LXR uboot/arch/powerpc/lib/extable.c

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Copyright (C) 1999  Magnus Damm <kieraypc01.p.y.kie.era.ericsson.se>
   4 *
   5 * (C) Copyright 2000
   6 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   7 */
   8#include <common.h>
   9
  10/*
  11 * The exception table consists of pairs of addresses: the first is the
  12 * address of an instruction that is allowed to fault, and the second is
  13 * the address at which the program should continue.  No registers are
  14 * modified, so it is entirely up to the continuation code to figure out
  15 * what to do.
  16 *
  17 * All the routines below use bits of fixup code that are out of line
  18 * with the main instruction path.  This means when everything is well,
  19 * we don't even have to jump over them.  Further, they do not intrude
  20 * on our cache or tlb entries.
  21 */
  22
  23struct exception_table_entry
  24{
  25        unsigned long insn, fixup;
  26};
  27
  28extern const struct exception_table_entry __start___ex_table[];
  29extern const struct exception_table_entry __stop___ex_table[];
  30
  31static inline unsigned long
  32search_one_table(const struct exception_table_entry *first,
  33                 const struct exception_table_entry *last,
  34                 unsigned long value)
  35{
  36        long diff;
  37        while (first <= last) {
  38                diff = first->insn - value;
  39                if (diff == 0)
  40                        return first->fixup;
  41                first++;
  42        }
  43
  44        return 0;
  45}
  46
  47unsigned long
  48search_exception_table(unsigned long addr)
  49{
  50        unsigned long ret;
  51
  52        /* There is only the kernel to search.  */
  53        ret = search_one_table(__start___ex_table, __stop___ex_table-1, addr);
  54        /* if the serial port does not hang in exception, printf can be used */
  55#if !defined(CONFIG_SYS_SERIAL_HANG_IN_EXCEPTION)
  56        debug("Bus Fault @ 0x%08lx, fixup 0x%08lx\n", addr, ret);
  57#endif
  58        if (ret) return ret;
  59
  60        return 0;
  61}
  62