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code-patching.h
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1 #ifndef _ASM_POWERPC_CODE_PATCHING_H
2 #define _ASM_POWERPC_CODE_PATCHING_H
3 
4 /*
5  * Copyright 2008, Michael Ellerman, IBM Corporation.
6  *
7  * This program is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU General Public License
9  * as published by the Free Software Foundation; either version
10  * 2 of the License, or (at your option) any later version.
11  */
12 
13 #include <asm/types.h>
14 #include <asm/ppc-opcode.h>
15 
16 /* Flags for create_branch:
17  * "b" == create_branch(addr, target, 0);
18  * "ba" == create_branch(addr, target, BRANCH_ABSOLUTE);
19  * "bl" == create_branch(addr, target, BRANCH_SET_LINK);
20  * "bla" == create_branch(addr, target, BRANCH_ABSOLUTE | BRANCH_SET_LINK);
21  */
22 #define BRANCH_SET_LINK 0x1
23 #define BRANCH_ABSOLUTE 0x2
24 
25 unsigned int create_branch(const unsigned int *addr,
26  unsigned long target, int flags);
27 unsigned int create_cond_branch(const unsigned int *addr,
28  unsigned long target, int flags);
29 int patch_branch(unsigned int *addr, unsigned long target, int flags);
30 int patch_instruction(unsigned int *addr, unsigned int instr);
31 
32 int instr_is_relative_branch(unsigned int instr);
33 int instr_is_branch_to_addr(const unsigned int *instr, unsigned long addr);
34 unsigned long branch_target(const unsigned int *instr);
35 unsigned int translate_branch(const unsigned int *dest,
36  const unsigned int *src);
37 
38 static inline unsigned long ppc_function_entry(void *func)
39 {
40 #ifdef CONFIG_PPC64
41  /*
42  * On PPC64 the function pointer actually points to the function's
43  * descriptor. The first entry in the descriptor is the address
44  * of the function text.
45  */
46  return ((func_descr_t *)func)->entry;
47 #else
48  return (unsigned long)func;
49 #endif
50 }
51 
52 #endif /* _ASM_POWERPC_CODE_PATCHING_H */