * Such 'high frequency update' races can be avoided by careful design, but
- * some of our major constructs like spinlocks use similar techniques,
- * it would be nice to clarify this issue. Set this define to 0 if you
- * want to check whether your system freezes. I suspect the delay done
- * by SYNC_OTHER_CORES() is in correlation with 'snooping latency', but
- * i thought that such things are guaranteed by design, since we use
- * the 'LOCK' prefix.
- */
-#define SUSPECTED_CPU_OR_CHIPSET_BUG_WORKAROUND 0
-
-#if SUSPECTED_CPU_OR_CHIPSET_BUG_WORKAROUND
-# define SYNC_OTHER_CORES(x) udelay(x+1)
-#else
-/*
- * We have to allow irqs to arrive between __sti and __cli
- */
-# define SYNC_OTHER_CORES(x) __asm__ __volatile__ ("nop")
-#endif
-
-static inline void wait_on_irq(int cpu)
-{
- for (;;) {
-
- /*
- * Wait until all interrupts are gone. Wait
- * for bottom half handlers unless we're
- * already executing in one..
- */
- if (!irqs_running())
- if (local_bh_count(cpu))
- break;
-
- /* Duh, we have to loop. Release the lock to avoid deadlocks */
- clear_bit(0,&global_irq_lock);
-
- for (;;) {
- __sti();
- SYNC_OTHER_CORES(cpu);
- __cli();
- if (irqs_running())
- continue;
- if (global_irq_lock)
- continue;
- if (!local_bh_count(cpu))
- continue;
- if (!test_and_set_bit(0,&global_irq_lock))
- break;
- }
- }
-}
-
-/*
- * This is called when we want to synchronize with
- * interrupts. We may for example tell a device to
- * stop sending interrupts: but to make sure there
- * are no interrupts that are executing on another
- * CPU we need to call this function.
- */
-void synchronize_irq(void)
-{
- if (irqs_running()) {
- /* Stupid approach */
- cli();
- sti();
- }
-}
-
-static inline void get_irqlock(int cpu)
-{
- if (test_and_set_bit(0,&global_irq_lock)) {
- /* do we already hold the lock? */
- if ((unsigned char) cpu == global_irq_holder)
- return;
- /* Uhhuh.. Somebody else got it. Wait.. */
- do {
- do {
- rep_nop();
- } while (test_bit(0,&global_irq_lock));
- } while (test_and_set_bit(0,&global_irq_lock));
- }
- /*
- * We also to make sure that nobody else is running
- * in an interrupt context.
- */
- wait_on_irq(cpu);
-
- /*
- * Ok, finally..
- */
- global_irq_holder = cpu;
-}
-
-#define EFLAGS_IF_SHIFT 9
-
-/*
- * A global "cli()" while in an interrupt context
- * turns into just a local cli(). Interrupts
- * should use spinlocks for the (very unlikely)
- * case that they ever want to protect against
- * each other.
- *
- * If we already have local interrupts disabled,
- * this will not turn a local disable into a
- * global one (problems with spinlocks: this makes
- * save_flags+cli+sti usable inside a spinlock).
- */
-void __global_cli(void)
-{
- unsigned int flags;
-
- __save_flags(flags);
- if (flags & (1 << EFLAGS_IF_SHIFT)) {
- int cpu = smp_processor_id();
- __cli();
- if (!local_irq_count(cpu))
- get_irqlock(cpu);
- }
-}
-
-void __global_sti(void)
-{
- int cpu = smp_processor_id();
-
- if (!local_irq_count(cpu))
- release_irqlock(cpu);
- __sti();
-}
-
-/*
- * SMP flags value to restore to:
- * 0 - global cli
- * 1 - global sti
- * 2 - local cli
- * 3 - local sti
- */
-unsigned long __global_save_flags(void)
-{
- int retval;
- int local_enabled;
- unsigned long flags;
- int cpu = smp_processor_id();
-
- __save_flags(flags);
- local_enabled = (flags >> EFLAGS_IF_SHIFT) & 1;
- /* default to local */
- retval = 2 + local_enabled;
-
- /* check for global flags if we're not in an interrupt */
- if (!local_irq_count(cpu)) {
- if (local_enabled)
- retval = 1;
- if (global_irq_holder == cpu)
- retval = 0;
- }
- return retval;
-}
-
-void __global_restore_flags(unsigned long flags)
-{
- switch (flags) {
- case 0:
- __global_cli();
- break;
- case 1:
- __global_sti();
- break;
- case 2:
- __cli();
- break;
- case 3:
- __sti();
- break;
- default:
- printk("global_restore_flags: %08lx (%08lx)\n",
- flags, (&flags)[-1]);
- }
-}
-
-#endif
-
/*
* This should really return information about whether
* we should do bottom half handling etc. Right now we
}
}
-/*
- * 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 spinlock_t probe_sem = SPIN_LOCK_UNLOCKED;
-
-/**
- * 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 s=0, e=0;
-
- spin_lock(&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 (20ms delay). */
- rdtscl(s);
- do {
- synchronize_irq();
- rdtscl(e);
- } while ( ((e-s)/ticks_per_usec) < 20000 );
-
- /*
- * 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 (100ms delay).
- */
- rdtscl(s);
- do {
- synchronize_irq();
- rdtscl(e);
- } while ( ((e-s)/ticks_per_usec) < 100000 );
-
- /*
- * 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);
- }
- spin_unlock(&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);
- }
- spin_unlock(&probe_sem);
-
- if (nr_irqs > 1)
- irq_found = -irq_found;
- return irq_found;
-}
-
-/* this was setup_x86_irq but it seems pretty generic */
int setup_irq(unsigned int irq, struct irqaction * new)
{
int shared = 0;
projects / xen.git / commitdiff