1// SPDX-License-Identifier: GPL-2.0-only
2/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
3 * Copyright (c) 2016,2017 Facebook
4 */
5#include <linux/bpf.h>
6#include <linux/btf.h>
7#include <linux/err.h>
8#include <linux/slab.h>
9#include <linux/mm.h>
10#include <linux/filter.h>
11#include <linux/perf_event.h>
12#include <uapi/linux/btf.h>
13#include <linux/rcupdate_trace.h>
14#include <linux/btf_ids.h>
15#include <crypto/sha2.h>
16
17#include "map_in_map.h"
18
19#define ARRAY_CREATE_FLAG_MASK \
20 (BPF_F_NUMA_NODE | BPF_F_MMAPABLE | BPF_F_ACCESS_MASK | \
21 BPF_F_PRESERVE_ELEMS | BPF_F_INNER_MAP)
22
23static void bpf_array_free_percpu(struct bpf_array *array)
24{
25 int i;
26
27 for (i = 0; i < array->map.max_entries; i++) {
28 free_percpu(pdata: array->pptrs[i]);
29 cond_resched();
30 }
31}
32
33static int bpf_array_alloc_percpu(struct bpf_array *array)
34{
35 void __percpu *ptr;
36 int i;
37
38 for (i = 0; i < array->map.max_entries; i++) {
39 ptr = bpf_map_alloc_percpu(map: &array->map, size: array->elem_size, align: 8,
40 GFP_USER | __GFP_NOWARN);
41 if (!ptr) {
42 bpf_array_free_percpu(array);
43 return -ENOMEM;
44 }
45 array->pptrs[i] = ptr;
46 cond_resched();
47 }
48
49 return 0;
50}
51
52/* Called from syscall */
53int array_map_alloc_check(union bpf_attr *attr)
54{
55 bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
56 int numa_node = bpf_map_attr_numa_node(attr);
57
58 /* check sanity of attributes */
59 if (attr->max_entries == 0 || attr->key_size != 4 ||
60 attr->value_size == 0 ||
61 attr->map_flags & ~ARRAY_CREATE_FLAG_MASK ||
62 !bpf_map_flags_access_ok(access_flags: attr->map_flags) ||
63 (percpu && numa_node != NUMA_NO_NODE))
64 return -EINVAL;
65
66 if (attr->map_type != BPF_MAP_TYPE_ARRAY &&
67 attr->map_flags & (BPF_F_MMAPABLE | BPF_F_INNER_MAP))
68 return -EINVAL;
69
70 if (attr->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY &&
71 attr->map_flags & BPF_F_PRESERVE_ELEMS)
72 return -EINVAL;
73
74 /* avoid overflow on round_up(map->value_size) */
75 if (attr->value_size > INT_MAX)
76 return -E2BIG;
77 /* percpu map value size is bound by PCPU_MIN_UNIT_SIZE */
78 if (percpu && round_up(attr->value_size, 8) > PCPU_MIN_UNIT_SIZE)
79 return -E2BIG;
80
81 return 0;
82}
83
84static struct bpf_map *array_map_alloc(union bpf_attr *attr)
85{
86 bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
87 int numa_node = bpf_map_attr_numa_node(attr);
88 u32 elem_size, index_mask, max_entries;
89 bool bypass_spec_v1 = bpf_bypass_spec_v1(NULL);
90 u64 array_size, mask64;
91 struct bpf_array *array;
92
93 elem_size = round_up(attr->value_size, 8);
94
95 max_entries = attr->max_entries;
96
97 /* On 32 bit archs roundup_pow_of_two() with max_entries that has
98 * upper most bit set in u32 space is undefined behavior due to
99 * resulting 1U << 32, so do it manually here in u64 space.
100 */
101 mask64 = fls_long(l: max_entries - 1);
102 mask64 = 1ULL << mask64;
103 mask64 -= 1;
104
105 index_mask = mask64;
106 if (!bypass_spec_v1) {
107 /* round up array size to nearest power of 2,
108 * since cpu will speculate within index_mask limits
109 */
110 max_entries = index_mask + 1;
111 /* Check for overflows. */
112 if (max_entries < attr->max_entries)
113 return ERR_PTR(error: -E2BIG);
114 }
115
116 array_size = sizeof(*array);
117 if (percpu) {
118 array_size += (u64) max_entries * sizeof(void *);
119 } else {
120 /* rely on vmalloc() to return page-aligned memory and
121 * ensure array->value is exactly page-aligned
122 */
123 if (attr->map_flags & BPF_F_MMAPABLE) {
124 array_size = PAGE_ALIGN(array_size);
125 array_size += PAGE_ALIGN((u64) max_entries * elem_size);
126 } else {
127 array_size += (u64) max_entries * elem_size;
128 }
129 }
130
131 /* allocate all map elements and zero-initialize them */
132 if (attr->map_flags & BPF_F_MMAPABLE) {
133 void *data;
134
135 /* kmalloc'ed memory can't be mmap'ed, use explicit vmalloc */
136 data = bpf_map_area_mmapable_alloc(size: array_size, numa_node);
137 if (!data)
138 return ERR_PTR(error: -ENOMEM);
139 array = data + PAGE_ALIGN(sizeof(struct bpf_array))
140 - offsetof(struct bpf_array, value);
141 } else {
142 array = bpf_map_area_alloc(size: array_size, numa_node);
143 }
144 if (!array)
145 return ERR_PTR(error: -ENOMEM);
146 array->index_mask = index_mask;
147 array->map.bypass_spec_v1 = bypass_spec_v1;
148
149 /* copy mandatory map attributes */
150 bpf_map_init_from_attr(map: &array->map, attr);
151 array->elem_size = elem_size;
152
153 if (percpu && bpf_array_alloc_percpu(array)) {
154 bpf_map_area_free(base: array);
155 return ERR_PTR(error: -ENOMEM);
156 }
157
158 return &array->map;
159}
160
161static void *array_map_elem_ptr(struct bpf_array* array, u32 index)
162{
163 return array->value + (u64)array->elem_size * index;
164}
165
166/* Called from syscall or from eBPF program */
167static void *array_map_lookup_elem(struct bpf_map *map, void *key)
168{
169 struct bpf_array *array = container_of(map, struct bpf_array, map);
170 u32 index = *(u32 *)key;
171
172 if (unlikely(index >= array->map.max_entries))
173 return NULL;
174
175 return array->value + (u64)array->elem_size * (index & array->index_mask);
176}
177
178static int array_map_get_hash(struct bpf_map *map, u32 hash_buf_size,
179 void *hash_buf)
180{
181 struct bpf_array *array = container_of(map, struct bpf_array, map);
182
183 sha256(data: array->value, len: (u64)array->elem_size * array->map.max_entries,
184 out: hash_buf);
185 memcpy(array->map.sha, hash_buf, sizeof(array->map.sha));
186 return 0;
187}
188
189static int array_map_direct_value_addr(const struct bpf_map *map, u64 *imm,
190 u32 off)
191{
192 struct bpf_array *array = container_of(map, struct bpf_array, map);
193
194 if (map->max_entries != 1)
195 return -ENOTSUPP;
196 if (off >= map->value_size)
197 return -EINVAL;
198
199 *imm = (unsigned long)array->value;
200 return 0;
201}
202
203static int array_map_direct_value_meta(const struct bpf_map *map, u64 imm,
204 u32 *off)
205{
206 struct bpf_array *array = container_of(map, struct bpf_array, map);
207 u64 base = (unsigned long)array->value;
208 u64 range = array->elem_size;
209
210 if (map->max_entries != 1)
211 return -ENOTSUPP;
212 if (imm < base || imm >= base + range)
213 return -ENOENT;
214
215 *off = imm - base;
216 return 0;
217}
218
219/* emit BPF instructions equivalent to C code of array_map_lookup_elem() */
220static int array_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
221{
222 struct bpf_array *array = container_of(map, struct bpf_array, map);
223 struct bpf_insn *insn = insn_buf;
224 u32 elem_size = array->elem_size;
225 const int ret = BPF_REG_0;
226 const int map_ptr = BPF_REG_1;
227 const int index = BPF_REG_2;
228
229 if (map->map_flags & BPF_F_INNER_MAP)
230 return -EOPNOTSUPP;
231
232 *insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
233 *insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
234 if (!map->bypass_spec_v1) {
235 *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 4);
236 *insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
237 } else {
238 *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 3);
239 }
240
241 if (is_power_of_2(n: elem_size)) {
242 *insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(elem_size));
243 } else {
244 *insn++ = BPF_ALU64_IMM(BPF_MUL, ret, elem_size);
245 }
246 *insn++ = BPF_ALU64_REG(BPF_ADD, ret, map_ptr);
247 *insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
248 *insn++ = BPF_MOV64_IMM(ret, 0);
249 return insn - insn_buf;
250}
251
252/* Called from eBPF program */
253static void *percpu_array_map_lookup_elem(struct bpf_map *map, void *key)
254{
255 struct bpf_array *array = container_of(map, struct bpf_array, map);
256 u32 index = *(u32 *)key;
257
258 if (unlikely(index >= array->map.max_entries))
259 return NULL;
260
261 return this_cpu_ptr(array->pptrs[index & array->index_mask]);
262}
263
264/* emit BPF instructions equivalent to C code of percpu_array_map_lookup_elem() */
265static int percpu_array_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
266{
267 struct bpf_array *array = container_of(map, struct bpf_array, map);
268 struct bpf_insn *insn = insn_buf;
269
270 if (!bpf_jit_supports_percpu_insn())
271 return -EOPNOTSUPP;
272
273 if (map->map_flags & BPF_F_INNER_MAP)
274 return -EOPNOTSUPP;
275
276 BUILD_BUG_ON(offsetof(struct bpf_array, map) != 0);
277 *insn++ = BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, offsetof(struct bpf_array, pptrs));
278
279 *insn++ = BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_2, 0);
280 if (!map->bypass_spec_v1) {
281 *insn++ = BPF_JMP_IMM(BPF_JGE, BPF_REG_0, map->max_entries, 6);
282 *insn++ = BPF_ALU32_IMM(BPF_AND, BPF_REG_0, array->index_mask);
283 } else {
284 *insn++ = BPF_JMP_IMM(BPF_JGE, BPF_REG_0, map->max_entries, 5);
285 }
286
287 *insn++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_0, 3);
288 *insn++ = BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1);
289 *insn++ = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0);
290 *insn++ = BPF_MOV64_PERCPU_REG(BPF_REG_0, BPF_REG_0);
291 *insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
292 *insn++ = BPF_MOV64_IMM(BPF_REG_0, 0);
293 return insn - insn_buf;
294}
295
296static void *percpu_array_map_lookup_percpu_elem(struct bpf_map *map, void *key, u32 cpu)
297{
298 struct bpf_array *array = container_of(map, struct bpf_array, map);
299 u32 index = *(u32 *)key;
300
301 if (cpu >= nr_cpu_ids)
302 return NULL;
303
304 if (unlikely(index >= array->map.max_entries))
305 return NULL;
306
307 return per_cpu_ptr(array->pptrs[index & array->index_mask], cpu);
308}
309
310int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value)
311{
312 struct bpf_array *array = container_of(map, struct bpf_array, map);
313 u32 index = *(u32 *)key;
314 void __percpu *pptr;
315 int cpu, off = 0;
316 u32 size;
317
318 if (unlikely(index >= array->map.max_entries))
319 return -ENOENT;
320
321 /* per_cpu areas are zero-filled and bpf programs can only
322 * access 'value_size' of them, so copying rounded areas
323 * will not leak any kernel data
324 */
325 size = array->elem_size;
326 rcu_read_lock();
327 pptr = array->pptrs[index & array->index_mask];
328 for_each_possible_cpu(cpu) {
329 copy_map_value_long(map, dst: value + off, per_cpu_ptr(pptr, cpu));
330 check_and_init_map_value(map, dst: value + off);
331 off += size;
332 }
333 rcu_read_unlock();
334 return 0;
335}
336
337/* Called from syscall */
338int bpf_array_get_next_key(struct bpf_map *map, void *key, void *next_key)
339{
340 u32 index = key ? *(u32 *)key : U32_MAX;
341 u32 *next = (u32 *)next_key;
342
343 if (index >= map->max_entries) {
344 *next = 0;
345 return 0;
346 }
347
348 if (index == map->max_entries - 1)
349 return -ENOENT;
350
351 *next = index + 1;
352 return 0;
353}
354
355/* Called from syscall or from eBPF program */
356static long array_map_update_elem(struct bpf_map *map, void *key, void *value,
357 u64 map_flags)
358{
359 struct bpf_array *array = container_of(map, struct bpf_array, map);
360 u32 index = *(u32 *)key;
361 char *val;
362
363 if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST))
364 /* unknown flags */
365 return -EINVAL;
366
367 if (unlikely(index >= array->map.max_entries))
368 /* all elements were pre-allocated, cannot insert a new one */
369 return -E2BIG;
370
371 if (unlikely(map_flags & BPF_NOEXIST))
372 /* all elements already exist */
373 return -EEXIST;
374
375 if (unlikely((map_flags & BPF_F_LOCK) &&
376 !btf_record_has_field(map->record, BPF_SPIN_LOCK)))
377 return -EINVAL;
378
379 if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
380 val = this_cpu_ptr(array->pptrs[index & array->index_mask]);
381 copy_map_value(map, dst: val, src: value);
382 bpf_obj_free_fields(rec: array->map.record, obj: val);
383 } else {
384 val = array->value +
385 (u64)array->elem_size * (index & array->index_mask);
386 if (map_flags & BPF_F_LOCK)
387 copy_map_value_locked(map, dst: val, src: value, lock_src: false);
388 else
389 copy_map_value(map, dst: val, src: value);
390 bpf_obj_free_fields(rec: array->map.record, obj: val);
391 }
392 return 0;
393}
394
395int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
396 u64 map_flags)
397{
398 struct bpf_array *array = container_of(map, struct bpf_array, map);
399 u32 index = *(u32 *)key;
400 void __percpu *pptr;
401 int cpu, off = 0;
402 u32 size;
403
404 if (unlikely(map_flags > BPF_EXIST))
405 /* unknown flags */
406 return -EINVAL;
407
408 if (unlikely(index >= array->map.max_entries))
409 /* all elements were pre-allocated, cannot insert a new one */
410 return -E2BIG;
411
412 if (unlikely(map_flags == BPF_NOEXIST))
413 /* all elements already exist */
414 return -EEXIST;
415
416 /* the user space will provide round_up(value_size, 8) bytes that
417 * will be copied into per-cpu area. bpf programs can only access
418 * value_size of it. During lookup the same extra bytes will be
419 * returned or zeros which were zero-filled by percpu_alloc,
420 * so no kernel data leaks possible
421 */
422 size = array->elem_size;
423 rcu_read_lock();
424 pptr = array->pptrs[index & array->index_mask];
425 for_each_possible_cpu(cpu) {
426 copy_map_value_long(map, per_cpu_ptr(pptr, cpu), src: value + off);
427 bpf_obj_free_fields(rec: array->map.record, per_cpu_ptr(pptr, cpu));
428 off += size;
429 }
430 rcu_read_unlock();
431 return 0;
432}
433
434/* Called from syscall or from eBPF program */
435static long array_map_delete_elem(struct bpf_map *map, void *key)
436{
437 return -EINVAL;
438}
439
440static void *array_map_vmalloc_addr(struct bpf_array *array)
441{
442 return (void *)round_down((unsigned long)array, PAGE_SIZE);
443}
444
445static void array_map_free_internal_structs(struct bpf_map *map)
446{
447 struct bpf_array *array = container_of(map, struct bpf_array, map);
448 int i;
449
450 /* We only free internal structs on uref dropping to zero */
451 if (!bpf_map_has_internal_structs(map))
452 return;
453
454 for (i = 0; i < array->map.max_entries; i++)
455 bpf_map_free_internal_structs(map, obj: array_map_elem_ptr(array, index: i));
456}
457
458/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
459static void array_map_free(struct bpf_map *map)
460{
461 struct bpf_array *array = container_of(map, struct bpf_array, map);
462 int i;
463
464 if (!IS_ERR_OR_NULL(ptr: map->record)) {
465 if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
466 for (i = 0; i < array->map.max_entries; i++) {
467 void __percpu *pptr = array->pptrs[i & array->index_mask];
468 int cpu;
469
470 for_each_possible_cpu(cpu) {
471 bpf_obj_free_fields(rec: map->record, per_cpu_ptr(pptr, cpu));
472 cond_resched();
473 }
474 }
475 } else {
476 for (i = 0; i < array->map.max_entries; i++)
477 bpf_obj_free_fields(rec: map->record, obj: array_map_elem_ptr(array, index: i));
478 }
479 }
480
481 if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
482 bpf_array_free_percpu(array);
483
484 if (array->map.map_flags & BPF_F_MMAPABLE)
485 bpf_map_area_free(base: array_map_vmalloc_addr(array));
486 else
487 bpf_map_area_free(base: array);
488}
489
490static void array_map_seq_show_elem(struct bpf_map *map, void *key,
491 struct seq_file *m)
492{
493 void *value;
494
495 rcu_read_lock();
496
497 value = array_map_lookup_elem(map, key);
498 if (!value) {
499 rcu_read_unlock();
500 return;
501 }
502
503 if (map->btf_key_type_id)
504 seq_printf(m, fmt: "%u: ", *(u32 *)key);
505 btf_type_seq_show(btf: map->btf, type_id: map->btf_value_type_id, obj: value, m);
506 seq_putc(m, c: '\n');
507
508 rcu_read_unlock();
509}
510
511static void percpu_array_map_seq_show_elem(struct bpf_map *map, void *key,
512 struct seq_file *m)
513{
514 struct bpf_array *array = container_of(map, struct bpf_array, map);
515 u32 index = *(u32 *)key;
516 void __percpu *pptr;
517 int cpu;
518
519 rcu_read_lock();
520
521 seq_printf(m, fmt: "%u: {\n", *(u32 *)key);
522 pptr = array->pptrs[index & array->index_mask];
523 for_each_possible_cpu(cpu) {
524 seq_printf(m, fmt: "\tcpu%d: ", cpu);
525 btf_type_seq_show(btf: map->btf, type_id: map->btf_value_type_id,
526 per_cpu_ptr(pptr, cpu), m);
527 seq_putc(m, c: '\n');
528 }
529 seq_puts(m, s: "}\n");
530
531 rcu_read_unlock();
532}
533
534static int array_map_check_btf(const struct bpf_map *map,
535 const struct btf *btf,
536 const struct btf_type *key_type,
537 const struct btf_type *value_type)
538{
539 /* One exception for keyless BTF: .bss/.data/.rodata map */
540 if (btf_type_is_void(t: key_type)) {
541 if (map->map_type != BPF_MAP_TYPE_ARRAY ||
542 map->max_entries != 1)
543 return -EINVAL;
544
545 if (BTF_INFO_KIND(value_type->info) != BTF_KIND_DATASEC)
546 return -EINVAL;
547
548 return 0;
549 }
550
551 /*
552 * Bpf array can only take a u32 key. This check makes sure
553 * that the btf matches the attr used during map_create.
554 */
555 if (!btf_type_is_i32(t: key_type))
556 return -EINVAL;
557
558 return 0;
559}
560
561static int array_map_mmap(struct bpf_map *map, struct vm_area_struct *vma)
562{
563 struct bpf_array *array = container_of(map, struct bpf_array, map);
564 pgoff_t pgoff = PAGE_ALIGN(sizeof(*array)) >> PAGE_SHIFT;
565
566 if (!(map->map_flags & BPF_F_MMAPABLE))
567 return -EINVAL;
568
569 if (vma->vm_pgoff * PAGE_SIZE + (vma->vm_end - vma->vm_start) >
570 PAGE_ALIGN((u64)array->map.max_entries * array->elem_size))
571 return -EINVAL;
572
573 return remap_vmalloc_range(vma, addr: array_map_vmalloc_addr(array),
574 pgoff: vma->vm_pgoff + pgoff);
575}
576
577static bool array_map_meta_equal(const struct bpf_map *meta0,
578 const struct bpf_map *meta1)
579{
580 if (!bpf_map_meta_equal(meta0, meta1))
581 return false;
582 return meta0->map_flags & BPF_F_INNER_MAP ? true :
583 meta0->max_entries == meta1->max_entries;
584}
585
586struct bpf_iter_seq_array_map_info {
587 struct bpf_map *map;
588 void *percpu_value_buf;
589 u32 index;
590};
591
592static void *bpf_array_map_seq_start(struct seq_file *seq, loff_t *pos)
593{
594 struct bpf_iter_seq_array_map_info *info = seq->private;
595 struct bpf_map *map = info->map;
596 struct bpf_array *array;
597 u32 index;
598
599 if (info->index >= map->max_entries)
600 return NULL;
601
602 if (*pos == 0)
603 ++*pos;
604 array = container_of(map, struct bpf_array, map);
605 index = info->index & array->index_mask;
606 if (info->percpu_value_buf)
607 return (void *)(uintptr_t)array->pptrs[index];
608 return array_map_elem_ptr(array, index);
609}
610
611static void *bpf_array_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
612{
613 struct bpf_iter_seq_array_map_info *info = seq->private;
614 struct bpf_map *map = info->map;
615 struct bpf_array *array;
616 u32 index;
617
618 ++*pos;
619 ++info->index;
620 if (info->index >= map->max_entries)
621 return NULL;
622
623 array = container_of(map, struct bpf_array, map);
624 index = info->index & array->index_mask;
625 if (info->percpu_value_buf)
626 return (void *)(uintptr_t)array->pptrs[index];
627 return array_map_elem_ptr(array, index);
628}
629
630static int __bpf_array_map_seq_show(struct seq_file *seq, void *v)
631{
632 struct bpf_iter_seq_array_map_info *info = seq->private;
633 struct bpf_iter__bpf_map_elem ctx = {};
634 struct bpf_map *map = info->map;
635 struct bpf_array *array = container_of(map, struct bpf_array, map);
636 struct bpf_iter_meta meta;
637 struct bpf_prog *prog;
638 int off = 0, cpu = 0;
639 void __percpu *pptr;
640 u32 size;
641
642 meta.seq = seq;
643 prog = bpf_iter_get_info(meta: &meta, in_stop: v == NULL);
644 if (!prog)
645 return 0;
646
647 ctx.meta = &meta;
648 ctx.map = info->map;
649 if (v) {
650 ctx.key = &info->index;
651
652 if (!info->percpu_value_buf) {
653 ctx.value = v;
654 } else {
655 pptr = (void __percpu *)(uintptr_t)v;
656 size = array->elem_size;
657 for_each_possible_cpu(cpu) {
658 copy_map_value_long(map, dst: info->percpu_value_buf + off,
659 per_cpu_ptr(pptr, cpu));
660 check_and_init_map_value(map, dst: info->percpu_value_buf + off);
661 off += size;
662 }
663 ctx.value = info->percpu_value_buf;
664 }
665 }
666
667 return bpf_iter_run_prog(prog, ctx: &ctx);
668}
669
670static int bpf_array_map_seq_show(struct seq_file *seq, void *v)
671{
672 return __bpf_array_map_seq_show(seq, v);
673}
674
675static void bpf_array_map_seq_stop(struct seq_file *seq, void *v)
676{
677 if (!v)
678 (void)__bpf_array_map_seq_show(seq, NULL);
679}
680
681static int bpf_iter_init_array_map(void *priv_data,
682 struct bpf_iter_aux_info *aux)
683{
684 struct bpf_iter_seq_array_map_info *seq_info = priv_data;
685 struct bpf_map *map = aux->map;
686 struct bpf_array *array = container_of(map, struct bpf_array, map);
687 void *value_buf;
688 u32 buf_size;
689
690 if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
691 buf_size = array->elem_size * num_possible_cpus();
692 value_buf = kmalloc(buf_size, GFP_USER | __GFP_NOWARN);
693 if (!value_buf)
694 return -ENOMEM;
695
696 seq_info->percpu_value_buf = value_buf;
697 }
698
699 /* bpf_iter_attach_map() acquires a map uref, and the uref may be
700 * released before or in the middle of iterating map elements, so
701 * acquire an extra map uref for iterator.
702 */
703 bpf_map_inc_with_uref(map);
704 seq_info->map = map;
705 return 0;
706}
707
708static void bpf_iter_fini_array_map(void *priv_data)
709{
710 struct bpf_iter_seq_array_map_info *seq_info = priv_data;
711
712 bpf_map_put_with_uref(map: seq_info->map);
713 kfree(objp: seq_info->percpu_value_buf);
714}
715
716static const struct seq_operations bpf_array_map_seq_ops = {
717 .start = bpf_array_map_seq_start,
718 .next = bpf_array_map_seq_next,
719 .stop = bpf_array_map_seq_stop,
720 .show = bpf_array_map_seq_show,
721};
722
723static const struct bpf_iter_seq_info iter_seq_info = {
724 .seq_ops = &bpf_array_map_seq_ops,
725 .init_seq_private = bpf_iter_init_array_map,
726 .fini_seq_private = bpf_iter_fini_array_map,
727 .seq_priv_size = sizeof(struct bpf_iter_seq_array_map_info),
728};
729
730static long bpf_for_each_array_elem(struct bpf_map *map, bpf_callback_t callback_fn,
731 void *callback_ctx, u64 flags)
732{
733 u32 i, key, num_elems = 0;
734 struct bpf_array *array;
735 bool is_percpu;
736 u64 ret = 0;
737 void *val;
738
739 cant_migrate();
740
741 if (flags != 0)
742 return -EINVAL;
743
744 is_percpu = map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
745 array = container_of(map, struct bpf_array, map);
746 for (i = 0; i < map->max_entries; i++) {
747 if (is_percpu)
748 val = this_cpu_ptr(array->pptrs[i]);
749 else
750 val = array_map_elem_ptr(array, index: i);
751 num_elems++;
752 key = i;
753 ret = callback_fn((u64)(long)map, (u64)(long)&key,
754 (u64)(long)val, (u64)(long)callback_ctx, 0);
755 /* return value: 0 - continue, 1 - stop and return */
756 if (ret)
757 break;
758 }
759
760 return num_elems;
761}
762
763static u64 array_map_mem_usage(const struct bpf_map *map)
764{
765 struct bpf_array *array = container_of(map, struct bpf_array, map);
766 bool percpu = map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
767 u32 elem_size = array->elem_size;
768 u64 entries = map->max_entries;
769 u64 usage = sizeof(*array);
770
771 if (percpu) {
772 usage += entries * sizeof(void *);
773 usage += entries * elem_size * num_possible_cpus();
774 } else {
775 if (map->map_flags & BPF_F_MMAPABLE) {
776 usage = PAGE_ALIGN(usage);
777 usage += PAGE_ALIGN(entries * elem_size);
778 } else {
779 usage += entries * elem_size;
780 }
781 }
782 return usage;
783}
784
785BTF_ID_LIST_SINGLE(array_map_btf_ids, struct, bpf_array)
786const struct bpf_map_ops array_map_ops = {
787 .map_meta_equal = array_map_meta_equal,
788 .map_alloc_check = array_map_alloc_check,
789 .map_alloc = array_map_alloc,
790 .map_free = array_map_free,
791 .map_get_next_key = bpf_array_get_next_key,
792 .map_release_uref = array_map_free_internal_structs,
793 .map_lookup_elem = array_map_lookup_elem,
794 .map_update_elem = array_map_update_elem,
795 .map_delete_elem = array_map_delete_elem,
796 .map_gen_lookup = array_map_gen_lookup,
797 .map_direct_value_addr = array_map_direct_value_addr,
798 .map_direct_value_meta = array_map_direct_value_meta,
799 .map_mmap = array_map_mmap,
800 .map_seq_show_elem = array_map_seq_show_elem,
801 .map_check_btf = array_map_check_btf,
802 .map_lookup_batch = generic_map_lookup_batch,
803 .map_update_batch = generic_map_update_batch,
804 .map_set_for_each_callback_args = map_set_for_each_callback_args,
805 .map_for_each_callback = bpf_for_each_array_elem,
806 .map_mem_usage = array_map_mem_usage,
807 .map_btf_id = &array_map_btf_ids[0],
808 .iter_seq_info = &iter_seq_info,
809 .map_get_hash = &array_map_get_hash,
810};
811
812const struct bpf_map_ops percpu_array_map_ops = {
813 .map_meta_equal = bpf_map_meta_equal,
814 .map_alloc_check = array_map_alloc_check,
815 .map_alloc = array_map_alloc,
816 .map_free = array_map_free,
817 .map_get_next_key = bpf_array_get_next_key,
818 .map_lookup_elem = percpu_array_map_lookup_elem,
819 .map_gen_lookup = percpu_array_map_gen_lookup,
820 .map_update_elem = array_map_update_elem,
821 .map_delete_elem = array_map_delete_elem,
822 .map_lookup_percpu_elem = percpu_array_map_lookup_percpu_elem,
823 .map_seq_show_elem = percpu_array_map_seq_show_elem,
824 .map_check_btf = array_map_check_btf,
825 .map_lookup_batch = generic_map_lookup_batch,
826 .map_update_batch = generic_map_update_batch,
827 .map_set_for_each_callback_args = map_set_for_each_callback_args,
828 .map_for_each_callback = bpf_for_each_array_elem,
829 .map_mem_usage = array_map_mem_usage,
830 .map_btf_id = &array_map_btf_ids[0],
831 .iter_seq_info = &iter_seq_info,
832};
833
834static int fd_array_map_alloc_check(union bpf_attr *attr)
835{
836 /* only file descriptors can be stored in this type of map */
837 if (attr->value_size != sizeof(u32))
838 return -EINVAL;
839 /* Program read-only/write-only not supported for special maps yet. */
840 if (attr->map_flags & (BPF_F_RDONLY_PROG | BPF_F_WRONLY_PROG))
841 return -EINVAL;
842 return array_map_alloc_check(attr);
843}
844
845static void fd_array_map_free(struct bpf_map *map)
846{
847 struct bpf_array *array = container_of(map, struct bpf_array, map);
848 int i;
849
850 /* make sure it's empty */
851 for (i = 0; i < array->map.max_entries; i++)
852 BUG_ON(array->ptrs[i] != NULL);
853
854 bpf_map_area_free(base: array);
855}
856
857static void *fd_array_map_lookup_elem(struct bpf_map *map, void *key)
858{
859 return ERR_PTR(error: -EOPNOTSUPP);
860}
861
862/* only called from syscall */
863int bpf_fd_array_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
864{
865 void **elem, *ptr;
866 int ret = 0;
867
868 if (!map->ops->map_fd_sys_lookup_elem)
869 return -ENOTSUPP;
870
871 rcu_read_lock();
872 elem = array_map_lookup_elem(map, key);
873 if (elem && (ptr = READ_ONCE(*elem)))
874 *value = map->ops->map_fd_sys_lookup_elem(ptr);
875 else
876 ret = -ENOENT;
877 rcu_read_unlock();
878
879 return ret;
880}
881
882/* only called from syscall */
883int bpf_fd_array_map_update_elem(struct bpf_map *map, struct file *map_file,
884 void *key, void *value, u64 map_flags)
885{
886 struct bpf_array *array = container_of(map, struct bpf_array, map);
887 void *new_ptr, *old_ptr;
888 u32 index = *(u32 *)key, ufd;
889
890 if (map_flags != BPF_ANY)
891 return -EINVAL;
892
893 if (index >= array->map.max_entries)
894 return -E2BIG;
895
896 ufd = *(u32 *)value;
897 new_ptr = map->ops->map_fd_get_ptr(map, map_file, ufd);
898 if (IS_ERR(ptr: new_ptr))
899 return PTR_ERR(ptr: new_ptr);
900
901 if (map->ops->map_poke_run) {
902 mutex_lock(&array->aux->poke_mutex);
903 old_ptr = xchg(array->ptrs + index, new_ptr);
904 map->ops->map_poke_run(map, index, old_ptr, new_ptr);
905 mutex_unlock(lock: &array->aux->poke_mutex);
906 } else {
907 old_ptr = xchg(array->ptrs + index, new_ptr);
908 }
909
910 if (old_ptr)
911 map->ops->map_fd_put_ptr(map, old_ptr, true);
912 return 0;
913}
914
915static long __fd_array_map_delete_elem(struct bpf_map *map, void *key, bool need_defer)
916{
917 struct bpf_array *array = container_of(map, struct bpf_array, map);
918 void *old_ptr;
919 u32 index = *(u32 *)key;
920
921 if (index >= array->map.max_entries)
922 return -E2BIG;
923
924 if (map->ops->map_poke_run) {
925 mutex_lock(&array->aux->poke_mutex);
926 old_ptr = xchg(array->ptrs + index, NULL);
927 map->ops->map_poke_run(map, index, old_ptr, NULL);
928 mutex_unlock(lock: &array->aux->poke_mutex);
929 } else {
930 old_ptr = xchg(array->ptrs + index, NULL);
931 }
932
933 if (old_ptr) {
934 map->ops->map_fd_put_ptr(map, old_ptr, need_defer);
935 return 0;
936 } else {
937 return -ENOENT;
938 }
939}
940
941static long fd_array_map_delete_elem(struct bpf_map *map, void *key)
942{
943 return __fd_array_map_delete_elem(map, key, need_defer: true);
944}
945
946static void *prog_fd_array_get_ptr(struct bpf_map *map,
947 struct file *map_file, int fd)
948{
949 struct bpf_prog *prog = bpf_prog_get(ufd: fd);
950 bool is_extended;
951
952 if (IS_ERR(ptr: prog))
953 return prog;
954
955 if (prog->type == BPF_PROG_TYPE_EXT ||
956 !bpf_prog_map_compatible(map, fp: prog)) {
957 bpf_prog_put(prog);
958 return ERR_PTR(error: -EINVAL);
959 }
960
961 mutex_lock(&prog->aux->ext_mutex);
962 is_extended = prog->aux->is_extended;
963 if (!is_extended)
964 prog->aux->prog_array_member_cnt++;
965 mutex_unlock(lock: &prog->aux->ext_mutex);
966 if (is_extended) {
967 /* Extended prog can not be tail callee. It's to prevent a
968 * potential infinite loop like:
969 * tail callee prog entry -> tail callee prog subprog ->
970 * freplace prog entry --tailcall-> tail callee prog entry.
971 */
972 bpf_prog_put(prog);
973 return ERR_PTR(error: -EBUSY);
974 }
975
976 return prog;
977}
978
979static void prog_fd_array_put_ptr(struct bpf_map *map, void *ptr, bool need_defer)
980{
981 struct bpf_prog *prog = ptr;
982
983 mutex_lock(&prog->aux->ext_mutex);
984 prog->aux->prog_array_member_cnt--;
985 mutex_unlock(lock: &prog->aux->ext_mutex);
986 /* bpf_prog is freed after one RCU or tasks trace grace period */
987 bpf_prog_put(prog);
988}
989
990static u32 prog_fd_array_sys_lookup_elem(void *ptr)
991{
992 return ((struct bpf_prog *)ptr)->aux->id;
993}
994
995/* decrement refcnt of all bpf_progs that are stored in this map */
996static void bpf_fd_array_map_clear(struct bpf_map *map, bool need_defer)
997{
998 struct bpf_array *array = container_of(map, struct bpf_array, map);
999 int i;
1000
1001 for (i = 0; i < array->map.max_entries; i++)
1002 __fd_array_map_delete_elem(map, key: &i, need_defer);
1003}
1004
1005static void prog_array_map_seq_show_elem(struct bpf_map *map, void *key,
1006 struct seq_file *m)
1007{
1008 void **elem, *ptr;
1009 u32 prog_id;
1010
1011 rcu_read_lock();
1012
1013 elem = array_map_lookup_elem(map, key);
1014 if (elem) {
1015 ptr = READ_ONCE(*elem);
1016 if (ptr) {
1017 seq_printf(m, fmt: "%u: ", *(u32 *)key);
1018 prog_id = prog_fd_array_sys_lookup_elem(ptr);
1019 btf_type_seq_show(btf: map->btf, type_id: map->btf_value_type_id,
1020 obj: &prog_id, m);
1021 seq_putc(m, c: '\n');
1022 }
1023 }
1024
1025 rcu_read_unlock();
1026}
1027
1028struct prog_poke_elem {
1029 struct list_head list;
1030 struct bpf_prog_aux *aux;
1031};
1032
1033static int prog_array_map_poke_track(struct bpf_map *map,
1034 struct bpf_prog_aux *prog_aux)
1035{
1036 struct prog_poke_elem *elem;
1037 struct bpf_array_aux *aux;
1038 int ret = 0;
1039
1040 aux = container_of(map, struct bpf_array, map)->aux;
1041 mutex_lock(&aux->poke_mutex);
1042 list_for_each_entry(elem, &aux->poke_progs, list) {
1043 if (elem->aux == prog_aux)
1044 goto out;
1045 }
1046
1047 elem = kmalloc(sizeof(*elem), GFP_KERNEL);
1048 if (!elem) {
1049 ret = -ENOMEM;
1050 goto out;
1051 }
1052
1053 INIT_LIST_HEAD(list: &elem->list);
1054 /* We must track the program's aux info at this point in time
1055 * since the program pointer itself may not be stable yet, see
1056 * also comment in prog_array_map_poke_run().
1057 */
1058 elem->aux = prog_aux;
1059
1060 list_add_tail(new: &elem->list, head: &aux->poke_progs);
1061out:
1062 mutex_unlock(lock: &aux->poke_mutex);
1063 return ret;
1064}
1065
1066static void prog_array_map_poke_untrack(struct bpf_map *map,
1067 struct bpf_prog_aux *prog_aux)
1068{
1069 struct prog_poke_elem *elem, *tmp;
1070 struct bpf_array_aux *aux;
1071
1072 aux = container_of(map, struct bpf_array, map)->aux;
1073 mutex_lock(&aux->poke_mutex);
1074 list_for_each_entry_safe(elem, tmp, &aux->poke_progs, list) {
1075 if (elem->aux == prog_aux) {
1076 list_del_init(entry: &elem->list);
1077 kfree(objp: elem);
1078 break;
1079 }
1080 }
1081 mutex_unlock(lock: &aux->poke_mutex);
1082}
1083
1084void __weak bpf_arch_poke_desc_update(struct bpf_jit_poke_descriptor *poke,
1085 struct bpf_prog *new, struct bpf_prog *old)
1086{
1087 WARN_ON_ONCE(1);
1088}
1089
1090static void prog_array_map_poke_run(struct bpf_map *map, u32 key,
1091 struct bpf_prog *old,
1092 struct bpf_prog *new)
1093{
1094 struct prog_poke_elem *elem;
1095 struct bpf_array_aux *aux;
1096
1097 aux = container_of(map, struct bpf_array, map)->aux;
1098 WARN_ON_ONCE(!mutex_is_locked(&aux->poke_mutex));
1099
1100 list_for_each_entry(elem, &aux->poke_progs, list) {
1101 struct bpf_jit_poke_descriptor *poke;
1102 int i;
1103
1104 for (i = 0; i < elem->aux->size_poke_tab; i++) {
1105 poke = &elem->aux->poke_tab[i];
1106
1107 /* Few things to be aware of:
1108 *
1109 * 1) We can only ever access aux in this context, but
1110 * not aux->prog since it might not be stable yet and
1111 * there could be danger of use after free otherwise.
1112 * 2) Initially when we start tracking aux, the program
1113 * is not JITed yet and also does not have a kallsyms
1114 * entry. We skip these as poke->tailcall_target_stable
1115 * is not active yet. The JIT will do the final fixup
1116 * before setting it stable. The various
1117 * poke->tailcall_target_stable are successively
1118 * activated, so tail call updates can arrive from here
1119 * while JIT is still finishing its final fixup for
1120 * non-activated poke entries.
1121 * 3) Also programs reaching refcount of zero while patching
1122 * is in progress is okay since we're protected under
1123 * poke_mutex and untrack the programs before the JIT
1124 * buffer is freed.
1125 */
1126 if (!READ_ONCE(poke->tailcall_target_stable))
1127 continue;
1128 if (poke->reason != BPF_POKE_REASON_TAIL_CALL)
1129 continue;
1130 if (poke->tail_call.map != map ||
1131 poke->tail_call.key != key)
1132 continue;
1133
1134 bpf_arch_poke_desc_update(poke, new, old);
1135 }
1136 }
1137}
1138
1139static void prog_array_map_clear_deferred(struct work_struct *work)
1140{
1141 struct bpf_map *map = container_of(work, struct bpf_array_aux,
1142 work)->map;
1143 bpf_fd_array_map_clear(map, need_defer: true);
1144 bpf_map_put(map);
1145}
1146
1147static void prog_array_map_clear(struct bpf_map *map)
1148{
1149 struct bpf_array_aux *aux = container_of(map, struct bpf_array,
1150 map)->aux;
1151 bpf_map_inc(map);
1152 schedule_work(work: &aux->work);
1153}
1154
1155static struct bpf_map *prog_array_map_alloc(union bpf_attr *attr)
1156{
1157 struct bpf_array_aux *aux;
1158 struct bpf_map *map;
1159
1160 aux = kzalloc(sizeof(*aux), GFP_KERNEL_ACCOUNT);
1161 if (!aux)
1162 return ERR_PTR(error: -ENOMEM);
1163
1164 INIT_WORK(&aux->work, prog_array_map_clear_deferred);
1165 INIT_LIST_HEAD(list: &aux->poke_progs);
1166 mutex_init(&aux->poke_mutex);
1167
1168 map = array_map_alloc(attr);
1169 if (IS_ERR(ptr: map)) {
1170 kfree(objp: aux);
1171 return map;
1172 }
1173
1174 container_of(map, struct bpf_array, map)->aux = aux;
1175 aux->map = map;
1176
1177 return map;
1178}
1179
1180static void prog_array_map_free(struct bpf_map *map)
1181{
1182 struct prog_poke_elem *elem, *tmp;
1183 struct bpf_array_aux *aux;
1184
1185 aux = container_of(map, struct bpf_array, map)->aux;
1186 list_for_each_entry_safe(elem, tmp, &aux->poke_progs, list) {
1187 list_del_init(entry: &elem->list);
1188 kfree(objp: elem);
1189 }
1190 kfree(objp: aux);
1191 fd_array_map_free(map);
1192}
1193
1194/* prog_array->aux->{type,jited} is a runtime binding.
1195 * Doing static check alone in the verifier is not enough.
1196 * Thus, prog_array_map cannot be used as an inner_map
1197 * and map_meta_equal is not implemented.
1198 */
1199const struct bpf_map_ops prog_array_map_ops = {
1200 .map_alloc_check = fd_array_map_alloc_check,
1201 .map_alloc = prog_array_map_alloc,
1202 .map_free = prog_array_map_free,
1203 .map_poke_track = prog_array_map_poke_track,
1204 .map_poke_untrack = prog_array_map_poke_untrack,
1205 .map_poke_run = prog_array_map_poke_run,
1206 .map_get_next_key = bpf_array_get_next_key,
1207 .map_lookup_elem = fd_array_map_lookup_elem,
1208 .map_delete_elem = fd_array_map_delete_elem,
1209 .map_fd_get_ptr = prog_fd_array_get_ptr,
1210 .map_fd_put_ptr = prog_fd_array_put_ptr,
1211 .map_fd_sys_lookup_elem = prog_fd_array_sys_lookup_elem,
1212 .map_release_uref = prog_array_map_clear,
1213 .map_seq_show_elem = prog_array_map_seq_show_elem,
1214 .map_mem_usage = array_map_mem_usage,
1215 .map_btf_id = &array_map_btf_ids[0],
1216};
1217
1218static struct bpf_event_entry *bpf_event_entry_gen(struct file *perf_file,
1219 struct file *map_file)
1220{
1221 struct bpf_event_entry *ee;
1222
1223 ee = kzalloc(sizeof(*ee), GFP_KERNEL);
1224 if (ee) {
1225 ee->event = perf_file->private_data;
1226 ee->perf_file = perf_file;
1227 ee->map_file = map_file;
1228 }
1229
1230 return ee;
1231}
1232
1233static void __bpf_event_entry_free(struct rcu_head *rcu)
1234{
1235 struct bpf_event_entry *ee;
1236
1237 ee = container_of(rcu, struct bpf_event_entry, rcu);
1238 fput(ee->perf_file);
1239 kfree(objp: ee);
1240}
1241
1242static void bpf_event_entry_free_rcu(struct bpf_event_entry *ee)
1243{
1244 call_rcu(head: &ee->rcu, func: __bpf_event_entry_free);
1245}
1246
1247static void *perf_event_fd_array_get_ptr(struct bpf_map *map,
1248 struct file *map_file, int fd)
1249{
1250 struct bpf_event_entry *ee;
1251 struct perf_event *event;
1252 struct file *perf_file;
1253 u64 value;
1254
1255 perf_file = perf_event_get(fd);
1256 if (IS_ERR(ptr: perf_file))
1257 return perf_file;
1258
1259 ee = ERR_PTR(error: -EOPNOTSUPP);
1260 event = perf_file->private_data;
1261 if (perf_event_read_local(event, value: &value, NULL, NULL) == -EOPNOTSUPP)
1262 goto err_out;
1263
1264 ee = bpf_event_entry_gen(perf_file, map_file);
1265 if (ee)
1266 return ee;
1267 ee = ERR_PTR(error: -ENOMEM);
1268err_out:
1269 fput(perf_file);
1270 return ee;
1271}
1272
1273static void perf_event_fd_array_put_ptr(struct bpf_map *map, void *ptr, bool need_defer)
1274{
1275 /* bpf_perf_event is freed after one RCU grace period */
1276 bpf_event_entry_free_rcu(ee: ptr);
1277}
1278
1279static void perf_event_fd_array_release(struct bpf_map *map,
1280 struct file *map_file)
1281{
1282 struct bpf_array *array = container_of(map, struct bpf_array, map);
1283 struct bpf_event_entry *ee;
1284 int i;
1285
1286 if (map->map_flags & BPF_F_PRESERVE_ELEMS)
1287 return;
1288
1289 rcu_read_lock();
1290 for (i = 0; i < array->map.max_entries; i++) {
1291 ee = READ_ONCE(array->ptrs[i]);
1292 if (ee && ee->map_file == map_file)
1293 __fd_array_map_delete_elem(map, key: &i, need_defer: true);
1294 }
1295 rcu_read_unlock();
1296}
1297
1298static void perf_event_fd_array_map_free(struct bpf_map *map)
1299{
1300 if (map->map_flags & BPF_F_PRESERVE_ELEMS)
1301 bpf_fd_array_map_clear(map, need_defer: false);
1302 fd_array_map_free(map);
1303}
1304
1305const struct bpf_map_ops perf_event_array_map_ops = {
1306 .map_meta_equal = bpf_map_meta_equal,
1307 .map_alloc_check = fd_array_map_alloc_check,
1308 .map_alloc = array_map_alloc,
1309 .map_free = perf_event_fd_array_map_free,
1310 .map_get_next_key = bpf_array_get_next_key,
1311 .map_lookup_elem = fd_array_map_lookup_elem,
1312 .map_delete_elem = fd_array_map_delete_elem,
1313 .map_fd_get_ptr = perf_event_fd_array_get_ptr,
1314 .map_fd_put_ptr = perf_event_fd_array_put_ptr,
1315 .map_release = perf_event_fd_array_release,
1316 .map_check_btf = map_check_no_btf,
1317 .map_mem_usage = array_map_mem_usage,
1318 .map_btf_id = &array_map_btf_ids[0],
1319};
1320
1321#ifdef CONFIG_CGROUPS
1322static void *cgroup_fd_array_get_ptr(struct bpf_map *map,
1323 struct file *map_file /* not used */,
1324 int fd)
1325{
1326 return cgroup_get_from_fd(fd);
1327}
1328
1329static void cgroup_fd_array_put_ptr(struct bpf_map *map, void *ptr, bool need_defer)
1330{
1331 /* cgroup_put free cgrp after a rcu grace period */
1332 cgroup_put(cgrp: ptr);
1333}
1334
1335static void cgroup_fd_array_free(struct bpf_map *map)
1336{
1337 bpf_fd_array_map_clear(map, need_defer: false);
1338 fd_array_map_free(map);
1339}
1340
1341const struct bpf_map_ops cgroup_array_map_ops = {
1342 .map_meta_equal = bpf_map_meta_equal,
1343 .map_alloc_check = fd_array_map_alloc_check,
1344 .map_alloc = array_map_alloc,
1345 .map_free = cgroup_fd_array_free,
1346 .map_get_next_key = bpf_array_get_next_key,
1347 .map_lookup_elem = fd_array_map_lookup_elem,
1348 .map_delete_elem = fd_array_map_delete_elem,
1349 .map_fd_get_ptr = cgroup_fd_array_get_ptr,
1350 .map_fd_put_ptr = cgroup_fd_array_put_ptr,
1351 .map_check_btf = map_check_no_btf,
1352 .map_mem_usage = array_map_mem_usage,
1353 .map_btf_id = &array_map_btf_ids[0],
1354};
1355#endif
1356
1357static struct bpf_map *array_of_map_alloc(union bpf_attr *attr)
1358{
1359 struct bpf_map *map, *inner_map_meta;
1360
1361 inner_map_meta = bpf_map_meta_alloc(inner_map_ufd: attr->inner_map_fd);
1362 if (IS_ERR(ptr: inner_map_meta))
1363 return inner_map_meta;
1364
1365 map = array_map_alloc(attr);
1366 if (IS_ERR(ptr: map)) {
1367 bpf_map_meta_free(map_meta: inner_map_meta);
1368 return map;
1369 }
1370
1371 map->inner_map_meta = inner_map_meta;
1372
1373 return map;
1374}
1375
1376static void array_of_map_free(struct bpf_map *map)
1377{
1378 /* map->inner_map_meta is only accessed by syscall which
1379 * is protected by fdget/fdput.
1380 */
1381 bpf_map_meta_free(map_meta: map->inner_map_meta);
1382 bpf_fd_array_map_clear(map, need_defer: false);
1383 fd_array_map_free(map);
1384}
1385
1386static void *array_of_map_lookup_elem(struct bpf_map *map, void *key)
1387{
1388 struct bpf_map **inner_map = array_map_lookup_elem(map, key);
1389
1390 if (!inner_map)
1391 return NULL;
1392
1393 return READ_ONCE(*inner_map);
1394}
1395
1396static int array_of_map_gen_lookup(struct bpf_map *map,
1397 struct bpf_insn *insn_buf)
1398{
1399 struct bpf_array *array = container_of(map, struct bpf_array, map);
1400 u32 elem_size = array->elem_size;
1401 struct bpf_insn *insn = insn_buf;
1402 const int ret = BPF_REG_0;
1403 const int map_ptr = BPF_REG_1;
1404 const int index = BPF_REG_2;
1405
1406 *insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
1407 *insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
1408 if (!map->bypass_spec_v1) {
1409 *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 6);
1410 *insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
1411 } else {
1412 *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 5);
1413 }
1414 if (is_power_of_2(n: elem_size))
1415 *insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(elem_size));
1416 else
1417 *insn++ = BPF_ALU64_IMM(BPF_MUL, ret, elem_size);
1418 *insn++ = BPF_ALU64_REG(BPF_ADD, ret, map_ptr);
1419 *insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0);
1420 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1);
1421 *insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
1422 *insn++ = BPF_MOV64_IMM(ret, 0);
1423
1424 return insn - insn_buf;
1425}
1426
1427const struct bpf_map_ops array_of_maps_map_ops = {
1428 .map_alloc_check = fd_array_map_alloc_check,
1429 .map_alloc = array_of_map_alloc,
1430 .map_free = array_of_map_free,
1431 .map_get_next_key = bpf_array_get_next_key,
1432 .map_lookup_elem = array_of_map_lookup_elem,
1433 .map_delete_elem = fd_array_map_delete_elem,
1434 .map_fd_get_ptr = bpf_map_fd_get_ptr,
1435 .map_fd_put_ptr = bpf_map_fd_put_ptr,
1436 .map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
1437 .map_gen_lookup = array_of_map_gen_lookup,
1438 .map_lookup_batch = generic_map_lookup_batch,
1439 .map_update_batch = generic_map_update_batch,
1440 .map_check_btf = map_check_no_btf,
1441 .map_mem_usage = array_map_mem_usage,
1442 .map_btf_id = &array_map_btf_ids[0],
1443};
1444

source code of linux/kernel/bpf/arraymap.c