835c34a168
Since the x86 merge, lots of files that referenced their own filenames are no longer correct. Rather than keep them up to date, just delete them, as they add no real value. Additionally: - fix up comment formatting in scx200_32.c - Remove a credit from myself in setup_64.c from a time when we had no SCM - remove longwinded history from tsc_32.c which can be figured out from git. Signed-off-by: Dave Jones <davej@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
117 lines
3 KiB
C
117 lines
3 KiB
C
/*
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* This contains the io-permission bitmap code - written by obz, with changes
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* by Linus.
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*/
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/capability.h>
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#include <linux/errno.h>
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#include <linux/types.h>
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#include <linux/ioport.h>
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#include <linux/smp.h>
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#include <linux/stddef.h>
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#include <linux/slab.h>
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#include <linux/thread_info.h>
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#include <linux/syscalls.h>
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/* Set EXTENT bits starting at BASE in BITMAP to value TURN_ON. */
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static void set_bitmap(unsigned long *bitmap, unsigned int base, unsigned int extent, int new_value)
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{
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int i;
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if (new_value)
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for (i = base; i < base + extent; i++)
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__set_bit(i, bitmap);
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else
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for (i = base; i < base + extent; i++)
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clear_bit(i, bitmap);
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}
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/*
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* this changes the io permissions bitmap in the current task.
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*/
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asmlinkage long sys_ioperm(unsigned long from, unsigned long num, int turn_on)
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{
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unsigned int i, max_long, bytes, bytes_updated;
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struct thread_struct * t = ¤t->thread;
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struct tss_struct * tss;
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unsigned long *bitmap;
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if ((from + num <= from) || (from + num > IO_BITMAP_BITS))
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return -EINVAL;
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if (turn_on && !capable(CAP_SYS_RAWIO))
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return -EPERM;
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/*
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* If it's the first ioperm() call in this thread's lifetime, set the
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* IO bitmap up. ioperm() is much less timing critical than clone(),
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* this is why we delay this operation until now:
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*/
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if (!t->io_bitmap_ptr) {
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bitmap = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL);
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if (!bitmap)
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return -ENOMEM;
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memset(bitmap, 0xff, IO_BITMAP_BYTES);
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t->io_bitmap_ptr = bitmap;
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set_thread_flag(TIF_IO_BITMAP);
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}
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/*
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* do it in the per-thread copy and in the TSS ...
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*
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* Disable preemption via get_cpu() - we must not switch away
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* because the ->io_bitmap_max value must match the bitmap
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* contents:
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*/
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tss = &per_cpu(init_tss, get_cpu());
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set_bitmap(t->io_bitmap_ptr, from, num, !turn_on);
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/*
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* Search for a (possibly new) maximum. This is simple and stupid,
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* to keep it obviously correct:
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*/
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max_long = 0;
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for (i = 0; i < IO_BITMAP_LONGS; i++)
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if (t->io_bitmap_ptr[i] != ~0UL)
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max_long = i;
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bytes = (max_long + 1) * sizeof(long);
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bytes_updated = max(bytes, t->io_bitmap_max);
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t->io_bitmap_max = bytes;
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/* Update the TSS: */
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memcpy(tss->io_bitmap, t->io_bitmap_ptr, bytes_updated);
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put_cpu();
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return 0;
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}
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/*
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* sys_iopl has to be used when you want to access the IO ports
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* beyond the 0x3ff range: to get the full 65536 ports bitmapped
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* you'd need 8kB of bitmaps/process, which is a bit excessive.
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*
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* Here we just change the eflags value on the stack: we allow
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* only the super-user to do it. This depends on the stack-layout
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* on system-call entry - see also fork() and the signal handling
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* code.
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*/
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asmlinkage long sys_iopl(unsigned int level, struct pt_regs *regs)
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{
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unsigned int old = (regs->eflags >> 12) & 3;
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if (level > 3)
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return -EINVAL;
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/* Trying to gain more privileges? */
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if (level > old) {
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if (!capable(CAP_SYS_RAWIO))
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return -EPERM;
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}
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regs->eflags = (regs->eflags &~ X86_EFLAGS_IOPL) | (level << 12);
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return 0;
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}
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