LXR linux/kernel/bpf/sysfs

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Provide kernel BTF information for introspection and use by eBPF tools.
   4 */
   5#include <linux/kernel.h>
   6#include <linux/module.h>
   7#include <linux/kobject.h>
   8#include <linux/init.h>
   9#include <linux/sysfs.h>
  10
  11/* See scripts/link-vmlinux.sh, gen_btf() func for details */
  12extern char __weak __start_BTF[];
  13extern char __weak __stop_BTF[];
  14
  15static ssize_t
  16btf_vmlinux_read(struct file *file, struct kobject *kobj,
  17                 struct bin_attribute *bin_attr,
  18                 char *buf, loff_t off, size_t len)
  19{
  20        memcpy(buf, __start_BTF + off, len);
  21        return len;
  22}
  23
  24static struct bin_attribute bin_attr_btf_vmlinux __ro_after_init = {
  25        .attr = { .name = "vmlinux", .mode = 0444, },
  26        .read = btf_vmlinux_read,
  27};
  28
  29struct kobject *btf_kobj;
  30
  31static int __init btf_vmlinux_init(void)
  32{
  33        bin_attr_btf_vmlinux.size = __stop_BTF - __start_BTF;
  34
  35        if (!__start_BTF || bin_attr_btf_vmlinux.size == 0)
  36                return 0;
  37
  38        btf_kobj = kobject_create_and_add("btf", kernel_kobj);
  39        if (!btf_kobj)
  40                return -ENOMEM;
  41
  42        return sysfs_create_bin_file(btf_kobj, &bin_attr_btf_vmlinux);
  43}
  44
  45subsys_initcall(btf_vmlinux_init);
  46