1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * arch/arm64/include/asm/ftrace.h
4 *
5 * Copyright (C) 2013 Linaro Limited
6 * Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
7 */
8 #ifndef __ASM_FTRACE_H
9 #define __ASM_FTRACE_H
10
11 #include <asm/insn.h>
12
13 #define HAVE_FUNCTION_GRAPH_FP_TEST
14
15 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
16 #define ARCH_SUPPORTS_FTRACE_OPS 1
17 #else
18 #define MCOUNT_ADDR ((unsigned long)_mcount)
19 #endif
20
21 /* The BL at the callsite's adjusted rec->ip */
22 #define MCOUNT_INSN_SIZE AARCH64_INSN_SIZE
23
24 #define FTRACE_PLT_IDX 0
25 #define NR_FTRACE_PLTS 1
26
27 /*
28 * Currently, gcc tends to save the link register after the local variables
29 * on the stack. This causes the max stack tracer to report the function
30 * frame sizes for the wrong functions. By defining
31 * ARCH_FTRACE_SHIFT_STACK_TRACER, it will tell the stack tracer to expect
32 * to find the return address on the stack after the local variables have
33 * been set up.
34 *
35 * Note, this may change in the future, and we will need to deal with that
36 * if it were to happen.
37 */
38 #define ARCH_FTRACE_SHIFT_STACK_TRACER 1
39
40 #ifndef __ASSEMBLY__
41 #include <linux/compat.h>
42
43 extern void _mcount(unsigned long);
44 extern void *return_address(unsigned int);
45
46 struct dyn_arch_ftrace {
47 /* No extra data needed for arm64 */
48 };
49
50 extern unsigned long ftrace_graph_call;
51
52 extern void return_to_handler(void);
53
54 unsigned long ftrace_call_adjust(unsigned long addr);
55
56 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
57 struct dyn_ftrace;
58 struct ftrace_ops;
59
60 #define arch_ftrace_get_regs(regs) NULL
61
62 /*
63 * Note: sizeof(struct ftrace_regs) must be a multiple of 16 to ensure correct
64 * stack alignment
65 */
66 struct ftrace_regs {
67 /* x0 - x8 */
68 unsigned long regs[9];
69
70 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
71 unsigned long direct_tramp;
72 #else
73 unsigned long __unused;
74 #endif
75
76 unsigned long fp;
77 unsigned long lr;
78
79 unsigned long sp;
80 unsigned long pc;
81 };
82
83 static __always_inline unsigned long
84 ftrace_regs_get_instruction_pointer(const struct ftrace_regs *fregs)
85 {
86 return fregs->pc;
87 }
88
89 static __always_inline void
90 ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs,
91 unsigned long pc)
92 {
93 fregs->pc = pc;
94 }
95
96 static __always_inline unsigned long
97 ftrace_regs_get_stack_pointer(const struct ftrace_regs *fregs)
98 {
99 return fregs->sp;
100 }
101
102 static __always_inline unsigned long
103 ftrace_regs_get_argument(struct ftrace_regs *fregs, unsigned int n)
104 {
105 if (n < 8)
106 return fregs->regs[n];
107 return 0;
108 }
109
110 static __always_inline unsigned long
111 ftrace_regs_get_return_value(const struct ftrace_regs *fregs)
112 {
113 return fregs->regs[0];
114 }
115
116 static __always_inline void
117 ftrace_regs_set_return_value(struct ftrace_regs *fregs,
118 unsigned long ret)
119 {
120 fregs->regs[0] = ret;
121 }
122
123 static __always_inline void
124 ftrace_override_function_with_return(struct ftrace_regs *fregs)
125 {
126 fregs->pc = fregs->lr;
127 }
128
129 int ftrace_regs_query_register_offset(const char *name);
130
131 int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
132 #define ftrace_init_nop ftrace_init_nop
133
134 void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
135 struct ftrace_ops *op, struct ftrace_regs *fregs);
136 #define ftrace_graph_func ftrace_graph_func
137
138 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
139 static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs,
140 unsigned long addr)
141 {
142 /*
143 * The ftrace trampoline will return to this address instead of the
144 * instrumented function.
145 */
146 fregs->direct_tramp = addr;
147 }
148 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
149
150 #endif
151
152 #define ftrace_return_address(n) return_address(n)
153
154 /*
155 * Because AArch32 mode does not share the same syscall table with AArch64,
156 * tracing compat syscalls may result in reporting bogus syscalls or even
157 * hang-up, so just do not trace them.
158 * See kernel/trace/trace_syscalls.c
159 *
160 * x86 code says:
161 * If the user really wants these, then they should use the
162 * raw syscall tracepoints with filtering.
163 */
164 #define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
165 static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs)
166 {
167 return is_compat_task();
168 }
169
170 #define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
171
172 static inline bool arch_syscall_match_sym_name(const char *sym,
173 const char *name)
174 {
175 /*
176 * Since all syscall functions have __arm64_ prefix, we must skip it.
177 * However, as we described above, we decided to ignore compat
178 * syscalls, so we don't care about __arm64_compat_ prefix here.
179 */
180 return !strcmp(sym + 8, name);
181 }
182 #endif /* ifndef __ASSEMBLY__ */
183
184 #ifndef __ASSEMBLY__
185 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
186 struct fgraph_ret_regs {
187 /* x0 - x7 */
188 unsigned long regs[8];
189
190 unsigned long fp;
191 unsigned long __unused;
192 };
193
194 static inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret_regs *ret_regs)
195 {
196 return ret_regs->regs[0];
197 }
198
199 static inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_ret_regs *ret_regs)
200 {
201 return ret_regs->fp;
202 }
203
204 void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent,
205 unsigned long frame_pointer);
206
207 #endif /* ifdef CONFIG_FUNCTION_GRAPH_TRACER */
208 #endif
209
210 #endif /* __ASM_FTRACE_H */
211
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