1 files changed, 34 insertions, 10 deletions

diff --git a/kernel/bpf/sysfs_btf.c b/kernel/bpf/sysfs_btf.c
index ef6911aee3bb..8e61dc555415 100644
--- a/kernel/bpf/sysfs_btf.c
+++ b/kernel/bpf/sysfs_btf.c
@@ -7,32 +7,56 @@
 #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 __weak __start_BTF[];
-extern char __weak __stop_BTF[];
+extern char __start_BTF[];
+extern char __stop_BTF[];
 
-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)
+static int btf_sysfs_vmlinux_mmap(struct file *filp, struct kobject *kobj,
+				  const struct bin_attribute *attr,
+				  struct vm_area_struct *vma)
 {
-	memcpy(buf, __start_BTF + off, len);
-	return len;
+	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 = btf_vmlinux_read,
+	.read_new = 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 (!__start_BTF || bin_attr_btf_vmlinux.size == 0)
+	if (bin_attr_btf_vmlinux.size == 0)
 		return 0;
 
 	btf_kobj = kobject_create_and_add("btf", kernel_kobj);