1 #ifndef _ASM_POWERPC_CODE_PATCHING_H
2 #define _ASM_POWERPC_CODE_PATCHING_H
5 * Copyright 2008, Michael Ellerman, IBM Corporation.
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.
13 #include <asm/types.h>
14 #include <asm/ppc-opcode.h>
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);
22 #define BRANCH_SET_LINK 0x1
23 #define BRANCH_ABSOLUTE 0x2
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 int patch_instruction_site(s32 *addr, unsigned int instr);
32 int patch_branch_site(s32 *site, unsigned long target, int flags);
34 int instr_is_relative_branch(unsigned int instr);
35 int instr_is_relative_link_branch(unsigned int instr);
36 int instr_is_branch_to_addr(const unsigned int *instr, unsigned long addr);
37 unsigned long branch_target(const unsigned int *instr);
38 unsigned int translate_branch(const unsigned int *dest,
39 const unsigned int *src);
40 #ifdef CONFIG_PPC_BOOK3E_64
41 void __patch_exception(int exc, unsigned long addr);
42 #define patch_exception(exc, name) do { \
43 extern unsigned int name; \
44 __patch_exception((exc), (unsigned long)&name); \
48 #define OP_RT_RA_MASK 0xffff0000UL
49 #define LIS_R2 0x3c400000UL
50 #define ADDIS_R2_R12 0x3c4c0000UL
51 #define ADDI_R2_R2 0x38420000UL
53 static inline unsigned long ppc_function_entry(void *func)
55 #ifdef PPC64_ELF_ABI_v2
59 * A PPC64 ABIv2 function may have a local and a global entry
60 * point. We need to use the local entry point when patching
61 * functions, so identify and step over the global entry point
64 * The global entry point sequence is always of the form:
69 * A linker optimisation may convert the addis to lis:
74 if ((((*insn & OP_RT_RA_MASK) == ADDIS_R2_R12) ||
75 ((*insn & OP_RT_RA_MASK) == LIS_R2)) &&
76 ((*(insn+1) & OP_RT_RA_MASK) == ADDI_R2_R2))
77 return (unsigned long)(insn + 2);
79 return (unsigned long)func;
80 #elif defined(PPC64_ELF_ABI_v1)
82 * On PPC64 ABIv1 the function pointer actually points to the
83 * function's descriptor. The first entry in the descriptor is the
84 * address of the function text.
86 return ((func_descr_t *)func)->entry;
88 return (unsigned long)func;
92 static inline unsigned long ppc_global_function_entry(void *func)
94 #ifdef PPC64_ELF_ABI_v2
95 /* PPC64 ABIv2 the global entry point is at the address */
96 return (unsigned long)func;
98 /* All other cases there is no change vs ppc_function_entry() */
99 return ppc_function_entry(func);
105 * Some instruction encodings commonly used in dynamic ftracing
106 * and function live patching.
109 /* This must match the definition of STK_GOT in <asm/ppc_asm.h> */
110 #ifdef PPC64_ELF_ABI_v2
111 #define R2_STACK_OFFSET 24
113 #define R2_STACK_OFFSET 40
116 #define PPC_INST_LD_TOC (PPC_INST_LD | ___PPC_RT(__REG_R2) | \
117 ___PPC_RA(__REG_R1) | R2_STACK_OFFSET)
119 /* usually preceded by a mflr r0 */
120 #define PPC_INST_STD_LR (PPC_INST_STD | ___PPC_RS(__REG_R0) | \
121 ___PPC_RA(__REG_R1) | PPC_LR_STKOFF)
122 #endif /* CONFIG_PPC64 */
124 #endif /* _ASM_POWERPC_CODE_PATCHING_H */