On Wed, 7 Jul 2021, Mark Cave-Ayland wrote: > > You don't need a rootfs to see the jazzsonic driver messages. But if > > you still want one, you could try the mipsel builds from these distros > > (not the 64-bit ones): > > > > https://ftp.jaist.ac.jp/pub/Linux/Gentoo/experimental/mips/stages/
When I tried following my own advice I ran into ABI compatibility problems. It looks like my kernel build doesn't like those binaries, but maybe it's a limitation of the Magnum CPU... ... Run /bin/sh as init process request_module: kmod_concurrent_max (0) close to 0 (max_modprobes: 50), for module binfmt-464c, throttling... request_module: modprobe binfmt-464c cannot be processed, kmod busy with 50 threads for more than 5 seconds now Kernel panic - not syncing: Requested init /bin/sh failed (error -8). > > https://landley.net/aboriginal/downloads/binaries/ The binaries from Aboriginal Linux work okay (that is, rootfs.cpio.gz found in system-image-mipsel.tar.gz). I got a shell prompt using init=/bin/sh but there's no networking support in this minimal busybox build unfortunately. Those binaries have the same ABI as the ones in my busybox build: $ file busybox busybox: ELF 32-bit LSB executable, MIPS, MIPS-I version 1 (SYSV), statically linked, stripped Whereas, Debian/mipsel binaries (like the Gentoo ones) look like this: $ file busybox busybox: ELF 32-bit LSB pie executable, MIPS, MIPS32 rel2 version 1 (SYSV), dynamically linked, interpreter /lib/ld.so.1, for GNU/Linux 3.2.0, BuildID[sha1]=febe1809f2ad8dacb067dfd74505b19c6c69ba65, stripped Eventually I found this page, https://wiki.debian.org/MIPSPort which explains that the Debian/mipsel port switched ABI between Debian 8 and Debian 9. Unfortunately, the Debian 7 and 8 installer ISO images have no initrd so they are no use. I got them from this archive: https://cdimage.debian.org/cdimage/archive/ Anyway, the Debian 8 binaries look like this, and they work too: # file bin/dash bin/dash: ELF 32-bit LSB shared object, MIPS, MIPS-II version 1 (SYSV), dynamically linked, interpreter /lib/ld.so.1, for GNU/Linux 2.6.32, BuildID[sha1]=44f7c1d61d9941db2b1de5dd9629c99e06c30ea8, stripped > > That's true, but then this wouldn't enable testing of Phil's proposed > CRC changes. Having a simple shell with ping and wget/curl is a real > help here. > To generate network traffic you can get the kernel to configure the NIC over DHCP but that does require a different kernel config (see below). > > > If you can provide me with a link to your vmlinux and rootfs with > > > busybox or similar in it, I can take a look to see what is happening > > > here. Otherwise it's almost impossible for me to understand and > > > debug the problem you are seeing on your setup. > > > > > > > Uploading kernels is a hassle (for me) as it brings a trust question > > and requires a file hosting service. I really should use PGP and > > organise a web of trust but that's very difficult given my rural > > location. > > Given that these are only running in a VM I'm not too worried about > trust. Well, untrusted images are okay as long as we are talking about debugging QEMU issues that are not exploitable... With a bit of searching I was able to find a Debian/mipsel 8 rootfs at https://github.com/jubinson/debian-rootfs I can't vouch for it though. It appears to be a page of links to tar files in someone's dropbox. $ sha256sum mipsel-rootfs-20170318T103423Z.tar.gz e6ed1871b29317c85170a07621966a013951ced1c5fb8d679b7519996b803fe8 mipsel-rootfs-20170318T103423Z.tar.gz > I also have a VPS with scp access that I could temporarily grant you > access via an SSH public key if that helps? > Thanks for the offer. But that wouldn't help anyone else reading this. In anycase, I wanted to see whether a real distro could be used. So my plan was to cross-compile a Linux kernel and debootstrap a Debian/mipsel rootfs disk image. The first stage of a debootstrap installation runs on the host... sudo -s truncate -s 1G jessie-mipsel.img mke2fs jessie-mipsel.img mount -o loop jessie-mipsel.img /mnt wget -q -O- https://ftp-master.debian.org/keys/release-8.asc | gpg --import --no-default-keyring --keyring ./debian-release-8.gpg debootstrap --keyring=./debian-release-8.gpg --foreign --arch=mipsel jessie /mnt http://archive.debian.org/debian/ umount /mnt exit git clone git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git cd linux git checkout linux-5.10.y make ARCH=mips CROSS_COMPILE=mipsel-linux-gnu- clean jazz_defconfig scripts/config -d IPV6 -d WIRELESS -d WLAN -d DEBUG_KERNEL -d EXPERT -d CC_OPTIMIZE_FOR_PERFORMANCE -e CC_OPTIMIZE_FOR_SIZE -e ISO9660_FS -m EXT3_FS -e NFS_FS -e IP_PNP -e ROOT_NFS -e NFS_V2 -e IP_PNP_DHCP -e CMDLINE_BOOL -e MIPS_CMDLINE_BUILTIN_EXTEND --set-str CMDLINE "console=ttyS0 root=/dev/nfs rw" make ARCH=mips CROSS_COMPILE=mipsel-linux-gnu- olddefconfig vmlinux mkisofs -o vmlinux.iso -J -iso-level 3 vmlinux qemu-system-mips64el -M magnum -L . -drive if=scsi,unit=0,format=raw,file=jessie-mipsel.img -drive if=scsi,unit=2,readonly=y,media=cdrom,format=raw,file=vmlinux.iso -drive if=scsi,unit=4,readonly=y,media=cdrom,format=raw,file=NetBSD-9.2-arc.iso -global ds1225y.filename=nvram -serial mon:stdio -serial null -net nic,model=dp83932,addr=00:00:00:aa:bb:cc -net bridge Actions: Start Windows NT -> Run a program Run setup scsi(0)cdrom(4)fdisk(0)boot scsi(0)cdrom(2)fdisk(0)vmlinux root=/dev/sda init=/bin/sh This boots to a shell prompt. Well, so far, so good. Now the rest of the debootstrap installation can be completed by the guest... mount -t devtmpfs none /dev mount -t proc none /proc mount -t sysfs none /sys /debootstrap/debootstrap --second-stage Unfortunately, this produced a badly corrupted root filesystem and the installation failed. Seems to be a bug in either Linux/mipsel or QEMU. (Has anyone tried a NetBSD installation?) I was able to avoid all that block IO entirely by using NFS. That way, the installation completed successfully... mount -o loop jessie-mipsel.img /export/jessie-mipsel echo "/export/jessie-mipsel 192.168.66.0/24(sync,rw,insecure,no_root_squash,no_subtree_check)" >> /etc/exports /etc/init.d/nfs start qemu-system-mips64el -M magnum -L . -drive if=scsi,unit=2,readonly=y,media=cdrom,format=raw,file=vmlinux.iso -drive if=scsi,unit=4,readonly=y,media=cdrom,format=raw,file=NetBSD-9.2-arc.iso -global ds1225y.filename=nvram -serial mon:stdio -serial null -net nic,model=dp83932,addr=00:00:00:aa:bb:cc -net bridge Actions: Start Windows NT -> Run a program Run setup scsi(0)cdrom(4)fdisk(0)boot scsi(0)cdrom(2)fdisk(0)vmlinux ip=dhcp nfsroot=192.168.66.1:/export/jessie-mipsel init=/bin/sh NetBSD/arc Bootstrap, Revision 1.1 (Wed May 12 13:15:55 UTC 2021) devopen: scsi(0)cdrom(2)fdisk(0) type disk file vmlinux 5706728+198952 [840960+1017335]=0x767d14 Linux version 5.10.47 (fthain@nippy) (mipsel-linux-gnu-gcc (btc) 6.4.0, GNU ld (btc) 2.28) #2 Fri Jul 9 16:28:12 AEST 2021 ARCH: Microsoft-Jazz PROMLIB: ARC firmware Version 1 Revision 2 CPU0 revision is: 00000400 (R4000PC) FPU revision is: 00000500 Primary instruction cache 8kB, VIPT, direct mapped, linesize 16 bytes. Primary data cache 8kB, direct mapped, VIPT, cache aliases, linesize 16 bytes Zone ranges: DMA [mem 0x0000000000000000-0x0000000000ffffff] Normal [mem 0x0000000001000000-0x0000000007ffffff] Movable zone start for each node Early memory node ranges node 0: [mem 0x0000000000000000-0x0000000007ffffff] Initmem setup node 0 [mem 0x0000000000000000-0x0000000007ffffff] Built 1 zonelists, mobility grouping on. Total pages: 32512 Kernel command line: console=ttyS0 root=/dev/nfs rw scsi(0)cdrom(2)fdisk(0)vmlinux ip=dhcp nfsroot=192.168.66.1:/export/jessie-mipsel init=/bin/sh Dentry cache hash table entries: 16384 (order: 4, 65536 bytes, linear) Inode-cache hash table entries: 8192 (order: 3, 32768 bytes, linear) mem auto-init: stack:off, heap alloc:off, heap free:off Memory: 123668K/131072K available (4249K kernel code, 234K rwdata, 928K rodata, 212K init, 135K bss, 7404K reserved, 0K cma-reserved) NR_IRQS: 256 random: get_random_bytes called from start_kernel+0x300/0x4b0 with crng_init=0 Console: colour dummy device 80x25 sched_clock: 32 bits at 100 Hz, resolution 10000000ns, wraps every 21474836475000000ns Calibrating delay loop... 1404.10 BogoMIPS (lpj=7020544) pid_max: default: 32768 minimum: 301 Mount-cache hash table entries: 1024 (order: 0, 4096 bytes, linear) Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes, linear) devtmpfs: initialized clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns futex hash table entries: 256 (order: -1, 3072 bytes, linear) NET: Registered protocol family 16 VDMA: R4030 DMA pagetables initialized. SCSI subsystem initialized NET: Registered protocol family 2 IP idents hash table entries: 2048 (order: 2, 16384 bytes, linear) tcp_listen_portaddr_hash hash table entries: 512 (order: 0, 4096 bytes, linear) TCP established hash table entries: 1024 (order: 0, 4096 bytes, linear) TCP bind hash table entries: 1024 (order: 0, 4096 bytes, linear) TCP: Hash tables configured (established 1024 bind 1024) UDP hash table entries: 256 (order: 0, 4096 bytes, linear) UDP-Lite hash table entries: 256 (order: 0, 4096 bytes, linear) NET: Registered protocol family 1 RPC: Registered named UNIX socket transport module. RPC: Registered udp transport module. RPC: Registered tcp transport module. RPC: Registered tcp NFSv4.1 backchannel transport module. workingset: timestamp_bits=30 max_order=15 bucket_order=0 Block layer SCSI generic (bsg) driver version 0.4 loaded (major 254) io scheduler mq-deadline registered io scheduler kyber registered Console: switching to colour frame buffer device 100x37 Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled printk: console [ttyS0] disabled serial8250.0: ttyS0 at MMIO 0xe0006000 (irq = 32, base_baud = 115200) is a 16550A printk: console [ttyS0] enabled serial8250.0: ttyS1 at MMIO 0xe0007000 (irq = 33, base_baud = 115200) is a 16550A jazz_esp jazz_esp.0: esp0: regs[(ptrval):0] irq[29] jazz_esp jazz_esp.0: esp0: is a FAS100A, 40 MHz (ccf=0), SCSI ID 7 random: fast init done scsi host0: esp PDC20230-C/20630 VLB ATA controller detected. scsi host1: pata_legacy ata1: PATA max PIO2 cmd 0x1f0 ctl 0x3f6 irq 14 scsi 0:0:2:0: CD-ROM QEMU QEMU CD-ROM 2.5+ PQ: 0 ANSI: 5 scsi target0:0:2: Beginning Domain Validation VDMA: Channel 0: Memory error! VDMA: Channel 0: Memory error! VDMA: Channel 0: Memory error! scsi target0:0:2: Domain Validation skipping write tests scsi target0:0:2: Ending Domain Validation VDMA: Channel 0: Memory error! scsi 0:0:4:0: CD-ROM QEMU QEMU CD-ROM 2.5+ PQ: 0 ANSI: 5 scsi target0:0:4: Beginning Domain Validation VDMA: Channel 0: Memory error! VDMA: Channel 0: Memory error! VDMA: Channel 0: Memory error! scsi target0:0:4: Domain Validation skipping write tests scsi target0:0:4: Ending Domain Validation VDMA: Channel 0: Memory error! scsi host1: pata_legacy ata2: PATA max PIO4 cmd 0x170 ctl 0x376 irq 15 scsi host1: pata_legacy ata3: PATA max PIO4 cmd 0x1e8 ctl 0x3ee irq 11 scsi host1: pata_legacy ata4: PATA max PIO4 cmd 0x168 ctl 0x36e irq 10 scsi host1: pata_legacy ata5: PATA max PIO4 cmd 0x1e0 ctl 0x3e6 irq 8 scsi host1: pata_legacy ata6: PATA max PIO4 cmd 0x160 ctl 0x366 irq 12 SONIC ethernet @e0001000, MAC 52:54:00:12:34:56, IRQ 28 serio: i8042 KBD port at 0xe0005000,0xe0005001 irq 30 serio: i8042 AUX port at 0xe0005000,0xe0005001 irq 31 input: AT Raw Set 2 keyboard as /devices/platform/i8042/serio0/input/input0 Sending DHCP requests ., OK IP-Config: Got DHCP answer from 192.168.66.1, my address is 192.168.66.112 IP-Config: Complete: device=eth0, hwaddr=52:54:00:12:34:56, ipaddr=192.168.66.112, mask=255.255.255.0, gw=192.168.66.1 host=192.168.66.112, domain=local, nis-domain=(none) bootserver=0.0.0.0, rootserver=192.168.66.1, rootpath= nameserver0=139.130.4.4 input: ImExPS/2 Generic Explorer Mouse as /devices/platform/i8042/serio1/input/input2 VFS: Mounted root (nfs filesystem) on device 0:12. Freeing prom memory: 376k freed Freeing prom memory: 60k freed Freeing prom memory: 4k freed Freeing unused kernel memory: 212K This architecture does not have kernel memory protection. Run /bin/sh as init process process '/bin/dash' started with executable stack /bin/sh: 0: can't access tty; job control turned off # mount -t devtmpfs none /dev # mount -t proc none /proc # mount -t sysfs none /sys # /debootstrap/debootstrap --second-stage ... # ping -c3 192.168.66.1 PING 192.168.66.1 (192.168.66.1) 56(84) bytes of data. 64 bytes from 192.168.66.1: icmp_seq=1 ttl=64 time=10.0 ms 64 bytes from 192.168.66.1: icmp_seq=2 ttl=64 time=0.000 ms 64 bytes from 192.168.66.1: icmp_seq=3 ttl=64 time=0.000 ms --- 192.168.66.1 ping statistics --- 3 packets transmitted, 3 received, 0% packet loss, time 2030ms rtt min/avg/max/mdev = 0.000/3.333/10.000/4.714 ms # After the debootstrap command completes, the last steps are manual configuration, as per the usual debootstrap procedure: https://wiki.debian.org/Debootstrap https://gist.github.com/varqox/42e213b6b2dde2b636ef Note that this only _barely_ works. A slightly larger vmlinux breaks the bootloader, and a slightly longer boot command breaks ARC.
