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![Kumar Kartikeya Dwivedi](/assets/img/avatar_default.png)
Since the commit being fixed, we now miss freeing btf_record for local
storage maps which will have a btf_record populated in case they have
bpf_spin_lock element.
This was missed because I made the choice of offloading the job to free
kptr_off_tab (now btf_record) to the map_free callback when adding
support for kptrs.
Revisiting the reason for this decision, there is the possibility that
the btf_record gets used inside map_free callback (e.g. in case of maps
embedding kptrs) to iterate over them and free them, hence doing it
before the map_free callback would be leaking special field memory, and
do invalid memory access. The btf_record keeps module references which
is critical to ensure the dtor call made for referenced kptr is safe to
do.
If doing it after map_free callback, the map area is already freed, so
we cannot access bpf_map structure anymore.
To fix this and prevent such lapses in future, move bpf_map_free_record
out of the map_free callback, and do it after map_free by remembering
the btf_record pointer. There is no need to access bpf_map structure in
that case, and we can avoid missing this case when support for new map
types is added for other special fields.
Since a btf_record and its btf_field_offs are used together, for
consistency delay freeing of field_offs as well. While not a problem
right now, a lot of code assumes that either both record and field_offs
are set or none at once.
Note that in case of map of maps (outer maps), inner_map_meta->record is
only used during verification, not to free fields in map value, hence we
simply keep the bpf_map_free_record call as is in bpf_map_meta_free and
never touch map->inner_map_meta in bpf_map_free_deferred.
Add a comment making note of these details.
Fixes: db55911782
("bpf: Consolidate spin_lock, timer management into btf_record")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
1383 lines
37 KiB
C
1383 lines
37 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
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* Copyright (c) 2016,2017 Facebook
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*/
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#include <linux/bpf.h>
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#include <linux/btf.h>
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#include <linux/err.h>
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#include <linux/slab.h>
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#include <linux/mm.h>
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#include <linux/filter.h>
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#include <linux/perf_event.h>
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#include <uapi/linux/btf.h>
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#include <linux/rcupdate_trace.h>
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#include <linux/btf_ids.h>
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#include "map_in_map.h"
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#define ARRAY_CREATE_FLAG_MASK \
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(BPF_F_NUMA_NODE | BPF_F_MMAPABLE | BPF_F_ACCESS_MASK | \
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BPF_F_PRESERVE_ELEMS | BPF_F_INNER_MAP)
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static void bpf_array_free_percpu(struct bpf_array *array)
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{
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int i;
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for (i = 0; i < array->map.max_entries; i++) {
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free_percpu(array->pptrs[i]);
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cond_resched();
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}
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}
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static int bpf_array_alloc_percpu(struct bpf_array *array)
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{
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void __percpu *ptr;
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int i;
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for (i = 0; i < array->map.max_entries; i++) {
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ptr = bpf_map_alloc_percpu(&array->map, array->elem_size, 8,
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GFP_USER | __GFP_NOWARN);
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if (!ptr) {
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bpf_array_free_percpu(array);
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return -ENOMEM;
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}
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array->pptrs[i] = ptr;
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cond_resched();
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}
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return 0;
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}
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/* Called from syscall */
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int array_map_alloc_check(union bpf_attr *attr)
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{
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bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
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int numa_node = bpf_map_attr_numa_node(attr);
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/* check sanity of attributes */
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if (attr->max_entries == 0 || attr->key_size != 4 ||
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attr->value_size == 0 ||
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attr->map_flags & ~ARRAY_CREATE_FLAG_MASK ||
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!bpf_map_flags_access_ok(attr->map_flags) ||
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(percpu && numa_node != NUMA_NO_NODE))
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return -EINVAL;
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if (attr->map_type != BPF_MAP_TYPE_ARRAY &&
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attr->map_flags & (BPF_F_MMAPABLE | BPF_F_INNER_MAP))
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return -EINVAL;
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if (attr->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY &&
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attr->map_flags & BPF_F_PRESERVE_ELEMS)
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return -EINVAL;
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/* avoid overflow on round_up(map->value_size) */
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if (attr->value_size > INT_MAX)
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return -E2BIG;
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return 0;
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}
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static struct bpf_map *array_map_alloc(union bpf_attr *attr)
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{
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bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
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int numa_node = bpf_map_attr_numa_node(attr);
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u32 elem_size, index_mask, max_entries;
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bool bypass_spec_v1 = bpf_bypass_spec_v1();
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u64 array_size, mask64;
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struct bpf_array *array;
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elem_size = round_up(attr->value_size, 8);
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max_entries = attr->max_entries;
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/* On 32 bit archs roundup_pow_of_two() with max_entries that has
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* upper most bit set in u32 space is undefined behavior due to
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* resulting 1U << 32, so do it manually here in u64 space.
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*/
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mask64 = fls_long(max_entries - 1);
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mask64 = 1ULL << mask64;
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mask64 -= 1;
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index_mask = mask64;
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if (!bypass_spec_v1) {
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/* round up array size to nearest power of 2,
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* since cpu will speculate within index_mask limits
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*/
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max_entries = index_mask + 1;
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/* Check for overflows. */
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if (max_entries < attr->max_entries)
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return ERR_PTR(-E2BIG);
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}
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array_size = sizeof(*array);
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if (percpu) {
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array_size += (u64) max_entries * sizeof(void *);
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} else {
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/* rely on vmalloc() to return page-aligned memory and
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* ensure array->value is exactly page-aligned
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*/
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if (attr->map_flags & BPF_F_MMAPABLE) {
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array_size = PAGE_ALIGN(array_size);
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array_size += PAGE_ALIGN((u64) max_entries * elem_size);
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} else {
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array_size += (u64) max_entries * elem_size;
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}
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}
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/* allocate all map elements and zero-initialize them */
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if (attr->map_flags & BPF_F_MMAPABLE) {
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void *data;
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/* kmalloc'ed memory can't be mmap'ed, use explicit vmalloc */
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data = bpf_map_area_mmapable_alloc(array_size, numa_node);
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if (!data)
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return ERR_PTR(-ENOMEM);
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array = data + PAGE_ALIGN(sizeof(struct bpf_array))
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- offsetof(struct bpf_array, value);
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} else {
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array = bpf_map_area_alloc(array_size, numa_node);
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}
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if (!array)
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return ERR_PTR(-ENOMEM);
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array->index_mask = index_mask;
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array->map.bypass_spec_v1 = bypass_spec_v1;
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/* copy mandatory map attributes */
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bpf_map_init_from_attr(&array->map, attr);
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array->elem_size = elem_size;
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if (percpu && bpf_array_alloc_percpu(array)) {
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bpf_map_area_free(array);
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return ERR_PTR(-ENOMEM);
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}
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return &array->map;
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}
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static void *array_map_elem_ptr(struct bpf_array* array, u32 index)
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{
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return array->value + (u64)array->elem_size * index;
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}
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/* Called from syscall or from eBPF program */
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static void *array_map_lookup_elem(struct bpf_map *map, void *key)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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u32 index = *(u32 *)key;
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if (unlikely(index >= array->map.max_entries))
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return NULL;
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return array->value + (u64)array->elem_size * (index & array->index_mask);
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}
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static int array_map_direct_value_addr(const struct bpf_map *map, u64 *imm,
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u32 off)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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if (map->max_entries != 1)
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return -ENOTSUPP;
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if (off >= map->value_size)
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return -EINVAL;
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*imm = (unsigned long)array->value;
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return 0;
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}
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static int array_map_direct_value_meta(const struct bpf_map *map, u64 imm,
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u32 *off)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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u64 base = (unsigned long)array->value;
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u64 range = array->elem_size;
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if (map->max_entries != 1)
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return -ENOTSUPP;
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if (imm < base || imm >= base + range)
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return -ENOENT;
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*off = imm - base;
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return 0;
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}
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/* emit BPF instructions equivalent to C code of array_map_lookup_elem() */
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static int array_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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struct bpf_insn *insn = insn_buf;
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u32 elem_size = array->elem_size;
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const int ret = BPF_REG_0;
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const int map_ptr = BPF_REG_1;
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const int index = BPF_REG_2;
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if (map->map_flags & BPF_F_INNER_MAP)
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return -EOPNOTSUPP;
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*insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
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*insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
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if (!map->bypass_spec_v1) {
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*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 4);
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*insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
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} else {
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*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 3);
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}
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if (is_power_of_2(elem_size)) {
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*insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(elem_size));
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} else {
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*insn++ = BPF_ALU64_IMM(BPF_MUL, ret, elem_size);
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}
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*insn++ = BPF_ALU64_REG(BPF_ADD, ret, map_ptr);
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*insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
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*insn++ = BPF_MOV64_IMM(ret, 0);
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return insn - insn_buf;
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}
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/* Called from eBPF program */
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static void *percpu_array_map_lookup_elem(struct bpf_map *map, void *key)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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u32 index = *(u32 *)key;
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if (unlikely(index >= array->map.max_entries))
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return NULL;
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return this_cpu_ptr(array->pptrs[index & array->index_mask]);
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}
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static void *percpu_array_map_lookup_percpu_elem(struct bpf_map *map, void *key, u32 cpu)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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u32 index = *(u32 *)key;
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if (cpu >= nr_cpu_ids)
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return NULL;
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if (unlikely(index >= array->map.max_entries))
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return NULL;
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return per_cpu_ptr(array->pptrs[index & array->index_mask], cpu);
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}
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int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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u32 index = *(u32 *)key;
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void __percpu *pptr;
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int cpu, off = 0;
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u32 size;
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if (unlikely(index >= array->map.max_entries))
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return -ENOENT;
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/* per_cpu areas are zero-filled and bpf programs can only
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* access 'value_size' of them, so copying rounded areas
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* will not leak any kernel data
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*/
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size = array->elem_size;
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rcu_read_lock();
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pptr = array->pptrs[index & array->index_mask];
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for_each_possible_cpu(cpu) {
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copy_map_value_long(map, value + off, per_cpu_ptr(pptr, cpu));
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check_and_init_map_value(map, value + off);
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off += size;
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}
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rcu_read_unlock();
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return 0;
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}
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/* Called from syscall */
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static int array_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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u32 index = key ? *(u32 *)key : U32_MAX;
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u32 *next = (u32 *)next_key;
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if (index >= array->map.max_entries) {
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*next = 0;
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return 0;
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}
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if (index == array->map.max_entries - 1)
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return -ENOENT;
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*next = index + 1;
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return 0;
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}
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/* Called from syscall or from eBPF program */
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static int array_map_update_elem(struct bpf_map *map, void *key, void *value,
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u64 map_flags)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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u32 index = *(u32 *)key;
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char *val;
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if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST))
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/* unknown flags */
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return -EINVAL;
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if (unlikely(index >= array->map.max_entries))
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/* all elements were pre-allocated, cannot insert a new one */
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return -E2BIG;
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if (unlikely(map_flags & BPF_NOEXIST))
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/* all elements already exist */
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return -EEXIST;
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if (unlikely((map_flags & BPF_F_LOCK) &&
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!btf_record_has_field(map->record, BPF_SPIN_LOCK)))
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return -EINVAL;
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if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
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val = this_cpu_ptr(array->pptrs[index & array->index_mask]);
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copy_map_value(map, val, value);
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bpf_obj_free_fields(array->map.record, val);
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} else {
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val = array->value +
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(u64)array->elem_size * (index & array->index_mask);
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if (map_flags & BPF_F_LOCK)
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copy_map_value_locked(map, val, value, false);
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else
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copy_map_value(map, val, value);
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bpf_obj_free_fields(array->map.record, val);
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}
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return 0;
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}
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int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
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u64 map_flags)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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u32 index = *(u32 *)key;
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void __percpu *pptr;
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int cpu, off = 0;
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u32 size;
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if (unlikely(map_flags > BPF_EXIST))
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/* unknown flags */
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return -EINVAL;
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if (unlikely(index >= array->map.max_entries))
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/* all elements were pre-allocated, cannot insert a new one */
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return -E2BIG;
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if (unlikely(map_flags == BPF_NOEXIST))
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/* all elements already exist */
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return -EEXIST;
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/* the user space will provide round_up(value_size, 8) bytes that
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* will be copied into per-cpu area. bpf programs can only access
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* value_size of it. During lookup the same extra bytes will be
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* returned or zeros which were zero-filled by percpu_alloc,
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* so no kernel data leaks possible
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*/
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size = array->elem_size;
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rcu_read_lock();
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pptr = array->pptrs[index & array->index_mask];
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for_each_possible_cpu(cpu) {
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copy_map_value_long(map, per_cpu_ptr(pptr, cpu), value + off);
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bpf_obj_free_fields(array->map.record, per_cpu_ptr(pptr, cpu));
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off += size;
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}
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rcu_read_unlock();
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return 0;
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}
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/* Called from syscall or from eBPF program */
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static int array_map_delete_elem(struct bpf_map *map, void *key)
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{
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return -EINVAL;
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}
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static void *array_map_vmalloc_addr(struct bpf_array *array)
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{
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return (void *)round_down((unsigned long)array, PAGE_SIZE);
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}
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static void array_map_free_timers(struct bpf_map *map)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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int i;
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/* We don't reset or free fields other than timer on uref dropping to zero. */
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if (!btf_record_has_field(map->record, BPF_TIMER))
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return;
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for (i = 0; i < array->map.max_entries; i++)
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bpf_obj_free_timer(map->record, array_map_elem_ptr(array, i));
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}
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/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
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static void array_map_free(struct bpf_map *map)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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int i;
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if (!IS_ERR_OR_NULL(map->record)) {
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if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
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for (i = 0; i < array->map.max_entries; i++) {
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void __percpu *pptr = array->pptrs[i & array->index_mask];
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int cpu;
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for_each_possible_cpu(cpu) {
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bpf_obj_free_fields(map->record, per_cpu_ptr(pptr, cpu));
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cond_resched();
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}
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}
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} else {
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for (i = 0; i < array->map.max_entries; i++)
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bpf_obj_free_fields(map->record, array_map_elem_ptr(array, i));
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}
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}
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if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
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bpf_array_free_percpu(array);
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if (array->map.map_flags & BPF_F_MMAPABLE)
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bpf_map_area_free(array_map_vmalloc_addr(array));
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else
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bpf_map_area_free(array);
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}
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|
|
|
static void array_map_seq_show_elem(struct bpf_map *map, void *key,
|
|
struct seq_file *m)
|
|
{
|
|
void *value;
|
|
|
|
rcu_read_lock();
|
|
|
|
value = array_map_lookup_elem(map, key);
|
|
if (!value) {
|
|
rcu_read_unlock();
|
|
return;
|
|
}
|
|
|
|
if (map->btf_key_type_id)
|
|
seq_printf(m, "%u: ", *(u32 *)key);
|
|
btf_type_seq_show(map->btf, map->btf_value_type_id, value, m);
|
|
seq_puts(m, "\n");
|
|
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
static void percpu_array_map_seq_show_elem(struct bpf_map *map, void *key,
|
|
struct seq_file *m)
|
|
{
|
|
struct bpf_array *array = container_of(map, struct bpf_array, map);
|
|
u32 index = *(u32 *)key;
|
|
void __percpu *pptr;
|
|
int cpu;
|
|
|
|
rcu_read_lock();
|
|
|
|
seq_printf(m, "%u: {\n", *(u32 *)key);
|
|
pptr = array->pptrs[index & array->index_mask];
|
|
for_each_possible_cpu(cpu) {
|
|
seq_printf(m, "\tcpu%d: ", cpu);
|
|
btf_type_seq_show(map->btf, map->btf_value_type_id,
|
|
per_cpu_ptr(pptr, cpu), m);
|
|
seq_puts(m, "\n");
|
|
}
|
|
seq_puts(m, "}\n");
|
|
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
static int array_map_check_btf(const struct bpf_map *map,
|
|
const struct btf *btf,
|
|
const struct btf_type *key_type,
|
|
const struct btf_type *value_type)
|
|
{
|
|
u32 int_data;
|
|
|
|
/* One exception for keyless BTF: .bss/.data/.rodata map */
|
|
if (btf_type_is_void(key_type)) {
|
|
if (map->map_type != BPF_MAP_TYPE_ARRAY ||
|
|
map->max_entries != 1)
|
|
return -EINVAL;
|
|
|
|
if (BTF_INFO_KIND(value_type->info) != BTF_KIND_DATASEC)
|
|
return -EINVAL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
if (BTF_INFO_KIND(key_type->info) != BTF_KIND_INT)
|
|
return -EINVAL;
|
|
|
|
int_data = *(u32 *)(key_type + 1);
|
|
/* bpf array can only take a u32 key. This check makes sure
|
|
* that the btf matches the attr used during map_create.
|
|
*/
|
|
if (BTF_INT_BITS(int_data) != 32 || BTF_INT_OFFSET(int_data))
|
|
return -EINVAL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int array_map_mmap(struct bpf_map *map, struct vm_area_struct *vma)
|
|
{
|
|
struct bpf_array *array = container_of(map, struct bpf_array, map);
|
|
pgoff_t pgoff = PAGE_ALIGN(sizeof(*array)) >> PAGE_SHIFT;
|
|
|
|
if (!(map->map_flags & BPF_F_MMAPABLE))
|
|
return -EINVAL;
|
|
|
|
if (vma->vm_pgoff * PAGE_SIZE + (vma->vm_end - vma->vm_start) >
|
|
PAGE_ALIGN((u64)array->map.max_entries * array->elem_size))
|
|
return -EINVAL;
|
|
|
|
return remap_vmalloc_range(vma, array_map_vmalloc_addr(array),
|
|
vma->vm_pgoff + pgoff);
|
|
}
|
|
|
|
static bool array_map_meta_equal(const struct bpf_map *meta0,
|
|
const struct bpf_map *meta1)
|
|
{
|
|
if (!bpf_map_meta_equal(meta0, meta1))
|
|
return false;
|
|
return meta0->map_flags & BPF_F_INNER_MAP ? true :
|
|
meta0->max_entries == meta1->max_entries;
|
|
}
|
|
|
|
struct bpf_iter_seq_array_map_info {
|
|
struct bpf_map *map;
|
|
void *percpu_value_buf;
|
|
u32 index;
|
|
};
|
|
|
|
static void *bpf_array_map_seq_start(struct seq_file *seq, loff_t *pos)
|
|
{
|
|
struct bpf_iter_seq_array_map_info *info = seq->private;
|
|
struct bpf_map *map = info->map;
|
|
struct bpf_array *array;
|
|
u32 index;
|
|
|
|
if (info->index >= map->max_entries)
|
|
return NULL;
|
|
|
|
if (*pos == 0)
|
|
++*pos;
|
|
array = container_of(map, struct bpf_array, map);
|
|
index = info->index & array->index_mask;
|
|
if (info->percpu_value_buf)
|
|
return array->pptrs[index];
|
|
return array_map_elem_ptr(array, index);
|
|
}
|
|
|
|
static void *bpf_array_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
|
|
{
|
|
struct bpf_iter_seq_array_map_info *info = seq->private;
|
|
struct bpf_map *map = info->map;
|
|
struct bpf_array *array;
|
|
u32 index;
|
|
|
|
++*pos;
|
|
++info->index;
|
|
if (info->index >= map->max_entries)
|
|
return NULL;
|
|
|
|
array = container_of(map, struct bpf_array, map);
|
|
index = info->index & array->index_mask;
|
|
if (info->percpu_value_buf)
|
|
return array->pptrs[index];
|
|
return array_map_elem_ptr(array, index);
|
|
}
|
|
|
|
static int __bpf_array_map_seq_show(struct seq_file *seq, void *v)
|
|
{
|
|
struct bpf_iter_seq_array_map_info *info = seq->private;
|
|
struct bpf_iter__bpf_map_elem ctx = {};
|
|
struct bpf_map *map = info->map;
|
|
struct bpf_array *array = container_of(map, struct bpf_array, map);
|
|
struct bpf_iter_meta meta;
|
|
struct bpf_prog *prog;
|
|
int off = 0, cpu = 0;
|
|
void __percpu **pptr;
|
|
u32 size;
|
|
|
|
meta.seq = seq;
|
|
prog = bpf_iter_get_info(&meta, v == NULL);
|
|
if (!prog)
|
|
return 0;
|
|
|
|
ctx.meta = &meta;
|
|
ctx.map = info->map;
|
|
if (v) {
|
|
ctx.key = &info->index;
|
|
|
|
if (!info->percpu_value_buf) {
|
|
ctx.value = v;
|
|
} else {
|
|
pptr = v;
|
|
size = array->elem_size;
|
|
for_each_possible_cpu(cpu) {
|
|
copy_map_value_long(map, info->percpu_value_buf + off,
|
|
per_cpu_ptr(pptr, cpu));
|
|
check_and_init_map_value(map, info->percpu_value_buf + off);
|
|
off += size;
|
|
}
|
|
ctx.value = info->percpu_value_buf;
|
|
}
|
|
}
|
|
|
|
return bpf_iter_run_prog(prog, &ctx);
|
|
}
|
|
|
|
static int bpf_array_map_seq_show(struct seq_file *seq, void *v)
|
|
{
|
|
return __bpf_array_map_seq_show(seq, v);
|
|
}
|
|
|
|
static void bpf_array_map_seq_stop(struct seq_file *seq, void *v)
|
|
{
|
|
if (!v)
|
|
(void)__bpf_array_map_seq_show(seq, NULL);
|
|
}
|
|
|
|
static int bpf_iter_init_array_map(void *priv_data,
|
|
struct bpf_iter_aux_info *aux)
|
|
{
|
|
struct bpf_iter_seq_array_map_info *seq_info = priv_data;
|
|
struct bpf_map *map = aux->map;
|
|
struct bpf_array *array = container_of(map, struct bpf_array, map);
|
|
void *value_buf;
|
|
u32 buf_size;
|
|
|
|
if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
|
|
buf_size = array->elem_size * num_possible_cpus();
|
|
value_buf = kmalloc(buf_size, GFP_USER | __GFP_NOWARN);
|
|
if (!value_buf)
|
|
return -ENOMEM;
|
|
|
|
seq_info->percpu_value_buf = value_buf;
|
|
}
|
|
|
|
/* bpf_iter_attach_map() acquires a map uref, and the uref may be
|
|
* released before or in the middle of iterating map elements, so
|
|
* acquire an extra map uref for iterator.
|
|
*/
|
|
bpf_map_inc_with_uref(map);
|
|
seq_info->map = map;
|
|
return 0;
|
|
}
|
|
|
|
static void bpf_iter_fini_array_map(void *priv_data)
|
|
{
|
|
struct bpf_iter_seq_array_map_info *seq_info = priv_data;
|
|
|
|
bpf_map_put_with_uref(seq_info->map);
|
|
kfree(seq_info->percpu_value_buf);
|
|
}
|
|
|
|
static const struct seq_operations bpf_array_map_seq_ops = {
|
|
.start = bpf_array_map_seq_start,
|
|
.next = bpf_array_map_seq_next,
|
|
.stop = bpf_array_map_seq_stop,
|
|
.show = bpf_array_map_seq_show,
|
|
};
|
|
|
|
static const struct bpf_iter_seq_info iter_seq_info = {
|
|
.seq_ops = &bpf_array_map_seq_ops,
|
|
.init_seq_private = bpf_iter_init_array_map,
|
|
.fini_seq_private = bpf_iter_fini_array_map,
|
|
.seq_priv_size = sizeof(struct bpf_iter_seq_array_map_info),
|
|
};
|
|
|
|
static int bpf_for_each_array_elem(struct bpf_map *map, bpf_callback_t callback_fn,
|
|
void *callback_ctx, u64 flags)
|
|
{
|
|
u32 i, key, num_elems = 0;
|
|
struct bpf_array *array;
|
|
bool is_percpu;
|
|
u64 ret = 0;
|
|
void *val;
|
|
|
|
if (flags != 0)
|
|
return -EINVAL;
|
|
|
|
is_percpu = map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
|
|
array = container_of(map, struct bpf_array, map);
|
|
if (is_percpu)
|
|
migrate_disable();
|
|
for (i = 0; i < map->max_entries; i++) {
|
|
if (is_percpu)
|
|
val = this_cpu_ptr(array->pptrs[i]);
|
|
else
|
|
val = array_map_elem_ptr(array, i);
|
|
num_elems++;
|
|
key = i;
|
|
ret = callback_fn((u64)(long)map, (u64)(long)&key,
|
|
(u64)(long)val, (u64)(long)callback_ctx, 0);
|
|
/* return value: 0 - continue, 1 - stop and return */
|
|
if (ret)
|
|
break;
|
|
}
|
|
|
|
if (is_percpu)
|
|
migrate_enable();
|
|
return num_elems;
|
|
}
|
|
|
|
BTF_ID_LIST_SINGLE(array_map_btf_ids, struct, bpf_array)
|
|
const struct bpf_map_ops array_map_ops = {
|
|
.map_meta_equal = array_map_meta_equal,
|
|
.map_alloc_check = array_map_alloc_check,
|
|
.map_alloc = array_map_alloc,
|
|
.map_free = array_map_free,
|
|
.map_get_next_key = array_map_get_next_key,
|
|
.map_release_uref = array_map_free_timers,
|
|
.map_lookup_elem = array_map_lookup_elem,
|
|
.map_update_elem = array_map_update_elem,
|
|
.map_delete_elem = array_map_delete_elem,
|
|
.map_gen_lookup = array_map_gen_lookup,
|
|
.map_direct_value_addr = array_map_direct_value_addr,
|
|
.map_direct_value_meta = array_map_direct_value_meta,
|
|
.map_mmap = array_map_mmap,
|
|
.map_seq_show_elem = array_map_seq_show_elem,
|
|
.map_check_btf = array_map_check_btf,
|
|
.map_lookup_batch = generic_map_lookup_batch,
|
|
.map_update_batch = generic_map_update_batch,
|
|
.map_set_for_each_callback_args = map_set_for_each_callback_args,
|
|
.map_for_each_callback = bpf_for_each_array_elem,
|
|
.map_btf_id = &array_map_btf_ids[0],
|
|
.iter_seq_info = &iter_seq_info,
|
|
};
|
|
|
|
const struct bpf_map_ops percpu_array_map_ops = {
|
|
.map_meta_equal = bpf_map_meta_equal,
|
|
.map_alloc_check = array_map_alloc_check,
|
|
.map_alloc = array_map_alloc,
|
|
.map_free = array_map_free,
|
|
.map_get_next_key = array_map_get_next_key,
|
|
.map_lookup_elem = percpu_array_map_lookup_elem,
|
|
.map_update_elem = array_map_update_elem,
|
|
.map_delete_elem = array_map_delete_elem,
|
|
.map_lookup_percpu_elem = percpu_array_map_lookup_percpu_elem,
|
|
.map_seq_show_elem = percpu_array_map_seq_show_elem,
|
|
.map_check_btf = array_map_check_btf,
|
|
.map_lookup_batch = generic_map_lookup_batch,
|
|
.map_update_batch = generic_map_update_batch,
|
|
.map_set_for_each_callback_args = map_set_for_each_callback_args,
|
|
.map_for_each_callback = bpf_for_each_array_elem,
|
|
.map_btf_id = &array_map_btf_ids[0],
|
|
.iter_seq_info = &iter_seq_info,
|
|
};
|
|
|
|
static int fd_array_map_alloc_check(union bpf_attr *attr)
|
|
{
|
|
/* only file descriptors can be stored in this type of map */
|
|
if (attr->value_size != sizeof(u32))
|
|
return -EINVAL;
|
|
/* Program read-only/write-only not supported for special maps yet. */
|
|
if (attr->map_flags & (BPF_F_RDONLY_PROG | BPF_F_WRONLY_PROG))
|
|
return -EINVAL;
|
|
return array_map_alloc_check(attr);
|
|
}
|
|
|
|
static void fd_array_map_free(struct bpf_map *map)
|
|
{
|
|
struct bpf_array *array = container_of(map, struct bpf_array, map);
|
|
int i;
|
|
|
|
/* make sure it's empty */
|
|
for (i = 0; i < array->map.max_entries; i++)
|
|
BUG_ON(array->ptrs[i] != NULL);
|
|
|
|
bpf_map_area_free(array);
|
|
}
|
|
|
|
static void *fd_array_map_lookup_elem(struct bpf_map *map, void *key)
|
|
{
|
|
return ERR_PTR(-EOPNOTSUPP);
|
|
}
|
|
|
|
/* only called from syscall */
|
|
int bpf_fd_array_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
|
|
{
|
|
void **elem, *ptr;
|
|
int ret = 0;
|
|
|
|
if (!map->ops->map_fd_sys_lookup_elem)
|
|
return -ENOTSUPP;
|
|
|
|
rcu_read_lock();
|
|
elem = array_map_lookup_elem(map, key);
|
|
if (elem && (ptr = READ_ONCE(*elem)))
|
|
*value = map->ops->map_fd_sys_lookup_elem(ptr);
|
|
else
|
|
ret = -ENOENT;
|
|
rcu_read_unlock();
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* only called from syscall */
|
|
int bpf_fd_array_map_update_elem(struct bpf_map *map, struct file *map_file,
|
|
void *key, void *value, u64 map_flags)
|
|
{
|
|
struct bpf_array *array = container_of(map, struct bpf_array, map);
|
|
void *new_ptr, *old_ptr;
|
|
u32 index = *(u32 *)key, ufd;
|
|
|
|
if (map_flags != BPF_ANY)
|
|
return -EINVAL;
|
|
|
|
if (index >= array->map.max_entries)
|
|
return -E2BIG;
|
|
|
|
ufd = *(u32 *)value;
|
|
new_ptr = map->ops->map_fd_get_ptr(map, map_file, ufd);
|
|
if (IS_ERR(new_ptr))
|
|
return PTR_ERR(new_ptr);
|
|
|
|
if (map->ops->map_poke_run) {
|
|
mutex_lock(&array->aux->poke_mutex);
|
|
old_ptr = xchg(array->ptrs + index, new_ptr);
|
|
map->ops->map_poke_run(map, index, old_ptr, new_ptr);
|
|
mutex_unlock(&array->aux->poke_mutex);
|
|
} else {
|
|
old_ptr = xchg(array->ptrs + index, new_ptr);
|
|
}
|
|
|
|
if (old_ptr)
|
|
map->ops->map_fd_put_ptr(old_ptr);
|
|
return 0;
|
|
}
|
|
|
|
static int fd_array_map_delete_elem(struct bpf_map *map, void *key)
|
|
{
|
|
struct bpf_array *array = container_of(map, struct bpf_array, map);
|
|
void *old_ptr;
|
|
u32 index = *(u32 *)key;
|
|
|
|
if (index >= array->map.max_entries)
|
|
return -E2BIG;
|
|
|
|
if (map->ops->map_poke_run) {
|
|
mutex_lock(&array->aux->poke_mutex);
|
|
old_ptr = xchg(array->ptrs + index, NULL);
|
|
map->ops->map_poke_run(map, index, old_ptr, NULL);
|
|
mutex_unlock(&array->aux->poke_mutex);
|
|
} else {
|
|
old_ptr = xchg(array->ptrs + index, NULL);
|
|
}
|
|
|
|
if (old_ptr) {
|
|
map->ops->map_fd_put_ptr(old_ptr);
|
|
return 0;
|
|
} else {
|
|
return -ENOENT;
|
|
}
|
|
}
|
|
|
|
static void *prog_fd_array_get_ptr(struct bpf_map *map,
|
|
struct file *map_file, int fd)
|
|
{
|
|
struct bpf_prog *prog = bpf_prog_get(fd);
|
|
|
|
if (IS_ERR(prog))
|
|
return prog;
|
|
|
|
if (!bpf_prog_map_compatible(map, prog)) {
|
|
bpf_prog_put(prog);
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
return prog;
|
|
}
|
|
|
|
static void prog_fd_array_put_ptr(void *ptr)
|
|
{
|
|
bpf_prog_put(ptr);
|
|
}
|
|
|
|
static u32 prog_fd_array_sys_lookup_elem(void *ptr)
|
|
{
|
|
return ((struct bpf_prog *)ptr)->aux->id;
|
|
}
|
|
|
|
/* decrement refcnt of all bpf_progs that are stored in this map */
|
|
static void bpf_fd_array_map_clear(struct bpf_map *map)
|
|
{
|
|
struct bpf_array *array = container_of(map, struct bpf_array, map);
|
|
int i;
|
|
|
|
for (i = 0; i < array->map.max_entries; i++)
|
|
fd_array_map_delete_elem(map, &i);
|
|
}
|
|
|
|
static void prog_array_map_seq_show_elem(struct bpf_map *map, void *key,
|
|
struct seq_file *m)
|
|
{
|
|
void **elem, *ptr;
|
|
u32 prog_id;
|
|
|
|
rcu_read_lock();
|
|
|
|
elem = array_map_lookup_elem(map, key);
|
|
if (elem) {
|
|
ptr = READ_ONCE(*elem);
|
|
if (ptr) {
|
|
seq_printf(m, "%u: ", *(u32 *)key);
|
|
prog_id = prog_fd_array_sys_lookup_elem(ptr);
|
|
btf_type_seq_show(map->btf, map->btf_value_type_id,
|
|
&prog_id, m);
|
|
seq_puts(m, "\n");
|
|
}
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
struct prog_poke_elem {
|
|
struct list_head list;
|
|
struct bpf_prog_aux *aux;
|
|
};
|
|
|
|
static int prog_array_map_poke_track(struct bpf_map *map,
|
|
struct bpf_prog_aux *prog_aux)
|
|
{
|
|
struct prog_poke_elem *elem;
|
|
struct bpf_array_aux *aux;
|
|
int ret = 0;
|
|
|
|
aux = container_of(map, struct bpf_array, map)->aux;
|
|
mutex_lock(&aux->poke_mutex);
|
|
list_for_each_entry(elem, &aux->poke_progs, list) {
|
|
if (elem->aux == prog_aux)
|
|
goto out;
|
|
}
|
|
|
|
elem = kmalloc(sizeof(*elem), GFP_KERNEL);
|
|
if (!elem) {
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
INIT_LIST_HEAD(&elem->list);
|
|
/* We must track the program's aux info at this point in time
|
|
* since the program pointer itself may not be stable yet, see
|
|
* also comment in prog_array_map_poke_run().
|
|
*/
|
|
elem->aux = prog_aux;
|
|
|
|
list_add_tail(&elem->list, &aux->poke_progs);
|
|
out:
|
|
mutex_unlock(&aux->poke_mutex);
|
|
return ret;
|
|
}
|
|
|
|
static void prog_array_map_poke_untrack(struct bpf_map *map,
|
|
struct bpf_prog_aux *prog_aux)
|
|
{
|
|
struct prog_poke_elem *elem, *tmp;
|
|
struct bpf_array_aux *aux;
|
|
|
|
aux = container_of(map, struct bpf_array, map)->aux;
|
|
mutex_lock(&aux->poke_mutex);
|
|
list_for_each_entry_safe(elem, tmp, &aux->poke_progs, list) {
|
|
if (elem->aux == prog_aux) {
|
|
list_del_init(&elem->list);
|
|
kfree(elem);
|
|
break;
|
|
}
|
|
}
|
|
mutex_unlock(&aux->poke_mutex);
|
|
}
|
|
|
|
static void prog_array_map_poke_run(struct bpf_map *map, u32 key,
|
|
struct bpf_prog *old,
|
|
struct bpf_prog *new)
|
|
{
|
|
u8 *old_addr, *new_addr, *old_bypass_addr;
|
|
struct prog_poke_elem *elem;
|
|
struct bpf_array_aux *aux;
|
|
|
|
aux = container_of(map, struct bpf_array, map)->aux;
|
|
WARN_ON_ONCE(!mutex_is_locked(&aux->poke_mutex));
|
|
|
|
list_for_each_entry(elem, &aux->poke_progs, list) {
|
|
struct bpf_jit_poke_descriptor *poke;
|
|
int i, ret;
|
|
|
|
for (i = 0; i < elem->aux->size_poke_tab; i++) {
|
|
poke = &elem->aux->poke_tab[i];
|
|
|
|
/* Few things to be aware of:
|
|
*
|
|
* 1) We can only ever access aux in this context, but
|
|
* not aux->prog since it might not be stable yet and
|
|
* there could be danger of use after free otherwise.
|
|
* 2) Initially when we start tracking aux, the program
|
|
* is not JITed yet and also does not have a kallsyms
|
|
* entry. We skip these as poke->tailcall_target_stable
|
|
* is not active yet. The JIT will do the final fixup
|
|
* before setting it stable. The various
|
|
* poke->tailcall_target_stable are successively
|
|
* activated, so tail call updates can arrive from here
|
|
* while JIT is still finishing its final fixup for
|
|
* non-activated poke entries.
|
|
* 3) On program teardown, the program's kallsym entry gets
|
|
* removed out of RCU callback, but we can only untrack
|
|
* from sleepable context, therefore bpf_arch_text_poke()
|
|
* might not see that this is in BPF text section and
|
|
* bails out with -EINVAL. As these are unreachable since
|
|
* RCU grace period already passed, we simply skip them.
|
|
* 4) Also programs reaching refcount of zero while patching
|
|
* is in progress is okay since we're protected under
|
|
* poke_mutex and untrack the programs before the JIT
|
|
* buffer is freed. When we're still in the middle of
|
|
* patching and suddenly kallsyms entry of the program
|
|
* gets evicted, we just skip the rest which is fine due
|
|
* to point 3).
|
|
* 5) Any other error happening below from bpf_arch_text_poke()
|
|
* is a unexpected bug.
|
|
*/
|
|
if (!READ_ONCE(poke->tailcall_target_stable))
|
|
continue;
|
|
if (poke->reason != BPF_POKE_REASON_TAIL_CALL)
|
|
continue;
|
|
if (poke->tail_call.map != map ||
|
|
poke->tail_call.key != key)
|
|
continue;
|
|
|
|
old_bypass_addr = old ? NULL : poke->bypass_addr;
|
|
old_addr = old ? (u8 *)old->bpf_func + poke->adj_off : NULL;
|
|
new_addr = new ? (u8 *)new->bpf_func + poke->adj_off : NULL;
|
|
|
|
if (new) {
|
|
ret = bpf_arch_text_poke(poke->tailcall_target,
|
|
BPF_MOD_JUMP,
|
|
old_addr, new_addr);
|
|
BUG_ON(ret < 0 && ret != -EINVAL);
|
|
if (!old) {
|
|
ret = bpf_arch_text_poke(poke->tailcall_bypass,
|
|
BPF_MOD_JUMP,
|
|
poke->bypass_addr,
|
|
NULL);
|
|
BUG_ON(ret < 0 && ret != -EINVAL);
|
|
}
|
|
} else {
|
|
ret = bpf_arch_text_poke(poke->tailcall_bypass,
|
|
BPF_MOD_JUMP,
|
|
old_bypass_addr,
|
|
poke->bypass_addr);
|
|
BUG_ON(ret < 0 && ret != -EINVAL);
|
|
/* let other CPUs finish the execution of program
|
|
* so that it will not possible to expose them
|
|
* to invalid nop, stack unwind, nop state
|
|
*/
|
|
if (!ret)
|
|
synchronize_rcu();
|
|
ret = bpf_arch_text_poke(poke->tailcall_target,
|
|
BPF_MOD_JUMP,
|
|
old_addr, NULL);
|
|
BUG_ON(ret < 0 && ret != -EINVAL);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
static void prog_array_map_clear_deferred(struct work_struct *work)
|
|
{
|
|
struct bpf_map *map = container_of(work, struct bpf_array_aux,
|
|
work)->map;
|
|
bpf_fd_array_map_clear(map);
|
|
bpf_map_put(map);
|
|
}
|
|
|
|
static void prog_array_map_clear(struct bpf_map *map)
|
|
{
|
|
struct bpf_array_aux *aux = container_of(map, struct bpf_array,
|
|
map)->aux;
|
|
bpf_map_inc(map);
|
|
schedule_work(&aux->work);
|
|
}
|
|
|
|
static struct bpf_map *prog_array_map_alloc(union bpf_attr *attr)
|
|
{
|
|
struct bpf_array_aux *aux;
|
|
struct bpf_map *map;
|
|
|
|
aux = kzalloc(sizeof(*aux), GFP_KERNEL_ACCOUNT);
|
|
if (!aux)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
INIT_WORK(&aux->work, prog_array_map_clear_deferred);
|
|
INIT_LIST_HEAD(&aux->poke_progs);
|
|
mutex_init(&aux->poke_mutex);
|
|
|
|
map = array_map_alloc(attr);
|
|
if (IS_ERR(map)) {
|
|
kfree(aux);
|
|
return map;
|
|
}
|
|
|
|
container_of(map, struct bpf_array, map)->aux = aux;
|
|
aux->map = map;
|
|
|
|
return map;
|
|
}
|
|
|
|
static void prog_array_map_free(struct bpf_map *map)
|
|
{
|
|
struct prog_poke_elem *elem, *tmp;
|
|
struct bpf_array_aux *aux;
|
|
|
|
aux = container_of(map, struct bpf_array, map)->aux;
|
|
list_for_each_entry_safe(elem, tmp, &aux->poke_progs, list) {
|
|
list_del_init(&elem->list);
|
|
kfree(elem);
|
|
}
|
|
kfree(aux);
|
|
fd_array_map_free(map);
|
|
}
|
|
|
|
/* prog_array->aux->{type,jited} is a runtime binding.
|
|
* Doing static check alone in the verifier is not enough.
|
|
* Thus, prog_array_map cannot be used as an inner_map
|
|
* and map_meta_equal is not implemented.
|
|
*/
|
|
const struct bpf_map_ops prog_array_map_ops = {
|
|
.map_alloc_check = fd_array_map_alloc_check,
|
|
.map_alloc = prog_array_map_alloc,
|
|
.map_free = prog_array_map_free,
|
|
.map_poke_track = prog_array_map_poke_track,
|
|
.map_poke_untrack = prog_array_map_poke_untrack,
|
|
.map_poke_run = prog_array_map_poke_run,
|
|
.map_get_next_key = array_map_get_next_key,
|
|
.map_lookup_elem = fd_array_map_lookup_elem,
|
|
.map_delete_elem = fd_array_map_delete_elem,
|
|
.map_fd_get_ptr = prog_fd_array_get_ptr,
|
|
.map_fd_put_ptr = prog_fd_array_put_ptr,
|
|
.map_fd_sys_lookup_elem = prog_fd_array_sys_lookup_elem,
|
|
.map_release_uref = prog_array_map_clear,
|
|
.map_seq_show_elem = prog_array_map_seq_show_elem,
|
|
.map_btf_id = &array_map_btf_ids[0],
|
|
};
|
|
|
|
static struct bpf_event_entry *bpf_event_entry_gen(struct file *perf_file,
|
|
struct file *map_file)
|
|
{
|
|
struct bpf_event_entry *ee;
|
|
|
|
ee = kzalloc(sizeof(*ee), GFP_ATOMIC);
|
|
if (ee) {
|
|
ee->event = perf_file->private_data;
|
|
ee->perf_file = perf_file;
|
|
ee->map_file = map_file;
|
|
}
|
|
|
|
return ee;
|
|
}
|
|
|
|
static void __bpf_event_entry_free(struct rcu_head *rcu)
|
|
{
|
|
struct bpf_event_entry *ee;
|
|
|
|
ee = container_of(rcu, struct bpf_event_entry, rcu);
|
|
fput(ee->perf_file);
|
|
kfree(ee);
|
|
}
|
|
|
|
static void bpf_event_entry_free_rcu(struct bpf_event_entry *ee)
|
|
{
|
|
call_rcu(&ee->rcu, __bpf_event_entry_free);
|
|
}
|
|
|
|
static void *perf_event_fd_array_get_ptr(struct bpf_map *map,
|
|
struct file *map_file, int fd)
|
|
{
|
|
struct bpf_event_entry *ee;
|
|
struct perf_event *event;
|
|
struct file *perf_file;
|
|
u64 value;
|
|
|
|
perf_file = perf_event_get(fd);
|
|
if (IS_ERR(perf_file))
|
|
return perf_file;
|
|
|
|
ee = ERR_PTR(-EOPNOTSUPP);
|
|
event = perf_file->private_data;
|
|
if (perf_event_read_local(event, &value, NULL, NULL) == -EOPNOTSUPP)
|
|
goto err_out;
|
|
|
|
ee = bpf_event_entry_gen(perf_file, map_file);
|
|
if (ee)
|
|
return ee;
|
|
ee = ERR_PTR(-ENOMEM);
|
|
err_out:
|
|
fput(perf_file);
|
|
return ee;
|
|
}
|
|
|
|
static void perf_event_fd_array_put_ptr(void *ptr)
|
|
{
|
|
bpf_event_entry_free_rcu(ptr);
|
|
}
|
|
|
|
static void perf_event_fd_array_release(struct bpf_map *map,
|
|
struct file *map_file)
|
|
{
|
|
struct bpf_array *array = container_of(map, struct bpf_array, map);
|
|
struct bpf_event_entry *ee;
|
|
int i;
|
|
|
|
if (map->map_flags & BPF_F_PRESERVE_ELEMS)
|
|
return;
|
|
|
|
rcu_read_lock();
|
|
for (i = 0; i < array->map.max_entries; i++) {
|
|
ee = READ_ONCE(array->ptrs[i]);
|
|
if (ee && ee->map_file == map_file)
|
|
fd_array_map_delete_elem(map, &i);
|
|
}
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
static void perf_event_fd_array_map_free(struct bpf_map *map)
|
|
{
|
|
if (map->map_flags & BPF_F_PRESERVE_ELEMS)
|
|
bpf_fd_array_map_clear(map);
|
|
fd_array_map_free(map);
|
|
}
|
|
|
|
const struct bpf_map_ops perf_event_array_map_ops = {
|
|
.map_meta_equal = bpf_map_meta_equal,
|
|
.map_alloc_check = fd_array_map_alloc_check,
|
|
.map_alloc = array_map_alloc,
|
|
.map_free = perf_event_fd_array_map_free,
|
|
.map_get_next_key = array_map_get_next_key,
|
|
.map_lookup_elem = fd_array_map_lookup_elem,
|
|
.map_delete_elem = fd_array_map_delete_elem,
|
|
.map_fd_get_ptr = perf_event_fd_array_get_ptr,
|
|
.map_fd_put_ptr = perf_event_fd_array_put_ptr,
|
|
.map_release = perf_event_fd_array_release,
|
|
.map_check_btf = map_check_no_btf,
|
|
.map_btf_id = &array_map_btf_ids[0],
|
|
};
|
|
|
|
#ifdef CONFIG_CGROUPS
|
|
static void *cgroup_fd_array_get_ptr(struct bpf_map *map,
|
|
struct file *map_file /* not used */,
|
|
int fd)
|
|
{
|
|
return cgroup_get_from_fd(fd);
|
|
}
|
|
|
|
static void cgroup_fd_array_put_ptr(void *ptr)
|
|
{
|
|
/* cgroup_put free cgrp after a rcu grace period */
|
|
cgroup_put(ptr);
|
|
}
|
|
|
|
static void cgroup_fd_array_free(struct bpf_map *map)
|
|
{
|
|
bpf_fd_array_map_clear(map);
|
|
fd_array_map_free(map);
|
|
}
|
|
|
|
const struct bpf_map_ops cgroup_array_map_ops = {
|
|
.map_meta_equal = bpf_map_meta_equal,
|
|
.map_alloc_check = fd_array_map_alloc_check,
|
|
.map_alloc = array_map_alloc,
|
|
.map_free = cgroup_fd_array_free,
|
|
.map_get_next_key = array_map_get_next_key,
|
|
.map_lookup_elem = fd_array_map_lookup_elem,
|
|
.map_delete_elem = fd_array_map_delete_elem,
|
|
.map_fd_get_ptr = cgroup_fd_array_get_ptr,
|
|
.map_fd_put_ptr = cgroup_fd_array_put_ptr,
|
|
.map_check_btf = map_check_no_btf,
|
|
.map_btf_id = &array_map_btf_ids[0],
|
|
};
|
|
#endif
|
|
|
|
static struct bpf_map *array_of_map_alloc(union bpf_attr *attr)
|
|
{
|
|
struct bpf_map *map, *inner_map_meta;
|
|
|
|
inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
|
|
if (IS_ERR(inner_map_meta))
|
|
return inner_map_meta;
|
|
|
|
map = array_map_alloc(attr);
|
|
if (IS_ERR(map)) {
|
|
bpf_map_meta_free(inner_map_meta);
|
|
return map;
|
|
}
|
|
|
|
map->inner_map_meta = inner_map_meta;
|
|
|
|
return map;
|
|
}
|
|
|
|
static void array_of_map_free(struct bpf_map *map)
|
|
{
|
|
/* map->inner_map_meta is only accessed by syscall which
|
|
* is protected by fdget/fdput.
|
|
*/
|
|
bpf_map_meta_free(map->inner_map_meta);
|
|
bpf_fd_array_map_clear(map);
|
|
fd_array_map_free(map);
|
|
}
|
|
|
|
static void *array_of_map_lookup_elem(struct bpf_map *map, void *key)
|
|
{
|
|
struct bpf_map **inner_map = array_map_lookup_elem(map, key);
|
|
|
|
if (!inner_map)
|
|
return NULL;
|
|
|
|
return READ_ONCE(*inner_map);
|
|
}
|
|
|
|
static int array_of_map_gen_lookup(struct bpf_map *map,
|
|
struct bpf_insn *insn_buf)
|
|
{
|
|
struct bpf_array *array = container_of(map, struct bpf_array, map);
|
|
u32 elem_size = array->elem_size;
|
|
struct bpf_insn *insn = insn_buf;
|
|
const int ret = BPF_REG_0;
|
|
const int map_ptr = BPF_REG_1;
|
|
const int index = BPF_REG_2;
|
|
|
|
*insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
|
|
*insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
|
|
if (!map->bypass_spec_v1) {
|
|
*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 6);
|
|
*insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
|
|
} else {
|
|
*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 5);
|
|
}
|
|
if (is_power_of_2(elem_size))
|
|
*insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(elem_size));
|
|
else
|
|
*insn++ = BPF_ALU64_IMM(BPF_MUL, ret, elem_size);
|
|
*insn++ = BPF_ALU64_REG(BPF_ADD, ret, map_ptr);
|
|
*insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0);
|
|
*insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1);
|
|
*insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
|
|
*insn++ = BPF_MOV64_IMM(ret, 0);
|
|
|
|
return insn - insn_buf;
|
|
}
|
|
|
|
const struct bpf_map_ops array_of_maps_map_ops = {
|
|
.map_alloc_check = fd_array_map_alloc_check,
|
|
.map_alloc = array_of_map_alloc,
|
|
.map_free = array_of_map_free,
|
|
.map_get_next_key = array_map_get_next_key,
|
|
.map_lookup_elem = array_of_map_lookup_elem,
|
|
.map_delete_elem = fd_array_map_delete_elem,
|
|
.map_fd_get_ptr = bpf_map_fd_get_ptr,
|
|
.map_fd_put_ptr = bpf_map_fd_put_ptr,
|
|
.map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
|
|
.map_gen_lookup = array_of_map_gen_lookup,
|
|
.map_lookup_batch = generic_map_lookup_batch,
|
|
.map_update_batch = generic_map_update_batch,
|
|
.map_check_btf = map_check_no_btf,
|
|
.map_btf_id = &array_map_btf_ids[0],
|
|
};
|