General Information

This is ski: an ia64 instruction set simulator

This repository is a fork of: http://ski.sourceforge.net

The license is GPL-2.

Installation

See the file 'INSTALL'

Running

Running Ski requires a few moving parts:

build ski-specific linux kernel
prepare disk image of a file system
run ski
Building kernel

The caveat is that upstream removed Ski-specific bits from linux-5.0. Thus latest supported kernel by Ski is 4.19 (see TODOs to get Ski ported to newer kernels).

Once you get ia64-unknown-linux cross-compiler toolchain it is straightforward:

$ wget https://cdn.kernel.org/pub/linux/kernel/v4.x/linux-4.19.241.tar.xz
$ tar -xf linux-4.19.241.tar.xz
$ cd linux-4.19.241
$ ARCH=ia64 CROSS_COMPILE=ia64-unknown-linux-gnu- make sim_defconfig
$ ARCH=ia64 CROSS_COMPILE=ia64-unknown-linux-gnu- make -j$(nproc)

The toolchain versions I used to get working setup are:

gcc-11.3.0
binutils-2.36

Newer ones should work as well.

Preparing disk image

That can be any filesystem supported by guest kernel. sim_defconfig supports ext2 as is. I used fresh Gentoo image to verify it:

$ wget https://bouncer.gentoo.org/fetch/root/all/releases/ia64/autobuilds/20220420T025349Z/stage3-ia64-systemd-20220420T025349Z.tar.xz
$ dd of=sdc if=/dev/zero bs=512 count=10485760 #5G
$ /sbin/mke2fs sdc
$ mkdir mnt
$ mknod /dev/loop0 b 7 0
$ mount -t ext2 -oloop sdc ./mnt
$ cd mnt
$ tar -xpf ../stage3-ia64-systemd-20220420T025349Z.tar.xz
# ignore dev creation failures
$ cd ..
$ umount mnt

Here we created sdc file and populated it with contents of stage3.

Running Ski

Once you have got the bits it should just run:

$ bski linux-4.19.241/arch/ia64/hp/sim/boot/bootloader linux-4.19.241/vmlinux root=/dev/sda simscsi=./sd simeth=eth0 init=/bin/bash PATH=/bin rw
...
loading linux-4.19.241/vmlinux...
starting kernel...
Linux version 4.19.241 (root@gentoo) (gcc version 11.3.0 (Gentoo 11.3.0 p4)) #1 SMP PREEMPT Tue May 3 23:52:46 BST 2022
...
root@(none) / # mount -t proc proc /proc
root@(none) / # uname -a
Linux (none) 4.19.241 #1 SMP PREEMPT Tue May 3 23:52:46 BST 2022 ia64 McKinley HP Ski Simulator GNU/Linux
root@(none) / # cat /proc/cpuinfo
processor  : 0
vendor     : HP Ski Simulator
arch       : IA-64
family     : 31
model      : 0
model name : McKinley
revision   : 0
archrev    : 0
features   : branchlong, 16-byte atomic ops
cpu number : 0
cpu regs   : 4
cpu MHz    : 2.000
itc MHz    : 2.000000
BogoMIPS   : 1.23
siblings   : 1

Fork-specific notes

The goal of this fork is to keep ski running on modern systems. This include but is not limited to:

pulling in downstream distribution patches
updating dynamic translator code to work on
modern linux

New additions:

Experimental minimal UART8250 console output. Can be used with the
following setup:
- kernel .config:
  CONFIG_SERIAL_EARLYCON=y
  CONFIG_SERIAL_8250=y
  CONFIG_SERIAL_8250_CONSOLE=y
- kernel parameters:
  earlycon=uart8250,mmio,0xff5e0000
  TODOs:
- port bootloader over to earlycon to get visible output for
  CONFIG_HP_SIMSERIAL_CONSOLE=n kernels.
- export UART1/UART2 via some interface (hcdp? SPCR?) to make it
  usable as a promary console after early boot as well.

General software support for ia64

Last versions supported by the toolchain:

glibc-2.38, removed in https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=460860f457e2a889785c506e8c77d4a7dff24d3e
linux-6.6, removed in https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=cf8e8658100d4eae80ce9b21f7a81cb024dd5057
gcc-13, still not removed as of 2024-01-08
binutils-2.41, still not removed as of 2024-01-08

TODOs

Port from ski-specific virtual devices to more standard VIRTIO:
- simcons -> virtio-console
- simscsi -> virtio-blk
- simeth -> virtio-net
Bring CPU emulator up to the state where we could include it in qemu
- Currently CPU emulator uses global state for various things. It's
  not very reusable as is.
stop requiring 'bootloader' and be able to run unmodified ia64 kernel
- plumb EFI mapping
- plumb ACPI space
- plumb PCI space
- add support for initramfs loading
covert doc/ documentation into something closer to plain text