extable.c 1.7 KB

1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162
  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. * SPDX-License-Identifier: GPL-2.0+
  8. */
  9. #include <common.h>
  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. struct exception_table_entry
  23. {
  24. unsigned long insn, fixup;
  25. };
  26. extern const struct exception_table_entry __start___ex_table[];
  27. extern const struct exception_table_entry __stop___ex_table[];
  28. static inline unsigned long
  29. search_one_table(const struct exception_table_entry *first,
  30. const struct exception_table_entry *last,
  31. unsigned long value)
  32. {
  33. long diff;
  34. while (first <= last) {
  35. diff = first->insn - value;
  36. if (diff == 0)
  37. return first->fixup;
  38. first++;
  39. }
  40. return 0;
  41. }
  42. unsigned long
  43. search_exception_table(unsigned long addr)
  44. {
  45. unsigned long ret;
  46. /* There is only the kernel to search. */
  47. ret = search_one_table(__start___ex_table, __stop___ex_table-1, addr);
  48. /* if the serial port does not hang in exception, printf can be used */
  49. #if !defined(CONFIG_SYS_SERIAL_HANG_IN_EXCEPTION)
  50. debug("Bus Fault @ 0x%08lx, fixup 0x%08lx\n", addr, ret);
  51. #endif
  52. if (ret) return ret;
  53. return 0;
  54. }