xref: /openbmc/linux/arch/s390/include/asm/ftrace.h (revision 62e59c4e)
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 #ifndef __ASSEMBLY__
15 
16 #define ftrace_return_address(n) __builtin_return_address(n)
17 
18 void _mcount(void);
19 void ftrace_caller(void);
20 
21 extern char ftrace_graph_caller_end;
22 extern unsigned long ftrace_plt;
23 
24 struct dyn_arch_ftrace { };
25 
26 #define MCOUNT_ADDR ((unsigned long)_mcount)
27 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
28 
29 #define KPROBE_ON_FTRACE_NOP	0
30 #define KPROBE_ON_FTRACE_CALL	1
31 
32 static inline unsigned long ftrace_call_adjust(unsigned long addr)
33 {
34 	return addr;
35 }
36 
37 struct ftrace_insn {
38 	u16 opc;
39 	s32 disp;
40 } __packed;
41 
42 static inline void ftrace_generate_nop_insn(struct ftrace_insn *insn)
43 {
44 #ifdef CONFIG_FUNCTION_TRACER
45 #if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)
46 	/* brcl 0,0 */
47 	insn->opc = 0xc004;
48 	insn->disp = 0;
49 #else
50 	/* jg .+24 */
51 	insn->opc = 0xc0f4;
52 	insn->disp = MCOUNT_INSN_SIZE / 2;
53 #endif
54 #endif
55 }
56 
57 static inline int is_ftrace_nop(struct ftrace_insn *insn)
58 {
59 #ifdef CONFIG_FUNCTION_TRACER
60 #if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)
61 	if (insn->disp == 0)
62 		return 1;
63 #else
64 	if (insn->disp == MCOUNT_INSN_SIZE / 2)
65 		return 1;
66 #endif
67 #endif
68 	return 0;
69 }
70 
71 static inline void ftrace_generate_call_insn(struct ftrace_insn *insn,
72 					     unsigned long ip)
73 {
74 #ifdef CONFIG_FUNCTION_TRACER
75 	unsigned long target;
76 
77 	/* brasl r0,ftrace_caller */
78 	target = is_module_addr((void *) ip) ? ftrace_plt : FTRACE_ADDR;
79 	insn->opc = 0xc005;
80 	insn->disp = (target - ip) / 2;
81 #endif
82 }
83 
84 /*
85  * Even though the system call numbers are identical for s390/s390x a
86  * different system call table is used for compat tasks. This may lead
87  * to e.g. incorrect or missing trace event sysfs files.
88  * Therefore simply do not trace compat system calls at all.
89  * See kernel/trace/trace_syscalls.c.
90  */
91 #define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
92 static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs)
93 {
94 	return is_compat_task();
95 }
96 
97 #define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
98 static inline bool arch_syscall_match_sym_name(const char *sym,
99 					       const char *name)
100 {
101 	/*
102 	 * Skip __s390_ and __s390x_ prefix - due to compat wrappers
103 	 * and aliasing some symbols of 64 bit system call functions
104 	 * may get the __s390_ prefix instead of the __s390x_ prefix.
105 	 */
106 	return !strcmp(sym + 7, name) || !strcmp(sym + 8, name);
107 }
108 
109 #endif /* __ASSEMBLY__ */
110 #endif /* _ASM_S390_FTRACE_H */
111