// SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2019 Facebook #include <stddef.h> #include <linux/ptrace.h> #include <linux/bpf.h> #include <bpf/bpf_helpers.h> #include <bpf/bpf_tracing.h> int valid = 0; int required_size_out = 0; int written_stack_out = 0; int written_global_out = 0; struct { __u64 _a; __u64 _b; __u64 _c; } fpbe[30] = {0}; SEC("perf_event") int perf_branches(void *ctx) { __u64 entries[4 * 3] = {0}; int required_size, written_stack, written_global; /* write to stack */ written_stack = bpf_read_branch_records(ctx, entries, sizeof(entries), 0); /* ignore spurious events */ if (!written_stack) return 1; /* get required size */ required_size = bpf_read_branch_records(ctx, NULL, 0, BPF_F_GET_BRANCH_RECORDS_SIZE); written_global = bpf_read_branch_records(ctx, fpbe, sizeof(fpbe), 0); /* ignore spurious events */ if (!written_global) return 1; required_size_out = required_size; written_stack_out = written_stack; written_global_out = written_global; valid = 1; return 0; } char _license[] SEC("license") = "GPL";