blob: 1451790337160fb8c9fd6a5af935dea6b236f4ca [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>
Paul Gortmaker66300e62011-07-10 12:14:53 -040029#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
31#include <asm/uaccess.h>
32#include <asm/io.h>
33
34#ifdef CONFIG_IA64
35# include <linux/efi.h>
36#endif
37
Wu Fengguangf2223182009-12-14 17:58:07 -080038static inline unsigned long size_inside_page(unsigned long start,
39 unsigned long size)
40{
41 unsigned long sz;
42
Wu Fengguang7fabadd2009-12-14 17:58:09 -080043 sz = PAGE_SIZE - (start & (PAGE_SIZE - 1));
Wu Fengguangf2223182009-12-14 17:58:07 -080044
Wu Fengguang7fabadd2009-12-14 17:58:09 -080045 return min(sz, size);
Wu Fengguangf2223182009-12-14 17:58:07 -080046}
47
Linus Torvalds1da177e2005-04-16 15:20:36 -070048#ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE
Bjorn Helgaas136939a2006-03-26 01:37:05 -080049static inline int valid_phys_addr_range(unsigned long addr, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -070050{
Changli Gaocfaf3462011-03-23 16:42:58 -070051 return addr + count <= __pa(high_memory);
Linus Torvalds1da177e2005-04-16 15:20:36 -070052}
Bjorn Helgaas80851ef2006-01-08 01:04:13 -080053
Lennert Buytenhek06c67be2006-07-10 04:45:27 -070054static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
Bjorn Helgaas80851ef2006-01-08 01:04:13 -080055{
56 return 1;
57}
Linus Torvalds1da177e2005-04-16 15:20:36 -070058#endif
59
Ingo Molnard0926332008-07-18 00:26:59 +020060#ifdef CONFIG_STRICT_DEVMEM
Venki Pallipadie2beb3e2008-03-06 23:01:47 -080061static inline int range_is_allowed(unsigned long pfn, unsigned long size)
Arjan van de Venae531c22008-04-24 23:40:47 +020062{
Venki Pallipadie2beb3e2008-03-06 23:01:47 -080063 u64 from = ((u64)pfn) << PAGE_SHIFT;
64 u64 to = from + size;
65 u64 cursor = from;
Arjan van de Venae531c22008-04-24 23:40:47 +020066
Venki Pallipadie2beb3e2008-03-06 23:01:47 -080067 while (cursor < to) {
68 if (!devmem_is_allowed(pfn)) {
69 printk(KERN_INFO
70 "Program %s tried to access /dev/mem between %Lx->%Lx.\n",
Arjan van de Venae531c22008-04-24 23:40:47 +020071 current->comm, from, to);
72 return 0;
73 }
Venki Pallipadie2beb3e2008-03-06 23:01:47 -080074 cursor += PAGE_SIZE;
75 pfn++;
Arjan van de Venae531c22008-04-24 23:40:47 +020076 }
77 return 1;
78}
79#else
Venki Pallipadie2beb3e2008-03-06 23:01:47 -080080static inline int range_is_allowed(unsigned long pfn, unsigned long size)
Arjan van de Venae531c22008-04-24 23:40:47 +020081{
82 return 1;
83}
84#endif
85
Andrew Mortond7d4d842010-03-10 15:21:52 -080086void __weak unxlate_dev_mem_ptr(unsigned long phys, void *addr)
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -070087{
88}
89
Linus Torvalds1da177e2005-04-16 15:20:36 -070090/*
Andrew Mortond7d4d842010-03-10 15:21:52 -080091 * This funcion reads the *physical* memory. The f_pos points directly to the
92 * memory location.
Linus Torvalds1da177e2005-04-16 15:20:36 -070093 */
Andrew Mortond7d4d842010-03-10 15:21:52 -080094static ssize_t read_mem(struct file *file, char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -070095 size_t count, loff_t *ppos)
96{
97 unsigned long p = *ppos;
98 ssize_t read, sz;
99 char *ptr;
100
Bjorn Helgaas136939a2006-03-26 01:37:05 -0800101 if (!valid_phys_addr_range(p, count))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 return -EFAULT;
103 read = 0;
104#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
105 /* we don't have page 0 mapped on sparc and m68k.. */
106 if (p < PAGE_SIZE) {
Wu Fengguang7fabadd2009-12-14 17:58:09 -0800107 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108 if (sz > 0) {
109 if (clear_user(buf, sz))
110 return -EFAULT;
Andrew Mortond7d4d842010-03-10 15:21:52 -0800111 buf += sz;
112 p += sz;
113 count -= sz;
114 read += sz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115 }
116 }
117#endif
118
119 while (count > 0) {
Wu Fengguangfa29e972009-12-14 17:58:08 -0800120 unsigned long remaining;
121
Wu Fengguangf2223182009-12-14 17:58:07 -0800122 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700124 if (!range_is_allowed(p >> PAGE_SHIFT, count))
125 return -EPERM;
126
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127 /*
Andrew Mortond7d4d842010-03-10 15:21:52 -0800128 * On ia64 if a page has been mapped somewhere as uncached, then
129 * it must also be accessed uncached by the kernel or data
130 * corruption may occur.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 */
132 ptr = xlate_dev_mem_ptr(p);
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700133 if (!ptr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134 return -EFAULT;
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700135
Wu Fengguangfa29e972009-12-14 17:58:08 -0800136 remaining = copy_to_user(buf, ptr, sz);
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700137 unxlate_dev_mem_ptr(p, ptr);
Wu Fengguangfa29e972009-12-14 17:58:08 -0800138 if (remaining)
139 return -EFAULT;
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700140
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 buf += sz;
142 p += sz;
143 count -= sz;
144 read += sz;
145 }
146
147 *ppos += read;
148 return read;
149}
150
Andrew Mortond7d4d842010-03-10 15:21:52 -0800151static ssize_t write_mem(struct file *file, const char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 size_t count, loff_t *ppos)
153{
154 unsigned long p = *ppos;
155 ssize_t written, sz;
156 unsigned long copied;
157 void *ptr;
158
Bjorn Helgaas136939a2006-03-26 01:37:05 -0800159 if (!valid_phys_addr_range(p, count))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160 return -EFAULT;
161
162 written = 0;
163
164#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
165 /* we don't have page 0 mapped on sparc and m68k.. */
166 if (p < PAGE_SIZE) {
Wu Fengguang7fabadd2009-12-14 17:58:09 -0800167 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 /* Hmm. Do something? */
169 buf += sz;
170 p += sz;
171 count -= sz;
172 written += sz;
173 }
174#endif
175
176 while (count > 0) {
Wu Fengguangf2223182009-12-14 17:58:07 -0800177 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700179 if (!range_is_allowed(p >> PAGE_SHIFT, sz))
180 return -EPERM;
181
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 /*
Andrew Mortond7d4d842010-03-10 15:21:52 -0800183 * On ia64 if a page has been mapped somewhere as uncached, then
184 * it must also be accessed uncached by the kernel or data
185 * corruption may occur.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 */
187 ptr = xlate_dev_mem_ptr(p);
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700188 if (!ptr) {
Jan Beulichc654d602006-03-25 03:07:31 -0800189 if (written)
190 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 return -EFAULT;
192 }
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700193
194 copied = copy_from_user(ptr, buf, sz);
Wu Fengguangfa29e972009-12-14 17:58:08 -0800195 unxlate_dev_mem_ptr(p, ptr);
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700196 if (copied) {
197 written += sz - copied;
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700198 if (written)
199 break;
200 return -EFAULT;
201 }
202
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 buf += sz;
204 p += sz;
205 count -= sz;
206 written += sz;
207 }
208
209 *ppos += written;
210 return written;
211}
212
Andrew Mortond7d4d842010-03-10 15:21:52 -0800213int __weak phys_mem_access_prot_allowed(struct file *file,
venkatesh.pallipadi@intel.comf0970c12008-03-18 17:00:20 -0700214 unsigned long pfn, unsigned long size, pgprot_t *vma_prot)
215{
216 return 1;
217}
218
Bjorn Helgaas44ac8412006-01-08 01:04:10 -0800219#ifndef __HAVE_PHYS_MEM_ACCESS_PROT
Andrew Mortond7d4d842010-03-10 15:21:52 -0800220
221/*
222 * Architectures vary in how they handle caching for addresses
223 * outside of main memory.
224 *
225 */
David Howellsea56f412010-04-06 14:35:08 -0700226#ifdef pgprot_noncached
Andrew Mortond7d4d842010-03-10 15:21:52 -0800227static int uncached_access(struct file *file, unsigned long addr)
228{
229#if defined(CONFIG_IA64)
230 /*
231 * On ia64, we ignore O_DSYNC because we cannot tolerate memory
232 * attribute aliases.
233 */
234 return !(efi_mem_attributes(addr) & EFI_MEMORY_WB);
235#elif defined(CONFIG_MIPS)
236 {
237 extern int __uncached_access(struct file *file,
238 unsigned long addr);
239
240 return __uncached_access(file, addr);
241 }
242#else
243 /*
244 * Accessing memory above the top the kernel knows about or through a
245 * file pointer
246 * that was marked O_DSYNC will be done non-cached.
247 */
248 if (file->f_flags & O_DSYNC)
249 return 1;
250 return addr >= __pa(high_memory);
251#endif
252}
David Howellsea56f412010-04-06 14:35:08 -0700253#endif
Andrew Mortond7d4d842010-03-10 15:21:52 -0800254
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;
Andrew Mortond7d4d842010-03-10 15:21:52 -0800713 case SEEK_SET:
714 /* to avoid userland mistaking f_pos=-9 as -EBADF=-9 */
715 if ((unsigned long long)offset >= ~0xFFFULL) {
716 ret = -EOVERFLOW;
717 break;
718 }
719 file->f_pos = offset;
720 ret = file->f_pos;
721 force_successful_syscall_return();
722 break;
723 default:
724 ret = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725 }
Josef Sipeka7113a92006-12-08 02:36:55 -0800726 mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727 return ret;
728}
729
730static int open_port(struct inode * inode, struct file * filp)
731{
732 return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
733}
734
735#define zero_lseek null_lseek
736#define full_lseek null_lseek
737#define write_zero write_null
738#define read_full read_zero
739#define open_mem open_port
740#define open_kmem open_mem
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700741#define open_oldmem open_mem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742
Arjan van de Ven62322d22006-07-03 00:24:21 -0700743static const struct file_operations mem_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744 .llseek = memory_lseek,
745 .read = read_mem,
746 .write = write_mem,
747 .mmap = mmap_mem,
748 .open = open_mem,
David Howells5da61852006-09-27 01:50:16 -0700749 .get_unmapped_area = get_unmapped_area_mem,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750};
751
Arjan van de Venb781ecb2008-04-29 00:58:34 -0700752#ifdef CONFIG_DEVKMEM
Arjan van de Ven62322d22006-07-03 00:24:21 -0700753static const struct file_operations kmem_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700754 .llseek = memory_lseek,
755 .read = read_kmem,
756 .write = write_kmem,
757 .mmap = mmap_kmem,
758 .open = open_kmem,
David Howells5da61852006-09-27 01:50:16 -0700759 .get_unmapped_area = get_unmapped_area_mem,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760};
Arjan van de Venb781ecb2008-04-29 00:58:34 -0700761#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762
Arjan van de Ven62322d22006-07-03 00:24:21 -0700763static const struct file_operations null_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764 .llseek = null_lseek,
765 .read = read_null,
766 .write = write_null,
Jens Axboe1ebd32f2006-04-26 14:40:08 +0200767 .splice_write = splice_write_null,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768};
769
Russell King4f911d62007-05-08 00:28:17 -0700770#ifdef CONFIG_DEVPORT
Arjan van de Ven62322d22006-07-03 00:24:21 -0700771static const struct file_operations port_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700772 .llseek = memory_lseek,
773 .read = read_port,
774 .write = write_port,
775 .open = open_port,
776};
777#endif
778
Arjan van de Ven62322d22006-07-03 00:24:21 -0700779static const struct file_operations zero_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780 .llseek = zero_lseek,
781 .read = read_zero,
782 .write = write_zero,
783 .mmap = mmap_zero,
784};
785
David Howells5da61852006-09-27 01:50:16 -0700786/*
787 * capabilities for /dev/zero
788 * - permits private mappings, "copies" are taken of the source of zeros
Jan Kara371d2172010-09-21 11:49:01 +0200789 * - no writeback happens
David Howells5da61852006-09-27 01:50:16 -0700790 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791static struct backing_dev_info zero_bdi = {
Jens Axboed9938312009-06-12 14:45:52 +0200792 .name = "char/mem",
Jan Kara371d2172010-09-21 11:49:01 +0200793 .capabilities = BDI_CAP_MAP_COPY | BDI_CAP_NO_ACCT_AND_WRITEBACK,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700794};
795
Arjan van de Ven62322d22006-07-03 00:24:21 -0700796static const struct file_operations full_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797 .llseek = full_lseek,
798 .read = read_full,
799 .write = write_full,
800};
801
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700802#ifdef CONFIG_CRASH_DUMP
Arjan van de Ven62322d22006-07-03 00:24:21 -0700803static const struct file_operations oldmem_fops = {
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700804 .read = read_oldmem,
805 .open = open_oldmem,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200806 .llseek = default_llseek,
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700807};
808#endif
809
Kay Sievers7e5b58b2011-04-07 04:29:20 +0200810static ssize_t kmsg_writev(struct kiocb *iocb, const struct iovec *iv,
811 unsigned long count, loff_t pos)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700812{
Kay Sievers7e5b58b2011-04-07 04:29:20 +0200813 char *line, *p;
Andrew Morton70a5f522011-04-12 16:13:31 -0700814 int i;
Kay Sievers7e5b58b2011-04-07 04:29:20 +0200815 ssize_t ret = -EFAULT;
Andrew Morton70a5f522011-04-12 16:13:31 -0700816 size_t len = iov_length(iv, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700817
Andrew Morton70a5f522011-04-12 16:13:31 -0700818 line = kmalloc(len + 1, GFP_KERNEL);
Kay Sievers7e5b58b2011-04-07 04:29:20 +0200819 if (line == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820 return -ENOMEM;
Kay Sievers7e5b58b2011-04-07 04:29:20 +0200821
822 /*
823 * copy all vectors into a single string, to ensure we do
824 * not interleave our log line with other printk calls
825 */
Andrew Morton70a5f522011-04-12 16:13:31 -0700826 p = line;
Kay Sievers7e5b58b2011-04-07 04:29:20 +0200827 for (i = 0; i < count; i++) {
828 if (copy_from_user(p, iv[i].iov_base, iv[i].iov_len))
829 goto out;
830 p += iv[i].iov_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700831 }
Kay Sievers7e5b58b2011-04-07 04:29:20 +0200832 p[0] = '\0';
833
834 ret = printk("%s", line);
835 /* printk can add a prefix */
836 if (ret > len)
837 ret = len;
838out:
839 kfree(line);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840 return ret;
841}
842
Arjan van de Ven62322d22006-07-03 00:24:21 -0700843static const struct file_operations kmsg_fops = {
Kay Sievers7e5b58b2011-04-07 04:29:20 +0200844 .aio_write = kmsg_writev,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200845 .llseek = noop_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846};
847
Kay Sievers389e0cb2009-07-04 16:51:29 +0200848static const struct memdev {
849 const char *name;
Kay Sieverse454cea2009-09-18 23:01:12 +0200850 mode_t mode;
Kay Sievers389e0cb2009-07-04 16:51:29 +0200851 const struct file_operations *fops;
852 struct backing_dev_info *dev_info;
853} devlist[] = {
Kay Sieverse454cea2009-09-18 23:01:12 +0200854 [1] = { "mem", 0, &mem_fops, &directly_mappable_cdev_bdi },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700855#ifdef CONFIG_DEVKMEM
Kay Sieverse454cea2009-09-18 23:01:12 +0200856 [2] = { "kmem", 0, &kmem_fops, &directly_mappable_cdev_bdi },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700857#endif
Kay Sieverse454cea2009-09-18 23:01:12 +0200858 [3] = { "null", 0666, &null_fops, NULL },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700859#ifdef CONFIG_DEVPORT
Kay Sieverse454cea2009-09-18 23:01:12 +0200860 [4] = { "port", 0, &port_fops, NULL },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700861#endif
Kay Sieverse454cea2009-09-18 23:01:12 +0200862 [5] = { "zero", 0666, &zero_fops, &zero_bdi },
863 [7] = { "full", 0666, &full_fops, NULL },
864 [8] = { "random", 0666, &random_fops, NULL },
865 [9] = { "urandom", 0666, &urandom_fops, NULL },
866 [11] = { "kmsg", 0, &kmsg_fops, NULL },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700867#ifdef CONFIG_CRASH_DUMP
Kay Sieverse454cea2009-09-18 23:01:12 +0200868 [12] = { "oldmem", 0, &oldmem_fops, NULL },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700869#endif
870};
871
872static int memory_open(struct inode *inode, struct file *filp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873{
Kay Sievers389e0cb2009-07-04 16:51:29 +0200874 int minor;
875 const struct memdev *dev;
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700876
Kay Sievers389e0cb2009-07-04 16:51:29 +0200877 minor = iminor(inode);
878 if (minor >= ARRAY_SIZE(devlist))
Frederic Weisbecker205153a2009-10-09 20:31:02 +0200879 return -ENXIO;
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700880
Kay Sievers389e0cb2009-07-04 16:51:29 +0200881 dev = &devlist[minor];
882 if (!dev->fops)
Frederic Weisbecker205153a2009-10-09 20:31:02 +0200883 return -ENXIO;
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700884
Kay Sievers389e0cb2009-07-04 16:51:29 +0200885 filp->f_op = dev->fops;
886 if (dev->dev_info)
887 filp->f_mapping->backing_dev_info = dev->dev_info;
888
KAMEZAWA Hiroyuki4a3956c2010-10-01 14:20:22 -0700889 /* Is /dev/mem or /dev/kmem ? */
890 if (dev->dev_info == &directly_mappable_cdev_bdi)
891 filp->f_mode |= FMODE_UNSIGNED_OFFSET;
892
Kay Sievers389e0cb2009-07-04 16:51:29 +0200893 if (dev->fops->open)
Frederic Weisbecker205153a2009-10-09 20:31:02 +0200894 return dev->fops->open(inode, filp);
895
896 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897}
898
Arjan van de Ven62322d22006-07-03 00:24:21 -0700899static const struct file_operations memory_fops = {
Andrew Mortond7d4d842010-03-10 15:21:52 -0800900 .open = memory_open,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200901 .llseek = noop_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700902};
903
Kay Sieverse454cea2009-09-18 23:01:12 +0200904static char *mem_devnode(struct device *dev, mode_t *mode)
905{
906 if (mode && devlist[MINOR(dev->devt)].mode)
907 *mode = devlist[MINOR(dev->devt)].mode;
908 return NULL;
909}
910
gregkh@suse.deca8eca62005-03-23 09:53:09 -0800911static struct class *mem_class;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700912
913static int __init chr_dev_init(void)
914{
Kay Sievers389e0cb2009-07-04 16:51:29 +0200915 int minor;
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -0700916 int err;
917
918 err = bdi_init(&zero_bdi);
919 if (err)
920 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700921
Andrew Mortond7d4d842010-03-10 15:21:52 -0800922 if (register_chrdev(MEM_MAJOR, "mem", &memory_fops))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923 printk("unable to get major %d for memory devs\n", MEM_MAJOR);
924
gregkh@suse.deca8eca62005-03-23 09:53:09 -0800925 mem_class = class_create(THIS_MODULE, "mem");
Anton Blanchard6e191f72010-04-06 14:34:55 -0700926 if (IS_ERR(mem_class))
927 return PTR_ERR(mem_class);
928
Kay Sieverse454cea2009-09-18 23:01:12 +0200929 mem_class->devnode = mem_devnode;
Kay Sievers389e0cb2009-07-04 16:51:29 +0200930 for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) {
931 if (!devlist[minor].name)
932 continue;
933 device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor),
934 NULL, devlist[minor].name);
935 }
Greg Kroah-Hartmanebf644c2006-07-25 17:13:31 -0700936
David Howells31d1d482010-08-06 16:34:43 +0100937 return tty_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700938}
939
940fs_initcall(chr_dev_init);