diff options
Diffstat (limited to 'arch/powerpc/kernel/perf_callchain.c')
-rw-r--r-- | arch/powerpc/kernel/perf_callchain.c | 527 |
1 files changed, 527 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/perf_callchain.c b/arch/powerpc/kernel/perf_callchain.c new file mode 100644 index 00000000000..f74b62c6751 --- /dev/null +++ b/arch/powerpc/kernel/perf_callchain.c | |||
@@ -0,0 +1,527 @@ | |||
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> | ||
13 | #include <linux/perf_counter.h> | ||
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 | |||
26 | /* | ||
27 | * Store another value in a callchain_entry. | ||
28 | */ | ||
29 | static inline void callchain_store(struct perf_callchain_entry *entry, u64 ip) | ||
30 | { | ||
31 | unsigned int nr = entry->nr; | ||
32 | |||
33 | if (nr < PERF_MAX_STACK_DEPTH) { | ||
34 | entry->ip[nr] = ip; | ||
35 | entry->nr = nr + 1; | ||
36 | } | ||
37 | } | ||
38 | |||
39 | /* | ||
40 | * Is sp valid as the address of the next kernel stack frame after prev_sp? | ||
41 | * The next frame may be in a different stack area but should not go | ||
42 | * back down in the same stack area. | ||
43 | */ | ||
44 | static int valid_next_sp(unsigned long sp, unsigned long prev_sp) | ||
45 | { | ||
46 | if (sp & 0xf) | ||
47 | return 0; /* must be 16-byte aligned */ | ||
48 | if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD)) | ||
49 | return 0; | ||
50 | if (sp >= prev_sp + STACK_FRAME_OVERHEAD) | ||
51 | return 1; | ||
52 | /* | ||
53 | * sp could decrease when we jump off an interrupt stack | ||
54 | * back to the regular process stack. | ||
55 | */ | ||
56 | if ((sp & ~(THREAD_SIZE - 1)) != (prev_sp & ~(THREAD_SIZE - 1))) | ||
57 | return 1; | ||
58 | return 0; | ||
59 | } | ||
60 | |||
61 | static void perf_callchain_kernel(struct pt_regs *regs, | ||
62 | struct perf_callchain_entry *entry) | ||
63 | { | ||
64 | unsigned long sp, next_sp; | ||
65 | unsigned long next_ip; | ||
66 | unsigned long lr; | ||
67 | long level = 0; | ||
68 | unsigned long *fp; | ||
69 | |||
70 | lr = regs->link; | ||
71 | sp = regs->gpr[1]; | ||
72 | callchain_store(entry, PERF_CONTEXT_KERNEL); | ||
73 | callchain_store(entry, regs->nip); | ||
74 | |||
75 | if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD)) | ||
76 | return; | ||
77 | |||
78 | for (;;) { | ||
79 | fp = (unsigned long *) sp; | ||
80 | next_sp = fp[0]; | ||
81 | |||
82 | if (next_sp == sp + STACK_INT_FRAME_SIZE && | ||
83 | fp[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) { | ||
84 | /* | ||
85 | * This looks like an interrupt frame for an | ||
86 | * interrupt that occurred in the kernel | ||
87 | */ | ||
88 | regs = (struct pt_regs *)(sp + STACK_FRAME_OVERHEAD); | ||
89 | next_ip = regs->nip; | ||
90 | lr = regs->link; | ||
91 | level = 0; | ||
92 | callchain_store(entry, PERF_CONTEXT_KERNEL); | ||
93 | |||
94 | } else { | ||
95 | if (level == 0) | ||
96 | next_ip = lr; | ||
97 | else | ||
98 | next_ip = fp[STACK_FRAME_LR_SAVE]; | ||
99 | |||
100 | /* | ||
101 | * We can't tell which of the first two addresses | ||
102 | * we get are valid, but we can filter out the | ||
103 | * obviously bogus ones here. We replace them | ||
104 | * with 0 rather than removing them entirely so | ||
105 | * that userspace can tell which is which. | ||
106 | */ | ||
107 | if ((level == 1 && next_ip == lr) || | ||
108 | (level <= 1 && !kernel_text_address(next_ip))) | ||
109 | next_ip = 0; | ||
110 | |||
111 | ++level; | ||
112 | } | ||
113 | |||
114 | callchain_store(entry, next_ip); | ||
115 | if (!valid_next_sp(next_sp, sp)) | ||
116 | return; | ||
117 | sp = next_sp; | ||
118 | } | ||
119 | } | ||
120 | |||
121 | #ifdef CONFIG_PPC64 | ||
122 | |||
123 | #ifdef CONFIG_HUGETLB_PAGE | ||
124 | #define is_huge_psize(pagesize) (HPAGE_SHIFT && mmu_huge_psizes[pagesize]) | ||
125 | #else | ||
126 | #define is_huge_psize(pagesize) 0 | ||
127 | #endif | ||
128 | |||
129 | /* | ||
130 | * On 64-bit we don't want to invoke hash_page on user addresses from | ||
131 | * interrupt context, so if the access faults, we read the page tables | ||
132 | * to find which page (if any) is mapped and access it directly. | ||
133 | */ | ||
134 | static int read_user_stack_slow(void __user *ptr, void *ret, int nb) | ||
135 | { | ||
136 | pgd_t *pgdir; | ||
137 | pte_t *ptep, pte; | ||
138 | int pagesize; | ||
139 | unsigned long addr = (unsigned long) ptr; | ||
140 | unsigned long offset; | ||
141 | unsigned long pfn; | ||
142 | void *kaddr; | ||
143 | |||
144 | pgdir = current->mm->pgd; | ||
145 | if (!pgdir) | ||
146 | return -EFAULT; | ||
147 | |||
148 | pagesize = get_slice_psize(current->mm, addr); | ||
149 | |||
150 | /* align address to page boundary */ | ||
151 | offset = addr & ((1ul << mmu_psize_defs[pagesize].shift) - 1); | ||
152 | addr -= offset; | ||
153 | |||
154 | if (is_huge_psize(pagesize)) | ||
155 | ptep = huge_pte_offset(current->mm, addr); | ||
156 | else | ||
157 | ptep = find_linux_pte(pgdir, addr); | ||
158 | |||
159 | if (ptep == NULL) | ||
160 | return -EFAULT; | ||
161 | pte = *ptep; | ||
162 | if (!pte_present(pte) || !(pte_val(pte) & _PAGE_USER)) | ||
163 | return -EFAULT; | ||
164 | pfn = pte_pfn(pte); | ||
165 | if (!page_is_ram(pfn)) | ||
166 | return -EFAULT; | ||
167 | |||
168 | /* no highmem to worry about here */ | ||
169 | kaddr = pfn_to_kaddr(pfn); | ||
170 | memcpy(ret, kaddr + offset, nb); | ||
171 | return 0; | ||
172 | } | ||
173 | |||
174 | static int read_user_stack_64(unsigned long __user *ptr, unsigned long *ret) | ||
175 | { | ||
176 | if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned long) || | ||
177 | ((unsigned long)ptr & 7)) | ||
178 | return -EFAULT; | ||
179 | |||
180 | if (!__get_user_inatomic(*ret, ptr)) | ||
181 | return 0; | ||
182 | |||
183 | return read_user_stack_slow(ptr, ret, 8); | ||
184 | } | ||
185 | |||
186 | static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret) | ||
187 | { | ||
188 | if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned int) || | ||
189 | ((unsigned long)ptr & 3)) | ||
190 | return -EFAULT; | ||
191 | |||
192 | if (!__get_user_inatomic(*ret, ptr)) | ||
193 | return 0; | ||
194 | |||
195 | return read_user_stack_slow(ptr, ret, 4); | ||
196 | } | ||
197 | |||
198 | static inline int valid_user_sp(unsigned long sp, int is_64) | ||
199 | { | ||
200 | if (!sp || (sp & 7) || sp > (is_64 ? TASK_SIZE : 0x100000000UL) - 32) | ||
201 | return 0; | ||
202 | return 1; | ||
203 | } | ||
204 | |||
205 | /* | ||
206 | * 64-bit user processes use the same stack frame for RT and non-RT signals. | ||
207 | */ | ||
208 | struct signal_frame_64 { | ||
209 | char dummy[__SIGNAL_FRAMESIZE]; | ||
210 | struct ucontext uc; | ||
211 | unsigned long unused[2]; | ||
212 | unsigned int tramp[6]; | ||
213 | struct siginfo *pinfo; | ||
214 | void *puc; | ||
215 | struct siginfo info; | ||
216 | char abigap[288]; | ||
217 | }; | ||
218 | |||
219 | static int is_sigreturn_64_address(unsigned long nip, unsigned long fp) | ||
220 | { | ||
221 | if (nip == fp + offsetof(struct signal_frame_64, tramp)) | ||
222 | return 1; | ||
223 | if (vdso64_rt_sigtramp && current->mm->context.vdso_base && | ||
224 | nip == current->mm->context.vdso_base + vdso64_rt_sigtramp) | ||
225 | return 1; | ||
226 | return 0; | ||
227 | } | ||
228 | |||
229 | /* | ||
230 | * Do some sanity checking on the signal frame pointed to by sp. | ||
231 | * We check the pinfo and puc pointers in the frame. | ||
232 | */ | ||
233 | static int sane_signal_64_frame(unsigned long sp) | ||
234 | { | ||
235 | struct signal_frame_64 __user *sf; | ||
236 | unsigned long pinfo, puc; | ||
237 | |||
238 | sf = (struct signal_frame_64 __user *) sp; | ||
239 | if (read_user_stack_64((unsigned long __user *) &sf->pinfo, &pinfo) || | ||
240 | read_user_stack_64((unsigned long __user *) &sf->puc, &puc)) | ||
241 | return 0; | ||
242 | return pinfo == (unsigned long) &sf->info && | ||
243 | puc == (unsigned long) &sf->uc; | ||
244 | } | ||
245 | |||
246 | static void perf_callchain_user_64(struct pt_regs *regs, | ||
247 | struct perf_callchain_entry *entry) | ||
248 | { | ||
249 | unsigned long sp, next_sp; | ||
250 | unsigned long next_ip; | ||
251 | unsigned long lr; | ||
252 | long level = 0; | ||
253 | struct signal_frame_64 __user *sigframe; | ||
254 | unsigned long __user *fp, *uregs; | ||
255 | |||
256 | next_ip = regs->nip; | ||
257 | lr = regs->link; | ||
258 | sp = regs->gpr[1]; | ||
259 | callchain_store(entry, PERF_CONTEXT_USER); | ||
260 | callchain_store(entry, next_ip); | ||
261 | |||
262 | for (;;) { | ||
263 | fp = (unsigned long __user *) sp; | ||
264 | if (!valid_user_sp(sp, 1) || read_user_stack_64(fp, &next_sp)) | ||
265 | return; | ||
266 | if (level > 0 && read_user_stack_64(&fp[2], &next_ip)) | ||
267 | return; | ||
268 | |||
269 | /* | ||
270 | * Note: the next_sp - sp >= signal frame size check | ||
271 | * is true when next_sp < sp, which can happen when | ||
272 | * transitioning from an alternate signal stack to the | ||
273 | * normal stack. | ||
274 | */ | ||
275 | if (next_sp - sp >= sizeof(struct signal_frame_64) && | ||
276 | (is_sigreturn_64_address(next_ip, sp) || | ||
277 | (level <= 1 && is_sigreturn_64_address(lr, sp))) && | ||
278 | sane_signal_64_frame(sp)) { | ||
279 | /* | ||
280 | * This looks like an signal frame | ||
281 | */ | ||
282 | sigframe = (struct signal_frame_64 __user *) sp; | ||
283 | uregs = sigframe->uc.uc_mcontext.gp_regs; | ||
284 | if (read_user_stack_64(&uregs[PT_NIP], &next_ip) || | ||
285 | read_user_stack_64(&uregs[PT_LNK], &lr) || | ||
286 | read_user_stack_64(&uregs[PT_R1], &sp)) | ||
287 | return; | ||
288 | level = 0; | ||
289 | callchain_store(entry, PERF_CONTEXT_USER); | ||
290 | callchain_store(entry, next_ip); | ||
291 | continue; | ||
292 | } | ||
293 | |||
294 | if (level == 0) | ||
295 | next_ip = lr; | ||
296 | callchain_store(entry, next_ip); | ||
297 | ++level; | ||
298 | sp = next_sp; | ||
299 | } | ||
300 | } | ||
301 | |||
302 | static inline int current_is_64bit(void) | ||
303 | { | ||
304 | /* | ||
305 | * We can't use test_thread_flag() here because we may be on an | ||
306 | * interrupt stack, and the thread flags don't get copied over | ||
307 | * from the thread_info on the main stack to the interrupt stack. | ||
308 | */ | ||
309 | return !test_ti_thread_flag(task_thread_info(current), TIF_32BIT); | ||
310 | } | ||
311 | |||
312 | #else /* CONFIG_PPC64 */ | ||
313 | /* | ||
314 | * On 32-bit we just access the address and let hash_page create a | ||
315 | * HPTE if necessary, so there is no need to fall back to reading | ||
316 | * the page tables. Since this is called at interrupt level, | ||
317 | * do_page_fault() won't treat a DSI as a page fault. | ||
318 | */ | ||
319 | static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret) | ||
320 | { | ||
321 | if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned int) || | ||
322 | ((unsigned long)ptr & 3)) | ||
323 | return -EFAULT; | ||
324 | |||
325 | return __get_user_inatomic(*ret, ptr); | ||
326 | } | ||
327 | |||
328 | static inline void perf_callchain_user_64(struct pt_regs *regs, | ||
329 | struct perf_callchain_entry *entry) | ||
330 | { | ||
331 | } | ||
332 | |||
333 | static inline int current_is_64bit(void) | ||
334 | { | ||
335 | return 0; | ||
336 | } | ||
337 | |||
338 | static inline int valid_user_sp(unsigned long sp, int is_64) | ||
339 | { | ||
340 | if (!sp || (sp & 7) || sp > TASK_SIZE - 32) | ||
341 | return 0; | ||
342 | return 1; | ||
343 | } | ||
344 | |||
345 | #define __SIGNAL_FRAMESIZE32 __SIGNAL_FRAMESIZE | ||
346 | #define sigcontext32 sigcontext | ||
347 | #define mcontext32 mcontext | ||
348 | #define ucontext32 ucontext | ||
349 | #define compat_siginfo_t struct siginfo | ||
350 | |||
351 | #endif /* CONFIG_PPC64 */ | ||
352 | |||
353 | /* | ||
354 | * Layout for non-RT signal frames | ||
355 | */ | ||
356 | struct signal_frame_32 { | ||
357 | char dummy[__SIGNAL_FRAMESIZE32]; | ||
358 | struct sigcontext32 sctx; | ||
359 | struct mcontext32 mctx; | ||
360 | int abigap[56]; | ||
361 | }; | ||
362 | |||
363 | /* | ||
364 | * Layout for RT signal frames | ||
365 | */ | ||
366 | struct rt_signal_frame_32 { | ||
367 | char dummy[__SIGNAL_FRAMESIZE32 + 16]; | ||
368 | compat_siginfo_t info; | ||
369 | struct ucontext32 uc; | ||
370 | int abigap[56]; | ||
371 | }; | ||
372 | |||
373 | static int is_sigreturn_32_address(unsigned int nip, unsigned int fp) | ||
374 | { | ||
375 | if (nip == fp + offsetof(struct signal_frame_32, mctx.mc_pad)) | ||
376 | return 1; | ||
377 | if (vdso32_sigtramp && current->mm->context.vdso_base && | ||
378 | nip == current->mm->context.vdso_base + vdso32_sigtramp) | ||
379 | return 1; | ||
380 | return 0; | ||
381 | } | ||
382 | |||
383 | static int is_rt_sigreturn_32_address(unsigned int nip, unsigned int fp) | ||
384 | { | ||
385 | if (nip == fp + offsetof(struct rt_signal_frame_32, | ||
386 | uc.uc_mcontext.mc_pad)) | ||
387 | return 1; | ||
388 | if (vdso32_rt_sigtramp && current->mm->context.vdso_base && | ||
389 | nip == current->mm->context.vdso_base + vdso32_rt_sigtramp) | ||
390 | return 1; | ||
391 | return 0; | ||
392 | } | ||
393 | |||
394 | static int sane_signal_32_frame(unsigned int sp) | ||
395 | { | ||
396 | struct signal_frame_32 __user *sf; | ||
397 | unsigned int regs; | ||
398 | |||
399 | sf = (struct signal_frame_32 __user *) (unsigned long) sp; | ||
400 | if (read_user_stack_32((unsigned int __user *) &sf->sctx.regs, ®s)) | ||
401 | return 0; | ||
402 | return regs == (unsigned long) &sf->mctx; | ||
403 | } | ||
404 | |||
405 | static int sane_rt_signal_32_frame(unsigned int sp) | ||
406 | { | ||
407 | struct rt_signal_frame_32 __user *sf; | ||
408 | unsigned int regs; | ||
409 | |||
410 | sf = (struct rt_signal_frame_32 __user *) (unsigned long) sp; | ||
411 | if (read_user_stack_32((unsigned int __user *) &sf->uc.uc_regs, ®s)) | ||
412 | return 0; | ||
413 | return regs == (unsigned long) &sf->uc.uc_mcontext; | ||
414 | } | ||
415 | |||
416 | static unsigned int __user *signal_frame_32_regs(unsigned int sp, | ||
417 | unsigned int next_sp, unsigned int next_ip) | ||
418 | { | ||
419 | struct mcontext32 __user *mctx = NULL; | ||
420 | struct signal_frame_32 __user *sf; | ||
421 | struct rt_signal_frame_32 __user *rt_sf; | ||
422 | |||
423 | /* | ||
424 | * Note: the next_sp - sp >= signal frame size check | ||
425 | * is true when next_sp < sp, for example, when | ||
426 | * transitioning from an alternate signal stack to the | ||
427 | * normal stack. | ||
428 | */ | ||
429 | if (next_sp - sp >= sizeof(struct signal_frame_32) && | ||
430 | is_sigreturn_32_address(next_ip, sp) && | ||
431 | sane_signal_32_frame(sp)) { | ||
432 | sf = (struct signal_frame_32 __user *) (unsigned long) sp; | ||
433 | mctx = &sf->mctx; | ||
434 | } | ||
435 | |||
436 | if (!mctx && next_sp - sp >= sizeof(struct rt_signal_frame_32) && | ||
437 | is_rt_sigreturn_32_address(next_ip, sp) && | ||
438 | sane_rt_signal_32_frame(sp)) { | ||
439 | rt_sf = (struct rt_signal_frame_32 __user *) (unsigned long) sp; | ||
440 | mctx = &rt_sf->uc.uc_mcontext; | ||
441 | } | ||
442 | |||
443 | if (!mctx) | ||
444 | return NULL; | ||
445 | return mctx->mc_gregs; | ||
446 | } | ||
447 | |||
448 | static void perf_callchain_user_32(struct pt_regs *regs, | ||
449 | struct perf_callchain_entry *entry) | ||
450 | { | ||
451 | unsigned int sp, next_sp; | ||
452 | unsigned int next_ip; | ||
453 | unsigned int lr; | ||
454 | long level = 0; | ||
455 | unsigned int __user *fp, *uregs; | ||
456 | |||
457 | next_ip = regs->nip; | ||
458 | lr = regs->link; | ||
459 | sp = regs->gpr[1]; | ||
460 | callchain_store(entry, PERF_CONTEXT_USER); | ||
461 | callchain_store(entry, next_ip); | ||
462 | |||
463 | while (entry->nr < PERF_MAX_STACK_DEPTH) { | ||
464 | fp = (unsigned int __user *) (unsigned long) sp; | ||
465 | if (!valid_user_sp(sp, 0) || read_user_stack_32(fp, &next_sp)) | ||
466 | return; | ||
467 | if (level > 0 && read_user_stack_32(&fp[1], &next_ip)) | ||
468 | return; | ||
469 | |||
470 | uregs = signal_frame_32_regs(sp, next_sp, next_ip); | ||
471 | if (!uregs && level <= 1) | ||
472 | uregs = signal_frame_32_regs(sp, next_sp, lr); | ||
473 | if (uregs) { | ||
474 | /* | ||
475 | * This looks like an signal frame, so restart | ||
476 | * the stack trace with the values in it. | ||
477 | */ | ||
478 | if (read_user_stack_32(&uregs[PT_NIP], &next_ip) || | ||
479 | read_user_stack_32(&uregs[PT_LNK], &lr) || | ||
480 | read_user_stack_32(&uregs[PT_R1], &sp)) | ||
481 | return; | ||
482 | level = 0; | ||
483 | callchain_store(entry, PERF_CONTEXT_USER); | ||
484 | callchain_store(entry, next_ip); | ||
485 | continue; | ||
486 | } | ||
487 | |||
488 | if (level == 0) | ||
489 | next_ip = lr; | ||
490 | callchain_store(entry, next_ip); | ||
491 | ++level; | ||
492 | sp = next_sp; | ||
493 | } | ||
494 | } | ||
495 | |||
496 | /* | ||
497 | * Since we can't get PMU interrupts inside a PMU interrupt handler, | ||
498 | * we don't need separate irq and nmi entries here. | ||
499 | */ | ||
500 | static DEFINE_PER_CPU(struct perf_callchain_entry, callchain); | ||
501 | |||
502 | struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) | ||
503 | { | ||
504 | struct perf_callchain_entry *entry = &__get_cpu_var(callchain); | ||
505 | |||
506 | entry->nr = 0; | ||
507 | |||
508 | if (current->pid == 0) /* idle task? */ | ||
509 | return entry; | ||
510 | |||
511 | if (!user_mode(regs)) { | ||
512 | perf_callchain_kernel(regs, entry); | ||
513 | if (current->mm) | ||
514 | regs = task_pt_regs(current); | ||
515 | else | ||
516 | regs = NULL; | ||
517 | } | ||
518 | |||
519 | if (regs) { | ||
520 | if (current_is_64bit()) | ||
521 | perf_callchain_user_64(regs, entry); | ||
522 | else | ||
523 | perf_callchain_user_32(regs, entry); | ||
524 | } | ||
525 | |||
526 | return entry; | ||
527 | } | ||