xref: /openbmc/linux/arch/s390/include/asm/ftrace.h (revision a77e393c)
1 #ifndef _ASM_S390_FTRACE_H
2 #define _ASM_S390_FTRACE_H
3 
4 #define ARCH_SUPPORTS_FTRACE_OPS 1
5 
6 #ifdef CC_USING_HOTPATCH
7 #define MCOUNT_INSN_SIZE	6
8 #else
9 #define MCOUNT_INSN_SIZE	24
10 #define MCOUNT_RETURN_FIXUP	18
11 #endif
12 
13 #ifndef __ASSEMBLY__
14 
15 unsigned long return_address(int depth);
16 
17 #define ftrace_return_address(n) return_address(n)
18 
19 void _mcount(void);
20 void ftrace_caller(void);
21 
22 extern char ftrace_graph_caller_end;
23 extern unsigned long ftrace_plt;
24 
25 struct dyn_arch_ftrace { };
26 
27 #define MCOUNT_ADDR ((unsigned long)_mcount)
28 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
29 
30 #define KPROBE_ON_FTRACE_NOP	0
31 #define KPROBE_ON_FTRACE_CALL	1
32 
33 static inline unsigned long ftrace_call_adjust(unsigned long addr)
34 {
35 	return addr;
36 }
37 
38 struct ftrace_insn {
39 	u16 opc;
40 	s32 disp;
41 } __packed;
42 
43 static inline void ftrace_generate_nop_insn(struct ftrace_insn *insn)
44 {
45 #ifdef CONFIG_FUNCTION_TRACER
46 #ifdef CC_USING_HOTPATCH
47 	/* brcl 0,0 */
48 	insn->opc = 0xc004;
49 	insn->disp = 0;
50 #else
51 	/* jg .+24 */
52 	insn->opc = 0xc0f4;
53 	insn->disp = MCOUNT_INSN_SIZE / 2;
54 #endif
55 #endif
56 }
57 
58 static inline int is_ftrace_nop(struct ftrace_insn *insn)
59 {
60 #ifdef CONFIG_FUNCTION_TRACER
61 #ifdef CC_USING_HOTPATCH
62 	if (insn->disp == 0)
63 		return 1;
64 #else
65 	if (insn->disp == MCOUNT_INSN_SIZE / 2)
66 		return 1;
67 #endif
68 #endif
69 	return 0;
70 }
71 
72 static inline void ftrace_generate_call_insn(struct ftrace_insn *insn,
73 					     unsigned long ip)
74 {
75 #ifdef CONFIG_FUNCTION_TRACER
76 	unsigned long target;
77 
78 	/* brasl r0,ftrace_caller */
79 	target = is_module_addr((void *) ip) ? ftrace_plt : FTRACE_ADDR;
80 	insn->opc = 0xc005;
81 	insn->disp = (target - ip) / 2;
82 #endif
83 }
84 
85 #endif /* __ASSEMBLY__ */
86 #endif /* _ASM_S390_FTRACE_H */
87