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)_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
44 extern void _mcount(unsigned long);
45 extern void *return_address(unsigned int);
46
47 struct dyn_arch_ftrace {
48 /* No extra data needed for arm64 */
49 };
50
51 extern unsigned long ftrace_graph_call;
52
53 extern void return_to_handler(void);
54
ftrace_call_adjust(unsigned long addr)55 static 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
71 struct dyn_ftrace;
72 int 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
arch_trace_is_compat_syscall(struct pt_regs * regs)89 static 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
arch_syscall_match_sym_name(const char * sym,const char * name)96 static 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