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001 /* Copyright (C) 2004 David Decotigny 002 Copyright (C) 1999 Free Software Foundation, Inc. 003 004 This program is free software; you can redistribute it and/or 005 modify it under the terms of the GNU General Public License 006 as published by the Free Software Foundation; either version 2 007 of the License, or (at your option) any later version. 008 009 This program is distributed in the hope that it will be useful, 010 but WITHOUT ANY WARRANTY; without even the implied warranty of 011 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 012 GNU General Public License for more details. 013 014 You should have received a copy of the GNU General Public License 015 along with this program; if not, write to the Free Software 016 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 017 USA. 018 */ 019 #include "idt.h" 020 #include "irq.h" 021 022 #include "exception.h" 023 024 /* array of exception wrappers, defined in exception_wrappers.S */ 025 extern sos_vaddr_t sos_exception_wrapper_array[SOS_EXCEPT_NUM]; 026 027 /* arrays of exception handlers, shared with exception_wrappers.S */ 028 sos_exception_handler_t sos_exception_handler_array[SOS_EXCEPT_NUM] = 029 { NULL, }; 030 031 sos_ret_t sos_exception_subsystem_setup(void) 032 { 033 /* We inidicate that the double fault exception handler is defined, 034 and give its address. this handler is a do-nothing handler (see 035 exception_wrappers.S), and it can NOT be overriden by the 036 functions below */ 037 return sos_idt_set_handler(SOS_EXCEPT_BASE + SOS_EXCEPT_DOUBLE_FAULT, 038 (sos_vaddr_t) sos_exception_wrapper_array[SOS_EXCEPT_DOUBLE_FAULT], 039 0 /* CPL0 routine */); 040 } 041 042 043 sos_ret_t sos_exception_set_routine(int exception_number, 044 sos_exception_handler_t routine) 045 { 046 sos_ret_t retval; 047 sos_ui32_t flags; 048 049 if ((exception_number < 0) || (exception_number >= SOS_EXCEPT_NUM)) 050 return -SOS_EINVAL; 051 052 /* Double fault not supported */ 053 if (exception_number == SOS_EXCEPT_DOUBLE_FAULT) 054 return -SOS_ENOSUP; 055 056 sos_disable_IRQs(flags); 057 058 retval = SOS_OK; 059 060 /* Set the exception routine to be called by the exception wrapper */ 061 sos_exception_handler_array[exception_number] = routine; 062 063 /* If the exception is to be enabled, update the IDT with the exception 064 wrapper */ 065 if (routine != NULL) 066 retval 067 = sos_idt_set_handler(SOS_EXCEPT_BASE + exception_number, 068 (sos_vaddr_t) sos_exception_wrapper_array[exception_number], 069 0 /* CPL0 routine */); 070 else /* Disable the IDT entry */ 071 retval 072 = sos_idt_set_handler(SOS_EXCEPT_BASE + exception_number, 073 (sos_vaddr_t)NULL /* No routine => disable IDTE */, 074 0 /* don't care */); 075 076 sos_restore_IRQs(flags); 077 return retval; 078 } 079 080 081 sos_exception_handler_t sos_exception_get_routine(int exception_number) 082 { 083 if ((exception_number < 0) || (exception_number >= SOS_EXCEPT_NUM)) 084 return NULL; 085 086 /* Double fault not supported */ 087 if (exception_number == SOS_EXCEPT_DOUBLE_FAULT) 088 return NULL; 089 090 /* Expected to be atomic */ 091 return sos_exception_handler_array[exception_number]; 092 }
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