On Wed, Feb 24, 2016 at 09:34:09PM +0300, Yury Norov wrote:

The problem that makes us use wrappers is that some compat
architectures allows user code to access top halves of registers.
This is not a problem for syscalls that are already handled by compat
code, or for that who has types of the same size in kernel and
userspace. In case of s390 and lp64/ilp32 the problem is in pointer
types, long, unsigned long.

S390 folks already have the solution for it. In this patchset,
it is turned to be general, as arm64/ilp32 needs it too.

This patchset is created as the part of the work of enabling arm64
with ILP32 user mode. See details here:
http://thread.gmane.org/gmane.linux.kernel/2126946

This is the implementation of one of two possible approaches. First
one defines new syscall handler declaration macro, that creates both compat and
non-compat handlers, see [1]. This one declares all wrappers in separated file
kernel/compat_wrapper.c

Build-tested on s390.

[1] http://www.spinics.net/lists/linux-s390/msg11593.html

Yury Norov (5):
  all: syscall wrappers: add documentation
  all: introduce COMPAT_WRAPPER option and enable it for s390
  all: s390: move wrapper infrastructure to generic headers
  all: s390: move compat_wrappers.c from arch/s390/kernel to kernel/
  all: wrap needed syscalls in generic unistd

Looks good to me. You may consider the possible changes I sent as reply to
some of your patches.
However from an s390 point of view:

Acked-by: Heiko Carstens <redacted>