bpf: introduce bpf_perf_event_output() helper
This helper is used to send raw data from eBPF program into special PERF_TYPE_SOFTWARE/PERF_COUNT_SW_BPF_OUTPUT perf_event. User space needs to perf_event_open() it (either for one or all cpus) and store FD into perf_event_array (similar to bpf_perf_event_read() helper) before eBPF program can send data into it. Today the programs triggered by kprobe collect the data and either store it into the maps or print it via bpf_trace_printk() where latter is the debug facility and not suitable to stream the data. This new helper replaces such bpf_trace_printk() usage and allows programs to have dedicated channel into user space for post-processing of the raw data collected. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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fa128e6a14
Коммит
a43eec3042
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@ -287,6 +287,17 @@ enum bpf_func_id {
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* Return: realm if != 0
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*/
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BPF_FUNC_get_route_realm,
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/**
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* bpf_perf_event_output(ctx, map, index, data, size) - output perf raw sample
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* @ctx: struct pt_regs*
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* @map: pointer to perf_event_array map
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* @index: index of event in the map
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* @data: data on stack to be output as raw data
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* @size: size of data
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* Return: 0 on success
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*/
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BPF_FUNC_perf_event_output,
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__BPF_FUNC_MAX_ID,
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};
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@ -110,6 +110,7 @@ enum perf_sw_ids {
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PERF_COUNT_SW_ALIGNMENT_FAULTS = 7,
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PERF_COUNT_SW_EMULATION_FAULTS = 8,
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PERF_COUNT_SW_DUMMY = 9,
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PERF_COUNT_SW_BPF_OUTPUT = 10,
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PERF_COUNT_SW_MAX, /* non-ABI */
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};
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@ -295,6 +295,8 @@ static void *perf_event_fd_array_get_ptr(struct bpf_map *map, int fd)
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return (void *)attr;
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if (attr->type != PERF_TYPE_RAW &&
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!(attr->type == PERF_TYPE_SOFTWARE &&
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attr->config == PERF_COUNT_SW_BPF_OUTPUT) &&
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attr->type != PERF_TYPE_HARDWARE) {
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perf_event_release_kernel(event);
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return ERR_PTR(-EINVAL);
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@ -245,6 +245,7 @@ static const struct {
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} func_limit[] = {
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{BPF_MAP_TYPE_PROG_ARRAY, BPF_FUNC_tail_call},
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{BPF_MAP_TYPE_PERF_EVENT_ARRAY, BPF_FUNC_perf_event_read},
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{BPF_MAP_TYPE_PERF_EVENT_ARRAY, BPF_FUNC_perf_event_output},
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};
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static void print_verifier_state(struct verifier_env *env)
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@ -910,7 +911,7 @@ static int check_map_func_compatibility(struct bpf_map *map, int func_id)
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* don't allow any other map type to be passed into
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* the special func;
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*/
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if (bool_map != bool_func)
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if (bool_func && bool_map != bool_func)
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return -EINVAL;
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}
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@ -215,6 +215,50 @@ const struct bpf_func_proto bpf_perf_event_read_proto = {
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.arg2_type = ARG_ANYTHING,
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};
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static u64 bpf_perf_event_output(u64 r1, u64 r2, u64 index, u64 r4, u64 size)
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{
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struct pt_regs *regs = (struct pt_regs *) (long) r1;
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struct bpf_map *map = (struct bpf_map *) (long) r2;
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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void *data = (void *) (long) r4;
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struct perf_sample_data sample_data;
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struct perf_event *event;
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struct perf_raw_record raw = {
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.size = size,
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.data = data,
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};
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if (unlikely(index >= array->map.max_entries))
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return -E2BIG;
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event = (struct perf_event *)array->ptrs[index];
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if (unlikely(!event))
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return -ENOENT;
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if (unlikely(event->attr.type != PERF_TYPE_SOFTWARE ||
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event->attr.config != PERF_COUNT_SW_BPF_OUTPUT))
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return -EINVAL;
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if (unlikely(event->oncpu != smp_processor_id()))
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return -EOPNOTSUPP;
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perf_sample_data_init(&sample_data, 0, 0);
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sample_data.raw = &raw;
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perf_event_output(event, &sample_data, regs);
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return 0;
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}
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static const struct bpf_func_proto bpf_perf_event_output_proto = {
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.func = bpf_perf_event_output,
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.gpl_only = false,
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.ret_type = RET_INTEGER,
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.arg1_type = ARG_PTR_TO_CTX,
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.arg2_type = ARG_CONST_MAP_PTR,
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.arg3_type = ARG_ANYTHING,
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.arg4_type = ARG_PTR_TO_STACK,
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.arg5_type = ARG_CONST_STACK_SIZE,
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};
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static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func_id)
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{
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switch (func_id) {
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@ -242,6 +286,8 @@ static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func
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return &bpf_get_smp_processor_id_proto;
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case BPF_FUNC_perf_event_read:
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return &bpf_perf_event_read_proto;
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case BPF_FUNC_perf_event_output:
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return &bpf_perf_event_output_proto;
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default:
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return NULL;
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}
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