1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | #include <linux/module.h> |
3 | #include <linux/kthread.h> |
4 | #include <linux/ftrace.h> |
5 | #ifndef CONFIG_ARM64 |
6 | #include <asm/asm-offsets.h> |
7 | #endif |
8 | |
9 | extern void my_direct_func1(unsigned long ip); |
10 | extern void my_direct_func2(unsigned long ip); |
11 | |
12 | void my_direct_func1(unsigned long ip) |
13 | { |
14 | trace_printk("my direct func1 ip %lx\n" , ip); |
15 | } |
16 | |
17 | void my_direct_func2(unsigned long ip) |
18 | { |
19 | trace_printk("my direct func2 ip %lx\n" , ip); |
20 | } |
21 | |
22 | extern void my_tramp1(void *); |
23 | extern void my_tramp2(void *); |
24 | |
25 | #ifdef CONFIG_RISCV |
26 | #include <asm/asm.h> |
27 | |
28 | asm ( |
29 | " .pushsection .text, \"ax\", @progbits\n" |
30 | " .type my_tramp1, @function\n" |
31 | " .globl my_tramp1\n" |
32 | " my_tramp1:\n" |
33 | " addi sp,sp,-3*" SZREG"\n" |
34 | " " REG_S" a0,0*" SZREG"(sp)\n" |
35 | " " REG_S" t0,1*" SZREG"(sp)\n" |
36 | " " REG_S" ra,2*" SZREG"(sp)\n" |
37 | " mv a0,t0\n" |
38 | " call my_direct_func1\n" |
39 | " " REG_L" a0,0*" SZREG"(sp)\n" |
40 | " " REG_L" t0,1*" SZREG"(sp)\n" |
41 | " " REG_L" ra,2*" SZREG"(sp)\n" |
42 | " addi sp,sp,3*" SZREG"\n" |
43 | " jr t0\n" |
44 | " .size my_tramp1, .-my_tramp1\n" |
45 | |
46 | " .type my_tramp2, @function\n" |
47 | " .globl my_tramp2\n" |
48 | " my_tramp2:\n" |
49 | " addi sp,sp,-3*" SZREG"\n" |
50 | " " REG_S" a0,0*" SZREG"(sp)\n" |
51 | " " REG_S" t0,1*" SZREG"(sp)\n" |
52 | " " REG_S" ra,2*" SZREG"(sp)\n" |
53 | " mv a0,t0\n" |
54 | " call my_direct_func2\n" |
55 | " " REG_L" a0,0*" SZREG"(sp)\n" |
56 | " " REG_L" t0,1*" SZREG"(sp)\n" |
57 | " " REG_L" ra,2*" SZREG"(sp)\n" |
58 | " addi sp,sp,3*" SZREG"\n" |
59 | " jr t0\n" |
60 | " .size my_tramp2, .-my_tramp2\n" |
61 | " .popsection\n" |
62 | ); |
63 | |
64 | #endif /* CONFIG_RISCV */ |
65 | |
66 | #ifdef CONFIG_X86_64 |
67 | |
68 | #include <asm/ibt.h> |
69 | #include <asm/nospec-branch.h> |
70 | |
71 | asm ( |
72 | " .pushsection .text, \"ax\", @progbits\n" |
73 | " .type my_tramp1, @function\n" |
74 | " .globl my_tramp1\n" |
75 | " my_tramp1:" |
76 | ASM_ENDBR |
77 | " pushq %rbp\n" |
78 | " movq %rsp, %rbp\n" |
79 | CALL_DEPTH_ACCOUNT |
80 | " pushq %rdi\n" |
81 | " movq 8(%rbp), %rdi\n" |
82 | " call my_direct_func1\n" |
83 | " popq %rdi\n" |
84 | " leave\n" |
85 | ASM_RET |
86 | " .size my_tramp1, .-my_tramp1\n" |
87 | |
88 | " .type my_tramp2, @function\n" |
89 | " .globl my_tramp2\n" |
90 | " my_tramp2:" |
91 | ASM_ENDBR |
92 | " pushq %rbp\n" |
93 | " movq %rsp, %rbp\n" |
94 | CALL_DEPTH_ACCOUNT |
95 | " pushq %rdi\n" |
96 | " movq 8(%rbp), %rdi\n" |
97 | " call my_direct_func2\n" |
98 | " popq %rdi\n" |
99 | " leave\n" |
100 | ASM_RET |
101 | " .size my_tramp2, .-my_tramp2\n" |
102 | " .popsection\n" |
103 | ); |
104 | |
105 | #endif /* CONFIG_X86_64 */ |
106 | |
107 | #ifdef CONFIG_S390 |
108 | |
109 | asm ( |
110 | " .pushsection .text, \"ax\", @progbits\n" |
111 | " .type my_tramp1, @function\n" |
112 | " .globl my_tramp1\n" |
113 | " my_tramp1:" |
114 | " lgr %r1,%r15\n" |
115 | " stmg %r0,%r5," __stringify(__SF_GPRS)"(%r15)\n" |
116 | " stg %r14," __stringify(__SF_GPRS+8*8)"(%r15)\n" |
117 | " aghi %r15," __stringify(-STACK_FRAME_OVERHEAD)"\n" |
118 | " stg %r1," __stringify(__SF_BACKCHAIN)"(%r15)\n" |
119 | " lgr %r2,%r0\n" |
120 | " brasl %r14,my_direct_func1\n" |
121 | " aghi %r15," __stringify(STACK_FRAME_OVERHEAD)"\n" |
122 | " lmg %r0,%r5," __stringify(__SF_GPRS)"(%r15)\n" |
123 | " lg %r14," __stringify(__SF_GPRS+8*8)"(%r15)\n" |
124 | " lgr %r1,%r0\n" |
125 | " br %r1\n" |
126 | " .size my_tramp1, .-my_tramp1\n" |
127 | "\n" |
128 | " .type my_tramp2, @function\n" |
129 | " .globl my_tramp2\n" |
130 | " my_tramp2:" |
131 | " lgr %r1,%r15\n" |
132 | " stmg %r0,%r5," __stringify(__SF_GPRS)"(%r15)\n" |
133 | " stg %r14," __stringify(__SF_GPRS+8*8)"(%r15)\n" |
134 | " aghi %r15," __stringify(-STACK_FRAME_OVERHEAD)"\n" |
135 | " stg %r1," __stringify(__SF_BACKCHAIN)"(%r15)\n" |
136 | " lgr %r2,%r0\n" |
137 | " brasl %r14,my_direct_func2\n" |
138 | " aghi %r15," __stringify(STACK_FRAME_OVERHEAD)"\n" |
139 | " lmg %r0,%r5," __stringify(__SF_GPRS)"(%r15)\n" |
140 | " lg %r14," __stringify(__SF_GPRS+8*8)"(%r15)\n" |
141 | " lgr %r1,%r0\n" |
142 | " br %r1\n" |
143 | " .size my_tramp2, .-my_tramp2\n" |
144 | " .popsection\n" |
145 | ); |
146 | |
147 | #endif /* CONFIG_S390 */ |
148 | |
149 | #ifdef CONFIG_ARM64 |
150 | |
151 | asm ( |
152 | " .pushsection .text, \"ax\", @progbits\n" |
153 | " .type my_tramp1, @function\n" |
154 | " .globl my_tramp1\n" |
155 | " my_tramp1:" |
156 | " hint 34\n" // bti c |
157 | " sub sp, sp, #32\n" |
158 | " stp x9, x30, [sp]\n" |
159 | " str x0, [sp, #16]\n" |
160 | " mov x0, x30\n" |
161 | " bl my_direct_func1\n" |
162 | " ldp x30, x9, [sp]\n" |
163 | " ldr x0, [sp, #16]\n" |
164 | " add sp, sp, #32\n" |
165 | " ret x9\n" |
166 | " .size my_tramp1, .-my_tramp1\n" |
167 | |
168 | " .type my_tramp2, @function\n" |
169 | " .globl my_tramp2\n" |
170 | " my_tramp2:" |
171 | " hint 34\n" // bti c |
172 | " sub sp, sp, #32\n" |
173 | " stp x9, x30, [sp]\n" |
174 | " str x0, [sp, #16]\n" |
175 | " mov x0, x30\n" |
176 | " bl my_direct_func2\n" |
177 | " ldp x30, x9, [sp]\n" |
178 | " ldr x0, [sp, #16]\n" |
179 | " add sp, sp, #32\n" |
180 | " ret x9\n" |
181 | " .size my_tramp2, .-my_tramp2\n" |
182 | " .popsection\n" |
183 | ); |
184 | |
185 | #endif /* CONFIG_ARM64 */ |
186 | |
187 | #ifdef CONFIG_LOONGARCH |
188 | #include <asm/asm.h> |
189 | |
190 | asm ( |
191 | " .pushsection .text, \"ax\", @progbits\n" |
192 | " .type my_tramp1, @function\n" |
193 | " .globl my_tramp1\n" |
194 | " my_tramp1:\n" |
195 | " addi.d $sp, $sp, -32\n" |
196 | " st.d $a0, $sp, 0\n" |
197 | " st.d $t0, $sp, 8\n" |
198 | " st.d $ra, $sp, 16\n" |
199 | " move $a0, $t0\n" |
200 | " bl my_direct_func1\n" |
201 | " ld.d $a0, $sp, 0\n" |
202 | " ld.d $t0, $sp, 8\n" |
203 | " ld.d $ra, $sp, 16\n" |
204 | " addi.d $sp, $sp, 32\n" |
205 | " jr $t0\n" |
206 | " .size my_tramp1, .-my_tramp1\n" |
207 | |
208 | " .type my_tramp2, @function\n" |
209 | " .globl my_tramp2\n" |
210 | " my_tramp2:\n" |
211 | " addi.d $sp, $sp, -32\n" |
212 | " st.d $a0, $sp, 0\n" |
213 | " st.d $t0, $sp, 8\n" |
214 | " st.d $ra, $sp, 16\n" |
215 | " move $a0, $t0\n" |
216 | " bl my_direct_func2\n" |
217 | " ld.d $a0, $sp, 0\n" |
218 | " ld.d $t0, $sp, 8\n" |
219 | " ld.d $ra, $sp, 16\n" |
220 | " addi.d $sp, $sp, 32\n" |
221 | " jr $t0\n" |
222 | " .size my_tramp2, .-my_tramp2\n" |
223 | " .popsection\n" |
224 | ); |
225 | |
226 | #endif /* CONFIG_LOONGARCH */ |
227 | |
228 | static unsigned long my_tramp = (unsigned long)my_tramp1; |
229 | static unsigned long tramps[2] = { |
230 | (unsigned long)my_tramp1, |
231 | (unsigned long)my_tramp2, |
232 | }; |
233 | |
234 | static struct ftrace_ops direct; |
235 | |
236 | static int simple_thread(void *arg) |
237 | { |
238 | static int t; |
239 | int ret = 0; |
240 | |
241 | while (!kthread_should_stop()) { |
242 | set_current_state(TASK_INTERRUPTIBLE); |
243 | schedule_timeout(timeout: 2 * HZ); |
244 | |
245 | if (ret) |
246 | continue; |
247 | t ^= 1; |
248 | ret = modify_ftrace_direct(ops: &direct, addr: tramps[t]); |
249 | if (!ret) |
250 | my_tramp = tramps[t]; |
251 | WARN_ON_ONCE(ret); |
252 | } |
253 | |
254 | return 0; |
255 | } |
256 | |
257 | static struct task_struct *simple_tsk; |
258 | |
259 | static int __init ftrace_direct_multi_init(void) |
260 | { |
261 | int ret; |
262 | |
263 | ftrace_set_filter_ip(ops: &direct, ip: (unsigned long) wake_up_process, remove: 0, reset: 0); |
264 | ftrace_set_filter_ip(ops: &direct, ip: (unsigned long) schedule, remove: 0, reset: 0); |
265 | |
266 | ret = register_ftrace_direct(ops: &direct, addr: my_tramp); |
267 | |
268 | if (!ret) |
269 | simple_tsk = kthread_run(simple_thread, NULL, "event-sample-fn" ); |
270 | return ret; |
271 | } |
272 | |
273 | static void __exit ftrace_direct_multi_exit(void) |
274 | { |
275 | kthread_stop(k: simple_tsk); |
276 | unregister_ftrace_direct(ops: &direct, addr: my_tramp, free_filters: true); |
277 | } |
278 | |
279 | module_init(ftrace_direct_multi_init); |
280 | module_exit(ftrace_direct_multi_exit); |
281 | |
282 | MODULE_AUTHOR("Jiri Olsa" ); |
283 | MODULE_DESCRIPTION("Example use case of using modify_ftrace_direct()" ); |
284 | MODULE_LICENSE("GPL" ); |
285 | |