bfin-proc-mem.patch

   1 --- a/mm/memory.c
   2 +++ b/mm/memory.c
   3 @@ -2505,3 +2505,56 @@ #endif
   4  }
   5
   6  #endif /* __HAVE_ARCH_GATE_AREA */
   7 +
   8 +/*
   9 + * Access another process' address space.
  10 + * Source/target buffer must be kernel space,
  11 + * Do not walk the page table directly, use get_user_pages
  12 + */
  13 +int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
  14 +{
  15 +       struct mm_struct *mm;
  16 +       struct vm_area_struct *vma;
  17 +       struct page *page;
  18 +       void *old_buf = buf;
  19 +
  20 +       mm = get_task_mm(tsk);
  21 +       if (!mm)
  22 +               return 0;
  23 +
  24 +       down_read(&mm->mmap_sem);
  25 +       /* ignore errors, just check how much was sucessfully transfered */
  26 +       while (len) {
  27 +               int bytes, ret, offset;
  28 +               void *maddr;
  29 +
  30 +               ret = get_user_pages(tsk, mm, addr, 1,
  31 +                               write, 1, &page, &vma);
  32 +               if (ret <= 0)
  33 +                       break;
  34 +
  35 +               bytes = len;
  36 +               offset = addr & (PAGE_SIZE-1);
  37 +               if (bytes > PAGE_SIZE-offset)
  38 +                       bytes = PAGE_SIZE-offset;
  39 +
  40 +               maddr = kmap(page);
  41 +               if (write) {
  42 +                       copy_to_user_page(vma, page, addr,
  43 +                                         maddr + offset, buf, bytes);
  44 +                       set_page_dirty_lock(page);
  45 +               } else {
  46 +                       copy_from_user_page(vma, page, addr,
  47 +                                           buf, maddr + offset, bytes);
  48 +               }
  49 +               kunmap(page);
  50 +               page_cache_release(page);
  51 +               len -= bytes;
  52 +               buf += bytes;
  53 +               addr += bytes;
  54 +       }
  55 +       up_read(&mm->mmap_sem);
  56 +       mmput(mm);
  57 +
  58 +       return buf - old_buf;
  59 +}
  60 --- a/mm/nommu.c
  61 +++ b/mm/nommu.c
  62 @@ -1206,3 +1206,51 @@ struct page *filemap_nopage(struct vm_ar
  63         BUG();
  64         return NULL;
  65  }
  66 +
  67 +/*
  68 + * Access another process' address space.
  69 + * - source/target buffer must be kernel space
  70 + */
  71 +int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
  72 +{
  73 +       struct vm_list_struct *vml;
  74 +       struct vm_area_struct *vma;
  75 +       struct mm_struct *mm;
  76 +printk("!!! OH YEAH\n");
  77 +       if (addr + len < addr)
  78 +               return 0;
  79 +
  80 +       mm = get_task_mm(tsk);
  81 +       if (!mm)
  82 +               return 0;
  83 +
  84 +       down_read(&mm->mmap_sem);
  85 +
  86 +       /* the access must start within one of the target process's mappings */
  87 +       for (vml = mm->context.vmlist; vml; vml = vml->next) {
  88 +               if (addr >= vml->vma->vm_start && addr < vml->vma->vm_end)
  89 +                       break;
  90 +       }
  91 +
  92 +       if (vml) {
  93 +               vma = vml->vma;
  94 +
  95 +               /* don't overrun this mapping */
  96 +               if (addr + len >= vma->vm_end)
  97 +                       len = vma->vm_end - addr;
  98 +
  99 +               /* only read or write mappings where it is permitted */
 100 +               if (write && vma->vm_flags & VM_WRITE)
 101 +                       len -= copy_to_user((void *) addr, buf, len);
 102 +               else if (!write && vma->vm_flags & VM_READ)
 103 +                       len -= copy_from_user(buf, (void *) addr, len);
 104 +               else
 105 +                       len = 0;
 106 +       } else {
 107 +               len = 0;
 108 +       }
 109 +
 110 +       up_read(&mm->mmap_sem);
 111 +       mmput(mm);
 112 +       return len;
 113 +}