Re: Maturity of GRUB on powerpc/ppc64?

[Frank Scheiner]

On 09/26/2017 08:57 PM, Frank Scheiner wrote:
> I'll describe details maybe later this week. In short, it works similar 
> in general to what I described for the Power Mac G5 (11,2). On the 
> Xserve G4 I used it without separate partition for `/boot` without an 
> issue (the partition for `/` was formatted with EXT4 during the original 
> Wheezy installation on this machine). It cost me some time to find out 
> what was the correct setting to activate the serial console. By default 
> Grub uses a glass console, even if there is no graphics card installed. 
> But this is usually not an issue for the workstations.

As a follow-up to [1] but maybe better placed under the subject of this 
thread, the promised details for the Grub installation on an Xserve G4 
with Debian Sid.

The Xserve G4 originally had Debian Wheezy installed which was first 
upgraded to Debian Jessie and then to Debian Sid. To be able to 
successfully boot with the current Linux kernel 4.12.x:

1. I needed to blacklist the `rack-meter` module. It is loaded 
automatically by kernel 4.12.x of Debian Sid but not by 3.16.x of Debian 
Jessie - don't know why. But both kernels panic after it was loaded.

2. Because I couldn't successfully boot with kernel 4.12.x, I wanted to 
fall back to kernel 3.16.x to fix things, but this also didn't work out 
of the box, as the `/dev/disk` directory in the - possibly recreated - 
initrd of kernel 3.16.x did not contain a `by-uuid` directory, but the 
root FS was given by UUID in the kernel command line provided by yaboot. 
I don't know if this was done by Sid, Jessie or Wheezy originally. With 
a Debian installer CD-ROM I could "fix" things by using the actual `sd` 
device.

For the Grub installation I used the same approach as in [1] and not the 
`grub-install` command to rule out additional sources of errors:

# GRUB-IEEE1275 setup in Xserve G4 (1,2) #

## Install grub-ieee1275 ##

```
# apt install grub-ieee1275
```

## Full file list for grub image ##

Placed in `~/grub/`, copied from `/usr/lib/grub/powerpc-ieee1275` - this 
time in a more useful form for copy-and-paste:
```
archelp.mod bitmap.mod bitmap_scale.mod blocklist.mod boot.mod bufio.mod 
cat.mod cmp.mod configfile.mod cpio.mod crypto.mod datehook.mod date.mod 
datetime.mod disk.mod echo.mod elf.mod ext2.mod fat.mod font.mod 
fshelp.mod gettext.mod gfxmenu.mod gfxterm.mod gzio.mod halt.mod 
help.mod hexdump.mod hfs.mod hfsplus.mod ieee1275_fb.mod kernel.img 
linux.mod loadenv.mod loopback.mod lsmmap.mod ls.mod memdisk.mod 
memrw.mod minicmd.mod moddep.lst msdospart.mod normal.mod part_apple.mod 
part_msdos.mod parttool.mod probe.mod read.mod reboot.mod regexp.mod 
relocator.mod scsi.mod search_fs_file.mod search_fs_uuid.mod 
search_label.mod search.mod setjmp.mod sleep.mod suspend.mod 
terminal.mod test.mod trig.mod true.mod video_colors.mod video_fb.mod 
videoinfo.mod video.mod
```

## Partition table ##

```
~# mac-fdisk -l
/dev/sda
        #                    type name                  length   base 
 ( size )  system
/dev/sda1     Apple_partition_map Apple                     63 @ 1   ( 
31.5k)  Partition map
/dev/sda2         Apple_Bootstrap untitled                1954 @ 64 
(977.0k)  NewWorld bootblock
/dev/sda3         Apple_UNIX_SVR2 untitled           613027344 @ 2018 
(292.3G)  Linux native
/dev/sda4         Apple_UNIX_SVR2 swap                12113037 @ 
613029362 (  5.8G)  Linux swap
/dev/sda5              Apple_Free Extra                     49 @ 
625142399 ( 24.5k)  Free space

Block size=512, Number of Blocks=625142448
DeviceType=0x0, DeviceId=0x0
```

## Embedded config file ##

NOTICE: No separate partition for `/boot` used this time!

`~/grub/grub-embedded-config.cfg`
```
insmod serial
insmod terminal
insmod part_apple
insmod ext2

terminal_input serial_ieee1275/scca console
terminal_output serial_ieee1275/scca console

set root=(ieee1275/hd,apple3)
set prefix=(ieee1275/hd,apple3)/boot/grub

configfile /boot/grub/grub.cfg
```

## Actual config file ##

NOTICE: No separate partition for `/boot` used this time!

`/boot/grub/grub.cfg`
```
set root=(ieee1275/hd,apple3)

timeout=10
#default=0

menuentry "Debian GNU/Linux Sid (powerpc)" {
    linux /boot/vmlinux root=/dev/sda3 console=tty1 console=ttyPZ0,57600n8
    initrd /boot/initrd.img
}
```

## Command to create the grub image ##

```
~/grub# grub-mkimage -c ./grub-embedded-config.cfg -o ../grub.img -O 
powerpc-ieee1275 -d . -p '(ieee1275/hd,apple3)/boot/grub' *.mod
```

## Installation on HFS partition ##

This time with correct command and directory names (compared to [1]):
```
~# mount /dev/sda2 /mnt
~# cp grub.img /mnt/
~# sync
~# df -h
[...]
/dev/sda2       974K  852K  122K  88% /mnt
[...]
~# umount /mnt
```

Cheers,
Frank

[1]: https://lists.debian.org/debian-powerpc/2017/09/msg00034.html