On Sat, May 14, 2016 at 06:03:52PM +0300, Yury Norov wrote:

+SYSCALL_DEFINE6(mmap2, unsigned long, addr, unsigned long, len,
+       unsigned long, prot, unsigned long, flags, unsigned long, fd,
+       unsigned long, pgoff)

To avoid the types confusion we could add __SC_WRAP to mmap2 in unistd.h
and use COMPAT_SYSCALL_DEFINE6 here (together with compat_ptr_t etc.).

+{
+       if (pgoff & (~PAGE_MASK >> 12))
+               return -EINVAL;
+
+       return sys_mmap_pgoff((compat_uptr_t) addr, (compat_size_t) len,
+		       (int) prot, (int) flags, (int) fd,
+		       pgoff >> (PAGE_SHIFT-12));

Then we wouldn't need the explicit casting here.

+}
+
+COMPAT_SYSCALL_DEFINE4(pread64, unsigned int, fd, compat_uptr_t __user *, ubuf,
+		       compat_size_t, count, off_t, offset)
+{
+	return sys_pread64(fd, (char *) ubuf, count, offset);
+}
+
+COMPAT_SYSCALL_DEFINE4(pwrite64, unsigned int, fd, compat_uptr_t __user *, ubuf,
+		       compat_size_t, count, off_t, offset)
+{
+	return sys_pwrite64(fd, (char *) ubuf, count, offset);

Nitpick: no space between cast type and variable name: (char *)ubuf, ...

We can also make these functions static as they are not used outside
this file.

-- 
Catalin