1341dfcf8SAndrii Nakryiko // SPDX-License-Identifier: GPL-2.0
2341dfcf8SAndrii Nakryiko /*
3341dfcf8SAndrii Nakryiko * Provide kernel BTF information for introspection and use by eBPF tools.
4341dfcf8SAndrii Nakryiko */
5341dfcf8SAndrii Nakryiko #include <linux/kernel.h>
6341dfcf8SAndrii Nakryiko #include <linux/module.h>
7341dfcf8SAndrii Nakryiko #include <linux/kobject.h>
8341dfcf8SAndrii Nakryiko #include <linux/init.h>
9341dfcf8SAndrii Nakryiko #include <linux/sysfs.h>
10341dfcf8SAndrii Nakryiko
11341dfcf8SAndrii Nakryiko /* See scripts/link-vmlinux.sh, gen_btf() func for details */
1290ceddcbSFangrui Song extern char __weak __start_BTF[];
1390ceddcbSFangrui Song extern char __weak __stop_BTF[];
14341dfcf8SAndrii Nakryiko
15341dfcf8SAndrii Nakryiko static ssize_t
btf_vmlinux_read(struct file * file,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t len)167fd78568SAndrii Nakryiko btf_vmlinux_read(struct file *file, struct kobject *kobj,
17341dfcf8SAndrii Nakryiko struct bin_attribute *bin_attr,
18341dfcf8SAndrii Nakryiko char *buf, loff_t off, size_t len)
19341dfcf8SAndrii Nakryiko {
2090ceddcbSFangrui Song memcpy(buf, __start_BTF + off, len);
21341dfcf8SAndrii Nakryiko return len;
22341dfcf8SAndrii Nakryiko }
23341dfcf8SAndrii Nakryiko
247fd78568SAndrii Nakryiko static struct bin_attribute bin_attr_btf_vmlinux __ro_after_init = {
257fd78568SAndrii Nakryiko .attr = { .name = "vmlinux", .mode = 0444, },
267fd78568SAndrii Nakryiko .read = btf_vmlinux_read,
27341dfcf8SAndrii Nakryiko };
28341dfcf8SAndrii Nakryiko
29*36e68442SAndrii Nakryiko struct kobject *btf_kobj;
30341dfcf8SAndrii Nakryiko
btf_vmlinux_init(void)317fd78568SAndrii Nakryiko static int __init btf_vmlinux_init(void)
32341dfcf8SAndrii Nakryiko {
33e23bb04bSTony Ambardar bin_attr_btf_vmlinux.size = __stop_BTF - __start_BTF;
34e23bb04bSTony Ambardar
35e23bb04bSTony Ambardar if (!__start_BTF || bin_attr_btf_vmlinux.size == 0)
36341dfcf8SAndrii Nakryiko return 0;
37341dfcf8SAndrii Nakryiko
38341dfcf8SAndrii Nakryiko btf_kobj = kobject_create_and_add("btf", kernel_kobj);
39e0325006SWei Yongjun if (!btf_kobj)
40e0325006SWei Yongjun return -ENOMEM;
41341dfcf8SAndrii Nakryiko
427fd78568SAndrii Nakryiko return sysfs_create_bin_file(btf_kobj, &bin_attr_btf_vmlinux);
43341dfcf8SAndrii Nakryiko }
44341dfcf8SAndrii Nakryiko
457fd78568SAndrii Nakryiko subsys_initcall(btf_vmlinux_init);
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