arch/m68k/kernel/bootinfo_proc.c

   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);