diff options
| author | Lorenz Bauer <lmb@cloudflare.com> | 2020-09-21 13:12:20 +0100 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-09-21 15:00:40 -0700 |
| commit | 9436ef6e862b9ca22e5b12f87b106e07d5af4cae (patch) | |
| tree | d492819683666eba4815ed5d705e7a9cf281c3fa /kernel/bpf/stackmap.c | |
| parent | 27774b7073b5d520c80f1fcb8e9993fc139f21bd (diff) | |
bpf: Allow specifying a BTF ID per argument in function protos
Function prototypes using ARG_PTR_TO_BTF_ID currently use two ways to signal
which BTF IDs are acceptable. First, bpf_func_proto.btf_id is an array of
IDs, one for each argument. This array is only accessed up to the highest
numbered argument that uses ARG_PTR_TO_BTF_ID and may therefore be less than
five arguments long. It usually points at a BTF_ID_LIST. Second, check_btf_id
is a function pointer that is called by the verifier if present. It gets the
actual BTF ID of the register, and the argument number we're currently checking.
It turns out that the only user check_arg_btf_id ignores the argument, and is
simply used to check whether the BTF ID has a struct sock_common at it's start.
Replace both of these mechanisms with an explicit BTF ID for each argument
in a function proto. Thanks to btf_struct_ids_match this is very flexible:
check_arg_btf_id can be replaced by requiring struct sock_common.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200921121227.255763-5-lmb@cloudflare.com
Diffstat (limited to 'kernel/bpf/stackmap.c')
| -rw-r--r-- | kernel/bpf/stackmap.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index a2fa006f430e..06065fa27124 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -665,18 +665,17 @@ BPF_CALL_4(bpf_get_task_stack, struct task_struct *, task, void *, buf, return __bpf_get_stack(regs, task, NULL, buf, size, flags); } -BTF_ID_LIST(bpf_get_task_stack_btf_ids) -BTF_ID(struct, task_struct) +BTF_ID_LIST_SINGLE(bpf_get_task_stack_btf_ids, struct, task_struct) const struct bpf_func_proto bpf_get_task_stack_proto = { .func = bpf_get_task_stack, .gpl_only = false, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_BTF_ID, + .arg1_btf_id = &bpf_get_task_stack_btf_ids[0], .arg2_type = ARG_PTR_TO_UNINIT_MEM, .arg3_type = ARG_CONST_SIZE_OR_ZERO, .arg4_type = ARG_ANYTHING, - .btf_id = bpf_get_task_stack_btf_ids, }; BPF_CALL_4(bpf_get_stack_pe, struct bpf_perf_event_data_kern *, ctx, |