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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [arch/] [x86_64/] [kernel/] [ioport.c] - Rev 1765
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/* * 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 = ¤t->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 & 0xffffffffffffcfff) | (level << 12); return 0; }