1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
3 * Copyright (c) 2016,2017 Facebook
8 #include <linux/slab.h>
10 #include <linux/filter.h>
11 #include <linux/perf_event.h>
12 #include <uapi/linux/btf.h>
13 #include <linux/rcupdate_trace.h>
15 #include "map_in_map.h"
17 #define ARRAY_CREATE_FLAG_MASK \
18 (BPF_F_NUMA_NODE | BPF_F_MMAPABLE | BPF_F_ACCESS_MASK | \
19 BPF_F_PRESERVE_ELEMS | BPF_F_INNER_MAP)
21 static void bpf_array_free_percpu(struct bpf_array *array)
25 for (i = 0; i < array->map.max_entries; i++) {
26 free_percpu(array->pptrs[i]);
31 static int bpf_array_alloc_percpu(struct bpf_array *array)
36 for (i = 0; i < array->map.max_entries; i++) {
37 ptr = __alloc_percpu_gfp(array->elem_size, 8,
38 GFP_USER | __GFP_NOWARN);
40 bpf_array_free_percpu(array);
43 array->pptrs[i] = ptr;
50 /* Called from syscall */
51 int array_map_alloc_check(union bpf_attr *attr)
53 bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
54 int numa_node = bpf_map_attr_numa_node(attr);
56 /* check sanity of attributes */
57 if (attr->max_entries == 0 || attr->key_size != 4 ||
58 attr->value_size == 0 ||
59 attr->map_flags & ~ARRAY_CREATE_FLAG_MASK ||
60 !bpf_map_flags_access_ok(attr->map_flags) ||
61 (percpu && numa_node != NUMA_NO_NODE))
64 if (attr->map_type != BPF_MAP_TYPE_ARRAY &&
65 attr->map_flags & (BPF_F_MMAPABLE | BPF_F_INNER_MAP))
68 if (attr->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY &&
69 attr->map_flags & BPF_F_PRESERVE_ELEMS)
72 if (attr->value_size > KMALLOC_MAX_SIZE)
73 /* if value_size is bigger, the user space won't be able to
74 * access the elements.
81 static struct bpf_map *array_map_alloc(union bpf_attr *attr)
83 bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
84 int ret, numa_node = bpf_map_attr_numa_node(attr);
85 u32 elem_size, index_mask, max_entries;
86 bool bypass_spec_v1 = bpf_bypass_spec_v1();
87 u64 cost, array_size, mask64;
88 struct bpf_map_memory mem;
89 struct bpf_array *array;
91 elem_size = round_up(attr->value_size, 8);
93 max_entries = attr->max_entries;
95 /* On 32 bit archs roundup_pow_of_two() with max_entries that has
96 * upper most bit set in u32 space is undefined behavior due to
97 * resulting 1U << 32, so do it manually here in u64 space.
99 mask64 = fls_long(max_entries - 1);
100 mask64 = 1ULL << mask64;
104 if (!bypass_spec_v1) {
105 /* round up array size to nearest power of 2,
106 * since cpu will speculate within index_mask limits
108 max_entries = index_mask + 1;
109 /* Check for overflows. */
110 if (max_entries < attr->max_entries)
111 return ERR_PTR(-E2BIG);
114 array_size = sizeof(*array);
116 array_size += (u64) max_entries * sizeof(void *);
118 /* rely on vmalloc() to return page-aligned memory and
119 * ensure array->value is exactly page-aligned
121 if (attr->map_flags & BPF_F_MMAPABLE) {
122 array_size = PAGE_ALIGN(array_size);
123 array_size += PAGE_ALIGN((u64) max_entries * elem_size);
125 array_size += (u64) max_entries * elem_size;
129 /* make sure there is no u32 overflow later in round_up() */
132 cost += (u64)attr->max_entries * elem_size * num_possible_cpus();
134 ret = bpf_map_charge_init(&mem, cost);
138 /* allocate all map elements and zero-initialize them */
139 if (attr->map_flags & BPF_F_MMAPABLE) {
142 /* kmalloc'ed memory can't be mmap'ed, use explicit vmalloc */
143 data = bpf_map_area_mmapable_alloc(array_size, numa_node);
145 bpf_map_charge_finish(&mem);
146 return ERR_PTR(-ENOMEM);
148 array = data + PAGE_ALIGN(sizeof(struct bpf_array))
149 - offsetof(struct bpf_array, value);
151 array = bpf_map_area_alloc(array_size, numa_node);
154 bpf_map_charge_finish(&mem);
155 return ERR_PTR(-ENOMEM);
157 array->index_mask = index_mask;
158 array->map.bypass_spec_v1 = bypass_spec_v1;
160 /* copy mandatory map attributes */
161 bpf_map_init_from_attr(&array->map, attr);
162 bpf_map_charge_move(&array->map.memory, &mem);
163 array->elem_size = elem_size;
165 if (percpu && bpf_array_alloc_percpu(array)) {
166 bpf_map_charge_finish(&array->map.memory);
167 bpf_map_area_free(array);
168 return ERR_PTR(-ENOMEM);
174 /* Called from syscall or from eBPF program */
175 static void *array_map_lookup_elem(struct bpf_map *map, void *key)
177 struct bpf_array *array = container_of(map, struct bpf_array, map);
178 u32 index = *(u32 *)key;
180 if (unlikely(index >= array->map.max_entries))
183 return array->value + array->elem_size * (index & array->index_mask);
186 static int array_map_direct_value_addr(const struct bpf_map *map, u64 *imm,
189 struct bpf_array *array = container_of(map, struct bpf_array, map);
191 if (map->max_entries != 1)
193 if (off >= map->value_size)
196 *imm = (unsigned long)array->value;
200 static int array_map_direct_value_meta(const struct bpf_map *map, u64 imm,
203 struct bpf_array *array = container_of(map, struct bpf_array, map);
204 u64 base = (unsigned long)array->value;
205 u64 range = array->elem_size;
207 if (map->max_entries != 1)
209 if (imm < base || imm >= base + range)
216 /* emit BPF instructions equivalent to C code of array_map_lookup_elem() */
217 static int array_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
219 struct bpf_array *array = container_of(map, struct bpf_array, map);
220 struct bpf_insn *insn = insn_buf;
221 u32 elem_size = round_up(map->value_size, 8);
222 const int ret = BPF_REG_0;
223 const int map_ptr = BPF_REG_1;
224 const int index = BPF_REG_2;
226 if (map->map_flags & BPF_F_INNER_MAP)
229 *insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
230 *insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
231 if (!map->bypass_spec_v1) {
232 *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 4);
233 *insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
235 *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 3);
238 if (is_power_of_2(elem_size)) {
239 *insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(elem_size));
241 *insn++ = BPF_ALU64_IMM(BPF_MUL, ret, elem_size);
243 *insn++ = BPF_ALU64_REG(BPF_ADD, ret, map_ptr);
244 *insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
245 *insn++ = BPF_MOV64_IMM(ret, 0);
246 return insn - insn_buf;
249 /* Called from eBPF program */
250 static void *percpu_array_map_lookup_elem(struct bpf_map *map, void *key)
252 struct bpf_array *array = container_of(map, struct bpf_array, map);
253 u32 index = *(u32 *)key;
255 if (unlikely(index >= array->map.max_entries))
258 return this_cpu_ptr(array->pptrs[index & array->index_mask]);
261 int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value)
263 struct bpf_array *array = container_of(map, struct bpf_array, map);
264 u32 index = *(u32 *)key;
269 if (unlikely(index >= array->map.max_entries))
272 /* per_cpu areas are zero-filled and bpf programs can only
273 * access 'value_size' of them, so copying rounded areas
274 * will not leak any kernel data
276 size = round_up(map->value_size, 8);
278 pptr = array->pptrs[index & array->index_mask];
279 for_each_possible_cpu(cpu) {
280 bpf_long_memcpy(value + off, per_cpu_ptr(pptr, cpu), size);
287 /* Called from syscall */
288 static int array_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
290 struct bpf_array *array = container_of(map, struct bpf_array, map);
291 u32 index = key ? *(u32 *)key : U32_MAX;
292 u32 *next = (u32 *)next_key;
294 if (index >= array->map.max_entries) {
299 if (index == array->map.max_entries - 1)
306 /* Called from syscall or from eBPF program */
307 static int array_map_update_elem(struct bpf_map *map, void *key, void *value,
310 struct bpf_array *array = container_of(map, struct bpf_array, map);
311 u32 index = *(u32 *)key;
314 if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST))
318 if (unlikely(index >= array->map.max_entries))
319 /* all elements were pre-allocated, cannot insert a new one */
322 if (unlikely(map_flags & BPF_NOEXIST))
323 /* all elements already exist */
326 if (unlikely((map_flags & BPF_F_LOCK) &&
327 !map_value_has_spin_lock(map)))
330 if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
331 memcpy(this_cpu_ptr(array->pptrs[index & array->index_mask]),
332 value, map->value_size);
335 array->elem_size * (index & array->index_mask);
336 if (map_flags & BPF_F_LOCK)
337 copy_map_value_locked(map, val, value, false);
339 copy_map_value(map, val, value);
344 int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
347 struct bpf_array *array = container_of(map, struct bpf_array, map);
348 u32 index = *(u32 *)key;
353 if (unlikely(map_flags > BPF_EXIST))
357 if (unlikely(index >= array->map.max_entries))
358 /* all elements were pre-allocated, cannot insert a new one */
361 if (unlikely(map_flags == BPF_NOEXIST))
362 /* all elements already exist */
365 /* the user space will provide round_up(value_size, 8) bytes that
366 * will be copied into per-cpu area. bpf programs can only access
367 * value_size of it. During lookup the same extra bytes will be
368 * returned or zeros which were zero-filled by percpu_alloc,
369 * so no kernel data leaks possible
371 size = round_up(map->value_size, 8);
373 pptr = array->pptrs[index & array->index_mask];
374 for_each_possible_cpu(cpu) {
375 bpf_long_memcpy(per_cpu_ptr(pptr, cpu), value + off, size);
382 /* Called from syscall or from eBPF program */
383 static int array_map_delete_elem(struct bpf_map *map, void *key)
388 static void *array_map_vmalloc_addr(struct bpf_array *array)
390 return (void *)round_down((unsigned long)array, PAGE_SIZE);
393 /* Called when map->refcnt goes to zero, either from workqueue or from syscall */
394 static void array_map_free(struct bpf_map *map)
396 struct bpf_array *array = container_of(map, struct bpf_array, map);
398 if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
399 bpf_array_free_percpu(array);
401 if (array->map.map_flags & BPF_F_MMAPABLE)
402 bpf_map_area_free(array_map_vmalloc_addr(array));
404 bpf_map_area_free(array);
407 static void array_map_seq_show_elem(struct bpf_map *map, void *key,
414 value = array_map_lookup_elem(map, key);
420 if (map->btf_key_type_id)
421 seq_printf(m, "%u: ", *(u32 *)key);
422 btf_type_seq_show(map->btf, map->btf_value_type_id, value, m);
428 static void percpu_array_map_seq_show_elem(struct bpf_map *map, void *key,
431 struct bpf_array *array = container_of(map, struct bpf_array, map);
432 u32 index = *(u32 *)key;
438 seq_printf(m, "%u: {\n", *(u32 *)key);
439 pptr = array->pptrs[index & array->index_mask];
440 for_each_possible_cpu(cpu) {
441 seq_printf(m, "\tcpu%d: ", cpu);
442 btf_type_seq_show(map->btf, map->btf_value_type_id,
443 per_cpu_ptr(pptr, cpu), m);
451 static int array_map_check_btf(const struct bpf_map *map,
452 const struct btf *btf,
453 const struct btf_type *key_type,
454 const struct btf_type *value_type)
458 /* One exception for keyless BTF: .bss/.data/.rodata map */
459 if (btf_type_is_void(key_type)) {
460 if (map->map_type != BPF_MAP_TYPE_ARRAY ||
461 map->max_entries != 1)
464 if (BTF_INFO_KIND(value_type->info) != BTF_KIND_DATASEC)
470 if (BTF_INFO_KIND(key_type->info) != BTF_KIND_INT)
473 int_data = *(u32 *)(key_type + 1);
474 /* bpf array can only take a u32 key. This check makes sure
475 * that the btf matches the attr used during map_create.
477 if (BTF_INT_BITS(int_data) != 32 || BTF_INT_OFFSET(int_data))
483 static int array_map_mmap(struct bpf_map *map, struct vm_area_struct *vma)
485 struct bpf_array *array = container_of(map, struct bpf_array, map);
486 pgoff_t pgoff = PAGE_ALIGN(sizeof(*array)) >> PAGE_SHIFT;
488 if (!(map->map_flags & BPF_F_MMAPABLE))
491 if (vma->vm_pgoff * PAGE_SIZE + (vma->vm_end - vma->vm_start) >
492 PAGE_ALIGN((u64)array->map.max_entries * array->elem_size))
495 return remap_vmalloc_range(vma, array_map_vmalloc_addr(array),
496 vma->vm_pgoff + pgoff);
499 static bool array_map_meta_equal(const struct bpf_map *meta0,
500 const struct bpf_map *meta1)
502 if (!bpf_map_meta_equal(meta0, meta1))
504 return meta0->map_flags & BPF_F_INNER_MAP ? true :
505 meta0->max_entries == meta1->max_entries;
508 struct bpf_iter_seq_array_map_info {
510 void *percpu_value_buf;
514 static void *bpf_array_map_seq_start(struct seq_file *seq, loff_t *pos)
516 struct bpf_iter_seq_array_map_info *info = seq->private;
517 struct bpf_map *map = info->map;
518 struct bpf_array *array;
521 if (info->index >= map->max_entries)
526 array = container_of(map, struct bpf_array, map);
527 index = info->index & array->index_mask;
528 if (info->percpu_value_buf)
529 return array->pptrs[index];
530 return array->value + array->elem_size * index;
533 static void *bpf_array_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
535 struct bpf_iter_seq_array_map_info *info = seq->private;
536 struct bpf_map *map = info->map;
537 struct bpf_array *array;
542 if (info->index >= map->max_entries)
545 array = container_of(map, struct bpf_array, map);
546 index = info->index & array->index_mask;
547 if (info->percpu_value_buf)
548 return array->pptrs[index];
549 return array->value + array->elem_size * index;
552 static int __bpf_array_map_seq_show(struct seq_file *seq, void *v)
554 struct bpf_iter_seq_array_map_info *info = seq->private;
555 struct bpf_iter__bpf_map_elem ctx = {};
556 struct bpf_map *map = info->map;
557 struct bpf_iter_meta meta;
558 struct bpf_prog *prog;
559 int off = 0, cpu = 0;
560 void __percpu **pptr;
564 prog = bpf_iter_get_info(&meta, v == NULL);
571 ctx.key = &info->index;
573 if (!info->percpu_value_buf) {
577 size = round_up(map->value_size, 8);
578 for_each_possible_cpu(cpu) {
579 bpf_long_memcpy(info->percpu_value_buf + off,
580 per_cpu_ptr(pptr, cpu),
584 ctx.value = info->percpu_value_buf;
588 return bpf_iter_run_prog(prog, &ctx);
591 static int bpf_array_map_seq_show(struct seq_file *seq, void *v)
593 return __bpf_array_map_seq_show(seq, v);
596 static void bpf_array_map_seq_stop(struct seq_file *seq, void *v)
599 (void)__bpf_array_map_seq_show(seq, NULL);
602 static int bpf_iter_init_array_map(void *priv_data,
603 struct bpf_iter_aux_info *aux)
605 struct bpf_iter_seq_array_map_info *seq_info = priv_data;
606 struct bpf_map *map = aux->map;
610 if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
611 buf_size = round_up(map->value_size, 8) * num_possible_cpus();
612 value_buf = kmalloc(buf_size, GFP_USER | __GFP_NOWARN);
616 seq_info->percpu_value_buf = value_buf;
619 /* bpf_iter_attach_map() acquires a map uref, and the uref may be
620 * released before or in the middle of iterating map elements, so
621 * acquire an extra map uref for iterator.
623 bpf_map_inc_with_uref(map);
628 static void bpf_iter_fini_array_map(void *priv_data)
630 struct bpf_iter_seq_array_map_info *seq_info = priv_data;
632 bpf_map_put_with_uref(seq_info->map);
633 kfree(seq_info->percpu_value_buf);
636 static const struct seq_operations bpf_array_map_seq_ops = {
637 .start = bpf_array_map_seq_start,
638 .next = bpf_array_map_seq_next,
639 .stop = bpf_array_map_seq_stop,
640 .show = bpf_array_map_seq_show,
643 static const struct bpf_iter_seq_info iter_seq_info = {
644 .seq_ops = &bpf_array_map_seq_ops,
645 .init_seq_private = bpf_iter_init_array_map,
646 .fini_seq_private = bpf_iter_fini_array_map,
647 .seq_priv_size = sizeof(struct bpf_iter_seq_array_map_info),
650 static int array_map_btf_id;
651 const struct bpf_map_ops array_map_ops = {
652 .map_meta_equal = array_map_meta_equal,
653 .map_alloc_check = array_map_alloc_check,
654 .map_alloc = array_map_alloc,
655 .map_free = array_map_free,
656 .map_get_next_key = array_map_get_next_key,
657 .map_lookup_elem = array_map_lookup_elem,
658 .map_update_elem = array_map_update_elem,
659 .map_delete_elem = array_map_delete_elem,
660 .map_gen_lookup = array_map_gen_lookup,
661 .map_direct_value_addr = array_map_direct_value_addr,
662 .map_direct_value_meta = array_map_direct_value_meta,
663 .map_mmap = array_map_mmap,
664 .map_seq_show_elem = array_map_seq_show_elem,
665 .map_check_btf = array_map_check_btf,
666 .map_lookup_batch = generic_map_lookup_batch,
667 .map_update_batch = generic_map_update_batch,
668 .map_btf_name = "bpf_array",
669 .map_btf_id = &array_map_btf_id,
670 .iter_seq_info = &iter_seq_info,
673 static int percpu_array_map_btf_id;
674 const struct bpf_map_ops percpu_array_map_ops = {
675 .map_meta_equal = bpf_map_meta_equal,
676 .map_alloc_check = array_map_alloc_check,
677 .map_alloc = array_map_alloc,
678 .map_free = array_map_free,
679 .map_get_next_key = array_map_get_next_key,
680 .map_lookup_elem = percpu_array_map_lookup_elem,
681 .map_update_elem = array_map_update_elem,
682 .map_delete_elem = array_map_delete_elem,
683 .map_seq_show_elem = percpu_array_map_seq_show_elem,
684 .map_check_btf = array_map_check_btf,
685 .map_btf_name = "bpf_array",
686 .map_btf_id = &percpu_array_map_btf_id,
687 .iter_seq_info = &iter_seq_info,
690 static int fd_array_map_alloc_check(union bpf_attr *attr)
692 /* only file descriptors can be stored in this type of map */
693 if (attr->value_size != sizeof(u32))
695 /* Program read-only/write-only not supported for special maps yet. */
696 if (attr->map_flags & (BPF_F_RDONLY_PROG | BPF_F_WRONLY_PROG))
698 return array_map_alloc_check(attr);
701 static void fd_array_map_free(struct bpf_map *map)
703 struct bpf_array *array = container_of(map, struct bpf_array, map);
706 /* make sure it's empty */
707 for (i = 0; i < array->map.max_entries; i++)
708 BUG_ON(array->ptrs[i] != NULL);
710 bpf_map_area_free(array);
713 static void *fd_array_map_lookup_elem(struct bpf_map *map, void *key)
715 return ERR_PTR(-EOPNOTSUPP);
718 /* only called from syscall */
719 int bpf_fd_array_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
724 if (!map->ops->map_fd_sys_lookup_elem)
728 elem = array_map_lookup_elem(map, key);
729 if (elem && (ptr = READ_ONCE(*elem)))
730 *value = map->ops->map_fd_sys_lookup_elem(ptr);
738 /* only called from syscall */
739 int bpf_fd_array_map_update_elem(struct bpf_map *map, struct file *map_file,
740 void *key, void *value, u64 map_flags)
742 struct bpf_array *array = container_of(map, struct bpf_array, map);
743 void *new_ptr, *old_ptr;
744 u32 index = *(u32 *)key, ufd;
746 if (map_flags != BPF_ANY)
749 if (index >= array->map.max_entries)
753 new_ptr = map->ops->map_fd_get_ptr(map, map_file, ufd);
755 return PTR_ERR(new_ptr);
757 if (map->ops->map_poke_run) {
758 mutex_lock(&array->aux->poke_mutex);
759 old_ptr = xchg(array->ptrs + index, new_ptr);
760 map->ops->map_poke_run(map, index, old_ptr, new_ptr);
761 mutex_unlock(&array->aux->poke_mutex);
763 old_ptr = xchg(array->ptrs + index, new_ptr);
767 map->ops->map_fd_put_ptr(map, old_ptr, true);
771 static int fd_array_map_delete_elem(struct bpf_map *map, void *key)
773 struct bpf_array *array = container_of(map, struct bpf_array, map);
775 u32 index = *(u32 *)key;
777 if (index >= array->map.max_entries)
780 if (map->ops->map_poke_run) {
781 mutex_lock(&array->aux->poke_mutex);
782 old_ptr = xchg(array->ptrs + index, NULL);
783 map->ops->map_poke_run(map, index, old_ptr, NULL);
784 mutex_unlock(&array->aux->poke_mutex);
786 old_ptr = xchg(array->ptrs + index, NULL);
790 map->ops->map_fd_put_ptr(map, old_ptr, true);
797 static void *prog_fd_array_get_ptr(struct bpf_map *map,
798 struct file *map_file, int fd)
800 struct bpf_array *array = container_of(map, struct bpf_array, map);
801 struct bpf_prog *prog = bpf_prog_get(fd);
806 if (!bpf_prog_array_compatible(array, prog)) {
808 return ERR_PTR(-EINVAL);
814 static void prog_fd_array_put_ptr(struct bpf_map *map, void *ptr, bool need_defer)
816 /* bpf_prog is freed after one RCU or tasks trace grace period */
820 static u32 prog_fd_array_sys_lookup_elem(void *ptr)
822 return ((struct bpf_prog *)ptr)->aux->id;
825 /* decrement refcnt of all bpf_progs that are stored in this map */
826 static void bpf_fd_array_map_clear(struct bpf_map *map)
828 struct bpf_array *array = container_of(map, struct bpf_array, map);
831 for (i = 0; i < array->map.max_entries; i++)
832 fd_array_map_delete_elem(map, &i);
835 static void prog_array_map_seq_show_elem(struct bpf_map *map, void *key,
843 elem = array_map_lookup_elem(map, key);
845 ptr = READ_ONCE(*elem);
847 seq_printf(m, "%u: ", *(u32 *)key);
848 prog_id = prog_fd_array_sys_lookup_elem(ptr);
849 btf_type_seq_show(map->btf, map->btf_value_type_id,
858 struct prog_poke_elem {
859 struct list_head list;
860 struct bpf_prog_aux *aux;
863 static int prog_array_map_poke_track(struct bpf_map *map,
864 struct bpf_prog_aux *prog_aux)
866 struct prog_poke_elem *elem;
867 struct bpf_array_aux *aux;
870 aux = container_of(map, struct bpf_array, map)->aux;
871 mutex_lock(&aux->poke_mutex);
872 list_for_each_entry(elem, &aux->poke_progs, list) {
873 if (elem->aux == prog_aux)
877 elem = kmalloc(sizeof(*elem), GFP_KERNEL);
883 INIT_LIST_HEAD(&elem->list);
884 /* We must track the program's aux info at this point in time
885 * since the program pointer itself may not be stable yet, see
886 * also comment in prog_array_map_poke_run().
888 elem->aux = prog_aux;
890 list_add_tail(&elem->list, &aux->poke_progs);
892 mutex_unlock(&aux->poke_mutex);
896 static void prog_array_map_poke_untrack(struct bpf_map *map,
897 struct bpf_prog_aux *prog_aux)
899 struct prog_poke_elem *elem, *tmp;
900 struct bpf_array_aux *aux;
902 aux = container_of(map, struct bpf_array, map)->aux;
903 mutex_lock(&aux->poke_mutex);
904 list_for_each_entry_safe(elem, tmp, &aux->poke_progs, list) {
905 if (elem->aux == prog_aux) {
906 list_del_init(&elem->list);
911 mutex_unlock(&aux->poke_mutex);
914 static void prog_array_map_poke_run(struct bpf_map *map, u32 key,
915 struct bpf_prog *old,
916 struct bpf_prog *new)
918 u8 *old_addr, *new_addr, *old_bypass_addr;
919 struct prog_poke_elem *elem;
920 struct bpf_array_aux *aux;
922 aux = container_of(map, struct bpf_array, map)->aux;
923 WARN_ON_ONCE(!mutex_is_locked(&aux->poke_mutex));
925 list_for_each_entry(elem, &aux->poke_progs, list) {
926 struct bpf_jit_poke_descriptor *poke;
929 for (i = 0; i < elem->aux->size_poke_tab; i++) {
930 poke = &elem->aux->poke_tab[i];
932 /* Few things to be aware of:
934 * 1) We can only ever access aux in this context, but
935 * not aux->prog since it might not be stable yet and
936 * there could be danger of use after free otherwise.
937 * 2) Initially when we start tracking aux, the program
938 * is not JITed yet and also does not have a kallsyms
939 * entry. We skip these as poke->tailcall_target_stable
940 * is not active yet. The JIT will do the final fixup
941 * before setting it stable. The various
942 * poke->tailcall_target_stable are successively
943 * activated, so tail call updates can arrive from here
944 * while JIT is still finishing its final fixup for
945 * non-activated poke entries.
946 * 3) On program teardown, the program's kallsym entry gets
947 * removed out of RCU callback, but we can only untrack
948 * from sleepable context, therefore bpf_arch_text_poke()
949 * might not see that this is in BPF text section and
950 * bails out with -EINVAL. As these are unreachable since
951 * RCU grace period already passed, we simply skip them.
952 * 4) Also programs reaching refcount of zero while patching
953 * is in progress is okay since we're protected under
954 * poke_mutex and untrack the programs before the JIT
955 * buffer is freed. When we're still in the middle of
956 * patching and suddenly kallsyms entry of the program
957 * gets evicted, we just skip the rest which is fine due
959 * 5) Any other error happening below from bpf_arch_text_poke()
960 * is a unexpected bug.
962 if (!READ_ONCE(poke->tailcall_target_stable))
964 if (poke->reason != BPF_POKE_REASON_TAIL_CALL)
966 if (poke->tail_call.map != map ||
967 poke->tail_call.key != key)
970 old_bypass_addr = old ? NULL : poke->bypass_addr;
971 old_addr = old ? (u8 *)old->bpf_func + poke->adj_off : NULL;
972 new_addr = new ? (u8 *)new->bpf_func + poke->adj_off : NULL;
975 ret = bpf_arch_text_poke(poke->tailcall_target,
978 BUG_ON(ret < 0 && ret != -EINVAL);
980 ret = bpf_arch_text_poke(poke->tailcall_bypass,
984 BUG_ON(ret < 0 && ret != -EINVAL);
987 ret = bpf_arch_text_poke(poke->tailcall_bypass,
991 BUG_ON(ret < 0 && ret != -EINVAL);
992 /* let other CPUs finish the execution of program
993 * so that it will not possible to expose them
994 * to invalid nop, stack unwind, nop state
998 ret = bpf_arch_text_poke(poke->tailcall_target,
1001 BUG_ON(ret < 0 && ret != -EINVAL);
1007 static void prog_array_map_clear_deferred(struct work_struct *work)
1009 struct bpf_map *map = container_of(work, struct bpf_array_aux,
1011 bpf_fd_array_map_clear(map);
1015 static void prog_array_map_clear(struct bpf_map *map)
1017 struct bpf_array_aux *aux = container_of(map, struct bpf_array,
1020 schedule_work(&aux->work);
1023 static struct bpf_map *prog_array_map_alloc(union bpf_attr *attr)
1025 struct bpf_array_aux *aux;
1026 struct bpf_map *map;
1028 aux = kzalloc(sizeof(*aux), GFP_KERNEL);
1030 return ERR_PTR(-ENOMEM);
1032 INIT_WORK(&aux->work, prog_array_map_clear_deferred);
1033 INIT_LIST_HEAD(&aux->poke_progs);
1034 mutex_init(&aux->poke_mutex);
1035 spin_lock_init(&aux->owner.lock);
1037 map = array_map_alloc(attr);
1043 container_of(map, struct bpf_array, map)->aux = aux;
1049 static void prog_array_map_free(struct bpf_map *map)
1051 struct prog_poke_elem *elem, *tmp;
1052 struct bpf_array_aux *aux;
1054 aux = container_of(map, struct bpf_array, map)->aux;
1055 list_for_each_entry_safe(elem, tmp, &aux->poke_progs, list) {
1056 list_del_init(&elem->list);
1060 fd_array_map_free(map);
1063 /* prog_array->aux->{type,jited} is a runtime binding.
1064 * Doing static check alone in the verifier is not enough.
1065 * Thus, prog_array_map cannot be used as an inner_map
1066 * and map_meta_equal is not implemented.
1068 static int prog_array_map_btf_id;
1069 const struct bpf_map_ops prog_array_map_ops = {
1070 .map_alloc_check = fd_array_map_alloc_check,
1071 .map_alloc = prog_array_map_alloc,
1072 .map_free = prog_array_map_free,
1073 .map_poke_track = prog_array_map_poke_track,
1074 .map_poke_untrack = prog_array_map_poke_untrack,
1075 .map_poke_run = prog_array_map_poke_run,
1076 .map_get_next_key = array_map_get_next_key,
1077 .map_lookup_elem = fd_array_map_lookup_elem,
1078 .map_delete_elem = fd_array_map_delete_elem,
1079 .map_fd_get_ptr = prog_fd_array_get_ptr,
1080 .map_fd_put_ptr = prog_fd_array_put_ptr,
1081 .map_fd_sys_lookup_elem = prog_fd_array_sys_lookup_elem,
1082 .map_release_uref = prog_array_map_clear,
1083 .map_seq_show_elem = prog_array_map_seq_show_elem,
1084 .map_btf_name = "bpf_array",
1085 .map_btf_id = &prog_array_map_btf_id,
1088 static struct bpf_event_entry *bpf_event_entry_gen(struct file *perf_file,
1089 struct file *map_file)
1091 struct bpf_event_entry *ee;
1093 ee = kzalloc(sizeof(*ee), GFP_ATOMIC);
1095 ee->event = perf_file->private_data;
1096 ee->perf_file = perf_file;
1097 ee->map_file = map_file;
1103 static void __bpf_event_entry_free(struct rcu_head *rcu)
1105 struct bpf_event_entry *ee;
1107 ee = container_of(rcu, struct bpf_event_entry, rcu);
1108 fput(ee->perf_file);
1112 static void bpf_event_entry_free_rcu(struct bpf_event_entry *ee)
1114 call_rcu(&ee->rcu, __bpf_event_entry_free);
1117 static void *perf_event_fd_array_get_ptr(struct bpf_map *map,
1118 struct file *map_file, int fd)
1120 struct bpf_event_entry *ee;
1121 struct perf_event *event;
1122 struct file *perf_file;
1125 perf_file = perf_event_get(fd);
1126 if (IS_ERR(perf_file))
1129 ee = ERR_PTR(-EOPNOTSUPP);
1130 event = perf_file->private_data;
1131 if (perf_event_read_local(event, &value, NULL, NULL) == -EOPNOTSUPP)
1134 ee = bpf_event_entry_gen(perf_file, map_file);
1137 ee = ERR_PTR(-ENOMEM);
1143 static void perf_event_fd_array_put_ptr(struct bpf_map *map, void *ptr, bool need_defer)
1145 /* bpf_perf_event is freed after one RCU grace period */
1146 bpf_event_entry_free_rcu(ptr);
1149 static void perf_event_fd_array_release(struct bpf_map *map,
1150 struct file *map_file)
1152 struct bpf_array *array = container_of(map, struct bpf_array, map);
1153 struct bpf_event_entry *ee;
1156 if (map->map_flags & BPF_F_PRESERVE_ELEMS)
1160 for (i = 0; i < array->map.max_entries; i++) {
1161 ee = READ_ONCE(array->ptrs[i]);
1162 if (ee && ee->map_file == map_file)
1163 fd_array_map_delete_elem(map, &i);
1168 static void perf_event_fd_array_map_free(struct bpf_map *map)
1170 if (map->map_flags & BPF_F_PRESERVE_ELEMS)
1171 bpf_fd_array_map_clear(map);
1172 fd_array_map_free(map);
1175 static int perf_event_array_map_btf_id;
1176 const struct bpf_map_ops perf_event_array_map_ops = {
1177 .map_meta_equal = bpf_map_meta_equal,
1178 .map_alloc_check = fd_array_map_alloc_check,
1179 .map_alloc = array_map_alloc,
1180 .map_free = perf_event_fd_array_map_free,
1181 .map_get_next_key = array_map_get_next_key,
1182 .map_lookup_elem = fd_array_map_lookup_elem,
1183 .map_delete_elem = fd_array_map_delete_elem,
1184 .map_fd_get_ptr = perf_event_fd_array_get_ptr,
1185 .map_fd_put_ptr = perf_event_fd_array_put_ptr,
1186 .map_release = perf_event_fd_array_release,
1187 .map_check_btf = map_check_no_btf,
1188 .map_btf_name = "bpf_array",
1189 .map_btf_id = &perf_event_array_map_btf_id,
1192 #ifdef CONFIG_CGROUPS
1193 static void *cgroup_fd_array_get_ptr(struct bpf_map *map,
1194 struct file *map_file /* not used */,
1197 return cgroup_get_from_fd(fd);
1200 static void cgroup_fd_array_put_ptr(struct bpf_map *map, void *ptr, bool need_defer)
1202 /* cgroup_put free cgrp after a rcu grace period */
1206 static void cgroup_fd_array_free(struct bpf_map *map)
1208 bpf_fd_array_map_clear(map);
1209 fd_array_map_free(map);
1212 static int cgroup_array_map_btf_id;
1213 const struct bpf_map_ops cgroup_array_map_ops = {
1214 .map_meta_equal = bpf_map_meta_equal,
1215 .map_alloc_check = fd_array_map_alloc_check,
1216 .map_alloc = array_map_alloc,
1217 .map_free = cgroup_fd_array_free,
1218 .map_get_next_key = array_map_get_next_key,
1219 .map_lookup_elem = fd_array_map_lookup_elem,
1220 .map_delete_elem = fd_array_map_delete_elem,
1221 .map_fd_get_ptr = cgroup_fd_array_get_ptr,
1222 .map_fd_put_ptr = cgroup_fd_array_put_ptr,
1223 .map_check_btf = map_check_no_btf,
1224 .map_btf_name = "bpf_array",
1225 .map_btf_id = &cgroup_array_map_btf_id,
1229 static struct bpf_map *array_of_map_alloc(union bpf_attr *attr)
1231 struct bpf_map *map, *inner_map_meta;
1233 inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
1234 if (IS_ERR(inner_map_meta))
1235 return inner_map_meta;
1237 map = array_map_alloc(attr);
1239 bpf_map_meta_free(inner_map_meta);
1243 map->inner_map_meta = inner_map_meta;
1248 static void array_of_map_free(struct bpf_map *map)
1250 /* map->inner_map_meta is only accessed by syscall which
1251 * is protected by fdget/fdput.
1253 bpf_map_meta_free(map->inner_map_meta);
1254 bpf_fd_array_map_clear(map);
1255 fd_array_map_free(map);
1258 static void *array_of_map_lookup_elem(struct bpf_map *map, void *key)
1260 struct bpf_map **inner_map = array_map_lookup_elem(map, key);
1265 return READ_ONCE(*inner_map);
1268 static int array_of_map_gen_lookup(struct bpf_map *map,
1269 struct bpf_insn *insn_buf)
1271 struct bpf_array *array = container_of(map, struct bpf_array, map);
1272 u32 elem_size = round_up(map->value_size, 8);
1273 struct bpf_insn *insn = insn_buf;
1274 const int ret = BPF_REG_0;
1275 const int map_ptr = BPF_REG_1;
1276 const int index = BPF_REG_2;
1278 *insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
1279 *insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
1280 if (!map->bypass_spec_v1) {
1281 *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 6);
1282 *insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
1284 *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 5);
1286 if (is_power_of_2(elem_size))
1287 *insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(elem_size));
1289 *insn++ = BPF_ALU64_IMM(BPF_MUL, ret, elem_size);
1290 *insn++ = BPF_ALU64_REG(BPF_ADD, ret, map_ptr);
1291 *insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0);
1292 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1);
1293 *insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
1294 *insn++ = BPF_MOV64_IMM(ret, 0);
1296 return insn - insn_buf;
1299 static int array_of_maps_map_btf_id;
1300 const struct bpf_map_ops array_of_maps_map_ops = {
1301 .map_alloc_check = fd_array_map_alloc_check,
1302 .map_alloc = array_of_map_alloc,
1303 .map_free = array_of_map_free,
1304 .map_get_next_key = array_map_get_next_key,
1305 .map_lookup_elem = array_of_map_lookup_elem,
1306 .map_delete_elem = fd_array_map_delete_elem,
1307 .map_fd_get_ptr = bpf_map_fd_get_ptr,
1308 .map_fd_put_ptr = bpf_map_fd_put_ptr,
1309 .map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
1310 .map_gen_lookup = array_of_map_gen_lookup,
1311 .map_check_btf = map_check_no_btf,
1312 .map_btf_name = "bpf_array",
1313 .map_btf_id = &array_of_maps_map_btf_id,