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>
15 #include <linux/string.h>
16 #include <linux/kallsyms.h>
17 #include <asm/asm-compat.h>
19 /* Flags for create_branch:
20 * "b" == create_branch(addr, target, 0);
21 * "ba" == create_branch(addr, target, BRANCH_ABSOLUTE);
22 * "bl" == create_branch(addr, target, BRANCH_SET_LINK);
23 * "bla" == create_branch(addr, target, BRANCH_ABSOLUTE | BRANCH_SET_LINK);
25 #define BRANCH_SET_LINK 0x1
26 #define BRANCH_ABSOLUTE 0x2
28 bool is_offset_in_branch_range(long offset);
29 unsigned int create_branch(const unsigned int *addr,
30 unsigned long target, int flags);
31 unsigned int create_cond_branch(const unsigned int *addr,
32 unsigned long target, int flags);
33 int patch_branch(unsigned int *addr, unsigned long target, int flags);
34 int patch_instruction(unsigned int *addr, unsigned int instr);
35 int raw_patch_instruction(unsigned int *addr, unsigned int instr);
37 static inline unsigned long patch_site_addr(s32 *site)
39 return (unsigned long)site + *site;
42 static inline int patch_instruction_site(s32 *site, unsigned int instr)
44 return patch_instruction((unsigned int *)patch_site_addr(site), instr);
47 static inline int patch_branch_site(s32 *site, unsigned long target, int flags)
49 return patch_branch((unsigned int *)patch_site_addr(site), target, flags);
52 static inline int modify_instruction(unsigned int *addr, unsigned int clr,
55 return patch_instruction(addr, (*addr & ~clr) | set);
58 static inline int modify_instruction_site(s32 *site, unsigned int clr, unsigned int set)
60 return modify_instruction((unsigned int *)patch_site_addr(site), clr, set);
63 int instr_is_relative_branch(unsigned int instr);
64 int instr_is_relative_link_branch(unsigned int instr);
65 int instr_is_branch_to_addr(const unsigned int *instr, unsigned long addr);
66 unsigned long branch_target(const unsigned int *instr);
67 unsigned int translate_branch(const unsigned int *dest,
68 const unsigned int *src);
69 extern bool is_conditional_branch(unsigned int instr);
70 #ifdef CONFIG_PPC_BOOK3E_64
71 void __patch_exception(int exc, unsigned long addr);
72 #define patch_exception(exc, name) do { \
73 extern unsigned int name; \
74 __patch_exception((exc), (unsigned long)&name); \
78 #define OP_RT_RA_MASK 0xffff0000UL
79 #define LIS_R2 0x3c020000UL
80 #define ADDIS_R2_R12 0x3c4c0000UL
81 #define ADDI_R2_R2 0x38420000UL
83 static inline unsigned long ppc_function_entry(void *func)
85 #ifdef PPC64_ELF_ABI_v2
89 * A PPC64 ABIv2 function may have a local and a global entry
90 * point. We need to use the local entry point when patching
91 * functions, so identify and step over the global entry point
94 * The global entry point sequence is always of the form:
99 * A linker optimisation may convert the addis to lis:
104 if ((((*insn & OP_RT_RA_MASK) == ADDIS_R2_R12) ||
105 ((*insn & OP_RT_RA_MASK) == LIS_R2)) &&
106 ((*(insn+1) & OP_RT_RA_MASK) == ADDI_R2_R2))
107 return (unsigned long)(insn + 2);
109 return (unsigned long)func;
110 #elif defined(PPC64_ELF_ABI_v1)
112 * On PPC64 ABIv1 the function pointer actually points to the
113 * function's descriptor. The first entry in the descriptor is the
114 * address of the function text.
116 return ((func_descr_t *)func)->entry;
118 return (unsigned long)func;
122 static inline unsigned long ppc_global_function_entry(void *func)
124 #ifdef PPC64_ELF_ABI_v2
125 /* PPC64 ABIv2 the global entry point is at the address */
126 return (unsigned long)func;
128 /* All other cases there is no change vs ppc_function_entry() */
129 return ppc_function_entry(func);
134 * Wrapper around kallsyms_lookup() to return function entry address:
135 * - For ABIv1, we lookup the dot variant.
136 * - For ABIv2, we return the local entry point.
138 static inline unsigned long ppc_kallsyms_lookup_name(const char *name)
141 #ifdef PPC64_ELF_ABI_v1
142 /* check for dot variant */
143 char dot_name[1 + KSYM_NAME_LEN];
144 bool dot_appended = false;
146 if (strnlen(name, KSYM_NAME_LEN) >= KSYM_NAME_LEN)
149 if (name[0] != '.') {
152 strlcat(dot_name, name, sizeof(dot_name));
156 strlcat(dot_name, name, sizeof(dot_name));
158 addr = kallsyms_lookup_name(dot_name);
159 if (!addr && dot_appended)
160 /* Let's try the original non-dot symbol lookup */
161 addr = kallsyms_lookup_name(name);
162 #elif defined(PPC64_ELF_ABI_v2)
163 addr = kallsyms_lookup_name(name);
165 addr = ppc_function_entry((void *)addr);
167 addr = kallsyms_lookup_name(name);
174 * Some instruction encodings commonly used in dynamic ftracing
175 * and function live patching.
178 /* This must match the definition of STK_GOT in <asm/ppc_asm.h> */
179 #ifdef PPC64_ELF_ABI_v2
180 #define R2_STACK_OFFSET 24
182 #define R2_STACK_OFFSET 40
185 #define PPC_INST_LD_TOC (PPC_INST_LD | ___PPC_RT(__REG_R2) | \
186 ___PPC_RA(__REG_R1) | R2_STACK_OFFSET)
188 /* usually preceded by a mflr r0 */
189 #define PPC_INST_STD_LR (PPC_INST_STD | ___PPC_RS(__REG_R0) | \
190 ___PPC_RA(__REG_R1) | PPC_LR_STKOFF)
191 #endif /* CONFIG_PPC64 */
193 #endif /* _ASM_POWERPC_CODE_PATCHING_H */