forked from luck/tmp_suning_uos_patched
bpf: Make the bpf_prog_array_map more generic
All the map backends are of generic nature. In order to avoid adding much special code into the eBPF core, rewrite part of the bpf_prog_array map code and make it more generic. So the new perf_event_array map type can reuse most of code with bpf_prog_array map and add fewer lines of special code. Signed-off-by: Wang Nan <wangnan0@huawei.com> Signed-off-by: Kaixu Xia <xiakaixu@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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parent
ffe8690c85
commit
2a36f0b92e
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@ -246,7 +246,7 @@ static void emit_prologue(u8 **pprog)
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* goto out;
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* if (++tail_call_cnt > MAX_TAIL_CALL_CNT)
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* goto out;
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* prog = array->prog[index];
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* prog = array->ptrs[index];
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* if (prog == NULL)
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* goto out;
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* goto *(prog->bpf_func + prologue_size);
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@ -284,9 +284,9 @@ static void emit_bpf_tail_call(u8 **pprog)
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EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */
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EMIT2_off32(0x89, 0x85, -STACKSIZE + 36); /* mov dword ptr [rbp - 516], eax */
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/* prog = array->prog[index]; */
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/* prog = array->ptrs[index]; */
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EMIT4_off32(0x48, 0x8D, 0x84, 0xD6, /* lea rax, [rsi + rdx * 8 + offsetof(...)] */
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offsetof(struct bpf_array, prog));
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offsetof(struct bpf_array, ptrs));
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EMIT3(0x48, 0x8B, 0x00); /* mov rax, qword ptr [rax] */
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/* if (prog == NULL)
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@ -24,6 +24,10 @@ struct bpf_map_ops {
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void *(*map_lookup_elem)(struct bpf_map *map, void *key);
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int (*map_update_elem)(struct bpf_map *map, void *key, void *value, u64 flags);
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int (*map_delete_elem)(struct bpf_map *map, void *key);
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/* funcs called by prog_array and perf_event_array map */
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void *(*map_fd_get_ptr) (struct bpf_map *map, int fd);
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void (*map_fd_put_ptr) (void *ptr);
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};
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struct bpf_map {
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@ -142,13 +146,13 @@ struct bpf_array {
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bool owner_jited;
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union {
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char value[0] __aligned(8);
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struct bpf_prog *prog[0] __aligned(8);
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void *ptrs[0] __aligned(8);
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};
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};
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#define MAX_TAIL_CALL_CNT 32
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u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5);
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void bpf_prog_array_map_clear(struct bpf_map *map);
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void bpf_fd_array_map_clear(struct bpf_map *map);
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bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp);
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const struct bpf_func_proto *bpf_get_trace_printk_proto(void);
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@ -150,15 +150,15 @@ static int __init register_array_map(void)
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}
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late_initcall(register_array_map);
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static struct bpf_map *prog_array_map_alloc(union bpf_attr *attr)
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static struct bpf_map *fd_array_map_alloc(union bpf_attr *attr)
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{
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/* only bpf_prog file descriptors can be stored in prog_array map */
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/* only file descriptors can be stored in this type of map */
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if (attr->value_size != sizeof(u32))
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return ERR_PTR(-EINVAL);
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return array_map_alloc(attr);
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}
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static void prog_array_map_free(struct bpf_map *map)
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static void fd_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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@ -167,21 +167,21 @@ static void prog_array_map_free(struct bpf_map *map)
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/* make sure it's empty */
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for (i = 0; i < array->map.max_entries; i++)
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BUG_ON(array->prog[i] != NULL);
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BUG_ON(array->ptrs[i] != NULL);
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kvfree(array);
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}
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static void *prog_array_map_lookup_elem(struct bpf_map *map, void *key)
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static void *fd_array_map_lookup_elem(struct bpf_map *map, void *key)
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{
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return NULL;
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}
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/* only called from syscall */
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static int prog_array_map_update_elem(struct bpf_map *map, void *key,
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static int fd_array_map_update_elem(struct bpf_map *map, void *key,
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void *value, 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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struct bpf_prog *prog, *old_prog;
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void *new_ptr, *old_ptr;
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u32 index = *(u32 *)key, ufd;
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if (map_flags != BPF_ANY)
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@ -191,57 +191,75 @@ static int prog_array_map_update_elem(struct bpf_map *map, void *key,
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return -E2BIG;
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ufd = *(u32 *)value;
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prog = bpf_prog_get(ufd);
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if (IS_ERR(prog))
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return PTR_ERR(prog);
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new_ptr = map->ops->map_fd_get_ptr(map, ufd);
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if (IS_ERR(new_ptr))
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return PTR_ERR(new_ptr);
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if (!bpf_prog_array_compatible(array, prog)) {
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bpf_prog_put(prog);
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return -EINVAL;
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}
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old_prog = xchg(array->prog + index, prog);
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if (old_prog)
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bpf_prog_put_rcu(old_prog);
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old_ptr = xchg(array->ptrs + index, new_ptr);
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if (old_ptr)
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map->ops->map_fd_put_ptr(old_ptr);
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return 0;
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}
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static int prog_array_map_delete_elem(struct bpf_map *map, void *key)
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static int fd_array_map_delete_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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struct bpf_prog *old_prog;
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void *old_ptr;
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u32 index = *(u32 *)key;
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if (index >= array->map.max_entries)
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return -E2BIG;
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old_prog = xchg(array->prog + index, NULL);
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if (old_prog) {
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bpf_prog_put_rcu(old_prog);
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old_ptr = xchg(array->ptrs + index, NULL);
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if (old_ptr) {
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map->ops->map_fd_put_ptr(old_ptr);
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return 0;
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} else {
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return -ENOENT;
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}
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}
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static void *prog_fd_array_get_ptr(struct bpf_map *map, int fd)
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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_prog *prog = bpf_prog_get(fd);
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if (IS_ERR(prog))
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return prog;
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if (!bpf_prog_array_compatible(array, prog)) {
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bpf_prog_put(prog);
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return ERR_PTR(-EINVAL);
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}
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return prog;
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}
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static void prog_fd_array_put_ptr(void *ptr)
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{
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struct bpf_prog *prog = ptr;
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bpf_prog_put_rcu(prog);
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}
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/* decrement refcnt of all bpf_progs that are stored in this map */
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void bpf_prog_array_map_clear(struct bpf_map *map)
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void bpf_fd_array_map_clear(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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for (i = 0; i < array->map.max_entries; i++)
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prog_array_map_delete_elem(map, &i);
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fd_array_map_delete_elem(map, &i);
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}
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static const struct bpf_map_ops prog_array_ops = {
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.map_alloc = prog_array_map_alloc,
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.map_free = prog_array_map_free,
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.map_alloc = fd_array_map_alloc,
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.map_free = fd_array_map_free,
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.map_get_next_key = array_map_get_next_key,
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.map_lookup_elem = prog_array_map_lookup_elem,
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.map_update_elem = prog_array_map_update_elem,
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.map_delete_elem = prog_array_map_delete_elem,
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.map_lookup_elem = fd_array_map_lookup_elem,
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.map_update_elem = fd_array_map_update_elem,
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.map_delete_elem = fd_array_map_delete_elem,
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.map_fd_get_ptr = prog_fd_array_get_ptr,
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.map_fd_put_ptr = prog_fd_array_put_ptr,
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};
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static struct bpf_map_type_list prog_array_type __read_mostly = {
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@ -450,7 +450,7 @@ static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn)
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tail_call_cnt++;
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prog = READ_ONCE(array->prog[index]);
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prog = READ_ONCE(array->ptrs[index]);
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if (unlikely(!prog))
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goto out;
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@ -72,7 +72,7 @@ static int bpf_map_release(struct inode *inode, struct file *filp)
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/* prog_array stores refcnt-ed bpf_prog pointers
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* release them all when user space closes prog_array_fd
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*/
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bpf_prog_array_map_clear(map);
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bpf_fd_array_map_clear(map);
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bpf_map_put(map);
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return 0;
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