[patch 4/4] Xen core patch : /dev/mem calls io_remap_page_range

[Ian Pratt <Ian.Pratt@cl.cam.ac.uk>]

This patch modifies /dev/mem to call io_remap_page_range rather than
remap_page_range under CONFIG_XEN.  (the two definitions are different
under arch xen, unlike most other architectures).  This allows the X
server and other programs that use /dev/mem for MMIO to work under
Xen. 

Signed-off-by: ian.pratt@cl.cam.ac.uk

---


diff -Nurp pristine-linux-2.6.9/drivers/char/mem.c linux-2.6.9-xen0/drivers/char/mem.c
--- pristine-linux-2.6.9/drivers/char/mem.c     2004-10-18 22:54:19.000000000 +0100
+++ linux-2.6.9-xen0/drivers/char/mem.c 2004-11-17 00:12:37.000000000 +0000
@@ -26,6 +26,7 @@
 
 #include <asm/uaccess.h>
 #include <asm/io.h>
+#include <asm/pgalloc.h>
 
 #ifdef CONFIG_IA64
 # include <linux/efi.h>
@@ -42,7 +43,12 @@ extern void tapechar_init(void);
  */
 static inline int uncached_access(struct file *file, unsigned long addr)
 {
-#if defined(__i386__)
+#ifdef CONFIG_XEN
+        if (file->f_flags & O_SYNC)
+                return 1;
+        /* Xen sets correct MTRR type on non-RAM for us. */
+        return 0;
+#elif defined(__i386__)
        /*
         * On the PPro and successors, the MTRRs are used to set
         * memory types for physical addresses outside main memory,
@@ -210,9 +216,15 @@ static int mmap_mem(struct file * file, 
        if (uncached)
                vma->vm_flags |= VM_IO;
 
+#if defined(CONFIG_XEN)
+       if (io_remap_page_range(vma, vma->vm_start, offset, 
+                               vma->vm_end-vma->vm_start, vma->vm_page_prot))
+               return -EAGAIN;
+#else
        if (remap_page_range(vma, vma->vm_start, offset, vma->vm_end-vma->vm_start,
                             vma->vm_page_prot))
                return -EAGAIN;
+#endif
        return 0;
 }