[PATCH v3 linux-trace 2/8] tracing: allow eBPF programs to call ktime_get_ns()
From: Alexei Starovoitov <hidden>
Date: 2015-02-10 03:48:28
Also in:
lkml, netdev
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [security & lsm] (security audit and enforcement using bpf), bpf [tracing], the rest, tracing · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, KP Singh, Matt Bobrowski, Song Liu, Linus Torvalds, Steven Rostedt, Masami Hiramatsu
bpf_ktime_get_ns() is used by programs to compue time delta between events or as a timestamp Signed-off-by: Alexei Starovoitov <redacted> --- include/uapi/linux/bpf.h | 1 + kernel/trace/bpf_trace.c | 10 ++++++++++ 2 files changed, 11 insertions(+)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index d73d7d0abe6e..ecae21e58ba3 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h@@ -169,6 +169,7 @@ enum bpf_func_id { BPF_FUNC_fetch_u16, /* u16 bpf_fetch_u16(void *unsafe_ptr) */ BPF_FUNC_fetch_u8, /* u8 bpf_fetch_u8(void *unsafe_ptr) */ BPF_FUNC_probe_memcmp, /* int bpf_probe_memcmp(unsafe_ptr, safe_ptr, size) */ + BPF_FUNC_ktime_get_ns, /* u64 bpf_ktime_get_ns(void) */ __BPF_FUNC_MAX_ID, };
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index ec065e0a364e..e3196266b72f 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c@@ -69,6 +69,11 @@ static u64 bpf_probe_memcmp(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) return -1; } +static u64 bpf_ktime_get_ns(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) +{ + return ktime_get_ns(); +} + static struct bpf_func_proto tp_prog_funcs[] = { #define FETCH(SIZE) \ [BPF_FUNC_fetch_##SIZE] = { \
@@ -90,6 +95,11 @@ static struct bpf_func_proto tp_prog_funcs[] = { .arg2_type = ARG_PTR_TO_STACK, .arg3_type = ARG_CONST_STACK_SIZE, }, + [BPF_FUNC_ktime_get_ns] = { + .func = bpf_ktime_get_ns, + .gpl_only = true, + .ret_type = RET_INTEGER, + }, }; static const struct bpf_func_proto *tp_prog_func_proto(enum bpf_func_id func_id)
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1.7.9.5