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// 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";
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