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[linux.git] / samples / ftrace / ftrace-direct-multi.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 #include <linux/module.h>
3
4 #include <linux/mm.h> /* for handle_mm_fault() */
5 #include <linux/ftrace.h>
6 #include <linux/sched/stat.h>
7 #if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32)
8 #include <asm/asm-offsets.h>
9 #endif
10
11 extern void my_direct_func(unsigned long ip);
12
13 void my_direct_func(unsigned long ip)
14 {
15         trace_printk("ip %lx\n", ip);
16 }
17
18 extern void my_tramp(void *);
19
20 #ifdef CONFIG_RISCV
21 #include <asm/asm.h>
22
23 asm (
24 "       .pushsection    .text, \"ax\", @progbits\n"
25 "       .type           my_tramp, @function\n"
26 "       .globl          my_tramp\n"
27 "   my_tramp:\n"
28 "       addi    sp,sp,-3*"SZREG"\n"
29 "       "REG_S" a0,0*"SZREG"(sp)\n"
30 "       "REG_S" t0,1*"SZREG"(sp)\n"
31 "       "REG_S" ra,2*"SZREG"(sp)\n"
32 "       mv      a0,t0\n"
33 "       call    my_direct_func\n"
34 "       "REG_L" a0,0*"SZREG"(sp)\n"
35 "       "REG_L" t0,1*"SZREG"(sp)\n"
36 "       "REG_L" ra,2*"SZREG"(sp)\n"
37 "       addi    sp,sp,3*"SZREG"\n"
38 "       jr      t0\n"
39 "       .size           my_tramp, .-my_tramp\n"
40 "       .popsection\n"
41 );
42
43 #endif /* CONFIG_RISCV */
44
45 #ifdef CONFIG_X86_64
46
47 #include <asm/ibt.h>
48 #include <asm/nospec-branch.h>
49
50 asm (
51 "       .pushsection    .text, \"ax\", @progbits\n"
52 "       .type           my_tramp, @function\n"
53 "       .globl          my_tramp\n"
54 "   my_tramp:"
55         ASM_ENDBR
56 "       pushq %rbp\n"
57 "       movq %rsp, %rbp\n"
58         CALL_DEPTH_ACCOUNT
59 "       pushq %rdi\n"
60 "       movq 8(%rbp), %rdi\n"
61 "       call my_direct_func\n"
62 "       popq %rdi\n"
63 "       leave\n"
64         ASM_RET
65 "       .size           my_tramp, .-my_tramp\n"
66 "       .popsection\n"
67 );
68
69 #endif /* CONFIG_X86_64 */
70
71 #ifdef CONFIG_S390
72
73 asm (
74 "       .pushsection    .text, \"ax\", @progbits\n"
75 "       .type           my_tramp, @function\n"
76 "       .globl          my_tramp\n"
77 "   my_tramp:"
78 "       lgr             %r1,%r15\n"
79 "       stmg            %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
80 "       stg             %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
81 "       aghi            %r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
82 "       stg             %r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
83 "       lgr             %r2,%r0\n"
84 "       brasl           %r14,my_direct_func\n"
85 "       aghi            %r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
86 "       lmg             %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
87 "       lg              %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
88 "       lgr             %r1,%r0\n"
89 "       br              %r1\n"
90 "       .size           my_tramp, .-my_tramp\n"
91 "       .popsection\n"
92 );
93
94 #endif /* CONFIG_S390 */
95
96 #ifdef CONFIG_ARM64
97
98 asm (
99 "       .pushsection    .text, \"ax\", @progbits\n"
100 "       .type           my_tramp, @function\n"
101 "       .globl          my_tramp\n"
102 "   my_tramp:"
103 "       hint    34\n" // bti    c
104 "       sub     sp, sp, #32\n"
105 "       stp     x9, x30, [sp]\n"
106 "       str     x0, [sp, #16]\n"
107 "       mov     x0, x30\n"
108 "       bl      my_direct_func\n"
109 "       ldp     x30, x9, [sp]\n"
110 "       ldr     x0, [sp, #16]\n"
111 "       add     sp, sp, #32\n"
112 "       ret     x9\n"
113 "       .size           my_tramp, .-my_tramp\n"
114 "       .popsection\n"
115 );
116
117 #endif /* CONFIG_ARM64 */
118
119 #ifdef CONFIG_LOONGARCH
120
121 #include <asm/asm.h>
122 asm (
123 "       .pushsection    .text, \"ax\", @progbits\n"
124 "       .type           my_tramp, @function\n"
125 "       .globl          my_tramp\n"
126 "   my_tramp:\n"
127 "       addi.d  $sp, $sp, -32\n"
128 "       st.d    $a0, $sp, 0\n"
129 "       st.d    $t0, $sp, 8\n"
130 "       st.d    $ra, $sp, 16\n"
131 "       move    $a0, $t0\n"
132 "       bl      my_direct_func\n"
133 "       ld.d    $a0, $sp, 0\n"
134 "       ld.d    $t0, $sp, 8\n"
135 "       ld.d    $ra, $sp, 16\n"
136 "       addi.d  $sp, $sp, 32\n"
137 "       jr      $t0\n"
138 "       .size           my_tramp, .-my_tramp\n"
139 "       .popsection\n"
140 );
141
142 #endif /* CONFIG_LOONGARCH */
143
144 #ifdef CONFIG_PPC
145 #include <asm/ppc_asm.h>
146
147 #ifdef CONFIG_PPC64
148 #define STACK_FRAME_SIZE 48
149 #else
150 #define STACK_FRAME_SIZE 24
151 #endif
152
153 #if defined(CONFIG_PPC64_ELF_ABI_V2) && !defined(CONFIG_PPC_KERNEL_PCREL)
154 #define PPC64_TOC_SAVE_AND_UPDATE                       \
155 "       std             2, 24(1)\n"                     \
156 "       bcl             20, 31, 1f\n"                   \
157 "   1:  mflr            12\n"                           \
158 "       ld              2, (99f - 1b)(12)\n"
159 #define PPC64_TOC_RESTORE                               \
160 "       ld              2, 24(1)\n"
161 #define PPC64_TOC                                       \
162 "   99: .quad           .TOC.@tocbase\n"
163 #else
164 #define PPC64_TOC_SAVE_AND_UPDATE ""
165 #define PPC64_TOC_RESTORE ""
166 #define PPC64_TOC ""
167 #endif
168
169 #ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
170 #define PPC_FTRACE_RESTORE_LR                           \
171         PPC_LL"         0, "__stringify(PPC_LR_STKOFF)"(1)\n"   \
172 "       mtlr            0\n"
173 #define PPC_FTRACE_RET                                  \
174 "       blr\n"
175 #define PPC_FTRACE_RECOVER_IP                           \
176 "       lwz             8, 4(3)\n"                      \
177 "       li              9, 6\n"                         \
178 "       slw             8, 8, 9\n"                      \
179 "       sraw            8, 8, 9\n"                      \
180 "       add             3, 3, 8\n"                      \
181 "       addi            3, 3, 4\n"
182 #else
183 #define PPC_FTRACE_RESTORE_LR                           \
184         PPC_LL"         0, "__stringify(PPC_LR_STKOFF)"(1)\n"   \
185 "       mtctr           0\n"
186 #define PPC_FTRACE_RET                                  \
187 "       mtlr            0\n"                            \
188 "       bctr\n"
189 #define PPC_FTRACE_RECOVER_IP ""
190 #endif
191
192 asm (
193 "       .pushsection    .text, \"ax\", @progbits\n"
194 "       .type           my_tramp, @function\n"
195 "       .globl          my_tramp\n"
196 "   my_tramp:\n"
197         PPC_STL"        0, "__stringify(PPC_LR_STKOFF)"(1)\n"
198         PPC_STLU"       1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"
199 "       mflr            0\n"
200         PPC_STL"        0, "__stringify(PPC_LR_STKOFF)"(1)\n"
201         PPC_STLU"       1, -"__stringify(STACK_FRAME_SIZE)"(1)\n"
202         PPC64_TOC_SAVE_AND_UPDATE
203         PPC_STL"        3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"
204 "       mr              3, 0\n"
205         PPC_FTRACE_RECOVER_IP
206 "       bl              my_direct_func\n"
207         PPC_LL"         3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"
208         PPC64_TOC_RESTORE
209 "       addi            1, 1, "__stringify(STACK_FRAME_SIZE)"\n"
210         PPC_FTRACE_RESTORE_LR
211 "       addi            1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n"
212         PPC_LL"         0, "__stringify(PPC_LR_STKOFF)"(1)\n"
213         PPC_FTRACE_RET
214         PPC64_TOC
215 "       .size           my_tramp, .-my_tramp\n"
216 "       .popsection\n"
217 );
218
219 #endif /* CONFIG_PPC */
220
221 static struct ftrace_ops direct;
222
223 static int __init ftrace_direct_multi_init(void)
224 {
225         ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0);
226         ftrace_set_filter_ip(&direct, (unsigned long) schedule, 0, 0);
227
228         return register_ftrace_direct(&direct, (unsigned long) my_tramp);
229 }
230
231 static void __exit ftrace_direct_multi_exit(void)
232 {
233         unregister_ftrace_direct(&direct, (unsigned long) my_tramp, true);
234 }
235
236 module_init(ftrace_direct_multi_init);
237 module_exit(ftrace_direct_multi_exit);
238
239 MODULE_AUTHOR("Jiri Olsa");
240 MODULE_DESCRIPTION("Example use case of using register_ftrace_direct_multi()");
241 MODULE_LICENSE("GPL");
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