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
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
|
// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
#include <linux/ftrace.h>
#include <linux/uaccess.h>
#include <linux/stop_machine.h>
#include <asm/cacheflush.h>
#ifdef CONFIG_DYNAMIC_FTRACE
#define NOP 0x4000
#define NOP32_HI 0xc400
#define NOP32_LO 0x4820
#define PUSH_LR 0x14d0
#define MOVIH_LINK 0xea3a
#define ORI_LINK 0xef5a
#define JSR_LINK 0xe8fa
#define BSR_LINK 0xe000
/*
* Gcc-csky with -pg will insert stub in function prologue:
* push lr
* jbsr _mcount
* nop32
* nop32
*
* If the (callee - current_pc) is less then 64MB, we'll use bsr:
* push lr
* bsr _mcount
* nop32
* nop32
* else we'll use (movih + ori + jsr):
* push lr
* movih r26, ...
* ori r26, ...
* jsr r26
*
* (r26 is our reserved link-reg)
*
*/
static inline void make_jbsr(unsigned long callee, unsigned long pc,
uint16_t *call, bool nolr)
{
long offset;
call[0] = nolr ? NOP : PUSH_LR;
offset = (long) callee - (long) pc;
if (unlikely(offset < -67108864 || offset > 67108864)) {
call[1] = MOVIH_LINK;
call[2] = callee >> 16;
call[3] = ORI_LINK;
call[4] = callee & 0xffff;
call[5] = JSR_LINK;
call[6] = 0;
} else {
offset = offset >> 1;
call[1] = BSR_LINK |
((uint16_t)((unsigned long) offset >> 16) & 0x3ff);
call[2] = (uint16_t)((unsigned long) offset & 0xffff);
call[3] = call[5] = NOP32_HI;
call[4] = call[6] = NOP32_LO;
}
}
static uint16_t nops[7] = {NOP, NOP32_HI, NOP32_LO, NOP32_HI, NOP32_LO,
NOP32_HI, NOP32_LO};
static int ftrace_check_current_nop(unsigned long hook)
{
uint16_t olds[7];
unsigned long hook_pos = hook - 2;
if (probe_kernel_read((void *)olds, (void *)hook_pos, sizeof(nops)))
return -EFAULT;
if (memcmp((void *)nops, (void *)olds, sizeof(nops))) {
pr_err("%p: nop but get (%04x %04x %04x %04x %04x %04x %04x)\n",
(void *)hook_pos,
olds[0], olds[1], olds[2], olds[3], olds[4], olds[5],
olds[6]);
return -EINVAL;
}
return 0;
}
static int ftrace_modify_code(unsigned long hook, unsigned long target,
bool enable, bool nolr)
{
uint16_t call[7];
unsigned long hook_pos = hook - 2;
int ret = 0;
make_jbsr(target, hook, call, nolr);
ret = probe_kernel_write((void *)hook_pos, enable ? call : nops,
sizeof(nops));
if (ret)
return -EPERM;
flush_icache_range(hook_pos, hook_pos + MCOUNT_INSN_SIZE);
return 0;
}
int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
{
int ret = ftrace_check_current_nop(rec->ip);
if (ret)
return ret;
return ftrace_modify_code(rec->ip, addr, true, false);
}
int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
unsigned long addr)
{
return ftrace_modify_code(rec->ip, addr, false, false);
}
int ftrace_update_ftrace_func(ftrace_func_t func)
{
int ret = ftrace_modify_code((unsigned long)&ftrace_call,
(unsigned long)func, true, true);
if (!ret)
ret = ftrace_modify_code((unsigned long)&ftrace_regs_call,
(unsigned long)func, true, true);
return ret;
}
int __init ftrace_dyn_arch_init(void)
{
return 0;
}
#endif /* CONFIG_DYNAMIC_FTRACE */
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
unsigned long addr)
{
return ftrace_modify_code(rec->ip, addr, true, true);
}
#endif
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
unsigned long frame_pointer)
{
unsigned long return_hooker = (unsigned long)&return_to_handler;
unsigned long old;
if (unlikely(atomic_read(¤t->tracing_graph_pause)))
return;
old = *parent;
if (!function_graph_enter(old, self_addr,
*(unsigned long *)frame_pointer, parent)) {
/*
* For csky-gcc function has sub-call:
* subi sp, sp, 8
* stw r8, (sp, 0)
* mov r8, sp
* st.w r15, (sp, 0x4)
* push r15
* jl _mcount
* We only need set *parent for resume
*
* For csky-gcc function has no sub-call:
* subi sp, sp, 4
* stw r8, (sp, 0)
* mov r8, sp
* push r15
* jl _mcount
* We need set *parent and *(frame_pointer + 4) for resume,
* because lr is resumed twice.
*/
*parent = return_hooker;
frame_pointer += 4;
if (*(unsigned long *)frame_pointer == old)
*(unsigned long *)frame_pointer = return_hooker;
}
}
#ifdef CONFIG_DYNAMIC_FTRACE
int ftrace_enable_ftrace_graph_caller(void)
{
return ftrace_modify_code((unsigned long)&ftrace_graph_call,
(unsigned long)&ftrace_graph_caller, true, true);
}
int ftrace_disable_ftrace_graph_caller(void)
{
return ftrace_modify_code((unsigned long)&ftrace_graph_call,
(unsigned long)&ftrace_graph_caller, false, true);
}
#endif /* CONFIG_DYNAMIC_FTRACE */
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
#ifndef CONFIG_CPU_HAS_ICACHE_INS
struct ftrace_modify_param {
int command;
atomic_t cpu_count;
};
static int __ftrace_modify_code(void *data)
{
struct ftrace_modify_param *param = data;
if (atomic_inc_return(¶m->cpu_count) == 1) {
ftrace_modify_all_code(param->command);
atomic_inc(¶m->cpu_count);
} else {
while (atomic_read(¶m->cpu_count) <= num_online_cpus())
cpu_relax();
local_icache_inv_all(NULL);
}
return 0;
}
void arch_ftrace_update_code(int command)
{
struct ftrace_modify_param param = { command, ATOMIC_INIT(0) };
stop_machine(__ftrace_modify_code, ¶m, cpu_online_mask);
}
#endif
/* _mcount is defined in abi's mcount.S */
EXPORT_SYMBOL(_mcount);
|
