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ab38e84ba9
Look for .rodata maps, find ones with 'bpf_metadata_' variables, extract
their values as strings, and create a new PERF_RECORD_BPF_METADATA
synthetic event using that data. The code gets invoked from the existing
routine perf_event__synthesize_one_bpf_prog().
For example, a BPF program with the following variables:
const char bpf_metadata_version[] SEC(".rodata") = "3.14159";
int bpf_metadata_value[] SEC(".rodata") = 42;
would generate a PERF_RECORD_BPF_METADATA record with:
.prog_name = <BPF program name, e.g. "bpf_prog_a1b2c3_foo">
.nr_entries = 2
.entries[0].key = "version"
.entries[0].value = "3.14159"
.entries[1].key = "value"
.entries[1].value = "42"
Each of the BPF programs and subprograms that share those variables would
get a distinct PERF_RECORD_BPF_METADATA record, with the ".prog_name"
showing the name of each program or subprogram. The prog_name is
deliberately the same as the ".name" field in the corresponding
PERF_RECORD_KSYMBOL record.
This code only gets invoked if support for displaying BTF char arrays
as strings is detected.
Signed-off-by: Blake Jones <blakejones@google.com>
Link: https://lore.kernel.org/r/20250612194939.162730-3-blakejones@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>