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_REGS
16#define ARCH_SUPPORTS_FTRACE_OPS 1
17#else
18#define MCOUNT_ADDR		((unsigned long)function_nocfi(_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 FTRACE_REGS_PLT_IDX	1
26#define NR_FTRACE_PLTS		2
27
28/*
29 * Currently, gcc tends to save the link register after the local variables
30 * on the stack. This causes the max stack tracer to report the function
31 * frame sizes for the wrong functions. By defining
32 * ARCH_FTRACE_SHIFT_STACK_TRACER, it will tell the stack tracer to expect
33 * to find the return address on the stack after the local variables have
34 * been set up.
35 *
36 * Note, this may change in the future, and we will need to deal with that
37 * if it were to happen.
38 */
39#define ARCH_FTRACE_SHIFT_STACK_TRACER 1
40
41#ifndef __ASSEMBLY__
42#include <linux/compat.h>
43
44extern void _mcount(unsigned long);
45extern void *return_address(unsigned int);
46
47struct dyn_arch_ftrace {
48	/* No extra data needed for arm64 */
49};
50
51extern unsigned long ftrace_graph_call;
52
53extern void return_to_handler(void);
54
55static inline unsigned long ftrace_call_adjust(unsigned long addr)
56{
57	/*
58	 * Adjust addr to point at the BL in the callsite.
59	 * See ftrace_init_nop() for the callsite sequence.
60	 */
61	if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS))
62		return addr + AARCH64_INSN_SIZE;
63	/*
64	 * addr is the address of the mcount call instruction.
65	 * recordmcount does the necessary offset calculation.
66	 */
67	return addr;
68}
69
70#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
71struct dyn_ftrace;
72int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
73#define ftrace_init_nop ftrace_init_nop
74#endif
75
76#define ftrace_return_address(n) return_address(n)
77
78/*
79 * Because AArch32 mode does not share the same syscall table with AArch64,
80 * tracing compat syscalls may result in reporting bogus syscalls or even
81 * hang-up, so just do not trace them.
82 * See kernel/trace/trace_syscalls.c
83 *
84 * x86 code says:
85 * If the user really wants these, then they should use the
86 * raw syscall tracepoints with filtering.
87 */
88#define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
89static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs)
90{
91	return is_compat_task();
92}
93
94#define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
95
96static inline bool arch_syscall_match_sym_name(const char *sym,
97					       const char *name)
98{
99	/*
100	 * Since all syscall functions have __arm64_ prefix, we must skip it.
101	 * However, as we described above, we decided to ignore compat
102	 * syscalls, so we don't care about __arm64_compat_ prefix here.
103	 */
104	return !strcmp(sym + 8, name);
105}
106#endif /* ifndef __ASSEMBLY__ */
107
108#endif /* __ASM_FTRACE_H */
109