From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Glass Date: Tue, 5 May 2020 12:41:44 -0600 Subject: [PATCH V2] mkimage: fit: Do not tail-pad fitImage with external data In-Reply-To: <20200505175022.GW12564@bill-the-cat> References: <20200501154026.79169-1-marex@denx.de> <20200504112749.GE12564@bill-the-cat> <20200505175022.GW12564@bill-the-cat> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Tom, On Tue, 5 May 2020 at 11:50, Tom Rini wrote: > > On Tue, May 05, 2020 at 06:39:58PM +0200, Marek Vasut wrote: > > On 5/5/20 6:37 PM, Alex Kiernan wrote: > > > On Tue, May 5, 2020 at 2:28 PM Marek Vasut wrote: > > >> > > >> On 5/5/20 3:22 PM, Alex Kiernan wrote: > > >>> On Mon, May 4, 2020 at 12:28 PM Tom Rini wrote: > > >>>> > > >>>> On Fri, May 01, 2020 at 05:40:25PM +0200, Marek Vasut wrote: > > >>>> > > >>>>> There is no reason to tail-pad fitImage with external data to 4-bytes, > > >>>>> while fitImage without external data does not have any such padding and > > >>>>> is often unaligned. DT spec also does not mandate any such padding. > > >>>>> > > >>>>> Moreover, the tail-pad fills the last few bytes with uninitialized data, > > >>>>> which could lead to a potential information leak. > > >>>>> > > >>>>> $ echo -n xy > /tmp/data ; \ > > >>>>> ./tools/mkimage -E -f auto -d /tmp/data /tmp/fitImage ; \ > > >>>>> hexdump -vC /tmp/fitImage | tail -n 3 > > >>>>> > > >>>>> before: > > >>>>> 00000260 61 2d 6f 66 66 73 65 74 00 64 61 74 61 2d 73 69 |a-offset.data-si| > > >>>>> 00000270 7a 65 00 00 78 79 64 64 |ze..xydd| > > >>>>> ^^ ^^ ^^ > > >>>>> after: > > >>>>> 00000260 61 2d 6f 66 66 73 65 74 00 64 61 74 61 2d 73 69 |a-offset.data-si| > > >>>>> 00000270 7a 65 00 78 79 |ze.xy| > > >>>>> > > >>>>> Signed-off-by: Marek Vasut > > >>>>> Reviewed-by: Simon Glass > > >>>>> Cc: Heinrich Schuchardt > > >>>>> Cc: Tom Rini > > >>>> > > >>>> Applied to u-boot/master, thanks! > > >>>> > > >>> > > >>> This breaks booting on my board (am3352, eMMC boot, FIT u-boot, > > >>> CONFIG_SPL_LOAD_FIT). Not got any useful diagnostics - if I boot it > > >>> from eMMC I get nothing at all on the console, if I boot over ymodem > > >>> it stalls at 420k, before continuing to 460k. My guess is there's some > > >>> error going to the console at the 420k mark, but obviously it's lost > > >>> in the ymodem... I have two DTBs in the FIT image, 420k would about > > >>> align to the point between them. > > >> > > >> My bet would be on some padding / unaligned access problem that this > > >> patch uncovered. Can you take a look ? > > > > > > Seems plausible. With this change my external data starts at 0x483 and > > > everything after it is non-aligned: > > > > Should the beginning of external data be aligned ? > > If in U-Boot we revert e8c2d25845c72c7202a628a97d45e31beea40668 does the > problem go away? If so, that's not a fix outright, it means we need to > dig back in to the libfdt thread and find the "make this work without > killing performance everywhere all the time" option. If it is a device tree, it must be 32-bit aligned. But Marek's patch affects the FIT image itself, so I am not sure what would go after that. Regards, Simon