xref: /openbmc/linux/arch/s390/include/asm/ftrace.h (revision 94cdda6b)
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 #define ftrace_return_address(n) __builtin_return_address(n)
16 
17 void _mcount(void);
18 void ftrace_caller(void);
19 
20 extern char ftrace_graph_caller_end;
21 extern unsigned long ftrace_plt;
22 
23 struct dyn_arch_ftrace { };
24 
25 #define MCOUNT_ADDR ((unsigned long)_mcount)
26 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
27 
28 #define KPROBE_ON_FTRACE_NOP	0
29 #define KPROBE_ON_FTRACE_CALL	1
30 
31 static inline unsigned long ftrace_call_adjust(unsigned long addr)
32 {
33 	return addr;
34 }
35 
36 struct ftrace_insn {
37 	u16 opc;
38 	s32 disp;
39 } __packed;
40 
41 static inline void ftrace_generate_nop_insn(struct ftrace_insn *insn)
42 {
43 #ifdef CONFIG_FUNCTION_TRACER
44 #ifdef CC_USING_HOTPATCH
45 	/* brcl 0,0 */
46 	insn->opc = 0xc004;
47 	insn->disp = 0;
48 #else
49 	/* jg .+24 */
50 	insn->opc = 0xc0f4;
51 	insn->disp = MCOUNT_INSN_SIZE / 2;
52 #endif
53 #endif
54 }
55 
56 static inline int is_ftrace_nop(struct ftrace_insn *insn)
57 {
58 #ifdef CONFIG_FUNCTION_TRACER
59 #ifdef CC_USING_HOTPATCH
60 	if (insn->disp == 0)
61 		return 1;
62 #else
63 	if (insn->disp == MCOUNT_INSN_SIZE / 2)
64 		return 1;
65 #endif
66 #endif
67 	return 0;
68 }
69 
70 static inline void ftrace_generate_call_insn(struct ftrace_insn *insn,
71 					     unsigned long ip)
72 {
73 #ifdef CONFIG_FUNCTION_TRACER
74 	unsigned long target;
75 
76 	/* brasl r0,ftrace_caller */
77 	target = is_module_addr((void *) ip) ? ftrace_plt : FTRACE_ADDR;
78 	insn->opc = 0xc005;
79 	insn->disp = (target - ip) / 2;
80 #endif
81 }
82 
83 #endif /* __ASSEMBLY__ */
84 #endif /* _ASM_S390_FTRACE_H */
85