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25763b3c | 1 | // SPDX-License-Identifier: GPL-2.0-only |
d5a3b1f6 | 2 | /* Copyright (c) 2016 Facebook |
d5a3b1f6 AS |
3 | */ |
4 | #include <linux/bpf.h> | |
5 | #include <linux/jhash.h> | |
6 | #include <linux/filter.h> | |
7b04d6d6 | 7 | #include <linux/kernel.h> |
d5a3b1f6 AS |
8 | #include <linux/stacktrace.h> |
9 | #include <linux/perf_event.h> | |
c9a0f3b8 | 10 | #include <linux/btf_ids.h> |
bd7525da | 11 | #include <linux/buildid.h> |
557c0c6e | 12 | #include "percpu_freelist.h" |
7c7e3d31 | 13 | #include "mmap_unlock_work.h" |
d5a3b1f6 | 14 | |
615755a7 SL |
15 | #define STACK_CREATE_FLAG_MASK \ |
16 | (BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY | \ | |
17 | BPF_F_STACK_BUILD_ID) | |
6e71b04a | 18 | |
d5a3b1f6 | 19 | struct stack_map_bucket { |
557c0c6e | 20 | struct pcpu_freelist_node fnode; |
d5a3b1f6 AS |
21 | u32 hash; |
22 | u32 nr; | |
615755a7 | 23 | u64 data[]; |
d5a3b1f6 AS |
24 | }; |
25 | ||
26 | struct bpf_stack_map { | |
27 | struct bpf_map map; | |
557c0c6e AS |
28 | void *elems; |
29 | struct pcpu_freelist freelist; | |
d5a3b1f6 | 30 | u32 n_buckets; |
557c0c6e | 31 | struct stack_map_bucket *buckets[]; |
d5a3b1f6 AS |
32 | }; |
33 | ||
615755a7 SL |
34 | static inline bool stack_map_use_build_id(struct bpf_map *map) |
35 | { | |
36 | return (map->map_flags & BPF_F_STACK_BUILD_ID); | |
37 | } | |
38 | ||
39 | static inline int stack_map_data_size(struct bpf_map *map) | |
40 | { | |
41 | return stack_map_use_build_id(map) ? | |
42 | sizeof(struct bpf_stack_build_id) : sizeof(u64); | |
43 | } | |
44 | ||
557c0c6e AS |
45 | static int prealloc_elems_and_freelist(struct bpf_stack_map *smap) |
46 | { | |
30e29a9a TY |
47 | u64 elem_size = sizeof(struct stack_map_bucket) + |
48 | (u64)smap->map.value_size; | |
557c0c6e AS |
49 | int err; |
50 | ||
96eabe7a MKL |
51 | smap->elems = bpf_map_area_alloc(elem_size * smap->map.max_entries, |
52 | smap->map.numa_node); | |
557c0c6e AS |
53 | if (!smap->elems) |
54 | return -ENOMEM; | |
55 | ||
56 | err = pcpu_freelist_init(&smap->freelist); | |
57 | if (err) | |
58 | goto free_elems; | |
59 | ||
60 | pcpu_freelist_populate(&smap->freelist, smap->elems, elem_size, | |
61 | smap->map.max_entries); | |
62 | return 0; | |
63 | ||
64 | free_elems: | |
d407bd25 | 65 | bpf_map_area_free(smap->elems); |
557c0c6e AS |
66 | return err; |
67 | } | |
68 | ||
d5a3b1f6 AS |
69 | /* Called from syscall */ |
70 | static struct bpf_map *stack_map_alloc(union bpf_attr *attr) | |
71 | { | |
72 | u32 value_size = attr->value_size; | |
73 | struct bpf_stack_map *smap; | |
74 | u64 cost, n_buckets; | |
75 | int err; | |
76 | ||
6e71b04a | 77 | if (attr->map_flags & ~STACK_CREATE_FLAG_MASK) |
823707b6 AS |
78 | return ERR_PTR(-EINVAL); |
79 | ||
d5a3b1f6 AS |
80 | /* check sanity of attributes */ |
81 | if (attr->max_entries == 0 || attr->key_size != 4 || | |
615755a7 SL |
82 | value_size < 8 || value_size % 8) |
83 | return ERR_PTR(-EINVAL); | |
84 | ||
85 | BUILD_BUG_ON(sizeof(struct bpf_stack_build_id) % sizeof(u64)); | |
86 | if (attr->map_flags & BPF_F_STACK_BUILD_ID) { | |
87 | if (value_size % sizeof(struct bpf_stack_build_id) || | |
88 | value_size / sizeof(struct bpf_stack_build_id) | |
89 | > sysctl_perf_event_max_stack) | |
90 | return ERR_PTR(-EINVAL); | |
91 | } else if (value_size / 8 > sysctl_perf_event_max_stack) | |
d5a3b1f6 AS |
92 | return ERR_PTR(-EINVAL); |
93 | ||
94 | /* hash table size must be power of 2 */ | |
95 | n_buckets = roundup_pow_of_two(attr->max_entries); | |
6183f4d3 BQM |
96 | if (!n_buckets) |
97 | return ERR_PTR(-E2BIG); | |
d5a3b1f6 AS |
98 | |
99 | cost = n_buckets * sizeof(struct stack_map_bucket *) + sizeof(*smap); | |
96eabe7a | 100 | smap = bpf_map_area_alloc(cost, bpf_map_attr_numa_node(attr)); |
37086810 | 101 | if (!smap) |
d407bd25 | 102 | return ERR_PTR(-ENOMEM); |
d5a3b1f6 | 103 | |
bd475643 | 104 | bpf_map_init_from_attr(&smap->map, attr); |
d5a3b1f6 | 105 | smap->n_buckets = n_buckets; |
557c0c6e | 106 | |
97c79a38 | 107 | err = get_callchain_buffers(sysctl_perf_event_max_stack); |
d5a3b1f6 | 108 | if (err) |
37086810 | 109 | goto free_smap; |
d5a3b1f6 | 110 | |
557c0c6e AS |
111 | err = prealloc_elems_and_freelist(smap); |
112 | if (err) | |
113 | goto put_buffers; | |
114 | ||
d5a3b1f6 AS |
115 | return &smap->map; |
116 | ||
557c0c6e AS |
117 | put_buffers: |
118 | put_callchain_buffers(); | |
37086810 | 119 | free_smap: |
d407bd25 | 120 | bpf_map_area_free(smap); |
d5a3b1f6 AS |
121 | return ERR_PTR(err); |
122 | } | |
123 | ||
5f412632 | 124 | static void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs, |
615755a7 SL |
125 | u64 *ips, u32 trace_nr, bool user) |
126 | { | |
127 | int i; | |
7c7e3d31 SL |
128 | struct mmap_unlock_irq_work *work = NULL; |
129 | bool irq_work_busy = bpf_mmap_unlock_get_irq_work(&work); | |
ceac059e HL |
130 | struct vm_area_struct *vma, *prev_vma = NULL; |
131 | const char *prev_build_id; | |
615755a7 | 132 | |
7c7e3d31 SL |
133 | /* If the irq_work is in use, fall back to report ips. Same |
134 | * fallback is used for kernel stack (!user) on a stackmap with | |
135 | * build_id. | |
615755a7 | 136 | */ |
bae77c5e | 137 | if (!user || !current || !current->mm || irq_work_busy || |
2f1aaf3e | 138 | !mmap_read_trylock(current->mm)) { |
615755a7 SL |
139 | /* cannot access current->mm, fall back to ips */ |
140 | for (i = 0; i < trace_nr; i++) { | |
141 | id_offs[i].status = BPF_STACK_BUILD_ID_IP; | |
142 | id_offs[i].ip = ips[i]; | |
bd7525da | 143 | memset(id_offs[i].build_id, 0, BUILD_ID_SIZE_MAX); |
615755a7 SL |
144 | } |
145 | return; | |
146 | } | |
147 | ||
148 | for (i = 0; i < trace_nr; i++) { | |
ceac059e HL |
149 | if (range_in_vma(prev_vma, ips[i], ips[i])) { |
150 | vma = prev_vma; | |
151 | memcpy(id_offs[i].build_id, prev_build_id, | |
152 | BUILD_ID_SIZE_MAX); | |
153 | goto build_id_valid; | |
154 | } | |
615755a7 | 155 | vma = find_vma(current->mm, ips[i]); |
921f88fc | 156 | if (!vma || build_id_parse(vma, id_offs[i].build_id, NULL)) { |
615755a7 SL |
157 | /* per entry fall back to ips */ |
158 | id_offs[i].status = BPF_STACK_BUILD_ID_IP; | |
159 | id_offs[i].ip = ips[i]; | |
bd7525da | 160 | memset(id_offs[i].build_id, 0, BUILD_ID_SIZE_MAX); |
615755a7 SL |
161 | continue; |
162 | } | |
ceac059e | 163 | build_id_valid: |
615755a7 SL |
164 | id_offs[i].offset = (vma->vm_pgoff << PAGE_SHIFT) + ips[i] |
165 | - vma->vm_start; | |
166 | id_offs[i].status = BPF_STACK_BUILD_ID_VALID; | |
ceac059e HL |
167 | prev_vma = vma; |
168 | prev_build_id = id_offs[i].build_id; | |
615755a7 | 169 | } |
7c7e3d31 | 170 | bpf_mmap_unlock_mm(work, current->mm); |
615755a7 SL |
171 | } |
172 | ||
fa28dcb8 | 173 | static struct perf_callchain_entry * |
ee2a0988 | 174 | get_callchain_entry_for_task(struct task_struct *task, u32 max_depth) |
fa28dcb8 | 175 | { |
046cc3dd | 176 | #ifdef CONFIG_STACKTRACE |
fa28dcb8 SL |
177 | struct perf_callchain_entry *entry; |
178 | int rctx; | |
179 | ||
180 | entry = get_callchain_entry(&rctx); | |
181 | ||
182 | if (!entry) | |
183 | return NULL; | |
184 | ||
ee2a0988 NK |
185 | entry->nr = stack_trace_save_tsk(task, (unsigned long *)entry->ip, |
186 | max_depth, 0); | |
fa28dcb8 SL |
187 | |
188 | /* stack_trace_save_tsk() works on unsigned long array, while | |
189 | * perf_callchain_entry uses u64 array. For 32-bit systems, it is | |
190 | * necessary to fix this mismatch. | |
191 | */ | |
192 | if (__BITS_PER_LONG != 64) { | |
193 | unsigned long *from = (unsigned long *) entry->ip; | |
194 | u64 *to = entry->ip; | |
195 | int i; | |
196 | ||
197 | /* copy data from the end to avoid using extra buffer */ | |
ee2a0988 | 198 | for (i = entry->nr - 1; i >= 0; i--) |
fa28dcb8 SL |
199 | to[i] = (u64)(from[i]); |
200 | } | |
201 | ||
202 | put_callchain_entry(rctx); | |
203 | ||
204 | return entry; | |
046cc3dd SL |
205 | #else /* CONFIG_STACKTRACE */ |
206 | return NULL; | |
207 | #endif | |
fa28dcb8 SL |
208 | } |
209 | ||
7b04d6d6 SL |
210 | static long __bpf_get_stackid(struct bpf_map *map, |
211 | struct perf_callchain_entry *trace, u64 flags) | |
d5a3b1f6 | 212 | { |
d5a3b1f6 | 213 | struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); |
d5a3b1f6 | 214 | struct stack_map_bucket *bucket, *new_bucket, *old_bucket; |
d5a3b1f6 AS |
215 | u32 skip = flags & BPF_F_SKIP_FIELD_MASK; |
216 | u32 hash, id, trace_nr, trace_len; | |
217 | bool user = flags & BPF_F_USER_STACK; | |
d5a3b1f6 | 218 | u64 *ips; |
615755a7 | 219 | bool hash_matches; |
d5a3b1f6 | 220 | |
ee2a0988 | 221 | if (trace->nr <= skip) |
d5a3b1f6 AS |
222 | /* skipping more than usable stack trace */ |
223 | return -EFAULT; | |
224 | ||
ee2a0988 | 225 | trace_nr = trace->nr - skip; |
d5a3b1f6 | 226 | trace_len = trace_nr * sizeof(u64); |
ee2a0988 | 227 | ips = trace->ip + skip; |
d5a3b1f6 AS |
228 | hash = jhash2((u32 *)ips, trace_len / sizeof(u32), 0); |
229 | id = hash & (smap->n_buckets - 1); | |
557c0c6e | 230 | bucket = READ_ONCE(smap->buckets[id]); |
d5a3b1f6 | 231 | |
615755a7 SL |
232 | hash_matches = bucket && bucket->hash == hash; |
233 | /* fast cmp */ | |
234 | if (hash_matches && flags & BPF_F_FAST_STACK_CMP) | |
235 | return id; | |
236 | ||
237 | if (stack_map_use_build_id(map)) { | |
238 | /* for build_id+offset, pop a bucket before slow cmp */ | |
239 | new_bucket = (struct stack_map_bucket *) | |
240 | pcpu_freelist_pop(&smap->freelist); | |
241 | if (unlikely(!new_bucket)) | |
242 | return -ENOMEM; | |
5f412632 YS |
243 | new_bucket->nr = trace_nr; |
244 | stack_map_get_build_id_offset( | |
245 | (struct bpf_stack_build_id *)new_bucket->data, | |
246 | ips, trace_nr, user); | |
615755a7 SL |
247 | trace_len = trace_nr * sizeof(struct bpf_stack_build_id); |
248 | if (hash_matches && bucket->nr == trace_nr && | |
249 | memcmp(bucket->data, new_bucket->data, trace_len) == 0) { | |
250 | pcpu_freelist_push(&smap->freelist, &new_bucket->fnode); | |
d5a3b1f6 | 251 | return id; |
615755a7 SL |
252 | } |
253 | if (bucket && !(flags & BPF_F_REUSE_STACKID)) { | |
254 | pcpu_freelist_push(&smap->freelist, &new_bucket->fnode); | |
255 | return -EEXIST; | |
256 | } | |
257 | } else { | |
258 | if (hash_matches && bucket->nr == trace_nr && | |
259 | memcmp(bucket->data, ips, trace_len) == 0) | |
d5a3b1f6 | 260 | return id; |
615755a7 SL |
261 | if (bucket && !(flags & BPF_F_REUSE_STACKID)) |
262 | return -EEXIST; | |
263 | ||
264 | new_bucket = (struct stack_map_bucket *) | |
265 | pcpu_freelist_pop(&smap->freelist); | |
266 | if (unlikely(!new_bucket)) | |
267 | return -ENOMEM; | |
268 | memcpy(new_bucket->data, ips, trace_len); | |
d5a3b1f6 AS |
269 | } |
270 | ||
d5a3b1f6 AS |
271 | new_bucket->hash = hash; |
272 | new_bucket->nr = trace_nr; | |
273 | ||
274 | old_bucket = xchg(&smap->buckets[id], new_bucket); | |
275 | if (old_bucket) | |
557c0c6e | 276 | pcpu_freelist_push(&smap->freelist, &old_bucket->fnode); |
d5a3b1f6 AS |
277 | return id; |
278 | } | |
279 | ||
7b04d6d6 SL |
280 | BPF_CALL_3(bpf_get_stackid, struct pt_regs *, regs, struct bpf_map *, map, |
281 | u64, flags) | |
282 | { | |
283 | u32 max_depth = map->value_size / stack_map_data_size(map); | |
ee2a0988 | 284 | u32 skip = flags & BPF_F_SKIP_FIELD_MASK; |
7b04d6d6 SL |
285 | bool user = flags & BPF_F_USER_STACK; |
286 | struct perf_callchain_entry *trace; | |
287 | bool kernel = !user; | |
288 | ||
289 | if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK | | |
290 | BPF_F_FAST_STACK_CMP | BPF_F_REUSE_STACKID))) | |
291 | return -EINVAL; | |
292 | ||
ee2a0988 NK |
293 | max_depth += skip; |
294 | if (max_depth > sysctl_perf_event_max_stack) | |
295 | max_depth = sysctl_perf_event_max_stack; | |
296 | ||
297 | trace = get_perf_callchain(regs, 0, kernel, user, max_depth, | |
298 | false, false); | |
7b04d6d6 SL |
299 | |
300 | if (unlikely(!trace)) | |
301 | /* couldn't fetch the stack trace */ | |
302 | return -EFAULT; | |
303 | ||
304 | return __bpf_get_stackid(map, trace, flags); | |
305 | } | |
306 | ||
d5a3b1f6 AS |
307 | const struct bpf_func_proto bpf_get_stackid_proto = { |
308 | .func = bpf_get_stackid, | |
309 | .gpl_only = true, | |
310 | .ret_type = RET_INTEGER, | |
311 | .arg1_type = ARG_PTR_TO_CTX, | |
312 | .arg2_type = ARG_CONST_MAP_PTR, | |
313 | .arg3_type = ARG_ANYTHING, | |
314 | }; | |
315 | ||
7b04d6d6 SL |
316 | static __u64 count_kernel_ip(struct perf_callchain_entry *trace) |
317 | { | |
318 | __u64 nr_kernel = 0; | |
319 | ||
320 | while (nr_kernel < trace->nr) { | |
321 | if (trace->ip[nr_kernel] == PERF_CONTEXT_USER) | |
322 | break; | |
323 | nr_kernel++; | |
324 | } | |
325 | return nr_kernel; | |
326 | } | |
327 | ||
328 | BPF_CALL_3(bpf_get_stackid_pe, struct bpf_perf_event_data_kern *, ctx, | |
329 | struct bpf_map *, map, u64, flags) | |
330 | { | |
331 | struct perf_event *event = ctx->event; | |
332 | struct perf_callchain_entry *trace; | |
333 | bool kernel, user; | |
334 | __u64 nr_kernel; | |
335 | int ret; | |
336 | ||
337 | /* perf_sample_data doesn't have callchain, use bpf_get_stackid */ | |
16817ad7 | 338 | if (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)) |
7b04d6d6 SL |
339 | return bpf_get_stackid((unsigned long)(ctx->regs), |
340 | (unsigned long) map, flags, 0, 0); | |
341 | ||
342 | if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK | | |
343 | BPF_F_FAST_STACK_CMP | BPF_F_REUSE_STACKID))) | |
344 | return -EINVAL; | |
345 | ||
346 | user = flags & BPF_F_USER_STACK; | |
347 | kernel = !user; | |
348 | ||
349 | trace = ctx->data->callchain; | |
350 | if (unlikely(!trace)) | |
351 | return -EFAULT; | |
352 | ||
353 | nr_kernel = count_kernel_ip(trace); | |
354 | ||
355 | if (kernel) { | |
356 | __u64 nr = trace->nr; | |
357 | ||
358 | trace->nr = nr_kernel; | |
359 | ret = __bpf_get_stackid(map, trace, flags); | |
360 | ||
361 | /* restore nr */ | |
362 | trace->nr = nr; | |
363 | } else { /* user */ | |
364 | u64 skip = flags & BPF_F_SKIP_FIELD_MASK; | |
365 | ||
366 | skip += nr_kernel; | |
367 | if (skip > BPF_F_SKIP_FIELD_MASK) | |
368 | return -EFAULT; | |
369 | ||
370 | flags = (flags & ~BPF_F_SKIP_FIELD_MASK) | skip; | |
371 | ret = __bpf_get_stackid(map, trace, flags); | |
372 | } | |
373 | return ret; | |
374 | } | |
375 | ||
376 | const struct bpf_func_proto bpf_get_stackid_proto_pe = { | |
377 | .func = bpf_get_stackid_pe, | |
378 | .gpl_only = false, | |
379 | .ret_type = RET_INTEGER, | |
380 | .arg1_type = ARG_PTR_TO_CTX, | |
381 | .arg2_type = ARG_CONST_MAP_PTR, | |
382 | .arg3_type = ARG_ANYTHING, | |
383 | }; | |
384 | ||
fa28dcb8 | 385 | static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task, |
7b04d6d6 | 386 | struct perf_callchain_entry *trace_in, |
fa28dcb8 | 387 | void *buf, u32 size, u64 flags) |
c195651e | 388 | { |
ee2a0988 | 389 | u32 trace_nr, copy_len, elem_size, num_elem, max_depth; |
c195651e YS |
390 | bool user_build_id = flags & BPF_F_USER_BUILD_ID; |
391 | u32 skip = flags & BPF_F_SKIP_FIELD_MASK; | |
392 | bool user = flags & BPF_F_USER_STACK; | |
393 | struct perf_callchain_entry *trace; | |
394 | bool kernel = !user; | |
395 | int err = -EINVAL; | |
396 | u64 *ips; | |
397 | ||
398 | if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK | | |
399 | BPF_F_USER_BUILD_ID))) | |
400 | goto clear; | |
401 | if (kernel && user_build_id) | |
402 | goto clear; | |
403 | ||
404 | elem_size = (user && user_build_id) ? sizeof(struct bpf_stack_build_id) | |
405 | : sizeof(u64); | |
406 | if (unlikely(size % elem_size)) | |
407 | goto clear; | |
408 | ||
fa28dcb8 SL |
409 | /* cannot get valid user stack for task without user_mode regs */ |
410 | if (task && user && !user_mode(regs)) | |
411 | goto err_fault; | |
412 | ||
c195651e | 413 | num_elem = size / elem_size; |
ee2a0988 NK |
414 | max_depth = num_elem + skip; |
415 | if (sysctl_perf_event_max_stack < max_depth) | |
416 | max_depth = sysctl_perf_event_max_stack; | |
fa28dcb8 | 417 | |
7b04d6d6 SL |
418 | if (trace_in) |
419 | trace = trace_in; | |
420 | else if (kernel && task) | |
ee2a0988 | 421 | trace = get_callchain_entry_for_task(task, max_depth); |
fa28dcb8 | 422 | else |
ee2a0988 | 423 | trace = get_perf_callchain(regs, 0, kernel, user, max_depth, |
fa28dcb8 | 424 | false, false); |
c195651e YS |
425 | if (unlikely(!trace)) |
426 | goto err_fault; | |
427 | ||
ee2a0988 | 428 | if (trace->nr < skip) |
c195651e YS |
429 | goto err_fault; |
430 | ||
ee2a0988 | 431 | trace_nr = trace->nr - skip; |
c195651e YS |
432 | trace_nr = (trace_nr <= num_elem) ? trace_nr : num_elem; |
433 | copy_len = trace_nr * elem_size; | |
ee2a0988 NK |
434 | |
435 | ips = trace->ip + skip; | |
c195651e YS |
436 | if (user && user_build_id) |
437 | stack_map_get_build_id_offset(buf, ips, trace_nr, user); | |
438 | else | |
439 | memcpy(buf, ips, copy_len); | |
440 | ||
441 | if (size > copy_len) | |
442 | memset(buf + copy_len, 0, size - copy_len); | |
443 | return copy_len; | |
444 | ||
445 | err_fault: | |
446 | err = -EFAULT; | |
447 | clear: | |
448 | memset(buf, 0, size); | |
449 | return err; | |
450 | } | |
451 | ||
fa28dcb8 SL |
452 | BPF_CALL_4(bpf_get_stack, struct pt_regs *, regs, void *, buf, u32, size, |
453 | u64, flags) | |
454 | { | |
7b04d6d6 | 455 | return __bpf_get_stack(regs, NULL, NULL, buf, size, flags); |
fa28dcb8 SL |
456 | } |
457 | ||
c195651e YS |
458 | const struct bpf_func_proto bpf_get_stack_proto = { |
459 | .func = bpf_get_stack, | |
460 | .gpl_only = true, | |
461 | .ret_type = RET_INTEGER, | |
462 | .arg1_type = ARG_PTR_TO_CTX, | |
463 | .arg2_type = ARG_PTR_TO_UNINIT_MEM, | |
464 | .arg3_type = ARG_CONST_SIZE_OR_ZERO, | |
465 | .arg4_type = ARG_ANYTHING, | |
466 | }; | |
467 | ||
fa28dcb8 SL |
468 | BPF_CALL_4(bpf_get_task_stack, struct task_struct *, task, void *, buf, |
469 | u32, size, u64, flags) | |
470 | { | |
06ab134c | 471 | struct pt_regs *regs; |
b992f01e | 472 | long res = -EINVAL; |
fa28dcb8 | 473 | |
06ab134c DM |
474 | if (!try_get_task_stack(task)) |
475 | return -EFAULT; | |
476 | ||
477 | regs = task_pt_regs(task); | |
b992f01e NR |
478 | if (regs) |
479 | res = __bpf_get_stack(regs, task, NULL, buf, size, flags); | |
06ab134c DM |
480 | put_task_stack(task); |
481 | ||
482 | return res; | |
fa28dcb8 SL |
483 | } |
484 | ||
fa28dcb8 SL |
485 | const struct bpf_func_proto bpf_get_task_stack_proto = { |
486 | .func = bpf_get_task_stack, | |
487 | .gpl_only = false, | |
488 | .ret_type = RET_INTEGER, | |
489 | .arg1_type = ARG_PTR_TO_BTF_ID, | |
d19ddb47 | 490 | .arg1_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK], |
fa28dcb8 SL |
491 | .arg2_type = ARG_PTR_TO_UNINIT_MEM, |
492 | .arg3_type = ARG_CONST_SIZE_OR_ZERO, | |
493 | .arg4_type = ARG_ANYTHING, | |
fa28dcb8 SL |
494 | }; |
495 | ||
7b04d6d6 SL |
496 | BPF_CALL_4(bpf_get_stack_pe, struct bpf_perf_event_data_kern *, ctx, |
497 | void *, buf, u32, size, u64, flags) | |
498 | { | |
2b9b305f | 499 | struct pt_regs *regs = (struct pt_regs *)(ctx->regs); |
7b04d6d6 SL |
500 | struct perf_event *event = ctx->event; |
501 | struct perf_callchain_entry *trace; | |
502 | bool kernel, user; | |
503 | int err = -EINVAL; | |
504 | __u64 nr_kernel; | |
505 | ||
16817ad7 | 506 | if (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)) |
2b9b305f | 507 | return __bpf_get_stack(regs, NULL, NULL, buf, size, flags); |
7b04d6d6 SL |
508 | |
509 | if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK | | |
510 | BPF_F_USER_BUILD_ID))) | |
511 | goto clear; | |
512 | ||
513 | user = flags & BPF_F_USER_STACK; | |
514 | kernel = !user; | |
515 | ||
516 | err = -EFAULT; | |
517 | trace = ctx->data->callchain; | |
518 | if (unlikely(!trace)) | |
519 | goto clear; | |
520 | ||
521 | nr_kernel = count_kernel_ip(trace); | |
522 | ||
523 | if (kernel) { | |
524 | __u64 nr = trace->nr; | |
525 | ||
526 | trace->nr = nr_kernel; | |
2b9b305f | 527 | err = __bpf_get_stack(regs, NULL, trace, buf, size, flags); |
7b04d6d6 SL |
528 | |
529 | /* restore nr */ | |
530 | trace->nr = nr; | |
531 | } else { /* user */ | |
532 | u64 skip = flags & BPF_F_SKIP_FIELD_MASK; | |
533 | ||
534 | skip += nr_kernel; | |
535 | if (skip > BPF_F_SKIP_FIELD_MASK) | |
536 | goto clear; | |
537 | ||
538 | flags = (flags & ~BPF_F_SKIP_FIELD_MASK) | skip; | |
2b9b305f | 539 | err = __bpf_get_stack(regs, NULL, trace, buf, size, flags); |
7b04d6d6 SL |
540 | } |
541 | return err; | |
542 | ||
543 | clear: | |
544 | memset(buf, 0, size); | |
545 | return err; | |
546 | ||
547 | } | |
548 | ||
549 | const struct bpf_func_proto bpf_get_stack_proto_pe = { | |
550 | .func = bpf_get_stack_pe, | |
551 | .gpl_only = true, | |
552 | .ret_type = RET_INTEGER, | |
553 | .arg1_type = ARG_PTR_TO_CTX, | |
554 | .arg2_type = ARG_PTR_TO_UNINIT_MEM, | |
555 | .arg3_type = ARG_CONST_SIZE_OR_ZERO, | |
556 | .arg4_type = ARG_ANYTHING, | |
557 | }; | |
558 | ||
557c0c6e | 559 | /* Called from eBPF program */ |
d5a3b1f6 | 560 | static void *stack_map_lookup_elem(struct bpf_map *map, void *key) |
557c0c6e | 561 | { |
3b4a63f6 | 562 | return ERR_PTR(-EOPNOTSUPP); |
557c0c6e AS |
563 | } |
564 | ||
565 | /* Called from syscall */ | |
566 | int bpf_stackmap_copy(struct bpf_map *map, void *key, void *value) | |
d5a3b1f6 AS |
567 | { |
568 | struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); | |
557c0c6e AS |
569 | struct stack_map_bucket *bucket, *old_bucket; |
570 | u32 id = *(u32 *)key, trace_len; | |
d5a3b1f6 AS |
571 | |
572 | if (unlikely(id >= smap->n_buckets)) | |
557c0c6e AS |
573 | return -ENOENT; |
574 | ||
575 | bucket = xchg(&smap->buckets[id], NULL); | |
576 | if (!bucket) | |
577 | return -ENOENT; | |
578 | ||
615755a7 SL |
579 | trace_len = bucket->nr * stack_map_data_size(map); |
580 | memcpy(value, bucket->data, trace_len); | |
557c0c6e AS |
581 | memset(value + trace_len, 0, map->value_size - trace_len); |
582 | ||
583 | old_bucket = xchg(&smap->buckets[id], bucket); | |
584 | if (old_bucket) | |
585 | pcpu_freelist_push(&smap->freelist, &old_bucket->fnode); | |
586 | return 0; | |
d5a3b1f6 AS |
587 | } |
588 | ||
16f07c55 YS |
589 | static int stack_map_get_next_key(struct bpf_map *map, void *key, |
590 | void *next_key) | |
d5a3b1f6 | 591 | { |
16f07c55 YS |
592 | struct bpf_stack_map *smap = container_of(map, |
593 | struct bpf_stack_map, map); | |
594 | u32 id; | |
595 | ||
596 | WARN_ON_ONCE(!rcu_read_lock_held()); | |
597 | ||
598 | if (!key) { | |
599 | id = 0; | |
600 | } else { | |
601 | id = *(u32 *)key; | |
602 | if (id >= smap->n_buckets || !smap->buckets[id]) | |
603 | id = 0; | |
604 | else | |
605 | id++; | |
606 | } | |
607 | ||
608 | while (id < smap->n_buckets && !smap->buckets[id]) | |
609 | id++; | |
610 | ||
611 | if (id >= smap->n_buckets) | |
612 | return -ENOENT; | |
613 | ||
614 | *(u32 *)next_key = id; | |
615 | return 0; | |
d5a3b1f6 AS |
616 | } |
617 | ||
d7ba4cc9 JK |
618 | static long stack_map_update_elem(struct bpf_map *map, void *key, void *value, |
619 | u64 map_flags) | |
d5a3b1f6 AS |
620 | { |
621 | return -EINVAL; | |
622 | } | |
623 | ||
624 | /* Called from syscall or from eBPF program */ | |
d7ba4cc9 | 625 | static long stack_map_delete_elem(struct bpf_map *map, void *key) |
d5a3b1f6 AS |
626 | { |
627 | struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); | |
628 | struct stack_map_bucket *old_bucket; | |
629 | u32 id = *(u32 *)key; | |
630 | ||
631 | if (unlikely(id >= smap->n_buckets)) | |
632 | return -E2BIG; | |
633 | ||
634 | old_bucket = xchg(&smap->buckets[id], NULL); | |
635 | if (old_bucket) { | |
557c0c6e | 636 | pcpu_freelist_push(&smap->freelist, &old_bucket->fnode); |
d5a3b1f6 AS |
637 | return 0; |
638 | } else { | |
639 | return -ENOENT; | |
640 | } | |
641 | } | |
642 | ||
643 | /* Called when map->refcnt goes to zero, either from workqueue or from syscall */ | |
644 | static void stack_map_free(struct bpf_map *map) | |
645 | { | |
646 | struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); | |
d5a3b1f6 | 647 | |
d407bd25 | 648 | bpf_map_area_free(smap->elems); |
557c0c6e | 649 | pcpu_freelist_destroy(&smap->freelist); |
d407bd25 | 650 | bpf_map_area_free(smap); |
d5a3b1f6 AS |
651 | put_callchain_buffers(); |
652 | } | |
653 | ||
cbb9b606 YS |
654 | static u64 stack_map_mem_usage(const struct bpf_map *map) |
655 | { | |
656 | struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); | |
657 | u64 value_size = map->value_size; | |
658 | u64 n_buckets = smap->n_buckets; | |
659 | u64 enties = map->max_entries; | |
660 | u64 usage = sizeof(*smap); | |
661 | ||
662 | usage += n_buckets * sizeof(struct stack_map_bucket *); | |
663 | usage += enties * (sizeof(struct stack_map_bucket) + value_size); | |
664 | return usage; | |
665 | } | |
666 | ||
c317ab71 | 667 | BTF_ID_LIST_SINGLE(stack_trace_map_btf_ids, struct, bpf_stack_map) |
14499160 | 668 | const struct bpf_map_ops stack_trace_map_ops = { |
f4d05259 | 669 | .map_meta_equal = bpf_map_meta_equal, |
d5a3b1f6 AS |
670 | .map_alloc = stack_map_alloc, |
671 | .map_free = stack_map_free, | |
672 | .map_get_next_key = stack_map_get_next_key, | |
673 | .map_lookup_elem = stack_map_lookup_elem, | |
674 | .map_update_elem = stack_map_update_elem, | |
675 | .map_delete_elem = stack_map_delete_elem, | |
e8d2bec0 | 676 | .map_check_btf = map_check_no_btf, |
cbb9b606 | 677 | .map_mem_usage = stack_map_mem_usage, |
c317ab71 | 678 | .map_btf_id = &stack_trace_map_btf_ids[0], |
d5a3b1f6 | 679 | }; |