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
16#include "map_in_map.h"
17
18#define ARRAY_CREATE_FLAG_MASK \
19 (BPF_F_NUMA_NODE | BPF_F_MMAPABLE | BPF_F_ACCESS_MASK | \
20 BPF_F_PRESERVE_ELEMS | BPF_F_INNER_MAP)
21
22static void bpf_array_free_percpu(struct bpf_array *array)
23{
24 int i;
25
26 for (i = 0; i < array->map.max_entries; i++) {
27 free_percpu(pdata: array->pptrs[i]);
28 cond_resched();
29 }
30}
31
32static int bpf_array_alloc_percpu(struct bpf_array *array)
33{
34 void __percpu *ptr;
35 int i;
36
37 for (i = 0; i < array->map.max_entries; i++) {
38 ptr = bpf_map_alloc_percpu(map: &array->map, size: array->elem_size, align: 8,
39 GFP_USER | __GFP_NOWARN);
40 if (!ptr) {
41 bpf_array_free_percpu(array);
42 return -ENOMEM;
43 }
44 array->pptrs[i] = ptr;
45 cond_resched();
46 }
47
48 return 0;
49}
50
51/* Called from syscall */
52int array_map_alloc_check(union bpf_attr *attr)
53{
54 bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
55 int numa_node = bpf_map_attr_numa_node(attr);
56
57 /* check sanity of attributes */
58 if (attr->max_entries == 0 || attr->key_size != 4 ||
59 attr->value_size == 0 ||
60 attr->map_flags & ~ARRAY_CREATE_FLAG_MASK ||
61 !bpf_map_flags_access_ok(access_flags: attr->map_flags) ||
62 (percpu && numa_node != NUMA_NO_NODE))
63 return -EINVAL;
64
65 if (attr->map_type != BPF_MAP_TYPE_ARRAY &&
66 attr->map_flags & (BPF_F_MMAPABLE | BPF_F_INNER_MAP))
67 return -EINVAL;
68
69 if (attr->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY &&
70 attr->map_flags & BPF_F_PRESERVE_ELEMS)
71 return -EINVAL;
72
73 /* avoid overflow on round_up(map->value_size) */
74 if (attr->value_size > INT_MAX)
75 return -E2BIG;
76
77 return 0;
78}
79
80static struct bpf_map *array_map_alloc(union bpf_attr *attr)
81{
82 bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
83 int numa_node = bpf_map_attr_numa_node(attr);
84 u32 elem_size, index_mask, max_entries;
85 bool bypass_spec_v1 = bpf_bypass_spec_v1();
86 u64 array_size, mask64;
87 struct bpf_array *array;
88
89 elem_size = round_up(attr->value_size, 8);
90
91 max_entries = attr->max_entries;
92
93 /* On 32 bit archs roundup_pow_of_two() with max_entries that has
94 * upper most bit set in u32 space is undefined behavior due to
95 * resulting 1U << 32, so do it manually here in u64 space.
96 */
97 mask64 = fls_long(l: max_entries - 1);
98 mask64 = 1ULL << mask64;
99 mask64 -= 1;
100
101 index_mask = mask64;
102 if (!bypass_spec_v1) {
103 /* round up array size to nearest power of 2,
104 * since cpu will speculate within index_mask limits
105 */
106 max_entries = index_mask + 1;
107 /* Check for overflows. */
108 if (max_entries < attr->max_entries)
109 return ERR_PTR(error: -E2BIG);
110 }
111
112 array_size = sizeof(*array);
113 if (percpu) {
114 array_size += (u64) max_entries * sizeof(void *);
115 } else {
116 /* rely on vmalloc() to return page-aligned memory and
117 * ensure array->value is exactly page-aligned
118 */
119 if (attr->map_flags & BPF_F_MMAPABLE) {
120 array_size = PAGE_ALIGN(array_size);
121 array_size += PAGE_ALIGN((u64) max_entries * elem_size);
122 } else {
123 array_size += (u64) max_entries * elem_size;
124 }
125 }
126
127 /* allocate all map elements and zero-initialize them */
128 if (attr->map_flags & BPF_F_MMAPABLE) {
129 void *data;
130
131 /* kmalloc'ed memory can't be mmap'ed, use explicit vmalloc */
132 data = bpf_map_area_mmapable_alloc(size: array_size, numa_node);
133 if (!data)
134 return ERR_PTR(error: -ENOMEM);
135 array = data + PAGE_ALIGN(sizeof(struct bpf_array))
136 - offsetof(struct bpf_array, value);
137 } else {
138 array = bpf_map_area_alloc(size: array_size, numa_node);
139 }
140 if (!array)
141 return ERR_PTR(error: -ENOMEM);
142 array->index_mask = index_mask;
143 array->map.bypass_spec_v1 = bypass_spec_v1;
144
145 /* copy mandatory map attributes */
146 bpf_map_init_from_attr(map: &array->map, attr);
147 array->elem_size = elem_size;
148
149 if (percpu && bpf_array_alloc_percpu(array)) {
150 bpf_map_area_free(base: array);
151 return ERR_PTR(error: -ENOMEM);
152 }
153
154 return &array->map;
155}
156
157static void *array_map_elem_ptr(struct bpf_array* array, u32 index)
158{
159 return array->value + (u64)array->elem_size * index;
160}
161
162/* Called from syscall or from eBPF program */
163static void *array_map_lookup_elem(struct bpf_map *map, void *key)
164{
165 struct bpf_array *array = container_of(map, struct bpf_array, map);
166 u32 index = *(u32 *)key;
167
168 if (unlikely(index >= array->map.max_entries))
169 return NULL;
170
171 return array->value + (u64)array->elem_size * (index & array->index_mask);
172}
173
174static int array_map_direct_value_addr(const struct bpf_map *map, u64 *imm,
175 u32 off)
176{
177 struct bpf_array *array = container_of(map, struct bpf_array, map);
178
179 if (map->max_entries != 1)
180 return -ENOTSUPP;
181 if (off >= map->value_size)
182 return -EINVAL;
183
184 *imm = (unsigned long)array->value;
185 return 0;
186}
187
188static int array_map_direct_value_meta(const struct bpf_map *map, u64 imm,
189 u32 *off)
190{
191 struct bpf_array *array = container_of(map, struct bpf_array, map);
192 u64 base = (unsigned long)array->value;
193 u64 range = array->elem_size;
194
195 if (map->max_entries != 1)
196 return -ENOTSUPP;
197 if (imm < base || imm >= base + range)
198 return -ENOENT;
199
200 *off = imm - base;
201 return 0;
202}
203
204/* emit BPF instructions equivalent to C code of array_map_lookup_elem() */
205static int array_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
206{
207 struct bpf_array *array = container_of(map, struct bpf_array, map);
208 struct bpf_insn *insn = insn_buf;
209 u32 elem_size = array->elem_size;
210 const int ret = BPF_REG_0;
211 const int map_ptr = BPF_REG_1;
212 const int index = BPF_REG_2;
213
214 if (map->map_flags & BPF_F_INNER_MAP)
215 return -EOPNOTSUPP;
216
217 *insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
218 *insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
219 if (!map->bypass_spec_v1) {
220 *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 4);
221 *insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
222 } else {
223 *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 3);
224 }
225
226 if (is_power_of_2(n: elem_size)) {
227 *insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(elem_size));
228 } else {
229 *insn++ = BPF_ALU64_IMM(BPF_MUL, ret, elem_size);
230 }
231 *insn++ = BPF_ALU64_REG(BPF_ADD, ret, map_ptr);
232 *insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
233 *insn++ = BPF_MOV64_IMM(ret, 0);
234 return insn - insn_buf;
235}
236
237/* Called from eBPF program */
238static void *percpu_array_map_lookup_elem(struct bpf_map *map, void *key)
239{
240 struct bpf_array *array = container_of(map, struct bpf_array, map);
241 u32 index = *(u32 *)key;
242
243 if (unlikely(index >= array->map.max_entries))
244 return NULL;
245
246 return this_cpu_ptr(array->pptrs[index & array->index_mask]);
247}
248
249static void *percpu_array_map_lookup_percpu_elem(struct bpf_map *map, void *key, u32 cpu)
250{
251 struct bpf_array *array = container_of(map, struct bpf_array, map);
252 u32 index = *(u32 *)key;
253
254 if (cpu >= nr_cpu_ids)
255 return NULL;
256
257 if (unlikely(index >= array->map.max_entries))
258 return NULL;
259
260 return per_cpu_ptr(array->pptrs[index & array->index_mask], cpu);
261}
262
263int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value)
264{
265 struct bpf_array *array = container_of(map, struct bpf_array, map);
266 u32 index = *(u32 *)key;
267 void __percpu *pptr;
268 int cpu, off = 0;
269 u32 size;
270
271 if (unlikely(index >= array->map.max_entries))
272 return -ENOENT;
273
274 /* per_cpu areas are zero-filled and bpf programs can only
275 * access 'value_size' of them, so copying rounded areas
276 * will not leak any kernel data
277 */
278 size = array->elem_size;
279 rcu_read_lock();
280 pptr = array->pptrs[index & array->index_mask];
281 for_each_possible_cpu(cpu) {
282 copy_map_value_long(map, dst: value + off, per_cpu_ptr(pptr, cpu));
283 check_and_init_map_value(map, dst: value + off);
284 off += size;
285 }
286 rcu_read_unlock();
287 return 0;
288}
289
290/* Called from syscall */
291static int array_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
292{
293 struct bpf_array *array = container_of(map, struct bpf_array, map);
294 u32 index = key ? *(u32 *)key : U32_MAX;
295 u32 *next = (u32 *)next_key;
296
297 if (index >= array->map.max_entries) {
298 *next = 0;
299 return 0;
300 }
301
302 if (index == array->map.max_entries - 1)
303 return -ENOENT;
304
305 *next = index + 1;
306 return 0;
307}
308
309/* Called from syscall or from eBPF program */
310static long array_map_update_elem(struct bpf_map *map, void *key, void *value,
311 u64 map_flags)
312{
313 struct bpf_array *array = container_of(map, struct bpf_array, map);
314 u32 index = *(u32 *)key;
315 char *val;
316
317 if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST))
318 /* unknown flags */
319 return -EINVAL;
320
321 if (unlikely(index >= array->map.max_entries))
322 /* all elements were pre-allocated, cannot insert a new one */
323 return -E2BIG;
324
325 if (unlikely(map_flags & BPF_NOEXIST))
326 /* all elements already exist */
327 return -EEXIST;
328
329 if (unlikely((map_flags & BPF_F_LOCK) &&
330 !btf_record_has_field(map->record, BPF_SPIN_LOCK)))
331 return -EINVAL;
332
333 if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
334 val = this_cpu_ptr(array->pptrs[index & array->index_mask]);
335 copy_map_value(map, dst: val, src: value);
336 bpf_obj_free_fields(rec: array->map.record, obj: val);
337 } else {
338 val = array->value +
339 (u64)array->elem_size * (index & array->index_mask);
340 if (map_flags & BPF_F_LOCK)
341 copy_map_value_locked(map, dst: val, src: value, lock_src: false);
342 else
343 copy_map_value(map, dst: val, src: value);
344 bpf_obj_free_fields(rec: array->map.record, obj: val);
345 }
346 return 0;
347}
348
349int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
350 u64 map_flags)
351{
352 struct bpf_array *array = container_of(map, struct bpf_array, map);
353 u32 index = *(u32 *)key;
354 void __percpu *pptr;
355 int cpu, off = 0;
356 u32 size;
357
358 if (unlikely(map_flags > BPF_EXIST))
359 /* unknown flags */
360 return -EINVAL;
361
362 if (unlikely(index >= array->map.max_entries))
363 /* all elements were pre-allocated, cannot insert a new one */
364 return -E2BIG;
365
366 if (unlikely(map_flags == BPF_NOEXIST))
367 /* all elements already exist */
368 return -EEXIST;
369
370 /* the user space will provide round_up(value_size, 8) bytes that
371 * will be copied into per-cpu area. bpf programs can only access
372 * value_size of it. During lookup the same extra bytes will be
373 * returned or zeros which were zero-filled by percpu_alloc,
374 * so no kernel data leaks possible
375 */
376 size = array->elem_size;
377 rcu_read_lock();
378 pptr = array->pptrs[index & array->index_mask];
379 for_each_possible_cpu(cpu) {
380 copy_map_value_long(map, per_cpu_ptr(pptr, cpu), src: value + off);
381 bpf_obj_free_fields(rec: array->map.record, per_cpu_ptr(pptr, cpu));
382 off += size;
383 }
384 rcu_read_unlock();
385 return 0;
386}
387
388/* Called from syscall or from eBPF program */
389static long array_map_delete_elem(struct bpf_map *map, void *key)
390{
391 return -EINVAL;
392}
393
394static void *array_map_vmalloc_addr(struct bpf_array *array)
395{
396 return (void *)round_down((unsigned long)array, PAGE_SIZE);
397}
398
399static void array_map_free_timers(struct bpf_map *map)
400{
401 struct bpf_array *array = container_of(map, struct bpf_array, map);
402 int i;
403
404 /* We don't reset or free fields other than timer on uref dropping to zero. */
405 if (!btf_record_has_field(rec: map->record, type: BPF_TIMER))
406 return;
407
408 for (i = 0; i < array->map.max_entries; i++)
409 bpf_obj_free_timer(rec: map->record, obj: array_map_elem_ptr(array, index: i));
410}
411
412/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
413static void array_map_free(struct bpf_map *map)
414{
415 struct bpf_array *array = container_of(map, struct bpf_array, map);
416 int i;
417
418 if (!IS_ERR_OR_NULL(ptr: map->record)) {
419 if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
420 for (i = 0; i < array->map.max_entries; i++) {
421 void __percpu *pptr = array->pptrs[i & array->index_mask];
422 int cpu;
423
424 for_each_possible_cpu(cpu) {
425 bpf_obj_free_fields(rec: map->record, per_cpu_ptr(pptr, cpu));
426 cond_resched();
427 }
428 }
429 } else {
430 for (i = 0; i < array->map.max_entries; i++)
431 bpf_obj_free_fields(rec: map->record, obj: array_map_elem_ptr(array, index: i));
432 }
433 }
434
435 if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
436 bpf_array_free_percpu(array);
437
438 if (array->map.map_flags & BPF_F_MMAPABLE)
439 bpf_map_area_free(base: array_map_vmalloc_addr(array));
440 else
441 bpf_map_area_free(base: array);
442}
443
444static void array_map_seq_show_elem(struct bpf_map *map, void *key,
445 struct seq_file *m)
446{
447 void *value;
448
449 rcu_read_lock();
450
451 value = array_map_lookup_elem(map, key);
452 if (!value) {
453 rcu_read_unlock();
454 return;
455 }
456
457 if (map->btf_key_type_id)
458 seq_printf(m, fmt: "%u: ", *(u32 *)key);
459 btf_type_seq_show(btf: map->btf, type_id: map->btf_value_type_id, obj: value, m);
460 seq_puts(m, s: "\n");
461
462 rcu_read_unlock();
463}
464
465static void percpu_array_map_seq_show_elem(struct bpf_map *map, void *key,
466 struct seq_file *m)
467{
468 struct bpf_array *array = container_of(map, struct bpf_array, map);
469 u32 index = *(u32 *)key;
470 void __percpu *pptr;
471 int cpu;
472
473 rcu_read_lock();
474
475 seq_printf(m, fmt: "%u: {\n", *(u32 *)key);
476 pptr = array->pptrs[index & array->index_mask];
477 for_each_possible_cpu(cpu) {
478 seq_printf(m, fmt: "\tcpu%d: ", cpu);
479 btf_type_seq_show(btf: map->btf, type_id: map->btf_value_type_id,
480 per_cpu_ptr(pptr, cpu), m);
481 seq_puts(m, s: "\n");
482 }
483 seq_puts(m, s: "}\n");
484
485 rcu_read_unlock();
486}
487
488static int array_map_check_btf(const struct bpf_map *map,
489 const struct btf *btf,
490 const struct btf_type *key_type,
491 const struct btf_type *value_type)
492{
493 u32 int_data;
494
495 /* One exception for keyless BTF: .bss/.data/.rodata map */
496 if (btf_type_is_void(t: key_type)) {
497 if (map->map_type != BPF_MAP_TYPE_ARRAY ||
498 map->max_entries != 1)
499 return -EINVAL;
500
501 if (BTF_INFO_KIND(value_type->info) != BTF_KIND_DATASEC)
502 return -EINVAL;
503
504 return 0;
505 }
506
507 if (BTF_INFO_KIND(key_type->info) != BTF_KIND_INT)
508 return -EINVAL;
509
510 int_data = *(u32 *)(key_type + 1);
511 /* bpf array can only take a u32 key. This check makes sure
512 * that the btf matches the attr used during map_create.
513 */
514 if (BTF_INT_BITS(int_data) != 32 || BTF_INT_OFFSET(int_data))
515 return -EINVAL;
516
517 return 0;
518}
519
520static int array_map_mmap(struct bpf_map *map, struct vm_area_struct *vma)
521{
522 struct bpf_array *array = container_of(map, struct bpf_array, map);
523 pgoff_t pgoff = PAGE_ALIGN(sizeof(*array)) >> PAGE_SHIFT;
524
525 if (!(map->map_flags & BPF_F_MMAPABLE))
526 return -EINVAL;
527
528 if (vma->vm_pgoff * PAGE_SIZE + (vma->vm_end - vma->vm_start) >
529 PAGE_ALIGN((u64)array->map.max_entries * array->elem_size))
530 return -EINVAL;
531
532 return remap_vmalloc_range(vma, addr: array_map_vmalloc_addr(array),
533 pgoff: vma->vm_pgoff + pgoff);
534}
535
536static bool array_map_meta_equal(const struct bpf_map *meta0,
537 const struct bpf_map *meta1)
538{
539 if (!bpf_map_meta_equal(meta0, meta1))
540 return false;
541 return meta0->map_flags & BPF_F_INNER_MAP ? true :
542 meta0->max_entries == meta1->max_entries;
543}
544
545struct bpf_iter_seq_array_map_info {
546 struct bpf_map *map;
547 void *percpu_value_buf;
548 u32 index;
549};
550
551static void *bpf_array_map_seq_start(struct seq_file *seq, loff_t *pos)
552{
553 struct bpf_iter_seq_array_map_info *info = seq->private;
554 struct bpf_map *map = info->map;
555 struct bpf_array *array;
556 u32 index;
557
558 if (info->index >= map->max_entries)
559 return NULL;
560
561 if (*pos == 0)
562 ++*pos;
563 array = container_of(map, struct bpf_array, map);
564 index = info->index & array->index_mask;
565 if (info->percpu_value_buf)
566 return array->pptrs[index];
567 return array_map_elem_ptr(array, index);
568}
569
570static void *bpf_array_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
571{
572 struct bpf_iter_seq_array_map_info *info = seq->private;
573 struct bpf_map *map = info->map;
574 struct bpf_array *array;
575 u32 index;
576
577 ++*pos;
578 ++info->index;
579 if (info->index >= map->max_entries)
580 return NULL;
581
582 array = container_of(map, struct bpf_array, map);
583 index = info->index & array->index_mask;
584 if (info->percpu_value_buf)
585 return array->pptrs[index];
586 return array_map_elem_ptr(array, index);
587}
588
589static int __bpf_array_map_seq_show(struct seq_file *seq, void *v)
590{
591 struct bpf_iter_seq_array_map_info *info = seq->private;
592 struct bpf_iter__bpf_map_elem ctx = {};
593 struct bpf_map *map = info->map;
594 struct bpf_array *array = container_of(map, struct bpf_array, map);
595 struct bpf_iter_meta meta;
596 struct bpf_prog *prog;
597 int off = 0, cpu = 0;
598 void __percpu **pptr;
599 u32 size;
600
601 meta.seq = seq;
602 prog = bpf_iter_get_info(meta: &meta, in_stop: v == NULL);
603 if (!prog)
604 return 0;
605
606 ctx.meta = &meta;
607 ctx.map = info->map;
608 if (v) {
609 ctx.key = &info->index;
610
611 if (!info->percpu_value_buf) {
612 ctx.value = v;
613 } else {
614 pptr = v;
615 size = array->elem_size;
616 for_each_possible_cpu(cpu) {
617 copy_map_value_long(map, dst: info->percpu_value_buf + off,
618 per_cpu_ptr(pptr, cpu));
619 check_and_init_map_value(map, dst: info->percpu_value_buf + off);
620 off += size;
621 }
622 ctx.value = info->percpu_value_buf;
623 }
624 }
625
626 return bpf_iter_run_prog(prog, ctx: &ctx);
627}
628
629static int bpf_array_map_seq_show(struct seq_file *seq, void *v)
630{
631 return __bpf_array_map_seq_show(seq, v);
632}
633
634static void bpf_array_map_seq_stop(struct seq_file *seq, void *v)
635{
636 if (!v)
637 (void)__bpf_array_map_seq_show(seq, NULL);
638}
639
640static int bpf_iter_init_array_map(void *priv_data,
641 struct bpf_iter_aux_info *aux)
642{
643 struct bpf_iter_seq_array_map_info *seq_info = priv_data;
644 struct bpf_map *map = aux->map;
645 struct bpf_array *array = container_of(map, struct bpf_array, map);
646 void *value_buf;
647 u32 buf_size;
648
649 if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
650 buf_size = array->elem_size * num_possible_cpus();
651 value_buf = kmalloc(size: buf_size, GFP_USER | __GFP_NOWARN);
652 if (!value_buf)
653 return -ENOMEM;
654
655 seq_info->percpu_value_buf = value_buf;
656 }
657
658 /* bpf_iter_attach_map() acquires a map uref, and the uref may be
659 * released before or in the middle of iterating map elements, so
660 * acquire an extra map uref for iterator.
661 */
662 bpf_map_inc_with_uref(map);
663 seq_info->map = map;
664 return 0;
665}
666
667static void bpf_iter_fini_array_map(void *priv_data)
668{
669 struct bpf_iter_seq_array_map_info *seq_info = priv_data;
670
671 bpf_map_put_with_uref(map: seq_info->map);
672 kfree(objp: seq_info->percpu_value_buf);
673}
674
675static const struct seq_operations bpf_array_map_seq_ops = {
676 .start = bpf_array_map_seq_start,
677 .next = bpf_array_map_seq_next,
678 .stop = bpf_array_map_seq_stop,
679 .show = bpf_array_map_seq_show,
680};
681
682static const struct bpf_iter_seq_info iter_seq_info = {
683 .seq_ops = &bpf_array_map_seq_ops,
684 .init_seq_private = bpf_iter_init_array_map,
685 .fini_seq_private = bpf_iter_fini_array_map,
686 .seq_priv_size = sizeof(struct bpf_iter_seq_array_map_info),
687};
688
689static long bpf_for_each_array_elem(struct bpf_map *map, bpf_callback_t callback_fn,
690 void *callback_ctx, u64 flags)
691{
692 u32 i, key, num_elems = 0;
693 struct bpf_array *array;
694 bool is_percpu;
695 u64 ret = 0;
696 void *val;
697
698 if (flags != 0)
699 return -EINVAL;
700
701 is_percpu = map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
702 array = container_of(map, struct bpf_array, map);
703 if (is_percpu)
704 migrate_disable();
705 for (i = 0; i < map->max_entries; i++) {
706 if (is_percpu)
707 val = this_cpu_ptr(array->pptrs[i]);
708 else
709 val = array_map_elem_ptr(array, index: i);
710 num_elems++;
711 key = i;
712 ret = callback_fn((u64)(long)map, (u64)(long)&key,
713 (u64)(long)val, (u64)(long)callback_ctx, 0);
714 /* return value: 0 - continue, 1 - stop and return */
715 if (ret)
716 break;
717 }
718
719 if (is_percpu)
720 migrate_enable();
721 return num_elems;
722}
723
724static u64 array_map_mem_usage(const struct bpf_map *map)
725{
726 struct bpf_array *array = container_of(map, struct bpf_array, map);
727 bool percpu = map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
728 u32 elem_size = array->elem_size;
729 u64 entries = map->max_entries;
730 u64 usage = sizeof(*array);
731
732 if (percpu) {
733 usage += entries * sizeof(void *);
734 usage += entries * elem_size * num_possible_cpus();
735 } else {
736 if (map->map_flags & BPF_F_MMAPABLE) {
737 usage = PAGE_ALIGN(usage);
738 usage += PAGE_ALIGN(entries * elem_size);
739 } else {
740 usage += entries * elem_size;
741 }
742 }
743 return usage;
744}
745
746BTF_ID_LIST_SINGLE(array_map_btf_ids, struct, bpf_array)
747const struct bpf_map_ops array_map_ops = {
748 .map_meta_equal = array_map_meta_equal,
749 .map_alloc_check = array_map_alloc_check,
750 .map_alloc = array_map_alloc,
751 .map_free = array_map_free,
752 .map_get_next_key = array_map_get_next_key,
753 .map_release_uref = array_map_free_timers,
754 .map_lookup_elem = array_map_lookup_elem,
755 .map_update_elem = array_map_update_elem,
756 .map_delete_elem = array_map_delete_elem,
757 .map_gen_lookup = array_map_gen_lookup,
758 .map_direct_value_addr = array_map_direct_value_addr,
759 .map_direct_value_meta = array_map_direct_value_meta,
760 .map_mmap = array_map_mmap,
761 .map_seq_show_elem = array_map_seq_show_elem,
762 .map_check_btf = array_map_check_btf,
763 .map_lookup_batch = generic_map_lookup_batch,
764 .map_update_batch = generic_map_update_batch,
765 .map_set_for_each_callback_args = map_set_for_each_callback_args,
766 .map_for_each_callback = bpf_for_each_array_elem,
767 .map_mem_usage = array_map_mem_usage,
768 .map_btf_id = &array_map_btf_ids[0],
769 .iter_seq_info = &iter_seq_info,
770};
771
772const struct bpf_map_ops percpu_array_map_ops = {
773 .map_meta_equal = bpf_map_meta_equal,
774 .map_alloc_check = array_map_alloc_check,
775 .map_alloc = array_map_alloc,
776 .map_free = array_map_free,
777 .map_get_next_key = array_map_get_next_key,
778 .map_lookup_elem = percpu_array_map_lookup_elem,
779 .map_update_elem = array_map_update_elem,
780 .map_delete_elem = array_map_delete_elem,
781 .map_lookup_percpu_elem = percpu_array_map_lookup_percpu_elem,
782 .map_seq_show_elem = percpu_array_map_seq_show_elem,
783 .map_check_btf = array_map_check_btf,
784 .map_lookup_batch = generic_map_lookup_batch,
785 .map_update_batch = generic_map_update_batch,
786 .map_set_for_each_callback_args = map_set_for_each_callback_args,
787 .map_for_each_callback = bpf_for_each_array_elem,
788 .map_mem_usage = array_map_mem_usage,
789 .map_btf_id = &array_map_btf_ids[0],
790 .iter_seq_info = &iter_seq_info,
791};
792
793static int fd_array_map_alloc_check(union bpf_attr *attr)
794{
795 /* only file descriptors can be stored in this type of map */
796 if (attr->value_size != sizeof(u32))
797 return -EINVAL;
798 /* Program read-only/write-only not supported for special maps yet. */
799 if (attr->map_flags & (BPF_F_RDONLY_PROG | BPF_F_WRONLY_PROG))
800 return -EINVAL;
801 return array_map_alloc_check(attr);
802}
803
804static void fd_array_map_free(struct bpf_map *map)
805{
806 struct bpf_array *array = container_of(map, struct bpf_array, map);
807 int i;
808
809 /* make sure it's empty */
810 for (i = 0; i < array->map.max_entries; i++)
811 BUG_ON(array->ptrs[i] != NULL);
812
813 bpf_map_area_free(base: array);
814}
815
816static void *fd_array_map_lookup_elem(struct bpf_map *map, void *key)
817{
818 return ERR_PTR(error: -EOPNOTSUPP);
819}
820
821/* only called from syscall */
822int bpf_fd_array_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
823{
824 void **elem, *ptr;
825 int ret = 0;
826
827 if (!map->ops->map_fd_sys_lookup_elem)
828 return -ENOTSUPP;
829
830 rcu_read_lock();
831 elem = array_map_lookup_elem(map, key);
832 if (elem && (ptr = READ_ONCE(*elem)))
833 *value = map->ops->map_fd_sys_lookup_elem(ptr);
834 else
835 ret = -ENOENT;
836 rcu_read_unlock();
837
838 return ret;
839}
840
841/* only called from syscall */
842int bpf_fd_array_map_update_elem(struct bpf_map *map, struct file *map_file,
843 void *key, void *value, u64 map_flags)
844{
845 struct bpf_array *array = container_of(map, struct bpf_array, map);
846 void *new_ptr, *old_ptr;
847 u32 index = *(u32 *)key, ufd;
848
849 if (map_flags != BPF_ANY)
850 return -EINVAL;
851
852 if (index >= array->map.max_entries)
853 return -E2BIG;
854
855 ufd = *(u32 *)value;
856 new_ptr = map->ops->map_fd_get_ptr(map, map_file, ufd);
857 if (IS_ERR(ptr: new_ptr))
858 return PTR_ERR(ptr: new_ptr);
859
860 if (map->ops->map_poke_run) {
861 mutex_lock(&array->aux->poke_mutex);
862 old_ptr = xchg(array->ptrs + index, new_ptr);
863 map->ops->map_poke_run(map, index, old_ptr, new_ptr);
864 mutex_unlock(lock: &array->aux->poke_mutex);
865 } else {
866 old_ptr = xchg(array->ptrs + index, new_ptr);
867 }
868
869 if (old_ptr)
870 map->ops->map_fd_put_ptr(old_ptr);
871 return 0;
872}
873
874static long fd_array_map_delete_elem(struct bpf_map *map, void *key)
875{
876 struct bpf_array *array = container_of(map, struct bpf_array, map);
877 void *old_ptr;
878 u32 index = *(u32 *)key;
879
880 if (index >= array->map.max_entries)
881 return -E2BIG;
882
883 if (map->ops->map_poke_run) {
884 mutex_lock(&array->aux->poke_mutex);
885 old_ptr = xchg(array->ptrs + index, NULL);
886 map->ops->map_poke_run(map, index, old_ptr, NULL);
887 mutex_unlock(lock: &array->aux->poke_mutex);
888 } else {
889 old_ptr = xchg(array->ptrs + index, NULL);
890 }
891
892 if (old_ptr) {
893 map->ops->map_fd_put_ptr(old_ptr);
894 return 0;
895 } else {
896 return -ENOENT;
897 }
898}
899
900static void *prog_fd_array_get_ptr(struct bpf_map *map,
901 struct file *map_file, int fd)
902{
903 struct bpf_prog *prog = bpf_prog_get(ufd: fd);
904
905 if (IS_ERR(ptr: prog))
906 return prog;
907
908 if (!bpf_prog_map_compatible(map, fp: prog)) {
909 bpf_prog_put(prog);
910 return ERR_PTR(error: -EINVAL);
911 }
912
913 return prog;
914}
915
916static void prog_fd_array_put_ptr(void *ptr)
917{
918 bpf_prog_put(prog: ptr);
919}
920
921static u32 prog_fd_array_sys_lookup_elem(void *ptr)
922{
923 return ((struct bpf_prog *)ptr)->aux->id;
924}
925
926/* decrement refcnt of all bpf_progs that are stored in this map */
927static void bpf_fd_array_map_clear(struct bpf_map *map)
928{
929 struct bpf_array *array = container_of(map, struct bpf_array, map);
930 int i;
931
932 for (i = 0; i < array->map.max_entries; i++)
933 fd_array_map_delete_elem(map, key: &i);
934}
935
936static void prog_array_map_seq_show_elem(struct bpf_map *map, void *key,
937 struct seq_file *m)
938{
939 void **elem, *ptr;
940 u32 prog_id;
941
942 rcu_read_lock();
943
944 elem = array_map_lookup_elem(map, key);
945 if (elem) {
946 ptr = READ_ONCE(*elem);
947 if (ptr) {
948 seq_printf(m, fmt: "%u: ", *(u32 *)key);
949 prog_id = prog_fd_array_sys_lookup_elem(ptr);
950 btf_type_seq_show(btf: map->btf, type_id: map->btf_value_type_id,
951 obj: &prog_id, m);
952 seq_puts(m, s: "\n");
953 }
954 }
955
956 rcu_read_unlock();
957}
958
959struct prog_poke_elem {
960 struct list_head list;
961 struct bpf_prog_aux *aux;
962};
963
964static int prog_array_map_poke_track(struct bpf_map *map,
965 struct bpf_prog_aux *prog_aux)
966{
967 struct prog_poke_elem *elem;
968 struct bpf_array_aux *aux;
969 int ret = 0;
970
971 aux = container_of(map, struct bpf_array, map)->aux;
972 mutex_lock(&aux->poke_mutex);
973 list_for_each_entry(elem, &aux->poke_progs, list) {
974 if (elem->aux == prog_aux)
975 goto out;
976 }
977
978 elem = kmalloc(size: sizeof(*elem), GFP_KERNEL);
979 if (!elem) {
980 ret = -ENOMEM;
981 goto out;
982 }
983
984 INIT_LIST_HEAD(list: &elem->list);
985 /* We must track the program's aux info at this point in time
986 * since the program pointer itself may not be stable yet, see
987 * also comment in prog_array_map_poke_run().
988 */
989 elem->aux = prog_aux;
990
991 list_add_tail(new: &elem->list, head: &aux->poke_progs);
992out:
993 mutex_unlock(lock: &aux->poke_mutex);
994 return ret;
995}
996
997static void prog_array_map_poke_untrack(struct bpf_map *map,
998 struct bpf_prog_aux *prog_aux)
999{
1000 struct prog_poke_elem *elem, *tmp;
1001 struct bpf_array_aux *aux;
1002
1003 aux = container_of(map, struct bpf_array, map)->aux;
1004 mutex_lock(&aux->poke_mutex);
1005 list_for_each_entry_safe(elem, tmp, &aux->poke_progs, list) {
1006 if (elem->aux == prog_aux) {
1007 list_del_init(entry: &elem->list);
1008 kfree(objp: elem);
1009 break;
1010 }
1011 }
1012 mutex_unlock(lock: &aux->poke_mutex);
1013}
1014
1015static void prog_array_map_poke_run(struct bpf_map *map, u32 key,
1016 struct bpf_prog *old,
1017 struct bpf_prog *new)
1018{
1019 u8 *old_addr, *new_addr, *old_bypass_addr;
1020 struct prog_poke_elem *elem;
1021 struct bpf_array_aux *aux;
1022
1023 aux = container_of(map, struct bpf_array, map)->aux;
1024 WARN_ON_ONCE(!mutex_is_locked(&aux->poke_mutex));
1025
1026 list_for_each_entry(elem, &aux->poke_progs, list) {
1027 struct bpf_jit_poke_descriptor *poke;
1028 int i, ret;
1029
1030 for (i = 0; i < elem->aux->size_poke_tab; i++) {
1031 poke = &elem->aux->poke_tab[i];
1032
1033 /* Few things to be aware of:
1034 *
1035 * 1) We can only ever access aux in this context, but
1036 * not aux->prog since it might not be stable yet and
1037 * there could be danger of use after free otherwise.
1038 * 2) Initially when we start tracking aux, the program
1039 * is not JITed yet and also does not have a kallsyms
1040 * entry. We skip these as poke->tailcall_target_stable
1041 * is not active yet. The JIT will do the final fixup
1042 * before setting it stable. The various
1043 * poke->tailcall_target_stable are successively
1044 * activated, so tail call updates can arrive from here
1045 * while JIT is still finishing its final fixup for
1046 * non-activated poke entries.
1047 * 3) On program teardown, the program's kallsym entry gets
1048 * removed out of RCU callback, but we can only untrack
1049 * from sleepable context, therefore bpf_arch_text_poke()
1050 * might not see that this is in BPF text section and
1051 * bails out with -EINVAL. As these are unreachable since
1052 * RCU grace period already passed, we simply skip them.
1053 * 4) Also programs reaching refcount of zero while patching
1054 * is in progress is okay since we're protected under
1055 * poke_mutex and untrack the programs before the JIT
1056 * buffer is freed. When we're still in the middle of
1057 * patching and suddenly kallsyms entry of the program
1058 * gets evicted, we just skip the rest which is fine due
1059 * to point 3).
1060 * 5) Any other error happening below from bpf_arch_text_poke()
1061 * is a unexpected bug.
1062 */
1063 if (!READ_ONCE(poke->tailcall_target_stable))
1064 continue;
1065 if (poke->reason != BPF_POKE_REASON_TAIL_CALL)
1066 continue;
1067 if (poke->tail_call.map != map ||
1068 poke->tail_call.key != key)
1069 continue;
1070
1071 old_bypass_addr = old ? NULL : poke->bypass_addr;
1072 old_addr = old ? (u8 *)old->bpf_func + poke->adj_off : NULL;
1073 new_addr = new ? (u8 *)new->bpf_func + poke->adj_off : NULL;
1074
1075 if (new) {
1076 ret = bpf_arch_text_poke(ip: poke->tailcall_target,
1077 t: BPF_MOD_JUMP,
1078 addr1: old_addr, addr2: new_addr);
1079 BUG_ON(ret < 0 && ret != -EINVAL);
1080 if (!old) {
1081 ret = bpf_arch_text_poke(ip: poke->tailcall_bypass,
1082 t: BPF_MOD_JUMP,
1083 addr1: poke->bypass_addr,
1084 NULL);
1085 BUG_ON(ret < 0 && ret != -EINVAL);
1086 }
1087 } else {
1088 ret = bpf_arch_text_poke(ip: poke->tailcall_bypass,
1089 t: BPF_MOD_JUMP,
1090 addr1: old_bypass_addr,
1091 addr2: poke->bypass_addr);
1092 BUG_ON(ret < 0 && ret != -EINVAL);
1093 /* let other CPUs finish the execution of program
1094 * so that it will not possible to expose them
1095 * to invalid nop, stack unwind, nop state
1096 */
1097 if (!ret)
1098 synchronize_rcu();
1099 ret = bpf_arch_text_poke(ip: poke->tailcall_target,
1100 t: BPF_MOD_JUMP,
1101 addr1: old_addr, NULL);
1102 BUG_ON(ret < 0 && ret != -EINVAL);
1103 }
1104 }
1105 }
1106}
1107
1108static void prog_array_map_clear_deferred(struct work_struct *work)
1109{
1110 struct bpf_map *map = container_of(work, struct bpf_array_aux,
1111 work)->map;
1112 bpf_fd_array_map_clear(map);
1113 bpf_map_put(map);
1114}
1115
1116static void prog_array_map_clear(struct bpf_map *map)
1117{
1118 struct bpf_array_aux *aux = container_of(map, struct bpf_array,
1119 map)->aux;
1120 bpf_map_inc(map);
1121 schedule_work(work: &aux->work);
1122}
1123
1124static struct bpf_map *prog_array_map_alloc(union bpf_attr *attr)
1125{
1126 struct bpf_array_aux *aux;
1127 struct bpf_map *map;
1128
1129 aux = kzalloc(size: sizeof(*aux), GFP_KERNEL_ACCOUNT);
1130 if (!aux)
1131 return ERR_PTR(error: -ENOMEM);
1132
1133 INIT_WORK(&aux->work, prog_array_map_clear_deferred);
1134 INIT_LIST_HEAD(list: &aux->poke_progs);
1135 mutex_init(&aux->poke_mutex);
1136
1137 map = array_map_alloc(attr);
1138 if (IS_ERR(ptr: map)) {
1139 kfree(objp: aux);
1140 return map;
1141 }
1142
1143 container_of(map, struct bpf_array, map)->aux = aux;
1144 aux->map = map;
1145
1146 return map;
1147}
1148
1149static void prog_array_map_free(struct bpf_map *map)
1150{
1151 struct prog_poke_elem *elem, *tmp;
1152 struct bpf_array_aux *aux;
1153
1154 aux = container_of(map, struct bpf_array, map)->aux;
1155 list_for_each_entry_safe(elem, tmp, &aux->poke_progs, list) {
1156 list_del_init(entry: &elem->list);
1157 kfree(objp: elem);
1158 }
1159 kfree(objp: aux);
1160 fd_array_map_free(map);
1161}
1162
1163/* prog_array->aux->{type,jited} is a runtime binding.
1164 * Doing static check alone in the verifier is not enough.
1165 * Thus, prog_array_map cannot be used as an inner_map
1166 * and map_meta_equal is not implemented.
1167 */
1168const struct bpf_map_ops prog_array_map_ops = {
1169 .map_alloc_check = fd_array_map_alloc_check,
1170 .map_alloc = prog_array_map_alloc,
1171 .map_free = prog_array_map_free,
1172 .map_poke_track = prog_array_map_poke_track,
1173 .map_poke_untrack = prog_array_map_poke_untrack,
1174 .map_poke_run = prog_array_map_poke_run,
1175 .map_get_next_key = array_map_get_next_key,
1176 .map_lookup_elem = fd_array_map_lookup_elem,
1177 .map_delete_elem = fd_array_map_delete_elem,
1178 .map_fd_get_ptr = prog_fd_array_get_ptr,
1179 .map_fd_put_ptr = prog_fd_array_put_ptr,
1180 .map_fd_sys_lookup_elem = prog_fd_array_sys_lookup_elem,
1181 .map_release_uref = prog_array_map_clear,
1182 .map_seq_show_elem = prog_array_map_seq_show_elem,
1183 .map_mem_usage = array_map_mem_usage,
1184 .map_btf_id = &array_map_btf_ids[0],
1185};
1186
1187static struct bpf_event_entry *bpf_event_entry_gen(struct file *perf_file,
1188 struct file *map_file)
1189{
1190 struct bpf_event_entry *ee;
1191
1192 ee = kzalloc(size: sizeof(*ee), GFP_ATOMIC);
1193 if (ee) {
1194 ee->event = perf_file->private_data;
1195 ee->perf_file = perf_file;
1196 ee->map_file = map_file;
1197 }
1198
1199 return ee;
1200}
1201
1202static void __bpf_event_entry_free(struct rcu_head *rcu)
1203{
1204 struct bpf_event_entry *ee;
1205
1206 ee = container_of(rcu, struct bpf_event_entry, rcu);
1207 fput(ee->perf_file);
1208 kfree(objp: ee);
1209}
1210
1211static void bpf_event_entry_free_rcu(struct bpf_event_entry *ee)
1212{
1213 call_rcu(head: &ee->rcu, func: __bpf_event_entry_free);
1214}
1215
1216static void *perf_event_fd_array_get_ptr(struct bpf_map *map,
1217 struct file *map_file, int fd)
1218{
1219 struct bpf_event_entry *ee;
1220 struct perf_event *event;
1221 struct file *perf_file;
1222 u64 value;
1223
1224 perf_file = perf_event_get(fd);
1225 if (IS_ERR(ptr: perf_file))
1226 return perf_file;
1227
1228 ee = ERR_PTR(error: -EOPNOTSUPP);
1229 event = perf_file->private_data;
1230 if (perf_event_read_local(event, value: &value, NULL, NULL) == -EOPNOTSUPP)
1231 goto err_out;
1232
1233 ee = bpf_event_entry_gen(perf_file, map_file);
1234 if (ee)
1235 return ee;
1236 ee = ERR_PTR(error: -ENOMEM);
1237err_out:
1238 fput(perf_file);
1239 return ee;
1240}
1241
1242static void perf_event_fd_array_put_ptr(void *ptr)
1243{
1244 bpf_event_entry_free_rcu(ee: ptr);
1245}
1246
1247static void perf_event_fd_array_release(struct bpf_map *map,
1248 struct file *map_file)
1249{
1250 struct bpf_array *array = container_of(map, struct bpf_array, map);
1251 struct bpf_event_entry *ee;
1252 int i;
1253
1254 if (map->map_flags & BPF_F_PRESERVE_ELEMS)
1255 return;
1256
1257 rcu_read_lock();
1258 for (i = 0; i < array->map.max_entries; i++) {
1259 ee = READ_ONCE(array->ptrs[i]);
1260 if (ee && ee->map_file == map_file)
1261 fd_array_map_delete_elem(map, key: &i);
1262 }
1263 rcu_read_unlock();
1264}
1265
1266static void perf_event_fd_array_map_free(struct bpf_map *map)
1267{
1268 if (map->map_flags & BPF_F_PRESERVE_ELEMS)
1269 bpf_fd_array_map_clear(map);
1270 fd_array_map_free(map);
1271}
1272
1273const struct bpf_map_ops perf_event_array_map_ops = {
1274 .map_meta_equal = bpf_map_meta_equal,
1275 .map_alloc_check = fd_array_map_alloc_check,
1276 .map_alloc = array_map_alloc,
1277 .map_free = perf_event_fd_array_map_free,
1278 .map_get_next_key = array_map_get_next_key,
1279 .map_lookup_elem = fd_array_map_lookup_elem,
1280 .map_delete_elem = fd_array_map_delete_elem,
1281 .map_fd_get_ptr = perf_event_fd_array_get_ptr,
1282 .map_fd_put_ptr = perf_event_fd_array_put_ptr,
1283 .map_release = perf_event_fd_array_release,
1284 .map_check_btf = map_check_no_btf,
1285 .map_mem_usage = array_map_mem_usage,
1286 .map_btf_id = &array_map_btf_ids[0],
1287};
1288
1289#ifdef CONFIG_CGROUPS
1290static void *cgroup_fd_array_get_ptr(struct bpf_map *map,
1291 struct file *map_file /* not used */,
1292 int fd)
1293{
1294 return cgroup_get_from_fd(fd);
1295}
1296
1297static void cgroup_fd_array_put_ptr(void *ptr)
1298{
1299 /* cgroup_put free cgrp after a rcu grace period */
1300 cgroup_put(cgrp: ptr);
1301}
1302
1303static void cgroup_fd_array_free(struct bpf_map *map)
1304{
1305 bpf_fd_array_map_clear(map);
1306 fd_array_map_free(map);
1307}
1308
1309const struct bpf_map_ops cgroup_array_map_ops = {
1310 .map_meta_equal = bpf_map_meta_equal,
1311 .map_alloc_check = fd_array_map_alloc_check,
1312 .map_alloc = array_map_alloc,
1313 .map_free = cgroup_fd_array_free,
1314 .map_get_next_key = array_map_get_next_key,
1315 .map_lookup_elem = fd_array_map_lookup_elem,
1316 .map_delete_elem = fd_array_map_delete_elem,
1317 .map_fd_get_ptr = cgroup_fd_array_get_ptr,
1318 .map_fd_put_ptr = cgroup_fd_array_put_ptr,
1319 .map_check_btf = map_check_no_btf,
1320 .map_mem_usage = array_map_mem_usage,
1321 .map_btf_id = &array_map_btf_ids[0],
1322};
1323#endif
1324
1325static struct bpf_map *array_of_map_alloc(union bpf_attr *attr)
1326{
1327 struct bpf_map *map, *inner_map_meta;
1328
1329 inner_map_meta = bpf_map_meta_alloc(inner_map_ufd: attr->inner_map_fd);
1330 if (IS_ERR(ptr: inner_map_meta))
1331 return inner_map_meta;
1332
1333 map = array_map_alloc(attr);
1334 if (IS_ERR(ptr: map)) {
1335 bpf_map_meta_free(map_meta: inner_map_meta);
1336 return map;
1337 }
1338
1339 map->inner_map_meta = inner_map_meta;
1340
1341 return map;
1342}
1343
1344static void array_of_map_free(struct bpf_map *map)
1345{
1346 /* map->inner_map_meta is only accessed by syscall which
1347 * is protected by fdget/fdput.
1348 */
1349 bpf_map_meta_free(map_meta: map->inner_map_meta);
1350 bpf_fd_array_map_clear(map);
1351 fd_array_map_free(map);
1352}
1353
1354static void *array_of_map_lookup_elem(struct bpf_map *map, void *key)
1355{
1356 struct bpf_map **inner_map = array_map_lookup_elem(map, key);
1357
1358 if (!inner_map)
1359 return NULL;
1360
1361 return READ_ONCE(*inner_map);
1362}
1363
1364static int array_of_map_gen_lookup(struct bpf_map *map,
1365 struct bpf_insn *insn_buf)
1366{
1367 struct bpf_array *array = container_of(map, struct bpf_array, map);
1368 u32 elem_size = array->elem_size;
1369 struct bpf_insn *insn = insn_buf;
1370 const int ret = BPF_REG_0;
1371 const int map_ptr = BPF_REG_1;
1372 const int index = BPF_REG_2;
1373
1374 *insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
1375 *insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
1376 if (!map->bypass_spec_v1) {
1377 *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 6);
1378 *insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
1379 } else {
1380 *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 5);
1381 }
1382 if (is_power_of_2(n: elem_size))
1383 *insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(elem_size));
1384 else
1385 *insn++ = BPF_ALU64_IMM(BPF_MUL, ret, elem_size);
1386 *insn++ = BPF_ALU64_REG(BPF_ADD, ret, map_ptr);
1387 *insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0);
1388 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1);
1389 *insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
1390 *insn++ = BPF_MOV64_IMM(ret, 0);
1391
1392 return insn - insn_buf;
1393}
1394
1395const struct bpf_map_ops array_of_maps_map_ops = {
1396 .map_alloc_check = fd_array_map_alloc_check,
1397 .map_alloc = array_of_map_alloc,
1398 .map_free = array_of_map_free,
1399 .map_get_next_key = array_map_get_next_key,
1400 .map_lookup_elem = array_of_map_lookup_elem,
1401 .map_delete_elem = fd_array_map_delete_elem,
1402 .map_fd_get_ptr = bpf_map_fd_get_ptr,
1403 .map_fd_put_ptr = bpf_map_fd_put_ptr,
1404 .map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
1405 .map_gen_lookup = array_of_map_gen_lookup,
1406 .map_lookup_batch = generic_map_lookup_batch,
1407 .map_update_batch = generic_map_update_batch,
1408 .map_check_btf = map_check_no_btf,
1409 .map_mem_usage = array_map_mem_usage,
1410 .map_btf_id = &array_map_btf_ids[0],
1411};
1412

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