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 
page_map_seek(struct file * file,loff_t off,int whence)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 
page_map_read(struct file * file,char __user * buf,size_t nbytes,loff_t * ppos)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 
page_map_mmap(struct file * file,struct vm_area_struct * vma)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 
proc_ppc64_init(void)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  */
proc_ppc64_create(void)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);
94