From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1fp6Y8-00080F-GZ for barebox@lists.infradead.org; Mon, 13 Aug 2018 06:41:58 +0000 Date: Mon, 13 Aug 2018 08:41:44 +0200 From: Sascha Hauer Message-ID: <20180813064144.7ocirutuvzltrrmn@pengutronix.de> References: <20180810185201.7677-1-andrew.smirnov@gmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20180810185201.7677-1-andrew.smirnov@gmail.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH] ARM: lib64: Properly handle unaligned addresses in string functions To: Andrey Smirnov Cc: barebox@lists.infradead.org On Fri, Aug 10, 2018 at 11:52:01AM -0700, Andrey Smirnov wrote: > Together FEC driver and parts of IP stack might end up trying to > memcpy() small chunks of memory from uncached (that is Device memory) > addresses that are not properly aligned, leading to data abort. > > To prevent such cases, add code to guard unaligned accesses and > redirect them to byte-wise implementations which do not have the above > problem. Please no. IMO this problem only shows that the FEC driver shouldn't use dma_alloc_coherent() to allocate its receive buffers, but instead should use dma_alloc + dma_sync_*. Sascha > > Signed-off-by: Andrey Smirnov > --- > arch/arm/lib64/string.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/arch/arm/lib64/string.c b/arch/arm/lib64/string.c > index cb2633152..1b04f4487 100644 > --- a/arch/arm/lib64/string.c > +++ b/arch/arm/lib64/string.c > @@ -5,9 +5,16 @@ > void *__arch_memset(void *dst, int c, __kernel_size_t size); > void *__arch_memcpy(void * dest, const void *src, size_t count); > > +static bool properly_aligned(const void *ptr) > +{ > + const unsigned long address = (unsigned long)ptr; > + > + return get_cr() & CR_M && IS_ALIGNED(address, 16); > +} > + > void *memset(void *dst, int c, __kernel_size_t size) > { > - if (likely(get_cr() & CR_M)) > + if (likely(properly_aligned(dst))) > return __arch_memset(dst, c, size); > > return __default_memset(dst, c, size); > @@ -15,7 +22,7 @@ void *memset(void *dst, int c, __kernel_size_t size) > > void *memcpy(void * dest, const void *src, size_t count) > { > - if (likely(get_cr() & CR_M)) > + if (likely(properly_aligned(dest) && properly_aligned(src))) > return __arch_memcpy(dest, src, count); > > return __default_memcpy(dest, src, count); > -- > 2.17.1 > > > _______________________________________________ > barebox mailing list > barebox@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/barebox > -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox