blob: 917403fe10da3eb62c0548bb29a2f0d898c8400a [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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024#include <linux/backing-dev.h>
Jens Axboed6b29d72007-06-04 09:59:47 +020025#include <linux/splice.h>
Linus Torvaldsb8a3ad52006-10-13 08:42:10 -070026#include <linux/pfn.h>
Paul Gortmaker66300e62011-07-10 12:14:53 -040027#include <linux/export.h>
Haren Mynenie1612de2012-07-11 15:18:44 +100028#include <linux/io.h>
Kent Overstreeta27bb332013-05-07 16:19:08 -070029#include <linux/aio.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
31#include <asm/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
33#ifdef CONFIG_IA64
34# include <linux/efi.h>
35#endif
36
Haren Mynenie1612de2012-07-11 15:18:44 +100037#define DEVPORT_MINOR 4
38
Wu Fengguangf2223182009-12-14 17:58:07 -080039static inline unsigned long size_inside_page(unsigned long start,
40 unsigned long size)
41{
42 unsigned long sz;
43
Wu Fengguang7fabadd2009-12-14 17:58:09 -080044 sz = PAGE_SIZE - (start & (PAGE_SIZE - 1));
Wu Fengguangf2223182009-12-14 17:58:07 -080045
Wu Fengguang7fabadd2009-12-14 17:58:09 -080046 return min(sz, size);
Wu Fengguangf2223182009-12-14 17:58:07 -080047}
48
Linus Torvalds1da177e2005-04-16 15:20:36 -070049#ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE
Cyril Chemparathy7e6735c2012-09-12 14:05:58 -040050static inline int valid_phys_addr_range(phys_addr_t addr, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -070051{
Changli Gaocfaf346c2011-03-23 16:42:58 -070052 return addr + count <= __pa(high_memory);
Linus Torvalds1da177e2005-04-16 15:20:36 -070053}
Bjorn Helgaas80851ef2006-01-08 01:04:13 -080054
Lennert Buytenhek06c67be2006-07-10 04:45:27 -070055static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
Bjorn Helgaas80851ef2006-01-08 01:04:13 -080056{
57 return 1;
58}
Linus Torvalds1da177e2005-04-16 15:20:36 -070059#endif
60
Ingo Molnard0926332008-07-18 00:26:59 +020061#ifdef CONFIG_STRICT_DEVMEM
Venki Pallipadie2beb3e2008-03-06 23:01:47 -080062static inline int range_is_allowed(unsigned long pfn, unsigned long size)
Arjan van de Venae531c22008-04-24 23:40:47 +020063{
Venki Pallipadie2beb3e2008-03-06 23:01:47 -080064 u64 from = ((u64)pfn) << PAGE_SHIFT;
65 u64 to = from + size;
66 u64 cursor = from;
Arjan van de Venae531c22008-04-24 23:40:47 +020067
Venki Pallipadie2beb3e2008-03-06 23:01:47 -080068 while (cursor < to) {
69 if (!devmem_is_allowed(pfn)) {
70 printk(KERN_INFO
71 "Program %s tried to access /dev/mem between %Lx->%Lx.\n",
Arjan van de Venae531c22008-04-24 23:40:47 +020072 current->comm, from, to);
73 return 0;
74 }
Venki Pallipadie2beb3e2008-03-06 23:01:47 -080075 cursor += PAGE_SIZE;
76 pfn++;
Arjan van de Venae531c22008-04-24 23:40:47 +020077 }
78 return 1;
79}
80#else
Venki Pallipadie2beb3e2008-03-06 23:01:47 -080081static inline int range_is_allowed(unsigned long pfn, unsigned long size)
Arjan van de Venae531c22008-04-24 23:40:47 +020082{
83 return 1;
84}
85#endif
86
Andrew Mortond7d4d842010-03-10 15:21:52 -080087void __weak unxlate_dev_mem_ptr(unsigned long phys, void *addr)
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -070088{
89}
90
Linus Torvalds1da177e2005-04-16 15:20:36 -070091/*
Andrew Mortond7d4d842010-03-10 15:21:52 -080092 * This funcion reads the *physical* memory. The f_pos points directly to the
93 * memory location.
Linus Torvalds1da177e2005-04-16 15:20:36 -070094 */
Andrew Mortond7d4d842010-03-10 15:21:52 -080095static ssize_t read_mem(struct file *file, char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -070096 size_t count, loff_t *ppos)
97{
Cyril Chemparathy7e6735c2012-09-12 14:05:58 -040098 phys_addr_t p = *ppos;
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 ssize_t read, sz;
100 char *ptr;
101
Petr Tesarik08d2d002014-01-30 09:48:02 +0100102 if (p != *ppos)
103 return 0;
104
Bjorn Helgaas136939a2006-03-26 01:37:05 -0800105 if (!valid_phys_addr_range(p, count))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 return -EFAULT;
107 read = 0;
108#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
109 /* we don't have page 0 mapped on sparc and m68k.. */
110 if (p < PAGE_SIZE) {
Wu Fengguang7fabadd2009-12-14 17:58:09 -0800111 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 if (sz > 0) {
113 if (clear_user(buf, sz))
114 return -EFAULT;
Andrew Mortond7d4d842010-03-10 15:21:52 -0800115 buf += sz;
116 p += sz;
117 count -= sz;
118 read += sz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 }
120 }
121#endif
122
123 while (count > 0) {
Wu Fengguangfa29e972009-12-14 17:58:08 -0800124 unsigned long remaining;
125
Wu Fengguangf2223182009-12-14 17:58:07 -0800126 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700128 if (!range_is_allowed(p >> PAGE_SHIFT, count))
129 return -EPERM;
130
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 /*
Andrew Mortond7d4d842010-03-10 15:21:52 -0800132 * On ia64 if a page has been mapped somewhere as uncached, then
133 * it must also be accessed uncached by the kernel or data
134 * corruption may occur.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 */
136 ptr = xlate_dev_mem_ptr(p);
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700137 if (!ptr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 return -EFAULT;
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700139
Wu Fengguangfa29e972009-12-14 17:58:08 -0800140 remaining = copy_to_user(buf, ptr, sz);
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700141 unxlate_dev_mem_ptr(p, ptr);
Wu Fengguangfa29e972009-12-14 17:58:08 -0800142 if (remaining)
143 return -EFAULT;
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700144
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 buf += sz;
146 p += sz;
147 count -= sz;
148 read += sz;
149 }
150
151 *ppos += read;
152 return read;
153}
154
Andrew Mortond7d4d842010-03-10 15:21:52 -0800155static ssize_t write_mem(struct file *file, const char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 size_t count, loff_t *ppos)
157{
Cyril Chemparathy7e6735c2012-09-12 14:05:58 -0400158 phys_addr_t p = *ppos;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159 ssize_t written, sz;
160 unsigned long copied;
161 void *ptr;
162
Petr Tesarik08d2d002014-01-30 09:48:02 +0100163 if (p != *ppos)
164 return -EFBIG;
165
Bjorn Helgaas136939a2006-03-26 01:37:05 -0800166 if (!valid_phys_addr_range(p, count))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 return -EFAULT;
168
169 written = 0;
170
171#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
172 /* we don't have page 0 mapped on sparc and m68k.. */
173 if (p < PAGE_SIZE) {
Wu Fengguang7fabadd2009-12-14 17:58:09 -0800174 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 /* Hmm. Do something? */
176 buf += sz;
177 p += sz;
178 count -= sz;
179 written += sz;
180 }
181#endif
182
183 while (count > 0) {
Wu Fengguangf2223182009-12-14 17:58:07 -0800184 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700186 if (!range_is_allowed(p >> PAGE_SHIFT, sz))
187 return -EPERM;
188
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 /*
Andrew Mortond7d4d842010-03-10 15:21:52 -0800190 * On ia64 if a page has been mapped somewhere as uncached, then
191 * it must also be accessed uncached by the kernel or data
192 * corruption may occur.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 */
194 ptr = xlate_dev_mem_ptr(p);
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700195 if (!ptr) {
Jan Beulichc654d602006-03-25 03:07:31 -0800196 if (written)
197 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 return -EFAULT;
199 }
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700200
201 copied = copy_from_user(ptr, buf, sz);
Wu Fengguangfa29e972009-12-14 17:58:08 -0800202 unxlate_dev_mem_ptr(p, ptr);
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700203 if (copied) {
204 written += sz - copied;
venkatesh.pallipadi@intel.come045fb22008-03-18 17:00:15 -0700205 if (written)
206 break;
207 return -EFAULT;
208 }
209
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210 buf += sz;
211 p += sz;
212 count -= sz;
213 written += sz;
214 }
215
216 *ppos += written;
217 return written;
218}
219
Andrew Mortond7d4d842010-03-10 15:21:52 -0800220int __weak phys_mem_access_prot_allowed(struct file *file,
venkatesh.pallipadi@intel.comf0970c12008-03-18 17:00:20 -0700221 unsigned long pfn, unsigned long size, pgprot_t *vma_prot)
222{
223 return 1;
224}
225
Bjorn Helgaas44ac8412006-01-08 01:04:10 -0800226#ifndef __HAVE_PHYS_MEM_ACCESS_PROT
Andrew Mortond7d4d842010-03-10 15:21:52 -0800227
228/*
229 * Architectures vary in how they handle caching for addresses
230 * outside of main memory.
231 *
232 */
David Howellsea56f412010-04-06 14:35:08 -0700233#ifdef pgprot_noncached
Cyril Chemparathy7e6735c2012-09-12 14:05:58 -0400234static int uncached_access(struct file *file, phys_addr_t addr)
Andrew Mortond7d4d842010-03-10 15:21:52 -0800235{
236#if defined(CONFIG_IA64)
237 /*
238 * On ia64, we ignore O_DSYNC because we cannot tolerate memory
239 * attribute aliases.
240 */
241 return !(efi_mem_attributes(addr) & EFI_MEMORY_WB);
242#elif defined(CONFIG_MIPS)
243 {
244 extern int __uncached_access(struct file *file,
245 unsigned long addr);
246
247 return __uncached_access(file, addr);
248 }
249#else
250 /*
251 * Accessing memory above the top the kernel knows about or through a
252 * file pointer
253 * that was marked O_DSYNC will be done non-cached.
254 */
255 if (file->f_flags & O_DSYNC)
256 return 1;
257 return addr >= __pa(high_memory);
258#endif
259}
David Howellsea56f412010-04-06 14:35:08 -0700260#endif
Andrew Mortond7d4d842010-03-10 15:21:52 -0800261
Bjorn Helgaas44ac8412006-01-08 01:04:10 -0800262static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
263 unsigned long size, pgprot_t vma_prot)
264{
265#ifdef pgprot_noncached
Cyril Chemparathy7e6735c2012-09-12 14:05:58 -0400266 phys_addr_t offset = pfn << PAGE_SHIFT;
Bjorn Helgaas44ac8412006-01-08 01:04:10 -0800267
268 if (uncached_access(file, offset))
269 return pgprot_noncached(vma_prot);
270#endif
271 return vma_prot;
272}
273#endif
274
David Howells5da61852006-09-27 01:50:16 -0700275#ifndef CONFIG_MMU
276static unsigned long get_unmapped_area_mem(struct file *file,
277 unsigned long addr,
278 unsigned long len,
279 unsigned long pgoff,
280 unsigned long flags)
281{
282 if (!valid_mmap_phys_addr_range(pgoff, len))
283 return (unsigned long) -EINVAL;
Benjamin Herrenschmidt8a932582007-04-16 22:53:16 -0700284 return pgoff << PAGE_SHIFT;
David Howells5da61852006-09-27 01:50:16 -0700285}
286
287/* can't do an in-place private mapping if there's no MMU */
288static inline int private_mapping_ok(struct vm_area_struct *vma)
289{
290 return vma->vm_flags & VM_MAYSHARE;
291}
292#else
293#define get_unmapped_area_mem NULL
294
295static inline int private_mapping_ok(struct vm_area_struct *vma)
296{
297 return 1;
298}
299#endif
300
Alexey Dobriyanf0f37e22009-09-27 22:29:37 +0400301static const struct vm_operations_struct mmap_mem_ops = {
Rik van Riel7ae8ed52008-07-23 21:27:07 -0700302#ifdef CONFIG_HAVE_IOREMAP_PROT
303 .access = generic_access_phys
304#endif
venkatesh.pallipadi@intel.come7f260a2008-03-18 17:00:21 -0700305};
306
Andrew Mortond7d4d842010-03-10 15:21:52 -0800307static int mmap_mem(struct file *file, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308{
Bjorn Helgaas80851ef2006-01-08 01:04:13 -0800309 size_t size = vma->vm_end - vma->vm_start;
310
Lennert Buytenhek06c67be2006-07-10 04:45:27 -0700311 if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size))
Bjorn Helgaas80851ef2006-01-08 01:04:13 -0800312 return -EINVAL;
313
David Howells5da61852006-09-27 01:50:16 -0700314 if (!private_mapping_ok(vma))
315 return -ENOSYS;
316
Venki Pallipadie2beb3e2008-03-06 23:01:47 -0800317 if (!range_is_allowed(vma->vm_pgoff, size))
318 return -EPERM;
319
venkatesh.pallipadi@intel.comf0970c12008-03-18 17:00:20 -0700320 if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size,
321 &vma->vm_page_prot))
322 return -EINVAL;
323
Roland Dreier8b150472005-10-28 17:46:18 -0700324 vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
Bjorn Helgaas80851ef2006-01-08 01:04:13 -0800325 size,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 vma->vm_page_prot);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327
venkatesh.pallipadi@intel.come7f260a2008-03-18 17:00:21 -0700328 vma->vm_ops = &mmap_mem_ops;
329
Konstantin Khlebnikov314e51b2012-10-08 16:29:02 -0700330 /* Remap-pfn-range will mark the range VM_IO */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 if (remap_pfn_range(vma,
332 vma->vm_start,
333 vma->vm_pgoff,
Bjorn Helgaas80851ef2006-01-08 01:04:13 -0800334 size,
venkatesh.pallipadi@intel.come7f260a2008-03-18 17:00:21 -0700335 vma->vm_page_prot)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 return -EAGAIN;
venkatesh.pallipadi@intel.come7f260a2008-03-18 17:00:21 -0700337 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 return 0;
339}
340
Arjan van de Venb781ecb2008-04-29 00:58:34 -0700341#ifdef CONFIG_DEVKMEM
Andrew Mortond7d4d842010-03-10 15:21:52 -0800342static int mmap_kmem(struct file *file, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343{
Linus Torvalds4bb82552005-08-13 14:22:59 -0700344 unsigned long pfn;
345
Linus Torvalds6d3154c2007-01-22 08:53:24 -0800346 /* Turn a kernel-virtual address into a physical page frame */
347 pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT;
Linus Torvalds4bb82552005-08-13 14:22:59 -0700348
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 /*
Andrew Mortond7d4d842010-03-10 15:21:52 -0800350 * RED-PEN: on some architectures there is more mapped memory than
351 * available in mem_map which pfn_valid checks for. Perhaps should add a
352 * new macro here.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 *
354 * RED-PEN: vmalloc is not supported right now.
355 */
Linus Torvalds4bb82552005-08-13 14:22:59 -0700356 if (!pfn_valid(pfn))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357 return -EIO;
Linus Torvalds4bb82552005-08-13 14:22:59 -0700358
359 vma->vm_pgoff = pfn;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360 return mmap_mem(file, vma);
361}
Arjan van de Venb781ecb2008-04-29 00:58:34 -0700362#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363
Arjan van de Venb781ecb2008-04-29 00:58:34 -0700364#ifdef CONFIG_DEVKMEM
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365/*
366 * This function reads the *virtual* memory as seen by the kernel.
367 */
Andrew Mortond7d4d842010-03-10 15:21:52 -0800368static ssize_t read_kmem(struct file *file, char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 size_t count, loff_t *ppos)
370{
371 unsigned long p = *ppos;
372 ssize_t low_count, read, sz;
Hans Grob890537b2013-02-06 11:37:20 +0100373 char *kbuf; /* k-addr because vread() takes vmlist_lock rwlock */
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800374 int err = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375
376 read = 0;
377 if (p < (unsigned long) high_memory) {
378 low_count = count;
Andrew Mortond7d4d842010-03-10 15:21:52 -0800379 if (count > (unsigned long)high_memory - p)
380 low_count = (unsigned long)high_memory - p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381
382#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
383 /* we don't have page 0 mapped on sparc and m68k.. */
384 if (p < PAGE_SIZE && low_count > 0) {
Wu Fengguang7fabadd2009-12-14 17:58:09 -0800385 sz = size_inside_page(p, low_count);
386 if (clear_user(buf, sz))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387 return -EFAULT;
Wu Fengguang7fabadd2009-12-14 17:58:09 -0800388 buf += sz;
389 p += sz;
390 read += sz;
391 low_count -= sz;
392 count -= sz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393 }
394#endif
395 while (low_count > 0) {
Wu Fengguangf2223182009-12-14 17:58:07 -0800396 sz = size_inside_page(p, low_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397
398 /*
399 * On ia64 if a page has been mapped somewhere as
400 * uncached, then it must also be accessed uncached
401 * by the kernel or data corruption may occur
402 */
403 kbuf = xlate_dev_kmem_ptr((char *)p);
404
405 if (copy_to_user(buf, kbuf, sz))
406 return -EFAULT;
407 buf += sz;
408 p += sz;
409 read += sz;
410 low_count -= sz;
411 count -= sz;
412 }
413 }
414
415 if (count > 0) {
416 kbuf = (char *)__get_free_page(GFP_KERNEL);
417 if (!kbuf)
418 return -ENOMEM;
419 while (count > 0) {
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800420 sz = size_inside_page(p, count);
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800421 if (!is_vmalloc_or_module_addr((void *)p)) {
422 err = -ENXIO;
423 break;
424 }
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800425 sz = vread(kbuf, (char *)p, sz);
426 if (!sz)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 break;
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800428 if (copy_to_user(buf, kbuf, sz)) {
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800429 err = -EFAULT;
430 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431 }
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800432 count -= sz;
433 buf += sz;
434 read += sz;
435 p += sz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436 }
437 free_page((unsigned long)kbuf);
438 }
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800439 *ppos = p;
440 return read ? read : err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441}
442
443
Andrew Mortond7d4d842010-03-10 15:21:52 -0800444static ssize_t do_write_kmem(unsigned long p, const char __user *buf,
445 size_t count, loff_t *ppos)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446{
447 ssize_t written, sz;
448 unsigned long copied;
449
450 written = 0;
451#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
452 /* we don't have page 0 mapped on sparc and m68k.. */
Wu Fengguangee323982009-12-14 17:58:10 -0800453 if (p < PAGE_SIZE) {
454 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455 /* Hmm. Do something? */
456 buf += sz;
457 p += sz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458 count -= sz;
459 written += sz;
460 }
461#endif
462
463 while (count > 0) {
464 char *ptr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465
Wu Fengguangee323982009-12-14 17:58:10 -0800466 sz = size_inside_page(p, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467
468 /*
Andrew Mortond7d4d842010-03-10 15:21:52 -0800469 * On ia64 if a page has been mapped somewhere as uncached, then
470 * it must also be accessed uncached by the kernel or data
471 * corruption may occur.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 */
Wu Fengguangee323982009-12-14 17:58:10 -0800473 ptr = xlate_dev_kmem_ptr((char *)p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474
475 copied = copy_from_user(ptr, buf, sz);
476 if (copied) {
Jan Beulichc654d602006-03-25 03:07:31 -0800477 written += sz - copied;
478 if (written)
479 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 return -EFAULT;
481 }
482 buf += sz;
483 p += sz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484 count -= sz;
485 written += sz;
486 }
487
488 *ppos += written;
489 return written;
490}
491
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492/*
493 * This function writes to the *virtual* memory as seen by the kernel.
494 */
Andrew Mortond7d4d842010-03-10 15:21:52 -0800495static ssize_t write_kmem(struct file *file, const char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496 size_t count, loff_t *ppos)
497{
498 unsigned long p = *ppos;
499 ssize_t wrote = 0;
500 ssize_t virtr = 0;
Hans Grob890537b2013-02-06 11:37:20 +0100501 char *kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800502 int err = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503
504 if (p < (unsigned long) high_memory) {
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800505 unsigned long to_write = min_t(unsigned long, count,
506 (unsigned long)high_memory - p);
Wu Fengguangee323982009-12-14 17:58:10 -0800507 wrote = do_write_kmem(p, buf, to_write, ppos);
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800508 if (wrote != to_write)
509 return wrote;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 p += wrote;
511 buf += wrote;
512 count -= wrote;
513 }
514
515 if (count > 0) {
516 kbuf = (char *)__get_free_page(GFP_KERNEL);
517 if (!kbuf)
518 return wrote ? wrote : -ENOMEM;
519 while (count > 0) {
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800520 unsigned long sz = size_inside_page(p, count);
521 unsigned long n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800523 if (!is_vmalloc_or_module_addr((void *)p)) {
524 err = -ENXIO;
525 break;
526 }
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800527 n = copy_from_user(kbuf, buf, sz);
528 if (n) {
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800529 err = -EFAULT;
530 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531 }
Wu Fengguangc85e9a92010-02-02 13:44:06 -0800532 vwrite(kbuf, (char *)p, sz);
Wu Fengguang80ad89a2009-12-14 17:58:10 -0800533 count -= sz;
534 buf += sz;
535 virtr += sz;
536 p += sz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537 }
538 free_page((unsigned long)kbuf);
539 }
540
KAMEZAWA Hiroyuki325fda72010-02-02 13:44:05 -0800541 *ppos = p;
542 return virtr + wrote ? : err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543}
Arjan van de Venb781ecb2008-04-29 00:58:34 -0700544#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545
Russell King4f911d62007-05-08 00:28:17 -0700546#ifdef CONFIG_DEVPORT
Andrew Mortond7d4d842010-03-10 15:21:52 -0800547static ssize_t read_port(struct file *file, char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 size_t count, loff_t *ppos)
549{
550 unsigned long i = *ppos;
551 char __user *tmp = buf;
552
553 if (!access_ok(VERIFY_WRITE, buf, count))
Andrew Mortond7d4d842010-03-10 15:21:52 -0800554 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555 while (count-- > 0 && i < 65536) {
Andrew Mortond7d4d842010-03-10 15:21:52 -0800556 if (__put_user(inb(i), tmp) < 0)
557 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558 i++;
559 tmp++;
560 }
561 *ppos = i;
562 return tmp-buf;
563}
564
Andrew Mortond7d4d842010-03-10 15:21:52 -0800565static ssize_t write_port(struct file *file, const char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 size_t count, loff_t *ppos)
567{
568 unsigned long i = *ppos;
Hans Grob890537b2013-02-06 11:37:20 +0100569 const char __user *tmp = buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570
Andrew Mortond7d4d842010-03-10 15:21:52 -0800571 if (!access_ok(VERIFY_READ, buf, count))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572 return -EFAULT;
573 while (count-- > 0 && i < 65536) {
574 char c;
Jan Beulichc654d602006-03-25 03:07:31 -0800575 if (__get_user(c, tmp)) {
576 if (tmp > buf)
577 break;
Andrew Mortond7d4d842010-03-10 15:21:52 -0800578 return -EFAULT;
Jan Beulichc654d602006-03-25 03:07:31 -0800579 }
Andrew Mortond7d4d842010-03-10 15:21:52 -0800580 outb(c, i);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 i++;
582 tmp++;
583 }
584 *ppos = i;
585 return tmp-buf;
586}
587#endif
588
Andrew Mortond7d4d842010-03-10 15:21:52 -0800589static ssize_t read_null(struct file *file, char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 size_t count, loff_t *ppos)
591{
592 return 0;
593}
594
Andrew Mortond7d4d842010-03-10 15:21:52 -0800595static ssize_t write_null(struct file *file, const char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 size_t count, loff_t *ppos)
597{
598 return count;
599}
600
Zach Brown162934d2013-05-07 16:18:27 -0700601static ssize_t aio_read_null(struct kiocb *iocb, const struct iovec *iov,
602 unsigned long nr_segs, loff_t pos)
603{
604 return 0;
605}
606
607static ssize_t aio_write_null(struct kiocb *iocb, const struct iovec *iov,
608 unsigned long nr_segs, loff_t pos)
609{
610 return iov_length(iov, nr_segs);
611}
612
Jens Axboe1ebd32f2006-04-26 14:40:08 +0200613static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf,
614 struct splice_desc *sd)
615{
616 return sd->len;
617}
618
Andrew Mortond7d4d842010-03-10 15:21:52 -0800619static ssize_t splice_write_null(struct pipe_inode_info *pipe, struct file *out,
Jens Axboe1ebd32f2006-04-26 14:40:08 +0200620 loff_t *ppos, size_t len, unsigned int flags)
621{
622 return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null);
623}
624
Andrew Mortond7d4d842010-03-10 15:21:52 -0800625static ssize_t read_zero(struct file *file, char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626 size_t count, loff_t *ppos)
627{
Nick Piggin557ed1f2007-10-16 01:24:40 -0700628 size_t written;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629
630 if (!count)
631 return 0;
632
633 if (!access_ok(VERIFY_WRITE, buf, count))
634 return -EFAULT;
635
Nick Piggin557ed1f2007-10-16 01:24:40 -0700636 written = 0;
637 while (count) {
638 unsigned long unwritten;
639 size_t chunk = count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640
Nick Piggin557ed1f2007-10-16 01:24:40 -0700641 if (chunk > PAGE_SIZE)
642 chunk = PAGE_SIZE; /* Just for latency reasons */
Nikanth Karthikesanbb521c52009-09-23 15:57:09 -0700643 unwritten = __clear_user(buf, chunk);
Nick Piggin557ed1f2007-10-16 01:24:40 -0700644 written += chunk - unwritten;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645 if (unwritten)
Nick Piggin557ed1f2007-10-16 01:24:40 -0700646 break;
Linus Torvalds2b838682009-06-09 20:40:25 -0700647 if (signal_pending(current))
648 return written ? written : -ERESTARTSYS;
Nick Piggin557ed1f2007-10-16 01:24:40 -0700649 buf += chunk;
650 count -= chunk;
651 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653 return written ? written : -EFAULT;
654}
655
Zach Brown162934d2013-05-07 16:18:27 -0700656static ssize_t aio_read_zero(struct kiocb *iocb, const struct iovec *iov,
657 unsigned long nr_segs, loff_t pos)
658{
659 size_t written = 0;
660 unsigned long i;
661 ssize_t ret;
662
663 for (i = 0; i < nr_segs; i++) {
664 ret = read_zero(iocb->ki_filp, iov[i].iov_base, iov[i].iov_len,
665 &pos);
666 if (ret < 0)
667 break;
668 written += ret;
669 }
670
671 return written ? written : -EFAULT;
672}
673
Andrew Mortond7d4d842010-03-10 15:21:52 -0800674static int mmap_zero(struct file *file, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675{
Nick Piggin557ed1f2007-10-16 01:24:40 -0700676#ifndef CONFIG_MMU
677 return -ENOSYS;
678#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679 if (vma->vm_flags & VM_SHARED)
680 return shmem_zero_setup(vma);
Nick Piggin557ed1f2007-10-16 01:24:40 -0700681 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700683
Andrew Mortond7d4d842010-03-10 15:21:52 -0800684static ssize_t write_full(struct file *file, const char __user *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685 size_t count, loff_t *ppos)
686{
687 return -ENOSPC;
688}
689
690/*
691 * Special lseek() function for /dev/null and /dev/zero. Most notably, you
692 * can fopen() both devices with "a" now. This was previously impossible.
693 * -- SRB.
694 */
Andrew Mortond7d4d842010-03-10 15:21:52 -0800695static loff_t null_lseek(struct file *file, loff_t offset, int orig)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696{
697 return file->f_pos = 0;
698}
699
700/*
701 * The memory devices use the full 32/64 bits of the offset, and so we cannot
702 * check against negative addresses: they are ok. The return value is weird,
703 * though, in that case (0).
704 *
705 * also note that seeking relative to the "end of file" isn't supported:
706 * it has no meaning, so it returns -EINVAL.
707 */
Andrew Mortond7d4d842010-03-10 15:21:52 -0800708static loff_t memory_lseek(struct file *file, loff_t offset, int orig)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709{
710 loff_t ret;
711
Al Viro496ad9a2013-01-23 17:07:38 -0500712 mutex_lock(&file_inode(file)->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713 switch (orig) {
Andrew Mortond7d4d842010-03-10 15:21:52 -0800714 case SEEK_CUR:
715 offset += file->f_pos;
Andrew Mortond7d4d842010-03-10 15:21:52 -0800716 case SEEK_SET:
717 /* to avoid userland mistaking f_pos=-9 as -EBADF=-9 */
Rasmus Villemoes71811f32013-06-05 17:09:39 +0000718 if (IS_ERR_VALUE((unsigned long long)offset)) {
Andrew Mortond7d4d842010-03-10 15:21:52 -0800719 ret = -EOVERFLOW;
720 break;
721 }
722 file->f_pos = offset;
723 ret = file->f_pos;
724 force_successful_syscall_return();
725 break;
726 default:
727 ret = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728 }
Al Viro496ad9a2013-01-23 17:07:38 -0500729 mutex_unlock(&file_inode(file)->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 return ret;
731}
732
Hans Grob890537b2013-02-06 11:37:20 +0100733static int open_port(struct inode *inode, struct file *filp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700734{
735 return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
736}
737
738#define zero_lseek null_lseek
739#define full_lseek null_lseek
740#define write_zero write_null
741#define read_full read_zero
Zach Brown162934d2013-05-07 16:18:27 -0700742#define aio_write_zero aio_write_null
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743#define open_mem open_port
744#define open_kmem open_mem
745
Arjan van de Ven62322d22006-07-03 00:24:21 -0700746static const struct file_operations mem_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747 .llseek = memory_lseek,
748 .read = read_mem,
749 .write = write_mem,
750 .mmap = mmap_mem,
751 .open = open_mem,
David Howells5da61852006-09-27 01:50:16 -0700752 .get_unmapped_area = get_unmapped_area_mem,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753};
754
Arjan van de Venb781ecb2008-04-29 00:58:34 -0700755#ifdef CONFIG_DEVKMEM
Arjan van de Ven62322d22006-07-03 00:24:21 -0700756static const struct file_operations kmem_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757 .llseek = memory_lseek,
758 .read = read_kmem,
759 .write = write_kmem,
760 .mmap = mmap_kmem,
761 .open = open_kmem,
David Howells5da61852006-09-27 01:50:16 -0700762 .get_unmapped_area = get_unmapped_area_mem,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763};
Arjan van de Venb781ecb2008-04-29 00:58:34 -0700764#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765
Arjan van de Ven62322d22006-07-03 00:24:21 -0700766static const struct file_operations null_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767 .llseek = null_lseek,
768 .read = read_null,
769 .write = write_null,
Zach Brown162934d2013-05-07 16:18:27 -0700770 .aio_read = aio_read_null,
771 .aio_write = aio_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,
Zach Brown162934d2013-05-07 16:18:27 -0700788 .aio_read = aio_read_zero,
789 .aio_write = aio_write_zero,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790 .mmap = mmap_zero,
791};
792
David Howells5da61852006-09-27 01:50:16 -0700793/*
794 * capabilities for /dev/zero
795 * - permits private mappings, "copies" are taken of the source of zeros
Jan Kara371d2172010-09-21 11:49:01 +0200796 * - no writeback happens
David Howells5da61852006-09-27 01:50:16 -0700797 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700798static struct backing_dev_info zero_bdi = {
Jens Axboed9938312009-06-12 14:45:52 +0200799 .name = "char/mem",
Jan Kara371d2172010-09-21 11:49:01 +0200800 .capabilities = BDI_CAP_MAP_COPY | BDI_CAP_NO_ACCT_AND_WRITEBACK,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801};
802
Arjan van de Ven62322d22006-07-03 00:24:21 -0700803static const struct file_operations full_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804 .llseek = full_lseek,
805 .read = read_full,
806 .write = write_full,
807};
808
Kay Sievers389e0cb2009-07-04 16:51:29 +0200809static const struct memdev {
810 const char *name;
Al Viro2c9ede52011-07-23 20:24:48 -0400811 umode_t mode;
Kay Sievers389e0cb2009-07-04 16:51:29 +0200812 const struct file_operations *fops;
813 struct backing_dev_info *dev_info;
814} devlist[] = {
Kay Sieverse454cea2009-09-18 23:01:12 +0200815 [1] = { "mem", 0, &mem_fops, &directly_mappable_cdev_bdi },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700816#ifdef CONFIG_DEVKMEM
Kay Sieverse454cea2009-09-18 23:01:12 +0200817 [2] = { "kmem", 0, &kmem_fops, &directly_mappable_cdev_bdi },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700818#endif
Kay Sieverse454cea2009-09-18 23:01:12 +0200819 [3] = { "null", 0666, &null_fops, NULL },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700820#ifdef CONFIG_DEVPORT
Kay Sieverse454cea2009-09-18 23:01:12 +0200821 [4] = { "port", 0, &port_fops, NULL },
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700822#endif
Kay Sieverse454cea2009-09-18 23:01:12 +0200823 [5] = { "zero", 0666, &zero_fops, &zero_bdi },
824 [7] = { "full", 0666, &full_fops, NULL },
825 [8] = { "random", 0666, &random_fops, NULL },
826 [9] = { "urandom", 0666, &urandom_fops, NULL },
Kay Sievers7f3a7812012-05-09 01:37:51 +0200827#ifdef CONFIG_PRINTK
Kay Sieverse11fea92012-05-03 02:29:41 +0200828 [11] = { "kmsg", 0644, &kmsg_fops, NULL },
Kay Sievers7f3a7812012-05-09 01:37:51 +0200829#endif
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700830};
831
832static int memory_open(struct inode *inode, struct file *filp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833{
Kay Sievers389e0cb2009-07-04 16:51:29 +0200834 int minor;
835 const struct memdev *dev;
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700836
Kay Sievers389e0cb2009-07-04 16:51:29 +0200837 minor = iminor(inode);
838 if (minor >= ARRAY_SIZE(devlist))
Frederic Weisbecker205153a2009-10-09 20:31:02 +0200839 return -ENXIO;
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700840
Kay Sievers389e0cb2009-07-04 16:51:29 +0200841 dev = &devlist[minor];
842 if (!dev->fops)
Frederic Weisbecker205153a2009-10-09 20:31:02 +0200843 return -ENXIO;
Adriano dos Santos Fernandesd6f47be2009-06-17 16:27:48 -0700844
Kay Sievers389e0cb2009-07-04 16:51:29 +0200845 filp->f_op = dev->fops;
846 if (dev->dev_info)
847 filp->f_mapping->backing_dev_info = dev->dev_info;
848
KAMEZAWA Hiroyuki4a3956c2010-10-01 14:20:22 -0700849 /* Is /dev/mem or /dev/kmem ? */
850 if (dev->dev_info == &directly_mappable_cdev_bdi)
851 filp->f_mode |= FMODE_UNSIGNED_OFFSET;
852
Kay Sievers389e0cb2009-07-04 16:51:29 +0200853 if (dev->fops->open)
Frederic Weisbecker205153a2009-10-09 20:31:02 +0200854 return dev->fops->open(inode, filp);
855
856 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700857}
858
Arjan van de Ven62322d22006-07-03 00:24:21 -0700859static const struct file_operations memory_fops = {
Andrew Mortond7d4d842010-03-10 15:21:52 -0800860 .open = memory_open,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200861 .llseek = noop_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862};
863
Al Viro2c9ede52011-07-23 20:24:48 -0400864static char *mem_devnode(struct device *dev, umode_t *mode)
Kay Sieverse454cea2009-09-18 23:01:12 +0200865{
866 if (mode && devlist[MINOR(dev->devt)].mode)
867 *mode = devlist[MINOR(dev->devt)].mode;
868 return NULL;
869}
870
gregkh@suse.deca8eca62005-03-23 09:53:09 -0800871static struct class *mem_class;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700872
873static int __init chr_dev_init(void)
874{
Kay Sievers389e0cb2009-07-04 16:51:29 +0200875 int minor;
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -0700876 int err;
877
878 err = bdi_init(&zero_bdi);
879 if (err)
880 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881
Andrew Mortond7d4d842010-03-10 15:21:52 -0800882 if (register_chrdev(MEM_MAJOR, "mem", &memory_fops))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700883 printk("unable to get major %d for memory devs\n", MEM_MAJOR);
884
gregkh@suse.deca8eca62005-03-23 09:53:09 -0800885 mem_class = class_create(THIS_MODULE, "mem");
Anton Blanchard6e191f72010-04-06 14:34:55 -0700886 if (IS_ERR(mem_class))
887 return PTR_ERR(mem_class);
888
Kay Sieverse454cea2009-09-18 23:01:12 +0200889 mem_class->devnode = mem_devnode;
Kay Sievers389e0cb2009-07-04 16:51:29 +0200890 for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) {
891 if (!devlist[minor].name)
892 continue;
Haren Mynenie1612de2012-07-11 15:18:44 +1000893
894 /*
Hans Grob890537b2013-02-06 11:37:20 +0100895 * Create /dev/port?
Haren Mynenie1612de2012-07-11 15:18:44 +1000896 */
897 if ((minor == DEVPORT_MINOR) && !arch_has_dev_port())
898 continue;
899
Kay Sievers389e0cb2009-07-04 16:51:29 +0200900 device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor),
901 NULL, devlist[minor].name);
902 }
Greg Kroah-Hartmanebf644c2006-07-25 17:13:31 -0700903
David Howells31d1d482010-08-06 16:34:43 +0100904 return tty_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905}
906
907fs_initcall(chr_dev_init);