persistant boot options on systems without ipmi

[hanetzer]

Unless I'm just dumb I don't think its possible to set autoboot options on systems which
do not do ipmi. I currently have a buildroot-built 'skiroot' for aarch64 (rk3399-gru-kevin)
which can boot gentoo on the emmc. However, I have to manually tell it to boot the entry
each time I boot it. Boot overrides inside the 'System configuration' menu of petitboot-nc
do not persist after reboots.

Using petitboot 1.10.3 and the following syslinux.cfg:

DEFAULT 5.0.9-gentoo

LABEL 5.0.9-gentoo
kernel /boot/vmlinuz-5.0.9-gentoo
append console=tty0 console=ttyS2,115200n8 earlyprintk=ttyS2,115200n8 init=/sbin/openrc-init root=/dev/mmcblk1p2 rootwait rw earlycon=uart8250,mmio32,0xff1a0000
initrd /boot/initramfs-5.0.9-gentoo.img

[hanetzer]

Ok a bit of research shows that on powerpc systems these params are stored in some form of nvram.
No such memory exists on my system, and no platform-independent way of storing this sort of thing
exists in mainline coreboot atm. So, I'm working on implementing a platform-uboot.c to use the
userspace tools from uboot (fw_printenv and fw_setenv) to store these params, and shrink the cbfs
in coreboot by a bit to store the params.

[sammj]

@hanetzer yep, on POWER boxes this is saved in NVRAM. fw_fooenv support would be great to have, if you have patches or questions feel free to post them on the mailing list! https://lists.ozlabs.org/listinfo/petitboot

[hanetzer]

@sammj ok, I've got a basic platform-uboot.c thrown together, sent it to the ml. Problem is, the
petitboot parameters which contain a ?, such as autoboot?, need to be escaped otherwise
the u-boot env gets corrupted. so instead of constructing a command like this;
fw_setenv autoboot? true we would need fw_setenv autoboot\? true, and I'm not sure how
I could achieve that based on the existing code.

[sammj]

How parameters are saved is implemented per-platform, so in your platform-uboot you could probably handle this by inserting escaping characters if needed in what you pass to fw_setenv etc.