arch/powerpc/include/asm/extable.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ARCH_POWERPC_EXTABLE_H
   3 #define _ARCH_POWERPC_EXTABLE_H
   4
   5 /*
   6  * The exception table consists of pairs of relative addresses: the first is
   7  * the address of an instruction that is allowed to fault, and the second is
   8  * the address at which the program should continue.  No registers are
   9  * modified, so it is entirely up to the continuation code to figure out what
  10  * to do.
  11  *
  12  * All the routines below use bits of fixup code that are out of line with the
  13  * main instruction path.  This means when everything is well, we don't even
  14  * have to jump over them.  Further, they do not intrude on our cache or tlb
  15  * entries.
  16  */
  17
  18 #define ARCH_HAS_RELATIVE_EXTABLE
  19
  20 #ifndef __ASSEMBLY__
  21
  22 struct exception_table_entry {
  23         int insn;
  24         int fixup;
  25 };
  26
  27 static inline unsigned long extable_fixup(const struct exception_table_entry *x)
  28 {
  29         return (unsigned long)&x->fixup + x->fixup;
  30 }
  31
  32 #endif
  33
  34 /*
  35  * Helper macro for exception table entries
  36  */
  37 #define EX_TABLE(_fault, _target)               \
  38         stringify_in_c(.section __ex_table,"a";)\
  39         stringify_in_c(.balign 4;)              \
  40         stringify_in_c(.long (_fault) - . ;)    \
  41         stringify_in_c(.long (_target) - . ;)   \
  42         stringify_in_c(.previous)
  43
  44 #endif