bpf: Fix missing bpf_base_func_proto in cgroup_base_func_proto for CGROUP_NET=n

linux-next build bot reported compile issue [1] with one of its
configs. It looks like when we have CONFIG_NET=n and
CONFIG_BPF{,_SYSCALL}=y, we are missing the bpf_base_func_proto
definition (from net/core/filter.c) in cgroup_base_func_proto.

I'm reshuffling the code a bit to make it work. The common helpers
are moved into kernel/bpf/helpers.c and the bpf_base_func_proto is
exported from there.
Also, bpf_get_raw_cpu_id goes into kernel/bpf/core.c akin to existing
bpf_user_rnd_u32.

[1] https://lore.kernel.org/linux-next/CAKH8qBsBvKHswiX1nx40LgO+BGeTmb1NX8tiTttt_0uu6T3dCA@mail.gmail.com/T/#mff8b0c083314c68c2e2ef0211cb11bc20dc13c72

Fixes: 0456ea170cd6 ("bpf: Enable more helpers for BPF_PROG_TYPE_CGROUP_{DEVICE,SYSCTL,SOCKOPT}")
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200424235941.58382-1-sdf@google.com

1 files changed, 1 insertions, 77 deletions

diff --git a/net/core/filter.c b/net/core/filter.c
index a943df3ad8b0..a605626142b6 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -256,17 +256,6 @@ BPF_CALL_2(bpf_skb_load_helper_32_no_cache, const struct sk_buff *, skb,
 					  offset);
 }
 
-BPF_CALL_0(bpf_get_raw_cpu_id)
-{
-	return raw_smp_processor_id();
-}
-
-static const struct bpf_func_proto bpf_get_raw_smp_processor_id_proto = {
-	.func		= bpf_get_raw_cpu_id,
-	.gpl_only	= false,
-	.ret_type	= RET_INTEGER,
-};
-
 static u32 convert_skb_access(int skb_field, int dst_reg, int src_reg,
 			      struct bpf_insn *insn_buf)
 {
@@ -4205,26 +4194,6 @@ static const struct bpf_func_proto bpf_get_socket_uid_proto = {
 	.arg1_type      = ARG_PTR_TO_CTX,
 };
 
-BPF_CALL_5(bpf_event_output_data, void *, ctx, struct bpf_map *, map, u64, flags,
-	   void *, data, u64, size)
-{
-	if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
-		return -EINVAL;
-
-	return bpf_event_output(map, flags, data, size, NULL, 0, NULL);
-}
-
-const struct bpf_func_proto bpf_event_output_data_proto =  {
-	.func		= bpf_event_output_data,
-	.gpl_only       = true,
-	.ret_type       = RET_INTEGER,
-	.arg1_type      = ARG_PTR_TO_CTX,
-	.arg2_type      = ARG_CONST_MAP_PTR,
-	.arg3_type      = ARG_ANYTHING,
-	.arg4_type      = ARG_PTR_TO_MEM,
-	.arg5_type      = ARG_CONST_SIZE_OR_ZERO,
-};
-
 BPF_CALL_5(bpf_setsockopt, struct bpf_sock_ops_kern *, bpf_sock,
 	   int, level, int, optname, char *, optval, int, optlen)
 {
@@ -5983,52 +5952,7 @@ bool bpf_helper_changes_pkt_data(void *func)
 	return false;
 }
 
-const struct bpf_func_proto *
-bpf_base_func_proto(enum bpf_func_id func_id)
-{
-	switch (func_id) {
-	case BPF_FUNC_map_lookup_elem:
-		return &bpf_map_lookup_elem_proto;
-	case BPF_FUNC_map_update_elem:
-		return &bpf_map_update_elem_proto;
-	case BPF_FUNC_map_delete_elem:
-		return &bpf_map_delete_elem_proto;
-	case BPF_FUNC_map_push_elem:
-		return &bpf_map_push_elem_proto;
-	case BPF_FUNC_map_pop_elem:
-		return &bpf_map_pop_elem_proto;
-	case BPF_FUNC_map_peek_elem:
-		return &bpf_map_peek_elem_proto;
-	case BPF_FUNC_get_prandom_u32:
-		return &bpf_get_prandom_u32_proto;
-	case BPF_FUNC_get_smp_processor_id:
-		return &bpf_get_raw_smp_processor_id_proto;
-	case BPF_FUNC_get_numa_node_id:
-		return &bpf_get_numa_node_id_proto;
-	case BPF_FUNC_tail_call:
-		return &bpf_tail_call_proto;
-	case BPF_FUNC_ktime_get_ns:
-		return &bpf_ktime_get_ns_proto;
-	default:
-		break;
-	}
-
-	if (!capable(CAP_SYS_ADMIN))
-		return NULL;
-
-	switch (func_id) {
-	case BPF_FUNC_spin_lock:
-		return &bpf_spin_lock_proto;
-	case BPF_FUNC_spin_unlock:
-		return &bpf_spin_unlock_proto;
-	case BPF_FUNC_trace_printk:
-		return bpf_get_trace_printk_proto();
-	case BPF_FUNC_jiffies64:
-		return &bpf_jiffies64_proto;
-	default:
-		return NULL;
-	}
-}
+const struct bpf_func_proto bpf_event_output_data_proto __weak;
 
 static const struct bpf_func_proto *
 sock_filter_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)