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/march.h>
13
14#define STACK_FRAME_SIZE_PTREGS (STACK_FRAME_OVERHEAD + __PT_SIZE)
15#define STACK_PTREGS (STACK_FRAME_OVERHEAD)
16#define STACK_PTREGS_GPRS (STACK_PTREGS + __PT_GPRS)
17#define STACK_PTREGS_PSW (STACK_PTREGS + __PT_PSW)
18
19#define STACK_FRAME_SIZE_FREGS (STACK_FRAME_OVERHEAD + __FTRACE_REGS_SIZE)
20#define STACK_FREGS (STACK_FRAME_OVERHEAD)
21#define STACK_FREGS_PTREGS (STACK_FRAME_OVERHEAD + __FTRACE_REGS_PT_REGS)
22#define STACK_FREGS_PTREGS_GPRS (STACK_FREGS_PTREGS + __PT_GPRS)
23#define STACK_FREGS_PTREGS_PSW (STACK_FREGS_PTREGS + __PT_PSW)
24#define STACK_FREGS_PTREGS_ORIG_GPR2 (STACK_FREGS_PTREGS + __PT_ORIG_GPR2)
25#define STACK_FREGS_PTREGS_FLAGS (STACK_FREGS_PTREGS + __PT_FLAGS)
26
27/* packed stack: allocate just enough for r14, r15 and backchain */
28#define TRACED_FUNC_FRAME_SIZE 24
29
30#ifdef CONFIG_FUNCTION_TRACER
31
32 GEN_BR_THUNK %r1
33 GEN_BR_THUNK %r14
34
35 .section .kprobes.text, "ax"
36
37SYM_FUNC_START(ftrace_stub)
38 BR_EX %r14
39SYM_FUNC_END(ftrace_stub)
40
41SYM_CODE_START(ftrace_stub_direct_tramp)
42 lgr %r1, %r0
43 BR_EX %r1
44SYM_CODE_END(ftrace_stub_direct_tramp)
45
46 .macro ftrace_regs_entry, allregs=0
47 stg %r14,(__SF_GPRS+8*8)(%r15) # save traced function caller
48
49 .if \allregs == 1
50 # save psw mask
51 # don't put any instructions clobbering CC before this point
52 epsw %r1,%r14
53 risbg %r14,%r1,0,31,32
54 .endif
55
56 lgr %r1,%r15
57 # allocate stack frame for ftrace_caller to contain traced function
58 aghi %r15,-TRACED_FUNC_FRAME_SIZE
59 stg %r1,__SF_BACKCHAIN(%r15)
60 stg %r0,(__SF_GPRS+8*8)(%r15)
61 stg %r15,(__SF_GPRS+9*8)(%r15)
62 # allocate ftrace_regs and stack frame for ftrace_trace_function
63 aghi %r15,-STACK_FRAME_SIZE_FREGS
64 stg %r1,(STACK_FREGS_PTREGS_GPRS+15*8)(%r15)
65 xc STACK_FREGS_PTREGS_ORIG_GPR2(8,%r15),STACK_FREGS_PTREGS_ORIG_GPR2(%r15)
66
67 .if \allregs == 1
68 stg %r14,(STACK_FREGS_PTREGS_PSW)(%r15)
69 mvghi STACK_FREGS_PTREGS_FLAGS(%r15),_PIF_FTRACE_FULL_REGS
70 .else
71 xc STACK_FREGS_PTREGS_FLAGS(8,%r15),STACK_FREGS_PTREGS_FLAGS(%r15)
72 .endif
73
74 lg %r14,(__SF_GPRS+8*8)(%r1) # restore original return address
75 aghi %r1,-TRACED_FUNC_FRAME_SIZE
76 stg %r1,__SF_BACKCHAIN(%r15)
77 stg %r0,(STACK_FREGS_PTREGS_PSW+8)(%r15)
78 stmg %r2,%r14,(STACK_FREGS_PTREGS_GPRS+2*8)(%r15)
79 .endm
80
81SYM_CODE_START(ftrace_regs_caller)
82 ftrace_regs_entry 1
83 j ftrace_common
84SYM_CODE_END(ftrace_regs_caller)
85
86SYM_CODE_START(ftrace_caller)
87 ftrace_regs_entry 0
88 j ftrace_common
89SYM_CODE_END(ftrace_caller)
90
91SYM_CODE_START(ftrace_common)
92#ifdef MARCH_HAS_Z196_FEATURES
93 aghik %r2,%r0,-MCOUNT_INSN_SIZE
94 lgrl %r4,function_trace_op
95 lgrl %r1,ftrace_func
96#else
97 lgr %r2,%r0
98 aghi %r2,-MCOUNT_INSN_SIZE
99 larl %r4,function_trace_op
100 lg %r4,0(%r4)
101 larl %r1,ftrace_func
102 lg %r1,0(%r1)
103#endif
104 lgr %r3,%r14
105 la %r5,STACK_FREGS(%r15)
106 BASR_EX %r14,%r1
107 lg %r0,(STACK_FREGS_PTREGS_PSW+8)(%r15)
108#ifdef MARCH_HAS_Z196_FEATURES
109 ltg %r1,STACK_FREGS_PTREGS_ORIG_GPR2(%r15)
110 locgrz %r1,%r0
111#else
112 lg %r1,STACK_FREGS_PTREGS_ORIG_GPR2(%r15)
113 ltgr %r1,%r1
114 jnz 0f
115 lgr %r1,%r0
116#endif
1170: lmg %r2,%r15,(STACK_FREGS_PTREGS_GPRS+2*8)(%r15)
118 BR_EX %r1
119SYM_CODE_END(ftrace_common)
120
121#ifdef CONFIG_FUNCTION_GRAPH_TRACER
122
123SYM_FUNC_START(return_to_handler)
124 stmg %r2,%r5,32(%r15)
125 lgr %r1,%r15
126 # allocate ftrace_regs and stack frame for ftrace_return_to_handler
127 aghi %r15,-STACK_FRAME_SIZE_FREGS
128 stg %r1,__SF_BACKCHAIN(%r15)
129 stg %r2,(STACK_FREGS_PTREGS_GPRS+2*8)(%r15)
130 stg %r1,(STACK_FREGS_PTREGS_GPRS+15*8)(%r15)
131 la %r2,STACK_FRAME_OVERHEAD(%r15)
132 brasl %r14,ftrace_return_to_handler
133 aghi %r15,STACK_FRAME_SIZE_FREGS
134 lgr %r14,%r2
135 lmg %r2,%r5,32(%r15)
136 BR_EX %r14
137SYM_FUNC_END(return_to_handler)
138
139#endif
140#endif /* CONFIG_FUNCTION_TRACER */
141
142SYM_CODE_START(ftrace_shared_hotpatch_trampoline_br)
143 lmg %r0,%r1,2(%r1)
144 br %r1
145SYM_INNER_LABEL(ftrace_shared_hotpatch_trampoline_br_end, SYM_L_GLOBAL)
146SYM_CODE_END(ftrace_shared_hotpatch_trampoline_br)
147
148#ifdef CONFIG_EXPOLINE
149SYM_CODE_START(ftrace_shared_hotpatch_trampoline_exrl)
150 lmg %r0,%r1,2(%r1)
151 exrl %r0,0f
152 j .
1530: br %r1
154SYM_INNER_LABEL(ftrace_shared_hotpatch_trampoline_exrl_end, SYM_L_GLOBAL)
155SYM_CODE_END(ftrace_shared_hotpatch_trampoline_exrl)
156#endif /* CONFIG_EXPOLINE */
157
158#ifdef CONFIG_RETHOOK
159
160SYM_CODE_START(arch_rethook_trampoline)
161 stg %r14,(__SF_GPRS+8*8)(%r15)
162 lay %r15,-STACK_FRAME_SIZE_PTREGS(%r15)
163 stmg %r0,%r14,STACK_PTREGS_GPRS(%r15)
164
165 # store original stack pointer in backchain and pt_regs
166 lay %r7,STACK_FRAME_SIZE_PTREGS(%r15)
167 stg %r7,__SF_BACKCHAIN(%r15)
168 stg %r7,STACK_PTREGS_GPRS+(15*8)(%r15)
169
170 # store full psw
171 epsw %r2,%r3
172 risbg %r3,%r2,0,31,32
173 stg %r3,STACK_PTREGS_PSW(%r15)
174 larl %r1,arch_rethook_trampoline
175 stg %r1,STACK_PTREGS_PSW+8(%r15)
176
177 lay %r2,STACK_PTREGS(%r15)
178 brasl %r14,arch_rethook_trampoline_callback
179
180 mvc __SF_EMPTY(16,%r7),STACK_PTREGS_PSW(%r15)
181 lmg %r0,%r15,STACK_PTREGS_GPRS(%r15)
182 lpswe __SF_EMPTY(%r15)
183SYM_CODE_END(arch_rethook_trampoline)
184
185#endif /* CONFIG_RETHOOK */
186

source code of linux/arch/s390/kernel/mcount.S