1 /* 2 * Copyright (C) 1999 Magnus Damm <kieraypc01.p.y.kie.era.ericsson.se> 3 * 4 * (C) Copyright 2000 5 * Wolfgang Denk, DENX Software Engineering, wd@denx.de. 6 * 7 * See file CREDITS for list of people who contributed to this 8 * project. 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License as 12 * published by the Free Software Foundation; either version 2 of 13 * the License, or (at your option) any later version. 14 * 15 * This program is distributed in the hope that it will be useful, 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 * GNU General Public License for more details. 19 * 20 * You should have received a copy of the GNU General Public License 21 * along with this program; if not, write to the Free Software 22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 23 * MA 02111-1307 USA 24 */ 25 #include <common.h> 26 27 /* 28 * The exception table consists of pairs of addresses: the first is the 29 * address of an instruction that is allowed to fault, and the second is 30 * the address at which the program should continue. No registers are 31 * modified, so it is entirely up to the continuation code to figure out 32 * what to do. 33 * 34 * All the routines below use bits of fixup code that are out of line 35 * with the main instruction path. This means when everything is well, 36 * we don't even have to jump over them. Further, they do not intrude 37 * on our cache or tlb entries. 38 */ 39 40 DECLARE_GLOBAL_DATA_PTR; 41 42 struct exception_table_entry 43 { 44 unsigned long insn, fixup; 45 }; 46 47 extern const struct exception_table_entry __start___ex_table[]; 48 extern const struct exception_table_entry __stop___ex_table[]; 49 50 static inline unsigned long 51 search_one_table(const struct exception_table_entry *first, 52 const struct exception_table_entry *last, 53 unsigned long value) 54 { 55 long diff; 56 while (first <= last) { 57 diff = first->insn - value; 58 if (diff == 0) 59 return first->fixup; 60 first++; 61 } 62 63 return 0; 64 } 65 66 int ex_tab_message = 1; 67 68 unsigned long 69 search_exception_table(unsigned long addr) 70 { 71 unsigned long ret; 72 73 /* There is only the kernel to search. */ 74 ret = search_one_table(__start___ex_table, __stop___ex_table-1, addr); 75 /* if the serial port does not hang in exception, printf can be used */ 76 #if !defined(CONFIG_SYS_SERIAL_HANG_IN_EXCEPTION) 77 if (ex_tab_message) 78 debug("Bus Fault @ 0x%08lx, fixup 0x%08lx\n", addr, ret); 79 #endif 80 if (ret) return ret; 81 82 return 0; 83 } 84