[RFC PATCH 02/11] bpf: add BPF_PROG_TYPE_DTRACE

Kris Van Hees
2019-05-21T20:40:27Z

Add a new BPF program type for DTrace. The program type is not compiled
right now because the CONFIG_DTRACE option does not exist yet. It will
be added in a following commit.

Three commits are involved here:

1. add the BPF program type (conditional on a to-be-added option)
2. add the BPF_PROG_TYPE_DTRACE implementation (building not enabled)
3. add the CONFIG_DTRACE option and enable compilation of the prog type
implementation

The reason for this sequence is to ensure that the kernel tree remains
buildable between these commits.

Signed-off-by: Kris Van Hees <kris.van.hees@oracle.com>
Reviewed-by: Nick Alcock <nick.alcock@oracle.com>
---
include/linux/bpf_types.h | 3 +++
include/uapi/linux/bpf.h | 1 +
samples/bpf/bpf_load.c | 10 +++++++---
tools/include/uapi/linux/bpf.h | 1 +
tools/lib/bpf/libbpf.c | 2 ++
tools/lib/bpf/libbpf_probes.c | 1 +
6 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h
index 5a9975678d6f..908f2e4f597e 100644
--- a/include/linux/bpf_types.h
+++ b/include/linux/bpf_types.h
@@ -26,6 +26,9 @@ 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)
+#ifdef CONFIG_DTRACE
+BPF_PROG_TYPE(BPF_PROG_TYPE_DTRACE, dtrace)
+#endif
#endif
#ifdef CONFIG_CGROUP_BPF
BPF_PROG_TYPE(BPF_PROG_TYPE_CGROUP_DEVICE, cg_dev)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 61abe6b56948..7bcb707539d1 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -170,6 +170,7 @@ enum bpf_prog_type {
BPF_PROG_TYPE_FLOW_DISSECTOR,
BPF_PROG_TYPE_CGROUP_SYSCTL,
BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
+ BPF_PROG_TYPE_DTRACE,
};

enum bpf_attach_type {
diff --git a/samples/bpf/bpf_load.c b/samples/bpf/bpf_load.c
index eae7b635343d..4812295484a1 100644
--- a/samples/bpf/bpf_load.c
+++ b/samples/bpf/bpf_load.c
@@ -87,6 +87,7 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
bool is_sockops = strncmp(event, "sockops", 7) == 0;
bool is_sk_skb = strncmp(event, "sk_skb", 6) == 0;
bool is_sk_msg = strncmp(event, "sk_msg", 6) == 0;
+ bool is_dtrace = strncmp(event, "dtrace", 6) == 0;
size_t insns_cnt = size / sizeof(struct bpf_insn);
enum bpf_prog_type prog_type;
char buf[256];
@@ -120,6 +121,8 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
prog_type = BPF_PROG_TYPE_SK_SKB;
} else if (is_sk_msg) {
prog_type = BPF_PROG_TYPE_SK_MSG;
+ } else if (is_dtrace) {
+ prog_type = BPF_PROG_TYPE_DTRACE;
} else {
printf("Unknown event '%s'\n", event);
return -1;
@@ -140,8 +143,8 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
if (is_xdp || is_perf_event || is_cgroup_skb || is_cgroup_sk)
return 0;

- if (is_socket || is_sockops || is_sk_skb || is_sk_msg) {
- if (is_socket)
+ if (is_socket || is_sockops || is_sk_skb || is_sk_msg || is_dtrace) {
+ if (is_socket || is_dtrace)
event += 6;
else
event += 7;
@@ -643,7 +646,8 @@ static int do_load_bpf_file(const char *path, fixup_map_cb fixup_map)
memcmp(shname, "cgroup/", 7) == 0 ||
memcmp(shname, "sockops", 7) == 0 ||
memcmp(shname, "sk_skb", 6) == 0 ||
- memcmp(shname, "sk_msg", 6) == 0) {
+ memcmp(shname, "sk_msg", 6) == 0 ||
+ memcmp(shname, "dtrace", 6) == 0) {
ret = load_and_attach(shname, data->d_buf,
data->d_size);
if (ret != 0)
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 61abe6b56948..7bcb707539d1 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -170,6 +170,7 @@ enum bpf_prog_type {
BPF_PROG_TYPE_FLOW_DISSECTOR,
BPF_PROG_TYPE_CGROUP_SYSCTL,
BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
+ BPF_PROG_TYPE_DTRACE,
};

enum bpf_attach_type {
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 7e3b79d7c25f..44704a7d395d 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -2269,6 +2269,7 @@ static bool bpf_prog_type__needs_kver(enum bpf_prog_type type)
case BPF_PROG_TYPE_CGROUP_SYSCTL:
return false;
case BPF_PROG_TYPE_KPROBE:
+ case BPF_PROG_TYPE_DTRACE:
default:
return true;
}
@@ -3209,6 +3210,7 @@ static const struct {
BPF_CGROUP_UDP6_SENDMSG),
BPF_EAPROG_SEC("cgroup/sysctl", BPF_PROG_TYPE_CGROUP_SYSCTL,
BPF_CGROUP_SYSCTL),
+ BPF_PROG_SEC("dtrace/", BPF_PROG_TYPE_DTRACE),
};

#undef BPF_PROG_SEC_IMPL
diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c
index 5e2aa83f637a..544d8530915e 100644
--- a/tools/lib/bpf/libbpf_probes.c
+++ b/tools/lib/bpf/libbpf_probes.c
@@ -101,6 +101,7 @@ probe_load(enum bpf_prog_type prog_type, const struct bpf_insn *insns,
case BPF_PROG_TYPE_SK_REUSEPORT:
case BPF_PROG_TYPE_FLOW_DISSECTOR:
case BPF_PROG_TYPE_CGROUP_SYSCTL:
+ case BPF_PROG_TYPE_DTRACE:
default:
break;
}
--
2.20.1