| // SPDX-License-Identifier: GPL-2.0 |
| #include <linux/slab.h> |
| #include <linux/proc_fs.h> |
| #include <asm/setup.h> |
| #include <asm/types.h> |
| #include <asm/page.h> |
| |
| struct buffer { |
| size_t size; |
| char data[]; |
| }; |
| |
| static ssize_t atags_read(struct file *file, char __user *buf, |
| size_t count, loff_t *ppos) |
| { |
| struct buffer *b = PDE_DATA(file_inode(file)); |
| return simple_read_from_buffer(buf, count, ppos, b->data, b->size); |
| } |
| |
| static const struct proc_ops atags_proc_ops = { |
| .proc_read = atags_read, |
| .proc_lseek = default_llseek, |
| }; |
| |
| #define BOOT_PARAMS_SIZE 1536 |
| static char __initdata atags_copy[BOOT_PARAMS_SIZE]; |
| |
| void __init save_atags(const struct tag *tags) |
| { |
| memcpy(atags_copy, tags, sizeof(atags_copy)); |
| } |
| |
| static int __init init_atags_procfs(void) |
| { |
| /* |
| * This cannot go into save_atags() because kmalloc and proc don't work |
| * yet when it is called. |
| */ |
| struct proc_dir_entry *tags_entry; |
| struct tag *tag = (struct tag *)atags_copy; |
| struct buffer *b; |
| size_t size; |
| |
| if (tag->hdr.tag != ATAG_CORE) { |
| pr_info("No ATAGs?\n"); |
| return -EINVAL; |
| } |
| |
| for (; tag->hdr.size; tag = tag_next(tag)) |
| ; |
| |
| /* include the terminating ATAG_NONE */ |
| size = (char *)tag - atags_copy + sizeof(struct tag_header); |
| |
| WARN_ON(tag->hdr.tag != ATAG_NONE); |
| |
| b = kmalloc(sizeof(*b) + size, GFP_KERNEL); |
| if (!b) |
| goto nomem; |
| |
| b->size = size; |
| memcpy(b->data, atags_copy, size); |
| |
| tags_entry = proc_create_data("atags", 0400, NULL, &atags_proc_ops, b); |
| if (!tags_entry) |
| goto nomem; |
| |
| return 0; |
| |
| nomem: |
| kfree(b); |
| pr_err("Exporting ATAGs: not enough memory\n"); |
| |
| return -ENOMEM; |
| } |
| arch_initcall(init_atags_procfs); |