1/* SPDX-License-Identifier: GPL-2.0 */
2/* Copyright (C) 2017 Andes Technology Corporation */
3
4#include <linux/init.h>
5#include <linux/linkage.h>
6#include <linux/export.h>
7#include <asm/asm.h>
8#include <asm/csr.h>
9#include <asm/unistd.h>
10#include <asm/thread_info.h>
11#include <asm/asm-offsets.h>
12#include <asm/ftrace.h>
13
14 .text
15
16#define FENTRY_RA_OFFSET 8
17#define ABI_SIZE_ON_STACK 80
18#define ABI_A0 0
19#define ABI_A1 8
20#define ABI_A2 16
21#define ABI_A3 24
22#define ABI_A4 32
23#define ABI_A5 40
24#define ABI_A6 48
25#define ABI_A7 56
26#define ABI_T0 64
27#define ABI_RA 72
28
29 .macro SAVE_ABI
30 addi sp, sp, -ABI_SIZE_ON_STACK
31
32 REG_S a0, ABI_A0(sp)
33 REG_S a1, ABI_A1(sp)
34 REG_S a2, ABI_A2(sp)
35 REG_S a3, ABI_A3(sp)
36 REG_S a4, ABI_A4(sp)
37 REG_S a5, ABI_A5(sp)
38 REG_S a6, ABI_A6(sp)
39 REG_S a7, ABI_A7(sp)
40 REG_S t0, ABI_T0(sp)
41 REG_S ra, ABI_RA(sp)
42 .endm
43
44 .macro RESTORE_ABI
45 REG_L a0, ABI_A0(sp)
46 REG_L a1, ABI_A1(sp)
47 REG_L a2, ABI_A2(sp)
48 REG_L a3, ABI_A3(sp)
49 REG_L a4, ABI_A4(sp)
50 REG_L a5, ABI_A5(sp)
51 REG_L a6, ABI_A6(sp)
52 REG_L a7, ABI_A7(sp)
53 REG_L t0, ABI_T0(sp)
54 REG_L ra, ABI_RA(sp)
55
56 addi sp, sp, ABI_SIZE_ON_STACK
57 .endm
58
59#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
60
61/**
62* SAVE_ABI_REGS - save regs against the pt_regs struct
63*
64* @all: tell if saving all the regs
65*
66* If all is set, all the regs will be saved, otherwise only ABI
67* related regs (a0-a7,epc,ra and optional s0) will be saved.
68*
69* After the stack is established,
70*
71* 0(sp) stores the PC of the traced function which can be accessed
72* by &(fregs)->regs->epc in tracing function. Note that the real
73* function entry address should be computed with -FENTRY_RA_OFFSET.
74*
75* 8(sp) stores the function return address (i.e. parent IP) that
76* can be accessed by &(fregs)->regs->ra in tracing function.
77*
78* The other regs are saved at the respective localtion and accessed
79* by the respective pt_regs member.
80*
81* Here is the layout of stack for your reference.
82*
83* PT_SIZE_ON_STACK -> +++++++++
84* + ..... +
85* + t3-t6 +
86* + s2-s11+
87* + a0-a7 + --++++-> ftrace_caller saved
88* + s1 + +
89* + s0 + --+
90* + t0-t2 + +
91* + tp + +
92* + gp + +
93* + sp + +
94* + ra + --+ // parent IP
95* sp -> + epc + --+ // PC
96* +++++++++
97**/
98 .macro SAVE_ABI_REGS, all=0
99 addi sp, sp, -PT_SIZE_ON_STACK
100
101 REG_S t0, PT_EPC(sp)
102 REG_S x1, PT_RA(sp)
103
104 // save the ABI regs
105
106 REG_S x10, PT_A0(sp)
107 REG_S x11, PT_A1(sp)
108 REG_S x12, PT_A2(sp)
109 REG_S x13, PT_A3(sp)
110 REG_S x14, PT_A4(sp)
111 REG_S x15, PT_A5(sp)
112 REG_S x16, PT_A6(sp)
113 REG_S x17, PT_A7(sp)
114
115 // save the leftover regs
116
117 .if \all == 1
118 REG_S x2, PT_SP(sp)
119 REG_S x3, PT_GP(sp)
120 REG_S x4, PT_TP(sp)
121 REG_S x5, PT_T0(sp)
122 REG_S x6, PT_T1(sp)
123 REG_S x7, PT_T2(sp)
124 REG_S x8, PT_S0(sp)
125 REG_S x9, PT_S1(sp)
126 REG_S x18, PT_S2(sp)
127 REG_S x19, PT_S3(sp)
128 REG_S x20, PT_S4(sp)
129 REG_S x21, PT_S5(sp)
130 REG_S x22, PT_S6(sp)
131 REG_S x23, PT_S7(sp)
132 REG_S x24, PT_S8(sp)
133 REG_S x25, PT_S9(sp)
134 REG_S x26, PT_S10(sp)
135 REG_S x27, PT_S11(sp)
136 REG_S x28, PT_T3(sp)
137 REG_S x29, PT_T4(sp)
138 REG_S x30, PT_T5(sp)
139 REG_S x31, PT_T6(sp)
140
141 // save s0 if FP_TEST defined
142
143 .else
144#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
145 REG_S x8, PT_S0(sp)
146#endif
147 .endif
148 .endm
149
150 .macro RESTORE_ABI_REGS, all=0
151 REG_L t0, PT_EPC(sp)
152 REG_L x1, PT_RA(sp)
153 REG_L x10, PT_A0(sp)
154 REG_L x11, PT_A1(sp)
155 REG_L x12, PT_A2(sp)
156 REG_L x13, PT_A3(sp)
157 REG_L x14, PT_A4(sp)
158 REG_L x15, PT_A5(sp)
159 REG_L x16, PT_A6(sp)
160 REG_L x17, PT_A7(sp)
161
162 .if \all == 1
163 REG_L x2, PT_SP(sp)
164 REG_L x3, PT_GP(sp)
165 REG_L x4, PT_TP(sp)
166 REG_L x6, PT_T1(sp)
167 REG_L x7, PT_T2(sp)
168 REG_L x8, PT_S0(sp)
169 REG_L x9, PT_S1(sp)
170 REG_L x18, PT_S2(sp)
171 REG_L x19, PT_S3(sp)
172 REG_L x20, PT_S4(sp)
173 REG_L x21, PT_S5(sp)
174 REG_L x22, PT_S6(sp)
175 REG_L x23, PT_S7(sp)
176 REG_L x24, PT_S8(sp)
177 REG_L x25, PT_S9(sp)
178 REG_L x26, PT_S10(sp)
179 REG_L x27, PT_S11(sp)
180 REG_L x28, PT_T3(sp)
181 REG_L x29, PT_T4(sp)
182 REG_L x30, PT_T5(sp)
183 REG_L x31, PT_T6(sp)
184
185 .else
186#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
187 REG_L x8, PT_S0(sp)
188#endif
189 .endif
190 addi sp, sp, PT_SIZE_ON_STACK
191 .endm
192
193 .macro PREPARE_ARGS
194 addi a0, t0, -FENTRY_RA_OFFSET
195 la a1, function_trace_op
196 REG_L a2, 0(a1)
197 mv a1, ra
198 mv a3, sp
199 .endm
200
201#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
202
203#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
204SYM_FUNC_START(ftrace_caller)
205 SAVE_ABI
206
207 addi a0, t0, -FENTRY_RA_OFFSET
208 la a1, function_trace_op
209 REG_L a2, 0(a1)
210 mv a1, ra
211 mv a3, sp
212
213SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL)
214 call ftrace_stub
215
216#ifdef CONFIG_FUNCTION_GRAPH_TRACER
217 addi a0, sp, ABI_RA
218 REG_L a1, ABI_T0(sp)
219 addi a1, a1, -FENTRY_RA_OFFSET
220#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
221 mv a2, s0
222#endif
223SYM_INNER_LABEL(ftrace_graph_call, SYM_L_GLOBAL)
224 call ftrace_stub
225#endif
226 RESTORE_ABI
227 jr t0
228SYM_FUNC_END(ftrace_caller)
229
230#else /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
231SYM_FUNC_START(ftrace_regs_caller)
232 mv t1, zero
233 SAVE_ABI_REGS 1
234 PREPARE_ARGS
235
236SYM_INNER_LABEL(ftrace_regs_call, SYM_L_GLOBAL)
237 call ftrace_stub
238
239 RESTORE_ABI_REGS 1
240 bnez t1, .Ldirect
241 jr t0
242.Ldirect:
243 jr t1
244SYM_FUNC_END(ftrace_regs_caller)
245
246SYM_FUNC_START(ftrace_caller)
247 SAVE_ABI_REGS 0
248 PREPARE_ARGS
249
250SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL)
251 call ftrace_stub
252
253 RESTORE_ABI_REGS 0
254 jr t0
255SYM_FUNC_END(ftrace_caller)
256#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
257
258#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
259SYM_CODE_START(ftrace_stub_direct_tramp)
260 jr t0
261SYM_CODE_END(ftrace_stub_direct_tramp)
262#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
263

source code of linux/arch/riscv/kernel/mcount-dyn.S