blob: 1f3215ac085bca594dc014cf91e23a745a8e1058 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/drivers/char/mem.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 *
Andrew Mortond7d4d842010-03-10 15:21:52 -08006 * Added devfs support.
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 * Jan-11-1998, C. Scott Ananian <cananian@alumni.princeton.edu>
André Goddard Rosaaf901ca2009-11-14 13:09:05 -02008 * Shared /dev/zero mmapping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com>
Linus Torvalds1da177e2005-04-16 15:20:36 -07009 */
10
Linus Torvalds1da177e2005-04-16 15:20:36 -070011#include <linux/mm.h>
12#include <linux/miscdevice.h>
13#include <linux/slab.h>
14#include <linux/vmalloc.h>
15#include <linux/mman.h>
16#include <linux/random.h>
17#include <linux/init.h>
18#include <linux/raw.h>
19#include <linux/tty.h>
20#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#include <linux/ptrace.h>
22#include <linux/device.h>
Vivek Goyal50b1fdb2005-06-25 14:58:23 -070023#include <linux/highmem.h>
24#include <linux/crash_dump.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#include <linux/backing-dev.h>
Vivek Goyal315c2152005-06-25 14:58:24 -070026#include <linux/bootmem.h>
Jens Axboed6b29d72007-06-04 09:59:47 +020027#include <linux/splice.h>
Linus Torvaldsb8a3ad52006-10-13 08:42:10 -070028#include <linux/pfn.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070029
30#include <asm/uaccess.h>
31#include <asm/io.h>
32
33#ifdef CONFIG_IA64
34# include <linux/efi.h>
35#endif
36
Wu Fengguangf2223182009-12-14 17:58:07 -080037static inline unsigned long size_inside_page(unsigned long start,
38 unsigned long size)
39{
40 unsigned long sz;
41
Wu Fengguang7fabadd2009-12-14 17:58:09 -080042 sz = PAGE_SIZE - (start & (PAGE_SIZE - 1));
Wu Fengguangf2223182009-12-14 17:58:07 -080043
Wu Fengguang7fabadd2009-12-14 17:58:09 -080044 return min(sz, size);
Wu Fengguangf2223182009-12-14 17:58:07 -080045}
46
Linus Torvalds1da177e2005-04-16 15:20:36 -070047#ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE
Bjorn Helgaas136939a2006-03-26 01:37:05 -080048static inline int valid_phys_addr_range(unsigned long addr, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -070049{
Bjorn Helgaas136939a2006-03-26 01:37:05 -080050 if (addr + count > __pa(high_memory))
Linus Torvalds1da177e2005-04-16 15:20:36 -070051 return 0;
52
Linus Torvalds1da177e2005-04-16 15:20:36 -070053 return 1;
54}
Bjorn Helgaas80851ef2006-01-08 01:04:13 -080055
Lennert Buytenhek06c67be2006-07-10 04:45:27 -070056static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
Bjorn Helgaas80851ef2006-01-08 01:04:13 -080057{
58 return 1;
59}
Linus Torvalds1da177e2005-04-16 15:20:36 -070060#endif
61
Ingo Molnard0926332008-07-18 00:26:59 +020062#ifdef CONFIG_STRICT_DEVMEM
Venki Pallipadie2beb3e2008-03-06 23:01:47 -080063static inline int range_is_allowed(unsigned long pfn, unsigned long size)
Arjan van de Venae531c22008-04-24 23:40:47 +020064{
Venki Pallipadie2beb3e2008-03-06 23:01:47 -080065 u64 from = ((u64)pfn) << PAGE_SHIFT;
66 u64 to = from + size;
67 u64 cursor = from;
Arjan van de Venae531c22008-04-24 23:40:47 +020068
Venki Pallipadie2beb3e2008-03-06 23:01:47 -080069 while (cursor < to) {
70 if (!devmem_is_allowed(pfn)) {
71 printk(KERN_INFO
72 "Program %s tried to access /dev/mem between %Lx->%Lx.\n",
Arjan van de Venae531c22008-04-24 23:40:47 +020073 current->comm, from, to);
74 return 0;
75 }
Venki Pallipadie2beb3e2008-03-06 23:01:47 -080076 cursor += PAGE_SIZE;
77 pfn++;
Arjan van de Venae531c22008-04-24 23:40:47 +020078 }
79 return 1;
80}
81#else
Venki Pallipadie2beb3e2008-03-06 23:01:47 -080082static inline int range_is_allowed(unsigned long pfn, unsigned long size)
Arjan van de Venae531c22008-04-24 23:40:47 +020083{
84 return 1;
85}
86#endif
87
Andrew Mortond7d4d842010-03-10 15:21:52 -080088void __weak unxlate_dev_mem_ptr(unsigned long phys, void *addr)
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -070089{
90}
91
Linus Torvalds1da177e2005-04-16 15:20:36 -070092/*
Andrew Mortond7d4d842010-03-10 15:21:52 -080093 * This funcion reads the *physical* memory. The f_pos points directly to the
94 * memory location.
Linus Torvalds1da177e2005-04-16 15:20:36 -070095 */
Andrew Mortond7d4d842010-03-10 15:21:52 -080096static ssize_t read_mem(struct file *file, char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 size_t count, loff_t *ppos)
98{
99 unsigned long p = *ppos;
100 ssize_t read, sz;
101 char *ptr;
102
Bjorn Helgaas136939a2006-03-26 01:37:05 -0800103 if (!valid_phys_addr_range(p, count))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 return -EFAULT;
105 read = 0;
106#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
107 /* we don't have page 0 mapped on sparc and m68k.. */
108 if (p < PAGE_SIZE) {
Wu Fengguang7fabadd2009-12-14 17:58:09 -0800109 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 if (sz > 0) {
111 if (clear_user(buf, sz))
112 return -EFAULT;
Andrew Mortond7d4d842010-03-10 15:21:52 -0800113 buf += sz;
114 p += sz;
115 count -= sz;
116 read += sz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 }
118 }
119#endif
120
121 while (count > 0) {
Wu Fengguangfa29e972009-12-14 17:58:08 -0800122 unsigned long remaining;
123
Wu Fengguangf2223182009-12-14 17:58:07 -0800124 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700126 if (!range_is_allowed(p >> PAGE_SHIFT, count))
127 return -EPERM;
128
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 /*
Andrew Mortond7d4d842010-03-10 15:21:52 -0800130 * On ia64 if a page has been mapped somewhere as uncached, then
131 * it must also be accessed uncached by the kernel or data
132 * corruption may occur.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 */
134 ptr = xlate_dev_mem_ptr(p);
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700135 if (!ptr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 return -EFAULT;
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700137
Wu Fengguangfa29e972009-12-14 17:58:08 -0800138 remaining = copy_to_user(buf, ptr, sz);
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700139 unxlate_dev_mem_ptr(p, ptr);
Wu Fengguangfa29e972009-12-14 17:58:08 -0800140 if (remaining)
141 return -EFAULT;
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700142
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 buf += sz;
144 p += sz;
145 count -= sz;
146 read += sz;
147 }
148
149 *ppos += read;
150 return read;
151}
152
Andrew Mortond7d4d842010-03-10 15:21:52 -0800153static ssize_t write_mem(struct file *file, const char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 size_t count, loff_t *ppos)
155{
156 unsigned long p = *ppos;
157 ssize_t written, sz;
158 unsigned long copied;
159 void *ptr;
160
Bjorn Helgaas136939a2006-03-26 01:37:05 -0800161 if (!valid_phys_addr_range(p, count))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 return -EFAULT;
163
164 written = 0;
165
166#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
167 /* we don't have page 0 mapped on sparc and m68k.. */
168 if (p < PAGE_SIZE) {
Wu Fengguang7fabadd2009-12-14 17:58:09 -0800169 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 /* Hmm. Do something? */
171 buf += sz;
172 p += sz;
173 count -= sz;
174 written += sz;
175 }
176#endif
177
178 while (count > 0) {
Wu Fengguangf2223182009-12-14 17:58:07 -0800179 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700181 if (!range_is_allowed(p >> PAGE_SHIFT, sz))
182 return -EPERM;
183
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 /*
Andrew Mortond7d4d842010-03-10 15:21:52 -0800185 * On ia64 if a page has been mapped somewhere as uncached, then
186 * it must also be accessed uncached by the kernel or data
187 * corruption may occur.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 */
189 ptr = xlate_dev_mem_ptr(p);
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700190 if (!ptr) {
Jan Beulichc654d602006-03-25 03:07:31 -0800191 if (written)
192 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 return -EFAULT;
194 }
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700195
196 copied = copy_from_user(ptr, buf, sz);
Wu Fengguangfa29e972009-12-14 17:58:08 -0800197 unxlate_dev_mem_ptr(p, ptr);
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700198 if (copied) {
199 written += sz - copied;
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700200 if (written)
201 break;
202 return -EFAULT;
203 }
204
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205 buf += sz;
206 p += sz;
207 count -= sz;
208 written += sz;
209 }
210
211 *ppos += written;
212 return written;
213}
214
Andrew Mortond7d4d842010-03-10 15:21:52 -0800215int __weak phys_mem_access_prot_allowed(struct file *file,
venkatesh.pallipadi@intel.comf0970c12008-03-18 17:00:20 -0700216 unsigned long pfn, unsigned long size, pgprot_t *vma_prot)
217{
218 return 1;
219}
220
Bjorn Helgaas44ac8412006-01-08 01:04:10 -0800221#ifndef __HAVE_PHYS_MEM_ACCESS_PROT
Andrew Mortond7d4d842010-03-10 15:21:52 -0800222
223/*
224 * Architectures vary in how they handle caching for addresses
225 * outside of main memory.
226 *
227 */
228static int uncached_access(struct file *file, unsigned long addr)
229{
230#if defined(CONFIG_IA64)
231 /*
232 * On ia64, we ignore O_DSYNC because we cannot tolerate memory
233 * attribute aliases.
234 */
235 return !(efi_mem_attributes(addr) & EFI_MEMORY_WB);
236#elif defined(CONFIG_MIPS)
237 {
238 extern int __uncached_access(struct file *file,
239 unsigned long addr);
240
241 return __uncached_access(file, addr);
242 }
243#else
244 /*
245 * Accessing memory above the top the kernel knows about or through a
246 * file pointer
247 * that was marked O_DSYNC will be done non-cached.
248 */
249 if (file->f_flags & O_DSYNC)
250 return 1;
251 return addr >= __pa(high_memory);
252#endif
253}
254
Bjorn Helgaas44ac8412006-01-08 01:04:10 -0800255static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
256 unsigned long size, pgprot_t vma_prot)
257{
258#ifdef pgprot_noncached
259 unsigned long offset = pfn << PAGE_SHIFT;
260
261 if (uncached_access(file, offset))
262 return pgprot_noncached(vma_prot);
263#endif
264 return vma_prot;
265}
266#endif
267
David Howells5da61852006-09-27 01:50:16 -0700268#ifndef CONFIG_MMU
269static unsigned long get_unmapped_area_mem(struct file *file,
270 unsigned long addr,
271 unsigned long len,
272 unsigned long pgoff,
273 unsigned long flags)
274{
275 if (!valid_mmap_phys_addr_range(pgoff, len))
276 return (unsigned long) -EINVAL;
Benjamin Herrenschmidt8a932582007-04-16 22:53:16 -0700277 return pgoff << PAGE_SHIFT;
David Howells5da61852006-09-27 01:50:16 -0700278}
279
280/* can't do an in-place private mapping if there's no MMU */
281static inline int private_mapping_ok(struct vm_area_struct *vma)
282{
283 return vma->vm_flags & VM_MAYSHARE;
284}
285#else
286#define get_unmapped_area_mem NULL
287
288static inline int private_mapping_ok(struct vm_area_struct *vma)
289{
290 return 1;
291}
292#endif
293
Alexey Dobriyanf0f37e22009-09-27 22:29:37 +0400294static const struct vm_operations_struct mmap_mem_ops = {
Rik van Riel7ae8ed52008-07-23 21:27:07 -0700295#ifdef CONFIG_HAVE_IOREMAP_PROT
296 .access = generic_access_phys
297#endif
venkatesh.pallipadi@intel.come7f260a2008-03-18 17:00:21 -0700298};
299
Andrew Mortond7d4d842010-03-10 15:21:52 -0800300static int mmap_mem(struct file *file, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301{
Bjorn Helgaas80851ef2006-01-08 01:04:13 -0800302 size_t size = vma->vm_end - vma->vm_start;
303
Lennert Buytenhek06c67be2006-07-10 04:45:27 -0700304 if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size))
Bjorn Helgaas80851ef2006-01-08 01:04:13 -0800305 return -EINVAL;
306
David Howells5da61852006-09-27 01:50:16 -0700307 if (!private_mapping_ok(vma))
308 return -ENOSYS;
309
Venki Pallipadie2beb3e2008-03-06 23:01:47 -0800310 if (!range_is_allowed(vma->vm_pgoff, size))
311 return -EPERM;
312
venkatesh.pallipadi@intel.comf0970c12008-03-18 17:00:20 -0700313 if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size,
314 &vma->vm_page_prot))
315 return -EINVAL;
316
Roland Dreier8b150472005-10-28 17:46:18 -0700317 vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
Bjorn Helgaas80851ef2006-01-08 01:04:13 -0800318 size,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 vma->vm_page_prot);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320
venkatesh.pallipadi@intel.come7f260a2008-03-18 17:00:21 -0700321 vma->vm_ops = &mmap_mem_ops;
322
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */
324 if (remap_pfn_range(vma,
325 vma->vm_start,
326 vma->vm_pgoff,
Bjorn Helgaas80851ef2006-01-08 01:04:13 -0800327 size,
venkatesh.pallipadi@intel.come7f260a2008-03-18 17:00:21 -0700328 vma->vm_page_prot)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329 return -EAGAIN;
venkatesh.pallipadi@intel.come7f260a2008-03-18 17:00:21 -0700330 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 return 0;
332}
333
Arjan van de Venb781ecb2008-04-29 00:58:34 -0700334#ifdef CONFIG_DEVKMEM
Andrew Mortond7d4d842010-03-10 15:21:52 -0800335static int mmap_kmem(struct file *file, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336{
Linus Torvalds4bb82552005-08-13 14:22:59 -0700337 unsigned long pfn;
338
Linus Torvalds6d3154c2007-01-22 08:53:24 -0800339 /* Turn a kernel-virtual address into a physical page frame */
340 pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT;
Linus Torvalds4bb82552005-08-13 14:22:59 -0700341
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 /*
Andrew Mortond7d4d842010-03-10 15:21:52 -0800343 * RED-PEN: on some architectures there is more mapped memory than
344 * available in mem_map which pfn_valid checks for. Perhaps should add a
345 * new macro here.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 *
347 * RED-PEN: vmalloc is not supported right now.
348 */
Linus Torvalds4bb82552005-08-13 14:22:59 -0700349 if (!pfn_valid(pfn))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 return -EIO;
Linus Torvalds4bb82552005-08-13 14:22:59 -0700351
352 vma->vm_pgoff = pfn;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 return mmap_mem(file, vma);
354}
Arjan van de Venb781ecb2008-04-29 00:58:34 -0700355#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700357#ifdef CONFIG_CRASH_DUMP
358/*
359 * Read memory corresponding to the old kernel.
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700360 */
Vivek Goyal315c2152005-06-25 14:58:24 -0700361static ssize_t read_oldmem(struct file *file, char __user *buf,
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700362 size_t count, loff_t *ppos)
363{
Vivek Goyal315c2152005-06-25 14:58:24 -0700364 unsigned long pfn, offset;
365 size_t read = 0, csize;
366 int rc = 0;
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700367
Maneesh Soni72414d32005-06-25 14:58:28 -0700368 while (count) {
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700369 pfn = *ppos / PAGE_SIZE;
Vivek Goyal315c2152005-06-25 14:58:24 -0700370 if (pfn > saved_max_pfn)
371 return read;
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700372
Vivek Goyal315c2152005-06-25 14:58:24 -0700373 offset = (unsigned long)(*ppos % PAGE_SIZE);
374 if (count > PAGE_SIZE - offset)
375 csize = PAGE_SIZE - offset;
376 else
377 csize = count;
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700378
Vivek Goyal315c2152005-06-25 14:58:24 -0700379 rc = copy_oldmem_page(pfn, buf, csize, offset, 1);
380 if (rc < 0)
381 return rc;
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700382 buf += csize;
383 *ppos += csize;
384 read += csize;
385 count -= csize;
386 }
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700387 return read;
388}
389#endif
390
Arjan van de Venb781ecb2008-04-29 00:58:34 -0700391#ifdef CONFIG_DEVKMEM
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392/*
393 * This function reads the *virtual* memory as seen by the kernel.
394 */
Andrew Mortond7d4d842010-03-10 15:21:52 -0800395static ssize_t read_kmem(struct file *file, char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396 size_t count, loff_t *ppos)
397{
398 unsigned long p = *ppos;
399 ssize_t low_count, read, sz;
400 char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800401 int err = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402
403 read = 0;
404 if (p < (unsigned long) high_memory) {
405 low_count = count;
Andrew Mortond7d4d842010-03-10 15:21:52 -0800406 if (count > (unsigned long)high_memory - p)
407 low_count = (unsigned long)high_memory - p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408
409#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
410 /* we don't have page 0 mapped on sparc and m68k.. */
411 if (p < PAGE_SIZE && low_count > 0) {
Wu Fengguang7fabadd2009-12-14 17:58:09 -0800412 sz = size_inside_page(p, low_count);
413 if (clear_user(buf, sz))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 return -EFAULT;
Wu Fengguang7fabadd2009-12-14 17:58:09 -0800415 buf += sz;
416 p += sz;
417 read += sz;
418 low_count -= sz;
419 count -= sz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420 }
421#endif
422 while (low_count > 0) {
Wu Fengguangf2223182009-12-14 17:58:07 -0800423 sz = size_inside_page(p, low_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424
425 /*
426 * On ia64 if a page has been mapped somewhere as
427 * uncached, then it must also be accessed uncached
428 * by the kernel or data corruption may occur
429 */
430 kbuf = xlate_dev_kmem_ptr((char *)p);
431
432 if (copy_to_user(buf, kbuf, sz))
433 return -EFAULT;
434 buf += sz;
435 p += sz;
436 read += sz;
437 low_count -= sz;
438 count -= sz;
439 }
440 }
441
442 if (count > 0) {
443 kbuf = (char *)__get_free_page(GFP_KERNEL);
444 if (!kbuf)
445 return -ENOMEM;
446 while (count > 0) {
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800447 sz = size_inside_page(p, count);
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800448 if (!is_vmalloc_or_module_addr((void *)p)) {
449 err = -ENXIO;
450 break;
451 }
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800452 sz = vread(kbuf, (char *)p, sz);
453 if (!sz)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454 break;
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800455 if (copy_to_user(buf, kbuf, sz)) {
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800456 err = -EFAULT;
457 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458 }
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800459 count -= sz;
460 buf += sz;
461 read += sz;
462 p += sz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463 }
464 free_page((unsigned long)kbuf);
465 }
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800466 *ppos = p;
467 return read ? read : err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468}
469
470
Andrew Mortond7d4d842010-03-10 15:21:52 -0800471static ssize_t do_write_kmem(unsigned long p, const char __user *buf,
472 size_t count, loff_t *ppos)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473{
474 ssize_t written, sz;
475 unsigned long copied;
476
477 written = 0;
478#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
479 /* we don't have page 0 mapped on sparc and m68k.. */
Wu Fengguangee323982009-12-14 17:58:10 -0800480 if (p < PAGE_SIZE) {
481 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700482 /* Hmm. Do something? */
483 buf += sz;
484 p += sz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485 count -= sz;
486 written += sz;
487 }
488#endif
489
490 while (count > 0) {
491 char *ptr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492
Wu Fengguangee323982009-12-14 17:58:10 -0800493 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494
495 /*
Andrew Mortond7d4d842010-03-10 15:21:52 -0800496 * On ia64 if a page has been mapped somewhere as uncached, then
497 * it must also be accessed uncached by the kernel or data
498 * corruption may occur.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 */
Wu Fengguangee323982009-12-14 17:58:10 -0800500 ptr = xlate_dev_kmem_ptr((char *)p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501
502 copied = copy_from_user(ptr, buf, sz);
503 if (copied) {
Jan Beulichc654d602006-03-25 03:07:31 -0800504 written += sz - copied;
505 if (written)
506 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 return -EFAULT;
508 }
509 buf += sz;
510 p += sz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 count -= sz;
512 written += sz;
513 }
514
515 *ppos += written;
516 return written;
517}
518
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519/*
520 * This function writes to the *virtual* memory as seen by the kernel.
521 */
Andrew Mortond7d4d842010-03-10 15:21:52 -0800522static ssize_t write_kmem(struct file *file, const char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 size_t count, loff_t *ppos)
524{
525 unsigned long p = *ppos;
526 ssize_t wrote = 0;
527 ssize_t virtr = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528 char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800529 int err = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530
531 if (p < (unsigned long) high_memory) {
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800532 unsigned long to_write = min_t(unsigned long, count,
533 (unsigned long)high_memory - p);
Wu Fengguangee323982009-12-14 17:58:10 -0800534 wrote = do_write_kmem(p, buf, to_write, ppos);
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800535 if (wrote != to_write)
536 return wrote;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537 p += wrote;
538 buf += wrote;
539 count -= wrote;
540 }
541
542 if (count > 0) {
543 kbuf = (char *)__get_free_page(GFP_KERNEL);
544 if (!kbuf)
545 return wrote ? wrote : -ENOMEM;
546 while (count > 0) {
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800547 unsigned long sz = size_inside_page(p, count);
548 unsigned long n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800550 if (!is_vmalloc_or_module_addr((void *)p)) {
551 err = -ENXIO;
552 break;
553 }
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800554 n = copy_from_user(kbuf, buf, sz);
555 if (n) {
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800556 err = -EFAULT;
557 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558 }
Wu Fengguangc85e9a92010-02-02 13:44:06 -0800559 vwrite(kbuf, (char *)p, sz);
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800560 count -= sz;
561 buf += sz;
562 virtr += sz;
563 p += sz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564 }
565 free_page((unsigned long)kbuf);
566 }
567
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800568 *ppos = p;
569 return virtr + wrote ? : err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570}
Arjan van de Venb781ecb2008-04-29 00:58:34 -0700571#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572
Russell King4f911d62007-05-08 00:28:17 -0700573#ifdef CONFIG_DEVPORT
Andrew Mortond7d4d842010-03-10 15:21:52 -0800574static ssize_t read_port(struct file *file, char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575 size_t count, loff_t *ppos)
576{
577 unsigned long i = *ppos;
578 char __user *tmp = buf;
579
580 if (!access_ok(VERIFY_WRITE, buf, count))
Andrew Mortond7d4d842010-03-10 15:21:52 -0800581 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582 while (count-- > 0 && i < 65536) {
Andrew Mortond7d4d842010-03-10 15:21:52 -0800583 if (__put_user(inb(i), tmp) < 0)
584 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585 i++;
586 tmp++;
587 }
588 *ppos = i;
589 return tmp-buf;
590}
591
Andrew Mortond7d4d842010-03-10 15:21:52 -0800592static ssize_t write_port(struct file *file, const char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 size_t count, loff_t *ppos)
594{
595 unsigned long i = *ppos;
596 const char __user * tmp = buf;
597
Andrew Mortond7d4d842010-03-10 15:21:52 -0800598 if (!access_ok(VERIFY_READ, buf, count))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599 return -EFAULT;
600 while (count-- > 0 && i < 65536) {
601 char c;
Jan Beulichc654d602006-03-25 03:07:31 -0800602 if (__get_user(c, tmp)) {
603 if (tmp > buf)
604 break;
Andrew Mortond7d4d842010-03-10 15:21:52 -0800605 return -EFAULT;
Jan Beulichc654d602006-03-25 03:07:31 -0800606 }
Andrew Mortond7d4d842010-03-10 15:21:52 -0800607 outb(c, i);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608 i++;
609 tmp++;
610 }
611 *ppos = i;
612 return tmp-buf;
613}
614#endif
615
Andrew Mortond7d4d842010-03-10 15:21:52 -0800616static ssize_t read_null(struct file *file, char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617 size_t count, loff_t *ppos)
618{
619 return 0;
620}
621
Andrew Mortond7d4d842010-03-10 15:21:52 -0800622static ssize_t write_null(struct file *file, const char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700623 size_t count, loff_t *ppos)
624{
625 return count;
626}
627
Jens Axboe1ebd32f2006-04-26 14:40:08 +0200628static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf,
629 struct splice_desc *sd)
630{
631 return sd->len;
632}
633
Andrew Mortond7d4d842010-03-10 15:21:52 -0800634static ssize_t splice_write_null(struct pipe_inode_info *pipe, struct file *out,
Jens Axboe1ebd32f2006-04-26 14:40:08 +0200635 loff_t *ppos, size_t len, unsigned int flags)
636{
637 return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null);
638}
639
Andrew Mortond7d4d842010-03-10 15:21:52 -0800640static ssize_t read_zero(struct file *file, char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 size_t count, loff_t *ppos)
642{
Nick Piggin557ed1f2007-10-16 01:24:40 -0700643 size_t written;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644
645 if (!count)
646 return 0;
647
648 if (!access_ok(VERIFY_WRITE, buf, count))
649 return -EFAULT;
650
Nick Piggin557ed1f2007-10-16 01:24:40 -0700651 written = 0;
652 while (count) {
653 unsigned long unwritten;
654 size_t chunk = count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655
Nick Piggin557ed1f2007-10-16 01:24:40 -0700656 if (chunk > PAGE_SIZE)
657 chunk = PAGE_SIZE; /* Just for latency reasons */
Nikanth Karthikesanbb521c52009-09-23 15:57:09 -0700658 unwritten = __clear_user(buf, chunk);
Nick Piggin557ed1f2007-10-16 01:24:40 -0700659 written += chunk - unwritten;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660 if (unwritten)
Nick Piggin557ed1f2007-10-16 01:24:40 -0700661 break;
Linus Torvalds2b838682009-06-09 20:40:25 -0700662 if (signal_pending(current))
663 return written ? written : -ERESTARTSYS;
Nick Piggin557ed1f2007-10-16 01:24:40 -0700664 buf += chunk;
665 count -= chunk;
666 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668 return written ? written : -EFAULT;
669}
670
Andrew Mortond7d4d842010-03-10 15:21:52 -0800671static int mmap_zero(struct file *file, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672{
Nick Piggin557ed1f2007-10-16 01:24:40 -0700673#ifndef CONFIG_MMU
674 return -ENOSYS;
675#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 if (vma->vm_flags & VM_SHARED)
677 return shmem_zero_setup(vma);
Nick Piggin557ed1f2007-10-16 01:24:40 -0700678 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680
Andrew Mortond7d4d842010-03-10 15:21:52 -0800681static ssize_t write_full(struct file *file, const char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682 size_t count, loff_t *ppos)
683{
684 return -ENOSPC;
685}
686
687/*
688 * Special lseek() function for /dev/null and /dev/zero. Most notably, you
689 * can fopen() both devices with "a" now. This was previously impossible.
690 * -- SRB.
691 */
Andrew Mortond7d4d842010-03-10 15:21:52 -0800692static loff_t null_lseek(struct file *file, loff_t offset, int orig)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693{
694 return file->f_pos = 0;
695}
696
697/*
698 * The memory devices use the full 32/64 bits of the offset, and so we cannot
699 * check against negative addresses: they are ok. The return value is weird,
700 * though, in that case (0).
701 *
702 * also note that seeking relative to the "end of file" isn't supported:
703 * it has no meaning, so it returns -EINVAL.
704 */
Andrew Mortond7d4d842010-03-10 15:21:52 -0800705static loff_t memory_lseek(struct file *file, loff_t offset, int orig)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700706{
707 loff_t ret;
708
Josef Sipeka7113a92006-12-08 02:36:55 -0800709 mutex_lock(&file->f_path.dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710 switch (orig) {
Andrew Mortond7d4d842010-03-10 15:21:52 -0800711 case SEEK_CUR:
712 offset += file->f_pos;
713 if ((unsigned long long)offset <
714 (unsigned long long)file->f_pos) {
715 ret = -EOVERFLOW;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716 break;
Andrew Mortond7d4d842010-03-10 15:21:52 -0800717 }
718 case SEEK_SET:
719 /* to avoid userland mistaking f_pos=-9 as -EBADF=-9 */
720 if ((unsigned long long)offset >= ~0xFFFULL) {
721 ret = -EOVERFLOW;
722 break;
723 }
724 file->f_pos = offset;
725 ret = file->f_pos;
726 force_successful_syscall_return();
727 break;
728 default:
729 ret = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 }
Josef Sipeka7113a92006-12-08 02:36:55 -0800731 mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732 return ret;
733}
734
735static int open_port(struct inode * inode, struct file * filp)
736{
737 return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
738}
739
740#define zero_lseek null_lseek
741#define full_lseek null_lseek
742#define write_zero write_null
743#define read_full read_zero
744#define open_mem open_port
745#define open_kmem open_mem
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700746#define open_oldmem open_mem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747
Arjan van de Ven62322d22006-07-03 00:24:21 -0700748static const struct file_operations mem_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700749 .llseek = memory_lseek,
750 .read = read_mem,
751 .write = write_mem,
752 .mmap = mmap_mem,
753 .open = open_mem,
David Howells5da61852006-09-27 01:50:16 -0700754 .get_unmapped_area = get_unmapped_area_mem,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755};
756
Arjan van de Venb781ecb2008-04-29 00:58:34 -0700757#ifdef CONFIG_DEVKMEM
Arjan van de Ven62322d22006-07-03 00:24:21 -0700758static const struct file_operations kmem_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759 .llseek = memory_lseek,
760 .read = read_kmem,
761 .write = write_kmem,
762 .mmap = mmap_kmem,
763 .open = open_kmem,
David Howells5da61852006-09-27 01:50:16 -0700764 .get_unmapped_area = get_unmapped_area_mem,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765};
Arjan van de Venb781ecb2008-04-29 00:58:34 -0700766#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767
Arjan van de Ven62322d22006-07-03 00:24:21 -0700768static const struct file_operations null_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769 .llseek = null_lseek,
770 .read = read_null,
771 .write = write_null,
Jens Axboe1ebd32f2006-04-26 14:40:08 +0200772 .splice_write = splice_write_null,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700773};
774
Russell King4f911d62007-05-08 00:28:17 -0700775#ifdef CONFIG_DEVPORT
Arjan van de Ven62322d22006-07-03 00:24:21 -0700776static const struct file_operations port_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777 .llseek = memory_lseek,
778 .read = read_port,
779 .write = write_port,
780 .open = open_port,
781};
782#endif
783
Arjan van de Ven62322d22006-07-03 00:24:21 -0700784static const struct file_operations zero_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700785 .llseek = zero_lseek,
786 .read = read_zero,
787 .write = write_zero,
788 .mmap = mmap_zero,
789};
790
David Howells5da61852006-09-27 01:50:16 -0700791/*
792 * capabilities for /dev/zero
793 * - permits private mappings, "copies" are taken of the source of zeros
794 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795static struct backing_dev_info zero_bdi = {
Jens Axboed9938312009-06-12 14:45:52 +0200796 .name = "char/mem",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797 .capabilities = BDI_CAP_MAP_COPY,
798};
799
Arjan van de Ven62322d22006-07-03 00:24:21 -0700800static const struct file_operations full_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801 .llseek = full_lseek,
802 .read = read_full,
803 .write = write_full,
804};
805
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700806#ifdef CONFIG_CRASH_DUMP
Arjan van de Ven62322d22006-07-03 00:24:21 -0700807static const struct file_operations oldmem_fops = {
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700808 .read = read_oldmem,
809 .open = open_oldmem,
810};
811#endif
812
Andrew Mortond7d4d842010-03-10 15:21:52 -0800813static ssize_t kmsg_write(struct file *file, const char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814 size_t count, loff_t *ppos)
815{
816 char *tmp;
Guillaume Chazaraincd140a52006-01-08 01:02:43 -0800817 ssize_t ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818
819 tmp = kmalloc(count + 1, GFP_KERNEL);
820 if (tmp == NULL)
821 return -ENOMEM;
822 ret = -EFAULT;
823 if (!copy_from_user(tmp, buf, count)) {
824 tmp[count] = 0;
825 ret = printk("%s", tmp);
Guillaume Chazaraincd140a52006-01-08 01:02:43 -0800826 if (ret > count)
827 /* printk can add a prefix */
828 ret = count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829 }
830 kfree(tmp);
831 return ret;
832}
833
Arjan van de Ven62322d22006-07-03 00:24:21 -0700834static const struct file_operations kmsg_fops = {
Andrew Mortond7d4d842010-03-10 15:21:52 -0800835 .write = kmsg_write,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836};
837
Kay Sievers389e0cb2009-07-04 16:51:29 +0200838static const struct memdev {
839 const char *name;
Kay Sieverse454cea2009-09-18 23:01:12 +0200840 mode_t mode;
Kay Sievers389e0cb2009-07-04 16:51:29 +0200841 const struct file_operations *fops;
842 struct backing_dev_info *dev_info;
843} devlist[] = {
Kay Sieverse454cea2009-09-18 23:01:12 +0200844 [1] = { "mem", 0, &mem_fops, &directly_mappable_cdev_bdi },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700845#ifdef CONFIG_DEVKMEM
Kay Sieverse454cea2009-09-18 23:01:12 +0200846 [2] = { "kmem", 0, &kmem_fops, &directly_mappable_cdev_bdi },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700847#endif
Kay Sieverse454cea2009-09-18 23:01:12 +0200848 [3] = { "null", 0666, &null_fops, NULL },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700849#ifdef CONFIG_DEVPORT
Kay Sieverse454cea2009-09-18 23:01:12 +0200850 [4] = { "port", 0, &port_fops, NULL },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700851#endif
Kay Sieverse454cea2009-09-18 23:01:12 +0200852 [5] = { "zero", 0666, &zero_fops, &zero_bdi },
853 [7] = { "full", 0666, &full_fops, NULL },
854 [8] = { "random", 0666, &random_fops, NULL },
855 [9] = { "urandom", 0666, &urandom_fops, NULL },
856 [11] = { "kmsg", 0, &kmsg_fops, NULL },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700857#ifdef CONFIG_CRASH_DUMP
Kay Sieverse454cea2009-09-18 23:01:12 +0200858 [12] = { "oldmem", 0, &oldmem_fops, NULL },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700859#endif
860};
861
862static int memory_open(struct inode *inode, struct file *filp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700863{
Kay Sievers389e0cb2009-07-04 16:51:29 +0200864 int minor;
865 const struct memdev *dev;
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700866
Kay Sievers389e0cb2009-07-04 16:51:29 +0200867 minor = iminor(inode);
868 if (minor >= ARRAY_SIZE(devlist))
Frederic Weisbecker205153a2009-10-09 20:31:02 +0200869 return -ENXIO;
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700870
Kay Sievers389e0cb2009-07-04 16:51:29 +0200871 dev = &devlist[minor];
872 if (!dev->fops)
Frederic Weisbecker205153a2009-10-09 20:31:02 +0200873 return -ENXIO;
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700874
Kay Sievers389e0cb2009-07-04 16:51:29 +0200875 filp->f_op = dev->fops;
876 if (dev->dev_info)
877 filp->f_mapping->backing_dev_info = dev->dev_info;
878
879 if (dev->fops->open)
Frederic Weisbecker205153a2009-10-09 20:31:02 +0200880 return dev->fops->open(inode, filp);
881
882 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700883}
884
Arjan van de Ven62322d22006-07-03 00:24:21 -0700885static const struct file_operations memory_fops = {
Andrew Mortond7d4d842010-03-10 15:21:52 -0800886 .open = memory_open,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887};
888
Kay Sieverse454cea2009-09-18 23:01:12 +0200889static char *mem_devnode(struct device *dev, mode_t *mode)
890{
891 if (mode && devlist[MINOR(dev->devt)].mode)
892 *mode = devlist[MINOR(dev->devt)].mode;
893 return NULL;
894}
895
gregkh@suse.deca8eca62005-03-23 09:53:09 -0800896static struct class *mem_class;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897
898static int __init chr_dev_init(void)
899{
Kay Sievers389e0cb2009-07-04 16:51:29 +0200900 int minor;
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -0700901 int err;
902
903 err = bdi_init(&zero_bdi);
904 if (err)
905 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906
Andrew Mortond7d4d842010-03-10 15:21:52 -0800907 if (register_chrdev(MEM_MAJOR, "mem", &memory_fops))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700908 printk("unable to get major %d for memory devs\n", MEM_MAJOR);
909
gregkh@suse.deca8eca62005-03-23 09:53:09 -0800910 mem_class = class_create(THIS_MODULE, "mem");
Kay Sieverse454cea2009-09-18 23:01:12 +0200911 mem_class->devnode = mem_devnode;
Kay Sievers389e0cb2009-07-04 16:51:29 +0200912 for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) {
913 if (!devlist[minor].name)
914 continue;
915 device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor),
916 NULL, devlist[minor].name);
917 }
Greg Kroah-Hartmanebf644c2006-07-25 17:13:31 -0700918
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919 return 0;
920}
921
922fs_initcall(chr_dev_init);