[PATCH RFC v7 net-next 20/28] tracing: allow eBPF programs to call ktime_get_ns() and get_current()

[Alexei Starovoitov <ast@plumgrid.com>]

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
---
 include/uapi/linux/bpf.h |    2 ++
 kernel/trace/bpf_trace.c |   20 ++++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 1ec3d293d14e..e14e147c8899 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -431,6 +431,8 @@ enum bpf_func_id {
 	BPF_FUNC_memcmp,          /* int bpf_memcmp(void *unsafe_ptr, void *safe_ptr, int size) */
 	BPF_FUNC_dump_stack,      /* void bpf_dump_stack(void) */
 	BPF_FUNC_printk,          /* int bpf_printk(const char *fmt, int fmt_size, ...) */
+	BPF_FUNC_ktime_get_ns,    /* u64 bpf_ktime_get_ns(void) */
+	BPF_FUNC_get_current,     /* struct task_struct *bpf_get_current(void) */
 	__BPF_FUNC_MAX_ID,
 };
 
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index ff98be5a24d6..a98e13e1131b 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -114,6 +114,16 @@ static u64 bpf_printk(u64 r1, u64 fmt_size, u64 r3, u64 r4, u64 r5)
 			      mod_l[2] ? r5 : (u32) r5);
 }
 
+static u64 bpf_ktime_get_ns(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+{
+	return ktime_get_ns();
+}
+
+static u64 bpf_get_current(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+{
+	return (u64) (long) current;
+}
+
 static struct bpf_func_proto tracing_filter_funcs[] = {
 #define FETCH(SIZE)				\
 	[BPF_FUNC_fetch_##SIZE] = {		\
@@ -169,6 +179,16 @@ static struct bpf_func_proto tracing_filter_funcs[] = {
 		.arg1_type = ARG_CONST_MAP_PTR,
 		.arg2_type = ARG_PTR_TO_MAP_KEY,
 	},
+	[BPF_FUNC_ktime_get_ns] = {
+		.func = bpf_ktime_get_ns,
+		.gpl_only = true,
+		.ret_type = RET_INTEGER,
+	},
+	[BPF_FUNC_get_current] = {
+		.func = bpf_get_current,
+		.gpl_only = true,
+		.ret_type = RET_INTEGER,
+	},
 };
 
 static const struct bpf_func_proto *tracing_filter_func_proto(enum bpf_func_id func_id)
-- 
1.7.9.5