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 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?
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.