1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* Copyright (C) 2017 Andes Technology Corporation */
3
4 #ifndef _ASM_RISCV_FTRACE_H
5 #define _ASM_RISCV_FTRACE_H
6
7 /*
8 * The graph frame test is not possible if CONFIG_FRAME_POINTER is not enabled.
9 * Check arch/riscv/kernel/mcount.S for detail.
10 */
11 #if defined(CONFIG_FUNCTION_GRAPH_TRACER) && defined(CONFIG_FRAME_POINTER)
12 #define HAVE_FUNCTION_GRAPH_FP_TEST
13 #endif
14
15 #define ARCH_SUPPORTS_FTRACE_OPS 1
16 #ifndef __ASSEMBLY__
17
18 extern void *return_address(unsigned int level);
19
20 #define ftrace_return_address(n) return_address(n)
21
22 void _mcount(void);
23 static inline unsigned long ftrace_call_adjust(unsigned long addr)
24 {
25 return addr;
26 }
27
28 /*
29 * Let's do like x86/arm64 and ignore the compat syscalls.
30 */
31 #define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
32 static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs)
33 {
34 return is_compat_task();
35 }
36
37 #define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
38 static inline bool arch_syscall_match_sym_name(const char *sym,
39 const char *name)
40 {
41 /*
42 * Since all syscall functions have __riscv_ prefix, we must skip it.
43 * However, as we described above, we decided to ignore compat
44 * syscalls, so we don't care about __riscv_compat_ prefix here.
45 */
46 return !strcmp(sym + 8, name);
47 }
48
49 struct dyn_arch_ftrace {
50 };
51 #endif
52
53 #ifdef CONFIG_DYNAMIC_FTRACE
54 /*
55 * A general call in RISC-V is a pair of insts:
56 * 1) auipc: setting high-20 pc-related bits to ra register
57 * 2) jalr: setting low-12 offset to ra, jump to ra, and set ra to
58 * return address (original pc + 4)
59 *
60 *<ftrace enable>:
61 * 0: auipc t0/ra, 0x?
62 * 4: jalr t0/ra, ?(t0/ra)
63 *
64 *<ftrace disable>:
65 * 0: nop
66 * 4: nop
67 *
68 * Dynamic ftrace generates probes to call sites, so we must deal with
69 * both auipc and jalr at the same time.
70 */
71
72 #define MCOUNT_ADDR ((unsigned long)_mcount)
73 #define JALR_SIGN_MASK (0x00000800)
74 #define JALR_OFFSET_MASK (0x00000fff)
75 #define AUIPC_OFFSET_MASK (0xfffff000)
76 #define AUIPC_PAD (0x00001000)
77 #define JALR_SHIFT 20
78 #define JALR_RA (0x000080e7)
79 #define AUIPC_RA (0x00000097)
80 #define JALR_T0 (0x000282e7)
81 #define AUIPC_T0 (0x00000297)
82 #define NOP4 (0x00000013)
83
84 #define to_jalr_t0(offset) \
85 (((offset & JALR_OFFSET_MASK) << JALR_SHIFT) | JALR_T0)
86
87 #define to_auipc_t0(offset) \
88 ((offset & JALR_SIGN_MASK) ? \
89 (((offset & AUIPC_OFFSET_MASK) + AUIPC_PAD) | AUIPC_T0) : \
90 ((offset & AUIPC_OFFSET_MASK) | AUIPC_T0))
91
92 #define make_call_t0(caller, callee, call) \
93 do { \
94 unsigned int offset = \
95 (unsigned long) callee - (unsigned long) caller; \
96 call[0] = to_auipc_t0(offset); \
97 call[1] = to_jalr_t0(offset); \
98 } while (0)
99
100 #define to_jalr_ra(offset) \
101 (((offset & JALR_OFFSET_MASK) << JALR_SHIFT) | JALR_RA)
102
103 #define to_auipc_ra(offset) \
104 ((offset & JALR_SIGN_MASK) ? \
105 (((offset & AUIPC_OFFSET_MASK) + AUIPC_PAD) | AUIPC_RA) : \
106 ((offset & AUIPC_OFFSET_MASK) | AUIPC_RA))
107
108 #define make_call_ra(caller, callee, call) \
109 do { \
110 unsigned int offset = \
111 (unsigned long) callee - (unsigned long) caller; \
112 call[0] = to_auipc_ra(offset); \
113 call[1] = to_jalr_ra(offset); \
114 } while (0)
115
116 /*
117 * Let auipc+jalr be the basic *mcount unit*, so we make it 8 bytes here.
118 */
119 #define MCOUNT_INSN_SIZE 8
120
121 #ifndef __ASSEMBLY__
122 struct dyn_ftrace;
123 int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
124 #define ftrace_init_nop ftrace_init_nop
125
126 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
127 #define arch_ftrace_get_regs(regs) NULL
128 struct ftrace_ops;
129 struct ftrace_regs {
130 unsigned long epc;
131 unsigned long ra;
132 unsigned long sp;
133 unsigned long s0;
134 unsigned long t1;
135 union {
136 unsigned long args[8];
137 struct {
138 unsigned long a0;
139 unsigned long a1;
140 unsigned long a2;
141 unsigned long a3;
142 unsigned long a4;
143 unsigned long a5;
144 unsigned long a6;
145 unsigned long a7;
146 };
147 };
148 };
149
150 static __always_inline unsigned long ftrace_regs_get_instruction_pointer(const struct ftrace_regs
151 *fregs)
152 {
153 return fregs->epc;
154 }
155
156 static __always_inline void ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs,
157 unsigned long pc)
158 {
159 fregs->epc = pc;
160 }
161
162 static __always_inline unsigned long ftrace_regs_get_stack_pointer(const struct ftrace_regs *fregs)
163 {
164 return fregs->sp;
165 }
166
167 static __always_inline unsigned long ftrace_regs_get_argument(struct ftrace_regs *fregs,
168 unsigned int n)
169 {
170 if (n < 8)
171 return fregs->args[n];
172 return 0;
173 }
174
175 static __always_inline unsigned long ftrace_regs_get_return_value(const struct ftrace_regs *fregs)
176 {
177 return fregs->a0;
178 }
179
180 static __always_inline void ftrace_regs_set_return_value(struct ftrace_regs *fregs,
181 unsigned long ret)
182 {
183 fregs->a0 = ret;
184 }
185
186 static __always_inline void ftrace_override_function_with_return(struct ftrace_regs *fregs)
187 {
188 fregs->epc = fregs->ra;
189 }
190
191 int ftrace_regs_query_register_offset(const char *name);
192
193 void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
194 struct ftrace_ops *op, struct ftrace_regs *fregs);
195 #define ftrace_graph_func ftrace_graph_func
196
197 static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs, unsigned long addr)
198 {
199 fregs->t1 = addr;
200 }
201 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_ARGS */
202
203 #endif /* __ASSEMBLY__ */
204
205 #endif /* CONFIG_DYNAMIC_FTRACE */
206
207 #ifndef __ASSEMBLY__
208 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
209 struct fgraph_ret_regs {
210 unsigned long a1;
211 unsigned long a0;
212 unsigned long s0;
213 unsigned long ra;
214 };
215
216 static inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret_regs *ret_regs)
217 {
218 return ret_regs->a0;
219 }
220
221 static inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_ret_regs *ret_regs)
222 {
223 return ret_regs->s0;
224 }
225 #endif /* ifdef CONFIG_FUNCTION_GRAPH_TRACER */
226 #endif
227
228 #endif /* _ASM_RISCV_FTRACE_H */
229
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