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