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Subject[PATCH net-next v2 2/3] bpf, perf: split bpf_perf_event_output
Date
Split the bpf_perf_event_output() helper as a preparation into
two parts. The new bpf_perf_event_output() will prepare the raw
record itself and test for unknown flags from BPF trace context,
where the __bpf_perf_event_output() does the core work. The
latter will be reused later on from bpf_event_output() directly.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
---
kernel/trace/bpf_trace.c | 35 ++++++++++++++++++++++-------------
1 file changed, 22 insertions(+), 13 deletions(-)

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 35ab1b2..c35883a 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -233,26 +233,17 @@ static const struct bpf_func_proto bpf_perf_event_read_proto = {
.arg2_type = ARG_ANYTHING,
};

-static u64 bpf_perf_event_output(u64 r1, u64 r2, u64 flags, u64 r4, u64 size)
+static __always_inline u64
+__bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map,
+ u64 flags, struct perf_raw_record *raw)
{
- struct pt_regs *regs = (struct pt_regs *) (long) r1;
- struct bpf_map *map = (struct bpf_map *) (long) r2;
struct bpf_array *array = container_of(map, struct bpf_array, map);
unsigned int cpu = smp_processor_id();
u64 index = flags & BPF_F_INDEX_MASK;
- void *data = (void *) (long) r4;
struct perf_sample_data sample_data;
struct bpf_event_entry *ee;
struct perf_event *event;
- struct perf_raw_record raw = {
- .frag = {
- .size = size,
- .data = data,
- },
- };

- if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
- return -EINVAL;
if (index == BPF_F_CURRENT_CPU)
index = cpu;
if (unlikely(index >= array->map.max_entries))
@@ -271,11 +262,29 @@ static u64 bpf_perf_event_output(u64 r1, u64 r2, u64 flags, u64 r4, u64 size)
return -EOPNOTSUPP;

perf_sample_data_init(&sample_data, 0, 0);
- sample_data.raw = &raw;
+ sample_data.raw = raw;
perf_event_output(event, &sample_data, regs);
return 0;
}

+static u64 bpf_perf_event_output(u64 r1, u64 r2, u64 flags, u64 r4, u64 size)
+{
+ struct pt_regs *regs = (struct pt_regs *)(long) r1;
+ struct bpf_map *map = (struct bpf_map *)(long) r2;
+ void *data = (void *)(long) r4;
+ struct perf_raw_record raw = {
+ .frag = {
+ .size = size,
+ .data = data,
+ },
+ };
+
+ if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
+ return -EINVAL;
+
+ return __bpf_perf_event_output(regs, map, flags, &raw);
+}
+
static const struct bpf_func_proto bpf_perf_event_output_proto = {
.func = bpf_perf_event_output,
.gpl_only = true,
--
1.9.3
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