This commit was manufactured by cvs2svn to create branch 'vserver'.

[linux-2.6.git] / arch / i386 / kernel / ioport-xen.c

diff --git a/arch/i386/kernel/ioport-xen.c b/arch/i386/kernel/ioport-xen.c
new file mode 100644 (file)
index 0000000..ee66fc2
--- /dev/null
+++ b/arch/i386/kernel/ioport-xen.c
@@ -0,0 +1,121 @@
+/*
+ *     linux/arch/i386/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/capability.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/ioport.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+#include <linux/stddef.h>
+#include <linux/slab.h>
+#include <linux/thread_info.h>
+#include <xen/interface/physdev.h>
+
+/* Set EXTENT bits starting at BASE in BITMAP to value TURN_ON. */
+static void set_bitmap(unsigned long *bitmap, unsigned int base, unsigned int extent, int new_value)
+{
+       unsigned long mask;
+       unsigned long *bitmap_base = bitmap + (base / BITS_PER_LONG);
+       unsigned int low_index = base & (BITS_PER_LONG-1);
+       int length = low_index + extent;
+
+       if (low_index != 0) {
+               mask = (~0UL << low_index);
+               if (length < BITS_PER_LONG)
+                       mask &= ~(~0UL << length);
+               if (new_value)
+                       *bitmap_base++ |= mask;
+               else
+                       *bitmap_base++ &= ~mask;
+               length -= BITS_PER_LONG;
+       }
+
+       mask = (new_value ? ~0UL : 0UL);
+       while (length >= BITS_PER_LONG) {
+               *bitmap_base++ = mask;
+               length -= BITS_PER_LONG;
+       }
+
+       if (length > 0) {
+               mask = ~(~0UL << length);
+               if (new_value)
+                       *bitmap_base++ |= mask;
+               else
+                       *bitmap_base++ &= ~mask;
+       }
+}
+
+
+/*
+ * 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;
+       unsigned long *bitmap;
+       struct physdev_set_iobitmap set_iobitmap;
+
+       if ((from + num <= from) || (from + num > IO_BITMAP_BITS))
+               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) {
+               bitmap = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL);
+               if (!bitmap)
+                       return -ENOMEM;
+
+               memset(bitmap, 0xff, IO_BITMAP_BYTES);
+               t->io_bitmap_ptr = bitmap;
+
+               set_iobitmap.bitmap   = (char *)bitmap;
+               set_iobitmap.nr_ports = IO_BITMAP_BITS;
+               HYPERVISOR_physdev_op(PHYSDEVOP_set_iobitmap, &set_iobitmap);
+       }
+
+       set_bitmap(t->io_bitmap_ptr, 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 long unused)
+{
+       volatile struct pt_regs * regs = (struct pt_regs *) &unused;
+       unsigned int level = regs->ebx;
+       struct thread_struct *t = &current->thread;
+       unsigned int old = (t->iopl >> 12) & 3;
+
+       if (level > 3)
+               return -EINVAL;
+       /* Trying to gain more privileges? */
+       if (level > old) {
+               if (!capable(CAP_SYS_RAWIO))
+                       return -EPERM;
+       }
+       t->iopl = level << 12;
+       set_iopl_mask(t->iopl);
+       return 0;
+}