blob: d96d85b05f2692b4fd291c56abbceb02c9525b84 [file] [log] [blame]
/*
* linux/arch/x86_64/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>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/stddef.h>
/* Set EXTENT bits starting at BASE in BITMAP to value TURN_ON. */
static void set_bitmap(unsigned long *bitmap, short base, short extent, int new_value)
{
int i;
if (new_value)
for (i = base; i < base + extent; i++)
__set_bit(i, bitmap);
else
for (i = base; i < base + extent; i++)
clear_bit(i, bitmap);
}
/*
* this changes the io permissions bitmap in the current task.
*/
asmlinkage long sys_ioperm(unsigned long from, unsigned long num, int turn_on)
{
struct thread_struct * t = &current->thread;
struct tss_struct * tss = init_tss + smp_processor_id();
if ((from + num <= from) || (from + num > IO_BITMAP_SIZE*32))
return -EINVAL;
if (turn_on && !capable(CAP_SYS_RAWIO))
return -EPERM;
/*
* If it's the first ioperm() call in this thread's lifetime, set the
* IO bitmap up. ioperm() is much less timing critical than clone(),
* this is why we delay this operation until now:
*/
if (!t->io_bitmap_ptr) {
t->io_bitmap_ptr = kmalloc((IO_BITMAP_SIZE+1)*4, GFP_KERNEL);
if (!t->io_bitmap_ptr)
return -ENOMEM;
memset(t->io_bitmap_ptr,0xff,(IO_BITMAP_SIZE+1)*4);
/*
* this activates it in the TSS
*/
}
/*
* do it in the per-thread copy and in the TSS ...
*/
set_bitmap((unsigned long *) t->io_bitmap_ptr, from, num, !turn_on);
if (tss->io_map_base != IO_BITMAP_OFFSET) {
memcpy(tss->io_bitmap, t->io_bitmap_ptr, sizeof(tss->io_bitmap));
tss->io_map_base = IO_BITMAP_OFFSET;
} else {
set_bitmap((unsigned long *) tss->io_bitmap, from, num, !turn_on);
}
return 0;
}
/*
* 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 long sys_iopl(unsigned int level, struct pt_regs *regs)
{
unsigned int old = (regs->eflags >> 12) & 3;
if (level > 3)
return -EINVAL;
/* Trying to gain more privileges? */
if (level > old) {
if (!capable(CAP_SYS_RAWIO))
return -EPERM;
}
regs->eflags = (regs->eflags &~ 0x3000UL) | (level << 12);
return 0;
}