[U-Boot] [PATCH] x86/bootm: fix compressed image boot

[Bin Meng]

Hi Hannes,

On Thu, Oct 11, 2018 at 2:41 PM Hannes Schmelzer <hannes at schmelzer.or.at> wrote:
>
>
> On 11.10.2018 08:01, Bin Meng wrote:
> > Hi Hannes,
> Hi Bing,
> thanks for very quick response on this.
> >
> > On Thu, Oct 11, 2018 at 1:45 PM Hannes Schmelzer
> > <hannes.schmelzer at br-automation.com> wrote:
> >> If we're booting some u-boot module with compressed payload, we have to
> >> use the pointer where the image really has been loaded (unzipped) to
> >> instead the pointer to the payload of the u-boot module.
> >>
> >> Signed-off-by: Hannes Schmelzer <hannes.schmelzer at br-automation.com>
> >> ---
> >>
> >>   arch/x86/lib/bootm.c | 4 ++--
> >>   1 file changed, 2 insertions(+), 2 deletions(-)
> >>
> > Can you describe with what reproduce steps current codes are failing? thanks!
> The boot of a u-boot module with bootm walks like this:
>
> => bootm ${loadaddr} ${ramdisk} ${fdtcontroladdr}
> this leads to call (coming through cmd/bootm.c) to "do_bootm_states".
> The task of this "do_bootm_states" is to find out what todo with the
> provided image (u-boot module),
> is it compressed or not, which kind of os should be booted, ...
>
> So, for doing this work, "bootm_decomp_image" is called,
> this function uses the image-header for finding out the compression
> method and does decompress the real payload to some location.
>
> bootm_os_load moves on and finds out that some compressed linux payload
> shall be booted.
> So the "do_bootm_linux" and finally "boot_prep_linux" from lib/x86,
> since wer'e actually running on a x86 machine, is called.
>
> This function makes the assumption that the bootable binary is directly
> the payload of the u-boot module,
> ignoring the work done by "bootm_decomp_image" during the step before
> and tries to boot directly in my case a gzip binary.
>
> This is wrong.
>

Thanks for the explanation. This patch looks good to me.

However I was unable to proceed some testing to verify this.

When I use 'bootm' to boot a uImage with uncompressed bzImage, I simply get:

=> bootm 2000000 3000000
## Booting kernel from Legacy Image at 02000000 ...
   Image Name:   linux
   Created:      2018-11-20  15:23:19 UTC
   Image Type:   Intel x86 Linux Kernel Image (uncompressed)
   Data Size:    7716768 Bytes = 7.4 MiB
   Load Address: 01000000
   Entry Point:  01000000
   Verifying Checksum ... OK
Could not find a valid setup.bin for x86

It looks the error message comes from boot_get_setup() which expects
bootm payload is of FIT format. However this patch expects a uImage
with legacy format (images->legacy_hdr_valid == true).

Can you please post your complete instructions, including how to
create uImage for U-Boot's bootm work for legacy booting?

Regards,
Bin