1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Code for replacing ftrace calls with jumps.
4 *
5 * Copyright (C) 2007-2008 Steven Rostedt <[email protected]>
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/text-patching.h>
27 #include <asm/ftrace.h>
28 #include <asm/syscall.h>
29 #include <asm/inst.h>
30 #include <asm/sections.h>
31
32 #define NUM_FTRACE_TRAMPS 2
33 static unsigned long ftrace_tramps[NUM_FTRACE_TRAMPS];
34
ftrace_call_adjust(unsigned long addr)35 unsigned long ftrace_call_adjust(unsigned long addr)
36 {
37 if (addr >= (unsigned long)__exittext_begin && addr < (unsigned long)__exittext_end)
38 return 0;
39
40 if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY) &&
41 !IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) {
42 addr += MCOUNT_INSN_SIZE;
43 if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS))
44 addr += MCOUNT_INSN_SIZE;
45 }
46
47 return addr;
48 }
49
ftrace_create_branch_inst(unsigned long ip,unsigned long addr,int link)50 static ppc_inst_t ftrace_create_branch_inst(unsigned long ip, unsigned long addr, int link)
51 {
52 ppc_inst_t op;
53
54 WARN_ON(!is_offset_in_branch_range(addr - ip));
55 create_branch(&op, (u32 *)ip, addr, link ? BRANCH_SET_LINK : 0);
56
57 return op;
58 }
59
ftrace_read_inst(unsigned long ip,ppc_inst_t * op)60 static inline int ftrace_read_inst(unsigned long ip, ppc_inst_t *op)
61 {
62 if (copy_inst_from_kernel_nofault(op, (void *)ip)) {
63 pr_err("0x%lx: fetching instruction failed\n", ip);
64 return -EFAULT;
65 }
66
67 return 0;
68 }
69
ftrace_validate_inst(unsigned long ip,ppc_inst_t inst)70 static inline int ftrace_validate_inst(unsigned long ip, ppc_inst_t inst)
71 {
72 ppc_inst_t op;
73 int ret;
74
75 ret = ftrace_read_inst(ip, &op);
76 if (!ret && !ppc_inst_equal(op, inst)) {
77 pr_err("0x%lx: expected (%08lx) != found (%08lx)\n",
78 ip, ppc_inst_as_ulong(inst), ppc_inst_as_ulong(op));
79 ret = -EINVAL;
80 }
81
82 return ret;
83 }
84
ftrace_modify_code(unsigned long ip,ppc_inst_t old,ppc_inst_t new)85 static inline int ftrace_modify_code(unsigned long ip, ppc_inst_t old, ppc_inst_t new)
86 {
87 int ret = ftrace_validate_inst(ip, old);
88
89 if (!ret && !ppc_inst_equal(old, new))
90 ret = patch_instruction((u32 *)ip, new);
91
92 return ret;
93 }
94
is_bl_op(ppc_inst_t op)95 static int is_bl_op(ppc_inst_t op)
96 {
97 return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BL(0);
98 }
99
find_ftrace_tramp(unsigned long ip)100 static unsigned long find_ftrace_tramp(unsigned long ip)
101 {
102 int i;
103
104 for (i = 0; i < NUM_FTRACE_TRAMPS; i++)
105 if (!ftrace_tramps[i])
106 continue;
107 else if (is_offset_in_branch_range(ftrace_tramps[i] - ip))
108 return ftrace_tramps[i];
109
110 return 0;
111 }
112
113 #ifdef CONFIG_MODULES
ftrace_lookup_module_stub(unsigned long ip,unsigned long addr)114 static unsigned long ftrace_lookup_module_stub(unsigned long ip, unsigned long addr)
115 {
116 struct module *mod = NULL;
117
118 preempt_disable();
119 mod = __module_text_address(ip);
120 preempt_enable();
121
122 if (!mod)
123 pr_err("No module loaded at addr=%lx\n", ip);
124
125 return (addr == (unsigned long)ftrace_caller ? mod->arch.tramp : mod->arch.tramp_regs);
126 }
127 #else
ftrace_lookup_module_stub(unsigned long ip,unsigned long addr)128 static unsigned long ftrace_lookup_module_stub(unsigned long ip, unsigned long addr)
129 {
130 return 0;
131 }
132 #endif
133
ftrace_get_ool_stub(struct dyn_ftrace * rec)134 static unsigned long ftrace_get_ool_stub(struct dyn_ftrace *rec)
135 {
136 #ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
137 return rec->arch.ool_stub;
138 #else
139 BUILD_BUG();
140 #endif
141 }
142
ftrace_get_call_inst(struct dyn_ftrace * rec,unsigned long addr,ppc_inst_t * call_inst)143 static int ftrace_get_call_inst(struct dyn_ftrace *rec, unsigned long addr, ppc_inst_t *call_inst)
144 {
145 unsigned long ip;
146 unsigned long stub;
147
148 if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE))
149 ip = ftrace_get_ool_stub(rec) + MCOUNT_INSN_SIZE; /* second instruction in stub */
150 else
151 ip = rec->ip;
152
153 if (!is_offset_in_branch_range(addr - ip) && addr != FTRACE_ADDR &&
154 addr != FTRACE_REGS_ADDR) {
155 /* This can only happen with ftrace direct */
156 if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS)) {
157 pr_err("0x%lx (0x%lx): Unexpected target address 0x%lx\n",
158 ip, rec->ip, addr);
159 return -EINVAL;
160 }
161 addr = FTRACE_ADDR;
162 }
163
164 if (is_offset_in_branch_range(addr - ip))
165 /* Within range */
166 stub = addr;
167 else if (core_kernel_text(ip))
168 /* We would be branching to one of our ftrace stubs */
169 stub = find_ftrace_tramp(ip);
170 else
171 stub = ftrace_lookup_module_stub(ip, addr);
172
173 if (!stub) {
174 pr_err("0x%lx (0x%lx): No ftrace stubs reachable\n", ip, rec->ip);
175 return -EINVAL;
176 }
177
178 *call_inst = ftrace_create_branch_inst(ip, stub, 1);
179 return 0;
180 }
181
ftrace_init_ool_stub(struct module * mod,struct dyn_ftrace * rec)182 static int ftrace_init_ool_stub(struct module *mod, struct dyn_ftrace *rec)
183 {
184 #ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
185 static int ool_stub_text_index, ool_stub_text_end_index, ool_stub_inittext_index;
186 int ret = 0, ool_stub_count, *ool_stub_index;
187 ppc_inst_t inst;
188 /*
189 * See ftrace_entry.S if changing the below instruction sequence, as we rely on
190 * decoding the last branch instruction here to recover the correct function ip.
191 */
192 struct ftrace_ool_stub *ool_stub, ool_stub_template = {
193 .insn = {
194 PPC_RAW_MFLR(_R0),
195 PPC_RAW_NOP(), /* bl ftrace_caller */
196 PPC_RAW_MTLR(_R0),
197 PPC_RAW_NOP() /* b rec->ip + 4 */
198 }
199 };
200
201 WARN_ON(rec->arch.ool_stub);
202
203 if (is_kernel_inittext(rec->ip)) {
204 ool_stub = ftrace_ool_stub_inittext;
205 ool_stub_index = &ool_stub_inittext_index;
206 ool_stub_count = ftrace_ool_stub_inittext_count;
207 } else if (is_kernel_text(rec->ip)) {
208 /*
209 * ftrace records are sorted, so we first use up the stub area within .text
210 * (ftrace_ool_stub_text) before using the area at the end of .text
211 * (ftrace_ool_stub_text_end), unless the stub is out of range of the record.
212 */
213 if (ool_stub_text_index >= ftrace_ool_stub_text_count ||
214 !is_offset_in_branch_range((long)rec->ip -
215 (long)&ftrace_ool_stub_text[ool_stub_text_index])) {
216 ool_stub = ftrace_ool_stub_text_end;
217 ool_stub_index = &ool_stub_text_end_index;
218 ool_stub_count = ftrace_ool_stub_text_end_count;
219 } else {
220 ool_stub = ftrace_ool_stub_text;
221 ool_stub_index = &ool_stub_text_index;
222 ool_stub_count = ftrace_ool_stub_text_count;
223 }
224 #ifdef CONFIG_MODULES
225 } else if (mod) {
226 ool_stub = mod->arch.ool_stubs;
227 ool_stub_index = &mod->arch.ool_stub_index;
228 ool_stub_count = mod->arch.ool_stub_count;
229 #endif
230 } else {
231 return -EINVAL;
232 }
233
234 ool_stub += (*ool_stub_index)++;
235
236 if (WARN_ON(*ool_stub_index > ool_stub_count))
237 return -EINVAL;
238
239 if (!is_offset_in_branch_range((long)rec->ip - (long)&ool_stub->insn[0]) ||
240 !is_offset_in_branch_range((long)(rec->ip + MCOUNT_INSN_SIZE) -
241 (long)&ool_stub->insn[3])) {
242 pr_err("%s: ftrace ool stub out of range (%p -> %p).\n",
243 __func__, (void *)rec->ip, (void *)&ool_stub->insn[0]);
244 return -EINVAL;
245 }
246
247 rec->arch.ool_stub = (unsigned long)&ool_stub->insn[0];
248
249 /* bl ftrace_caller */
250 if (!mod)
251 ret = ftrace_get_call_inst(rec, (unsigned long)ftrace_caller, &inst);
252 #ifdef CONFIG_MODULES
253 else
254 /*
255 * We can't use ftrace_get_call_inst() since that uses
256 * __module_text_address(rec->ip) to look up the module.
257 * But, since the module is not fully formed at this stage,
258 * the lookup fails. We know the target though, so generate
259 * the branch inst directly.
260 */
261 inst = ftrace_create_branch_inst(ftrace_get_ool_stub(rec) + MCOUNT_INSN_SIZE,
262 mod->arch.tramp, 1);
263 #endif
264 ool_stub_template.insn[1] = ppc_inst_val(inst);
265
266 /* b rec->ip + 4 */
267 if (!ret && create_branch(&inst, &ool_stub->insn[3], rec->ip + MCOUNT_INSN_SIZE, 0))
268 return -EINVAL;
269 ool_stub_template.insn[3] = ppc_inst_val(inst);
270
271 if (!ret)
272 ret = patch_instructions((u32 *)ool_stub, (u32 *)&ool_stub_template,
273 sizeof(ool_stub_template), false);
274
275 return ret;
276 #else /* !CONFIG_PPC_FTRACE_OUT_OF_LINE */
277 BUILD_BUG();
278 #endif
279 }
280
281 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS
powerpc_rec_get_ops(struct dyn_ftrace * rec)282 static const struct ftrace_ops *powerpc_rec_get_ops(struct dyn_ftrace *rec)
283 {
284 const struct ftrace_ops *ops = NULL;
285
286 if (rec->flags & FTRACE_FL_CALL_OPS_EN) {
287 ops = ftrace_find_unique_ops(rec);
288 WARN_ON_ONCE(!ops);
289 }
290
291 if (!ops)
292 ops = &ftrace_list_ops;
293
294 return ops;
295 }
296
ftrace_rec_set_ops(struct dyn_ftrace * rec,const struct ftrace_ops * ops)297 static int ftrace_rec_set_ops(struct dyn_ftrace *rec, const struct ftrace_ops *ops)
298 {
299 if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE))
300 return patch_ulong((void *)(ftrace_get_ool_stub(rec) - sizeof(unsigned long)),
301 (unsigned long)ops);
302 else
303 return patch_ulong((void *)(rec->ip - MCOUNT_INSN_SIZE - sizeof(unsigned long)),
304 (unsigned long)ops);
305 }
306
ftrace_rec_set_nop_ops(struct dyn_ftrace * rec)307 static int ftrace_rec_set_nop_ops(struct dyn_ftrace *rec)
308 {
309 return ftrace_rec_set_ops(rec, &ftrace_nop_ops);
310 }
311
ftrace_rec_update_ops(struct dyn_ftrace * rec)312 static int ftrace_rec_update_ops(struct dyn_ftrace *rec)
313 {
314 return ftrace_rec_set_ops(rec, powerpc_rec_get_ops(rec));
315 }
316 #else
ftrace_rec_set_nop_ops(struct dyn_ftrace * rec)317 static int ftrace_rec_set_nop_ops(struct dyn_ftrace *rec) { return 0; }
ftrace_rec_update_ops(struct dyn_ftrace * rec)318 static int ftrace_rec_update_ops(struct dyn_ftrace *rec) { return 0; }
319 #endif
320
321 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
ftrace_modify_call(struct dyn_ftrace * rec,unsigned long old_addr,unsigned long addr)322 int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr)
323 {
324 /* This should never be called since we override ftrace_replace_code() */
325 WARN_ON(1);
326 return -EINVAL;
327 }
328 #endif
329
ftrace_make_call(struct dyn_ftrace * rec,unsigned long addr)330 int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
331 {
332 ppc_inst_t old, new;
333 unsigned long ip = rec->ip;
334 int ret = 0;
335
336 /* This can only ever be called during module load */
337 if (WARN_ON(!IS_ENABLED(CONFIG_MODULES) || core_kernel_text(ip)))
338 return -EINVAL;
339
340 old = ppc_inst(PPC_RAW_NOP());
341 if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) {
342 ip = ftrace_get_ool_stub(rec) + MCOUNT_INSN_SIZE; /* second instruction in stub */
343 ret = ftrace_get_call_inst(rec, (unsigned long)ftrace_caller, &old);
344 }
345
346 ret |= ftrace_get_call_inst(rec, addr, &new);
347
348 if (!ret)
349 ret = ftrace_modify_code(ip, old, new);
350
351 ret = ftrace_rec_update_ops(rec);
352 if (ret)
353 return ret;
354
355 if (!ret && IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE))
356 ret = ftrace_modify_code(rec->ip, ppc_inst(PPC_RAW_NOP()),
357 ppc_inst(PPC_RAW_BRANCH((long)ftrace_get_ool_stub(rec) - (long)rec->ip)));
358
359 return ret;
360 }
361
ftrace_make_nop(struct module * mod,struct dyn_ftrace * rec,unsigned long addr)362 int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr)
363 {
364 /*
365 * This should never be called since we override ftrace_replace_code(),
366 * as well as ftrace_init_nop()
367 */
368 WARN_ON(1);
369 return -EINVAL;
370 }
371
ftrace_replace_code(int enable)372 void ftrace_replace_code(int enable)
373 {
374 ppc_inst_t old, new, call_inst, new_call_inst;
375 ppc_inst_t nop_inst = ppc_inst(PPC_RAW_NOP());
376 unsigned long ip, new_addr, addr;
377 struct ftrace_rec_iter *iter;
378 struct dyn_ftrace *rec;
379 int ret = 0, update;
380
381 for_ftrace_rec_iter(iter) {
382 rec = ftrace_rec_iter_record(iter);
383 ip = rec->ip;
384
385 if (rec->flags & FTRACE_FL_DISABLED && !(rec->flags & FTRACE_FL_ENABLED))
386 continue;
387
388 addr = ftrace_get_addr_curr(rec);
389 new_addr = ftrace_get_addr_new(rec);
390 update = ftrace_update_record(rec, enable);
391
392 if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE) && update != FTRACE_UPDATE_IGNORE) {
393 ip = ftrace_get_ool_stub(rec) + MCOUNT_INSN_SIZE;
394 ret = ftrace_get_call_inst(rec, (unsigned long)ftrace_caller, &nop_inst);
395 if (ret)
396 goto out;
397 }
398
399 switch (update) {
400 case FTRACE_UPDATE_IGNORE:
401 default:
402 continue;
403 case FTRACE_UPDATE_MODIFY_CALL:
404 ret = ftrace_get_call_inst(rec, new_addr, &new_call_inst);
405 ret |= ftrace_get_call_inst(rec, addr, &call_inst);
406 ret |= ftrace_rec_update_ops(rec);
407 old = call_inst;
408 new = new_call_inst;
409 break;
410 case FTRACE_UPDATE_MAKE_NOP:
411 ret = ftrace_get_call_inst(rec, addr, &call_inst);
412 ret |= ftrace_rec_set_nop_ops(rec);
413 old = call_inst;
414 new = nop_inst;
415 break;
416 case FTRACE_UPDATE_MAKE_CALL:
417 ret = ftrace_get_call_inst(rec, new_addr, &call_inst);
418 ret |= ftrace_rec_update_ops(rec);
419 old = nop_inst;
420 new = call_inst;
421 break;
422 }
423
424 if (!ret)
425 ret = ftrace_modify_code(ip, old, new);
426
427 if (!ret && IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE) &&
428 (update == FTRACE_UPDATE_MAKE_NOP || update == FTRACE_UPDATE_MAKE_CALL)) {
429 /* Update the actual ftrace location */
430 call_inst = ppc_inst(PPC_RAW_BRANCH((long)ftrace_get_ool_stub(rec) -
431 (long)rec->ip));
432 nop_inst = ppc_inst(PPC_RAW_NOP());
433 ip = rec->ip;
434
435 if (update == FTRACE_UPDATE_MAKE_NOP)
436 ret = ftrace_modify_code(ip, call_inst, nop_inst);
437 else
438 ret = ftrace_modify_code(ip, nop_inst, call_inst);
439
440 if (ret)
441 goto out;
442 }
443
444 if (ret)
445 goto out;
446 }
447
448 out:
449 if (ret)
450 ftrace_bug(ret, rec);
451 return;
452 }
453
ftrace_init_nop(struct module * mod,struct dyn_ftrace * rec)454 int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
455 {
456 unsigned long addr, ip = rec->ip;
457 ppc_inst_t old, new;
458 int ret = 0;
459
460 /* Verify instructions surrounding the ftrace location */
461 if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)) {
462 /* Expect nops */
463 if (!IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE))
464 ret = ftrace_validate_inst(ip - 4, ppc_inst(PPC_RAW_NOP()));
465 if (!ret)
466 ret = ftrace_validate_inst(ip, ppc_inst(PPC_RAW_NOP()));
467 } else if (IS_ENABLED(CONFIG_PPC32)) {
468 /* Expected sequence: 'mflr r0', 'stw r0,4(r1)', 'bl _mcount' */
469 ret = ftrace_validate_inst(ip - 8, ppc_inst(PPC_RAW_MFLR(_R0)));
470 if (ret)
471 return ret;
472 ret = ftrace_modify_code(ip - 4, ppc_inst(PPC_RAW_STW(_R0, _R1, 4)),
473 ppc_inst(PPC_RAW_NOP()));
474 } else if (IS_ENABLED(CONFIG_MPROFILE_KERNEL)) {
475 /* Expected sequence: 'mflr r0', ['std r0,16(r1)'], 'bl _mcount' */
476 ret = ftrace_read_inst(ip - 4, &old);
477 if (!ret && !ppc_inst_equal(old, ppc_inst(PPC_RAW_MFLR(_R0)))) {
478 /* Gcc v5.x emit the additional 'std' instruction, gcc v6.x don't */
479 ret = ftrace_validate_inst(ip - 8, ppc_inst(PPC_RAW_MFLR(_R0)));
480 if (ret)
481 return ret;
482 ret = ftrace_modify_code(ip - 4, ppc_inst(PPC_RAW_STD(_R0, _R1, 16)),
483 ppc_inst(PPC_RAW_NOP()));
484 }
485 } else {
486 return -EINVAL;
487 }
488
489 if (ret)
490 return ret;
491
492 /* Set up out-of-line stub */
493 if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE))
494 return ftrace_init_ool_stub(mod, rec);
495
496 /* Nop-out the ftrace location */
497 new = ppc_inst(PPC_RAW_NOP());
498 addr = MCOUNT_ADDR;
499 if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)) {
500 /* we instead patch-in the 'mflr r0' */
501 old = ppc_inst(PPC_RAW_NOP());
502 new = ppc_inst(PPC_RAW_MFLR(_R0));
503 ret = ftrace_modify_code(ip - 4, old, new);
504 } else if (is_offset_in_branch_range(addr - ip)) {
505 /* Within range */
506 old = ftrace_create_branch_inst(ip, addr, 1);
507 ret = ftrace_modify_code(ip, old, new);
508 } else if (core_kernel_text(ip) || (IS_ENABLED(CONFIG_MODULES) && mod)) {
509 /*
510 * We would be branching to a linker-generated stub, or to the module _mcount
511 * stub. Let's just confirm we have a 'bl' here.
512 */
513 ret = ftrace_read_inst(ip, &old);
514 if (ret)
515 return ret;
516 if (!is_bl_op(old)) {
517 pr_err("0x%lx: expected (bl) != found (%08lx)\n", ip, ppc_inst_as_ulong(old));
518 return -EINVAL;
519 }
520 ret = patch_instruction((u32 *)ip, new);
521 } else {
522 return -EINVAL;
523 }
524
525 return ret;
526 }
527
ftrace_update_ftrace_func(ftrace_func_t func)528 int ftrace_update_ftrace_func(ftrace_func_t func)
529 {
530 unsigned long ip = (unsigned long)(&ftrace_call);
531 ppc_inst_t old, new;
532 int ret;
533
534 /*
535 * When using CALL_OPS, the function to call is associated with the
536 * call site, and we don't have a global function pointer to update.
537 */
538 if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS))
539 return 0;
540
541 old = ppc_inst_read((u32 *)&ftrace_call);
542 new = ftrace_create_branch_inst(ip, ppc_function_entry(func), 1);
543 ret = ftrace_modify_code(ip, old, new);
544
545 /* Also update the regs callback function */
546 if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && !ret) {
547 ip = (unsigned long)(&ftrace_regs_call);
548 old = ppc_inst_read((u32 *)&ftrace_regs_call);
549 new = ftrace_create_branch_inst(ip, ppc_function_entry(func), 1);
550 ret = ftrace_modify_code(ip, old, new);
551 }
552
553 return ret;
554 }
555
556 /*
557 * Use the default ftrace_modify_all_code, but without
558 * stop_machine().
559 */
arch_ftrace_update_code(int command)560 void arch_ftrace_update_code(int command)
561 {
562 ftrace_modify_all_code(command);
563 }
564
ftrace_free_init_tramp(void)565 void ftrace_free_init_tramp(void)
566 {
567 int i;
568
569 for (i = 0; i < NUM_FTRACE_TRAMPS && ftrace_tramps[i]; i++)
570 if (ftrace_tramps[i] == (unsigned long)ftrace_tramp_init) {
571 ftrace_tramps[i] = 0;
572 return;
573 }
574 }
575
add_ftrace_tramp(unsigned long tramp)576 static void __init add_ftrace_tramp(unsigned long tramp)
577 {
578 int i;
579
580 for (i = 0; i < NUM_FTRACE_TRAMPS; i++)
581 if (!ftrace_tramps[i]) {
582 ftrace_tramps[i] = tramp;
583 return;
584 }
585 }
586
ftrace_dyn_arch_init(void)587 int __init ftrace_dyn_arch_init(void)
588 {
589 unsigned int *tramp[] = { ftrace_tramp_text, ftrace_tramp_init };
590 unsigned long addr = FTRACE_REGS_ADDR;
591 long reladdr;
592 int i;
593 u32 stub_insns[] = {
594 #ifdef CONFIG_PPC_KERNEL_PCREL
595 /* pla r12,addr */
596 PPC_PREFIX_MLS | __PPC_PRFX_R(1),
597 PPC_INST_PADDI | ___PPC_RT(_R12),
598 PPC_RAW_MTCTR(_R12),
599 PPC_RAW_BCTR()
600 #elif defined(CONFIG_PPC64)
601 PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernel_toc)),
602 PPC_RAW_ADDIS(_R12, _R12, 0),
603 PPC_RAW_ADDI(_R12, _R12, 0),
604 PPC_RAW_MTCTR(_R12),
605 PPC_RAW_BCTR()
606 #else
607 PPC_RAW_LIS(_R12, 0),
608 PPC_RAW_ADDI(_R12, _R12, 0),
609 PPC_RAW_MTCTR(_R12),
610 PPC_RAW_BCTR()
611 #endif
612 };
613
614 if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) {
615 for (i = 0; i < 2; i++) {
616 reladdr = addr - (unsigned long)tramp[i];
617
618 if (reladdr >= (long)SZ_8G || reladdr < -(long)SZ_8G) {
619 pr_err("Address of %ps out of range of pcrel address.\n",
620 (void *)addr);
621 return -1;
622 }
623
624 memcpy(tramp[i], stub_insns, sizeof(stub_insns));
625 tramp[i][0] |= IMM_H18(reladdr);
626 tramp[i][1] |= IMM_L(reladdr);
627 add_ftrace_tramp((unsigned long)tramp[i]);
628 }
629 } else if (IS_ENABLED(CONFIG_PPC64)) {
630 reladdr = addr - kernel_toc_addr();
631
632 if (reladdr >= (long)SZ_2G || reladdr < -(long long)SZ_2G) {
633 pr_err("Address of %ps out of range of kernel_toc.\n",
634 (void *)addr);
635 return -1;
636 }
637
638 for (i = 0; i < 2; i++) {
639 memcpy(tramp[i], stub_insns, sizeof(stub_insns));
640 tramp[i][1] |= PPC_HA(reladdr);
641 tramp[i][2] |= PPC_LO(reladdr);
642 add_ftrace_tramp((unsigned long)tramp[i]);
643 }
644 } else {
645 for (i = 0; i < 2; i++) {
646 memcpy(tramp[i], stub_insns, sizeof(stub_insns));
647 tramp[i][0] |= PPC_HA(addr);
648 tramp[i][1] |= PPC_LO(addr);
649 add_ftrace_tramp((unsigned long)tramp[i]);
650 }
651 }
652
653 return 0;
654 }
655
656 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
ftrace_graph_func(unsigned long ip,unsigned long parent_ip,struct ftrace_ops * op,struct ftrace_regs * fregs)657 void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
658 struct ftrace_ops *op, struct ftrace_regs *fregs)
659 {
660 unsigned long sp = arch_ftrace_regs(fregs)->regs.gpr[1];
661
662 if (unlikely(ftrace_graph_is_dead()))
663 goto out;
664
665 if (unlikely(atomic_read(¤t->tracing_graph_pause)))
666 goto out;
667
668 if (!function_graph_enter_regs(parent_ip, ip, 0, (unsigned long *)sp, fregs))
669 parent_ip = ppc_function_entry(return_to_handler);
670
671 out:
672 arch_ftrace_regs(fregs)->regs.link = parent_ip;
673 }
674 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
675