rom/kernel/addexceptionhandler.c

   1 /*
   2     Copyright © 1995-2013, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc:
   6 */
   7
   8 #include <aros/kernel.h>
   9 #include <proto/exec.h>
  10
  11 #include <inttypes.h>
  12
  13 #include <kernel_base.h>
  14 #include <kernel_cpu.h>
  15 #include <kernel_debug.h>
  16 #include <kernel_interrupts.h>
  17 #include <kernel_objects.h>
  18
  19 /* We use own implementation of bug(), so we don't need aros/debug.h */
  20 #define D(x)
  21
  22 /*****************************************************************************
  23
  24     NAME */
  25 #include <proto/kernel.h>
  26
  27         AROS_LH4(void *, KrnAddExceptionHandler,
  28
  29 /*  SYNOPSIS */
  30         AROS_LHA(uint8_t, num, D0),
  31         AROS_LHA(exhandler_t *, handler, A0),
  32         AROS_LHA(void *, handlerData, A1),
  33         AROS_LHA(void *, handlerData2, A2),
  34
  35 /*  LOCATION */
  36         struct KernelBase *, KernelBase, 14, Kernel)
  37
  38 /*  FUNCTION
  39         Add a raw CPU exception handler to the chain of handlers.
  40
  41     INPUTS
  42         num          - CPU-specific exception number
  43         handler      - Pointer to a handler function
  44         handlerData,
  45         handlerData2 - User-defined data which is passed to the
  46                        handler.
  47
  48           Handler function uses a C calling convention and must be
  49           declared as follows:
  50
  51           int ExceptionHandler(void *ctx, void *handlerData, void *handlerData2)
  52
  53           handlerData and handlerData2 will be values passed to the
  54           KrnAddExceptionHandler() function. ctx is a CPU context handle.
  55           Consider this parameter private and reserved for now.
  56
  57           Exception handler should return nonzero value if it processes the
  58           exception and wants to continue program execution. Otherwise it should
  59           return zero. If all exception handlers in the chain return zero, the
  60           exception will be passed on to exec.library trap handler pointed to
  61           by tc_TrapCode field of task structure.
  62
  63     RESULT
  64         An opaque handle that can be used for handler removal or NULL in case
  65         of failure (like unsupported exception number).
  66
  67     NOTES
  68         The specification of this function is preliminary and subject to change.
  69         Consider it private for now.
  70
  71     EXAMPLE
  72
  73     BUGS
  74
  75     SEE ALSO
  76         KrnRemExceptionHandler()
  77
  78     INTERNALS
  79
  80 ******************************************************************************/
  81 {
  82     AROS_LIBFUNC_INIT
  83
  84     struct IntrNode *handle = NULL;
  85     D(bug("[KRN] KrnAddExceptionHandler(%02x, %012p, %012p, %012p):\n", num, handler, handlerData, handlerData2));
  86
  87     if (num < EXCEPTIONS_COUNT)
  88     {
  89         /* Go to supervisor mode */
  90         (void)goSuper();
  91
  92         /* Allocate protected memory, accessible only in supervisor mode */
  93         handle = krnAllocIntrNode();
  94         D(bug("[KRN] handle=%012p\n", handle));
  95
  96         if (handle)
  97         {
  98             handle->in_Handler = handler;
  99             handle->in_HandlerData = handlerData;
 100             handle->in_HandlerData2 = handlerData2;
 101             handle->in_type = it_exception;
 102             handle->in_nr = num;
 103
 104             Disable();
 105             ADDHEAD(&KernelBase->kb_Exceptions[num], &handle->in_Node);
 106             Enable();
 107         }
 108
 109         goUser();
 110     }
 111
 112     return handle;
 113
 114     AROS_LIBFUNC_EXIT
 115 }
 116
 117 /* Run exception handlers and accumulate return value */
 118 int krnRunExceptionHandlers(struct KernelBase *KernelBase, uint8_t exception, void *ctx)
 119 {
 120     struct IntrNode *in, *in2;
 121     int ret = 0;
 122
 123     /* We can be called really early. Protect against this. */
 124     if (!KernelBase)
 125         return 0;
 126
 127     ForeachNodeSafe(&KernelBase->kb_Exceptions[exception], in, in2)
 128     {
 129         exhandler_t h = in->in_Handler;
 130
 131         if (h)
 132             ret |= h(ctx, in->in_HandlerData, in->in_HandlerData2);
 133     }
 134
 135     return ret;
 136 }