FreeBSD/Linux Kernel Cross Reference
sys/i386/i386/intr_machdep.c

     /*-
      * Copyright (c) 2003 John Baldwin <jhb@FreeBSD.org>
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. Neither the name of the author nor the names of any co-contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     * $FreeBSD$
     */
    
    /*
     * Machine dependent interrupt code for i386.  For the i386, we have to
     * deal with different PICs.  Thus, we use the passed in vector to lookup
     * an interrupt source associated with that vector.  The interrupt source
     * describes which PIC the source belongs to and includes methods to handle
     * that source.
     */
    
    #include "opt_ddb.h"
    
    #include <sys/param.h>
    #include <sys/bus.h>
    #include <sys/interrupt.h>
    #include <sys/ktr.h>
    #include <sys/kernel.h>
    #include <sys/lock.h>
    #include <sys/mutex.h>
    #include <sys/proc.h>
    #include <sys/syslog.h>
    #include <sys/systm.h>
    #include <sys/sx.h>
    #include <machine/clock.h>
    #include <machine/intr_machdep.h>
    #include <machine/smp.h>
    #ifdef DDB
    #include <ddb/ddb.h>
    #endif
    
    #define MAX_STRAY_LOG   5
    
    typedef void (*mask_fn)(void *);
    
    static int intrcnt_index;
    static struct intsrc *interrupt_sources[NUM_IO_INTS];
    static struct sx intr_table_lock;
    static struct mtx intrcnt_lock;
    static STAILQ_HEAD(, pic) pics;
    
    #ifdef INTR_FILTER
    static void intr_eoi_src(void *arg);
    static void intr_disab_eoi_src(void *arg);
    static void intr_event_stray(void *cookie);
    #endif
    
    #ifdef SMP
    static int assign_cpu;
    
    static void     intr_assign_next_cpu(struct intsrc *isrc);
    #endif
    
    static void     intr_init(void *__dummy);
    static int      intr_pic_registered(struct pic *pic);
    static void     intrcnt_setname(const char *name, int index);
    static void     intrcnt_updatename(struct intsrc *is);
    static void     intrcnt_register(struct intsrc *is);
    
    static int
    intr_pic_registered(struct pic *pic)
    {
            struct pic *p;
    
            STAILQ_FOREACH(p, &pics, pics) {
                    if (p == pic)
                            return (1);
            }
            return (0);
    }
    
   /*
    * Register a new interrupt controller (PIC).  This is to support suspend
    * and resume where we suspend/resume controllers rather than individual
    * sources.  This also allows controllers with no active sources (such as
    * 8259As in a system using the APICs) to participate in suspend and resume.
    */
   int
   intr_register_pic(struct pic *pic)
   {
           int error;
   
           sx_xlock(&intr_table_lock);
           if (intr_pic_registered(pic))
                   error = EBUSY;
           else {
                   STAILQ_INSERT_TAIL(&pics, pic, pics);
                   error = 0;
           }
           sx_xunlock(&intr_table_lock);
           return (error);
   }
   
   /*
    * Register a new interrupt source with the global interrupt system.
    * The global interrupts need to be disabled when this function is
    * called.
    */
   int
   intr_register_source(struct intsrc *isrc)
   {
           int error, vector;
   
           KASSERT(intr_pic_registered(isrc->is_pic), ("unregistered PIC"));
           vector = isrc->is_pic->pic_vector(isrc);
           if (interrupt_sources[vector] != NULL)
                   return (EEXIST);
   #ifdef INTR_FILTER
           error = intr_event_create(&isrc->is_event, isrc, 0,
               (mask_fn)isrc->is_pic->pic_enable_source,
               intr_eoi_src, intr_disab_eoi_src, "irq%d:", vector);
   #else
           error = intr_event_create(&isrc->is_event, isrc, 0,
               (mask_fn)isrc->is_pic->pic_enable_source, "irq%d:", vector);
   #endif
           if (error)
                   return (error);
           sx_xlock(&intr_table_lock);
           if (interrupt_sources[vector] != NULL) {
                   sx_xunlock(&intr_table_lock);
                   intr_event_destroy(isrc->is_event);
                   return (EEXIST);
           }
           intrcnt_register(isrc);
           interrupt_sources[vector] = isrc;
           isrc->is_handlers = 0;
           sx_xunlock(&intr_table_lock);
           return (0);
   }
   
   struct intsrc *
   intr_lookup_source(int vector)
   {
   
           return (interrupt_sources[vector]);
   }
   
   int
   intr_add_handler(const char *name, int vector, driver_filter_t filter,
       driver_intr_t handler, void *arg, enum intr_type flags, void **cookiep)
   {
           struct intsrc *isrc;
           int error;
   
           isrc = intr_lookup_source(vector);
           if (isrc == NULL)
                   return (EINVAL);
           error = intr_event_add_handler(isrc->is_event, name, filter, handler,
               arg, intr_priority(flags), flags, cookiep);
           if (error == 0) {
                   sx_xlock(&intr_table_lock);
                   intrcnt_updatename(isrc);
                   isrc->is_handlers++;
                   if (isrc->is_handlers == 1) {
   #ifdef SMP
                           if (assign_cpu)
                                   intr_assign_next_cpu(isrc);
   #endif
                           isrc->is_pic->pic_enable_intr(isrc);
                           isrc->is_pic->pic_enable_source(isrc);
                   }
                   sx_xunlock(&intr_table_lock);
           }
           return (error);
   }
   
   int
   intr_remove_handler(void *cookie)
   {
           struct intsrc *isrc;
           int error;
   
           isrc = intr_handler_source(cookie);
           error = intr_event_remove_handler(cookie);
           if (error == 0) {
                   sx_xlock(&intr_table_lock);
                   isrc->is_handlers--;
                   if (isrc->is_handlers == 0) {
                           isrc->is_pic->pic_disable_source(isrc, PIC_NO_EOI);
                           isrc->is_pic->pic_disable_intr(isrc);
                   }
                   intrcnt_updatename(isrc);
                   sx_xunlock(&intr_table_lock);
           }
           return (error);
   }
   
   int
   intr_config_intr(int vector, enum intr_trigger trig, enum intr_polarity pol)
   {
           struct intsrc *isrc;
   
           isrc = intr_lookup_source(vector);
           if (isrc == NULL)
                   return (EINVAL);
           return (isrc->is_pic->pic_config_intr(isrc, trig, pol));
   }
   
   #ifdef INTR_FILTER
   void
   intr_execute_handlers(struct intsrc *isrc, struct trapframe *frame)
   {
           struct thread *td;
           struct intr_event *ie;
           int vector;
   
           td = curthread;
   
           /*
            * We count software interrupts when we process them.  The
            * code here follows previous practice, but there's an
            * argument for counting hardware interrupts when they're
            * processed too.
            */
           (*isrc->is_count)++;
           PCPU_INC(cnt.v_intr);
   
           ie = isrc->is_event;
   
           /*
            * XXX: We assume that IRQ 0 is only used for the ISA timer
            * device (clk).
            */
           vector = isrc->is_pic->pic_vector(isrc);
           if (vector == 0)
                   clkintr_pending = 1;
   
           if (intr_event_handle(ie, frame) != 0)
                   intr_event_stray(isrc);         
   }
   
   static void
   intr_event_stray(void *cookie)
   {
           struct intsrc *isrc;
   
           isrc = cookie;
           /*
            * For stray interrupts, mask and EOI the source, bump the
            * stray count, and log the condition.
            */
           isrc->is_pic->pic_disable_source(isrc, PIC_EOI);
           (*isrc->is_straycount)++;
           if (*isrc->is_straycount < MAX_STRAY_LOG)
                   log(LOG_ERR, "stray irq%d\n", isrc->is_pic->pic_vector(isrc));
           else if (*isrc->is_straycount == MAX_STRAY_LOG)
                   log(LOG_CRIT,
                       "too many stray irq %d's: not logging anymore\n",
                       isrc->is_pic->pic_vector(isrc));
   }
   
   static void
   intr_eoi_src(void *arg)
   {
           struct intsrc *isrc;
   
           isrc = arg;
           isrc->is_pic->pic_eoi_source(isrc);
   }
   
   static void
   intr_disab_eoi_src(void *arg)
   {
           struct intsrc *isrc;
   
           isrc = arg;
           isrc->is_pic->pic_disable_source(isrc, PIC_EOI);
   }
   #else
   void
   intr_execute_handlers(struct intsrc *isrc, struct trapframe *frame)
   {
           struct thread *td;
           struct intr_event *ie;
           struct intr_handler *ih;
           int error, vector, thread, ret;
   
           td = curthread;
   
           /*
            * We count software interrupts when we process them.  The
            * code here follows previous practice, but there's an
            * argument for counting hardware interrupts when they're
            * processed too.
            */
           (*isrc->is_count)++;
           PCPU_INC(cnt.v_intr);
   
           ie = isrc->is_event;
   
           /*
            * XXX: We assume that IRQ 0 is only used for the ISA timer
            * device (clk).
            */
           vector = isrc->is_pic->pic_vector(isrc);
           if (vector == 0)
                   clkintr_pending = 1;
   
           /*
            * For stray interrupts, mask and EOI the source, bump the
            * stray count, and log the condition.
            */
           if (ie == NULL || TAILQ_EMPTY(&ie->ie_handlers)) {
                   isrc->is_pic->pic_disable_source(isrc, PIC_EOI);
                   (*isrc->is_straycount)++;
                   if (*isrc->is_straycount < MAX_STRAY_LOG)
                           log(LOG_ERR, "stray irq%d\n", vector);
                   else if (*isrc->is_straycount == MAX_STRAY_LOG)
                           log(LOG_CRIT,
                               "too many stray irq %d's: not logging anymore\n",
                               vector);
                   return;
           }
   
           /*
            * Execute fast interrupt handlers directly.
            * To support clock handlers, if a handler registers
            * with a NULL argument, then we pass it a pointer to
            * a trapframe as its argument.
            */
           td->td_intr_nesting_level++;
           ret = 0;
           thread = 0;
           critical_enter();
           TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
                   if (ih->ih_filter == NULL) {
                           thread = 1;
                           continue;
                   }
                   CTR4(KTR_INTR, "%s: exec %p(%p) for %s", __func__,
                       ih->ih_filter, ih->ih_argument == NULL ? frame :
                       ih->ih_argument, ih->ih_name);
                   if (ih->ih_argument == NULL)
                           ret = ih->ih_filter(frame);
                   else
                           ret = ih->ih_filter(ih->ih_argument);
                   /* 
                    * Wrapper handler special handling:
                    *
                    * in some particular cases (like pccard and pccbb), 
                    * the _real_ device handler is wrapped in a couple of
                    * functions - a filter wrapper and an ithread wrapper.
                    * In this case (and just in this case), the filter wrapper 
                    * could ask the system to schedule the ithread and mask
                    * the interrupt source if the wrapped handler is composed
                    * of just an ithread handler.
                    *
                    * TODO: write a generic wrapper to avoid people rolling 
                    * their own
                    */
                   if (!thread) {
                           if (ret == FILTER_SCHEDULE_THREAD)
                                   thread = 1;
                   }
           }
   
           /*
            * If there are any threaded handlers that need to run,
            * mask the source as well as sending it an EOI.  Otherwise,
            * just send it an EOI but leave it unmasked.
            */
           if (thread)
                   isrc->is_pic->pic_disable_source(isrc, PIC_EOI);
           else
                   isrc->is_pic->pic_eoi_source(isrc);
   
           /* Schedule the ithread if needed. */
           if (thread) {
                   error = intr_event_schedule_thread(ie);
                   KASSERT(error == 0, ("bad stray interrupt"));
           }
           critical_exit();
           td->td_intr_nesting_level--;
   }
   #endif
   
   void
   intr_resume(void)
   {
           struct pic *pic;
   
           sx_xlock(&intr_table_lock);
           STAILQ_FOREACH(pic, &pics, pics) {
                   if (pic->pic_resume != NULL)
                           pic->pic_resume(pic);
           }
           sx_xunlock(&intr_table_lock);
   }
   
   void
   intr_suspend(void)
   {
           struct pic *pic;
   
           sx_xlock(&intr_table_lock);
           STAILQ_FOREACH(pic, &pics, pics) {
                   if (pic->pic_suspend != NULL)
                           pic->pic_suspend(pic);
           }
           sx_xunlock(&intr_table_lock);
   }
   
   static void
   intrcnt_setname(const char *name, int index)
   {
   
           snprintf(intrnames + (MAXCOMLEN + 1) * index, MAXCOMLEN + 1, "%-*s",
               MAXCOMLEN, name);
   }
   
   static void
   intrcnt_updatename(struct intsrc *is)
   {
   
           intrcnt_setname(is->is_event->ie_fullname, is->is_index);
   }
   
   static void
   intrcnt_register(struct intsrc *is)
   {
           char straystr[MAXCOMLEN + 1];
   
           KASSERT(is->is_event != NULL, ("%s: isrc with no event", __func__));
           mtx_lock_spin(&intrcnt_lock);
           is->is_index = intrcnt_index;
           intrcnt_index += 2;
           snprintf(straystr, MAXCOMLEN + 1, "stray irq%d",
               is->is_pic->pic_vector(is));
           intrcnt_updatename(is);
           is->is_count = &intrcnt[is->is_index];
           intrcnt_setname(straystr, is->is_index + 1);
           is->is_straycount = &intrcnt[is->is_index + 1];
           mtx_unlock_spin(&intrcnt_lock);
   }
   
   void
   intrcnt_add(const char *name, u_long **countp)
   {
   
           mtx_lock_spin(&intrcnt_lock);
           *countp = &intrcnt[intrcnt_index];
           intrcnt_setname(name, intrcnt_index);
           intrcnt_index++;
           mtx_unlock_spin(&intrcnt_lock);
   }
   
   static void
   intr_init(void *dummy __unused)
   {
   
           intrcnt_setname("???", 0);
           intrcnt_index = 1;
           STAILQ_INIT(&pics);
           sx_init(&intr_table_lock, "intr sources");
           mtx_init(&intrcnt_lock, "intrcnt", NULL, MTX_SPIN);
   }
   SYSINIT(intr_init, SI_SUB_INTR, SI_ORDER_FIRST, intr_init, NULL)
   
   #ifdef DDB
   /*
    * Dump data about interrupt handlers
    */
   DB_SHOW_COMMAND(irqs, db_show_irqs)
   {
           struct intsrc **isrc;
           int i, verbose;
   
           if (strcmp(modif, "v") == 0)
                   verbose = 1;
           else
                   verbose = 0;
           isrc = interrupt_sources;
           for (i = 0; i < NUM_IO_INTS && !db_pager_quit; i++, isrc++)
                   if (*isrc != NULL)
                           db_dump_intr_event((*isrc)->is_event, verbose);
   }
   #endif
   
   #ifdef SMP
   /*
    * Support for balancing interrupt sources across CPUs.  For now we just
    * allocate CPUs round-robin.
    */
   
   /* The BSP is always a valid target. */
   static cpumask_t intr_cpus = (1 << 0);
   static int current_cpu, num_cpus = 1;
   
   static void
   intr_assign_next_cpu(struct intsrc *isrc)
   {
           struct pic *pic;
           u_int apic_id;
   
           /*
            * Assign this source to a local APIC in a round-robin fashion.
            */
           pic = isrc->is_pic;
           apic_id = cpu_apic_ids[current_cpu];
           pic->pic_assign_cpu(isrc, apic_id);
           do {
                   current_cpu++;
                   if (current_cpu >= num_cpus)
                           current_cpu = 0;
           } while (!(intr_cpus & (1 << current_cpu)));
   }
   
   /*
    * Add a CPU to our mask of valid CPUs that can be destinations of
    * interrupts.
    */
   void
   intr_add_cpu(u_int cpu)
   {
   
           if (cpu >= MAXCPU)
                   panic("%s: Invalid CPU ID", __func__);
           if (bootverbose)
                   printf("INTR: Adding local APIC %d as a target\n",
                       cpu_apic_ids[cpu]);
   
           intr_cpus |= (1 << cpu);
           num_cpus++;
   }
   
   /*
    * Distribute all the interrupt sources among the available CPUs once the
    * AP's have been launched.
    */
   static void
   intr_shuffle_irqs(void *arg __unused)
   {
           struct intsrc *isrc;
           int i;
   
           /* Don't bother on UP. */
           if (num_cpus <= 1)
                   return;
   
           /* Round-robin assign a CPU to each enabled source. */
           sx_xlock(&intr_table_lock);
           assign_cpu = 1;
           for (i = 0; i < NUM_IO_INTS; i++) {
                   isrc = interrupt_sources[i];
                   if (isrc != NULL && isrc->is_handlers > 0)
                           intr_assign_next_cpu(isrc);
           }
           sx_xunlock(&intr_table_lock);
   }
   SYSINIT(intr_shuffle_irqs, SI_SUB_SMP, SI_ORDER_SECOND, intr_shuffle_irqs, NULL)
   #endif

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