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
|
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2022 Loongson Technology Corporation Limited
*/
#include <asm/ftrace.h>
#include <asm/regdef.h>
#include <asm/stackframe.h>
.text
/*
* Due to -fpatchable-function-entry=2: the compiler inserted 2 NOPs before the
* regular C function prologue. When PC arrived here, the last 2 instructions
* are as follows:
* move t0, ra
* bl callsite (for modules, callsite is a tramplione)
*
* modules trampoline is as follows:
* lu12i.w t1, callsite[31:12]
* lu32i.d t1, callsite[51:32]
* lu52i.d t1, t1, callsite[63:52]
* jirl zero, t1, callsite[11:0] >> 2
*
* See arch/loongarch/kernel/ftrace_dyn.c for details. Here, pay attention to
* that the T series regs are available and safe because each C functions
* follows the LoongArch's psABI as well.
*/
.macro ftrace_regs_entry allregs=0
PTR_ADDI sp, sp, -PT_SIZE
PTR_S t0, sp, PT_R1 /* Save parent ra at PT_R1(RA) */
PTR_S a0, sp, PT_R4
PTR_S a1, sp, PT_R5
PTR_S a2, sp, PT_R6
PTR_S a3, sp, PT_R7
PTR_S a4, sp, PT_R8
PTR_S a5, sp, PT_R9
PTR_S a6, sp, PT_R10
PTR_S a7, sp, PT_R11
PTR_S fp, sp, PT_R22
.if \allregs
PTR_S tp, sp, PT_R2
PTR_S t0, sp, PT_R12
PTR_S t2, sp, PT_R14
PTR_S t3, sp, PT_R15
PTR_S t4, sp, PT_R16
PTR_S t5, sp, PT_R17
PTR_S t6, sp, PT_R18
PTR_S t7, sp, PT_R19
PTR_S t8, sp, PT_R20
PTR_S u0, sp, PT_R21
PTR_S s0, sp, PT_R23
PTR_S s1, sp, PT_R24
PTR_S s2, sp, PT_R25
PTR_S s3, sp, PT_R26
PTR_S s4, sp, PT_R27
PTR_S s5, sp, PT_R28
PTR_S s6, sp, PT_R29
PTR_S s7, sp, PT_R30
PTR_S s8, sp, PT_R31
/* Clear it for later use as a flag sometimes. */
PTR_S zero, sp, PT_R0
.endif
PTR_S ra, sp, PT_ERA /* Save trace function ra at PT_ERA */
move t1, zero
PTR_S t1, sp, PT_R13
PTR_ADDI t8, sp, PT_SIZE
PTR_S t8, sp, PT_R3
.endm
SYM_FUNC_START(ftrace_stub)
jr ra
SYM_FUNC_END(ftrace_stub)
SYM_CODE_START(ftrace_common)
PTR_ADDI a0, ra, -8 /* arg0: ip */
move a1, t0 /* arg1: parent_ip */
la.pcrel t1, function_trace_op
PTR_L a2, t1, 0 /* arg2: op */
move a3, sp /* arg3: regs */
SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL)
bl ftrace_stub
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
SYM_INNER_LABEL(ftrace_graph_call, SYM_L_GLOBAL)
nop /* b ftrace_graph_caller */
#endif
/*
* As we didn't use S series regs in this assmembly code and all calls
* are C function which will save S series regs by themselves, there is
* no need to restore S series regs. The T series is available and safe
* at the callsite, so there is no need to restore the T series regs.
*/
ftrace_common_return:
PTR_L ra, sp, PT_R1
PTR_L a0, sp, PT_R4
PTR_L a1, sp, PT_R5
PTR_L a2, sp, PT_R6
PTR_L a3, sp, PT_R7
PTR_L a4, sp, PT_R8
PTR_L a5, sp, PT_R9
PTR_L a6, sp, PT_R10
PTR_L a7, sp, PT_R11
PTR_L fp, sp, PT_R22
PTR_L t0, sp, PT_ERA
PTR_L t1, sp, PT_R13
PTR_ADDI sp, sp, PT_SIZE
bnez t1, .Ldirect
jr t0
.Ldirect:
jr t1
SYM_CODE_END(ftrace_common)
SYM_CODE_START(ftrace_caller)
ftrace_regs_entry allregs=0
b ftrace_common
SYM_CODE_END(ftrace_caller)
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
SYM_CODE_START(ftrace_regs_caller)
ftrace_regs_entry allregs=1
b ftrace_common
SYM_CODE_END(ftrace_regs_caller)
#endif
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
SYM_CODE_START(ftrace_graph_caller)
PTR_L a0, sp, PT_ERA
PTR_ADDI a0, a0, -8 /* arg0: self_addr */
PTR_ADDI a1, sp, PT_R1 /* arg1: parent */
bl prepare_ftrace_return
b ftrace_common_return
SYM_CODE_END(ftrace_graph_caller)
SYM_CODE_START(return_to_handler)
/* Save return value regs */
PTR_ADDI sp, sp, -FGRET_REGS_SIZE
PTR_S a0, sp, FGRET_REGS_A0
PTR_S a1, sp, FGRET_REGS_A1
PTR_S zero, sp, FGRET_REGS_FP
move a0, sp
bl ftrace_return_to_handler
move ra, a0
/* Restore return value regs */
PTR_L a0, sp, FGRET_REGS_A0
PTR_L a1, sp, FGRET_REGS_A1
PTR_ADDI sp, sp, FGRET_REGS_SIZE
jr ra
SYM_CODE_END(return_to_handler)
#endif
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
SYM_CODE_START(ftrace_stub_direct_tramp)
jr t0
SYM_CODE_END(ftrace_stub_direct_tramp)
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
|
