84 lines
2.4 KiB
C
84 lines
2.4 KiB
C
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/*
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* Copyright (C) 1999 Magnus Damm <kieraypc01.p.y.kie.era.ericsson.se>
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*
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* (C) Copyright 2000
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* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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#include <common.h>
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/*
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* The exception table consists of pairs of addresses: the first is the
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* address of an instruction that is allowed to fault, and the second is
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* the address at which the program should continue. No registers are
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* modified, so it is entirely up to the continuation code to figure out
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* what to do.
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*
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* All the routines below use bits of fixup code that are out of line
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* with the main instruction path. This means when everything is well,
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* we don't even have to jump over them. Further, they do not intrude
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* on our cache or tlb entries.
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*/
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struct exception_table_entry
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{
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unsigned long insn, fixup;
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};
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extern const struct exception_table_entry __start___ex_table[];
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extern const struct exception_table_entry __stop___ex_table[];
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static inline unsigned long
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search_one_table(const struct exception_table_entry *first,
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const struct exception_table_entry *last,
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unsigned long value)
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{
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while (first <= last) {
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const struct exception_table_entry *mid;
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long diff;
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mid = (last - first) / 2 + first;
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diff = mid->insn - value;
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if (diff == 0)
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return mid->fixup;
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else if (diff < 0)
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first = mid+1;
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else
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last = mid-1;
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}
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return 0;
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}
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int ex_tab_message = 1;
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unsigned long
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search_exception_table(unsigned long addr)
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{
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unsigned long ret;
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/* There is only the kernel to search. */
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ret = search_one_table(__start___ex_table, __stop___ex_table-1, addr);
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if (ex_tab_message)
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printf("Bus Fault @ 0x%08lx, fixup 0x%08lx\n", addr, ret);
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if (ret) return ret;
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return 0;
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}
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