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7f7797b3 NR |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Code for replacing ftrace calls with jumps. | |
4 | * | |
5 | * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> | |
6 | * | |
7 | * Thanks goes out to P.A. Semi, Inc for supplying me with a PPC64 box. | |
8 | * | |
9 | * Added function graph tracer code, taken from x86 that was written | |
10 | * by Frederic Weisbecker, and ported to PPC by Steven Rostedt. | |
11 | * | |
12 | */ | |
13 | ||
14 | #define pr_fmt(fmt) "ftrace-powerpc: " fmt | |
15 | ||
16 | #include <linux/spinlock.h> | |
17 | #include <linux/hardirq.h> | |
18 | #include <linux/uaccess.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/ftrace.h> | |
21 | #include <linux/percpu.h> | |
22 | #include <linux/init.h> | |
23 | #include <linux/list.h> | |
24 | ||
25 | #include <asm/cacheflush.h> | |
26 | #include <asm/code-patching.h> | |
27 | #include <asm/ftrace.h> | |
28 | #include <asm/syscall.h> | |
29 | #include <asm/inst.h> | |
30 | ||
31 | /* | |
32 | * We generally only have a single long_branch tramp and at most 2 or 3 plt | |
33 | * tramps generated. But, we don't use the plt tramps currently. We also allot | |
34 | * 2 tramps after .text and .init.text. So, we only end up with around 3 usable | |
35 | * tramps in total. Set aside 8 just to be sure. | |
36 | */ | |
37 | #define NUM_FTRACE_TRAMPS 8 | |
38 | static unsigned long ftrace_tramps[NUM_FTRACE_TRAMPS]; | |
39 | ||
ea73179e NR |
40 | unsigned long ftrace_call_adjust(unsigned long addr) |
41 | { | |
42 | return addr; | |
43 | } | |
44 | ||
7f7797b3 NR |
45 | static ppc_inst_t |
46 | ftrace_call_replace(unsigned long ip, unsigned long addr, int link) | |
47 | { | |
48 | ppc_inst_t op; | |
49 | ||
50 | addr = ppc_function_entry((void *)addr); | |
51 | ||
52 | /* if (link) set op to 'bl' else 'b' */ | |
53 | create_branch(&op, (u32 *)ip, addr, link ? BRANCH_SET_LINK : 0); | |
54 | ||
55 | return op; | |
56 | } | |
57 | ||
58 | static inline int | |
59 | ftrace_modify_code(unsigned long ip, ppc_inst_t old, ppc_inst_t new) | |
60 | { | |
61 | ppc_inst_t replaced; | |
62 | ||
63 | /* | |
64 | * Note: | |
65 | * We are paranoid about modifying text, as if a bug was to happen, it | |
66 | * could cause us to read or write to someplace that could cause harm. | |
67 | * Carefully read and modify the code with probe_kernel_*(), and make | |
68 | * sure what we read is what we expected it to be before modifying it. | |
69 | */ | |
70 | ||
71 | /* read the text we want to modify */ | |
72 | if (copy_inst_from_kernel_nofault(&replaced, (void *)ip)) | |
73 | return -EFAULT; | |
74 | ||
75 | /* Make sure it is what we expect it to be */ | |
76 | if (!ppc_inst_equal(replaced, old)) { | |
77 | pr_err("%p: replaced (%08lx) != old (%08lx)", (void *)ip, | |
78 | ppc_inst_as_ulong(replaced), ppc_inst_as_ulong(old)); | |
79 | return -EINVAL; | |
80 | } | |
81 | ||
82 | /* replace the text with the new text */ | |
83 | return patch_instruction((u32 *)ip, new); | |
84 | } | |
85 | ||
86 | /* | |
87 | * Helper functions that are the same for both PPC64 and PPC32. | |
88 | */ | |
89 | static int test_24bit_addr(unsigned long ip, unsigned long addr) | |
90 | { | |
91 | addr = ppc_function_entry((void *)addr); | |
92 | ||
93 | return is_offset_in_branch_range(addr - ip); | |
94 | } | |
95 | ||
96 | static int is_bl_op(ppc_inst_t op) | |
97 | { | |
98 | return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BL(0); | |
99 | } | |
100 | ||
101 | static int is_b_op(ppc_inst_t op) | |
102 | { | |
103 | return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BRANCH(0); | |
104 | } | |
105 | ||
106 | static unsigned long find_bl_target(unsigned long ip, ppc_inst_t op) | |
107 | { | |
108 | int offset; | |
109 | ||
110 | offset = PPC_LI(ppc_inst_val(op)); | |
111 | /* make it signed */ | |
112 | if (offset & 0x02000000) | |
113 | offset |= 0xfe000000; | |
114 | ||
115 | return ip + (long)offset; | |
116 | } | |
117 | ||
118 | #ifdef CONFIG_MODULES | |
119 | static int | |
120 | __ftrace_make_nop(struct module *mod, | |
121 | struct dyn_ftrace *rec, unsigned long addr) | |
122 | { | |
123 | unsigned long entry, ptr, tramp; | |
124 | unsigned long ip = rec->ip; | |
125 | ppc_inst_t op, pop; | |
126 | ||
127 | /* read where this goes */ | |
128 | if (copy_inst_from_kernel_nofault(&op, (void *)ip)) { | |
129 | pr_err("Fetching opcode failed.\n"); | |
130 | return -EFAULT; | |
131 | } | |
132 | ||
133 | /* Make sure that this is still a 24bit jump */ | |
134 | if (!is_bl_op(op)) { | |
135 | pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(op)); | |
136 | return -EINVAL; | |
137 | } | |
138 | ||
139 | /* lets find where the pointer goes */ | |
140 | tramp = find_bl_target(ip, op); | |
141 | ||
142 | pr_devel("ip:%lx jumps to %lx", ip, tramp); | |
143 | ||
144 | if (module_trampoline_target(mod, tramp, &ptr)) { | |
145 | pr_err("Failed to get trampoline target\n"); | |
146 | return -EFAULT; | |
147 | } | |
148 | ||
149 | pr_devel("trampoline target %lx", ptr); | |
150 | ||
151 | entry = ppc_global_function_entry((void *)addr); | |
152 | /* This should match what was called */ | |
153 | if (ptr != entry) { | |
154 | pr_err("addr %lx does not match expected %lx\n", ptr, entry); | |
155 | return -EINVAL; | |
156 | } | |
157 | ||
158 | if (IS_ENABLED(CONFIG_MPROFILE_KERNEL)) { | |
159 | if (copy_inst_from_kernel_nofault(&op, (void *)(ip - 4))) { | |
160 | pr_err("Fetching instruction at %lx failed.\n", ip - 4); | |
161 | return -EFAULT; | |
162 | } | |
163 | ||
164 | /* We expect either a mflr r0, or a std r0, LRSAVE(r1) */ | |
165 | if (!ppc_inst_equal(op, ppc_inst(PPC_RAW_MFLR(_R0))) && | |
166 | !ppc_inst_equal(op, ppc_inst(PPC_INST_STD_LR))) { | |
167 | pr_err("Unexpected instruction %08lx around bl _mcount\n", | |
168 | ppc_inst_as_ulong(op)); | |
169 | return -EINVAL; | |
170 | } | |
171 | } else if (IS_ENABLED(CONFIG_PPC64)) { | |
172 | /* | |
173 | * Check what is in the next instruction. We can see ld r2,40(r1), but | |
174 | * on first pass after boot we will see mflr r0. | |
175 | */ | |
176 | if (copy_inst_from_kernel_nofault(&op, (void *)(ip + 4))) { | |
177 | pr_err("Fetching op failed.\n"); | |
178 | return -EFAULT; | |
179 | } | |
180 | ||
181 | if (!ppc_inst_equal(op, ppc_inst(PPC_INST_LD_TOC))) { | |
182 | pr_err("Expected %08lx found %08lx\n", PPC_INST_LD_TOC, | |
183 | ppc_inst_as_ulong(op)); | |
184 | return -EINVAL; | |
185 | } | |
186 | } | |
187 | ||
188 | /* | |
189 | * When using -mprofile-kernel or PPC32 there is no load to jump over. | |
190 | * | |
191 | * Otherwise our original call site looks like: | |
192 | * | |
193 | * bl <tramp> | |
194 | * ld r2,XX(r1) | |
195 | * | |
196 | * Milton Miller pointed out that we can not simply nop the branch. | |
197 | * If a task was preempted when calling a trace function, the nops | |
198 | * will remove the way to restore the TOC in r2 and the r2 TOC will | |
199 | * get corrupted. | |
200 | * | |
201 | * Use a b +8 to jump over the load. | |
202 | */ | |
203 | if (IS_ENABLED(CONFIG_MPROFILE_KERNEL) || IS_ENABLED(CONFIG_PPC32)) | |
204 | pop = ppc_inst(PPC_RAW_NOP()); | |
205 | else | |
206 | pop = ppc_inst(PPC_RAW_BRANCH(8)); /* b +8 */ | |
207 | ||
208 | if (patch_instruction((u32 *)ip, pop)) { | |
209 | pr_err("Patching NOP failed.\n"); | |
210 | return -EPERM; | |
211 | } | |
212 | ||
213 | return 0; | |
214 | } | |
215 | #else | |
216 | static int __ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) | |
217 | { | |
218 | return 0; | |
219 | } | |
220 | #endif /* CONFIG_MODULES */ | |
221 | ||
222 | static unsigned long find_ftrace_tramp(unsigned long ip) | |
223 | { | |
224 | int i; | |
225 | ||
226 | /* | |
227 | * We have the compiler generated long_branch tramps at the end | |
228 | * and we prefer those | |
229 | */ | |
230 | for (i = NUM_FTRACE_TRAMPS - 1; i >= 0; i--) | |
231 | if (!ftrace_tramps[i]) | |
232 | continue; | |
233 | else if (is_offset_in_branch_range(ftrace_tramps[i] - ip)) | |
234 | return ftrace_tramps[i]; | |
235 | ||
236 | return 0; | |
237 | } | |
238 | ||
239 | static int add_ftrace_tramp(unsigned long tramp) | |
240 | { | |
241 | int i; | |
242 | ||
243 | for (i = 0; i < NUM_FTRACE_TRAMPS; i++) | |
244 | if (!ftrace_tramps[i]) { | |
245 | ftrace_tramps[i] = tramp; | |
246 | return 0; | |
247 | } | |
248 | ||
249 | return -1; | |
250 | } | |
251 | ||
252 | /* | |
253 | * If this is a compiler generated long_branch trampoline (essentially, a | |
254 | * trampoline that has a branch to _mcount()), we re-write the branch to | |
255 | * instead go to ftrace_[regs_]caller() and note down the location of this | |
256 | * trampoline. | |
257 | */ | |
258 | static int setup_mcount_compiler_tramp(unsigned long tramp) | |
259 | { | |
260 | int i; | |
261 | ppc_inst_t op; | |
262 | unsigned long ptr; | |
263 | ||
264 | /* Is this a known long jump tramp? */ | |
265 | for (i = 0; i < NUM_FTRACE_TRAMPS; i++) | |
266 | if (ftrace_tramps[i] == tramp) | |
267 | return 0; | |
268 | ||
269 | /* New trampoline -- read where this goes */ | |
270 | if (copy_inst_from_kernel_nofault(&op, (void *)tramp)) { | |
271 | pr_debug("Fetching opcode failed.\n"); | |
272 | return -1; | |
273 | } | |
274 | ||
275 | /* Is this a 24 bit branch? */ | |
276 | if (!is_b_op(op)) { | |
277 | pr_debug("Trampoline is not a long branch tramp.\n"); | |
278 | return -1; | |
279 | } | |
280 | ||
281 | /* lets find where the pointer goes */ | |
282 | ptr = find_bl_target(tramp, op); | |
283 | ||
284 | if (ptr != ppc_global_function_entry((void *)_mcount)) { | |
285 | pr_debug("Trampoline target %p is not _mcount\n", (void *)ptr); | |
286 | return -1; | |
287 | } | |
288 | ||
289 | /* Let's re-write the tramp to go to ftrace_[regs_]caller */ | |
290 | if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) | |
291 | ptr = ppc_global_function_entry((void *)ftrace_regs_caller); | |
292 | else | |
293 | ptr = ppc_global_function_entry((void *)ftrace_caller); | |
294 | ||
295 | if (patch_branch((u32 *)tramp, ptr, 0)) { | |
296 | pr_debug("REL24 out of range!\n"); | |
297 | return -1; | |
298 | } | |
299 | ||
300 | if (add_ftrace_tramp(tramp)) { | |
301 | pr_debug("No tramp locations left\n"); | |
302 | return -1; | |
303 | } | |
304 | ||
305 | return 0; | |
306 | } | |
307 | ||
308 | static int __ftrace_make_nop_kernel(struct dyn_ftrace *rec, unsigned long addr) | |
309 | { | |
310 | unsigned long tramp, ip = rec->ip; | |
311 | ppc_inst_t op; | |
312 | ||
313 | /* Read where this goes */ | |
314 | if (copy_inst_from_kernel_nofault(&op, (void *)ip)) { | |
315 | pr_err("Fetching opcode failed.\n"); | |
316 | return -EFAULT; | |
317 | } | |
318 | ||
319 | /* Make sure that this is still a 24bit jump */ | |
320 | if (!is_bl_op(op)) { | |
321 | pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(op)); | |
322 | return -EINVAL; | |
323 | } | |
324 | ||
325 | /* Let's find where the pointer goes */ | |
326 | tramp = find_bl_target(ip, op); | |
327 | ||
328 | pr_devel("ip:%lx jumps to %lx", ip, tramp); | |
329 | ||
330 | if (setup_mcount_compiler_tramp(tramp)) { | |
331 | /* Are other trampolines reachable? */ | |
332 | if (!find_ftrace_tramp(ip)) { | |
333 | pr_err("No ftrace trampolines reachable from %ps\n", | |
334 | (void *)ip); | |
335 | return -EINVAL; | |
336 | } | |
337 | } | |
338 | ||
339 | if (patch_instruction((u32 *)ip, ppc_inst(PPC_RAW_NOP()))) { | |
340 | pr_err("Patching NOP failed.\n"); | |
341 | return -EPERM; | |
342 | } | |
343 | ||
344 | return 0; | |
345 | } | |
346 | ||
347 | int ftrace_make_nop(struct module *mod, | |
348 | struct dyn_ftrace *rec, unsigned long addr) | |
349 | { | |
350 | unsigned long ip = rec->ip; | |
351 | ppc_inst_t old, new; | |
352 | ||
353 | /* | |
354 | * If the calling address is more that 24 bits away, | |
355 | * then we had to use a trampoline to make the call. | |
356 | * Otherwise just update the call site. | |
357 | */ | |
358 | if (test_24bit_addr(ip, addr)) { | |
359 | /* within range */ | |
360 | old = ftrace_call_replace(ip, addr, 1); | |
361 | new = ppc_inst(PPC_RAW_NOP()); | |
362 | return ftrace_modify_code(ip, old, new); | |
363 | } else if (core_kernel_text(ip)) { | |
364 | return __ftrace_make_nop_kernel(rec, addr); | |
365 | } else if (!IS_ENABLED(CONFIG_MODULES)) { | |
366 | return -EINVAL; | |
367 | } | |
368 | ||
369 | /* | |
370 | * Out of range jumps are called from modules. | |
371 | * We should either already have a pointer to the module | |
372 | * or it has been passed in. | |
373 | */ | |
374 | if (!rec->arch.mod) { | |
375 | if (!mod) { | |
376 | pr_err("No module loaded addr=%lx\n", addr); | |
377 | return -EFAULT; | |
378 | } | |
379 | rec->arch.mod = mod; | |
380 | } else if (mod) { | |
381 | if (mod != rec->arch.mod) { | |
382 | pr_err("Record mod %p not equal to passed in mod %p\n", | |
383 | rec->arch.mod, mod); | |
384 | return -EINVAL; | |
385 | } | |
386 | /* nothing to do if mod == rec->arch.mod */ | |
387 | } else | |
388 | mod = rec->arch.mod; | |
389 | ||
390 | return __ftrace_make_nop(mod, rec, addr); | |
391 | } | |
392 | ||
393 | #ifdef CONFIG_MODULES | |
394 | /* | |
395 | * Examine the existing instructions for __ftrace_make_call. | |
396 | * They should effectively be a NOP, and follow formal constraints, | |
397 | * depending on the ABI. Return false if they don't. | |
398 | */ | |
399 | static bool expected_nop_sequence(void *ip, ppc_inst_t op0, ppc_inst_t op1) | |
400 | { | |
401 | if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) | |
402 | return ppc_inst_equal(op0, ppc_inst(PPC_RAW_NOP())); | |
403 | else | |
404 | return ppc_inst_equal(op0, ppc_inst(PPC_RAW_BRANCH(8))) && | |
405 | ppc_inst_equal(op1, ppc_inst(PPC_INST_LD_TOC)); | |
406 | } | |
407 | ||
408 | static int | |
409 | __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) | |
410 | { | |
411 | ppc_inst_t op[2]; | |
412 | void *ip = (void *)rec->ip; | |
413 | unsigned long entry, ptr, tramp; | |
414 | struct module *mod = rec->arch.mod; | |
415 | ||
416 | /* read where this goes */ | |
417 | if (copy_inst_from_kernel_nofault(op, ip)) | |
418 | return -EFAULT; | |
419 | ||
420 | if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && | |
421 | copy_inst_from_kernel_nofault(op + 1, ip + 4)) | |
422 | return -EFAULT; | |
423 | ||
424 | if (!expected_nop_sequence(ip, op[0], op[1])) { | |
425 | pr_err("Unexpected call sequence at %p: %08lx %08lx\n", ip, | |
426 | ppc_inst_as_ulong(op[0]), ppc_inst_as_ulong(op[1])); | |
427 | return -EINVAL; | |
428 | } | |
429 | ||
430 | /* If we never set up ftrace trampoline(s), then bail */ | |
431 | if (!mod->arch.tramp || | |
432 | (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && !mod->arch.tramp_regs)) { | |
433 | pr_err("No ftrace trampoline\n"); | |
434 | return -EINVAL; | |
435 | } | |
436 | ||
437 | if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && rec->flags & FTRACE_FL_REGS) | |
438 | tramp = mod->arch.tramp_regs; | |
439 | else | |
440 | tramp = mod->arch.tramp; | |
441 | ||
442 | if (module_trampoline_target(mod, tramp, &ptr)) { | |
443 | pr_err("Failed to get trampoline target\n"); | |
444 | return -EFAULT; | |
445 | } | |
446 | ||
447 | pr_devel("trampoline target %lx", ptr); | |
448 | ||
449 | entry = ppc_global_function_entry((void *)addr); | |
450 | /* This should match what was called */ | |
451 | if (ptr != entry) { | |
452 | pr_err("addr %lx does not match expected %lx\n", ptr, entry); | |
453 | return -EINVAL; | |
454 | } | |
455 | ||
456 | if (patch_branch(ip, tramp, BRANCH_SET_LINK)) { | |
457 | pr_err("REL24 out of range!\n"); | |
458 | return -EINVAL; | |
459 | } | |
460 | ||
461 | return 0; | |
462 | } | |
463 | #else | |
464 | static int __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) | |
465 | { | |
466 | return 0; | |
467 | } | |
468 | #endif /* CONFIG_MODULES */ | |
469 | ||
470 | static int __ftrace_make_call_kernel(struct dyn_ftrace *rec, unsigned long addr) | |
471 | { | |
472 | ppc_inst_t op; | |
473 | void *ip = (void *)rec->ip; | |
474 | unsigned long tramp, entry, ptr; | |
475 | ||
476 | /* Make sure we're being asked to patch branch to a known ftrace addr */ | |
477 | entry = ppc_global_function_entry((void *)ftrace_caller); | |
478 | ptr = ppc_global_function_entry((void *)addr); | |
479 | ||
480 | if (ptr != entry && IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) | |
481 | entry = ppc_global_function_entry((void *)ftrace_regs_caller); | |
482 | ||
483 | if (ptr != entry) { | |
484 | pr_err("Unknown ftrace addr to patch: %ps\n", (void *)ptr); | |
485 | return -EINVAL; | |
486 | } | |
487 | ||
488 | /* Make sure we have a nop */ | |
489 | if (copy_inst_from_kernel_nofault(&op, ip)) { | |
490 | pr_err("Unable to read ftrace location %p\n", ip); | |
491 | return -EFAULT; | |
492 | } | |
493 | ||
494 | if (!ppc_inst_equal(op, ppc_inst(PPC_RAW_NOP()))) { | |
495 | pr_err("Unexpected call sequence at %p: %08lx\n", | |
496 | ip, ppc_inst_as_ulong(op)); | |
497 | return -EINVAL; | |
498 | } | |
499 | ||
500 | tramp = find_ftrace_tramp((unsigned long)ip); | |
501 | if (!tramp) { | |
502 | pr_err("No ftrace trampolines reachable from %ps\n", ip); | |
503 | return -EINVAL; | |
504 | } | |
505 | ||
506 | if (patch_branch(ip, tramp, BRANCH_SET_LINK)) { | |
507 | pr_err("Error patching branch to ftrace tramp!\n"); | |
508 | return -EINVAL; | |
509 | } | |
510 | ||
511 | return 0; | |
512 | } | |
513 | ||
514 | int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) | |
515 | { | |
516 | unsigned long ip = rec->ip; | |
517 | ppc_inst_t old, new; | |
518 | ||
519 | /* | |
520 | * If the calling address is more that 24 bits away, | |
521 | * then we had to use a trampoline to make the call. | |
522 | * Otherwise just update the call site. | |
523 | */ | |
524 | if (test_24bit_addr(ip, addr)) { | |
525 | /* within range */ | |
526 | old = ppc_inst(PPC_RAW_NOP()); | |
527 | new = ftrace_call_replace(ip, addr, 1); | |
528 | return ftrace_modify_code(ip, old, new); | |
529 | } else if (core_kernel_text(ip)) { | |
530 | return __ftrace_make_call_kernel(rec, addr); | |
531 | } else if (!IS_ENABLED(CONFIG_MODULES)) { | |
532 | /* We should not get here without modules */ | |
533 | return -EINVAL; | |
534 | } | |
535 | ||
536 | /* | |
537 | * Out of range jumps are called from modules. | |
538 | * Being that we are converting from nop, it had better | |
539 | * already have a module defined. | |
540 | */ | |
541 | if (!rec->arch.mod) { | |
542 | pr_err("No module loaded\n"); | |
543 | return -EINVAL; | |
544 | } | |
545 | ||
546 | return __ftrace_make_call(rec, addr); | |
547 | } | |
548 | ||
549 | #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS | |
550 | #ifdef CONFIG_MODULES | |
551 | static int | |
552 | __ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, | |
553 | unsigned long addr) | |
554 | { | |
555 | ppc_inst_t op; | |
556 | unsigned long ip = rec->ip; | |
557 | unsigned long entry, ptr, tramp; | |
558 | struct module *mod = rec->arch.mod; | |
559 | ||
560 | /* If we never set up ftrace trampolines, then bail */ | |
561 | if (!mod->arch.tramp || !mod->arch.tramp_regs) { | |
562 | pr_err("No ftrace trampoline\n"); | |
563 | return -EINVAL; | |
564 | } | |
565 | ||
566 | /* read where this goes */ | |
567 | if (copy_inst_from_kernel_nofault(&op, (void *)ip)) { | |
568 | pr_err("Fetching opcode failed.\n"); | |
569 | return -EFAULT; | |
570 | } | |
571 | ||
572 | /* Make sure that this is still a 24bit jump */ | |
573 | if (!is_bl_op(op)) { | |
574 | pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(op)); | |
575 | return -EINVAL; | |
576 | } | |
577 | ||
578 | /* lets find where the pointer goes */ | |
579 | tramp = find_bl_target(ip, op); | |
580 | entry = ppc_global_function_entry((void *)old_addr); | |
581 | ||
582 | pr_devel("ip:%lx jumps to %lx", ip, tramp); | |
583 | ||
584 | if (tramp != entry) { | |
585 | /* old_addr is not within range, so we must have used a trampoline */ | |
586 | if (module_trampoline_target(mod, tramp, &ptr)) { | |
587 | pr_err("Failed to get trampoline target\n"); | |
588 | return -EFAULT; | |
589 | } | |
590 | ||
591 | pr_devel("trampoline target %lx", ptr); | |
592 | ||
593 | /* This should match what was called */ | |
594 | if (ptr != entry) { | |
595 | pr_err("addr %lx does not match expected %lx\n", ptr, entry); | |
596 | return -EINVAL; | |
597 | } | |
598 | } | |
599 | ||
600 | /* The new target may be within range */ | |
601 | if (test_24bit_addr(ip, addr)) { | |
602 | /* within range */ | |
603 | if (patch_branch((u32 *)ip, addr, BRANCH_SET_LINK)) { | |
604 | pr_err("REL24 out of range!\n"); | |
605 | return -EINVAL; | |
606 | } | |
607 | ||
608 | return 0; | |
609 | } | |
610 | ||
611 | if (rec->flags & FTRACE_FL_REGS) | |
612 | tramp = mod->arch.tramp_regs; | |
613 | else | |
614 | tramp = mod->arch.tramp; | |
615 | ||
616 | if (module_trampoline_target(mod, tramp, &ptr)) { | |
617 | pr_err("Failed to get trampoline target\n"); | |
618 | return -EFAULT; | |
619 | } | |
620 | ||
621 | pr_devel("trampoline target %lx", ptr); | |
622 | ||
623 | entry = ppc_global_function_entry((void *)addr); | |
624 | /* This should match what was called */ | |
625 | if (ptr != entry) { | |
626 | pr_err("addr %lx does not match expected %lx\n", ptr, entry); | |
627 | return -EINVAL; | |
628 | } | |
629 | ||
630 | if (patch_branch((u32 *)ip, tramp, BRANCH_SET_LINK)) { | |
631 | pr_err("REL24 out of range!\n"); | |
632 | return -EINVAL; | |
633 | } | |
634 | ||
635 | return 0; | |
636 | } | |
637 | #else | |
638 | static int __ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr) | |
639 | { | |
640 | return 0; | |
641 | } | |
642 | #endif | |
643 | ||
644 | int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, | |
645 | unsigned long addr) | |
646 | { | |
647 | unsigned long ip = rec->ip; | |
648 | ppc_inst_t old, new; | |
649 | ||
650 | /* | |
651 | * If the calling address is more that 24 bits away, | |
652 | * then we had to use a trampoline to make the call. | |
653 | * Otherwise just update the call site. | |
654 | */ | |
655 | if (test_24bit_addr(ip, addr) && test_24bit_addr(ip, old_addr)) { | |
656 | /* within range */ | |
657 | old = ftrace_call_replace(ip, old_addr, 1); | |
658 | new = ftrace_call_replace(ip, addr, 1); | |
659 | return ftrace_modify_code(ip, old, new); | |
660 | } else if (core_kernel_text(ip)) { | |
661 | /* | |
662 | * We always patch out of range locations to go to the regs | |
663 | * variant, so there is nothing to do here | |
664 | */ | |
665 | return 0; | |
666 | } else if (!IS_ENABLED(CONFIG_MODULES)) { | |
667 | /* We should not get here without modules */ | |
668 | return -EINVAL; | |
669 | } | |
670 | ||
671 | /* | |
672 | * Out of range jumps are called from modules. | |
673 | */ | |
674 | if (!rec->arch.mod) { | |
675 | pr_err("No module loaded\n"); | |
676 | return -EINVAL; | |
677 | } | |
678 | ||
679 | return __ftrace_modify_call(rec, old_addr, addr); | |
680 | } | |
681 | #endif | |
682 | ||
683 | int ftrace_update_ftrace_func(ftrace_func_t func) | |
684 | { | |
685 | unsigned long ip = (unsigned long)(&ftrace_call); | |
686 | ppc_inst_t old, new; | |
687 | int ret; | |
688 | ||
689 | old = ppc_inst_read((u32 *)&ftrace_call); | |
690 | new = ftrace_call_replace(ip, (unsigned long)func, 1); | |
691 | ret = ftrace_modify_code(ip, old, new); | |
692 | ||
693 | /* Also update the regs callback function */ | |
694 | if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && !ret) { | |
695 | ip = (unsigned long)(&ftrace_regs_call); | |
696 | old = ppc_inst_read((u32 *)&ftrace_regs_call); | |
697 | new = ftrace_call_replace(ip, (unsigned long)func, 1); | |
698 | ret = ftrace_modify_code(ip, old, new); | |
699 | } | |
700 | ||
701 | return ret; | |
702 | } | |
703 | ||
704 | /* | |
705 | * Use the default ftrace_modify_all_code, but without | |
706 | * stop_machine(). | |
707 | */ | |
708 | void arch_ftrace_update_code(int command) | |
709 | { | |
710 | ftrace_modify_all_code(command); | |
711 | } | |
712 | ||
713 | #ifdef CONFIG_PPC64 | |
714 | #define PACATOC offsetof(struct paca_struct, kernel_toc) | |
715 | ||
716 | extern unsigned int ftrace_tramp_text[], ftrace_tramp_init[]; | |
717 | ||
718 | void ftrace_free_init_tramp(void) | |
719 | { | |
720 | int i; | |
721 | ||
722 | for (i = 0; i < NUM_FTRACE_TRAMPS && ftrace_tramps[i]; i++) | |
723 | if (ftrace_tramps[i] == (unsigned long)ftrace_tramp_init) { | |
724 | ftrace_tramps[i] = 0; | |
725 | return; | |
726 | } | |
727 | } | |
728 | ||
729 | int __init ftrace_dyn_arch_init(void) | |
730 | { | |
731 | int i; | |
732 | unsigned int *tramp[] = { ftrace_tramp_text, ftrace_tramp_init }; | |
733 | u32 stub_insns[] = { | |
734 | PPC_RAW_LD(_R12, _R13, PACATOC), | |
735 | PPC_RAW_ADDIS(_R12, _R12, 0), | |
736 | PPC_RAW_ADDI(_R12, _R12, 0), | |
737 | PPC_RAW_MTCTR(_R12), | |
738 | PPC_RAW_BCTR() | |
739 | }; | |
740 | unsigned long addr; | |
741 | long reladdr; | |
742 | ||
743 | if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) | |
744 | addr = ppc_global_function_entry((void *)ftrace_regs_caller); | |
745 | else | |
746 | addr = ppc_global_function_entry((void *)ftrace_caller); | |
747 | ||
748 | reladdr = addr - kernel_toc_addr(); | |
749 | ||
750 | if (reladdr >= SZ_2G || reladdr < -(long)SZ_2G) { | |
751 | pr_err("Address of %ps out of range of kernel_toc.\n", | |
752 | (void *)addr); | |
753 | return -1; | |
754 | } | |
755 | ||
756 | for (i = 0; i < 2; i++) { | |
757 | memcpy(tramp[i], stub_insns, sizeof(stub_insns)); | |
758 | tramp[i][1] |= PPC_HA(reladdr); | |
759 | tramp[i][2] |= PPC_LO(reladdr); | |
760 | add_ftrace_tramp((unsigned long)tramp[i]); | |
761 | } | |
762 | ||
763 | return 0; | |
764 | } | |
765 | #endif | |
766 | ||
767 | #ifdef CONFIG_FUNCTION_GRAPH_TRACER | |
768 | ||
769 | extern void ftrace_graph_call(void); | |
770 | extern void ftrace_graph_stub(void); | |
771 | ||
772 | static int ftrace_modify_ftrace_graph_caller(bool enable) | |
773 | { | |
774 | unsigned long ip = (unsigned long)(&ftrace_graph_call); | |
775 | unsigned long addr = (unsigned long)(&ftrace_graph_caller); | |
776 | unsigned long stub = (unsigned long)(&ftrace_graph_stub); | |
777 | ppc_inst_t old, new; | |
778 | ||
779 | if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_ARGS)) | |
780 | return 0; | |
781 | ||
782 | old = ftrace_call_replace(ip, enable ? stub : addr, 0); | |
783 | new = ftrace_call_replace(ip, enable ? addr : stub, 0); | |
784 | ||
785 | return ftrace_modify_code(ip, old, new); | |
786 | } | |
787 | ||
788 | int ftrace_enable_ftrace_graph_caller(void) | |
789 | { | |
790 | return ftrace_modify_ftrace_graph_caller(true); | |
791 | } | |
792 | ||
793 | int ftrace_disable_ftrace_graph_caller(void) | |
794 | { | |
795 | return ftrace_modify_ftrace_graph_caller(false); | |
796 | } | |
797 | ||
798 | /* | |
799 | * Hook the return address and push it in the stack of return addrs | |
800 | * in current thread info. Return the address we want to divert to. | |
801 | */ | |
802 | static unsigned long | |
803 | __prepare_ftrace_return(unsigned long parent, unsigned long ip, unsigned long sp) | |
804 | { | |
805 | unsigned long return_hooker; | |
806 | int bit; | |
807 | ||
808 | if (unlikely(ftrace_graph_is_dead())) | |
809 | goto out; | |
810 | ||
811 | if (unlikely(atomic_read(¤t->tracing_graph_pause))) | |
812 | goto out; | |
813 | ||
814 | bit = ftrace_test_recursion_trylock(ip, parent); | |
815 | if (bit < 0) | |
816 | goto out; | |
817 | ||
818 | return_hooker = ppc_function_entry(return_to_handler); | |
819 | ||
820 | if (!function_graph_enter(parent, ip, 0, (unsigned long *)sp)) | |
821 | parent = return_hooker; | |
822 | ||
823 | ftrace_test_recursion_unlock(bit); | |
824 | out: | |
825 | return parent; | |
826 | } | |
827 | ||
828 | #ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS | |
829 | void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, | |
830 | struct ftrace_ops *op, struct ftrace_regs *fregs) | |
831 | { | |
832 | fregs->regs.link = __prepare_ftrace_return(parent_ip, ip, fregs->regs.gpr[1]); | |
833 | } | |
834 | #else | |
835 | unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip, | |
836 | unsigned long sp) | |
837 | { | |
838 | return __prepare_ftrace_return(parent, ip, sp); | |
839 | } | |
840 | #endif | |
841 | #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ | |
842 | ||
843 | #ifdef CONFIG_PPC64_ELF_ABI_V1 | |
844 | char *arch_ftrace_match_adjust(char *str, const char *search) | |
845 | { | |
846 | if (str[0] == '.' && search[0] != '.') | |
847 | return str + 1; | |
848 | else | |
849 | return str; | |
850 | } | |
851 | #endif /* CONFIG_PPC64_ELF_ABI_V1 */ |