arch/all-unix/kernel/kernel_intr.c

   1 /*
   2     Copyright © 1995-2017, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #include <aros/atomic.h>
   7 #include <exec/execbase.h>
   8 #include <hardware/intbits.h>
   9 #include <proto/exec.h>
  10
  11 #include <kernel_base.h>
  12 #include <kernel_debug.h>
  13 #include <kernel_interrupts.h>
  14 #include <kernel_intr.h>
  15 #include <kernel_globals.h>
  16 #include <kernel_scheduler.h>
  17 #include <kernel_syscall.h>
  18 #include "kernel_intern.h"
  19 #include "kernel_unix.h"
  20
  21 #define D(x)
  22
  23 /*
  24  * Leave the interrupt. This function receives the interrupt register frame
  25  * and runs task scheduler if needed.
  26  *
  27  * You should call it only if you're returning to user mode (i.e. not from
  28  * within nested interrupt).
  29  *
  30  * It relies on CPU-specific cpu_Switch() and cpu_Dispatch() implementations
  31  * which save and restore CPU context. cpu_Dispatch() is allowed just to
  32  * jump to the saved context and not return here.
  33  */
  34 void core_ExitInterrupt(regs_t *regs)
  35 {
  36     /* Soft interrupt requested? It's high time to do it */
  37     if (SysBase->SysFlags & SFF_SoftInt)
  38         core_Cause(INTB_SOFTINT, 1L << INTB_SOFTINT);
  39
  40     /* If task switching is disabled, do nothing */
  41     if (SysBase->TDNestCnt < 0)
  42     {
  43         /*
  44          * Do not disturb task if it's not necessary.
  45          * Reschedule only if switch pending flag is set. Exit otherwise.
  46          */
  47         if (SysBase->AttnResched & ARF_AttnSwitch)
  48         {
  49             /* Run task scheduling sequence */
  50             if (core_Schedule())
  51             {
  52                 cpu_Switch(regs);
  53                 cpu_Dispatch(regs);
  54             }
  55         }
  56     }
  57 }
  58
  59 /*
  60  * We do not have enough user-defined signals to map
  61  * them to four required syscalls (CAUSE, SCHEDULE,
  62  * SWITCH, DISPATCH). We get around this by assigning
  63  * CAUSE to SIGUSR2 and others to SIGUSR1.
  64  *
  65  * What action is to be taken upon SIGUSR1 can be
  66  * figured out by looking at caller task's state.
  67  * exec.library calls KrnDispatch() only after task
  68  * has been actually disposed, with state set to TS_REMOVED.
  69  * Similarly, KrnSwitch() is called only in Wait(), after
  70  * setting state to TS_WAIT. In other cases it's KrnSchedule().
  71  */
  72 void core_SysCall(int sig, regs_t *regs)
  73 {
  74     struct KernelBase *KernelBase = getKernelBase();
  75     struct Task *task = SysBase->ThisTask;
  76
  77     D(bug("[KRN] %s()\n", __func__));
  78
  79     SUPERVISOR_ENTER;
  80
  81     krnRunIRQHandlers(KernelBase, sig);
  82
  83     switch(task->tc_State)
  84     {
  85     /* A running task needs to be put into TaskReady list first. It's SC_SCHEDULE. */
  86     case TS_RUN:
  87         if (!core_Schedule())
  88             break;
  89
  90     /* If the task is already in some list with appropriate state, it's SC_SWITCH */
  91     case TS_REMOVED:
  92     case TS_READY:
  93     case TS_WAIT:
  94         cpu_Switch(regs);
  95
  96     /* If the task is removed, it's simply SC_DISPATCH */
  97     case TS_INVALID:
  98         cpu_Dispatch(regs);
  99         break;
 100
 101     /* Special state is used for returning from exception */
 102     case TS_EXCEPT:
 103         cpu_DispatchContext(task, regs, KernelBase->kb_PlatformData);
 104         break;
 105     }
 106
 107     SUPERVISOR_LEAVE;
 108 }