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wdenkfe8c2802002-11-03 00:38:21 +00001/*
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
roy zang9d27b3a2006-12-04 17:56:59 +080040DECLARE_GLOBAL_DATA_PTR;
41
wdenkfe8c2802002-11-03 00:38:21 +000042struct exception_table_entry
43{
44 unsigned long insn, fixup;
45};
46
47extern const struct exception_table_entry __start___ex_table[];
48extern const struct exception_table_entry __stop___ex_table[];
49
50static inline unsigned long
51search_one_table(const struct exception_table_entry *first,
52 const struct exception_table_entry *last,
53 unsigned long value)
54{
Zang Roy-r619111b305bd2007-05-09 08:10:57 +080055 long diff;
56 if ((ulong) first > CFG_MONITOR_BASE) {
57 /* exception occurs in FLASH, before u-boot relocation.
58 * No relocation offset is needed.
59 */
60 while (first <= last) {
61 diff = first->insn - value;
roy zangc9c1eee2006-12-01 19:01:25 +080062 if (diff == 0)
Zang Roy-r619111b305bd2007-05-09 08:10:57 +080063 return first->fixup;
64 first++;
roy zangc9c1eee2006-12-01 19:01:25 +080065 }
Zang Roy-r619111b305bd2007-05-09 08:10:57 +080066 } else {
67 /* exception occurs in RAM, after u-boot relocation.
68 * A relocation offset should be added.
69 */
70 while (first <= last) {
71 diff = (first->insn + gd->reloc_off) - value;
72 if (diff == 0)
73 return (first->fixup + gd->reloc_off);
74 first++;
75 }
wdenk8bde7f72003-06-27 21:31:46 +000076 }
77 return 0;
wdenkfe8c2802002-11-03 00:38:21 +000078}
79
80int ex_tab_message = 1;
81
82unsigned long
83search_exception_table(unsigned long addr)
84{
85 unsigned long ret;
86
87 /* There is only the kernel to search. */
88 ret = search_one_table(__start___ex_table, __stop___ex_table-1, addr);
roy zangc9c1eee2006-12-01 19:01:25 +080089 /* if the serial port does not hang in exception, printf can be used */
roy zang4c527832006-11-02 18:49:51 +080090#if !defined(CFG_SERIAL_HANG_IN_EXCEPTION)
wdenkfe8c2802002-11-03 00:38:21 +000091 if (ex_tab_message)
Grzegorz Bernackic9240982007-07-31 18:51:48 +020092 debug("Bus Fault @ 0x%08lx, fixup 0x%08lx\n", addr, ret);
roy zang4c527832006-11-02 18:49:51 +080093#endif
wdenkfe8c2802002-11-03 00:38:21 +000094 if (ret) return ret;
95
96 return 0;
97}