[U-Boot] [PATCH] Enable thumb build to reduce build size of u-boot.kwb.

[Chris Packham]

On Mon, 4 Jun 2018, 9:23 AM Vagrant Cascadian, <vagrant at debian.org> wrote:

> On 2018-06-03, Chris Packham wrote:
> > On Mon, 4 Jun 2018, 7:39 AM Vagrant Cascadian, <vagrant at debian.org>
> wrote:
> >
> >> Without this, u-boot.kwb overlaps where the u-boot environment is
> >> stored, and updating the environment can break u-boot and vice versa.
> >>
> >>   https://bugs.debian.org/897671
> >>   https://lists.denx.de/pipermail/u-boot/2018-May/327497.html
> >>
> >> Signed-off-by: Vagrant Cascadian <vagrant at debian.org>
> >> ---
> >>
> >>  configs/sheevaplug_defconfig | 1 +
> >>  1 file changed, 1 insertion(+)
> >>
> >> diff --git a/configs/sheevaplug_defconfig b/configs/sheevaplug_defconfig
> >> index 608e05e64e..d77d198f18 100644
> >> --- a/configs/sheevaplug_defconfig
> >> +++ b/configs/sheevaplug_defconfig
> >> @@ -36,3 +36,4 @@ CONFIG_USB=y
> >>  CONFIG_USB_EHCI_HCD=y
> >>  CONFIG_USB_STORAGE=y
> >>  CONFIG_LZMA=y
> >> +CONFIG_SYS_THUMB_BUILD=y
> >> --
> >
> >
> > Stefan sent a patch to move the environment for openrd is it worth doing
> > that instead?
>
> Moving the environment breaks compatibility with older saved
> environments, so seems like something that should be done as a last
> resort, in my opinion, since upgrading the bootloader can result in an
> unbootable system if they depend on the environment.
>
> Enabling THUMB significantly reduced the size of the image, which should
> reduce having to play whack-a-mole every few releases as u-boot
> inevitably tends to grow in size over time... at least for a while.
>

Agreed. The DM changes will likely increase the size at least until
everything is converted.

> Also isn't there an option to enforce a build size limit so that we notice
> > when we've expanded too far? That's how we noticed the problem for
> openrd.
>
> There is, and would obviously be a good thing to add.
>
> I also have very limited time to work on support for boards I don't have
> the ability to test myself. Essentially, relaying this bug due to a bug
> report from a Debian user.
>

Ok I'll see if i can take a look for kirkwood boards that don't already
have this in place.

>