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 17 static char bootinfo_tmp[1536] __initdata; 18 19 static void *bootinfo_copy; 20 static size_t bootinfo_size; 21 22 static 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 29 static const struct file_operations bootinfo_fops = { 30 .read = bootinfo_read, 31 .llseek = default_llseek, 32 }; 33 34 void __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 55 static 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_fops, NULL); 71 if (!pde) { 72 kfree(bootinfo_copy); 73 return -ENOMEM; 74 } 75 76 return 0; 77 } 78 79 arch_initcall(init_bootinfo_procfs); 80