linux-kernel - Re: [PATCH v2 0/5] all: s390: make compat wrappers the generic solution

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Date:	Thu, 25 Feb 2016 09:54:09 +0100
From:	Heiko Carstens <heiko.carstens@...ibm.com>
To:	Yury Norov <ynorov@...iumnetworks.com>
Cc:	arnd@...db.de, catalin.marinas@....com,
	linux-kernel@...r.kernel.org, linux-s390@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-arch@...r.kernel.org,
	linux-doc@...r.kernel.org, Prasun.Kapoor@...iumnetworks.com,
	pinskia@...il.com, agraf@...e.de, broonie@...nel.org,
	joseph@...esourcery.com, christoph.muellner@...obroma-systems.com,
	Nathan_Lynch@...tor.com, klimov.linux@...il.com,
	bamvor.zhangjian@...wei.com
Subject: Re: [PATCH v2 0/5] all: s390: make compat wrappers the generic
 solution

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 <heiko.carstens@...ibm.com>