From mboxrd@z Thu Jan  1 00:00:00 1970
From: linux@arm.linux.org.uk (Russell King - ARM Linux)
Date: Tue, 29 Oct 2013 18:04:14 +0000
Subject: [PATCH] Make the 32-bit ARM get_user() and put_user() work for
 16-bit quantities
In-Reply-To: <1383065529-20001-1-git-send-email-wcohen@redhat.com>
References: <1383065529-20001-1-git-send-email-wcohen@redhat.com>
Message-ID: <20131029180414.GS16735@n2100.arm.linux.org.uk>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Tue, Oct 29, 2013 at 12:52:09PM -0400, William Cohen wrote:
> The 32-bit ARM does not have instructions to perform 16-bit loads or
> stores.  The __get_user_asm_half and __put_user_asm_half macros
> sythesize those operations.  However, in most cases the pointers
> passed into these macros are pointers to 16-bit types and the pointer
> arithmetic will end up pointing at the next 16-bit quantity rather
> than the second half (byte) of the 16-bit quantity.  The macros need
> to explicitly typecast the pointers as pointers to 8-bit quantities to
> make the pointer arithmetic work out properly.

NAK.

Nothing should be making use of these macros other than the other
macros in that file; these are implementation specific helper macros.
There, the address passed as __gu_addr and __pu_addr is an 'unsigned
long' quantity, so there is no concern about pointer arithmetic; they
do not take pointers.