bootinfo_proc.c (1705B)
1// SPDX-License-Identifier: GPL-2.0 2/* 3 * Based on arch/arm/kernel/atags_proc.c 4 */ 5 6#include <linux/fs.h> 7#include <linux/init.h> 8#include <linux/printk.h> 9#include <linux/proc_fs.h> 10#include <linux/slab.h> 11#include <linux/string.h> 12 13#include <asm/bootinfo.h> 14#include <asm/byteorder.h> 15 16 17static char bootinfo_tmp[1536] __initdata; 18 19static void *bootinfo_copy; 20static size_t bootinfo_size; 21 22static ssize_t bootinfo_read(struct file *file, char __user *buf, 23 size_t count, loff_t *ppos) 24{ 25 return simple_read_from_buffer(buf, count, ppos, bootinfo_copy, 26 bootinfo_size); 27} 28 29static const struct proc_ops bootinfo_proc_ops = { 30 .proc_read = bootinfo_read, 31 .proc_lseek = default_llseek, 32}; 33 34void __init save_bootinfo(const struct bi_record *bi) 35{ 36 const void *start = bi; 37 size_t size = sizeof(bi->tag); 38 39 while (be16_to_cpu(bi->tag) != BI_LAST) { 40 uint16_t n = be16_to_cpu(bi->size); 41 size += n; 42 bi = (struct bi_record *)((unsigned long)bi + n); 43 } 44 45 if (size > sizeof(bootinfo_tmp)) { 46 pr_err("Cannot save %zu bytes of bootinfo\n", size); 47 return; 48 } 49 50 pr_info("Saving %zu bytes of bootinfo\n", size); 51 memcpy(bootinfo_tmp, start, size); 52 bootinfo_size = size; 53} 54 55static int __init init_bootinfo_procfs(void) 56{ 57 /* 58 * This cannot go into save_bootinfo() because kmalloc and proc don't 59 * work yet when it is called. 60 */ 61 struct proc_dir_entry *pde; 62 63 if (!bootinfo_size) 64 return -EINVAL; 65 66 bootinfo_copy = kmemdup(bootinfo_tmp, bootinfo_size, GFP_KERNEL); 67 if (!bootinfo_copy) 68 return -ENOMEM; 69 70 pde = proc_create_data("bootinfo", 0400, NULL, &bootinfo_proc_ops, NULL); 71 if (!pde) { 72 kfree(bootinfo_copy); 73 return -ENOMEM; 74 } 75 76 return 0; 77} 78 79arch_initcall(init_bootinfo_procfs);