xref: /openbmc/linux/arch/s390/kernel/mcount.S (revision 9a4f03ad6d67b63e7d2a3fe16c30511f5fb80040)
1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright IBM Corp. 2008, 2009
4 *
5 */
6
7#include <linux/linkage.h>
8#include <asm/asm-offsets.h>
9#include <asm/ftrace.h>
10#include <asm/nospec-insn.h>
11#include <asm/ptrace.h>
12#include <asm/export.h>
13
14	GEN_BR_THUNK %r1
15	GEN_BR_THUNK %r14
16
17	.section .kprobes.text, "ax"
18
19ENTRY(ftrace_stub)
20	BR_EX	%r14
21ENDPROC(ftrace_stub)
22
23#define STACK_FRAME_SIZE	(STACK_FRAME_OVERHEAD + __PT_SIZE)
24#define STACK_PTREGS		(STACK_FRAME_OVERHEAD)
25#define STACK_PTREGS_GPRS	(STACK_PTREGS + __PT_GPRS)
26#define STACK_PTREGS_PSW	(STACK_PTREGS + __PT_PSW)
27#define STACK_PTREGS_ORIG_GPR2	(STACK_PTREGS + __PT_ORIG_GPR2)
28#define STACK_PTREGS_FLAGS	(STACK_PTREGS + __PT_FLAGS)
29#ifdef __PACK_STACK
30/* allocate just enough for r14, r15 and backchain */
31#define TRACED_FUNC_FRAME_SIZE	24
32#else
33#define TRACED_FUNC_FRAME_SIZE	STACK_FRAME_OVERHEAD
34#endif
35
36	.macro	ftrace_regs_entry, allregs=0
37	stg	%r14,(__SF_GPRS+8*8)(%r15)	# save traced function caller
38
39	.if \allregs == 1
40	lghi	%r14,0				# save condition code
41	ipm	%r14				# don't put any instructions
42	sllg	%r14,%r14,16			# clobbering CC before this point
43	.endif
44
45	lgr	%r1,%r15
46	# allocate stack frame for ftrace_caller to contain traced function
47	aghi	%r15,-TRACED_FUNC_FRAME_SIZE
48	stg	%r1,__SF_BACKCHAIN(%r15)
49	stg	%r0,(__SF_GPRS+8*8)(%r15)
50	stg	%r15,(__SF_GPRS+9*8)(%r15)
51	# allocate pt_regs and stack frame for ftrace_trace_function
52	aghi	%r15,-STACK_FRAME_SIZE
53	stg	%r1,(STACK_PTREGS_GPRS+15*8)(%r15)
54	xc	STACK_PTREGS_ORIG_GPR2(8,%r15),STACK_PTREGS_ORIG_GPR2(%r15)
55
56	.if \allregs == 1
57	stg	%r14,(STACK_PTREGS_PSW)(%r15)
58	stosm	(STACK_PTREGS_PSW)(%r15),0
59#ifdef CONFIG_HAVE_MARCH_Z10_FEATURES
60	mvghi	STACK_PTREGS_FLAGS(%r15),_PIF_FTRACE_FULL_REGS
61#else
62	lghi	%r14,_PIF_FTRACE_FULL_REGS
63	stg	%r14,STACK_PTREGS_FLAGS(%r15)
64#endif
65	.else
66	xc	STACK_PTREGS_FLAGS(8,%r15),STACK_PTREGS_FLAGS(%r15)
67	.endif
68
69	lg	%r14,(__SF_GPRS+8*8)(%r1)	# restore original return address
70	aghi	%r1,-TRACED_FUNC_FRAME_SIZE
71	stg	%r1,__SF_BACKCHAIN(%r15)
72	stg	%r0,(STACK_PTREGS_PSW+8)(%r15)
73	stmg	%r2,%r14,(STACK_PTREGS_GPRS+2*8)(%r15)
74	.endm
75
76SYM_CODE_START(ftrace_regs_caller)
77	ftrace_regs_entry	1
78	j	ftrace_common
79SYM_CODE_END(ftrace_regs_caller)
80
81SYM_CODE_START(ftrace_caller)
82	ftrace_regs_entry	0
83	j	ftrace_common
84SYM_CODE_END(ftrace_caller)
85
86SYM_CODE_START(ftrace_common)
87#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
88	aghik	%r2,%r0,-MCOUNT_INSN_SIZE
89	lgrl	%r4,function_trace_op
90	lgrl	%r1,ftrace_func
91#else
92	lgr	%r2,%r0
93	aghi	%r2,-MCOUNT_INSN_SIZE
94	larl	%r4,function_trace_op
95	lg	%r4,0(%r4)
96	larl	%r1,ftrace_func
97	lg	%r1,0(%r1)
98#endif
99	lgr	%r3,%r14
100	la	%r5,STACK_PTREGS(%r15)
101	BASR_EX	%r14,%r1
102#ifdef CONFIG_FUNCTION_GRAPH_TRACER
103# The j instruction gets runtime patched to a nop instruction.
104# See ftrace_enable_ftrace_graph_caller.
105SYM_INNER_LABEL(ftrace_graph_caller, SYM_L_GLOBAL)
106	j	.Lftrace_graph_caller_end
107	lmg	%r2,%r3,(STACK_PTREGS_GPRS+14*8)(%r15)
108	lg	%r4,(STACK_PTREGS_PSW+8)(%r15)
109	brasl	%r14,prepare_ftrace_return
110	stg	%r2,(STACK_PTREGS_GPRS+14*8)(%r15)
111.Lftrace_graph_caller_end:
112#endif
113	lg	%r0,(STACK_PTREGS_PSW+8)(%r15)
114#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
115	ltg	%r1,STACK_PTREGS_ORIG_GPR2(%r15)
116	locgrz	%r1,%r0
117#else
118	lg	%r1,STACK_PTREGS_ORIG_GPR2(%r15)
119	ltgr	%r1,%r1
120	jnz	0f
121	lgr	%r1,%r0
122#endif
1230:	lmg	%r2,%r15,(STACK_PTREGS_GPRS+2*8)(%r15)
124	BR_EX	%r1
125SYM_CODE_END(ftrace_common)
126
127#ifdef CONFIG_FUNCTION_GRAPH_TRACER
128
129SYM_FUNC_START(return_to_handler)
130	stmg	%r2,%r5,32(%r15)
131	lgr	%r1,%r15
132	aghi	%r15,-STACK_FRAME_OVERHEAD
133	stg	%r1,__SF_BACKCHAIN(%r15)
134	brasl	%r14,ftrace_return_to_handler
135	aghi	%r15,STACK_FRAME_OVERHEAD
136	lgr	%r14,%r2
137	lmg	%r2,%r5,32(%r15)
138	BR_EX	%r14
139SYM_FUNC_END(return_to_handler)
140
141#endif
142