#include <linux/filter.h>
#include <linux/perf_event.h>
+static void bpf_array_free_percpu(struct bpf_array *array)
+{
+ int i;
+
+ for (i = 0; i < array->map.max_entries; i++)
+ free_percpu(array->pptrs[i]);
+}
+
+static int bpf_array_alloc_percpu(struct bpf_array *array)
+{
+ void __percpu *ptr;
+ int i;
+
+ for (i = 0; i < array->map.max_entries; i++) {
+ ptr = __alloc_percpu_gfp(array->elem_size, 8,
+ GFP_USER | __GFP_NOWARN);
+ if (!ptr) {
+ bpf_array_free_percpu(array);
+ return -ENOMEM;
+ }
+ array->pptrs[i] = ptr;
+ }
+
+ return 0;
+}
+
/* Called from syscall */
static struct bpf_map *array_map_alloc(union bpf_attr *attr)
{
+ bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
struct bpf_array *array;
- u32 elem_size, array_size;
+ u64 array_size;
+ u32 elem_size;
/* check sanity of attributes */
if (attr->max_entries == 0 || attr->key_size != 4 ||
- attr->value_size == 0)
+ attr->value_size == 0 || attr->map_flags)
return ERR_PTR(-EINVAL);
if (attr->value_size >= 1 << (KMALLOC_SHIFT_MAX - 1))
elem_size = round_up(attr->value_size, 8);
- /* check round_up into zero and u32 overflow */
- if (elem_size == 0 ||
- attr->max_entries > (U32_MAX - PAGE_SIZE - sizeof(*array)) / elem_size)
+ array_size = sizeof(*array);
+ if (percpu)
+ array_size += (u64) attr->max_entries * sizeof(void *);
+ else
+ array_size += (u64) attr->max_entries * elem_size;
+
+ /* make sure there is no u32 overflow later in round_up() */
+ if (array_size >= U32_MAX - PAGE_SIZE)
return ERR_PTR(-ENOMEM);
- array_size = sizeof(*array) + attr->max_entries * elem_size;
/* allocate all map elements and zero-initialize them */
array = kzalloc(array_size, GFP_USER | __GFP_NOWARN);
}
/* copy mandatory map attributes */
+ array->map.map_type = attr->map_type;
array->map.key_size = attr->key_size;
array->map.value_size = attr->value_size;
array->map.max_entries = attr->max_entries;
- array->map.pages = round_up(array_size, PAGE_SIZE) >> PAGE_SHIFT;
array->elem_size = elem_size;
+ if (!percpu)
+ goto out;
+
+ array_size += (u64) attr->max_entries * elem_size * num_possible_cpus();
+
+ if (array_size >= U32_MAX - PAGE_SIZE ||
+ elem_size > PCPU_MIN_UNIT_SIZE || bpf_array_alloc_percpu(array)) {
+ kvfree(array);
+ return ERR_PTR(-ENOMEM);
+ }
+out:
+ array->map.pages = round_up(array_size, PAGE_SIZE) >> PAGE_SHIFT;
+
return &array->map;
}
struct bpf_array *array = container_of(map, struct bpf_array, map);
u32 index = *(u32 *)key;
- if (index >= array->map.max_entries)
+ if (unlikely(index >= array->map.max_entries))
return NULL;
return array->value + array->elem_size * index;
}
+/* Called from eBPF program */
+static void *percpu_array_map_lookup_elem(struct bpf_map *map, void *key)
+{
+ struct bpf_array *array = container_of(map, struct bpf_array, map);
+ u32 index = *(u32 *)key;
+
+ if (unlikely(index >= array->map.max_entries))
+ return NULL;
+
+ return this_cpu_ptr(array->pptrs[index]);
+}
+
+int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value)
+{
+ struct bpf_array *array = container_of(map, struct bpf_array, map);
+ u32 index = *(u32 *)key;
+ void __percpu *pptr;
+ int cpu, off = 0;
+ u32 size;
+
+ if (unlikely(index >= array->map.max_entries))
+ return -ENOENT;
+
+ /* per_cpu areas are zero-filled and bpf programs can only
+ * access 'value_size' of them, so copying rounded areas
+ * will not leak any kernel data
+ */
+ size = round_up(map->value_size, 8);
+ rcu_read_lock();
+ pptr = array->pptrs[index];
+ for_each_possible_cpu(cpu) {
+ bpf_long_memcpy(value + off, per_cpu_ptr(pptr, cpu), size);
+ off += size;
+ }
+ rcu_read_unlock();
+ return 0;
+}
+
/* Called from syscall */
static int array_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
u32 index = *(u32 *)key;
- if (map_flags > BPF_EXIST)
+ if (unlikely(map_flags > BPF_EXIST))
/* unknown flags */
return -EINVAL;
- if (index >= array->map.max_entries)
+ if (unlikely(index >= array->map.max_entries))
/* all elements were pre-allocated, cannot insert a new one */
return -E2BIG;
- if (map_flags == BPF_NOEXIST)
+ if (unlikely(map_flags == BPF_NOEXIST))
/* all elements already exist */
return -EEXIST;
- memcpy(array->value + array->elem_size * index, value, map->value_size);
+ if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
+ memcpy(this_cpu_ptr(array->pptrs[index]),
+ value, map->value_size);
+ else
+ memcpy(array->value + array->elem_size * index,
+ value, map->value_size);
+ return 0;
+}
+
+int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
+ u64 map_flags)
+{
+ struct bpf_array *array = container_of(map, struct bpf_array, map);
+ u32 index = *(u32 *)key;
+ void __percpu *pptr;
+ int cpu, off = 0;
+ u32 size;
+
+ if (unlikely(map_flags > BPF_EXIST))
+ /* unknown flags */
+ return -EINVAL;
+
+ if (unlikely(index >= array->map.max_entries))
+ /* all elements were pre-allocated, cannot insert a new one */
+ return -E2BIG;
+
+ if (unlikely(map_flags == BPF_NOEXIST))
+ /* all elements already exist */
+ return -EEXIST;
+
+ /* the user space will provide round_up(value_size, 8) bytes that
+ * will be copied into per-cpu area. bpf programs can only access
+ * value_size of it. During lookup the same extra bytes will be
+ * returned or zeros which were zero-filled by percpu_alloc,
+ * so no kernel data leaks possible
+ */
+ size = round_up(map->value_size, 8);
+ rcu_read_lock();
+ pptr = array->pptrs[index];
+ for_each_possible_cpu(cpu) {
+ bpf_long_memcpy(per_cpu_ptr(pptr, cpu), value + off, size);
+ off += size;
+ }
+ rcu_read_unlock();
return 0;
}
*/
synchronize_rcu();
+ if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
+ bpf_array_free_percpu(array);
+
kvfree(array);
}
.type = BPF_MAP_TYPE_ARRAY,
};
+static const struct bpf_map_ops percpu_array_ops = {
+ .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,
+};
+
+static struct bpf_map_type_list percpu_array_type __read_mostly = {
+ .ops = &percpu_array_ops,
+ .type = BPF_MAP_TYPE_PERCPU_ARRAY,
+};
+
static int __init register_array_map(void)
{
bpf_register_map_type(&array_type);
+ bpf_register_map_type(&percpu_array_type);
return 0;
}
late_initcall(register_array_map);
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