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
|
/*
* Copyright (C) 2000 Anton Blanchard (anton@linuxcare.com)
*
* This file implements mcount(), which is used to collect profiling data.
* This can also be tweaked for kernel stack overflow detection.
*/
#include <linux/linkage.h>
#include <asm/ptrace.h>
#include <asm/thread_info.h>
/*
* This is the main variant and is called by C code. GCC's -pg option
* automatically instruments every C function with a call to this.
*/
#ifdef CONFIG_STACK_DEBUG
#define OVSTACKSIZE 4096 /* lets hope this is enough */
.data
.align 8
panicstring:
.asciz "Stack overflow\n"
.align 8
ovstack:
.skip OVSTACKSIZE
#endif
.text
.align 32
.globl _mcount
.type _mcount,#function
.globl mcount
.type mcount,#function
_mcount:
mcount:
#ifdef CONFIG_STACK_DEBUG
/*
* Check whether %sp is dangerously low.
*/
ldub [%g6 + TI_FPDEPTH], %g1
srl %g1, 1, %g3
add %g3, 1, %g3
sllx %g3, 8, %g3 ! each fpregs frame is 256b
add %g3, 192, %g3
add %g6, %g3, %g3 ! where does task_struct+frame end?
sub %g3, STACK_BIAS, %g3
cmp %sp, %g3
bg,pt %xcc, 1f
nop
lduh [%g6 + TI_CPU], %g1
sethi %hi(hardirq_stack), %g3
or %g3, %lo(hardirq_stack), %g3
sllx %g1, 3, %g1
ldx [%g3 + %g1], %g7
sub %g7, STACK_BIAS, %g7
cmp %sp, %g7
bleu,pt %xcc, 2f
sethi %hi(THREAD_SIZE), %g3
add %g7, %g3, %g7
cmp %sp, %g7
blu,pn %xcc, 1f
2: sethi %hi(softirq_stack), %g3
or %g3, %lo(softirq_stack), %g3
ldx [%g3 + %g1], %g7
sub %g7, STACK_BIAS, %g7
cmp %sp, %g7
bleu,pt %xcc, 3f
sethi %hi(THREAD_SIZE), %g3
add %g7, %g3, %g7
cmp %sp, %g7
blu,pn %xcc, 1f
nop
/* If we are already on ovstack, don't hop onto it
* again, we are already trying to output the stack overflow
* message.
*/
3: sethi %hi(ovstack), %g7 ! cant move to panic stack fast enough
or %g7, %lo(ovstack), %g7
add %g7, OVSTACKSIZE, %g3
sub %g3, STACK_BIAS + 192, %g3
sub %g7, STACK_BIAS, %g7
cmp %sp, %g7
blu,pn %xcc, 2f
cmp %sp, %g3
bleu,pn %xcc, 1f
nop
2: mov %g3, %sp
sethi %hi(panicstring), %g3
call prom_printf
or %g3, %lo(panicstring), %o0
call prom_halt
nop
1:
#endif
#ifdef CONFIG_FUNCTION_TRACER
#ifdef CONFIG_DYNAMIC_FTRACE
/* Do nothing, the retl/nop below is all we need. */
#else
sethi %hi(function_trace_stop), %g1
lduw [%g1 + %lo(function_trace_stop)], %g2
brnz,pn %g2, 1f
sethi %hi(ftrace_trace_function), %g1
sethi %hi(ftrace_stub), %g2
ldx [%g1 + %lo(ftrace_trace_function)], %g1
or %g2, %lo(ftrace_stub), %g2
cmp %g1, %g2
be,pn %icc, 1f
mov %i7, %o1
jmpl %g1, %g0
mov %o7, %o0
/* not reached */
1:
#endif
#endif
retl
nop
.size _mcount,.-_mcount
.size mcount,.-mcount
#ifdef CONFIG_FUNCTION_TRACER
.globl ftrace_stub
.type ftrace_stub,#function
ftrace_stub:
retl
nop
.size ftrace_stub,.-ftrace_stub
#ifdef CONFIG_DYNAMIC_FTRACE
.globl ftrace_caller
.type ftrace_caller,#function
ftrace_caller:
sethi %hi(function_trace_stop), %g1
mov %i7, %o1
lduw [%g1 + %lo(function_trace_stop)], %g2
brnz,pn %g2, ftrace_stub
mov %o7, %o0
.globl ftrace_call
ftrace_call:
/* If the final kernel link ever turns on relaxation, we'll need
* to do something about this tail call. Otherwise the linker
* will rewrite the call into a branch and nop out the move
* instruction.
*/
call ftrace_stub
mov %o0, %o7
retl
nop
.size ftrace_call,.-ftrace_call
.size ftrace_caller,.-ftrace_caller
#endif
#endif
|