From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Date: Wed, 6 May 2020 18:35:52 +0200 Subject: [PATCH V2] mkimage: fit: Do not tail-pad fitImage with external data In-Reply-To: <20200506163334.GP12564@bill-the-cat> References: <20200506134857.GE12564@bill-the-cat> <20200506142754.GH12564@bill-the-cat> <04369d83-daef-03c3-7a9e-7a6c83f9a5a3@denx.de> <20200506143724.GI12564@bill-the-cat> <04cb1a3b-ec71-9ce1-f0cd-9d4ddae57010@denx.de> <20200506160447.GO12564@bill-the-cat> <2ed78efa-9ef2-06f5-20c3-767e9113603f@denx.de> <20200506163334.GP12564@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 On 5/6/20 6:33 PM, Tom Rini wrote: > On Wed, May 06, 2020 at 06:17:47PM +0200, Marek Vasut wrote: >> On 5/6/20 6:04 PM, Tom Rini wrote: >>> On Wed, May 06, 2020 at 05:52:45PM +0200, Marek Vasut wrote: >>>> On 5/6/20 5:43 PM, Alex Kiernan wrote: >>>>> On Wed, May 6, 2020 at 3:41 PM Marek Vasut wrote: >>>>>> >>>>>> On 5/6/20 4:37 PM, Tom Rini wrote: >>>>>>> On Wed, May 06, 2020 at 04:33:37PM +0200, Marek Vasut wrote: >>>>>>>> On 5/6/20 4:27 PM, Tom Rini wrote: >>>>>>>>> On Wed, May 06, 2020 at 04:17:35PM +0200, Marek Vasut wrote: >>>>>>>>>> On 5/6/20 3:48 PM, Tom Rini wrote: >>>>>>>>>>> On Tue, May 05, 2020 at 11:17:19PM +0200, Michael Walle wrote: >>>>>>>>>>>> Hi all, >>>>>>>>>>>> >>>>>>>>>>>> Am 2020-05-05 20:41, schrieb Simon Glass: >>>>>>>>>>>>> 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. >>>>>>>>>>>> >>>>>>>>>>>> This commit actually breaks my board too (which I was just about to send >>>>>>>>>>>> upstream, but realized it was broken). >>>>>>>>>>>> >>>>>>>>>>>> Said board uses SPL and main U-Boot. SPL runs fine and main u-boot doesn't >>>>>>>>>>>> output anything. The only difference which I found is that fit-dtb.blob is >>>>>>>>>>>> 2 bytes shorter. And the content is shifted by one byte although >>>>>>>>>>>> data-offset is the same. Strange. In the non-working case, the inner >>>>>>>>>>>> FDT magic isn't 4 byte aligned. >>>>>>>>>>>> >>>>>>>>>>>> You can find the two fit-dtb.blobs here: >>>>>>>>>>>> >>>>>>>>>>>> https://walle.cc/u-boot/fit-dtb.blob.working >>>>>>>>>>>> https://walle.cc/u-boot/fit-dtb.blob.non-working >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> Reverting e8c2d25845c72c7202a628a97d45e31beea40668 doesn't help (I might >>>>>>>>>>>> reverted it the wrong way, there is actually a conflict). >>>>>>>>>>>> >>>>>>>>>>>> I'll dig deeper into that tomorrow, but maybe you have some pointers where >>>>>>>>>>>> to look. >>>>>>>>>>>> >>>>>>>>>>>> For reference you can find the current patch here: >>>>>>>>>>>> https://github.com/mwalle/u-boot/tree/sl28-upstream >>>>>>>>>>> >>>>>>>>>>> I think we have a few things to fix here. Marek's patch is breaking >>>>>>>>>>> things and needs to be reverted. But it's showing a few underlying >>>>>>>>>>> problems that need to be fixed too: >>>>>>>>>>> - fit_extract_data() needs to use calloc() not malloc() so that we don't >>>>>>>>>>> leak random data. >>>>>>>>>>> - We need to 8-byte alignment on the external data. That's the >>>>>>>>>>> requirement for Linux for device trees on both 32 and 64bit arm. >>>>>>>>>>> Atish, does RISC-V require more than that? I don't see it in Linux's >>>>>>>>>>> Documentation/riscv/boot-image-header.rst (and there's no booting.rst >>>>>>>>>>> file like arm/arm64). >>>>>>>>>> >>>>>>>>>> Why 8-byte alignment ? The external data are copied into the target >>>>>>>>>> location, so why do they need to be padded in any way? >>>>>>>>> >>>>>>>>> The start of the external data needs the alignment, to be clearer. >>>>>>>> >>>>>>>> Why ? >>>>>>> >>>>>>> Given that things which end up in external data have alignment >>>>>>> requirements, we need to align and meet those requirements. And I noted >>>>>>> why 8 above. >>>>>> >>>>>> If you end up with external data, then you need to move those blobs into >>>>>> their target location anyway. That's what you specify in the load = <> >>>>>> property in the .its . >>>>>> >>>>> >>>>> Just reading common/spl/spl_fit.c, I think that'll try and parse in >>>>> situ, rather than relocating it? >>>> >>>> And is that correct or is that the same problem as we have on arm64 with >>>> fitImage and fdt_high=-1 ? I think it's the later. >>> >>> I'm not sure that it is. Can we easily/safely memmove the data to be >>> aligned? Is that really a better option in this case than ensuring >>> alignment within the file? >> >> Can't we use the new mkimage -B option to enforce the alignment IFF and >> only IFF it is required ? > > Perhaps. But.. > >> Then we can enforce it separately for 32bit >> and 64bit platforms to 4 and 8 bytes respectively even. > > It's 8 bytes for both. It's possible that Linux doesn't hard fail if > you only do 4 byte alignment but the documented requirement is 8, for > arm32. With Linux you usually need to move the kernel anyway, no ? It's 2 MiB for arm64 for example. And what you usually parse in-place would be the DT then.