summaryrefslogtreecommitdiffstats
path: root/arch/arm64/include/asm/ftrace.h
blob: 1c2672bbbf37941d6be90c55041beda2af109c8d (plain)
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
161
162
163
164
165
166
167
168
169
170
171
172
173
/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * arch/arm64/include/asm/ftrace.h
 *
 * Copyright (C) 2013 Linaro Limited
 * Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
 */
#ifndef __ASM_FTRACE_H
#define __ASM_FTRACE_H

#include <asm/insn.h>

#define HAVE_FUNCTION_GRAPH_FP_TEST

/*
 * HAVE_FUNCTION_GRAPH_RET_ADDR_PTR means that the architecture can provide a
 * "return address pointer" which can be used to uniquely identify a return
 * address which has been overwritten.
 *
 * On arm64 we use the address of the caller's frame record, which remains the
 * same for the lifetime of the instrumented function, unlike the return
 * address in the LR.
 */
#define HAVE_FUNCTION_GRAPH_RET_ADDR_PTR

#ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
#define ARCH_SUPPORTS_FTRACE_OPS 1
#else
#define MCOUNT_ADDR		((unsigned long)_mcount)
#endif

/* The BL at the callsite's adjusted rec->ip */
#define MCOUNT_INSN_SIZE	AARCH64_INSN_SIZE

#define FTRACE_PLT_IDX		0
#define NR_FTRACE_PLTS		1

/*
 * Currently, gcc tends to save the link register after the local variables
 * on the stack. This causes the max stack tracer to report the function
 * frame sizes for the wrong functions. By defining
 * ARCH_FTRACE_SHIFT_STACK_TRACER, it will tell the stack tracer to expect
 * to find the return address on the stack after the local variables have
 * been set up.
 *
 * Note, this may change in the future, and we will need to deal with that
 * if it were to happen.
 */
#define ARCH_FTRACE_SHIFT_STACK_TRACER 1

#ifndef __ASSEMBLY__
#include <linux/compat.h>

extern void _mcount(unsigned long);
extern void *return_address(unsigned int);

struct dyn_arch_ftrace {
	/* No extra data needed for arm64 */
};

extern unsigned long ftrace_graph_call;

extern void return_to_handler(void);

unsigned long ftrace_call_adjust(unsigned long addr);

#ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
struct dyn_ftrace;
struct ftrace_ops;

#define arch_ftrace_get_regs(regs) NULL

struct ftrace_regs {
	/* x0 - x8 */
	unsigned long regs[9];
	unsigned long __unused;

	unsigned long fp;
	unsigned long lr;

	unsigned long sp;
	unsigned long pc;
};

static __always_inline unsigned long
ftrace_regs_get_instruction_pointer(const struct ftrace_regs *fregs)
{
	return fregs->pc;
}

static __always_inline void
ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs,
				    unsigned long pc)
{
	fregs->pc = pc;
}

static __always_inline unsigned long
ftrace_regs_get_stack_pointer(const struct ftrace_regs *fregs)
{
	return fregs->sp;
}

static __always_inline unsigned long
ftrace_regs_get_argument(struct ftrace_regs *fregs, unsigned int n)
{
	if (n < 8)
		return fregs->regs[n];
	return 0;
}

static __always_inline unsigned long
ftrace_regs_get_return_value(const struct ftrace_regs *fregs)
{
	return fregs->regs[0];
}

static __always_inline void
ftrace_regs_set_return_value(struct ftrace_regs *fregs,
			     unsigned long ret)
{
	fregs->regs[0] = ret;
}

static __always_inline void
ftrace_override_function_with_return(struct ftrace_regs *fregs)
{
	fregs->pc = fregs->lr;
}

int ftrace_regs_query_register_offset(const char *name);

int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
#define ftrace_init_nop ftrace_init_nop

void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
		       struct ftrace_ops *op, struct ftrace_regs *fregs);
#define ftrace_graph_func ftrace_graph_func
#endif

#define ftrace_return_address(n) return_address(n)

/*
 * Because AArch32 mode does not share the same syscall table with AArch64,
 * tracing compat syscalls may result in reporting bogus syscalls or even
 * hang-up, so just do not trace them.
 * See kernel/trace/trace_syscalls.c
 *
 * x86 code says:
 * If the user really wants these, then they should use the
 * raw syscall tracepoints with filtering.
 */
#define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs)
{
	return is_compat_task();
}

#define ARCH_HAS_SYSCALL_MATCH_SYM_NAME

static inline bool arch_syscall_match_sym_name(const char *sym,
					       const char *name)
{
	/*
	 * Since all syscall functions have __arm64_ prefix, we must skip it.
	 * However, as we described above, we decided to ignore compat
	 * syscalls, so we don't care about __arm64_compat_ prefix here.
	 */
	return !strcmp(sym + 8, name);
}
#endif /* ifndef __ASSEMBLY__ */

#endif /* __ASM_FTRACE_H */