kernel/system/do_irqctl.c

   1 /* The kernel call implemented in this file:
   2  *   m_type:    SYS_IRQCTL
   3  *
   4  * The parameters for this kernel call are:
   5  *    m5_s1:    IRQ_REQUEST     (control operation to perform)
   6  *    m5_s2:    IRQ_VECTOR      (irq line that must be controlled)
   7  *    m5_i1:    IRQ_POLICY      (irq policy allows reenabling interrupts)
   8  *    m5_l3:    IRQ_HOOK_ID     (provides index to be returned on interrupt)
   9  *      ,,          ,,          (returns index of irq hook assigned at kernel)
  10  */
  11
  12 #include "../system.h"
  13
  14 #include <minix/endpoint.h>
  15
  16 #if USE_IRQCTL
  17
  18 FORWARD _PROTOTYPE(int generic_handler, (irq_hook_t *hook));
  19
  20 /*===========================================================================*
  21  *                              do_irqctl                                    *
  22  *===========================================================================*/
  23 PUBLIC int do_irqctl(struct proc * caller, message * m_ptr)
  24 {
  25   /* Dismember the request message. */
  26   int irq_vec;
  27   int irq_hook_id;
  28   int notify_id;
  29   int r = OK;
  30   int i;
  31   irq_hook_t *hook_ptr;
  32   struct priv *privp;
  33
  34   /* Hook identifiers start at 1 and end at NR_IRQ_HOOKS. */
  35   irq_hook_id = (unsigned) m_ptr->IRQ_HOOK_ID - 1;
  36   irq_vec = (unsigned) m_ptr->IRQ_VECTOR;
  37
  38   /* See what is requested and take needed actions. */
  39   switch(m_ptr->IRQ_REQUEST) {
  40
  41   /* Enable or disable IRQs. This is straightforward. */
  42   case IRQ_ENABLE:
  43   case IRQ_DISABLE:
  44       if (irq_hook_id >= NR_IRQ_HOOKS || irq_hook_id < 0 ||
  45           irq_hooks[irq_hook_id].proc_nr_e == NONE) return(EINVAL);
  46       if (irq_hooks[irq_hook_id].proc_nr_e != m_ptr->m_source) return(EPERM);
  47       if (m_ptr->IRQ_REQUEST == IRQ_ENABLE) {
  48           enable_irq(&irq_hooks[irq_hook_id]);
  49       }
  50       else
  51           disable_irq(&irq_hooks[irq_hook_id]);
  52       break;
  53
  54   /* Control IRQ policies. Set a policy and needed details in the IRQ table.
  55    * This policy is used by a generic function to handle hardware interrupts.
  56    */
  57   case IRQ_SETPOLICY:
  58
  59       /* Check if IRQ line is acceptable. */
  60       if (irq_vec < 0 || irq_vec >= NR_IRQ_VECTORS) return(EINVAL);
  61
  62       privp= priv(caller);
  63       if (!privp)
  64       {
  65         kprintf("do_irqctl: no priv structure!\n");
  66         return EPERM;
  67       }
  68       if (privp->s_flags & CHECK_IRQ)
  69       {
  70         for (i= 0; i<privp->s_nr_irq; i++)
  71         {
  72                 if (irq_vec == privp->s_irq_tab[i])
  73                         break;
  74         }
  75         if (i >= privp->s_nr_irq)
  76         {
  77                 kprintf(
  78                 "do_irqctl: IRQ check failed for proc %d, IRQ %d\n",
  79                         m_ptr->m_source, irq_vec);
  80                 return EPERM;
  81         }
  82     }
  83
  84       /* Find a free IRQ hook for this mapping. */
  85       hook_ptr = NULL;
  86       for (irq_hook_id=0; irq_hook_id<NR_IRQ_HOOKS; irq_hook_id++) {
  87           if (irq_hooks[irq_hook_id].proc_nr_e == NONE) {
  88               hook_ptr = &irq_hooks[irq_hook_id];       /* free hook */
  89               break;
  90           }
  91       }
  92       if (hook_ptr == NULL) return(ENOSPC);
  93
  94       /* When setting a policy, the caller must provide an identifier that
  95        * is returned on the notification message if a interrupt occurs.
  96        */
  97       notify_id = (unsigned) m_ptr->IRQ_HOOK_ID;
  98       if (notify_id > CHAR_BIT * sizeof(irq_id_t) - 1) return(EINVAL);
  99
 100       /* Install the handler. */
 101       hook_ptr->proc_nr_e = m_ptr->m_source;    /* process to notify */
 102       hook_ptr->notify_id = notify_id;          /* identifier to pass */
 103       hook_ptr->policy = m_ptr->IRQ_POLICY;     /* policy for interrupts */
 104       put_irq_handler(hook_ptr, irq_vec, generic_handler);
 105
 106       /* Return index of the IRQ hook in use. */
 107       m_ptr->IRQ_HOOK_ID = irq_hook_id + 1;
 108       break;
 109
 110   case IRQ_RMPOLICY:
 111       if (irq_hook_id < 0 || irq_hook_id >= NR_IRQ_HOOKS ||
 112                irq_hooks[irq_hook_id].proc_nr_e == NONE) {
 113            return(EINVAL);
 114       } else if (m_ptr->m_source != irq_hooks[irq_hook_id].proc_nr_e) {
 115            return(EPERM);
 116       }
 117       /* Remove the handler and return. */
 118       rm_irq_handler(&irq_hooks[irq_hook_id]);
 119       break;
 120
 121   default:
 122       r = EINVAL;                               /* invalid IRQ_REQUEST */
 123   }
 124   return(r);
 125 }
 126
 127 /*===========================================================================*
 128  *                             generic_handler                               *
 129  *===========================================================================*/
 130 PRIVATE int generic_handler(hook)
 131 irq_hook_t *hook;
 132 {
 133 /* This function handles hardware interrupt in a simple and generic way. All
 134  * interrupts are transformed into messages to a driver. The IRQ line will be
 135  * reenabled if the policy says so.
 136  */
 137   int proc_nr;
 138
 139   vmassert(intr_disabled());
 140
 141   /* As a side-effect, the interrupt handler gathers random information by
 142    * timestamping the interrupt events. This is used for /dev/random.
 143    */
 144   get_randomness(&krandom, hook->irq);
 145
 146   /* Check if the handler is still alive.
 147    * If it's dead, this should never happen, as processes that die
 148    * automatically get their interrupt hooks unhooked.
 149    */
 150   if(!isokendpt(hook->proc_nr_e, &proc_nr))
 151      minix_panic("invalid interrupt handler", hook->proc_nr_e);
 152
 153   /* Add a bit for this interrupt to the process' pending interrupts. When
 154    * sending the notification message, this bit map will be magically set
 155    * as an argument.
 156    */
 157   priv(proc_addr(proc_nr))->s_int_pending |= (1 << hook->notify_id);
 158
 159   /* Build notification message and return. */
 160   vmassert(intr_disabled());
 161   mini_notify(proc_addr(HARDWARE), hook->proc_nr_e);
 162   return(hook->policy & IRQ_REENABLE);
 163 }
 164
 165 #endif /* USE_IRQCTL */
 166