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/*
* linux/kernel/ioport.c
*
* This contains the io-permission bitmap code - written by obz, with changes
* by Linus.
*/
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/ioport.h>
static unsigned long ioport_registrar[IO_BITMAP_SIZE] = {0, /* ... */};
#define _IODEBUG
#ifdef IODEBUG
static char * ios(unsigned long l)
{
static char str[33] = { '\0' };
int i;
unsigned long mask;
for (i = 0, mask = 0x80000000; i < 32; ++i, mask >>= 1)
str[i] = (l & mask) ? '1' : '0';
return str;
}
static void dump_io_bitmap(void)
{
int i, j;
int numl = sizeof(current->tss.io_bitmap) >> 2;
for (i = j = 0; j < numl; ++i)
{
printk("%4d [%3x]: ", 64*i, 64*i);
printk("%s ", ios(current->tss.io_bitmap[j++]));
if (j < numl)
printk("%s", ios(current->tss.io_bitmap[j++]));
printk("\n");
}
}
#endif
/* Set EXTENT bits starting at BASE in BITMAP to value TURN_ON. */
asmlinkage void set_bitmap(unsigned long *bitmap,
short base, short extent, int new_value)
{
int mask;
unsigned long *bitmap_base = bitmap + (base >> 5);
unsigned short low_index = base & 0x1f;
int length = low_index + extent;
if (low_index != 0) {
mask = (~0 << low_index);
if (length < 32)
mask &= ~(~0 << length);
if (new_value)
*bitmap_base++ |= mask;
else
*bitmap_base++ &= ~mask;
length -= 32;
}
mask = (new_value ? ~0 : 0);
while (length >= 32) {
*bitmap_base++ = mask;
length -= 32;
}
if (length > 0) {
mask = ~(~0 << length);
if (new_value)
*bitmap_base++ |= mask;
else
*bitmap_base++ &= ~mask;
}
}
/* Check for set bits in BITMAP starting at BASE, going to EXTENT. */
asmlinkage int check_bitmap(unsigned long *bitmap, short base, short extent)
{
int mask;
unsigned long *bitmap_base = bitmap + (base >> 5);
unsigned short low_index = base & 0x1f;
int length = low_index + extent;
if (low_index != 0) {
mask = (~0 << low_index);
if (length < 32)
mask &= ~(~0 << length);
if (*bitmap_base++ & mask)
return 1;
length -= 32;
}
while (length >= 32) {
if (*bitmap_base++ != 0)
return 1;
length -= 32;
}
if (length > 0) {
mask = ~(~0 << length);
if (*bitmap_base++ & mask)
return 1;
}
return 0;
}
/*
* this changes the io permissions bitmap in the current task.
*/
asmlinkage int sys_ioperm(unsigned long from, unsigned long num, int turn_on)
{
if (from + num <= from)
return -EINVAL;
if (from + num > IO_BITMAP_SIZE*32)
return -EINVAL;
if (!suser())
return -EPERM;
#ifdef IODEBUG
printk("io: from=%d num=%d %s\n", from, num, (turn_on ? "on" : "off"));
#endif
set_bitmap((unsigned long *)current->tss.io_bitmap, from, num, !turn_on);
return 0;
}
unsigned int *stack;
/*
* sys_iopl has to be used when you want to access the IO ports
* beyond the 0x3ff range: to get the full 65536 ports bitmapped
* you'd need 8kB of bitmaps/process, which is a bit excessive.
*
* Here we just change the eflags value on the stack: we allow
* only the super-user to do it. This depends on the stack-layout
* on system-call entry - see also fork() and the signal handling
* code.
*/
asmlinkage int sys_iopl(long ebx,long ecx,long edx,
long esi, long edi, long ebp, long eax, long ds,
long es, long fs, long gs, long orig_eax,
long eip,long cs,long eflags,long esp,long ss)
{
unsigned int level = ebx;
if (level > 3)
return -EINVAL;
if (!suser())
return -EPERM;
*(&eflags) = (eflags & 0xffffcfff) | (level << 12);
return 0;
}
void snarf_region(unsigned int from, unsigned int num)
{
if (from > IO_BITMAP_SIZE*32)
return;
if (from + num > IO_BITMAP_SIZE*32)
num = IO_BITMAP_SIZE*32 - from;
set_bitmap(ioport_registrar, from, num, 1);
return;
}
int check_region(unsigned int from, unsigned int num)
{
if (from > IO_BITMAP_SIZE*32)
return 0;
if (from + num > IO_BITMAP_SIZE*32)
num = IO_BITMAP_SIZE*32 - from;
return check_bitmap(ioport_registrar, from, num);
}
/* Called from init/main.c to reserve IO ports. */
void reserve_setup(char *str, int *ints)
{
int i;
for (i = 1; i < ints[0]; i += 2)
snarf_region(ints[i], ints[i+1]);
}