Re: Old platforms never die, was Re: Old platforms: bring out your dead

From: Rob Landley <rob@landley.net>
To: Finn Thain <fthain@telegraphics.com.au>,
	John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Gerhard Pircher <gerhard_pircher@gmx.net>,
	Arnd Bergmann <arnd@arndb.de>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-m68k <linux-m68k@lists.linux-m68k.org>,
	Sparc kernel list <sparclinux@vger.kernel.org>,
	Linux-sh list <linux-sh@vger.kernel.org>
Subject: Re: Old platforms never die, was Re: Old platforms: bring out your dead
Date: Sat, 16 Jan 2021 00:54:22 -0600	[thread overview]
Message-ID: <897dbd50-ce42-8fdb-8777-fab08185e324@landley.net> (raw)
In-Reply-To: <alpine.LNX.2.23.453.2101131035500.6@nippy.intranet>

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On 1/12/21 6:12 PM, Finn Thain wrote:
> If you're a museum interested in cultural artifacts from decades past, or 
> if you're a business doing data recovery, you're going to need to operate 
> those platforms.

Or if you're camping patent expirations and want to be able to point at prior
art for new hardware development WITHOUT a legal team big enough to have its own
office building.

> Once removed from mainline Linux, a port becomes basically frozen, and may 
> not be compatible with future emulators, which are a moving target. I say 
> that because last year I fixed bugs in Linux/m68k that made it incomatible 
> with recent QEMU releases (it was only compatible with old QEMU releases).

Speaking of which, my qemu m68k system has failed to boot ever since commit:

commit f93bfeb55255bddaa16597e187a99ae6131b964a
Author: Finn Thain <fthain@telegraphics.com.au>
Date:   Sun Jun 28 14:23:12 2020 +1000

    macintosh/via-macii: Poll the device most likely to respond

    Poll the most recently polled device by default, rather than the lowest
    device address that happens to be enabled in autopoll_devs. This improves
    input latency. Re-use macii_queue_poll() rather than duplicate that logic.
    This eliminates a static struct and function.

It hangs in a cpu-eating loop after "random: crng init done". Miniconfig
attached, the qemu invocation is:

qemu-system-m68k -M q800 -nographic -no-reboot -m 256 -kernel vmlinux \
  -initrd cpio.gz -append "panic=1 HOST=m68k console=ttyS0

Rob

P.S. This is the toybox "make root" m68k target from
https://github.com/landley/toybox/blob/master/scripts/mkroot.sh#L171 if that's
useful to know. It doesn't get to the root filesystem and the build just creates
that miniconfig and runs it as the comments say...

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# make ARCH=m68k allnoconfig KCONFIG_ALLCONFIG=m68k.miniconf
# make ARCH=m68k -j $(nproc)
# boot vmlinux

# CONFIG_EMBEDDED is not set
# architecture independent
CONFIG_BINFMT_ELF=y
CONFIG_BINFMT_SCRIPT=y
CONFIG_NO_HZ=y
CONFIG_HIGH_RES_TIMERS=y
CONFIG_BLK_DEV=y
CONFIG_BLK_DEV_INITRD=y
CONFIG_RD_GZIP=y
CONFIG_BLK_DEV_LOOP=y
CONFIG_EXT4_FS=y
CONFIG_EXT4_USE_FOR_EXT2=y
CONFIG_VFAT_FS=y
CONFIG_FAT_DEFAULT_UTF8=y
CONFIG_MISC_FILESYSTEMS=y
CONFIG_SQUASHFS=y
CONFIG_SQUASHFS_XATTR=y
CONFIG_SQUASHFS_ZLIB=y
CONFIG_DEVTMPFS=y
CONFIG_DEVTMPFS_MOUNT=y
CONFIG_TMPFS=y
CONFIG_TMPFS_POSIX_ACL=y
CONFIG_NET=y
CONFIG_PACKET=y
CONFIG_UNIX=y
CONFIG_INET=y
CONFIG_IPV6=y
CONFIG_NETDEVICES=y
CONFIG_NET_CORE=y
CONFIG_NETCONSOLE=y
CONFIG_ETHERNET=y
CONFIG_COMPAT_32BIT_TIME=y
CONFIG_EARLY_PRINTK=y
CONFIG_IKCONFIG=y
CONFIG_IKCONFIG_PROC=y

# architecture specific
CONFIG_MMU=y
CONFIG_M68040=y
CONFIG_M68KFPU_EMU=y
CONFIG_MAC=y
CONFIG_SCSI_MAC_ESP=y
CONFIG_MACINTOSH_DRIVERS=y
CONFIG_ADB=y
CONFIG_ADB_MACII=y
CONFIG_NET_CORE=y
CONFIG_MACSONIC=y
CONFIG_SERIAL_PMACZILOG=y
CONFIG_SERIAL_PMACZILOG_TTYS=y
CONFIG_SERIAL_PMACZILOG_CONSOLE=y