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-rw-r--r--kernel/bpf/queue_stack_maps.c299
1 files changed, 299 insertions, 0 deletions
diff --git a/kernel/bpf/queue_stack_maps.c b/kernel/bpf/queue_stack_maps.c
new file mode 100644
index 0000000000..d869f51ea9
--- /dev/null
+++ b/kernel/bpf/queue_stack_maps.c
@@ -0,0 +1,299 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * queue_stack_maps.c: BPF queue and stack maps
+ *
+ * Copyright (c) 2018 Politecnico di Torino
+ */
+#include <linux/bpf.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/btf_ids.h>
+#include "percpu_freelist.h"
+
+#define QUEUE_STACK_CREATE_FLAG_MASK \
+ (BPF_F_NUMA_NODE | BPF_F_ACCESS_MASK)
+
+struct bpf_queue_stack {
+ struct bpf_map map;
+ raw_spinlock_t lock;
+ u32 head, tail;
+ u32 size; /* max_entries + 1 */
+
+ char elements[] __aligned(8);
+};
+
+static struct bpf_queue_stack *bpf_queue_stack(struct bpf_map *map)
+{
+ return container_of(map, struct bpf_queue_stack, map);
+}
+
+static bool queue_stack_map_is_empty(struct bpf_queue_stack *qs)
+{
+ return qs->head == qs->tail;
+}
+
+static bool queue_stack_map_is_full(struct bpf_queue_stack *qs)
+{
+ u32 head = qs->head + 1;
+
+ if (unlikely(head >= qs->size))
+ head = 0;
+
+ return head == qs->tail;
+}
+
+/* Called from syscall */
+static int queue_stack_map_alloc_check(union bpf_attr *attr)
+{
+ /* check sanity of attributes */
+ if (attr->max_entries == 0 || attr->key_size != 0 ||
+ attr->value_size == 0 ||
+ attr->map_flags & ~QUEUE_STACK_CREATE_FLAG_MASK ||
+ !bpf_map_flags_access_ok(attr->map_flags))
+ return -EINVAL;
+
+ if (attr->value_size > KMALLOC_MAX_SIZE)
+ /* if value_size is bigger, the user space won't be able to
+ * access the elements.
+ */
+ return -E2BIG;
+
+ return 0;
+}
+
+static struct bpf_map *queue_stack_map_alloc(union bpf_attr *attr)
+{
+ int numa_node = bpf_map_attr_numa_node(attr);
+ struct bpf_queue_stack *qs;
+ u64 size, queue_size;
+
+ size = (u64) attr->max_entries + 1;
+ queue_size = sizeof(*qs) + size * attr->value_size;
+
+ qs = bpf_map_area_alloc(queue_size, numa_node);
+ if (!qs)
+ return ERR_PTR(-ENOMEM);
+
+ bpf_map_init_from_attr(&qs->map, attr);
+
+ qs->size = size;
+
+ raw_spin_lock_init(&qs->lock);
+
+ return &qs->map;
+}
+
+/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
+static void queue_stack_map_free(struct bpf_map *map)
+{
+ struct bpf_queue_stack *qs = bpf_queue_stack(map);
+
+ bpf_map_area_free(qs);
+}
+
+static long __queue_map_get(struct bpf_map *map, void *value, bool delete)
+{
+ struct bpf_queue_stack *qs = bpf_queue_stack(map);
+ unsigned long flags;
+ int err = 0;
+ void *ptr;
+
+ if (in_nmi()) {
+ if (!raw_spin_trylock_irqsave(&qs->lock, flags))
+ return -EBUSY;
+ } else {
+ raw_spin_lock_irqsave(&qs->lock, flags);
+ }
+
+ if (queue_stack_map_is_empty(qs)) {
+ memset(value, 0, qs->map.value_size);
+ err = -ENOENT;
+ goto out;
+ }
+
+ ptr = &qs->elements[qs->tail * qs->map.value_size];
+ memcpy(value, ptr, qs->map.value_size);
+
+ if (delete) {
+ if (unlikely(++qs->tail >= qs->size))
+ qs->tail = 0;
+ }
+
+out:
+ raw_spin_unlock_irqrestore(&qs->lock, flags);
+ return err;
+}
+
+
+static long __stack_map_get(struct bpf_map *map, void *value, bool delete)
+{
+ struct bpf_queue_stack *qs = bpf_queue_stack(map);
+ unsigned long flags;
+ int err = 0;
+ void *ptr;
+ u32 index;
+
+ if (in_nmi()) {
+ if (!raw_spin_trylock_irqsave(&qs->lock, flags))
+ return -EBUSY;
+ } else {
+ raw_spin_lock_irqsave(&qs->lock, flags);
+ }
+
+ if (queue_stack_map_is_empty(qs)) {
+ memset(value, 0, qs->map.value_size);
+ err = -ENOENT;
+ goto out;
+ }
+
+ index = qs->head - 1;
+ if (unlikely(index >= qs->size))
+ index = qs->size - 1;
+
+ ptr = &qs->elements[index * qs->map.value_size];
+ memcpy(value, ptr, qs->map.value_size);
+
+ if (delete)
+ qs->head = index;
+
+out:
+ raw_spin_unlock_irqrestore(&qs->lock, flags);
+ return err;
+}
+
+/* Called from syscall or from eBPF program */
+static long queue_map_peek_elem(struct bpf_map *map, void *value)
+{
+ return __queue_map_get(map, value, false);
+}
+
+/* Called from syscall or from eBPF program */
+static long stack_map_peek_elem(struct bpf_map *map, void *value)
+{
+ return __stack_map_get(map, value, false);
+}
+
+/* Called from syscall or from eBPF program */
+static long queue_map_pop_elem(struct bpf_map *map, void *value)
+{
+ return __queue_map_get(map, value, true);
+}
+
+/* Called from syscall or from eBPF program */
+static long stack_map_pop_elem(struct bpf_map *map, void *value)
+{
+ return __stack_map_get(map, value, true);
+}
+
+/* Called from syscall or from eBPF program */
+static long queue_stack_map_push_elem(struct bpf_map *map, void *value,
+ u64 flags)
+{
+ struct bpf_queue_stack *qs = bpf_queue_stack(map);
+ unsigned long irq_flags;
+ int err = 0;
+ void *dst;
+
+ /* BPF_EXIST is used to force making room for a new element in case the
+ * map is full
+ */
+ bool replace = (flags & BPF_EXIST);
+
+ /* Check supported flags for queue and stack maps */
+ if (flags & BPF_NOEXIST || flags > BPF_EXIST)
+ return -EINVAL;
+
+ if (in_nmi()) {
+ if (!raw_spin_trylock_irqsave(&qs->lock, irq_flags))
+ return -EBUSY;
+ } else {
+ raw_spin_lock_irqsave(&qs->lock, irq_flags);
+ }
+
+ if (queue_stack_map_is_full(qs)) {
+ if (!replace) {
+ err = -E2BIG;
+ goto out;
+ }
+ /* advance tail pointer to overwrite oldest element */
+ if (unlikely(++qs->tail >= qs->size))
+ qs->tail = 0;
+ }
+
+ dst = &qs->elements[qs->head * qs->map.value_size];
+ memcpy(dst, value, qs->map.value_size);
+
+ if (unlikely(++qs->head >= qs->size))
+ qs->head = 0;
+
+out:
+ raw_spin_unlock_irqrestore(&qs->lock, irq_flags);
+ return err;
+}
+
+/* Called from syscall or from eBPF program */
+static void *queue_stack_map_lookup_elem(struct bpf_map *map, void *key)
+{
+ return NULL;
+}
+
+/* Called from syscall or from eBPF program */
+static long queue_stack_map_update_elem(struct bpf_map *map, void *key,
+ void *value, u64 flags)
+{
+ return -EINVAL;
+}
+
+/* Called from syscall or from eBPF program */
+static long queue_stack_map_delete_elem(struct bpf_map *map, void *key)
+{
+ return -EINVAL;
+}
+
+/* Called from syscall */
+static int queue_stack_map_get_next_key(struct bpf_map *map, void *key,
+ void *next_key)
+{
+ return -EINVAL;
+}
+
+static u64 queue_stack_map_mem_usage(const struct bpf_map *map)
+{
+ u64 usage = sizeof(struct bpf_queue_stack);
+
+ usage += ((u64)map->max_entries + 1) * map->value_size;
+ return usage;
+}
+
+BTF_ID_LIST_SINGLE(queue_map_btf_ids, struct, bpf_queue_stack)
+const struct bpf_map_ops queue_map_ops = {
+ .map_meta_equal = bpf_map_meta_equal,
+ .map_alloc_check = queue_stack_map_alloc_check,
+ .map_alloc = queue_stack_map_alloc,
+ .map_free = queue_stack_map_free,
+ .map_lookup_elem = queue_stack_map_lookup_elem,
+ .map_update_elem = queue_stack_map_update_elem,
+ .map_delete_elem = queue_stack_map_delete_elem,
+ .map_push_elem = queue_stack_map_push_elem,
+ .map_pop_elem = queue_map_pop_elem,
+ .map_peek_elem = queue_map_peek_elem,
+ .map_get_next_key = queue_stack_map_get_next_key,
+ .map_mem_usage = queue_stack_map_mem_usage,
+ .map_btf_id = &queue_map_btf_ids[0],
+};
+
+const struct bpf_map_ops stack_map_ops = {
+ .map_meta_equal = bpf_map_meta_equal,
+ .map_alloc_check = queue_stack_map_alloc_check,
+ .map_alloc = queue_stack_map_alloc,
+ .map_free = queue_stack_map_free,
+ .map_lookup_elem = queue_stack_map_lookup_elem,
+ .map_update_elem = queue_stack_map_update_elem,
+ .map_delete_elem = queue_stack_map_delete_elem,
+ .map_push_elem = queue_stack_map_push_elem,
+ .map_pop_elem = stack_map_pop_elem,
+ .map_peek_elem = stack_map_peek_elem,
+ .map_get_next_key = queue_stack_map_get_next_key,
+ .map_mem_usage = queue_stack_map_mem_usage,
+ .map_btf_id = &queue_map_btf_ids[0],
+};
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-12 12:52:04 +0000