bpf: Make perf_event_read_output accessible in all program types.

The perf_event_read_event_output helper is currently only available to
tracing protrams, but is useful for other BPF programs like sched_ext
schedulers. When the helper is available, provide its bpf_func_proto
directly from the bpf base_proto.

Signed-off-by: Emil Tsalapatis (Meta) <emil@etsalapatis.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20250318030753.10949-1-emil@etsalapatis.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 0d7b70124d81e6233fc6f5c687407106d3018f28..973a88d9b52bc9786929a03456d2726d27e93700 100644 (file)
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2059,6 +2059,8 @@ int bpf_prog_calc_tag(struct bpf_prog *fp);
 const struct bpf_func_proto *bpf_get_trace_printk_proto(void);
 const struct bpf_func_proto *bpf_get_trace_vprintk_proto(void);
 
+const struct bpf_func_proto *bpf_get_perf_event_read_value_proto(void);
+
 typedef unsigned long (*bpf_ctx_copy_t)(void *dst, const void *src,
                                        unsigned long off, unsigned long len);
 typedef u32 (*bpf_convert_ctx_access_t)(enum bpf_access_type type,

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 62cb9557ad3bee4742eb4583f8ca04ccde07d9e1..ba6b6118cf504041278d05417c4212d57be6fca0 100644 (file)
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -2972,6 +2972,11 @@ const struct bpf_func_proto * __weak bpf_get_trace_vprintk_proto(void)
        return NULL;
 }
 
+const struct bpf_func_proto * __weak bpf_get_perf_event_read_value_proto(void)
+{
+       return NULL;
+}
+
 u64 __weak
 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
                 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 5449756ba102e32228a34cf054e085b4fefee24c..ddaa41a70676cfefad3de13cf673aeee3345990c 100644 (file)
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -2056,6 +2056,8 @@ bpf_base_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
                return &bpf_task_pt_regs_proto;
        case BPF_FUNC_trace_vprintk:
                return bpf_get_trace_vprintk_proto();
+       case BPF_FUNC_perf_event_read_value:
+               return bpf_get_perf_event_read_value_proto();
        default:
                return NULL;
        }

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 13bef2462e94b008a90e4d34b8824add336fbf43..6b07fa7081d94796f57d5ed9d03fadd1043689d7 100644 (file)
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -607,6 +607,11 @@ static const struct bpf_func_proto bpf_perf_event_read_value_proto = {
        .arg4_type      = ARG_CONST_SIZE,
 };
 
+const struct bpf_func_proto *bpf_get_perf_event_read_value_proto(void)
+{
+       return &bpf_perf_event_read_value_proto;
+}
+
 static __always_inline u64
 __bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map,
                        u64 flags, struct perf_raw_record *raw,