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);
ftrace_call_adjust(unsigned long addr)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
arch_trace_is_compat_syscall(struct pt_regs * regs)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
arch_syscall_match_sym_name(const char * sym,const char * 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 #define HAVE_ARCH_FTRACE_REGS
129 struct ftrace_ops;
130 struct ftrace_regs;
131 #define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
132
133 struct __arch_ftrace_regs {
134 unsigned long epc;
135 unsigned long ra;
136 unsigned long sp;
137 unsigned long s0;
138 unsigned long t1;
139 union {
140 unsigned long args[8];
141 struct {
142 unsigned long a0;
143 unsigned long a1;
144 unsigned long a2;
145 unsigned long a3;
146 unsigned long a4;
147 unsigned long a5;
148 unsigned long a6;
149 unsigned long a7;
150 };
151 };
152 };
153
ftrace_regs_get_instruction_pointer(const struct ftrace_regs * fregs)154 static __always_inline unsigned long ftrace_regs_get_instruction_pointer(const struct ftrace_regs
155 *fregs)
156 {
157 return arch_ftrace_regs(fregs)->epc;
158 }
159
ftrace_regs_set_instruction_pointer(struct ftrace_regs * fregs,unsigned long pc)160 static __always_inline void ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs,
161 unsigned long pc)
162 {
163 arch_ftrace_regs(fregs)->epc = pc;
164 }
165
ftrace_regs_get_stack_pointer(const struct ftrace_regs * fregs)166 static __always_inline unsigned long ftrace_regs_get_stack_pointer(const struct ftrace_regs *fregs)
167 {
168 return arch_ftrace_regs(fregs)->sp;
169 }
170
ftrace_regs_get_frame_pointer(const struct ftrace_regs * fregs)171 static __always_inline unsigned long ftrace_regs_get_frame_pointer(const struct ftrace_regs *fregs)
172 {
173 return arch_ftrace_regs(fregs)->s0;
174 }
175
ftrace_regs_get_argument(struct ftrace_regs * fregs,unsigned int n)176 static __always_inline unsigned long ftrace_regs_get_argument(struct ftrace_regs *fregs,
177 unsigned int n)
178 {
179 if (n < 8)
180 return arch_ftrace_regs(fregs)->args[n];
181 return 0;
182 }
183
ftrace_regs_get_return_value(const struct ftrace_regs * fregs)184 static __always_inline unsigned long ftrace_regs_get_return_value(const struct ftrace_regs *fregs)
185 {
186 return arch_ftrace_regs(fregs)->a0;
187 }
188
ftrace_regs_get_return_address(const struct ftrace_regs * fregs)189 static __always_inline unsigned long ftrace_regs_get_return_address(const struct ftrace_regs *fregs)
190 {
191 return arch_ftrace_regs(fregs)->ra;
192 }
193
ftrace_regs_set_return_value(struct ftrace_regs * fregs,unsigned long ret)194 static __always_inline void ftrace_regs_set_return_value(struct ftrace_regs *fregs,
195 unsigned long ret)
196 {
197 arch_ftrace_regs(fregs)->a0 = ret;
198 }
199
ftrace_override_function_with_return(struct ftrace_regs * fregs)200 static __always_inline void ftrace_override_function_with_return(struct ftrace_regs *fregs)
201 {
202 arch_ftrace_regs(fregs)->epc = arch_ftrace_regs(fregs)->ra;
203 }
204
205 static __always_inline struct pt_regs *
ftrace_partial_regs(const struct ftrace_regs * fregs,struct pt_regs * regs)206 ftrace_partial_regs(const struct ftrace_regs *fregs, struct pt_regs *regs)
207 {
208 struct __arch_ftrace_regs *afregs = arch_ftrace_regs(fregs);
209
210 memcpy(®s->a0, afregs->args, sizeof(afregs->args));
211 regs->epc = afregs->epc;
212 regs->ra = afregs->ra;
213 regs->sp = afregs->sp;
214 regs->s0 = afregs->s0;
215 regs->t1 = afregs->t1;
216 return regs;
217 }
218
219 int ftrace_regs_query_register_offset(const char *name);
220
221 void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
222 struct ftrace_ops *op, struct ftrace_regs *fregs);
223 #define ftrace_graph_func ftrace_graph_func
224
arch_ftrace_set_direct_caller(struct ftrace_regs * fregs,unsigned long addr)225 static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs, unsigned long addr)
226 {
227 arch_ftrace_regs(fregs)->t1 = addr;
228 }
229 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_ARGS */
230
231 #endif /* __ASSEMBLY__ */
232
233 #endif /* CONFIG_DYNAMIC_FTRACE */
234
235 #endif /* _ASM_RISCV_FTRACE_H */
236