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
|
// SPDX-License-Identifier: GPL-2.0
#include <linux/spinlock.h>
#include <linux/hardirq.h>
#include <linux/ftrace.h>
#include <linux/percpu.h>
#include <linux/init.h>
#include <linux/list.h>
#include <trace/syscall.h>
#include <asm/ftrace.h>
#ifdef CONFIG_DYNAMIC_FTRACE
static const u32 ftrace_nop = 0x01000000;
static u32 ftrace_call_replace(unsigned long ip, unsigned long addr)
{
u32 call;
s32 off;
off = ((s32)addr - (s32)ip);
call = 0x40000000 | ((u32)off >> 2);
return call;
}
static int ftrace_modify_code(unsigned long ip, u32 old, u32 new)
{
u32 replaced;
int faulted;
__asm__ __volatile__(
"1: cas [%[ip]], %[old], %[new]\n"
" flush %[ip]\n"
" mov 0, %[faulted]\n"
"2:\n"
" .section .fixup,#alloc,#execinstr\n"
" .align 4\n"
"3: sethi %%hi(2b), %[faulted]\n"
" jmpl %[faulted] + %%lo(2b), %%g0\n"
" mov 1, %[faulted]\n"
" .previous\n"
" .section __ex_table,\"a\"\n"
" .align 4\n"
" .word 1b, 3b\n"
" .previous\n"
: "=r" (replaced), [faulted] "=r" (faulted)
: [new] "0" (new), [old] "r" (old), [ip] "r" (ip)
: "memory");
if (replaced != old && replaced != new)
faulted = 2;
return faulted;
}
int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr)
{
unsigned long ip = rec->ip;
u32 old, new;
old = ftrace_call_replace(ip, addr);
new = ftrace_nop;
return ftrace_modify_code(ip, old, new);
}
int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
{
unsigned long ip = rec->ip;
u32 old, new;
old = ftrace_nop;
new = ftrace_call_replace(ip, addr);
return ftrace_modify_code(ip, old, new);
}
int ftrace_update_ftrace_func(ftrace_func_t func)
{
unsigned long ip = (unsigned long)(&ftrace_call);
u32 old, new;
old = *(u32 *) &ftrace_call;
new = ftrace_call_replace(ip, (unsigned long)func);
return ftrace_modify_code(ip, old, new);
}
int __init ftrace_dyn_arch_init(void)
{
return 0;
}
#endif
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
#ifdef CONFIG_DYNAMIC_FTRACE
extern void ftrace_graph_call(void);
int ftrace_enable_ftrace_graph_caller(void)
{
unsigned long ip = (unsigned long)(&ftrace_graph_call);
u32 old, new;
old = *(u32 *) &ftrace_graph_call;
new = ftrace_call_replace(ip, (unsigned long) &ftrace_graph_caller);
return ftrace_modify_code(ip, old, new);
}
int ftrace_disable_ftrace_graph_caller(void)
{
unsigned long ip = (unsigned long)(&ftrace_graph_call);
u32 old, new;
old = *(u32 *) &ftrace_graph_call;
new = ftrace_call_replace(ip, (unsigned long) &ftrace_stub);
return ftrace_modify_code(ip, old, new);
}
#endif /* !CONFIG_DYNAMIC_FTRACE */
/*
* Hook the return address and push it in the stack of return addrs
* in current thread info.
*/
unsigned long prepare_ftrace_return(unsigned long parent,
unsigned long self_addr,
unsigned long frame_pointer)
{
unsigned long return_hooker = (unsigned long) &return_to_handler;
struct ftrace_graph_ent trace;
if (unlikely(atomic_read(¤t->tracing_graph_pause)))
return parent + 8UL;
trace.func = self_addr;
trace.depth = current->curr_ret_stack + 1;
/* Only trace if the calling function expects to */
if (!ftrace_graph_entry(&trace))
return parent + 8UL;
if (ftrace_push_return_trace(parent, self_addr, &trace.depth,
frame_pointer, NULL) == -EBUSY)
return parent + 8UL;
return return_hooker;
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
|
