// SPDX-License-Identifier: GPL-2.0/* * Provide kernel BTF information for introspection and use by eBPF tools. */#include <linux/kernel.h>#include <linux/module.h>#include <linux/kobject.h>#include <linux/init.h>#include <linux/sysfs.h>#include <linux/mm.h>#include <linux/io.h>#include <linux/btf.h> /* See scripts/link-vmlinux.sh, gen_btf() func for details */extern char __start_BTF[];extern char __stop_BTF[]; static int btf_sysfs_vmlinux_mmap(struct file *filp, struct kobject *kobj,				  const struct bin_attribute *attr,				  struct vm_area_struct *vma){	unsigned long pages = PAGE_ALIGN(attr->size) >> PAGE_SHIFT;	size_t vm_size = vma->vm_end - vma->vm_start;	phys_addr_t addr = __pa_symbol(__start_BTF);	unsigned long pfn = addr >> PAGE_SHIFT; 	if (attr->private != __start_BTF || !PAGE_ALIGNED(addr))		return -EINVAL; 	if (vma->vm_pgoff)		return -EINVAL; 	if (vma->vm_flags & (VM_WRITE | VM_EXEC | VM_MAYSHARE))		return -EACCES; 	if (pfn + pages < pfn)		return -EINVAL; 	if ((vm_size >> PAGE_SHIFT) > pages)		return -EINVAL; 	vm_flags_mod(vma, VM_DONTDUMP, VM_MAYEXEC | VM_MAYWRITE);	return remap_pfn_range(vma, vma->vm_start, pfn, vm_size, vma->vm_page_prot);} static struct bin_attribute bin_attr_btf_vmlinux __ro_after_init = {	.attr = { .name = "vmlinux", .mode = 0444, },	.read = sysfs_bin_attr_simple_read,	.mmap = btf_sysfs_vmlinux_mmap,}; struct kobject *btf_kobj; static int __init btf_vmlinux_init(void){	bin_attr_btf_vmlinux.private = __start_BTF;	bin_attr_btf_vmlinux.size = __stop_BTF - __start_BTF; 	if (bin_attr_btf_vmlinux.size == 0)		return 0; 	btf_kobj = kobject_create_and_add("btf", kernel_kobj);	if (!btf_kobj)		return -ENOMEM; 	return sysfs_create_bin_file(btf_kobj, &bin_attr_btf_vmlinux);} subsys_initcall(btf_vmlinux_init);