1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2016 Facebook
3 */
4 #include <linux/bpf.h>
5 #include <linux/jhash.h>
6 #include <linux/filter.h>
7 #include <linux/stacktrace.h>
8 #include <linux/perf_event.h>
9 #include <linux/elf.h>
10 #include <linux/pagemap.h>
11 #include <linux/irq_work.h>
12 #include "percpu_freelist.h"
13
14 #define STACK_CREATE_FLAG_MASK \
15 (BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY | \
16 BPF_F_STACK_BUILD_ID)
17
18 struct stack_map_bucket {
19 struct pcpu_freelist_node fnode;
20 u32 hash;
21 u32 nr;
22 u64 data[];
23 };
24
25 struct bpf_stack_map {
26 struct bpf_map map;
27 void *elems;
28 struct pcpu_freelist freelist;
29 u32 n_buckets;
30 struct stack_map_bucket *buckets[];
31 };
32
33 /* irq_work to run up_read() for build_id lookup in nmi context */
34 struct stack_map_irq_work {
35 struct irq_work irq_work;
36 struct rw_semaphore *sem;
37 };
38
do_up_read(struct irq_work * entry)39 static void do_up_read(struct irq_work *entry)
40 {
41 struct stack_map_irq_work *work;
42
43 work = container_of(entry, struct stack_map_irq_work, irq_work);
44 up_read_non_owner(work->sem);
45 work->sem = NULL;
46 }
47
48 static DEFINE_PER_CPU(struct stack_map_irq_work, up_read_work);
49
stack_map_use_build_id(struct bpf_map * map)50 static inline bool stack_map_use_build_id(struct bpf_map *map)
51 {
52 return (map->map_flags & BPF_F_STACK_BUILD_ID);
53 }
54
stack_map_data_size(struct bpf_map * map)55 static inline int stack_map_data_size(struct bpf_map *map)
56 {
57 return stack_map_use_build_id(map) ?
58 sizeof(struct bpf_stack_build_id) : sizeof(u64);
59 }
60
prealloc_elems_and_freelist(struct bpf_stack_map * smap)61 static int prealloc_elems_and_freelist(struct bpf_stack_map *smap)
62 {
63 u64 elem_size = sizeof(struct stack_map_bucket) +
64 (u64)smap->map.value_size;
65 int err;
66
67 smap->elems = bpf_map_area_alloc(elem_size * smap->map.max_entries,
68 smap->map.numa_node);
69 if (!smap->elems)
70 return -ENOMEM;
71
72 err = pcpu_freelist_init(&smap->freelist);
73 if (err)
74 goto free_elems;
75
76 pcpu_freelist_populate(&smap->freelist, smap->elems, elem_size,
77 smap->map.max_entries);
78 return 0;
79
80 free_elems:
81 bpf_map_area_free(smap->elems);
82 return err;
83 }
84
85 /* Called from syscall */
stack_map_alloc(union bpf_attr * attr)86 static struct bpf_map *stack_map_alloc(union bpf_attr *attr)
87 {
88 u32 value_size = attr->value_size;
89 struct bpf_stack_map *smap;
90 struct bpf_map_memory mem;
91 u64 cost, n_buckets;
92 int err;
93
94 if (!capable(CAP_SYS_ADMIN))
95 return ERR_PTR(-EPERM);
96
97 if (attr->map_flags & ~STACK_CREATE_FLAG_MASK)
98 return ERR_PTR(-EINVAL);
99
100 /* check sanity of attributes */
101 if (attr->max_entries == 0 || attr->key_size != 4 ||
102 value_size < 8 || value_size % 8)
103 return ERR_PTR(-EINVAL);
104
105 BUILD_BUG_ON(sizeof(struct bpf_stack_build_id) % sizeof(u64));
106 if (attr->map_flags & BPF_F_STACK_BUILD_ID) {
107 if (value_size % sizeof(struct bpf_stack_build_id) ||
108 value_size / sizeof(struct bpf_stack_build_id)
109 > sysctl_perf_event_max_stack)
110 return ERR_PTR(-EINVAL);
111 } else if (value_size / 8 > sysctl_perf_event_max_stack)
112 return ERR_PTR(-EINVAL);
113
114 /* hash table size must be power of 2; roundup_pow_of_two() can overflow
115 * into UB on 32-bit arches, so check that first
116 */
117 if (attr->max_entries > 1UL << 31)
118 return ERR_PTR(-E2BIG);
119
120 n_buckets = roundup_pow_of_two(attr->max_entries);
121
122 cost = n_buckets * sizeof(struct stack_map_bucket *) + sizeof(*smap);
123 err = bpf_map_charge_init(&mem, cost + attr->max_entries *
124 (sizeof(struct stack_map_bucket) + (u64)value_size));
125 if (err)
126 return ERR_PTR(err);
127
128 smap = bpf_map_area_alloc(cost, bpf_map_attr_numa_node(attr));
129 if (!smap) {
130 bpf_map_charge_finish(&mem);
131 return ERR_PTR(-ENOMEM);
132 }
133
134 bpf_map_init_from_attr(&smap->map, attr);
135 smap->map.value_size = value_size;
136 smap->n_buckets = n_buckets;
137
138 err = get_callchain_buffers(sysctl_perf_event_max_stack);
139 if (err)
140 goto free_charge;
141
142 err = prealloc_elems_and_freelist(smap);
143 if (err)
144 goto put_buffers;
145
146 bpf_map_charge_move(&smap->map.memory, &mem);
147
148 return &smap->map;
149
150 put_buffers:
151 put_callchain_buffers();
152 free_charge:
153 bpf_map_charge_finish(&mem);
154 bpf_map_area_free(smap);
155 return ERR_PTR(err);
156 }
157
158 #define BPF_BUILD_ID 3
159 /*
160 * Parse build id from the note segment. This logic can be shared between
161 * 32-bit and 64-bit system, because Elf32_Nhdr and Elf64_Nhdr are
162 * identical.
163 */
stack_map_parse_build_id(void * page_addr,unsigned char * build_id,void * note_start,Elf32_Word note_size)164 static inline int stack_map_parse_build_id(void *page_addr,
165 unsigned char *build_id,
166 void *note_start,
167 Elf32_Word note_size)
168 {
169 Elf32_Word note_offs = 0, new_offs;
170
171 /* check for overflow */
172 if (note_start < page_addr || note_start + note_size < note_start)
173 return -EINVAL;
174
175 /* only supports note that fits in the first page */
176 if (note_start + note_size > page_addr + PAGE_SIZE)
177 return -EINVAL;
178
179 while (note_offs + sizeof(Elf32_Nhdr) < note_size) {
180 Elf32_Nhdr *nhdr = (Elf32_Nhdr *)(note_start + note_offs);
181
182 if (nhdr->n_type == BPF_BUILD_ID &&
183 nhdr->n_namesz == sizeof("GNU") &&
184 nhdr->n_descsz > 0 &&
185 nhdr->n_descsz <= BPF_BUILD_ID_SIZE) {
186 memcpy(build_id,
187 note_start + note_offs +
188 ALIGN(sizeof("GNU"), 4) + sizeof(Elf32_Nhdr),
189 nhdr->n_descsz);
190 memset(build_id + nhdr->n_descsz, 0,
191 BPF_BUILD_ID_SIZE - nhdr->n_descsz);
192 return 0;
193 }
194 new_offs = note_offs + sizeof(Elf32_Nhdr) +
195 ALIGN(nhdr->n_namesz, 4) + ALIGN(nhdr->n_descsz, 4);
196 if (new_offs <= note_offs) /* overflow */
197 break;
198 note_offs = new_offs;
199 }
200 return -EINVAL;
201 }
202
203 /* Parse build ID from 32-bit ELF */
stack_map_get_build_id_32(void * page_addr,unsigned char * build_id)204 static int stack_map_get_build_id_32(void *page_addr,
205 unsigned char *build_id)
206 {
207 Elf32_Ehdr *ehdr = (Elf32_Ehdr *)page_addr;
208 Elf32_Phdr *phdr;
209 int i;
210
211 /* only supports phdr that fits in one page */
212 if (ehdr->e_phnum >
213 (PAGE_SIZE - sizeof(Elf32_Ehdr)) / sizeof(Elf32_Phdr))
214 return -EINVAL;
215
216 phdr = (Elf32_Phdr *)(page_addr + sizeof(Elf32_Ehdr));
217
218 for (i = 0; i < ehdr->e_phnum; ++i)
219 if (phdr[i].p_type == PT_NOTE)
220 return stack_map_parse_build_id(page_addr, build_id,
221 page_addr + phdr[i].p_offset,
222 phdr[i].p_filesz);
223 return -EINVAL;
224 }
225
226 /* Parse build ID from 64-bit ELF */
stack_map_get_build_id_64(void * page_addr,unsigned char * build_id)227 static int stack_map_get_build_id_64(void *page_addr,
228 unsigned char *build_id)
229 {
230 Elf64_Ehdr *ehdr = (Elf64_Ehdr *)page_addr;
231 Elf64_Phdr *phdr;
232 int i;
233
234 /* only supports phdr that fits in one page */
235 if (ehdr->e_phnum >
236 (PAGE_SIZE - sizeof(Elf64_Ehdr)) / sizeof(Elf64_Phdr))
237 return -EINVAL;
238
239 phdr = (Elf64_Phdr *)(page_addr + sizeof(Elf64_Ehdr));
240
241 for (i = 0; i < ehdr->e_phnum; ++i)
242 if (phdr[i].p_type == PT_NOTE)
243 return stack_map_parse_build_id(page_addr, build_id,
244 page_addr + phdr[i].p_offset,
245 phdr[i].p_filesz);
246 return -EINVAL;
247 }
248
249 /* Parse build ID of ELF file mapped to vma */
stack_map_get_build_id(struct vm_area_struct * vma,unsigned char * build_id)250 static int stack_map_get_build_id(struct vm_area_struct *vma,
251 unsigned char *build_id)
252 {
253 Elf32_Ehdr *ehdr;
254 struct page *page;
255 void *page_addr;
256 int ret;
257
258 /* only works for page backed storage */
259 if (!vma->vm_file)
260 return -EINVAL;
261
262 page = find_get_page(vma->vm_file->f_mapping, 0);
263 if (!page)
264 return -EFAULT; /* page not mapped */
265
266 ret = -EINVAL;
267 page_addr = kmap_atomic(page);
268 ehdr = (Elf32_Ehdr *)page_addr;
269
270 /* compare magic x7f "ELF" */
271 if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0)
272 goto out;
273
274 /* only support executable file and shared object file */
275 if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN)
276 goto out;
277
278 if (ehdr->e_ident[EI_CLASS] == ELFCLASS32)
279 ret = stack_map_get_build_id_32(page_addr, build_id);
280 else if (ehdr->e_ident[EI_CLASS] == ELFCLASS64)
281 ret = stack_map_get_build_id_64(page_addr, build_id);
282 out:
283 kunmap_atomic(page_addr);
284 put_page(page);
285 return ret;
286 }
287
stack_map_get_build_id_offset(struct bpf_stack_build_id * id_offs,u64 * ips,u32 trace_nr,bool user)288 static void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs,
289 u64 *ips, u32 trace_nr, bool user)
290 {
291 int i;
292 struct vm_area_struct *vma;
293 bool irq_work_busy = false;
294 struct stack_map_irq_work *work = NULL;
295
296 if (irqs_disabled()) {
297 work = this_cpu_ptr(&up_read_work);
298 if (work->irq_work.flags & IRQ_WORK_BUSY)
299 /* cannot queue more up_read, fallback */
300 irq_work_busy = true;
301 }
302
303 /*
304 * We cannot do up_read() when the irq is disabled, because of
305 * risk to deadlock with rq_lock. To do build_id lookup when the
306 * irqs are disabled, we need to run up_read() in irq_work. We use
307 * a percpu variable to do the irq_work. If the irq_work is
308 * already used by another lookup, we fall back to report ips.
309 *
310 * Same fallback is used for kernel stack (!user) on a stackmap
311 * with build_id.
312 */
313 if (!user || !current || !current->mm || irq_work_busy ||
314 down_read_trylock(¤t->mm->mmap_sem) == 0) {
315 /* cannot access current->mm, fall back to ips */
316 for (i = 0; i < trace_nr; i++) {
317 id_offs[i].status = BPF_STACK_BUILD_ID_IP;
318 id_offs[i].ip = ips[i];
319 memset(id_offs[i].build_id, 0, BPF_BUILD_ID_SIZE);
320 }
321 return;
322 }
323
324 for (i = 0; i < trace_nr; i++) {
325 vma = find_vma(current->mm, ips[i]);
326 if (!vma || stack_map_get_build_id(vma, id_offs[i].build_id)) {
327 /* per entry fall back to ips */
328 id_offs[i].status = BPF_STACK_BUILD_ID_IP;
329 id_offs[i].ip = ips[i];
330 memset(id_offs[i].build_id, 0, BPF_BUILD_ID_SIZE);
331 continue;
332 }
333 id_offs[i].offset = (vma->vm_pgoff << PAGE_SHIFT) + ips[i]
334 - vma->vm_start;
335 id_offs[i].status = BPF_STACK_BUILD_ID_VALID;
336 }
337
338 if (!work) {
339 up_read(¤t->mm->mmap_sem);
340 } else {
341 work->sem = ¤t->mm->mmap_sem;
342 irq_work_queue(&work->irq_work);
343 /*
344 * The irq_work will release the mmap_sem with
345 * up_read_non_owner(). The rwsem_release() is called
346 * here to release the lock from lockdep's perspective.
347 */
348 rwsem_release(¤t->mm->mmap_sem.dep_map, 1, _RET_IP_);
349 }
350 }
351
BPF_CALL_3(bpf_get_stackid,struct pt_regs *,regs,struct bpf_map *,map,u64,flags)352 BPF_CALL_3(bpf_get_stackid, struct pt_regs *, regs, struct bpf_map *, map,
353 u64, flags)
354 {
355 struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
356 struct perf_callchain_entry *trace;
357 struct stack_map_bucket *bucket, *new_bucket, *old_bucket;
358 u32 max_depth = map->value_size / stack_map_data_size(map);
359 /* stack_map_alloc() checks that max_depth <= sysctl_perf_event_max_stack */
360 u32 init_nr = sysctl_perf_event_max_stack - max_depth;
361 u32 skip = flags & BPF_F_SKIP_FIELD_MASK;
362 u32 hash, id, trace_nr, trace_len;
363 bool user = flags & BPF_F_USER_STACK;
364 bool kernel = !user;
365 u64 *ips;
366 bool hash_matches;
367
368 if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK |
369 BPF_F_FAST_STACK_CMP | BPF_F_REUSE_STACKID)))
370 return -EINVAL;
371
372 trace = get_perf_callchain(regs, init_nr, kernel, user,
373 sysctl_perf_event_max_stack, false, false);
374
375 if (unlikely(!trace))
376 /* couldn't fetch the stack trace */
377 return -EFAULT;
378
379 /* get_perf_callchain() guarantees that trace->nr >= init_nr
380 * and trace-nr <= sysctl_perf_event_max_stack, so trace_nr <= max_depth
381 */
382 trace_nr = trace->nr - init_nr;
383
384 if (trace_nr <= skip)
385 /* skipping more than usable stack trace */
386 return -EFAULT;
387
388 trace_nr -= skip;
389 trace_len = trace_nr * sizeof(u64);
390 ips = trace->ip + skip + init_nr;
391 hash = jhash2((u32 *)ips, trace_len / sizeof(u32), 0);
392 id = hash & (smap->n_buckets - 1);
393 bucket = READ_ONCE(smap->buckets[id]);
394
395 hash_matches = bucket && bucket->hash == hash;
396 /* fast cmp */
397 if (hash_matches && flags & BPF_F_FAST_STACK_CMP)
398 return id;
399
400 if (stack_map_use_build_id(map)) {
401 /* for build_id+offset, pop a bucket before slow cmp */
402 new_bucket = (struct stack_map_bucket *)
403 pcpu_freelist_pop(&smap->freelist);
404 if (unlikely(!new_bucket))
405 return -ENOMEM;
406 new_bucket->nr = trace_nr;
407 stack_map_get_build_id_offset(
408 (struct bpf_stack_build_id *)new_bucket->data,
409 ips, trace_nr, user);
410 trace_len = trace_nr * sizeof(struct bpf_stack_build_id);
411 if (hash_matches && bucket->nr == trace_nr &&
412 memcmp(bucket->data, new_bucket->data, trace_len) == 0) {
413 pcpu_freelist_push(&smap->freelist, &new_bucket->fnode);
414 return id;
415 }
416 if (bucket && !(flags & BPF_F_REUSE_STACKID)) {
417 pcpu_freelist_push(&smap->freelist, &new_bucket->fnode);
418 return -EEXIST;
419 }
420 } else {
421 if (hash_matches && bucket->nr == trace_nr &&
422 memcmp(bucket->data, ips, trace_len) == 0)
423 return id;
424 if (bucket && !(flags & BPF_F_REUSE_STACKID))
425 return -EEXIST;
426
427 new_bucket = (struct stack_map_bucket *)
428 pcpu_freelist_pop(&smap->freelist);
429 if (unlikely(!new_bucket))
430 return -ENOMEM;
431 memcpy(new_bucket->data, ips, trace_len);
432 }
433
434 new_bucket->hash = hash;
435 new_bucket->nr = trace_nr;
436
437 old_bucket = xchg(&smap->buckets[id], new_bucket);
438 if (old_bucket)
439 pcpu_freelist_push(&smap->freelist, &old_bucket->fnode);
440 return id;
441 }
442
443 const struct bpf_func_proto bpf_get_stackid_proto = {
444 .func = bpf_get_stackid,
445 .gpl_only = true,
446 .ret_type = RET_INTEGER,
447 .arg1_type = ARG_PTR_TO_CTX,
448 .arg2_type = ARG_CONST_MAP_PTR,
449 .arg3_type = ARG_ANYTHING,
450 };
451
BPF_CALL_4(bpf_get_stack,struct pt_regs *,regs,void *,buf,u32,size,u64,flags)452 BPF_CALL_4(bpf_get_stack, struct pt_regs *, regs, void *, buf, u32, size,
453 u64, flags)
454 {
455 u32 init_nr, trace_nr, copy_len, elem_size, num_elem;
456 bool user_build_id = flags & BPF_F_USER_BUILD_ID;
457 u32 skip = flags & BPF_F_SKIP_FIELD_MASK;
458 bool user = flags & BPF_F_USER_STACK;
459 struct perf_callchain_entry *trace;
460 bool kernel = !user;
461 int err = -EINVAL;
462 u64 *ips;
463
464 if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK |
465 BPF_F_USER_BUILD_ID)))
466 goto clear;
467 if (kernel && user_build_id)
468 goto clear;
469
470 elem_size = (user && user_build_id) ? sizeof(struct bpf_stack_build_id)
471 : sizeof(u64);
472 if (unlikely(size % elem_size))
473 goto clear;
474
475 num_elem = size / elem_size;
476 if (sysctl_perf_event_max_stack < num_elem)
477 init_nr = 0;
478 else
479 init_nr = sysctl_perf_event_max_stack - num_elem;
480 trace = get_perf_callchain(regs, init_nr, kernel, user,
481 sysctl_perf_event_max_stack, false, false);
482 if (unlikely(!trace))
483 goto err_fault;
484
485 trace_nr = trace->nr - init_nr;
486 if (trace_nr < skip)
487 goto err_fault;
488
489 trace_nr -= skip;
490 trace_nr = (trace_nr <= num_elem) ? trace_nr : num_elem;
491 copy_len = trace_nr * elem_size;
492 ips = trace->ip + skip + init_nr;
493 if (user && user_build_id)
494 stack_map_get_build_id_offset(buf, ips, trace_nr, user);
495 else
496 memcpy(buf, ips, copy_len);
497
498 if (size > copy_len)
499 memset(buf + copy_len, 0, size - copy_len);
500 return copy_len;
501
502 err_fault:
503 err = -EFAULT;
504 clear:
505 memset(buf, 0, size);
506 return err;
507 }
508
509 const struct bpf_func_proto bpf_get_stack_proto = {
510 .func = bpf_get_stack,
511 .gpl_only = true,
512 .ret_type = RET_INTEGER,
513 .arg1_type = ARG_PTR_TO_CTX,
514 .arg2_type = ARG_PTR_TO_UNINIT_MEM,
515 .arg3_type = ARG_CONST_SIZE_OR_ZERO,
516 .arg4_type = ARG_ANYTHING,
517 };
518
519 /* Called from eBPF program */
stack_map_lookup_elem(struct bpf_map * map,void * key)520 static void *stack_map_lookup_elem(struct bpf_map *map, void *key)
521 {
522 return ERR_PTR(-EOPNOTSUPP);
523 }
524
525 /* Called from syscall */
bpf_stackmap_copy(struct bpf_map * map,void * key,void * value)526 int bpf_stackmap_copy(struct bpf_map *map, void *key, void *value)
527 {
528 struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
529 struct stack_map_bucket *bucket, *old_bucket;
530 u32 id = *(u32 *)key, trace_len;
531
532 if (unlikely(id >= smap->n_buckets))
533 return -ENOENT;
534
535 bucket = xchg(&smap->buckets[id], NULL);
536 if (!bucket)
537 return -ENOENT;
538
539 trace_len = bucket->nr * stack_map_data_size(map);
540 memcpy(value, bucket->data, trace_len);
541 memset(value + trace_len, 0, map->value_size - trace_len);
542
543 old_bucket = xchg(&smap->buckets[id], bucket);
544 if (old_bucket)
545 pcpu_freelist_push(&smap->freelist, &old_bucket->fnode);
546 return 0;
547 }
548
stack_map_get_next_key(struct bpf_map * map,void * key,void * next_key)549 static int stack_map_get_next_key(struct bpf_map *map, void *key,
550 void *next_key)
551 {
552 struct bpf_stack_map *smap = container_of(map,
553 struct bpf_stack_map, map);
554 u32 id;
555
556 WARN_ON_ONCE(!rcu_read_lock_held());
557
558 if (!key) {
559 id = 0;
560 } else {
561 id = *(u32 *)key;
562 if (id >= smap->n_buckets || !smap->buckets[id])
563 id = 0;
564 else
565 id++;
566 }
567
568 while (id < smap->n_buckets && !smap->buckets[id])
569 id++;
570
571 if (id >= smap->n_buckets)
572 return -ENOENT;
573
574 *(u32 *)next_key = id;
575 return 0;
576 }
577
stack_map_update_elem(struct bpf_map * map,void * key,void * value,u64 map_flags)578 static int stack_map_update_elem(struct bpf_map *map, void *key, void *value,
579 u64 map_flags)
580 {
581 return -EINVAL;
582 }
583
584 /* Called from syscall or from eBPF program */
stack_map_delete_elem(struct bpf_map * map,void * key)585 static int stack_map_delete_elem(struct bpf_map *map, void *key)
586 {
587 struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
588 struct stack_map_bucket *old_bucket;
589 u32 id = *(u32 *)key;
590
591 if (unlikely(id >= smap->n_buckets))
592 return -E2BIG;
593
594 old_bucket = xchg(&smap->buckets[id], NULL);
595 if (old_bucket) {
596 pcpu_freelist_push(&smap->freelist, &old_bucket->fnode);
597 return 0;
598 } else {
599 return -ENOENT;
600 }
601 }
602
603 /* Called when map->refcnt goes to zero, either from workqueue or from syscall */
stack_map_free(struct bpf_map * map)604 static void stack_map_free(struct bpf_map *map)
605 {
606 struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
607
608 /* wait for bpf programs to complete before freeing stack map */
609 synchronize_rcu();
610
611 bpf_map_area_free(smap->elems);
612 pcpu_freelist_destroy(&smap->freelist);
613 bpf_map_area_free(smap);
614 put_callchain_buffers();
615 }
616
617 const struct bpf_map_ops stack_trace_map_ops = {
618 .map_alloc = stack_map_alloc,
619 .map_free = stack_map_free,
620 .map_get_next_key = stack_map_get_next_key,
621 .map_lookup_elem = stack_map_lookup_elem,
622 .map_update_elem = stack_map_update_elem,
623 .map_delete_elem = stack_map_delete_elem,
624 .map_check_btf = map_check_no_btf,
625 };
626
stack_map_init(void)627 static int __init stack_map_init(void)
628 {
629 int cpu;
630 struct stack_map_irq_work *work;
631
632 for_each_possible_cpu(cpu) {
633 work = per_cpu_ptr(&up_read_work, cpu);
634 init_irq_work(&work->irq_work, do_up_read);
635 }
636 return 0;
637 }
638 subsys_initcall(stack_map_init);
639