1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
|
#ifndef _ASM_POWERPC_CODE_PATCHING_H
#define _ASM_POWERPC_CODE_PATCHING_H
/*
* Copyright 2008, Michael Ellerman, IBM Corporation.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <asm/types.h>
#include <asm/ppc-opcode.h>
#include <linux/string.h>
#include <linux/kallsyms.h>
#include <asm/asm-compat.h>
/* Flags for create_branch:
* "b" == create_branch(addr, target, 0);
* "ba" == create_branch(addr, target, BRANCH_ABSOLUTE);
* "bl" == create_branch(addr, target, BRANCH_SET_LINK);
* "bla" == create_branch(addr, target, BRANCH_ABSOLUTE | BRANCH_SET_LINK);
*/
#define BRANCH_SET_LINK 0x1
#define BRANCH_ABSOLUTE 0x2
bool is_offset_in_branch_range(long offset);
bool is_offset_in_cond_branch_range(long offset);
unsigned int create_branch(const unsigned int *addr,
unsigned long target, int flags);
unsigned int create_cond_branch(const unsigned int *addr,
unsigned long target, int flags);
int patch_branch(unsigned int *addr, unsigned long target, int flags);
int patch_instruction(unsigned int *addr, unsigned int instr);
int raw_patch_instruction(unsigned int *addr, unsigned int instr);
int patch_instruction_site(s32 *addr, unsigned int instr);
int patch_branch_site(s32 *site, unsigned long target, int flags);
int instr_is_relative_branch(unsigned int instr);
int instr_is_relative_link_branch(unsigned int instr);
int instr_is_branch_to_addr(const unsigned int *instr, unsigned long addr);
unsigned long branch_target(const unsigned int *instr);
unsigned int translate_branch(const unsigned int *dest,
const unsigned int *src);
extern bool is_conditional_branch(unsigned int instr);
#ifdef CONFIG_PPC_BOOK3E_64
void __patch_exception(int exc, unsigned long addr);
#define patch_exception(exc, name) do { \
extern unsigned int name; \
__patch_exception((exc), (unsigned long)&name); \
} while (0)
#endif
#define OP_RT_RA_MASK 0xffff0000UL
#define LIS_R2 0x3c400000UL
#define ADDIS_R2_R12 0x3c4c0000UL
#define ADDI_R2_R2 0x38420000UL
static inline unsigned long ppc_function_entry(void *func)
{
#ifdef PPC64_ELF_ABI_v2
u32 *insn = func;
/*
* A PPC64 ABIv2 function may have a local and a global entry
* point. We need to use the local entry point when patching
* functions, so identify and step over the global entry point
* sequence.
*
* The global entry point sequence is always of the form:
*
* addis r2,r12,XXXX
* addi r2,r2,XXXX
*
* A linker optimisation may convert the addis to lis:
*
* lis r2,XXXX
* addi r2,r2,XXXX
*/
if ((((*insn & OP_RT_RA_MASK) == ADDIS_R2_R12) ||
((*insn & OP_RT_RA_MASK) == LIS_R2)) &&
((*(insn+1) & OP_RT_RA_MASK) == ADDI_R2_R2))
return (unsigned long)(insn + 2);
else
return (unsigned long)func;
#elif defined(PPC64_ELF_ABI_v1)
/*
* On PPC64 ABIv1 the function pointer actually points to the
* function's descriptor. The first entry in the descriptor is the
* address of the function text.
*/
return ((func_descr_t *)func)->entry;
#else
return (unsigned long)func;
#endif
}
static inline unsigned long ppc_global_function_entry(void *func)
{
#ifdef PPC64_ELF_ABI_v2
/* PPC64 ABIv2 the global entry point is at the address */
return (unsigned long)func;
#else
/* All other cases there is no change vs ppc_function_entry() */
return ppc_function_entry(func);
#endif
}
/*
* Wrapper around kallsyms_lookup() to return function entry address:
* - For ABIv1, we lookup the dot variant.
* - For ABIv2, we return the local entry point.
*/
static inline unsigned long ppc_kallsyms_lookup_name(const char *name)
{
unsigned long addr;
#ifdef PPC64_ELF_ABI_v1
/* check for dot variant */
char dot_name[1 + KSYM_NAME_LEN];
bool dot_appended = false;
if (strnlen(name, KSYM_NAME_LEN) >= KSYM_NAME_LEN)
return 0;
if (name[0] != '.') {
dot_name[0] = '.';
dot_name[1] = '\0';
strlcat(dot_name, name, sizeof(dot_name));
dot_appended = true;
} else {
dot_name[0] = '\0';
strlcat(dot_name, name, sizeof(dot_name));
}
addr = kallsyms_lookup_name(dot_name);
if (!addr && dot_appended)
/* Let's try the original non-dot symbol lookup */
addr = kallsyms_lookup_name(name);
#elif defined(PPC64_ELF_ABI_v2)
addr = kallsyms_lookup_name(name);
if (addr)
addr = ppc_function_entry((void *)addr);
#else
addr = kallsyms_lookup_name(name);
#endif
return addr;
}
#ifdef CONFIG_PPC64
/*
* Some instruction encodings commonly used in dynamic ftracing
* and function live patching.
*/
/* This must match the definition of STK_GOT in <asm/ppc_asm.h> */
#ifdef PPC64_ELF_ABI_v2
#define R2_STACK_OFFSET 24
#else
#define R2_STACK_OFFSET 40
#endif
#define PPC_INST_LD_TOC (PPC_INST_LD | ___PPC_RT(__REG_R2) | \
___PPC_RA(__REG_R1) | R2_STACK_OFFSET)
/* usually preceded by a mflr r0 */
#define PPC_INST_STD_LR (PPC_INST_STD | ___PPC_RS(__REG_R0) | \
___PPC_RA(__REG_R1) | PPC_LR_STKOFF)
#endif /* CONFIG_PPC64 */
#endif /* _ASM_POWERPC_CODE_PATCHING_H */
|
