Commit | Line | Data |
---|---|---|
4e491d14 SR |
1 | /* |
2 | * Code for replacing ftrace calls with jumps. | |
3 | * | |
4 | * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> | |
5 | * | |
6 | * Thanks goes out to P.A. Semi, Inc for supplying me with a PPC64 box. | |
7 | * | |
6794c782 SR |
8 | * Added function graph tracer code, taken from x86 that was written |
9 | * by Frederic Weisbecker, and ported to PPC by Steven Rostedt. | |
10 | * | |
4e491d14 SR |
11 | */ |
12 | ||
13 | #include <linux/spinlock.h> | |
14 | #include <linux/hardirq.h> | |
e4486fe3 | 15 | #include <linux/uaccess.h> |
f48cb8b4 | 16 | #include <linux/module.h> |
4e491d14 SR |
17 | #include <linux/ftrace.h> |
18 | #include <linux/percpu.h> | |
19 | #include <linux/init.h> | |
20 | #include <linux/list.h> | |
21 | ||
22 | #include <asm/cacheflush.h> | |
f48cb8b4 | 23 | #include <asm/code-patching.h> |
395a59d0 | 24 | #include <asm/ftrace.h> |
02424d89 | 25 | #include <asm/syscall.h> |
4e491d14 | 26 | |
4e491d14 | 27 | |
6794c782 | 28 | #ifdef CONFIG_DYNAMIC_FTRACE |
b54dcfe1 | 29 | static unsigned int |
46542888 | 30 | ftrace_call_replace(unsigned long ip, unsigned long addr, int link) |
4e491d14 | 31 | { |
b54dcfe1 | 32 | unsigned int op; |
4e491d14 | 33 | |
4a9e3f8e | 34 | addr = ppc_function_entry((void *)addr); |
4e491d14 | 35 | |
46542888 | 36 | /* if (link) set op to 'bl' else 'b' */ |
bb9b9035 | 37 | op = create_branch((unsigned int *)ip, addr, link ? 1 : 0); |
4e491d14 | 38 | |
b54dcfe1 | 39 | return op; |
4e491d14 SR |
40 | } |
41 | ||
8fd6e5a8 | 42 | static int |
b54dcfe1 | 43 | ftrace_modify_code(unsigned long ip, unsigned int old, unsigned int new) |
4e491d14 | 44 | { |
b54dcfe1 | 45 | unsigned int replaced; |
4e491d14 | 46 | |
4e491d14 SR |
47 | /* |
48 | * Note: Due to modules and __init, code can | |
49 | * disappear and change, we need to protect against faulting | |
e4486fe3 SR |
50 | * as well as code changing. We do this by using the |
51 | * probe_kernel_* functions. | |
4e491d14 SR |
52 | * |
53 | * No real locking needed, this code is run through | |
e4486fe3 | 54 | * kstop_machine, or before SMP starts. |
4e491d14 | 55 | */ |
e4486fe3 SR |
56 | |
57 | /* read the text we want to modify */ | |
b54dcfe1 | 58 | if (probe_kernel_read(&replaced, (void *)ip, MCOUNT_INSN_SIZE)) |
e4486fe3 SR |
59 | return -EFAULT; |
60 | ||
61 | /* Make sure it is what we expect it to be */ | |
b54dcfe1 | 62 | if (replaced != old) |
e4486fe3 SR |
63 | return -EINVAL; |
64 | ||
65 | /* replace the text with the new text */ | |
65b8c722 | 66 | if (patch_instruction((unsigned int *)ip, new)) |
e4486fe3 SR |
67 | return -EPERM; |
68 | ||
e4486fe3 | 69 | return 0; |
4e491d14 SR |
70 | } |
71 | ||
f48cb8b4 SR |
72 | /* |
73 | * Helper functions that are the same for both PPC64 and PPC32. | |
74 | */ | |
8fd6e5a8 SR |
75 | static int test_24bit_addr(unsigned long ip, unsigned long addr) |
76 | { | |
8fd6e5a8 | 77 | |
0029ff87 SR |
78 | /* use the create_branch to verify that this offset can be branched */ |
79 | return create_branch((unsigned int *)ip, addr, 0); | |
8fd6e5a8 SR |
80 | } |
81 | ||
17be5b3d SR |
82 | #ifdef CONFIG_MODULES |
83 | ||
f48cb8b4 SR |
84 | static int is_bl_op(unsigned int op) |
85 | { | |
86 | return (op & 0xfc000003) == 0x48000001; | |
87 | } | |
88 | ||
f48cb8b4 SR |
89 | static unsigned long find_bl_target(unsigned long ip, unsigned int op) |
90 | { | |
91 | static int offset; | |
92 | ||
93 | offset = (op & 0x03fffffc); | |
94 | /* make it signed */ | |
95 | if (offset & 0x02000000) | |
96 | offset |= 0xfe000000; | |
97 | ||
98 | return ip + (long)offset; | |
99 | } | |
100 | ||
f48cb8b4 SR |
101 | #ifdef CONFIG_PPC64 |
102 | static int | |
103 | __ftrace_make_nop(struct module *mod, | |
104 | struct dyn_ftrace *rec, unsigned long addr) | |
105 | { | |
d9af12b7 SR |
106 | unsigned int op; |
107 | unsigned int jmp[5]; | |
108 | unsigned long ptr; | |
f48cb8b4 SR |
109 | unsigned long ip = rec->ip; |
110 | unsigned long tramp; | |
111 | int offset; | |
112 | ||
113 | /* read where this goes */ | |
d9af12b7 | 114 | if (probe_kernel_read(&op, (void *)ip, sizeof(int))) |
f48cb8b4 SR |
115 | return -EFAULT; |
116 | ||
117 | /* Make sure that that this is still a 24bit jump */ | |
d9af12b7 SR |
118 | if (!is_bl_op(op)) { |
119 | printk(KERN_ERR "Not expected bl: opcode is %x\n", op); | |
f48cb8b4 SR |
120 | return -EINVAL; |
121 | } | |
122 | ||
123 | /* lets find where the pointer goes */ | |
d9af12b7 | 124 | tramp = find_bl_target(ip, op); |
f48cb8b4 SR |
125 | |
126 | /* | |
127 | * On PPC64 the trampoline looks like: | |
128 | * 0x3d, 0x82, 0x00, 0x00, addis r12,r2, <high> | |
129 | * 0x39, 0x8c, 0x00, 0x00, addi r12,r12, <low> | |
130 | * Where the bytes 2,3,6 and 7 make up the 32bit offset | |
131 | * to the TOC that holds the pointer. | |
132 | * to jump to. | |
133 | * 0xf8, 0x41, 0x00, 0x28, std r2,40(r1) | |
134 | * 0xe9, 0x6c, 0x00, 0x20, ld r11,32(r12) | |
135 | * The actually address is 32 bytes from the offset | |
136 | * into the TOC. | |
137 | * 0xe8, 0x4c, 0x00, 0x28, ld r2,40(r12) | |
138 | */ | |
139 | ||
021376a3 | 140 | pr_devel("ip:%lx jumps to %lx r2: %lx", ip, tramp, mod->arch.toc); |
f48cb8b4 SR |
141 | |
142 | /* Find where the trampoline jumps to */ | |
d9af12b7 | 143 | if (probe_kernel_read(jmp, (void *)tramp, sizeof(jmp))) { |
f48cb8b4 SR |
144 | printk(KERN_ERR "Failed to read %lx\n", tramp); |
145 | return -EFAULT; | |
146 | } | |
147 | ||
021376a3 | 148 | pr_devel(" %08x %08x", jmp[0], jmp[1]); |
d9af12b7 SR |
149 | |
150 | /* verify that this is what we expect it to be */ | |
151 | if (((jmp[0] & 0xffff0000) != 0x3d820000) || | |
152 | ((jmp[1] & 0xffff0000) != 0x398c0000) || | |
153 | (jmp[2] != 0xf8410028) || | |
154 | (jmp[3] != 0xe96c0020) || | |
155 | (jmp[4] != 0xe84c0028)) { | |
156 | printk(KERN_ERR "Not a trampoline\n"); | |
157 | return -EINVAL; | |
158 | } | |
f48cb8b4 | 159 | |
f25f9074 SR |
160 | /* The bottom half is signed extended */ |
161 | offset = ((unsigned)((unsigned short)jmp[0]) << 16) + | |
162 | (int)((short)jmp[1]); | |
f48cb8b4 | 163 | |
021376a3 | 164 | pr_devel(" %x ", offset); |
f48cb8b4 SR |
165 | |
166 | /* get the address this jumps too */ | |
167 | tramp = mod->arch.toc + offset + 32; | |
021376a3 | 168 | pr_devel("toc: %lx", tramp); |
f48cb8b4 SR |
169 | |
170 | if (probe_kernel_read(jmp, (void *)tramp, 8)) { | |
171 | printk(KERN_ERR "Failed to read %lx\n", tramp); | |
172 | return -EFAULT; | |
173 | } | |
174 | ||
021376a3 | 175 | pr_devel(" %08x %08x\n", jmp[0], jmp[1]); |
d9af12b7 | 176 | |
30647430 ES |
177 | #ifdef __LITTLE_ENDIAN__ |
178 | ptr = ((unsigned long)jmp[1] << 32) + jmp[0]; | |
179 | #else | |
d9af12b7 | 180 | ptr = ((unsigned long)jmp[0] << 32) + jmp[1]; |
30647430 | 181 | #endif |
f48cb8b4 SR |
182 | |
183 | /* This should match what was called */ | |
4a9e3f8e | 184 | if (ptr != ppc_function_entry((void *)addr)) { |
d9af12b7 | 185 | printk(KERN_ERR "addr does not match %lx\n", ptr); |
f48cb8b4 SR |
186 | return -EINVAL; |
187 | } | |
188 | ||
189 | /* | |
190 | * We want to nop the line, but the next line is | |
191 | * 0xe8, 0x41, 0x00, 0x28 ld r2,40(r1) | |
192 | * This needs to be turned to a nop too. | |
193 | */ | |
d9af12b7 | 194 | if (probe_kernel_read(&op, (void *)(ip+4), MCOUNT_INSN_SIZE)) |
f48cb8b4 SR |
195 | return -EFAULT; |
196 | ||
d9af12b7 SR |
197 | if (op != 0xe8410028) { |
198 | printk(KERN_ERR "Next line is not ld! (%08x)\n", op); | |
f48cb8b4 SR |
199 | return -EINVAL; |
200 | } | |
201 | ||
202 | /* | |
203 | * Milton Miller pointed out that we can not blindly do nops. | |
204 | * If a task was preempted when calling a trace function, | |
205 | * the nops will remove the way to restore the TOC in r2 | |
206 | * and the r2 TOC will get corrupted. | |
207 | */ | |
208 | ||
209 | /* | |
210 | * Replace: | |
211 | * bl <tramp> <==== will be replaced with "b 1f" | |
212 | * ld r2,40(r1) | |
213 | * 1: | |
214 | */ | |
d9af12b7 | 215 | op = 0x48000008; /* b +8 */ |
f48cb8b4 | 216 | |
65b8c722 | 217 | if (patch_instruction((unsigned int *)ip, op)) |
f48cb8b4 SR |
218 | return -EPERM; |
219 | ||
220 | return 0; | |
221 | } | |
222 | ||
223 | #else /* !PPC64 */ | |
224 | static int | |
225 | __ftrace_make_nop(struct module *mod, | |
226 | struct dyn_ftrace *rec, unsigned long addr) | |
227 | { | |
d9af12b7 SR |
228 | unsigned int op; |
229 | unsigned int jmp[4]; | |
7cc45e64 SR |
230 | unsigned long ip = rec->ip; |
231 | unsigned long tramp; | |
7cc45e64 | 232 | |
d9af12b7 | 233 | if (probe_kernel_read(&op, (void *)ip, MCOUNT_INSN_SIZE)) |
7cc45e64 SR |
234 | return -EFAULT; |
235 | ||
236 | /* Make sure that that this is still a 24bit jump */ | |
d9af12b7 SR |
237 | if (!is_bl_op(op)) { |
238 | printk(KERN_ERR "Not expected bl: opcode is %x\n", op); | |
7cc45e64 SR |
239 | return -EINVAL; |
240 | } | |
241 | ||
242 | /* lets find where the pointer goes */ | |
d9af12b7 | 243 | tramp = find_bl_target(ip, op); |
7cc45e64 SR |
244 | |
245 | /* | |
246 | * On PPC32 the trampoline looks like: | |
fd5a4298 | 247 | * 0x3d, 0x80, 0x00, 0x00 lis r12,sym@ha |
248 | * 0x39, 0x8c, 0x00, 0x00 addi r12,r12,sym@l | |
249 | * 0x7d, 0x89, 0x03, 0xa6 mtctr r12 | |
d9af12b7 | 250 | * 0x4e, 0x80, 0x04, 0x20 bctr |
7cc45e64 SR |
251 | */ |
252 | ||
021376a3 | 253 | pr_devel("ip:%lx jumps to %lx", ip, tramp); |
7cc45e64 SR |
254 | |
255 | /* Find where the trampoline jumps to */ | |
d9af12b7 | 256 | if (probe_kernel_read(jmp, (void *)tramp, sizeof(jmp))) { |
7cc45e64 SR |
257 | printk(KERN_ERR "Failed to read %lx\n", tramp); |
258 | return -EFAULT; | |
259 | } | |
260 | ||
021376a3 | 261 | pr_devel(" %08x %08x ", jmp[0], jmp[1]); |
d9af12b7 SR |
262 | |
263 | /* verify that this is what we expect it to be */ | |
fd5a4298 | 264 | if (((jmp[0] & 0xffff0000) != 0x3d800000) || |
265 | ((jmp[1] & 0xffff0000) != 0x398c0000) || | |
266 | (jmp[2] != 0x7d8903a6) || | |
d9af12b7 SR |
267 | (jmp[3] != 0x4e800420)) { |
268 | printk(KERN_ERR "Not a trampoline\n"); | |
269 | return -EINVAL; | |
270 | } | |
7cc45e64 | 271 | |
d9af12b7 SR |
272 | tramp = (jmp[1] & 0xffff) | |
273 | ((jmp[0] & 0xffff) << 16); | |
7cc45e64 SR |
274 | if (tramp & 0x8000) |
275 | tramp -= 0x10000; | |
276 | ||
021376a3 | 277 | pr_devel(" %lx ", tramp); |
7cc45e64 SR |
278 | |
279 | if (tramp != addr) { | |
280 | printk(KERN_ERR | |
281 | "Trampoline location %08lx does not match addr\n", | |
282 | tramp); | |
283 | return -EINVAL; | |
284 | } | |
285 | ||
16c57b36 | 286 | op = PPC_INST_NOP; |
7cc45e64 | 287 | |
65b8c722 | 288 | if (patch_instruction((unsigned int *)ip, op)) |
7cc45e64 SR |
289 | return -EPERM; |
290 | ||
f48cb8b4 SR |
291 | return 0; |
292 | } | |
293 | #endif /* PPC64 */ | |
17be5b3d | 294 | #endif /* CONFIG_MODULES */ |
f48cb8b4 | 295 | |
8fd6e5a8 SR |
296 | int ftrace_make_nop(struct module *mod, |
297 | struct dyn_ftrace *rec, unsigned long addr) | |
298 | { | |
f48cb8b4 | 299 | unsigned long ip = rec->ip; |
b54dcfe1 | 300 | unsigned int old, new; |
8fd6e5a8 SR |
301 | |
302 | /* | |
303 | * If the calling address is more that 24 bits away, | |
304 | * then we had to use a trampoline to make the call. | |
305 | * Otherwise just update the call site. | |
306 | */ | |
f48cb8b4 | 307 | if (test_24bit_addr(ip, addr)) { |
8fd6e5a8 | 308 | /* within range */ |
46542888 | 309 | old = ftrace_call_replace(ip, addr, 1); |
92e02a51 | 310 | new = PPC_INST_NOP; |
f48cb8b4 SR |
311 | return ftrace_modify_code(ip, old, new); |
312 | } | |
313 | ||
17be5b3d | 314 | #ifdef CONFIG_MODULES |
f48cb8b4 SR |
315 | /* |
316 | * Out of range jumps are called from modules. | |
317 | * We should either already have a pointer to the module | |
318 | * or it has been passed in. | |
319 | */ | |
320 | if (!rec->arch.mod) { | |
321 | if (!mod) { | |
322 | printk(KERN_ERR "No module loaded addr=%lx\n", | |
323 | addr); | |
324 | return -EFAULT; | |
325 | } | |
326 | rec->arch.mod = mod; | |
327 | } else if (mod) { | |
328 | if (mod != rec->arch.mod) { | |
329 | printk(KERN_ERR | |
330 | "Record mod %p not equal to passed in mod %p\n", | |
331 | rec->arch.mod, mod); | |
332 | return -EINVAL; | |
333 | } | |
334 | /* nothing to do if mod == rec->arch.mod */ | |
335 | } else | |
336 | mod = rec->arch.mod; | |
f48cb8b4 SR |
337 | |
338 | return __ftrace_make_nop(mod, rec, addr); | |
17be5b3d SR |
339 | #else |
340 | /* We should not get here without modules */ | |
341 | return -EINVAL; | |
342 | #endif /* CONFIG_MODULES */ | |
f48cb8b4 SR |
343 | } |
344 | ||
17be5b3d | 345 | #ifdef CONFIG_MODULES |
f48cb8b4 SR |
346 | #ifdef CONFIG_PPC64 |
347 | static int | |
348 | __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) | |
349 | { | |
d9af12b7 | 350 | unsigned int op[2]; |
f48cb8b4 | 351 | unsigned long ip = rec->ip; |
f48cb8b4 SR |
352 | |
353 | /* read where this goes */ | |
d9af12b7 | 354 | if (probe_kernel_read(op, (void *)ip, MCOUNT_INSN_SIZE * 2)) |
f48cb8b4 SR |
355 | return -EFAULT; |
356 | ||
357 | /* | |
358 | * It should be pointing to two nops or | |
359 | * b +8; ld r2,40(r1) | |
360 | */ | |
361 | if (((op[0] != 0x48000008) || (op[1] != 0xe8410028)) && | |
16c57b36 | 362 | ((op[0] != PPC_INST_NOP) || (op[1] != PPC_INST_NOP))) { |
f48cb8b4 SR |
363 | printk(KERN_ERR "Expected NOPs but have %x %x\n", op[0], op[1]); |
364 | return -EINVAL; | |
365 | } | |
366 | ||
367 | /* If we never set up a trampoline to ftrace_caller, then bail */ | |
368 | if (!rec->arch.mod->arch.tramp) { | |
369 | printk(KERN_ERR "No ftrace trampoline\n"); | |
370 | return -EINVAL; | |
371 | } | |
372 | ||
0029ff87 SR |
373 | /* create the branch to the trampoline */ |
374 | op[0] = create_branch((unsigned int *)ip, | |
375 | rec->arch.mod->arch.tramp, BRANCH_SET_LINK); | |
376 | if (!op[0]) { | |
377 | printk(KERN_ERR "REL24 out of range!\n"); | |
f48cb8b4 | 378 | return -EINVAL; |
8fd6e5a8 SR |
379 | } |
380 | ||
f48cb8b4 SR |
381 | /* ld r2,40(r1) */ |
382 | op[1] = 0xe8410028; | |
383 | ||
021376a3 | 384 | pr_devel("write to %lx\n", rec->ip); |
f48cb8b4 | 385 | |
d9af12b7 | 386 | if (probe_kernel_write((void *)ip, op, MCOUNT_INSN_SIZE * 2)) |
f48cb8b4 SR |
387 | return -EPERM; |
388 | ||
ec682cef SR |
389 | flush_icache_range(ip, ip + 8); |
390 | ||
8fd6e5a8 SR |
391 | return 0; |
392 | } | |
f48cb8b4 SR |
393 | #else |
394 | static int | |
395 | __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) | |
396 | { | |
d9af12b7 | 397 | unsigned int op; |
7cc45e64 | 398 | unsigned long ip = rec->ip; |
7cc45e64 SR |
399 | |
400 | /* read where this goes */ | |
d9af12b7 | 401 | if (probe_kernel_read(&op, (void *)ip, MCOUNT_INSN_SIZE)) |
7cc45e64 SR |
402 | return -EFAULT; |
403 | ||
404 | /* It should be pointing to a nop */ | |
16c57b36 | 405 | if (op != PPC_INST_NOP) { |
d9af12b7 | 406 | printk(KERN_ERR "Expected NOP but have %x\n", op); |
7cc45e64 SR |
407 | return -EINVAL; |
408 | } | |
409 | ||
410 | /* If we never set up a trampoline to ftrace_caller, then bail */ | |
411 | if (!rec->arch.mod->arch.tramp) { | |
412 | printk(KERN_ERR "No ftrace trampoline\n"); | |
413 | return -EINVAL; | |
414 | } | |
415 | ||
0029ff87 SR |
416 | /* create the branch to the trampoline */ |
417 | op = create_branch((unsigned int *)ip, | |
418 | rec->arch.mod->arch.tramp, BRANCH_SET_LINK); | |
419 | if (!op) { | |
420 | printk(KERN_ERR "REL24 out of range!\n"); | |
7cc45e64 SR |
421 | return -EINVAL; |
422 | } | |
423 | ||
021376a3 | 424 | pr_devel("write to %lx\n", rec->ip); |
7cc45e64 | 425 | |
65b8c722 | 426 | if (patch_instruction((unsigned int *)ip, op)) |
7cc45e64 SR |
427 | return -EPERM; |
428 | ||
f48cb8b4 SR |
429 | return 0; |
430 | } | |
431 | #endif /* CONFIG_PPC64 */ | |
17be5b3d | 432 | #endif /* CONFIG_MODULES */ |
8fd6e5a8 SR |
433 | |
434 | int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) | |
435 | { | |
f48cb8b4 | 436 | unsigned long ip = rec->ip; |
b54dcfe1 | 437 | unsigned int old, new; |
8fd6e5a8 SR |
438 | |
439 | /* | |
440 | * If the calling address is more that 24 bits away, | |
441 | * then we had to use a trampoline to make the call. | |
442 | * Otherwise just update the call site. | |
443 | */ | |
f48cb8b4 | 444 | if (test_24bit_addr(ip, addr)) { |
8fd6e5a8 | 445 | /* within range */ |
92e02a51 | 446 | old = PPC_INST_NOP; |
46542888 | 447 | new = ftrace_call_replace(ip, addr, 1); |
f48cb8b4 | 448 | return ftrace_modify_code(ip, old, new); |
8fd6e5a8 SR |
449 | } |
450 | ||
17be5b3d | 451 | #ifdef CONFIG_MODULES |
f48cb8b4 SR |
452 | /* |
453 | * Out of range jumps are called from modules. | |
454 | * Being that we are converting from nop, it had better | |
455 | * already have a module defined. | |
456 | */ | |
457 | if (!rec->arch.mod) { | |
458 | printk(KERN_ERR "No module loaded\n"); | |
459 | return -EINVAL; | |
460 | } | |
f48cb8b4 SR |
461 | |
462 | return __ftrace_make_call(rec, addr); | |
17be5b3d SR |
463 | #else |
464 | /* We should not get here without modules */ | |
465 | return -EINVAL; | |
466 | #endif /* CONFIG_MODULES */ | |
8fd6e5a8 SR |
467 | } |
468 | ||
15adc048 | 469 | int ftrace_update_ftrace_func(ftrace_func_t func) |
4e491d14 SR |
470 | { |
471 | unsigned long ip = (unsigned long)(&ftrace_call); | |
b54dcfe1 | 472 | unsigned int old, new; |
4e491d14 SR |
473 | int ret; |
474 | ||
b54dcfe1 | 475 | old = *(unsigned int *)&ftrace_call; |
46542888 | 476 | new = ftrace_call_replace(ip, (unsigned long)func, 1); |
4e491d14 SR |
477 | ret = ftrace_modify_code(ip, old, new); |
478 | ||
479 | return ret; | |
480 | } | |
481 | ||
ee456bb3 SR |
482 | static int __ftrace_replace_code(struct dyn_ftrace *rec, int enable) |
483 | { | |
484 | unsigned long ftrace_addr = (unsigned long)FTRACE_ADDR; | |
485 | int ret; | |
486 | ||
487 | ret = ftrace_update_record(rec, enable); | |
488 | ||
489 | switch (ret) { | |
490 | case FTRACE_UPDATE_IGNORE: | |
491 | return 0; | |
492 | case FTRACE_UPDATE_MAKE_CALL: | |
493 | return ftrace_make_call(rec, ftrace_addr); | |
494 | case FTRACE_UPDATE_MAKE_NOP: | |
495 | return ftrace_make_nop(NULL, rec, ftrace_addr); | |
496 | } | |
497 | ||
498 | return 0; | |
499 | } | |
500 | ||
501 | void ftrace_replace_code(int enable) | |
502 | { | |
503 | struct ftrace_rec_iter *iter; | |
504 | struct dyn_ftrace *rec; | |
505 | int ret; | |
506 | ||
507 | for (iter = ftrace_rec_iter_start(); iter; | |
508 | iter = ftrace_rec_iter_next(iter)) { | |
509 | rec = ftrace_rec_iter_record(iter); | |
510 | ret = __ftrace_replace_code(rec, enable); | |
511 | if (ret) { | |
512 | ftrace_bug(ret, rec->ip); | |
513 | return; | |
514 | } | |
515 | } | |
516 | } | |
517 | ||
518 | void arch_ftrace_update_code(int command) | |
519 | { | |
520 | if (command & FTRACE_UPDATE_CALLS) | |
521 | ftrace_replace_code(1); | |
522 | else if (command & FTRACE_DISABLE_CALLS) | |
523 | ftrace_replace_code(0); | |
524 | ||
525 | if (command & FTRACE_UPDATE_TRACE_FUNC) | |
526 | ftrace_update_ftrace_func(ftrace_trace_function); | |
527 | ||
528 | if (command & FTRACE_START_FUNC_RET) | |
529 | ftrace_enable_ftrace_graph_caller(); | |
530 | else if (command & FTRACE_STOP_FUNC_RET) | |
531 | ftrace_disable_ftrace_graph_caller(); | |
532 | } | |
533 | ||
3a36cb11 | 534 | int __init ftrace_dyn_arch_init(void) |
4e491d14 | 535 | { |
4e491d14 SR |
536 | return 0; |
537 | } | |
6794c782 SR |
538 | #endif /* CONFIG_DYNAMIC_FTRACE */ |
539 | ||
540 | #ifdef CONFIG_FUNCTION_GRAPH_TRACER | |
541 | ||
46542888 SR |
542 | #ifdef CONFIG_DYNAMIC_FTRACE |
543 | extern void ftrace_graph_call(void); | |
544 | extern void ftrace_graph_stub(void); | |
545 | ||
546 | int ftrace_enable_ftrace_graph_caller(void) | |
547 | { | |
548 | unsigned long ip = (unsigned long)(&ftrace_graph_call); | |
549 | unsigned long addr = (unsigned long)(&ftrace_graph_caller); | |
550 | unsigned long stub = (unsigned long)(&ftrace_graph_stub); | |
b54dcfe1 | 551 | unsigned int old, new; |
46542888 | 552 | |
b54dcfe1 | 553 | old = ftrace_call_replace(ip, stub, 0); |
46542888 SR |
554 | new = ftrace_call_replace(ip, addr, 0); |
555 | ||
556 | return ftrace_modify_code(ip, old, new); | |
557 | } | |
558 | ||
559 | int ftrace_disable_ftrace_graph_caller(void) | |
560 | { | |
561 | unsigned long ip = (unsigned long)(&ftrace_graph_call); | |
562 | unsigned long addr = (unsigned long)(&ftrace_graph_caller); | |
563 | unsigned long stub = (unsigned long)(&ftrace_graph_stub); | |
b54dcfe1 | 564 | unsigned int old, new; |
46542888 | 565 | |
b54dcfe1 | 566 | old = ftrace_call_replace(ip, addr, 0); |
46542888 SR |
567 | new = ftrace_call_replace(ip, stub, 0); |
568 | ||
569 | return ftrace_modify_code(ip, old, new); | |
570 | } | |
571 | #endif /* CONFIG_DYNAMIC_FTRACE */ | |
572 | ||
bb725340 SR |
573 | #ifdef CONFIG_PPC64 |
574 | extern void mod_return_to_handler(void); | |
575 | #endif | |
576 | ||
6794c782 SR |
577 | /* |
578 | * Hook the return address and push it in the stack of return addrs | |
579 | * in current thread info. | |
580 | */ | |
581 | void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr) | |
582 | { | |
583 | unsigned long old; | |
6794c782 SR |
584 | int faulted; |
585 | struct ftrace_graph_ent trace; | |
bb725340 | 586 | unsigned long return_hooker = (unsigned long)&return_to_handler; |
6794c782 SR |
587 | |
588 | if (unlikely(atomic_read(¤t->tracing_graph_pause))) | |
589 | return; | |
590 | ||
f4952f6c | 591 | #ifdef CONFIG_PPC64 |
bb725340 SR |
592 | /* non core kernel code needs to save and restore the TOC */ |
593 | if (REGION_ID(self_addr) != KERNEL_REGION_ID) | |
594 | return_hooker = (unsigned long)&mod_return_to_handler; | |
595 | #endif | |
596 | ||
4a9e3f8e | 597 | return_hooker = ppc_function_entry((void *)return_hooker); |
6794c782 SR |
598 | |
599 | /* | |
600 | * Protect against fault, even if it shouldn't | |
601 | * happen. This tool is too much intrusive to | |
602 | * ignore such a protection. | |
603 | */ | |
604 | asm volatile( | |
605 | "1: " PPC_LL "%[old], 0(%[parent])\n" | |
606 | "2: " PPC_STL "%[return_hooker], 0(%[parent])\n" | |
607 | " li %[faulted], 0\n" | |
fad4f47c | 608 | "3:\n" |
6794c782 SR |
609 | |
610 | ".section .fixup, \"ax\"\n" | |
611 | "4: li %[faulted], 1\n" | |
612 | " b 3b\n" | |
613 | ".previous\n" | |
614 | ||
615 | ".section __ex_table,\"a\"\n" | |
616 | PPC_LONG_ALIGN "\n" | |
617 | PPC_LONG "1b,4b\n" | |
618 | PPC_LONG "2b,4b\n" | |
619 | ".previous" | |
620 | ||
c3cf8667 | 621 | : [old] "=&r" (old), [faulted] "=r" (faulted) |
6794c782 SR |
622 | : [parent] "r" (parent), [return_hooker] "r" (return_hooker) |
623 | : "memory" | |
624 | ); | |
625 | ||
626 | if (unlikely(faulted)) { | |
627 | ftrace_graph_stop(); | |
628 | WARN_ON(1); | |
629 | return; | |
630 | } | |
631 | ||
6794c782 | 632 | trace.func = self_addr; |
bac821a6 | 633 | trace.depth = current->curr_ret_stack + 1; |
6794c782 SR |
634 | |
635 | /* Only trace if the calling function expects to */ | |
636 | if (!ftrace_graph_entry(&trace)) { | |
6794c782 | 637 | *parent = old; |
bac821a6 | 638 | return; |
6794c782 | 639 | } |
bac821a6 SR |
640 | |
641 | if (ftrace_push_return_trace(old, self_addr, &trace.depth, 0) == -EBUSY) | |
642 | *parent = old; | |
6794c782 SR |
643 | } |
644 | #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ | |
02424d89 IM |
645 | |
646 | #if defined(CONFIG_FTRACE_SYSCALLS) && defined(CONFIG_PPC64) | |
647 | unsigned long __init arch_syscall_addr(int nr) | |
648 | { | |
649 | return sys_call_table[nr*2]; | |
650 | } | |
651 | #endif /* CONFIG_FTRACE_SYSCALLS && CONFIG_PPC64 */ |