userfaultfd: UFFDIO_COPY and UFFDIO_ZEROPAGE

[firefly-linux-kernel-4.4.55.git] / fs / userfaultfd.c

diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index febbd2b165dfcc2923e559cbb3b5287c8f580ca8..5f11678907d5d90427f089a3c0e649c4ee2444d1 100644 (file)
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -983,6 +983,96 @@ out:
        return ret;
 }
 
+static int userfaultfd_copy(struct userfaultfd_ctx *ctx,
+                           unsigned long arg)
+{
+       __s64 ret;
+       struct uffdio_copy uffdio_copy;
+       struct uffdio_copy __user *user_uffdio_copy;
+       struct userfaultfd_wake_range range;
+
+       user_uffdio_copy = (struct uffdio_copy __user *) arg;
+
+       ret = -EFAULT;
+       if (copy_from_user(&uffdio_copy, user_uffdio_copy,
+                          /* don't copy "copy" last field */
+                          sizeof(uffdio_copy)-sizeof(__s64)))
+               goto out;
+
+       ret = validate_range(ctx->mm, uffdio_copy.dst, uffdio_copy.len);
+       if (ret)
+               goto out;
+       /*
+        * double check for wraparound just in case. copy_from_user()
+        * will later check uffdio_copy.src + uffdio_copy.len to fit
+        * in the userland range.
+        */
+       ret = -EINVAL;
+       if (uffdio_copy.src + uffdio_copy.len <= uffdio_copy.src)
+               goto out;
+       if (uffdio_copy.mode & ~UFFDIO_COPY_MODE_DONTWAKE)
+               goto out;
+
+       ret = mcopy_atomic(ctx->mm, uffdio_copy.dst, uffdio_copy.src,
+                          uffdio_copy.len);
+       if (unlikely(put_user(ret, &user_uffdio_copy->copy)))
+               return -EFAULT;
+       if (ret < 0)
+               goto out;
+       BUG_ON(!ret);
+       /* len == 0 would wake all */
+       range.len = ret;
+       if (!(uffdio_copy.mode & UFFDIO_COPY_MODE_DONTWAKE)) {
+               range.start = uffdio_copy.dst;
+               wake_userfault(ctx, &range);
+       }
+       ret = range.len == uffdio_copy.len ? 0 : -EAGAIN;
+out:
+       return ret;
+}
+
+static int userfaultfd_zeropage(struct userfaultfd_ctx *ctx,
+                               unsigned long arg)
+{
+       __s64 ret;
+       struct uffdio_zeropage uffdio_zeropage;
+       struct uffdio_zeropage __user *user_uffdio_zeropage;
+       struct userfaultfd_wake_range range;
+
+       user_uffdio_zeropage = (struct uffdio_zeropage __user *) arg;
+
+       ret = -EFAULT;
+       if (copy_from_user(&uffdio_zeropage, user_uffdio_zeropage,
+                          /* don't copy "zeropage" last field */
+                          sizeof(uffdio_zeropage)-sizeof(__s64)))
+               goto out;
+
+       ret = validate_range(ctx->mm, uffdio_zeropage.range.start,
+                            uffdio_zeropage.range.len);
+       if (ret)
+               goto out;
+       ret = -EINVAL;
+       if (uffdio_zeropage.mode & ~UFFDIO_ZEROPAGE_MODE_DONTWAKE)
+               goto out;
+
+       ret = mfill_zeropage(ctx->mm, uffdio_zeropage.range.start,
+                            uffdio_zeropage.range.len);
+       if (unlikely(put_user(ret, &user_uffdio_zeropage->zeropage)))
+               return -EFAULT;
+       if (ret < 0)
+               goto out;
+       /* len == 0 would wake all */
+       BUG_ON(!ret);
+       range.len = ret;
+       if (!(uffdio_zeropage.mode & UFFDIO_ZEROPAGE_MODE_DONTWAKE)) {
+               range.start = uffdio_zeropage.range.start;
+               wake_userfault(ctx, &range);
+       }
+       ret = range.len == uffdio_zeropage.range.len ? 0 : -EAGAIN;
+out:
+       return ret;
+}
+
 /*
  * userland asks for a certain API version and we return which bits
  * and ioctl commands are implemented in this kernel for such API
@@ -1038,6 +1128,12 @@ static long userfaultfd_ioctl(struct file *file, unsigned cmd,
        case UFFDIO_WAKE:
                ret = userfaultfd_wake(ctx, arg);
                break;
+       case UFFDIO_COPY:
+               ret = userfaultfd_copy(ctx, arg);
+               break;
+       case UFFDIO_ZEROPAGE:
+               ret = userfaultfd_zeropage(ctx, arg);
+               break;
        }
        return ret;
 }