ia64/xen-unstable

view linux-2.6-xen-sparse/drivers/char/mem.c @ 13665:140afd7a5462

merge with xen-unstable.hg
author awilliam@xenbuild2.aw
date Sat Jan 27 14:07:19 2007 -0700 (2007-01-27)
parents 3adf00179a63
children 2caed72258e8
line source
1 /*
2 * linux/drivers/char/mem.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 *
6 * Added devfs support.
7 * Jan-11-1998, C. Scott Ananian <cananian@alumni.princeton.edu>
8 * Shared /dev/zero mmaping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com>
9 */
11 #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>
21 #include <linux/smp_lock.h>
22 #include <linux/ptrace.h>
23 #include <linux/device.h>
24 #include <linux/highmem.h>
25 #include <linux/crash_dump.h>
26 #include <linux/backing-dev.h>
27 #include <linux/bootmem.h>
28 #include <linux/pipe_fs_i.h>
30 #include <asm/uaccess.h>
31 #include <asm/io.h>
33 #ifdef CONFIG_IA64
34 # include <linux/efi.h>
35 #endif
37 /*
38 * Architectures vary in how they handle caching for addresses
39 * outside of main memory.
40 *
41 */
42 static inline int uncached_access(struct file *file, unsigned long addr)
43 {
44 #if defined(__i386__)
45 /*
46 * On the PPro and successors, the MTRRs are used to set
47 * memory types for physical addresses outside main memory,
48 * so blindly setting PCD or PWT on those pages is wrong.
49 * For Pentiums and earlier, the surround logic should disable
50 * caching for the high addresses through the KEN pin, but
51 * we maintain the tradition of paranoia in this code.
52 */
53 if (file->f_flags & O_SYNC)
54 return 1;
55 return !( test_bit(X86_FEATURE_MTRR, boot_cpu_data.x86_capability) ||
56 test_bit(X86_FEATURE_K6_MTRR, boot_cpu_data.x86_capability) ||
57 test_bit(X86_FEATURE_CYRIX_ARR, boot_cpu_data.x86_capability) ||
58 test_bit(X86_FEATURE_CENTAUR_MCR, boot_cpu_data.x86_capability) )
59 && addr >= __pa(high_memory);
60 #elif defined(__x86_64__)
61 /*
62 * This is broken because it can generate memory type aliases,
63 * which can cause cache corruptions
64 * But it is only available for root and we have to be bug-to-bug
65 * compatible with i386.
66 */
67 if (file->f_flags & O_SYNC)
68 return 1;
69 /* same behaviour as i386. PAT always set to cached and MTRRs control the
70 caching behaviour.
71 Hopefully a full PAT implementation will fix that soon. */
72 return 0;
73 #elif defined(CONFIG_IA64)
74 /*
75 * On ia64, we ignore O_SYNC because we cannot tolerate memory attribute aliases.
76 */
77 return !(efi_mem_attributes(addr) & EFI_MEMORY_WB);
78 #else
79 /*
80 * Accessing memory above the top the kernel knows about or through a file pointer
81 * that was marked O_SYNC will be done non-cached.
82 */
83 if (file->f_flags & O_SYNC)
84 return 1;
85 return addr >= __pa(high_memory);
86 #endif
87 }
89 #ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE
90 static inline int valid_phys_addr_range(unsigned long addr, size_t count)
91 {
92 if (addr + count > __pa(high_memory))
93 return 0;
95 return 1;
96 }
98 static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
99 {
100 return 1;
101 }
102 #endif
104 #ifndef ARCH_HAS_DEV_MEM
105 /*
106 * This funcion reads the *physical* memory. The f_pos points directly to the
107 * memory location.
108 */
109 static ssize_t read_mem(struct file * file, char __user * buf,
110 size_t count, loff_t *ppos)
111 {
112 unsigned long p = *ppos;
113 ssize_t read, sz;
114 char *ptr;
116 if (!valid_phys_addr_range(p, count))
117 return -EFAULT;
118 read = 0;
119 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
120 /* we don't have page 0 mapped on sparc and m68k.. */
121 if (p < PAGE_SIZE) {
122 sz = PAGE_SIZE - p;
123 if (sz > count)
124 sz = count;
125 if (sz > 0) {
126 if (clear_user(buf, sz))
127 return -EFAULT;
128 buf += sz;
129 p += sz;
130 count -= sz;
131 read += sz;
132 }
133 }
134 #endif
136 while (count > 0) {
137 /*
138 * Handle first page in case it's not aligned
139 */
140 if (-p & (PAGE_SIZE - 1))
141 sz = -p & (PAGE_SIZE - 1);
142 else
143 sz = PAGE_SIZE;
145 sz = min_t(unsigned long, sz, count);
147 /*
148 * On ia64 if a page has been mapped somewhere as
149 * uncached, then it must also be accessed uncached
150 * by the kernel or data corruption may occur
151 */
152 ptr = xlate_dev_mem_ptr(p);
154 if (copy_to_user(buf, ptr, sz))
155 return -EFAULT;
156 buf += sz;
157 p += sz;
158 count -= sz;
159 read += sz;
160 }
162 *ppos += read;
163 return read;
164 }
166 static ssize_t write_mem(struct file * file, const char __user * buf,
167 size_t count, loff_t *ppos)
168 {
169 unsigned long p = *ppos;
170 ssize_t written, sz;
171 unsigned long copied;
172 void *ptr;
174 if (!valid_phys_addr_range(p, count))
175 return -EFAULT;
177 written = 0;
179 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
180 /* we don't have page 0 mapped on sparc and m68k.. */
181 if (p < PAGE_SIZE) {
182 unsigned long sz = PAGE_SIZE - p;
183 if (sz > count)
184 sz = count;
185 /* Hmm. Do something? */
186 buf += sz;
187 p += sz;
188 count -= sz;
189 written += sz;
190 }
191 #endif
193 while (count > 0) {
194 /*
195 * Handle first page in case it's not aligned
196 */
197 if (-p & (PAGE_SIZE - 1))
198 sz = -p & (PAGE_SIZE - 1);
199 else
200 sz = PAGE_SIZE;
202 sz = min_t(unsigned long, sz, count);
204 /*
205 * On ia64 if a page has been mapped somewhere as
206 * uncached, then it must also be accessed uncached
207 * by the kernel or data corruption may occur
208 */
209 ptr = xlate_dev_mem_ptr(p);
211 copied = copy_from_user(ptr, buf, sz);
212 if (copied) {
213 written += sz - copied;
214 if (written)
215 break;
216 return -EFAULT;
217 }
218 buf += sz;
219 p += sz;
220 count -= sz;
221 written += sz;
222 }
224 *ppos += written;
225 return written;
226 }
227 #endif
229 #ifndef __HAVE_PHYS_MEM_ACCESS_PROT
230 static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
231 unsigned long size, pgprot_t vma_prot)
232 {
233 #ifdef pgprot_noncached
234 unsigned long offset = pfn << PAGE_SHIFT;
236 if (uncached_access(file, offset))
237 return pgprot_noncached(vma_prot);
238 #endif
239 return vma_prot;
240 }
241 #endif
243 static int mmap_mem(struct file * file, struct vm_area_struct * vma)
244 {
245 size_t size = vma->vm_end - vma->vm_start;
247 if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size))
248 return -EINVAL;
250 vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
251 size,
252 vma->vm_page_prot);
254 /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */
255 if (remap_pfn_range(vma,
256 vma->vm_start,
257 vma->vm_pgoff,
258 size,
259 vma->vm_page_prot))
260 return -EAGAIN;
261 return 0;
262 }
264 static int mmap_kmem(struct file * file, struct vm_area_struct * vma)
265 {
266 unsigned long pfn;
268 /* Turn a kernel-virtual address into a physical page frame */
269 pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT;
271 /*
272 * RED-PEN: on some architectures there is more mapped memory
273 * than available in mem_map which pfn_valid checks
274 * for. Perhaps should add a new macro here.
275 *
276 * RED-PEN: vmalloc is not supported right now.
277 */
278 if (!pfn_valid(pfn))
279 return -EIO;
281 vma->vm_pgoff = pfn;
282 return mmap_mem(file, vma);
283 }
285 #ifdef CONFIG_CRASH_DUMP
286 /*
287 * Read memory corresponding to the old kernel.
288 */
289 static ssize_t read_oldmem(struct file *file, char __user *buf,
290 size_t count, loff_t *ppos)
291 {
292 unsigned long pfn, offset;
293 size_t read = 0, csize;
294 int rc = 0;
296 while (count) {
297 pfn = *ppos / PAGE_SIZE;
298 if (pfn > saved_max_pfn)
299 return read;
301 offset = (unsigned long)(*ppos % PAGE_SIZE);
302 if (count > PAGE_SIZE - offset)
303 csize = PAGE_SIZE - offset;
304 else
305 csize = count;
307 rc = copy_oldmem_page(pfn, buf, csize, offset, 1);
308 if (rc < 0)
309 return rc;
310 buf += csize;
311 *ppos += csize;
312 read += csize;
313 count -= csize;
314 }
315 return read;
316 }
317 #endif
319 extern long vread(char *buf, char *addr, unsigned long count);
320 extern long vwrite(char *buf, char *addr, unsigned long count);
322 /*
323 * This function reads the *virtual* memory as seen by the kernel.
324 */
325 static ssize_t read_kmem(struct file *file, char __user *buf,
326 size_t count, loff_t *ppos)
327 {
328 unsigned long p = *ppos;
329 ssize_t low_count, read, sz;
330 char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */
332 read = 0;
333 if (p < (unsigned long) high_memory) {
334 low_count = count;
335 if (count > (unsigned long) high_memory - p)
336 low_count = (unsigned long) high_memory - p;
338 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
339 /* we don't have page 0 mapped on sparc and m68k.. */
340 if (p < PAGE_SIZE && low_count > 0) {
341 size_t tmp = PAGE_SIZE - p;
342 if (tmp > low_count) tmp = low_count;
343 if (clear_user(buf, tmp))
344 return -EFAULT;
345 buf += tmp;
346 p += tmp;
347 read += tmp;
348 low_count -= tmp;
349 count -= tmp;
350 }
351 #endif
352 while (low_count > 0) {
353 /*
354 * Handle first page in case it's not aligned
355 */
356 if (-p & (PAGE_SIZE - 1))
357 sz = -p & (PAGE_SIZE - 1);
358 else
359 sz = PAGE_SIZE;
361 sz = min_t(unsigned long, sz, low_count);
363 /*
364 * On ia64 if a page has been mapped somewhere as
365 * uncached, then it must also be accessed uncached
366 * by the kernel or data corruption may occur
367 */
368 kbuf = xlate_dev_kmem_ptr((char *)p);
370 if (copy_to_user(buf, kbuf, sz))
371 return -EFAULT;
372 buf += sz;
373 p += sz;
374 read += sz;
375 low_count -= sz;
376 count -= sz;
377 }
378 }
380 if (count > 0) {
381 kbuf = (char *)__get_free_page(GFP_KERNEL);
382 if (!kbuf)
383 return -ENOMEM;
384 while (count > 0) {
385 int len = count;
387 if (len > PAGE_SIZE)
388 len = PAGE_SIZE;
389 len = vread(kbuf, (char *)p, len);
390 if (!len)
391 break;
392 if (copy_to_user(buf, kbuf, len)) {
393 free_page((unsigned long)kbuf);
394 return -EFAULT;
395 }
396 count -= len;
397 buf += len;
398 read += len;
399 p += len;
400 }
401 free_page((unsigned long)kbuf);
402 }
403 *ppos = p;
404 return read;
405 }
408 static inline ssize_t
409 do_write_kmem(void *p, unsigned long realp, const char __user * buf,
410 size_t count, loff_t *ppos)
411 {
412 ssize_t written, sz;
413 unsigned long copied;
415 written = 0;
416 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
417 /* we don't have page 0 mapped on sparc and m68k.. */
418 if (realp < PAGE_SIZE) {
419 unsigned long sz = PAGE_SIZE - realp;
420 if (sz > count)
421 sz = count;
422 /* Hmm. Do something? */
423 buf += sz;
424 p += sz;
425 realp += sz;
426 count -= sz;
427 written += sz;
428 }
429 #endif
431 while (count > 0) {
432 char *ptr;
433 /*
434 * Handle first page in case it's not aligned
435 */
436 if (-realp & (PAGE_SIZE - 1))
437 sz = -realp & (PAGE_SIZE - 1);
438 else
439 sz = PAGE_SIZE;
441 sz = min_t(unsigned long, sz, count);
443 /*
444 * On ia64 if a page has been mapped somewhere as
445 * uncached, then it must also be accessed uncached
446 * by the kernel or data corruption may occur
447 */
448 ptr = xlate_dev_kmem_ptr(p);
450 copied = copy_from_user(ptr, buf, sz);
451 if (copied) {
452 written += sz - copied;
453 if (written)
454 break;
455 return -EFAULT;
456 }
457 buf += sz;
458 p += sz;
459 realp += sz;
460 count -= sz;
461 written += sz;
462 }
464 *ppos += written;
465 return written;
466 }
469 /*
470 * This function writes to the *virtual* memory as seen by the kernel.
471 */
472 static ssize_t write_kmem(struct file * file, const char __user * buf,
473 size_t count, loff_t *ppos)
474 {
475 unsigned long p = *ppos;
476 ssize_t wrote = 0;
477 ssize_t virtr = 0;
478 ssize_t written;
479 char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */
481 if (p < (unsigned long) high_memory) {
483 wrote = count;
484 if (count > (unsigned long) high_memory - p)
485 wrote = (unsigned long) high_memory - p;
487 written = do_write_kmem((void*)p, p, buf, wrote, ppos);
488 if (written != wrote)
489 return written;
490 wrote = written;
491 p += wrote;
492 buf += wrote;
493 count -= wrote;
494 }
496 if (count > 0) {
497 kbuf = (char *)__get_free_page(GFP_KERNEL);
498 if (!kbuf)
499 return wrote ? wrote : -ENOMEM;
500 while (count > 0) {
501 int len = count;
503 if (len > PAGE_SIZE)
504 len = PAGE_SIZE;
505 if (len) {
506 written = copy_from_user(kbuf, buf, len);
507 if (written) {
508 if (wrote + virtr)
509 break;
510 free_page((unsigned long)kbuf);
511 return -EFAULT;
512 }
513 }
514 len = vwrite(kbuf, (char *)p, len);
515 count -= len;
516 buf += len;
517 virtr += len;
518 p += len;
519 }
520 free_page((unsigned long)kbuf);
521 }
523 *ppos = p;
524 return virtr + wrote;
525 }
527 #if defined(CONFIG_ISA) || !defined(__mc68000__)
528 static ssize_t read_port(struct file * file, char __user * buf,
529 size_t count, loff_t *ppos)
530 {
531 unsigned long i = *ppos;
532 char __user *tmp = buf;
534 if (!access_ok(VERIFY_WRITE, buf, count))
535 return -EFAULT;
536 while (count-- > 0 && i < 65536) {
537 if (__put_user(inb(i),tmp) < 0)
538 return -EFAULT;
539 i++;
540 tmp++;
541 }
542 *ppos = i;
543 return tmp-buf;
544 }
546 static ssize_t write_port(struct file * file, const char __user * buf,
547 size_t count, loff_t *ppos)
548 {
549 unsigned long i = *ppos;
550 const char __user * tmp = buf;
552 if (!access_ok(VERIFY_READ,buf,count))
553 return -EFAULT;
554 while (count-- > 0 && i < 65536) {
555 char c;
556 if (__get_user(c, tmp)) {
557 if (tmp > buf)
558 break;
559 return -EFAULT;
560 }
561 outb(c,i);
562 i++;
563 tmp++;
564 }
565 *ppos = i;
566 return tmp-buf;
567 }
568 #endif
570 static ssize_t read_null(struct file * file, char __user * buf,
571 size_t count, loff_t *ppos)
572 {
573 return 0;
574 }
576 static ssize_t write_null(struct file * file, const char __user * buf,
577 size_t count, loff_t *ppos)
578 {
579 return count;
580 }
582 static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf,
583 struct splice_desc *sd)
584 {
585 return sd->len;
586 }
588 static ssize_t splice_write_null(struct pipe_inode_info *pipe,struct file *out,
589 loff_t *ppos, size_t len, unsigned int flags)
590 {
591 return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null);
592 }
594 #ifdef CONFIG_MMU
595 /*
596 * For fun, we are using the MMU for this.
597 */
598 static inline size_t read_zero_pagealigned(char __user * buf, size_t size)
599 {
600 struct mm_struct *mm;
601 struct vm_area_struct * vma;
602 unsigned long addr=(unsigned long)buf;
604 mm = current->mm;
605 /* Oops, this was forgotten before. -ben */
606 down_read(&mm->mmap_sem);
608 /* For private mappings, just map in zero pages. */
609 for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) {
610 unsigned long count;
612 if (vma->vm_start > addr || (vma->vm_flags & VM_WRITE) == 0)
613 goto out_up;
614 if (vma->vm_flags & (VM_SHARED | VM_HUGETLB))
615 break;
616 count = vma->vm_end - addr;
617 if (count > size)
618 count = size;
620 zap_page_range(vma, addr, count, NULL);
621 zeromap_page_range(vma, addr, count, PAGE_COPY);
623 size -= count;
624 buf += count;
625 addr += count;
626 if (size == 0)
627 goto out_up;
628 }
630 up_read(&mm->mmap_sem);
632 /* The shared case is hard. Let's do the conventional zeroing. */
633 do {
634 unsigned long unwritten = clear_user(buf, PAGE_SIZE);
635 if (unwritten)
636 return size + unwritten - PAGE_SIZE;
637 cond_resched();
638 buf += PAGE_SIZE;
639 size -= PAGE_SIZE;
640 } while (size);
642 return size;
643 out_up:
644 up_read(&mm->mmap_sem);
645 return size;
646 }
648 static ssize_t read_zero(struct file * file, char __user * buf,
649 size_t count, loff_t *ppos)
650 {
651 unsigned long left, unwritten, written = 0;
653 if (!count)
654 return 0;
656 if (!access_ok(VERIFY_WRITE, buf, count))
657 return -EFAULT;
659 left = count;
661 /* do we want to be clever? Arbitrary cut-off */
662 if (count >= PAGE_SIZE*4) {
663 unsigned long partial;
665 /* How much left of the page? */
666 partial = (PAGE_SIZE-1) & -(unsigned long) buf;
667 unwritten = clear_user(buf, partial);
668 written = partial - unwritten;
669 if (unwritten)
670 goto out;
671 left -= partial;
672 buf += partial;
673 unwritten = read_zero_pagealigned(buf, left & PAGE_MASK);
674 written += (left & PAGE_MASK) - unwritten;
675 if (unwritten)
676 goto out;
677 buf += left & PAGE_MASK;
678 left &= ~PAGE_MASK;
679 }
680 unwritten = clear_user(buf, left);
681 written += left - unwritten;
682 out:
683 return written ? written : -EFAULT;
684 }
686 static int mmap_zero(struct file * file, struct vm_area_struct * vma)
687 {
688 if (vma->vm_flags & VM_SHARED)
689 return shmem_zero_setup(vma);
690 if (zeromap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start, vma->vm_page_prot))
691 return -EAGAIN;
692 return 0;
693 }
694 #else /* CONFIG_MMU */
695 static ssize_t read_zero(struct file * file, char * buf,
696 size_t count, loff_t *ppos)
697 {
698 size_t todo = count;
700 while (todo) {
701 size_t chunk = todo;
703 if (chunk > 4096)
704 chunk = 4096; /* Just for latency reasons */
705 if (clear_user(buf, chunk))
706 return -EFAULT;
707 buf += chunk;
708 todo -= chunk;
709 cond_resched();
710 }
711 return count;
712 }
714 static int mmap_zero(struct file * file, struct vm_area_struct * vma)
715 {
716 return -ENOSYS;
717 }
718 #endif /* CONFIG_MMU */
720 static ssize_t write_full(struct file * file, const char __user * buf,
721 size_t count, loff_t *ppos)
722 {
723 return -ENOSPC;
724 }
726 /*
727 * Special lseek() function for /dev/null and /dev/zero. Most notably, you
728 * can fopen() both devices with "a" now. This was previously impossible.
729 * -- SRB.
730 */
732 static loff_t null_lseek(struct file * file, loff_t offset, int orig)
733 {
734 return file->f_pos = 0;
735 }
737 /*
738 * The memory devices use the full 32/64 bits of the offset, and so we cannot
739 * check against negative addresses: they are ok. The return value is weird,
740 * though, in that case (0).
741 *
742 * also note that seeking relative to the "end of file" isn't supported:
743 * it has no meaning, so it returns -EINVAL.
744 */
745 static loff_t memory_lseek(struct file * file, loff_t offset, int orig)
746 {
747 loff_t ret;
749 mutex_lock(&file->f_dentry->d_inode->i_mutex);
750 switch (orig) {
751 case 0:
752 file->f_pos = offset;
753 ret = file->f_pos;
754 force_successful_syscall_return();
755 break;
756 case 1:
757 file->f_pos += offset;
758 ret = file->f_pos;
759 force_successful_syscall_return();
760 break;
761 default:
762 ret = -EINVAL;
763 }
764 mutex_unlock(&file->f_dentry->d_inode->i_mutex);
765 return ret;
766 }
768 static int open_port(struct inode * inode, struct file * filp)
769 {
770 return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
771 }
773 #define zero_lseek null_lseek
774 #define full_lseek null_lseek
775 #define write_zero write_null
776 #define read_full read_zero
777 #define open_mem open_port
778 #define open_kmem open_mem
779 #define open_oldmem open_mem
781 #ifndef ARCH_HAS_DEV_MEM
782 static const struct file_operations mem_fops = {
783 .llseek = memory_lseek,
784 .read = read_mem,
785 .write = write_mem,
786 .mmap = mmap_mem,
787 .open = open_mem,
788 };
789 #else
790 extern struct file_operations mem_fops;
791 #endif
793 static const struct file_operations kmem_fops = {
794 .llseek = memory_lseek,
795 .read = read_kmem,
796 .write = write_kmem,
797 .mmap = mmap_kmem,
798 .open = open_kmem,
799 };
801 static const struct file_operations null_fops = {
802 .llseek = null_lseek,
803 .read = read_null,
804 .write = write_null,
805 .splice_write = splice_write_null,
806 };
808 #if defined(CONFIG_ISA) || !defined(__mc68000__)
809 static const struct file_operations port_fops = {
810 .llseek = memory_lseek,
811 .read = read_port,
812 .write = write_port,
813 .open = open_port,
814 };
815 #endif
817 static const struct file_operations zero_fops = {
818 .llseek = zero_lseek,
819 .read = read_zero,
820 .write = write_zero,
821 .mmap = mmap_zero,
822 };
824 static struct backing_dev_info zero_bdi = {
825 .capabilities = BDI_CAP_MAP_COPY,
826 };
828 static const struct file_operations full_fops = {
829 .llseek = full_lseek,
830 .read = read_full,
831 .write = write_full,
832 };
834 #ifdef CONFIG_CRASH_DUMP
835 static const struct file_operations oldmem_fops = {
836 .read = read_oldmem,
837 .open = open_oldmem,
838 };
839 #endif
841 static ssize_t kmsg_write(struct file * file, const char __user * buf,
842 size_t count, loff_t *ppos)
843 {
844 char *tmp;
845 ssize_t ret;
847 tmp = kmalloc(count + 1, GFP_KERNEL);
848 if (tmp == NULL)
849 return -ENOMEM;
850 ret = -EFAULT;
851 if (!copy_from_user(tmp, buf, count)) {
852 tmp[count] = 0;
853 ret = printk("%s", tmp);
854 if (ret > count)
855 /* printk can add a prefix */
856 ret = count;
857 }
858 kfree(tmp);
859 return ret;
860 }
862 static const struct file_operations kmsg_fops = {
863 .write = kmsg_write,
864 };
866 static int memory_open(struct inode * inode, struct file * filp)
867 {
868 switch (iminor(inode)) {
869 case 1:
870 filp->f_op = &mem_fops;
871 break;
872 case 2:
873 filp->f_op = &kmem_fops;
874 break;
875 case 3:
876 filp->f_op = &null_fops;
877 break;
878 #if defined(CONFIG_ISA) || !defined(__mc68000__)
879 case 4:
880 filp->f_op = &port_fops;
881 break;
882 #endif
883 case 5:
884 filp->f_mapping->backing_dev_info = &zero_bdi;
885 filp->f_op = &zero_fops;
886 break;
887 case 7:
888 filp->f_op = &full_fops;
889 break;
890 case 8:
891 filp->f_op = &random_fops;
892 break;
893 case 9:
894 filp->f_op = &urandom_fops;
895 break;
896 case 11:
897 filp->f_op = &kmsg_fops;
898 break;
899 #ifdef CONFIG_CRASH_DUMP
900 case 12:
901 filp->f_op = &oldmem_fops;
902 break;
903 #endif
904 default:
905 return -ENXIO;
906 }
907 if (filp->f_op && filp->f_op->open)
908 return filp->f_op->open(inode,filp);
909 return 0;
910 }
912 static const struct file_operations memory_fops = {
913 .open = memory_open, /* just a selector for the real open */
914 };
916 static const struct {
917 unsigned int minor;
918 char *name;
919 umode_t mode;
920 const struct file_operations *fops;
921 } devlist[] = { /* list of minor devices */
922 {1, "mem", S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops},
923 {2, "kmem", S_IRUSR | S_IWUSR | S_IRGRP, &kmem_fops},
924 {3, "null", S_IRUGO | S_IWUGO, &null_fops},
925 #if defined(CONFIG_ISA) || !defined(__mc68000__)
926 {4, "port", S_IRUSR | S_IWUSR | S_IRGRP, &port_fops},
927 #endif
928 {5, "zero", S_IRUGO | S_IWUGO, &zero_fops},
929 {7, "full", S_IRUGO | S_IWUGO, &full_fops},
930 {8, "random", S_IRUGO | S_IWUSR, &random_fops},
931 {9, "urandom", S_IRUGO | S_IWUSR, &urandom_fops},
932 {11,"kmsg", S_IRUGO | S_IWUSR, &kmsg_fops},
933 #ifdef CONFIG_CRASH_DUMP
934 {12,"oldmem", S_IRUSR | S_IWUSR | S_IRGRP, &oldmem_fops},
935 #endif
936 };
938 static struct class *mem_class;
940 static int __init chr_dev_init(void)
941 {
942 int i;
944 if (register_chrdev(MEM_MAJOR,"mem",&memory_fops))
945 printk("unable to get major %d for memory devs\n", MEM_MAJOR);
947 mem_class = class_create(THIS_MODULE, "mem");
948 for (i = 0; i < ARRAY_SIZE(devlist); i++)
949 class_device_create(mem_class, NULL,
950 MKDEV(MEM_MAJOR, devlist[i].minor),
951 NULL, devlist[i].name);
953 return 0;
954 }
956 fs_initcall(chr_dev_init);