blob: 8fc04b4f311f72c802a1df13af7108e3082a1b3f [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{
Changli Gaocfaf346c2011-03-23 16:42:58 -070050 return addr + count <= __pa(high_memory);
Linus Torvalds1da177e2005-04-16 15:20:36 -070051}
Bjorn Helgaas80851ef2006-01-08 01:04:13 -080052
Lennert Buytenhek06c67be2006-07-10 04:45:27 -070053static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
Bjorn Helgaas80851ef2006-01-08 01:04:13 -080054{
55 return 1;
56}
Linus Torvalds1da177e2005-04-16 15:20:36 -070057#endif
58
Ingo Molnard0926332008-07-18 00:26:59 +020059#ifdef CONFIG_STRICT_DEVMEM
Venki Pallipadie2beb3e2008-03-06 23:01:47 -080060static inline int range_is_allowed(unsigned long pfn, unsigned long size)
Arjan van de Venae531c22008-04-24 23:40:47 +020061{
Venki Pallipadie2beb3e2008-03-06 23:01:47 -080062 u64 from = ((u64)pfn) << PAGE_SHIFT;
63 u64 to = from + size;
64 u64 cursor = from;
Arjan van de Venae531c22008-04-24 23:40:47 +020065
Venki Pallipadie2beb3e2008-03-06 23:01:47 -080066 while (cursor < to) {
67 if (!devmem_is_allowed(pfn)) {
68 printk(KERN_INFO
69 "Program %s tried to access /dev/mem between %Lx->%Lx.\n",
Arjan van de Venae531c22008-04-24 23:40:47 +020070 current->comm, from, to);
71 return 0;
72 }
Venki Pallipadie2beb3e2008-03-06 23:01:47 -080073 cursor += PAGE_SIZE;
74 pfn++;
Arjan van de Venae531c22008-04-24 23:40:47 +020075 }
76 return 1;
77}
78#else
Venki Pallipadie2beb3e2008-03-06 23:01:47 -080079static inline int range_is_allowed(unsigned long pfn, unsigned long size)
Arjan van de Venae531c22008-04-24 23:40:47 +020080{
81 return 1;
82}
83#endif
84
Andrew Mortond7d4d842010-03-10 15:21:52 -080085void __weak unxlate_dev_mem_ptr(unsigned long phys, void *addr)
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -070086{
87}
88
Linus Torvalds1da177e2005-04-16 15:20:36 -070089/*
Andrew Mortond7d4d842010-03-10 15:21:52 -080090 * This funcion reads the *physical* memory. The f_pos points directly to the
91 * memory location.
Linus Torvalds1da177e2005-04-16 15:20:36 -070092 */
Andrew Mortond7d4d842010-03-10 15:21:52 -080093static ssize_t read_mem(struct file *file, char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -070094 size_t count, loff_t *ppos)
95{
96 unsigned long p = *ppos;
97 ssize_t read, sz;
98 char *ptr;
99
Bjorn Helgaas136939a2006-03-26 01:37:05 -0800100 if (!valid_phys_addr_range(p, count))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 return -EFAULT;
102 read = 0;
103#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
104 /* we don't have page 0 mapped on sparc and m68k.. */
105 if (p < PAGE_SIZE) {
Wu Fengguang7fabadd2009-12-14 17:58:09 -0800106 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107 if (sz > 0) {
108 if (clear_user(buf, sz))
109 return -EFAULT;
Andrew Mortond7d4d842010-03-10 15:21:52 -0800110 buf += sz;
111 p += sz;
112 count -= sz;
113 read += sz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 }
115 }
116#endif
117
118 while (count > 0) {
Wu Fengguangfa29e972009-12-14 17:58:08 -0800119 unsigned long remaining;
120
Wu Fengguangf2223182009-12-14 17:58:07 -0800121 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700123 if (!range_is_allowed(p >> PAGE_SHIFT, count))
124 return -EPERM;
125
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 /*
Andrew Mortond7d4d842010-03-10 15:21:52 -0800127 * On ia64 if a page has been mapped somewhere as uncached, then
128 * it must also be accessed uncached by the kernel or data
129 * corruption may occur.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 */
131 ptr = xlate_dev_mem_ptr(p);
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700132 if (!ptr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 return -EFAULT;
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700134
Wu Fengguangfa29e972009-12-14 17:58:08 -0800135 remaining = copy_to_user(buf, ptr, sz);
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700136 unxlate_dev_mem_ptr(p, ptr);
Wu Fengguangfa29e972009-12-14 17:58:08 -0800137 if (remaining)
138 return -EFAULT;
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700139
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 buf += sz;
141 p += sz;
142 count -= sz;
143 read += sz;
144 }
145
146 *ppos += read;
147 return read;
148}
149
Andrew Mortond7d4d842010-03-10 15:21:52 -0800150static ssize_t write_mem(struct file *file, const char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151 size_t count, loff_t *ppos)
152{
153 unsigned long p = *ppos;
154 ssize_t written, sz;
155 unsigned long copied;
156 void *ptr;
157
Bjorn Helgaas136939a2006-03-26 01:37:05 -0800158 if (!valid_phys_addr_range(p, count))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159 return -EFAULT;
160
161 written = 0;
162
163#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
164 /* we don't have page 0 mapped on sparc and m68k.. */
165 if (p < PAGE_SIZE) {
Wu Fengguang7fabadd2009-12-14 17:58:09 -0800166 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 /* Hmm. Do something? */
168 buf += sz;
169 p += sz;
170 count -= sz;
171 written += sz;
172 }
173#endif
174
175 while (count > 0) {
Wu Fengguangf2223182009-12-14 17:58:07 -0800176 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700178 if (!range_is_allowed(p >> PAGE_SHIFT, sz))
179 return -EPERM;
180
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 /*
Andrew Mortond7d4d842010-03-10 15:21:52 -0800182 * On ia64 if a page has been mapped somewhere as uncached, then
183 * it must also be accessed uncached by the kernel or data
184 * corruption may occur.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 */
186 ptr = xlate_dev_mem_ptr(p);
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700187 if (!ptr) {
Jan Beulichc654d602006-03-25 03:07:31 -0800188 if (written)
189 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190 return -EFAULT;
191 }
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700192
193 copied = copy_from_user(ptr, buf, sz);
Wu Fengguangfa29e972009-12-14 17:58:08 -0800194 unxlate_dev_mem_ptr(p, ptr);
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700195 if (copied) {
196 written += sz - copied;
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700197 if (written)
198 break;
199 return -EFAULT;
200 }
201
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 buf += sz;
203 p += sz;
204 count -= sz;
205 written += sz;
206 }
207
208 *ppos += written;
209 return written;
210}
211
Andrew Mortond7d4d842010-03-10 15:21:52 -0800212int __weak phys_mem_access_prot_allowed(struct file *file,
venkatesh.pallipadi@intel.comf0970c12008-03-18 17:00:20 -0700213 unsigned long pfn, unsigned long size, pgprot_t *vma_prot)
214{
215 return 1;
216}
217
Bjorn Helgaas44ac8412006-01-08 01:04:10 -0800218#ifndef __HAVE_PHYS_MEM_ACCESS_PROT
Andrew Mortond7d4d842010-03-10 15:21:52 -0800219
220/*
221 * Architectures vary in how they handle caching for addresses
222 * outside of main memory.
223 *
224 */
David Howellsea56f412010-04-06 14:35:08 -0700225#ifdef pgprot_noncached
Andrew Mortond7d4d842010-03-10 15:21:52 -0800226static int uncached_access(struct file *file, unsigned long addr)
227{
228#if defined(CONFIG_IA64)
229 /*
230 * On ia64, we ignore O_DSYNC because we cannot tolerate memory
231 * attribute aliases.
232 */
233 return !(efi_mem_attributes(addr) & EFI_MEMORY_WB);
234#elif defined(CONFIG_MIPS)
235 {
236 extern int __uncached_access(struct file *file,
237 unsigned long addr);
238
239 return __uncached_access(file, addr);
240 }
241#else
242 /*
243 * Accessing memory above the top the kernel knows about or through a
244 * file pointer
245 * that was marked O_DSYNC will be done non-cached.
246 */
247 if (file->f_flags & O_DSYNC)
248 return 1;
249 return addr >= __pa(high_memory);
250#endif
251}
David Howellsea56f412010-04-06 14:35:08 -0700252#endif
Andrew Mortond7d4d842010-03-10 15:21:52 -0800253
Bjorn Helgaas44ac8412006-01-08 01:04:10 -0800254static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
255 unsigned long size, pgprot_t vma_prot)
256{
257#ifdef pgprot_noncached
258 unsigned long offset = pfn << PAGE_SHIFT;
259
260 if (uncached_access(file, offset))
261 return pgprot_noncached(vma_prot);
262#endif
263 return vma_prot;
264}
265#endif
266
David Howells5da61852006-09-27 01:50:16 -0700267#ifndef CONFIG_MMU
268static unsigned long get_unmapped_area_mem(struct file *file,
269 unsigned long addr,
270 unsigned long len,
271 unsigned long pgoff,
272 unsigned long flags)
273{
274 if (!valid_mmap_phys_addr_range(pgoff, len))
275 return (unsigned long) -EINVAL;
Benjamin Herrenschmidt8a932582007-04-16 22:53:16 -0700276 return pgoff << PAGE_SHIFT;
David Howells5da61852006-09-27 01:50:16 -0700277}
278
279/* can't do an in-place private mapping if there's no MMU */
280static inline int private_mapping_ok(struct vm_area_struct *vma)
281{
282 return vma->vm_flags & VM_MAYSHARE;
283}
284#else
285#define get_unmapped_area_mem NULL
286
287static inline int private_mapping_ok(struct vm_area_struct *vma)
288{
289 return 1;
290}
291#endif
292
Alexey Dobriyanf0f37e22009-09-27 22:29:37 +0400293static const struct vm_operations_struct mmap_mem_ops = {
Rik van Riel7ae8ed52008-07-23 21:27:07 -0700294#ifdef CONFIG_HAVE_IOREMAP_PROT
295 .access = generic_access_phys
296#endif
venkatesh.pallipadi@intel.come7f260a2008-03-18 17:00:21 -0700297};
298
Andrew Mortond7d4d842010-03-10 15:21:52 -0800299static int mmap_mem(struct file *file, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300{
Bjorn Helgaas80851ef2006-01-08 01:04:13 -0800301 size_t size = vma->vm_end - vma->vm_start;
302
Lennert Buytenhek06c67be2006-07-10 04:45:27 -0700303 if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size))
Bjorn Helgaas80851ef2006-01-08 01:04:13 -0800304 return -EINVAL;
305
David Howells5da61852006-09-27 01:50:16 -0700306 if (!private_mapping_ok(vma))
307 return -ENOSYS;
308
Venki Pallipadie2beb3e2008-03-06 23:01:47 -0800309 if (!range_is_allowed(vma->vm_pgoff, size))
310 return -EPERM;
311
venkatesh.pallipadi@intel.comf0970c12008-03-18 17:00:20 -0700312 if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size,
313 &vma->vm_page_prot))
314 return -EINVAL;
315
Roland Dreier8b150472005-10-28 17:46:18 -0700316 vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
Bjorn Helgaas80851ef2006-01-08 01:04:13 -0800317 size,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 vma->vm_page_prot);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319
venkatesh.pallipadi@intel.come7f260a2008-03-18 17:00:21 -0700320 vma->vm_ops = &mmap_mem_ops;
321
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */
323 if (remap_pfn_range(vma,
324 vma->vm_start,
325 vma->vm_pgoff,
Bjorn Helgaas80851ef2006-01-08 01:04:13 -0800326 size,
venkatesh.pallipadi@intel.come7f260a2008-03-18 17:00:21 -0700327 vma->vm_page_prot)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328 return -EAGAIN;
venkatesh.pallipadi@intel.come7f260a2008-03-18 17:00:21 -0700329 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 return 0;
331}
332
Arjan van de Venb781ecb2008-04-29 00:58:34 -0700333#ifdef CONFIG_DEVKMEM
Andrew Mortond7d4d842010-03-10 15:21:52 -0800334static int mmap_kmem(struct file *file, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335{
Linus Torvalds4bb82552005-08-13 14:22:59 -0700336 unsigned long pfn;
337
Linus Torvalds6d3154c2007-01-22 08:53:24 -0800338 /* Turn a kernel-virtual address into a physical page frame */
339 pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT;
Linus Torvalds4bb82552005-08-13 14:22:59 -0700340
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341 /*
Andrew Mortond7d4d842010-03-10 15:21:52 -0800342 * RED-PEN: on some architectures there is more mapped memory than
343 * available in mem_map which pfn_valid checks for. Perhaps should add a
344 * new macro here.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 *
346 * RED-PEN: vmalloc is not supported right now.
347 */
Linus Torvalds4bb82552005-08-13 14:22:59 -0700348 if (!pfn_valid(pfn))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 return -EIO;
Linus Torvalds4bb82552005-08-13 14:22:59 -0700350
351 vma->vm_pgoff = pfn;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352 return mmap_mem(file, vma);
353}
Arjan van de Venb781ecb2008-04-29 00:58:34 -0700354#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700356#ifdef CONFIG_CRASH_DUMP
357/*
358 * Read memory corresponding to the old kernel.
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700359 */
Vivek Goyal315c2152005-06-25 14:58:24 -0700360static ssize_t read_oldmem(struct file *file, char __user *buf,
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700361 size_t count, loff_t *ppos)
362{
Vivek Goyal315c2152005-06-25 14:58:24 -0700363 unsigned long pfn, offset;
364 size_t read = 0, csize;
365 int rc = 0;
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700366
Maneesh Soni72414d32005-06-25 14:58:28 -0700367 while (count) {
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700368 pfn = *ppos / PAGE_SIZE;
Vivek Goyal315c2152005-06-25 14:58:24 -0700369 if (pfn > saved_max_pfn)
370 return read;
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700371
Vivek Goyal315c2152005-06-25 14:58:24 -0700372 offset = (unsigned long)(*ppos % PAGE_SIZE);
373 if (count > PAGE_SIZE - offset)
374 csize = PAGE_SIZE - offset;
375 else
376 csize = count;
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700377
Vivek Goyal315c2152005-06-25 14:58:24 -0700378 rc = copy_oldmem_page(pfn, buf, csize, offset, 1);
379 if (rc < 0)
380 return rc;
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700381 buf += csize;
382 *ppos += csize;
383 read += csize;
384 count -= csize;
385 }
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700386 return read;
387}
388#endif
389
Arjan van de Venb781ecb2008-04-29 00:58:34 -0700390#ifdef CONFIG_DEVKMEM
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391/*
392 * This function reads the *virtual* memory as seen by the kernel.
393 */
Andrew Mortond7d4d842010-03-10 15:21:52 -0800394static ssize_t read_kmem(struct file *file, char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395 size_t count, loff_t *ppos)
396{
397 unsigned long p = *ppos;
398 ssize_t low_count, read, sz;
399 char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800400 int err = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401
402 read = 0;
403 if (p < (unsigned long) high_memory) {
404 low_count = count;
Andrew Mortond7d4d842010-03-10 15:21:52 -0800405 if (count > (unsigned long)high_memory - p)
406 low_count = (unsigned long)high_memory - p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407
408#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
409 /* we don't have page 0 mapped on sparc and m68k.. */
410 if (p < PAGE_SIZE && low_count > 0) {
Wu Fengguang7fabadd2009-12-14 17:58:09 -0800411 sz = size_inside_page(p, low_count);
412 if (clear_user(buf, sz))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 return -EFAULT;
Wu Fengguang7fabadd2009-12-14 17:58:09 -0800414 buf += sz;
415 p += sz;
416 read += sz;
417 low_count -= sz;
418 count -= sz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419 }
420#endif
421 while (low_count > 0) {
Wu Fengguangf2223182009-12-14 17:58:07 -0800422 sz = size_inside_page(p, low_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423
424 /*
425 * On ia64 if a page has been mapped somewhere as
426 * uncached, then it must also be accessed uncached
427 * by the kernel or data corruption may occur
428 */
429 kbuf = xlate_dev_kmem_ptr((char *)p);
430
431 if (copy_to_user(buf, kbuf, sz))
432 return -EFAULT;
433 buf += sz;
434 p += sz;
435 read += sz;
436 low_count -= sz;
437 count -= sz;
438 }
439 }
440
441 if (count > 0) {
442 kbuf = (char *)__get_free_page(GFP_KERNEL);
443 if (!kbuf)
444 return -ENOMEM;
445 while (count > 0) {
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800446 sz = size_inside_page(p, count);
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800447 if (!is_vmalloc_or_module_addr((void *)p)) {
448 err = -ENXIO;
449 break;
450 }
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800451 sz = vread(kbuf, (char *)p, sz);
452 if (!sz)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453 break;
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800454 if (copy_to_user(buf, kbuf, sz)) {
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800455 err = -EFAULT;
456 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457 }
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800458 count -= sz;
459 buf += sz;
460 read += sz;
461 p += sz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462 }
463 free_page((unsigned long)kbuf);
464 }
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800465 *ppos = p;
466 return read ? read : err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467}
468
469
Andrew Mortond7d4d842010-03-10 15:21:52 -0800470static ssize_t do_write_kmem(unsigned long p, const char __user *buf,
471 size_t count, loff_t *ppos)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472{
473 ssize_t written, sz;
474 unsigned long copied;
475
476 written = 0;
477#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
478 /* we don't have page 0 mapped on sparc and m68k.. */
Wu Fengguangee323982009-12-14 17:58:10 -0800479 if (p < PAGE_SIZE) {
480 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 /* Hmm. Do something? */
482 buf += sz;
483 p += sz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484 count -= sz;
485 written += sz;
486 }
487#endif
488
489 while (count > 0) {
490 char *ptr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491
Wu Fengguangee323982009-12-14 17:58:10 -0800492 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493
494 /*
Andrew Mortond7d4d842010-03-10 15:21:52 -0800495 * On ia64 if a page has been mapped somewhere as uncached, then
496 * it must also be accessed uncached by the kernel or data
497 * corruption may occur.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498 */
Wu Fengguangee323982009-12-14 17:58:10 -0800499 ptr = xlate_dev_kmem_ptr((char *)p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500
501 copied = copy_from_user(ptr, buf, sz);
502 if (copied) {
Jan Beulichc654d602006-03-25 03:07:31 -0800503 written += sz - copied;
504 if (written)
505 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506 return -EFAULT;
507 }
508 buf += sz;
509 p += sz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 count -= sz;
511 written += sz;
512 }
513
514 *ppos += written;
515 return written;
516}
517
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518/*
519 * This function writes to the *virtual* memory as seen by the kernel.
520 */
Andrew Mortond7d4d842010-03-10 15:21:52 -0800521static ssize_t write_kmem(struct file *file, const char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522 size_t count, loff_t *ppos)
523{
524 unsigned long p = *ppos;
525 ssize_t wrote = 0;
526 ssize_t virtr = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527 char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800528 int err = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529
530 if (p < (unsigned long) high_memory) {
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800531 unsigned long to_write = min_t(unsigned long, count,
532 (unsigned long)high_memory - p);
Wu Fengguangee323982009-12-14 17:58:10 -0800533 wrote = do_write_kmem(p, buf, to_write, ppos);
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800534 if (wrote != to_write)
535 return wrote;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536 p += wrote;
537 buf += wrote;
538 count -= wrote;
539 }
540
541 if (count > 0) {
542 kbuf = (char *)__get_free_page(GFP_KERNEL);
543 if (!kbuf)
544 return wrote ? wrote : -ENOMEM;
545 while (count > 0) {
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800546 unsigned long sz = size_inside_page(p, count);
547 unsigned long n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800549 if (!is_vmalloc_or_module_addr((void *)p)) {
550 err = -ENXIO;
551 break;
552 }
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800553 n = copy_from_user(kbuf, buf, sz);
554 if (n) {
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800555 err = -EFAULT;
556 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557 }
Wu Fengguangc85e9a92010-02-02 13:44:06 -0800558 vwrite(kbuf, (char *)p, sz);
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800559 count -= sz;
560 buf += sz;
561 virtr += sz;
562 p += sz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563 }
564 free_page((unsigned long)kbuf);
565 }
566
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800567 *ppos = p;
568 return virtr + wrote ? : err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569}
Arjan van de Venb781ecb2008-04-29 00:58:34 -0700570#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571
Russell King4f911d62007-05-08 00:28:17 -0700572#ifdef CONFIG_DEVPORT
Andrew Mortond7d4d842010-03-10 15:21:52 -0800573static ssize_t read_port(struct file *file, char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574 size_t count, loff_t *ppos)
575{
576 unsigned long i = *ppos;
577 char __user *tmp = buf;
578
579 if (!access_ok(VERIFY_WRITE, buf, count))
Andrew Mortond7d4d842010-03-10 15:21:52 -0800580 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 while (count-- > 0 && i < 65536) {
Andrew Mortond7d4d842010-03-10 15:21:52 -0800582 if (__put_user(inb(i), tmp) < 0)
583 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584 i++;
585 tmp++;
586 }
587 *ppos = i;
588 return tmp-buf;
589}
590
Andrew Mortond7d4d842010-03-10 15:21:52 -0800591static ssize_t write_port(struct file *file, const char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592 size_t count, loff_t *ppos)
593{
594 unsigned long i = *ppos;
595 const char __user * tmp = buf;
596
Andrew Mortond7d4d842010-03-10 15:21:52 -0800597 if (!access_ok(VERIFY_READ, buf, count))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598 return -EFAULT;
599 while (count-- > 0 && i < 65536) {
600 char c;
Jan Beulichc654d602006-03-25 03:07:31 -0800601 if (__get_user(c, tmp)) {
602 if (tmp > buf)
603 break;
Andrew Mortond7d4d842010-03-10 15:21:52 -0800604 return -EFAULT;
Jan Beulichc654d602006-03-25 03:07:31 -0800605 }
Andrew Mortond7d4d842010-03-10 15:21:52 -0800606 outb(c, i);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607 i++;
608 tmp++;
609 }
610 *ppos = i;
611 return tmp-buf;
612}
613#endif
614
Andrew Mortond7d4d842010-03-10 15:21:52 -0800615static ssize_t read_null(struct file *file, char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 size_t count, loff_t *ppos)
617{
618 return 0;
619}
620
Andrew Mortond7d4d842010-03-10 15:21:52 -0800621static ssize_t write_null(struct file *file, const char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622 size_t count, loff_t *ppos)
623{
624 return count;
625}
626
Jens Axboe1ebd32f2006-04-26 14:40:08 +0200627static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf,
628 struct splice_desc *sd)
629{
630 return sd->len;
631}
632
Andrew Mortond7d4d842010-03-10 15:21:52 -0800633static ssize_t splice_write_null(struct pipe_inode_info *pipe, struct file *out,
Jens Axboe1ebd32f2006-04-26 14:40:08 +0200634 loff_t *ppos, size_t len, unsigned int flags)
635{
636 return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null);
637}
638
Andrew Mortond7d4d842010-03-10 15:21:52 -0800639static ssize_t read_zero(struct file *file, char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640 size_t count, loff_t *ppos)
641{
Nick Piggin557ed1f2007-10-16 01:24:40 -0700642 size_t written;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643
644 if (!count)
645 return 0;
646
647 if (!access_ok(VERIFY_WRITE, buf, count))
648 return -EFAULT;
649
Nick Piggin557ed1f2007-10-16 01:24:40 -0700650 written = 0;
651 while (count) {
652 unsigned long unwritten;
653 size_t chunk = count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654
Nick Piggin557ed1f2007-10-16 01:24:40 -0700655 if (chunk > PAGE_SIZE)
656 chunk = PAGE_SIZE; /* Just for latency reasons */
Nikanth Karthikesanbb521c52009-09-23 15:57:09 -0700657 unwritten = __clear_user(buf, chunk);
Nick Piggin557ed1f2007-10-16 01:24:40 -0700658 written += chunk - unwritten;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659 if (unwritten)
Nick Piggin557ed1f2007-10-16 01:24:40 -0700660 break;
Linus Torvalds2b838682009-06-09 20:40:25 -0700661 if (signal_pending(current))
662 return written ? written : -ERESTARTSYS;
Nick Piggin557ed1f2007-10-16 01:24:40 -0700663 buf += chunk;
664 count -= chunk;
665 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667 return written ? written : -EFAULT;
668}
669
Andrew Mortond7d4d842010-03-10 15:21:52 -0800670static int mmap_zero(struct file *file, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671{
Nick Piggin557ed1f2007-10-16 01:24:40 -0700672#ifndef CONFIG_MMU
673 return -ENOSYS;
674#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675 if (vma->vm_flags & VM_SHARED)
676 return shmem_zero_setup(vma);
Nick Piggin557ed1f2007-10-16 01:24:40 -0700677 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679
Andrew Mortond7d4d842010-03-10 15:21:52 -0800680static ssize_t write_full(struct file *file, const char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681 size_t count, loff_t *ppos)
682{
683 return -ENOSPC;
684}
685
686/*
687 * Special lseek() function for /dev/null and /dev/zero. Most notably, you
688 * can fopen() both devices with "a" now. This was previously impossible.
689 * -- SRB.
690 */
Andrew Mortond7d4d842010-03-10 15:21:52 -0800691static loff_t null_lseek(struct file *file, loff_t offset, int orig)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692{
693 return file->f_pos = 0;
694}
695
696/*
697 * The memory devices use the full 32/64 bits of the offset, and so we cannot
698 * check against negative addresses: they are ok. The return value is weird,
699 * though, in that case (0).
700 *
701 * also note that seeking relative to the "end of file" isn't supported:
702 * it has no meaning, so it returns -EINVAL.
703 */
Andrew Mortond7d4d842010-03-10 15:21:52 -0800704static loff_t memory_lseek(struct file *file, loff_t offset, int orig)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705{
706 loff_t ret;
707
Josef Sipeka7113a92006-12-08 02:36:55 -0800708 mutex_lock(&file->f_path.dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 switch (orig) {
Andrew Mortond7d4d842010-03-10 15:21:52 -0800710 case SEEK_CUR:
711 offset += file->f_pos;
Andrew Mortond7d4d842010-03-10 15:21:52 -0800712 case SEEK_SET:
713 /* to avoid userland mistaking f_pos=-9 as -EBADF=-9 */
714 if ((unsigned long long)offset >= ~0xFFFULL) {
715 ret = -EOVERFLOW;
716 break;
717 }
718 file->f_pos = offset;
719 ret = file->f_pos;
720 force_successful_syscall_return();
721 break;
722 default:
723 ret = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724 }
Josef Sipeka7113a92006-12-08 02:36:55 -0800725 mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726 return ret;
727}
728
729static int open_port(struct inode * inode, struct file * filp)
730{
731 return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
732}
733
734#define zero_lseek null_lseek
735#define full_lseek null_lseek
736#define write_zero write_null
737#define read_full read_zero
738#define open_mem open_port
739#define open_kmem open_mem
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700740#define open_oldmem open_mem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700741
Arjan van de Ven62322d22006-07-03 00:24:21 -0700742static const struct file_operations mem_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743 .llseek = memory_lseek,
744 .read = read_mem,
745 .write = write_mem,
746 .mmap = mmap_mem,
747 .open = open_mem,
David Howells5da61852006-09-27 01:50:16 -0700748 .get_unmapped_area = get_unmapped_area_mem,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700749};
750
Arjan van de Venb781ecb2008-04-29 00:58:34 -0700751#ifdef CONFIG_DEVKMEM
Arjan van de Ven62322d22006-07-03 00:24:21 -0700752static const struct file_operations kmem_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753 .llseek = memory_lseek,
754 .read = read_kmem,
755 .write = write_kmem,
756 .mmap = mmap_kmem,
757 .open = open_kmem,
David Howells5da61852006-09-27 01:50:16 -0700758 .get_unmapped_area = get_unmapped_area_mem,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759};
Arjan van de Venb781ecb2008-04-29 00:58:34 -0700760#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700761
Arjan van de Ven62322d22006-07-03 00:24:21 -0700762static const struct file_operations null_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763 .llseek = null_lseek,
764 .read = read_null,
765 .write = write_null,
Jens Axboe1ebd32f2006-04-26 14:40:08 +0200766 .splice_write = splice_write_null,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767};
768
Russell King4f911d62007-05-08 00:28:17 -0700769#ifdef CONFIG_DEVPORT
Arjan van de Ven62322d22006-07-03 00:24:21 -0700770static const struct file_operations port_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771 .llseek = memory_lseek,
772 .read = read_port,
773 .write = write_port,
774 .open = open_port,
775};
776#endif
777
Arjan van de Ven62322d22006-07-03 00:24:21 -0700778static const struct file_operations zero_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 .llseek = zero_lseek,
780 .read = read_zero,
781 .write = write_zero,
782 .mmap = mmap_zero,
783};
784
David Howells5da61852006-09-27 01:50:16 -0700785/*
786 * capabilities for /dev/zero
787 * - permits private mappings, "copies" are taken of the source of zeros
Jan Kara371d2172010-09-21 11:49:01 +0200788 * - no writeback happens
David Howells5da61852006-09-27 01:50:16 -0700789 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790static struct backing_dev_info zero_bdi = {
Jens Axboed9938312009-06-12 14:45:52 +0200791 .name = "char/mem",
Jan Kara371d2172010-09-21 11:49:01 +0200792 .capabilities = BDI_CAP_MAP_COPY | BDI_CAP_NO_ACCT_AND_WRITEBACK,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793};
794
Arjan van de Ven62322d22006-07-03 00:24:21 -0700795static const struct file_operations full_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700796 .llseek = full_lseek,
797 .read = read_full,
798 .write = write_full,
799};
800
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700801#ifdef CONFIG_CRASH_DUMP
Arjan van de Ven62322d22006-07-03 00:24:21 -0700802static const struct file_operations oldmem_fops = {
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700803 .read = read_oldmem,
804 .open = open_oldmem,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200805 .llseek = default_llseek,
Vivek Goyal50b1fdb2005-06-25 14:58:23 -0700806};
807#endif
808
Kay Sievers7e5b58b2011-04-07 04:29:20 +0200809static ssize_t kmsg_writev(struct kiocb *iocb, const struct iovec *iv,
810 unsigned long count, loff_t pos)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811{
Kay Sievers7e5b58b2011-04-07 04:29:20 +0200812 char *line, *p;
Andrew Morton70a5f522011-04-12 16:13:31 -0700813 int i;
Kay Sievers7e5b58b2011-04-07 04:29:20 +0200814 ssize_t ret = -EFAULT;
Andrew Morton70a5f522011-04-12 16:13:31 -0700815 size_t len = iov_length(iv, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816
Andrew Morton70a5f522011-04-12 16:13:31 -0700817 line = kmalloc(len + 1, GFP_KERNEL);
Kay Sievers7e5b58b2011-04-07 04:29:20 +0200818 if (line == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700819 return -ENOMEM;
Kay Sievers7e5b58b2011-04-07 04:29:20 +0200820
821 /*
822 * copy all vectors into a single string, to ensure we do
823 * not interleave our log line with other printk calls
824 */
Andrew Morton70a5f522011-04-12 16:13:31 -0700825 p = line;
Kay Sievers7e5b58b2011-04-07 04:29:20 +0200826 for (i = 0; i < count; i++) {
827 if (copy_from_user(p, iv[i].iov_base, iv[i].iov_len))
828 goto out;
829 p += iv[i].iov_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830 }
Kay Sievers7e5b58b2011-04-07 04:29:20 +0200831 p[0] = '\0';
832
833 ret = printk("%s", line);
834 /* printk can add a prefix */
835 if (ret > len)
836 ret = len;
837out:
838 kfree(line);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839 return ret;
840}
841
Arjan van de Ven62322d22006-07-03 00:24:21 -0700842static const struct file_operations kmsg_fops = {
Kay Sievers7e5b58b2011-04-07 04:29:20 +0200843 .aio_write = kmsg_writev,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200844 .llseek = noop_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845};
846
Kay Sievers389e0cb2009-07-04 16:51:29 +0200847static const struct memdev {
848 const char *name;
Kay Sieverse454cea2009-09-18 23:01:12 +0200849 mode_t mode;
Kay Sievers389e0cb2009-07-04 16:51:29 +0200850 const struct file_operations *fops;
851 struct backing_dev_info *dev_info;
852} devlist[] = {
Kay Sieverse454cea2009-09-18 23:01:12 +0200853 [1] = { "mem", 0, &mem_fops, &directly_mappable_cdev_bdi },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700854#ifdef CONFIG_DEVKMEM
Kay Sieverse454cea2009-09-18 23:01:12 +0200855 [2] = { "kmem", 0, &kmem_fops, &directly_mappable_cdev_bdi },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700856#endif
Kay Sieverse454cea2009-09-18 23:01:12 +0200857 [3] = { "null", 0666, &null_fops, NULL },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700858#ifdef CONFIG_DEVPORT
Kay Sieverse454cea2009-09-18 23:01:12 +0200859 [4] = { "port", 0, &port_fops, NULL },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700860#endif
Kay Sieverse454cea2009-09-18 23:01:12 +0200861 [5] = { "zero", 0666, &zero_fops, &zero_bdi },
862 [7] = { "full", 0666, &full_fops, NULL },
863 [8] = { "random", 0666, &random_fops, NULL },
864 [9] = { "urandom", 0666, &urandom_fops, NULL },
865 [11] = { "kmsg", 0, &kmsg_fops, NULL },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700866#ifdef CONFIG_CRASH_DUMP
Kay Sieverse454cea2009-09-18 23:01:12 +0200867 [12] = { "oldmem", 0, &oldmem_fops, NULL },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700868#endif
869};
870
871static int memory_open(struct inode *inode, struct file *filp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700872{
Kay Sievers389e0cb2009-07-04 16:51:29 +0200873 int minor;
874 const struct memdev *dev;
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700875
Kay Sievers389e0cb2009-07-04 16:51:29 +0200876 minor = iminor(inode);
877 if (minor >= ARRAY_SIZE(devlist))
Frederic Weisbecker205153a2009-10-09 20:31:02 +0200878 return -ENXIO;
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700879
Kay Sievers389e0cb2009-07-04 16:51:29 +0200880 dev = &devlist[minor];
881 if (!dev->fops)
Frederic Weisbecker205153a2009-10-09 20:31:02 +0200882 return -ENXIO;
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700883
Kay Sievers389e0cb2009-07-04 16:51:29 +0200884 filp->f_op = dev->fops;
885 if (dev->dev_info)
886 filp->f_mapping->backing_dev_info = dev->dev_info;
887
KAMEZAWA Hiroyuki4a3956c2010-10-01 14:20:22 -0700888 /* Is /dev/mem or /dev/kmem ? */
889 if (dev->dev_info == &directly_mappable_cdev_bdi)
890 filp->f_mode |= FMODE_UNSIGNED_OFFSET;
891
Kay Sievers389e0cb2009-07-04 16:51:29 +0200892 if (dev->fops->open)
Frederic Weisbecker205153a2009-10-09 20:31:02 +0200893 return dev->fops->open(inode, filp);
894
895 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896}
897
Arjan van de Ven62322d22006-07-03 00:24:21 -0700898static const struct file_operations memory_fops = {
Andrew Mortond7d4d842010-03-10 15:21:52 -0800899 .open = memory_open,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200900 .llseek = noop_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700901};
902
Kay Sieverse454cea2009-09-18 23:01:12 +0200903static char *mem_devnode(struct device *dev, mode_t *mode)
904{
905 if (mode && devlist[MINOR(dev->devt)].mode)
906 *mode = devlist[MINOR(dev->devt)].mode;
907 return NULL;
908}
909
gregkh@suse.deca8eca62005-03-23 09:53:09 -0800910static struct class *mem_class;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700911
912static int __init chr_dev_init(void)
913{
Kay Sievers389e0cb2009-07-04 16:51:29 +0200914 int minor;
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -0700915 int err;
916
917 err = bdi_init(&zero_bdi);
918 if (err)
919 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700920
Andrew Mortond7d4d842010-03-10 15:21:52 -0800921 if (register_chrdev(MEM_MAJOR, "mem", &memory_fops))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700922 printk("unable to get major %d for memory devs\n", MEM_MAJOR);
923
gregkh@suse.deca8eca62005-03-23 09:53:09 -0800924 mem_class = class_create(THIS_MODULE, "mem");
Anton Blanchard6e191f72010-04-06 14:34:55 -0700925 if (IS_ERR(mem_class))
926 return PTR_ERR(mem_class);
927
Kay Sieverse454cea2009-09-18 23:01:12 +0200928 mem_class->devnode = mem_devnode;
Kay Sievers389e0cb2009-07-04 16:51:29 +0200929 for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) {
930 if (!devlist[minor].name)
931 continue;
932 device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor),
933 NULL, devlist[minor].name);
934 }
Greg Kroah-Hartmanebf644c2006-07-25 17:13:31 -0700935
David Howells31d1d482010-08-06 16:34:43 +0100936 return tty_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937}
938
939fs_initcall(chr_dev_init);