/*
* linux/drivers/char/mem.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* Added devfs support.
* Jan-11-1998, C. Scott Ananian <cananian@alumni.princeton.edu>
* Shared /dev/zero mmaping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com>
*/
#include <linux/config.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/tpqic02.h>
#include <linux/ftape.h>
#include <linux/malloc.h>
#include <linux/vmalloc.h>
#include <linux/mman.h>
#include <linux/random.h>
#include <linux/init.h>
#include <linux/raw.h>
#include <linux/capability.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/pgalloc.h>
#ifdef CONFIG_I2C
extern int i2c_init_all(void);
#endif
#ifdef CONFIG_ISDN
int isdn_init(void);
#endif
#ifdef CONFIG_VIDEO_DEV
extern int videodev_init(void);
#endif
#ifdef CONFIG_FB
extern void fbmem_init(void);
#endif
#ifdef CONFIG_PROM_CONSOLE
extern void prom_con_init(void);
#endif
#ifdef CONFIG_MDA_CONSOLE
extern void mda_console_init(void);
#endif
#if defined(CONFIG_ADB)
extern void adbdev_init(void);
#endif
50 static ssize_t do_write_mem(struct file * file, void *p, unsigned long realp,
const char * buf, size_t count, loff_t *ppos)
{
ssize_t written;
written = 0;
#if defined(__sparc__) || defined(__mc68000__)
/* we don't have page 0 mapped on sparc and m68k.. */
if (realp < PAGE_SIZE) {
unsigned long sz = PAGE_SIZE-realp;
if (sz > count) sz = count;
/* Hmm. Do something? */
buf+=sz;
p+=sz;
count-=sz;
written+=sz;
}
#endif
68 if (copy_from_user(p, buf, count))
69 return -EFAULT;
written += count;
*ppos += written;
72 return written;
}
/*
* This funcion reads the *physical* memory. The f_pos points directly to the
* memory location.
*/
80 static ssize_t read_mem(struct file * file, char * buf,
size_t count, loff_t *ppos)
{
unsigned long p = *ppos;
unsigned long end_mem;
ssize_t read;
end_mem = __pa(high_memory);
88 if (p >= end_mem)
89 return 0;
90 if (count > end_mem - p)
count = end_mem - p;
read = 0;
#if defined(__sparc__) || defined(__mc68000__)
/* we don't have page 0 mapped on sparc and m68k.. */
if (p < PAGE_SIZE) {
unsigned long sz = PAGE_SIZE-p;
if (sz > count)
sz = count;
if (sz > 0) {
if (clear_user(buf, sz))
return -EFAULT;
buf += sz;
p += sz;
count -= sz;
read += sz;
}
}
#endif
109 if (copy_to_user(buf, __va(p), count))
110 return -EFAULT;
read += count;
*ppos += read;
113 return read;
}
116 static ssize_t write_mem(struct file * file, const char * buf,
size_t count, loff_t *ppos)
{
unsigned long p = *ppos;
unsigned long end_mem;
end_mem = __pa(high_memory);
123 if (p >= end_mem)
124 return 0;
125 if (count > end_mem - p)
count = end_mem - p;
127 return do_write_mem(file, __va(p), p, buf, count, ppos);
}
#ifndef pgprot_noncached
/*
* This should probably be per-architecture in <asm/pgtable.h>
*/
135 static inline pgprot_t pgprot_noncached(pgprot_t _prot)
{
unsigned long prot = pgprot_val(_prot);
#if defined(__i386__)
/* On PPro and successors, PCD alone doesn't always mean
uncached because of interactions with the MTRRs. PCD | PWT
means definitely uncached. */
143 if (boot_cpu_data.x86 > 3)
prot |= _PAGE_PCD | _PAGE_PWT;
#elif defined(__powerpc__)
prot |= _PAGE_NO_CACHE | _PAGE_GUARDED;
#elif defined(__mc68000__)
#ifdef SUN3_PAGE_NOCACHE
if (MMU_IS_SUN3)
prot |= SUN3_PAGE_NOCACHE;
else
#endif
if (MMU_IS_851 || MMU_IS_030)
prot |= _PAGE_NOCACHE030;
/* Use no-cache mode, serialized */
else if (MMU_IS_040 || MMU_IS_060)
prot = (prot & _CACHEMASK040) | _PAGE_NOCACHE_S;
#elif defined(__mips__)
prot = (prot & ~_CACHE_MASK) | _CACHE_UNCACHED;
#elif defined(__arm__) && defined(CONFIG_CPU_32)
/* Turn off caching for all I/O areas */
prot &= ~(L_PTE_CACHEABLE | L_PTE_BUFFERABLE);
#endif
165 return __pgprot(prot);
}
#endif /* !pgprot_noncached */
/*
* Architectures vary in how they handle caching for addresses
* outside of main memory.
*/
174 static inline int noncached_address(unsigned long addr)
{
#if defined(__i386__)
/*
* On the PPro and successors, the MTRRs are used to set
* memory types for physical addresses outside main memory,
* so blindly setting PCD or PWT on those pages is wrong.
* For Pentiums and earlier, the surround logic should disable
* caching for the high addresses through the KEN pin, but
* we maintain the tradition of paranoia in this code.
*/
return !( test_bit(X86_FEATURE_MTRR, &boot_cpu_data.x86_capability) ||
test_bit(X86_FEATURE_K6_MTRR, &boot_cpu_data.x86_capability) ||
test_bit(X86_FEATURE_CYRIX_ARR, &boot_cpu_data.x86_capability) ||
test_bit(X86_FEATURE_CENTAUR_MCR, &boot_cpu_data.x86_capability) )
189 && addr >= __pa(high_memory);
#else
return addr >= __pa(high_memory);
#endif
}
195 static int mmap_mem(struct file * file, struct vm_area_struct * vma)
{
unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
/*
* Accessing memory above the top the kernel knows about or
* through a file pointer that was marked O_SYNC will be
* done non-cached.
*/
204 if (noncached_address(offset) || (file->f_flags & O_SYNC))
vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
/* Don't try to swap out physical pages.. */
vma->vm_flags |= VM_RESERVED;
/*
* Don't dump addresses that are not real memory to a core file.
*/
213 if (offset >= __pa(high_memory) || (file->f_flags & O_SYNC))
vma->vm_flags |= VM_IO;
if (remap_page_range(vma->vm_start, offset, vma->vm_end-vma->vm_start,
217 vma->vm_page_prot))
218 return -EAGAIN;
219 return 0;
}
/*
* This function reads the *virtual* memory as seen by the kernel.
*/
225 static ssize_t read_kmem(struct file *file, char *buf,
size_t count, loff_t *ppos)
{
unsigned long p = *ppos;
ssize_t read = 0;
ssize_t virtr = 0;
char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */
233 if (p < (unsigned long) high_memory) {
read = count;
235 if (count > (unsigned long) high_memory - p)
read = (unsigned long) high_memory - p;
#if defined(__sparc__) || defined(__mc68000__)
/* we don't have page 0 mapped on sparc and m68k.. */
if (p < PAGE_SIZE && read > 0) {
size_t tmp = PAGE_SIZE - p;
if (tmp > read) tmp = read;
if (clear_user(buf, tmp))
return -EFAULT;
buf += tmp;
p += tmp;
read -= tmp;
count -= tmp;
}
#endif
251 if (copy_to_user(buf, (char *)p, read))
252 return -EFAULT;
p += read;
buf += read;
count -= read;
}
258 if (count > 0) {
kbuf = (char *)__get_free_page(GFP_KERNEL);
260 if (!kbuf)
261 return -ENOMEM;
262 while (count > 0) {
int len = count;
265 if (len > PAGE_SIZE)
len = PAGE_SIZE;
len = vread(kbuf, (char *)p, len);
268 if (len && copy_to_user(buf, kbuf, len)) {
free_page((unsigned long)kbuf);
270 return -EFAULT;
}
count -= len;
buf += len;
virtr += len;
p += len;
}
free_page((unsigned long)kbuf);
}
*ppos = p;
280 return virtr + read;
}
/*
* This function writes to the *virtual* memory as seen by the kernel.
*/
286 static ssize_t write_kmem(struct file * file, const char * buf,
size_t count, loff_t *ppos)
{
unsigned long p = *ppos;
291 if (p >= (unsigned long) high_memory)
292 return 0;
293 if (count > (unsigned long) high_memory - p)
count = (unsigned long) high_memory - p;
295 return do_write_mem(file, (void*)p, p, buf, count, ppos);
}
#if !defined(__mc68000__)
299 static ssize_t read_port(struct file * file, char * buf,
size_t count, loff_t *ppos)
{
unsigned long i = *ppos;
char *tmp = buf;
305 if (verify_area(VERIFY_WRITE,buf,count))
306 return -EFAULT;
307 while (count-- > 0 && i < 65536) {
308 if (__put_user(inb(i),tmp) < 0)
309 return -EFAULT;
i++;
tmp++;
}
*ppos = i;
314 return tmp-buf;
}
317 static ssize_t write_port(struct file * file, const char * buf,
size_t count, loff_t *ppos)
{
unsigned long i = *ppos;
const char * tmp = buf;
323 if (verify_area(VERIFY_READ,buf,count))
324 return -EFAULT;
325 while (count-- > 0 && i < 65536) {
char c;
327 if (__get_user(c, tmp))
328 return -EFAULT;
outb(c,i);
i++;
tmp++;
}
*ppos = i;
334 return tmp-buf;
}
#endif
338 static ssize_t read_null(struct file * file, char * buf,
size_t count, loff_t *ppos)
{
341 return 0;
}
344 static ssize_t write_null(struct file * file, const char * buf,
size_t count, loff_t *ppos)
{
347 return count;
}
/*
* For fun, we are using the MMU for this.
*/
353 static inline size_t read_zero_pagealigned(char * buf, size_t size)
{
struct mm_struct *mm;
struct vm_area_struct * vma;
unsigned long addr=(unsigned long)buf;
mm = current->mm;
/* Oops, this was forgotten before. -ben */
down(&mm->mmap_sem);
/* For private mappings, just map in zero pages. */
364 for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) {
unsigned long count;
367 if (vma->vm_start > addr || (vma->vm_flags & VM_WRITE) == 0)
368 goto out_up;
369 if (vma->vm_flags & VM_SHARED)
370 break;
count = vma->vm_end - addr;
372 if (count > size)
count = size;
375 flush_cache_range(mm, addr, addr + count);
zap_page_range(mm, addr, count);
zeromap_page_range(addr, count, PAGE_COPY);
flush_tlb_range(mm, addr, addr + count);
size -= count;
buf += count;
addr += count;
383 if (size == 0)
384 goto out_up;
}
up(&mm->mmap_sem);
/* The shared case is hard. Let's do the conventional zeroing. */
390 do {
unsigned long unwritten = clear_user(buf, PAGE_SIZE);
392 if (unwritten)
393 return size + unwritten - PAGE_SIZE;
394 if (current->need_resched)
schedule();
buf += PAGE_SIZE;
size -= PAGE_SIZE;
398 } while (size);
400 return size;
out_up:
up(&mm->mmap_sem);
403 return size;
}
406 static ssize_t read_zero(struct file * file, char * buf,
size_t count, loff_t *ppos)
{
unsigned long left, unwritten, written = 0;
411 if (!count)
412 return 0;
414 if (!access_ok(VERIFY_WRITE, buf, count))
415 return -EFAULT;
left = count;
/* do we want to be clever? Arbitrary cut-off */
420 if (count >= PAGE_SIZE*4) {
unsigned long partial;
/* How much left of the page? */
partial = (PAGE_SIZE-1) & -(unsigned long) buf;
unwritten = clear_user(buf, partial);
written = partial - unwritten;
427 if (unwritten)
428 goto out;
left -= partial;
buf += partial;
unwritten = read_zero_pagealigned(buf, left & PAGE_MASK);
written += (left & PAGE_MASK) - unwritten;
433 if (unwritten)
434 goto out;
buf += left & PAGE_MASK;
left &= ~PAGE_MASK;
}
unwritten = clear_user(buf, left);
written += left - unwritten;
out:
441 return written ? written : -EFAULT;
}
444 static int mmap_zero(struct file * file, struct vm_area_struct * vma)
{
446 if (vma->vm_flags & VM_SHARED)
447 return shmem_zero_setup(vma);
448 if (zeromap_page_range(vma->vm_start, vma->vm_end - vma->vm_start, vma->vm_page_prot))
449 return -EAGAIN;
450 return 0;
}
453 static ssize_t write_full(struct file * file, const char * buf,
size_t count, loff_t *ppos)
{
456 return -ENOSPC;
}
/*
* Special lseek() function for /dev/null and /dev/zero. Most notably, you
* can fopen() both devices with "a" now. This was previously impossible.
* -- SRB.
*/
465 static loff_t null_lseek(struct file * file, loff_t offset, int orig)
{
467 return file->f_pos = 0;
}
/*
* The memory devices use the full 32/64 bits of the offset, and so we cannot
* check against negative addresses: they are ok. The return value is weird,
* though, in that case (0).
*
* also note that seeking relative to the "end of file" isn't supported:
* it has no meaning, so it returns -EINVAL.
*/
478 static loff_t memory_lseek(struct file * file, loff_t offset, int orig)
{
480 switch (orig) {
481 case 0:
file->f_pos = offset;
483 return file->f_pos;
484 case 1:
file->f_pos += offset;
486 return file->f_pos;
487 default:
488 return -EINVAL;
}
}
492 static int open_port(struct inode * inode, struct file * filp)
{
494 return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
}
#define mmap_kmem mmap_mem
#define zero_lseek null_lseek
#define full_lseek null_lseek
#define write_zero write_null
#define read_full read_zero
#define open_mem open_port
#define open_kmem open_mem
static struct file_operations mem_fops = {
llseek: memory_lseek,
read: read_mem,
write: write_mem,
mmap: mmap_mem,
open: open_mem,
};
static struct file_operations kmem_fops = {
llseek: memory_lseek,
read: read_kmem,
write: write_kmem,
mmap: mmap_kmem,
open: open_kmem,
};
static struct file_operations null_fops = {
llseek: null_lseek,
read: read_null,
write: write_null,
};
#if !defined(__mc68000__)
static struct file_operations port_fops = {
llseek: memory_lseek,
read: read_port,
write: write_port,
open: open_port,
};
#endif
static struct file_operations zero_fops = {
llseek: zero_lseek,
read: read_zero,
write: write_zero,
mmap: mmap_zero,
};
static struct file_operations full_fops = {
llseek: full_lseek,
read: read_full,
write: write_full,
};
549 static int memory_open(struct inode * inode, struct file * filp)
{
551 switch (MINOR(inode->i_rdev)) {
552 case 1:
filp->f_op = &mem_fops;
554 break;
555 case 2:
filp->f_op = &kmem_fops;
557 break;
558 case 3:
filp->f_op = &null_fops;
560 break;
#if !defined(__mc68000__)
562 case 4:
filp->f_op = &port_fops;
564 break;
#endif
566 case 5:
filp->f_op = &zero_fops;
568 break;
569 case 7:
filp->f_op = &full_fops;
571 break;
572 case 8:
filp->f_op = &random_fops;
574 break;
575 case 9:
filp->f_op = &urandom_fops;
577 break;
578 default:
579 return -ENXIO;
}
581 if (filp->f_op && filp->f_op->open)
582 return filp->f_op->open(inode,filp);
583 return 0;
}
586 void __init memory_devfs_register (void)
{
/* These are never unregistered */
static const struct {
unsigned short minor;
char *name;
umode_t mode;
struct file_operations *fops;
} list[] = { /* list of minor devices */
{1, "mem", S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops},
{2, "kmem", S_IRUSR | S_IWUSR | S_IRGRP, &kmem_fops},
{3, "null", S_IRUGO | S_IWUGO, &null_fops},
{4, "port", S_IRUSR | S_IWUSR | S_IRGRP, &port_fops},
{5, "zero", S_IRUGO | S_IWUGO, &zero_fops},
{7, "full", S_IRUGO | S_IWUGO, &full_fops},
{8, "random", S_IRUGO | S_IWUSR, &random_fops},
{9, "urandom", S_IRUGO | S_IWUSR, &urandom_fops}
};
int i;
606 for (i=0; i<(sizeof(list)/sizeof(*list)); i++)
devfs_register (NULL, list[i].name, DEVFS_FL_NONE,
MEM_MAJOR, list[i].minor,
list[i].mode | S_IFCHR,
list[i].fops, NULL);
}
static struct file_operations memory_fops = {
open: memory_open, /* just a selector for the real open */
};
617 int __init chr_dev_init(void)
{
619 if (devfs_register_chrdev(MEM_MAJOR,"mem",&memory_fops))
printk("unable to get major %d for memory devs\n", MEM_MAJOR);
memory_devfs_register();
rand_initialize();
raw_init();
#ifdef CONFIG_I2C
i2c_init_all();
#endif
#if defined (CONFIG_FB)
fbmem_init();
#endif
#if defined (CONFIG_PROM_CONSOLE)
prom_con_init();
#endif
#if defined (CONFIG_MDA_CONSOLE)
mda_console_init();
#endif
tty_init();
#ifdef CONFIG_PRINTER
lp_init();
#endif
#ifdef CONFIG_M68K_PRINTER
lp_m68k_init();
#endif
misc_init();
#if CONFIG_QIC02_TAPE
qic02_tape_init();
#endif
#if CONFIG_ISDN
isdn_init();
#endif
#ifdef CONFIG_FTAPE
ftape_init();
#endif
#if defined(CONFIG_ADB)
adbdev_init();
#endif
#ifdef CONFIG_VIDEO_DEV
videodev_init();
#endif
659 return 0;
}