src/patches/suse-2.6.27.25/patches.arch/s390-11-02-kernel_pfn_valid_uaccess.patch

   1 From: Gerald Schaefer <geraldsc@de.ibm.com>
   2 Subject: kernel: don't check for pfn_valid() in uaccess_pt.c
   3 References: bnc#484767,LTC#52175
   4
   5 Symptom:     Access to xip mappings fails (-EFAULT).
   6 Problem:     pfn_valid() actually checks for a valid struct page and
   7              not for a valid pfn. Using xip mappings w/o struct pages,
   8              this will result in -EFAULT returned by the (page table
   9              walk) user copy functions, even though there is valid memory.
  10 Solution:    Those user copy functions don't need a struct page, so this
  11              patch just removes the pfn_valid() check.
  12
  13 Acked-by: John Jolly <jjolly@suse.de>
  14 ---
  15  arch/s390/lib/uaccess_pt.c |   18 ------------------
  16  1 file changed, 18 deletions(-)
  17
  18 Index: linux-sles11/arch/s390/lib/uaccess_pt.c
  19 ===================================================================
  20 --- linux-sles11.orig/arch/s390/lib/uaccess_pt.c
  21 +++ linux-sles11/arch/s390/lib/uaccess_pt.c
  22 @@ -119,8 +119,6 @@ retry:
  23                         goto fault;
  24
  25                 pfn = pte_pfn(*pte);
  26 -               if (!pfn_valid(pfn))
  27 -                       goto out;
  28
  29                 offset = uaddr & (PAGE_SIZE - 1);
  30                 size = min(n - done, PAGE_SIZE - offset);
  31 @@ -135,7 +133,6 @@ retry:
  32                 done += size;
  33                 uaddr += size;
  34         } while (done < n);
  35 -out:
  36         spin_unlock(&mm->page_table_lock);
  37         return n - done;
  38  fault:
  39 @@ -163,9 +160,6 @@ retry:
  40                 goto fault;
  41
  42         pfn = pte_pfn(*pte);
  43 -       if (!pfn_valid(pfn))
  44 -               goto out;
  45 -
  46         ret = (pfn << PAGE_SHIFT) + (uaddr & (PAGE_SIZE - 1));
  47  out:
  48         return ret;
  49 @@ -244,11 +238,6 @@ retry:
  50                         goto fault;
  51
  52                 pfn = pte_pfn(*pte);
  53 -               if (!pfn_valid(pfn)) {
  54 -                       done = -1;
  55 -                       goto out;
  56 -               }
  57 -
  58                 offset = uaddr & (PAGE_SIZE-1);
  59                 addr = (char *)(pfn << PAGE_SHIFT) + offset;
  60                 len = min(count - done, PAGE_SIZE - offset);
  61 @@ -256,7 +245,6 @@ retry:
  62                 done += len_str;
  63                 uaddr += len_str;
  64         } while ((len_str == len) && (done < count));
  65 -out:
  66         spin_unlock(&mm->page_table_lock);
  67         return done + 1;
  68  fault:
  69 @@ -325,12 +313,7 @@ retry:
  70                 }
  71
  72                 pfn_from = pte_pfn(*pte_from);
  73 -               if (!pfn_valid(pfn_from))
  74 -                       goto out;
  75                 pfn_to = pte_pfn(*pte_to);
  76 -               if (!pfn_valid(pfn_to))
  77 -                       goto out;
  78 -
  79                 offset_from = uaddr_from & (PAGE_SIZE-1);
  80                 offset_to = uaddr_from & (PAGE_SIZE-1);
  81                 offset_max = max(offset_from, offset_to);
  82 @@ -342,7 +325,6 @@ retry:
  83                 uaddr_from += size;
  84                 uaddr_to += size;
  85         } while (done < n);
  86 -out:
  87         spin_unlock(&mm->page_table_lock);
  88         return n - done;
  89  fault: