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20002ded PM |
1 | /* |
2 | * Performance counter callchain support - powerpc architecture code | |
3 | * | |
4 | * Copyright © 2009 Paul Mackerras, IBM Corporation. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | #include <linux/kernel.h> | |
12 | #include <linux/sched.h> | |
cdd6c482 | 13 | #include <linux/perf_event.h> |
20002ded PM |
14 | #include <linux/percpu.h> |
15 | #include <linux/uaccess.h> | |
16 | #include <linux/mm.h> | |
17 | #include <asm/ptrace.h> | |
18 | #include <asm/pgtable.h> | |
19 | #include <asm/sigcontext.h> | |
20 | #include <asm/ucontext.h> | |
21 | #include <asm/vdso.h> | |
22 | #ifdef CONFIG_PPC64 | |
23 | #include "ppc32.h" | |
24 | #endif | |
25 | ||
20002ded PM |
26 | |
27 | /* | |
28 | * Is sp valid as the address of the next kernel stack frame after prev_sp? | |
29 | * The next frame may be in a different stack area but should not go | |
30 | * back down in the same stack area. | |
31 | */ | |
32 | static int valid_next_sp(unsigned long sp, unsigned long prev_sp) | |
33 | { | |
34 | if (sp & 0xf) | |
35 | return 0; /* must be 16-byte aligned */ | |
36 | if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD)) | |
37 | return 0; | |
38 | if (sp >= prev_sp + STACK_FRAME_OVERHEAD) | |
39 | return 1; | |
40 | /* | |
41 | * sp could decrease when we jump off an interrupt stack | |
42 | * back to the regular process stack. | |
43 | */ | |
44 | if ((sp & ~(THREAD_SIZE - 1)) != (prev_sp & ~(THREAD_SIZE - 1))) | |
45 | return 1; | |
46 | return 0; | |
47 | } | |
48 | ||
49 | static void perf_callchain_kernel(struct pt_regs *regs, | |
50 | struct perf_callchain_entry *entry) | |
51 | { | |
52 | unsigned long sp, next_sp; | |
53 | unsigned long next_ip; | |
54 | unsigned long lr; | |
55 | long level = 0; | |
56 | unsigned long *fp; | |
57 | ||
58 | lr = regs->link; | |
59 | sp = regs->gpr[1]; | |
70791ce9 FW |
60 | perf_callchain_store(entry, PERF_CONTEXT_KERNEL); |
61 | perf_callchain_store(entry, regs->nip); | |
20002ded PM |
62 | |
63 | if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD)) | |
64 | return; | |
65 | ||
66 | for (;;) { | |
67 | fp = (unsigned long *) sp; | |
68 | next_sp = fp[0]; | |
69 | ||
70 | if (next_sp == sp + STACK_INT_FRAME_SIZE && | |
71 | fp[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) { | |
72 | /* | |
73 | * This looks like an interrupt frame for an | |
74 | * interrupt that occurred in the kernel | |
75 | */ | |
76 | regs = (struct pt_regs *)(sp + STACK_FRAME_OVERHEAD); | |
77 | next_ip = regs->nip; | |
78 | lr = regs->link; | |
79 | level = 0; | |
70791ce9 | 80 | perf_callchain_store(entry, PERF_CONTEXT_KERNEL); |
20002ded PM |
81 | |
82 | } else { | |
83 | if (level == 0) | |
84 | next_ip = lr; | |
85 | else | |
86 | next_ip = fp[STACK_FRAME_LR_SAVE]; | |
87 | ||
88 | /* | |
89 | * We can't tell which of the first two addresses | |
90 | * we get are valid, but we can filter out the | |
91 | * obviously bogus ones here. We replace them | |
92 | * with 0 rather than removing them entirely so | |
93 | * that userspace can tell which is which. | |
94 | */ | |
95 | if ((level == 1 && next_ip == lr) || | |
96 | (level <= 1 && !kernel_text_address(next_ip))) | |
97 | next_ip = 0; | |
98 | ||
99 | ++level; | |
100 | } | |
101 | ||
70791ce9 | 102 | perf_callchain_store(entry, next_ip); |
20002ded PM |
103 | if (!valid_next_sp(next_sp, sp)) |
104 | return; | |
105 | sp = next_sp; | |
106 | } | |
107 | } | |
108 | ||
109 | #ifdef CONFIG_PPC64 | |
20002ded PM |
110 | /* |
111 | * On 64-bit we don't want to invoke hash_page on user addresses from | |
112 | * interrupt context, so if the access faults, we read the page tables | |
113 | * to find which page (if any) is mapped and access it directly. | |
114 | */ | |
115 | static int read_user_stack_slow(void __user *ptr, void *ret, int nb) | |
116 | { | |
117 | pgd_t *pgdir; | |
118 | pte_t *ptep, pte; | |
a4fe3ce7 | 119 | unsigned shift; |
20002ded PM |
120 | unsigned long addr = (unsigned long) ptr; |
121 | unsigned long offset; | |
122 | unsigned long pfn; | |
123 | void *kaddr; | |
124 | ||
125 | pgdir = current->mm->pgd; | |
126 | if (!pgdir) | |
127 | return -EFAULT; | |
128 | ||
a4fe3ce7 DG |
129 | ptep = find_linux_pte_or_hugepte(pgdir, addr, &shift); |
130 | if (!shift) | |
131 | shift = PAGE_SHIFT; | |
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132 | |
133 | /* align address to page boundary */ | |
a4fe3ce7 | 134 | offset = addr & ((1UL << shift) - 1); |
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135 | addr -= offset; |
136 | ||
20002ded PM |
137 | if (ptep == NULL) |
138 | return -EFAULT; | |
139 | pte = *ptep; | |
140 | if (!pte_present(pte) || !(pte_val(pte) & _PAGE_USER)) | |
141 | return -EFAULT; | |
142 | pfn = pte_pfn(pte); | |
143 | if (!page_is_ram(pfn)) | |
144 | return -EFAULT; | |
145 | ||
146 | /* no highmem to worry about here */ | |
147 | kaddr = pfn_to_kaddr(pfn); | |
148 | memcpy(ret, kaddr + offset, nb); | |
149 | return 0; | |
150 | } | |
151 | ||
152 | static int read_user_stack_64(unsigned long __user *ptr, unsigned long *ret) | |
153 | { | |
154 | if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned long) || | |
155 | ((unsigned long)ptr & 7)) | |
156 | return -EFAULT; | |
157 | ||
158 | if (!__get_user_inatomic(*ret, ptr)) | |
159 | return 0; | |
160 | ||
161 | return read_user_stack_slow(ptr, ret, 8); | |
162 | } | |
163 | ||
164 | static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret) | |
165 | { | |
166 | if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned int) || | |
167 | ((unsigned long)ptr & 3)) | |
168 | return -EFAULT; | |
169 | ||
170 | if (!__get_user_inatomic(*ret, ptr)) | |
171 | return 0; | |
172 | ||
173 | return read_user_stack_slow(ptr, ret, 4); | |
174 | } | |
175 | ||
176 | static inline int valid_user_sp(unsigned long sp, int is_64) | |
177 | { | |
178 | if (!sp || (sp & 7) || sp > (is_64 ? TASK_SIZE : 0x100000000UL) - 32) | |
179 | return 0; | |
180 | return 1; | |
181 | } | |
182 | ||
183 | /* | |
184 | * 64-bit user processes use the same stack frame for RT and non-RT signals. | |
185 | */ | |
186 | struct signal_frame_64 { | |
187 | char dummy[__SIGNAL_FRAMESIZE]; | |
188 | struct ucontext uc; | |
189 | unsigned long unused[2]; | |
190 | unsigned int tramp[6]; | |
191 | struct siginfo *pinfo; | |
192 | void *puc; | |
193 | struct siginfo info; | |
194 | char abigap[288]; | |
195 | }; | |
196 | ||
197 | static int is_sigreturn_64_address(unsigned long nip, unsigned long fp) | |
198 | { | |
199 | if (nip == fp + offsetof(struct signal_frame_64, tramp)) | |
200 | return 1; | |
201 | if (vdso64_rt_sigtramp && current->mm->context.vdso_base && | |
202 | nip == current->mm->context.vdso_base + vdso64_rt_sigtramp) | |
203 | return 1; | |
204 | return 0; | |
205 | } | |
206 | ||
207 | /* | |
208 | * Do some sanity checking on the signal frame pointed to by sp. | |
209 | * We check the pinfo and puc pointers in the frame. | |
210 | */ | |
211 | static int sane_signal_64_frame(unsigned long sp) | |
212 | { | |
213 | struct signal_frame_64 __user *sf; | |
214 | unsigned long pinfo, puc; | |
215 | ||
216 | sf = (struct signal_frame_64 __user *) sp; | |
217 | if (read_user_stack_64((unsigned long __user *) &sf->pinfo, &pinfo) || | |
218 | read_user_stack_64((unsigned long __user *) &sf->puc, &puc)) | |
219 | return 0; | |
220 | return pinfo == (unsigned long) &sf->info && | |
221 | puc == (unsigned long) &sf->uc; | |
222 | } | |
223 | ||
224 | static void perf_callchain_user_64(struct pt_regs *regs, | |
225 | struct perf_callchain_entry *entry) | |
226 | { | |
227 | unsigned long sp, next_sp; | |
228 | unsigned long next_ip; | |
229 | unsigned long lr; | |
230 | long level = 0; | |
231 | struct signal_frame_64 __user *sigframe; | |
232 | unsigned long __user *fp, *uregs; | |
233 | ||
234 | next_ip = regs->nip; | |
235 | lr = regs->link; | |
236 | sp = regs->gpr[1]; | |
70791ce9 FW |
237 | perf_callchain_store(entry, PERF_CONTEXT_USER); |
238 | perf_callchain_store(entry, next_ip); | |
20002ded PM |
239 | |
240 | for (;;) { | |
241 | fp = (unsigned long __user *) sp; | |
242 | if (!valid_user_sp(sp, 1) || read_user_stack_64(fp, &next_sp)) | |
243 | return; | |
244 | if (level > 0 && read_user_stack_64(&fp[2], &next_ip)) | |
245 | return; | |
246 | ||
247 | /* | |
248 | * Note: the next_sp - sp >= signal frame size check | |
249 | * is true when next_sp < sp, which can happen when | |
250 | * transitioning from an alternate signal stack to the | |
251 | * normal stack. | |
252 | */ | |
253 | if (next_sp - sp >= sizeof(struct signal_frame_64) && | |
254 | (is_sigreturn_64_address(next_ip, sp) || | |
255 | (level <= 1 && is_sigreturn_64_address(lr, sp))) && | |
256 | sane_signal_64_frame(sp)) { | |
257 | /* | |
258 | * This looks like an signal frame | |
259 | */ | |
260 | sigframe = (struct signal_frame_64 __user *) sp; | |
261 | uregs = sigframe->uc.uc_mcontext.gp_regs; | |
262 | if (read_user_stack_64(&uregs[PT_NIP], &next_ip) || | |
263 | read_user_stack_64(&uregs[PT_LNK], &lr) || | |
264 | read_user_stack_64(&uregs[PT_R1], &sp)) | |
265 | return; | |
266 | level = 0; | |
70791ce9 FW |
267 | perf_callchain_store(entry, PERF_CONTEXT_USER); |
268 | perf_callchain_store(entry, next_ip); | |
20002ded PM |
269 | continue; |
270 | } | |
271 | ||
272 | if (level == 0) | |
273 | next_ip = lr; | |
70791ce9 | 274 | perf_callchain_store(entry, next_ip); |
20002ded PM |
275 | ++level; |
276 | sp = next_sp; | |
277 | } | |
278 | } | |
279 | ||
280 | static inline int current_is_64bit(void) | |
281 | { | |
282 | /* | |
283 | * We can't use test_thread_flag() here because we may be on an | |
284 | * interrupt stack, and the thread flags don't get copied over | |
285 | * from the thread_info on the main stack to the interrupt stack. | |
286 | */ | |
287 | return !test_ti_thread_flag(task_thread_info(current), TIF_32BIT); | |
288 | } | |
289 | ||
290 | #else /* CONFIG_PPC64 */ | |
291 | /* | |
292 | * On 32-bit we just access the address and let hash_page create a | |
293 | * HPTE if necessary, so there is no need to fall back to reading | |
294 | * the page tables. Since this is called at interrupt level, | |
295 | * do_page_fault() won't treat a DSI as a page fault. | |
296 | */ | |
297 | static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret) | |
298 | { | |
299 | if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned int) || | |
300 | ((unsigned long)ptr & 3)) | |
301 | return -EFAULT; | |
302 | ||
303 | return __get_user_inatomic(*ret, ptr); | |
304 | } | |
305 | ||
306 | static inline void perf_callchain_user_64(struct pt_regs *regs, | |
307 | struct perf_callchain_entry *entry) | |
308 | { | |
309 | } | |
310 | ||
311 | static inline int current_is_64bit(void) | |
312 | { | |
313 | return 0; | |
314 | } | |
315 | ||
316 | static inline int valid_user_sp(unsigned long sp, int is_64) | |
317 | { | |
318 | if (!sp || (sp & 7) || sp > TASK_SIZE - 32) | |
319 | return 0; | |
320 | return 1; | |
321 | } | |
322 | ||
323 | #define __SIGNAL_FRAMESIZE32 __SIGNAL_FRAMESIZE | |
324 | #define sigcontext32 sigcontext | |
325 | #define mcontext32 mcontext | |
326 | #define ucontext32 ucontext | |
327 | #define compat_siginfo_t struct siginfo | |
328 | ||
329 | #endif /* CONFIG_PPC64 */ | |
330 | ||
331 | /* | |
332 | * Layout for non-RT signal frames | |
333 | */ | |
334 | struct signal_frame_32 { | |
335 | char dummy[__SIGNAL_FRAMESIZE32]; | |
336 | struct sigcontext32 sctx; | |
337 | struct mcontext32 mctx; | |
338 | int abigap[56]; | |
339 | }; | |
340 | ||
341 | /* | |
342 | * Layout for RT signal frames | |
343 | */ | |
344 | struct rt_signal_frame_32 { | |
345 | char dummy[__SIGNAL_FRAMESIZE32 + 16]; | |
346 | compat_siginfo_t info; | |
347 | struct ucontext32 uc; | |
348 | int abigap[56]; | |
349 | }; | |
350 | ||
351 | static int is_sigreturn_32_address(unsigned int nip, unsigned int fp) | |
352 | { | |
353 | if (nip == fp + offsetof(struct signal_frame_32, mctx.mc_pad)) | |
354 | return 1; | |
355 | if (vdso32_sigtramp && current->mm->context.vdso_base && | |
356 | nip == current->mm->context.vdso_base + vdso32_sigtramp) | |
357 | return 1; | |
358 | return 0; | |
359 | } | |
360 | ||
361 | static int is_rt_sigreturn_32_address(unsigned int nip, unsigned int fp) | |
362 | { | |
363 | if (nip == fp + offsetof(struct rt_signal_frame_32, | |
364 | uc.uc_mcontext.mc_pad)) | |
365 | return 1; | |
366 | if (vdso32_rt_sigtramp && current->mm->context.vdso_base && | |
367 | nip == current->mm->context.vdso_base + vdso32_rt_sigtramp) | |
368 | return 1; | |
369 | return 0; | |
370 | } | |
371 | ||
372 | static int sane_signal_32_frame(unsigned int sp) | |
373 | { | |
374 | struct signal_frame_32 __user *sf; | |
375 | unsigned int regs; | |
376 | ||
377 | sf = (struct signal_frame_32 __user *) (unsigned long) sp; | |
378 | if (read_user_stack_32((unsigned int __user *) &sf->sctx.regs, ®s)) | |
379 | return 0; | |
380 | return regs == (unsigned long) &sf->mctx; | |
381 | } | |
382 | ||
383 | static int sane_rt_signal_32_frame(unsigned int sp) | |
384 | { | |
385 | struct rt_signal_frame_32 __user *sf; | |
386 | unsigned int regs; | |
387 | ||
388 | sf = (struct rt_signal_frame_32 __user *) (unsigned long) sp; | |
389 | if (read_user_stack_32((unsigned int __user *) &sf->uc.uc_regs, ®s)) | |
390 | return 0; | |
391 | return regs == (unsigned long) &sf->uc.uc_mcontext; | |
392 | } | |
393 | ||
394 | static unsigned int __user *signal_frame_32_regs(unsigned int sp, | |
395 | unsigned int next_sp, unsigned int next_ip) | |
396 | { | |
397 | struct mcontext32 __user *mctx = NULL; | |
398 | struct signal_frame_32 __user *sf; | |
399 | struct rt_signal_frame_32 __user *rt_sf; | |
400 | ||
401 | /* | |
402 | * Note: the next_sp - sp >= signal frame size check | |
403 | * is true when next_sp < sp, for example, when | |
404 | * transitioning from an alternate signal stack to the | |
405 | * normal stack. | |
406 | */ | |
407 | if (next_sp - sp >= sizeof(struct signal_frame_32) && | |
408 | is_sigreturn_32_address(next_ip, sp) && | |
409 | sane_signal_32_frame(sp)) { | |
410 | sf = (struct signal_frame_32 __user *) (unsigned long) sp; | |
411 | mctx = &sf->mctx; | |
412 | } | |
413 | ||
414 | if (!mctx && next_sp - sp >= sizeof(struct rt_signal_frame_32) && | |
415 | is_rt_sigreturn_32_address(next_ip, sp) && | |
416 | sane_rt_signal_32_frame(sp)) { | |
417 | rt_sf = (struct rt_signal_frame_32 __user *) (unsigned long) sp; | |
418 | mctx = &rt_sf->uc.uc_mcontext; | |
419 | } | |
420 | ||
421 | if (!mctx) | |
422 | return NULL; | |
423 | return mctx->mc_gregs; | |
424 | } | |
425 | ||
426 | static void perf_callchain_user_32(struct pt_regs *regs, | |
427 | struct perf_callchain_entry *entry) | |
428 | { | |
429 | unsigned int sp, next_sp; | |
430 | unsigned int next_ip; | |
431 | unsigned int lr; | |
432 | long level = 0; | |
433 | unsigned int __user *fp, *uregs; | |
434 | ||
435 | next_ip = regs->nip; | |
436 | lr = regs->link; | |
437 | sp = regs->gpr[1]; | |
70791ce9 FW |
438 | perf_callchain_store(entry, PERF_CONTEXT_USER); |
439 | perf_callchain_store(entry, next_ip); | |
20002ded PM |
440 | |
441 | while (entry->nr < PERF_MAX_STACK_DEPTH) { | |
442 | fp = (unsigned int __user *) (unsigned long) sp; | |
443 | if (!valid_user_sp(sp, 0) || read_user_stack_32(fp, &next_sp)) | |
444 | return; | |
445 | if (level > 0 && read_user_stack_32(&fp[1], &next_ip)) | |
446 | return; | |
447 | ||
448 | uregs = signal_frame_32_regs(sp, next_sp, next_ip); | |
449 | if (!uregs && level <= 1) | |
450 | uregs = signal_frame_32_regs(sp, next_sp, lr); | |
451 | if (uregs) { | |
452 | /* | |
453 | * This looks like an signal frame, so restart | |
454 | * the stack trace with the values in it. | |
455 | */ | |
456 | if (read_user_stack_32(&uregs[PT_NIP], &next_ip) || | |
457 | read_user_stack_32(&uregs[PT_LNK], &lr) || | |
458 | read_user_stack_32(&uregs[PT_R1], &sp)) | |
459 | return; | |
460 | level = 0; | |
70791ce9 FW |
461 | perf_callchain_store(entry, PERF_CONTEXT_USER); |
462 | perf_callchain_store(entry, next_ip); | |
20002ded PM |
463 | continue; |
464 | } | |
465 | ||
466 | if (level == 0) | |
467 | next_ip = lr; | |
70791ce9 | 468 | perf_callchain_store(entry, next_ip); |
20002ded PM |
469 | ++level; |
470 | sp = next_sp; | |
471 | } | |
472 | } | |
473 | ||
474 | /* | |
475 | * Since we can't get PMU interrupts inside a PMU interrupt handler, | |
476 | * we don't need separate irq and nmi entries here. | |
477 | */ | |
6b7487fc | 478 | static DEFINE_PER_CPU(struct perf_callchain_entry, cpu_perf_callchain); |
20002ded PM |
479 | |
480 | struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) | |
481 | { | |
6b7487fc | 482 | struct perf_callchain_entry *entry = &__get_cpu_var(cpu_perf_callchain); |
20002ded PM |
483 | |
484 | entry->nr = 0; | |
485 | ||
20002ded PM |
486 | if (!user_mode(regs)) { |
487 | perf_callchain_kernel(regs, entry); | |
488 | if (current->mm) | |
489 | regs = task_pt_regs(current); | |
490 | else | |
491 | regs = NULL; | |
492 | } | |
493 | ||
494 | if (regs) { | |
495 | if (current_is_64bit()) | |
496 | perf_callchain_user_64(regs, entry); | |
497 | else | |
498 | perf_callchain_user_32(regs, entry); | |
499 | } | |
500 | ||
501 | return entry; | |
502 | } |