Commit f1b9509c authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Daniel Borkmann
Browse files

bpf: Replace prog_raw_tp+btf_id with prog_tracing 



The bpf program type raw_tp together with 'expected_attach_type'
was the most appropriate api to indicate BTF-enabled raw_tp programs.
But during development it became apparent that 'expected_attach_type'
cannot be used and new 'attach_btf_id' field had to be introduced.
Which means that the information is duplicated in two fields where
one of them is ignored.
Clean it up by introducing new program type where both
'expected_attach_type' and 'attach_btf_id' fields have
specific meaning.
In the future 'expected_attach_type' will be extended
with other attach points that have similar semantics to raw_tp.
This patch is replacing BTF-enabled BPF_PROG_TYPE_RAW_TRACEPOINT with
prog_type = BPF_RPOG_TYPE_TRACING
expected_attach_type = BPF_TRACE_RAW_TP
attach_btf_id = btf_id of raw tracepoint inside the kernel
Future patches will add
expected_attach_type = BPF_TRACE_FENTRY or BPF_TRACE_FEXIT
where programs have the same input context and the same helpers,
but different attach points.

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAndrii Nakryiko <andriin@fb.com>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191030223212.953010-2-ast@kernel.org
parent af91acbc

include/linux/bpf.h

+5 −0
Original line number Diff line number Diff line
@@ -373,6 +373,11 @@ enum bpf_cgroup_storage_type { 


#define MAX_BPF_CGROUP_STORAGE_TYPE __BPF_CGROUP_STORAGE_MAX



/* The longest tracepoint has 12 args.

 * See include/trace/bpf_probe.h

 */

#define MAX_BPF_FUNC_ARGS 12



struct bpf_prog_stats {

	u64 cnt;

	u64 nsecs;

include/linux/bpf_types.h

+1 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ BPF_PROG_TYPE(BPF_PROG_TYPE_TRACEPOINT, tracepoint) 
BPF_PROG_TYPE(BPF_PROG_TYPE_PERF_EVENT, perf_event)

BPF_PROG_TYPE(BPF_PROG_TYPE_RAW_TRACEPOINT, raw_tracepoint)

BPF_PROG_TYPE(BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE, raw_tracepoint_writable)

BPF_PROG_TYPE(BPF_PROG_TYPE_TRACING, tracing)

#endif

#ifdef CONFIG_CGROUP_BPF

BPF_PROG_TYPE(BPF_PROG_TYPE_CGROUP_DEVICE, cg_dev)

include/uapi/linux/bpf.h

+2 −0
Original line number Diff line number Diff line
@@ -173,6 +173,7 @@ enum bpf_prog_type { 
	BPF_PROG_TYPE_CGROUP_SYSCTL,

	BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,

	BPF_PROG_TYPE_CGROUP_SOCKOPT,

	BPF_PROG_TYPE_TRACING,

};



enum bpf_attach_type {
@@ -199,6 +200,7 @@ enum bpf_attach_type { 
	BPF_CGROUP_UDP6_RECVMSG,

	BPF_CGROUP_GETSOCKOPT,

	BPF_CGROUP_SETSOCKOPT,

	BPF_TRACE_RAW_TP,

	__MAX_BPF_ATTACH_TYPE

};

kernel/bpf/syscall.c

+3 −3
Original line number Diff line number Diff line
@@ -1571,7 +1571,7 @@ bpf_prog_load_check_attach(enum bpf_prog_type prog_type, 
			   u32 btf_id)

{

	switch (prog_type) {

	case BPF_PROG_TYPE_RAW_TRACEPOINT:

	case BPF_PROG_TYPE_TRACING:

		if (btf_id > BTF_MAX_TYPE)

			return -EINVAL;

		break;
@@ -1833,13 +1833,13 @@ static int bpf_raw_tracepoint_open(const union bpf_attr *attr) 
		return PTR_ERR(prog);



	if (prog->type != BPF_PROG_TYPE_RAW_TRACEPOINT &&

	    prog->type != BPF_PROG_TYPE_TRACING &&

	    prog->type != BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE) {

		err = -EINVAL;

		goto out_put_prog;

	}



	if (prog->type == BPF_PROG_TYPE_RAW_TRACEPOINT &&

	    prog->aux->attach_btf_id) {

	if (prog->type == BPF_PROG_TYPE_TRACING) {

		if (attr->raw_tracepoint.name) {

			/* raw_tp name should not be specified in raw_tp

			 * programs that were verified via in-kernel BTF info

kernel/bpf/verifier.c

+24 −10
Original line number Diff line number Diff line
@@ -9381,24 +9381,36 @@ static int check_attach_btf_id(struct bpf_verifier_env *env) 
{

	struct bpf_prog *prog = env->prog;

	u32 btf_id = prog->aux->attach_btf_id;

	const char prefix[] = "btf_trace_";

	const struct btf_type *t;

	const char *tname;



	if (prog->type == BPF_PROG_TYPE_RAW_TRACEPOINT && btf_id) {

		const char prefix[] = "btf_trace_";

	if (prog->type != BPF_PROG_TYPE_TRACING)

		return 0;



	if (!btf_id) {

		verbose(env, "Tracing programs must provide btf_id\n");

		return -EINVAL;

	}

	t = btf_type_by_id(btf_vmlinux, btf_id);

	if (!t) {

		verbose(env, "attach_btf_id %u is invalid\n", btf_id);

		return -EINVAL;

	}

	tname = btf_name_by_offset(btf_vmlinux, t->name_off);

	if (!tname) {

		verbose(env, "attach_btf_id %u doesn't have a name\n", btf_id);

		return -EINVAL;

	}



	switch (prog->expected_attach_type) {

	case BPF_TRACE_RAW_TP:

		if (!btf_type_is_typedef(t)) {

			verbose(env, "attach_btf_id %u is not a typedef\n",

				btf_id);

			return -EINVAL;

		}

		tname = btf_name_by_offset(btf_vmlinux, t->name_off);

		if (!tname || strncmp(prefix, tname, sizeof(prefix) - 1)) {

		if (strncmp(prefix, tname, sizeof(prefix) - 1)) {

			verbose(env, "attach_btf_id %u points to wrong type name %s\n",

				btf_id, tname);

			return -EINVAL;
@@ -9419,8 +9431,10 @@ static int check_attach_btf_id(struct bpf_verifier_env *env) 
		prog->aux->attach_func_name = tname;

		prog->aux->attach_func_proto = t;

		prog->aux->attach_btf_trace = true;

	}

		return 0;

	default:

		return -EINVAL;

	}

}



int bpf_check(struct bpf_prog **prog, union bpf_attr *attr,

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