1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_S390_FTRACE_H
3#define _ASM_S390_FTRACE_H
4
5#define ARCH_SUPPORTS_FTRACE_OPS 1
6
7#if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)
8#define MCOUNT_INSN_SIZE	6
9#else
10#define MCOUNT_INSN_SIZE	24
11#define MCOUNT_RETURN_FIXUP	18
12#endif
13
14#define HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
15
16#ifndef __ASSEMBLY__
17
18#ifdef CONFIG_CC_IS_CLANG
19/* https://bugs.llvm.org/show_bug.cgi?id=41424 */
20#define ftrace_return_address(n) 0UL
21#else
22#define ftrace_return_address(n) __builtin_return_address(n)
23#endif
24
25void _mcount(void);
26void ftrace_caller(void);
27
28extern char ftrace_graph_caller_end;
29extern unsigned long ftrace_plt;
30extern void *ftrace_func;
31
32struct dyn_arch_ftrace { };
33
34#define MCOUNT_ADDR ((unsigned long)_mcount)
35#define FTRACE_ADDR ((unsigned long)ftrace_caller)
36
37#define KPROBE_ON_FTRACE_NOP	0
38#define KPROBE_ON_FTRACE_CALL	1
39
40static inline unsigned long ftrace_call_adjust(unsigned long addr)
41{
42	return addr;
43}
44
45struct ftrace_insn {
46	u16 opc;
47	s32 disp;
48} __packed;
49
50static inline void ftrace_generate_nop_insn(struct ftrace_insn *insn)
51{
52#ifdef CONFIG_FUNCTION_TRACER
53#if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)
54	/* brcl 0,0 */
55	insn->opc = 0xc004;
56	insn->disp = 0;
57#else
58	/* jg .+24 */
59	insn->opc = 0xc0f4;
60	insn->disp = MCOUNT_INSN_SIZE / 2;
61#endif
62#endif
63}
64
65static inline int is_ftrace_nop(struct ftrace_insn *insn)
66{
67#ifdef CONFIG_FUNCTION_TRACER
68#if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)
69	if (insn->disp == 0)
70		return 1;
71#else
72	if (insn->disp == MCOUNT_INSN_SIZE / 2)
73		return 1;
74#endif
75#endif
76	return 0;
77}
78
79static inline void ftrace_generate_call_insn(struct ftrace_insn *insn,
80					     unsigned long ip)
81{
82#ifdef CONFIG_FUNCTION_TRACER
83	unsigned long target;
84
85	/* brasl r0,ftrace_caller */
86	target = is_module_addr((void *) ip) ? ftrace_plt : FTRACE_ADDR;
87	insn->opc = 0xc005;
88	insn->disp = (target - ip) / 2;
89#endif
90}
91
92/*
93 * Even though the system call numbers are identical for s390/s390x a
94 * different system call table is used for compat tasks. This may lead
95 * to e.g. incorrect or missing trace event sysfs files.
96 * Therefore simply do not trace compat system calls at all.
97 * See kernel/trace/trace_syscalls.c.
98 */
99#define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
100static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs)
101{
102	return is_compat_task();
103}
104
105#define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
106static inline bool arch_syscall_match_sym_name(const char *sym,
107					       const char *name)
108{
109	/*
110	 * Skip __s390_ and __s390x_ prefix - due to compat wrappers
111	 * and aliasing some symbols of 64 bit system call functions
112	 * may get the __s390_ prefix instead of the __s390x_ prefix.
113	 */
114	return !strcmp(sym + 7, name) || !strcmp(sym + 8, name);
115}
116
117#endif /* __ASSEMBLY__ */
118#endif /* _ASM_S390_FTRACE_H */
119