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 marex@denx.de 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 trini@konsulko.com 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 marex@denx.de wrote: >>>>>>>> >>>>>>>> On 5/5/20 3:22 PM, Alex Kiernan wrote: >>>>>>>>> On Mon, May 4, 2020 at 12:28 PM Tom Rini trini@konsulko.com 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 marex@denx.de >>>>>>>>>>> Reviewed-by: Simon Glass sjg@chromium.org >>>>>>>>>>> Cc: Heinrich Schuchardt xypron.glpk@gmx.de >>>>>>>>>>> Cc: Tom Rini trini@konsulko.com >>>>>>>>>> >>>>>>>>>> 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?