arch/powerpc/kernel/proc_powerpc.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2001 Mike Corrigan & Dave Engebretsen IBM Corporation
   4  */
   5
   6 #include <linux/init.h>
   7 #include <linux/mm.h>
   8 #include <linux/proc_fs.h>
   9 #include <linux/kernel.h>
  10
  11 #include <asm/machdep.h>
  12 #include <asm/vdso_datapage.h>
  13 #include <asm/rtas.h>
  14 #include <linux/uaccess.h>
  15 #include <asm/prom.h>
  16
  17 #ifdef CONFIG_PPC64
  18
  19 static loff_t page_map_seek(struct file *file, loff_t off, int whence)
  20 {
  21         return fixed_size_llseek(file, off, whence, PAGE_SIZE);
  22 }
  23
  24 static ssize_t page_map_read( struct file *file, char __user *buf, size_t nbytes,
  25                               loff_t *ppos)
  26 {
  27         return simple_read_from_buffer(buf, nbytes, ppos,
  28                         PDE_DATA(file_inode(file)), PAGE_SIZE);
  29 }
  30
  31 static int page_map_mmap( struct file *file, struct vm_area_struct *vma )
  32 {
  33         if ((vma->vm_end - vma->vm_start) > PAGE_SIZE)
  34                 return -EINVAL;
  35
  36         remap_pfn_range(vma, vma->vm_start,
  37                         __pa(PDE_DATA(file_inode(file))) >> PAGE_SHIFT,
  38                         PAGE_SIZE, vma->vm_page_prot);
  39         return 0;
  40 }
  41
  42 static const struct proc_ops page_map_proc_ops = {
  43         .proc_lseek     = page_map_seek,
  44         .proc_read      = page_map_read,
  45         .proc_mmap      = page_map_mmap,
  46 };
  47
  48
  49 static int __init proc_ppc64_init(void)
  50 {
  51         struct proc_dir_entry *pde;
  52
  53         pde = proc_create_data("powerpc/systemcfg", S_IFREG | 0444, NULL,
  54                                &page_map_proc_ops, vdso_data);
  55         if (!pde)
  56                 return 1;
  57         proc_set_size(pde, PAGE_SIZE);
  58
  59         return 0;
  60 }
  61 __initcall(proc_ppc64_init);
  62
  63 #endif /* CONFIG_PPC64 */
  64
  65 /*
  66  * Create the ppc64 and ppc64/rtas directories early. This allows us to
  67  * assume that they have been previously created in drivers.
  68  */
  69 static int __init proc_ppc64_create(void)
  70 {
  71         struct proc_dir_entry *root;
  72
  73         root = proc_mkdir("powerpc", NULL);
  74         if (!root)
  75                 return 1;
  76
  77 #ifdef CONFIG_PPC64
  78         if (!proc_symlink("ppc64", NULL, "powerpc"))
  79                 pr_err("Failed to create link /proc/ppc64 -> /proc/powerpc\n");
  80 #endif
  81
  82         if (!of_find_node_by_path("/rtas"))
  83                 return 0;
  84
  85         if (!proc_mkdir("rtas", root))
  86                 return 1;
  87
  88         if (!proc_symlink("rtas", NULL, "powerpc/rtas"))
  89                 return 1;
  90
  91         return 0;
  92 }
  93 core_initcall(proc_ppc64_create);