[PATCH v5 net-next 21/29] tracing: allow eBPF programs to call ktime_get_ns() and get_current()

From: Alexei Starovoitov
Date: Sun Aug 24 2014 - 16:25:53 EST


Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxxxx>
---
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 5adaad826471..e866a2fcba8b 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -416,6 +416,8 @@ 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

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