| Message ID | 20200121120512.758929-3-jolsa@kernel.org |
|---|---|
| State | Changes Requested |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | bpf: Add trampoline helpers | expand |
On Tue, Jan 21, 2020 at 01:05:08PM +0100, Jiri Olsa wrote: > Adding support to use perf_event_output in > BPF_TRACE_FENTRY/BPF_TRACE_FEXIT programs. > > Using nesting regs array from raw tracepoint helpers. > > Signed-off-by: Jiri Olsa <jolsa@kernel.org> > --- > kernel/trace/bpf_trace.c | 41 ++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 41 insertions(+) > > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > index 19e793aa441a..6a18e2ae6e30 100644 > --- a/kernel/trace/bpf_trace.c > +++ b/kernel/trace/bpf_trace.c > @@ -1172,6 +1172,43 @@ raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) > } > } > > +BPF_CALL_5(bpf_perf_event_output_kfunc, void *, ctx, struct bpf_map *, map, > + u64, flags, void *, data, u64, size) > +{ > + struct pt_regs *regs = get_bpf_raw_tp_regs(); > + int ret; > + > + if (IS_ERR(regs)) > + return PTR_ERR(regs); > + > + perf_fetch_caller_regs(regs); > + ret = ____bpf_perf_event_output(regs, map, flags, data, size); > + put_bpf_raw_tp_regs(); > + return ret; > +} I'm not sure why copy paste bpf_perf_event_output_raw_tp() into new function. > @@ -1181,6 +1218,10 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) > return &bpf_skb_output_proto; > #endif > default: > + if (prog->expected_attach_type == BPF_TRACE_FENTRY || > + prog->expected_attach_type == BPF_TRACE_FEXIT) > + return kfunc_prog_func_proto(func_id, prog); > + > return raw_tp_prog_func_proto(func_id, prog); Are you saying bpf_perf_event_output_raw_tp() for some reason didn't work for fentry/fexit? But above is exact copy-paste and it somehow worked? Ditto for patches 3,4.
On Tue, Jan 21, 2020 at 04:03:23PM -0800, Alexei Starovoitov wrote: > On Tue, Jan 21, 2020 at 01:05:08PM +0100, Jiri Olsa wrote: > > Adding support to use perf_event_output in > > BPF_TRACE_FENTRY/BPF_TRACE_FEXIT programs. > > > > Using nesting regs array from raw tracepoint helpers. > > > > Signed-off-by: Jiri Olsa <jolsa@kernel.org> > > --- > > kernel/trace/bpf_trace.c | 41 ++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 41 insertions(+) > > > > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > > index 19e793aa441a..6a18e2ae6e30 100644 > > --- a/kernel/trace/bpf_trace.c > > +++ b/kernel/trace/bpf_trace.c > > @@ -1172,6 +1172,43 @@ raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) > > } > > } > > > > +BPF_CALL_5(bpf_perf_event_output_kfunc, void *, ctx, struct bpf_map *, map, > > + u64, flags, void *, data, u64, size) > > +{ > > + struct pt_regs *regs = get_bpf_raw_tp_regs(); > > + int ret; > > + > > + if (IS_ERR(regs)) > > + return PTR_ERR(regs); > > + > > + perf_fetch_caller_regs(regs); > > + ret = ____bpf_perf_event_output(regs, map, flags, data, size); > > + put_bpf_raw_tp_regs(); > > + return ret; > > +} > > I'm not sure why copy paste bpf_perf_event_output_raw_tp() into new function. > > > @@ -1181,6 +1218,10 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) > > return &bpf_skb_output_proto; > > #endif > > default: > > + if (prog->expected_attach_type == BPF_TRACE_FENTRY || > > + prog->expected_attach_type == BPF_TRACE_FEXIT) > > + return kfunc_prog_func_proto(func_id, prog); > > + > > return raw_tp_prog_func_proto(func_id, prog); > > Are you saying bpf_perf_event_output_raw_tp() for some reason > didn't work for fentry/fexit? > But above is exact copy-paste and it somehow worked? > > Ditto for patches 3,4. ugh right.. did not realize that after switching to the rawtp regs nest arrays it's identical and we don't need that jirka
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 19e793aa441a..6a18e2ae6e30 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1172,6 +1172,43 @@ raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) } } +BPF_CALL_5(bpf_perf_event_output_kfunc, void *, ctx, struct bpf_map *, map, + u64, flags, void *, data, u64, size) +{ + struct pt_regs *regs = get_bpf_raw_tp_regs(); + int ret; + + if (IS_ERR(regs)) + return PTR_ERR(regs); + + perf_fetch_caller_regs(regs); + ret = ____bpf_perf_event_output(regs, map, flags, data, size); + put_bpf_raw_tp_regs(); + return ret; +} + +static const struct bpf_func_proto bpf_perf_event_output_proto_kfunc = { + .func = bpf_perf_event_output_kfunc, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_CONST_MAP_PTR, + .arg3_type = ARG_ANYTHING, + .arg4_type = ARG_PTR_TO_MEM, + .arg5_type = ARG_CONST_SIZE_OR_ZERO, +}; + +static const struct bpf_func_proto * +kfunc_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) +{ + switch (func_id) { + case BPF_FUNC_perf_event_output: + return &bpf_perf_event_output_proto_kfunc; + default: + return tracing_func_proto(func_id, prog); + } +} + static const struct bpf_func_proto * tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { @@ -1181,6 +1218,10 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_skb_output_proto; #endif default: + if (prog->expected_attach_type == BPF_TRACE_FENTRY || + prog->expected_attach_type == BPF_TRACE_FEXIT) + return kfunc_prog_func_proto(func_id, prog); + return raw_tp_prog_func_proto(func_id, prog); } }
Adding support to use perf_event_output in BPF_TRACE_FENTRY/BPF_TRACE_FEXIT programs. Using nesting regs array from raw tracepoint helpers. Signed-off-by: Jiri Olsa <jolsa@kernel.org> --- kernel/trace/bpf_trace.c | 41 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+)