/* Called from syscall */
static struct bpf_map *stack_map_alloc(union bpf_attr *attr)
{
u32 value_size = attr->value_size;
struct bpf_stack_map *smap;
u64 cost, n_buckets;
int err;
if (!capable(CAP_SYS_ADMIN))
return ERR_PTR(-EPERM);
if (attr->map_flags & ~STACK_CREATE_FLAG_MASK)
return ERR_PTR(-EINVAL);
/* check sanity of attributes */
if (attr->max_entries == 0 || attr->key_size != 4 ||
value_size < 8 || value_size % 8 ||
value_size / 8 > sysctl_perf_event_max_stack)
return ERR_PTR(-EINVAL);
/* hash table size must be power of 2 */
n_buckets = roundup_pow_of_two(attr->max_entries);
cost = n_buckets * sizeof(struct stack_map_bucket *) + sizeof(*smap);
if (cost >= U32_MAX - PAGE_SIZE)
return ERR_PTR(-E2BIG);
smap = bpf_map_area_alloc(cost, bpf_map_attr_numa_node(attr));
if (!smap)
return ERR_PTR(-ENOMEM);
err = -E2BIG;
cost += n_buckets * (value_size + sizeof(struct stack_map_bucket));
if (cost >= U32_MAX - PAGE_SIZE)
goto free_smap;
bpf_map_init_from_attr(&smap->map, attr);
smap->map.value_size = value_size;
smap->n_buckets = n_buckets;
smap->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;
err = bpf_map_precharge_memlock(smap->map.pages);
if (err)
goto free_smap;
err = get_callchain_buffers(sysctl_perf_event_max_stack);
if (err)
goto free_smap;
err = prealloc_elems_and_freelist(smap);
if (err)
goto put_buffers;
return &smap->map;
put_buffers:
put_callchain_buffers();
free_smap:
bpf_map_area_free(smap);
return ERR_PTR(err);
}
/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
static void stack_map_free(struct bpf_map *map)
{
struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
/* wait for bpf programs to complete before freeing stack map */
synchronize_rcu();
bpf_map_area_free(smap->elems);
pcpu_freelist_destroy(&smap->freelist);
bpf_map_area_free(smap);
put_callchain_buffers();
}
/* Called from syscall */
static struct bpf_map *stack_map_alloc(union bpf_attr *attr)
{
u32 value_size = attr->value_size;
struct bpf_stack_map *smap;
u64 cost, n_buckets;
int err;
if (!capable(CAP_SYS_ADMIN))
return ERR_PTR(-EPERM);
if (attr->map_flags)
return ERR_PTR(-EINVAL);
/* check sanity of attributes */
if (attr->max_entries == 0 || attr->key_size != 4 ||
value_size < 8 || value_size % 8 ||
value_size / 8 > PERF_MAX_STACK_DEPTH)
return ERR_PTR(-EINVAL);
/* hash table size must be power of 2 */
n_buckets = roundup_pow_of_two(attr->max_entries);
cost = n_buckets * sizeof(struct stack_map_bucket *) + sizeof(*smap);
if (cost >= U32_MAX - PAGE_SIZE)
return ERR_PTR(-E2BIG);
smap = kzalloc(cost, GFP_USER | __GFP_NOWARN);
if (!smap) {
smap = vzalloc(cost);
if (!smap)
return ERR_PTR(-ENOMEM);
}
err = -E2BIG;
cost += n_buckets * (value_size + sizeof(struct stack_map_bucket));
if (cost >= U32_MAX - PAGE_SIZE)
goto free_smap;
smap->map.map_type = attr->map_type;
smap->map.key_size = attr->key_size;
smap->map.value_size = value_size;
smap->map.max_entries = attr->max_entries;
smap->n_buckets = n_buckets;
smap->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;
err = bpf_map_precharge_memlock(smap->map.pages);
if (err)
goto free_smap;
err = get_callchain_buffers();
if (err)
goto free_smap;
err = prealloc_elems_and_freelist(smap);
if (err)
goto put_buffers;
return &smap->map;
put_buffers:
put_callchain_buffers();
free_smap:
kvfree(smap);
return ERR_PTR(err);
}