openwrt/target/linux/armvirt
Aleksander Jan Bajkowski 9226f1e419
kernel: disable CONFIG_CPU_LITTLE_ENDIAN in generic config
Endianness depends on CPU architecture. CONFIG_CPU_(BIG/LITTLE)_ENDIAN should
be enabled on target or subtarget based on SoC architecture.

Fixes warning:
$ make kernel_oldconfig CONFIG_TARGET=subtarget
...
.config:1008:warning: override: CPU_LITTLE_ENDIAN changes choice state
....

Summary:
- ARC - only the CONFIG_CPU_BIG_ENDIAN symbol is defined for this architeture.
  If it is disabled then the processor operates in LITTLE_ENDIAN mode (default),
- ARM32 - CONFIG_CPU_LITTLE_ENDIAN symbol available since kernel 5.19. This
  option should be enabled after OpenWRT moves to kernel 6.x. After refreshing
  the kernel, the symbol disappears,
- ARM64 - enabled CONFIG_CPU_LITTLE_ENDIAN,
- MIPS - enabled relevant symbols,
- POWERPC -  enabled CONFIG_CPU_BIG_ENDIAN,
- UML - Symbols are not defined for this architecture,
- X86 - always little endian. Symbols are not defined for this architecture.

Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
2022-10-21 13:47:01 +02:00
..
32
64 kernel: disable CONFIG_CPU_LITTLE_ENDIAN in generic config 2022-10-21 13:47:01 +02:00
base-files/etc
image
Makefile armvirt: make 5.15 kernel default 2022-09-14 16:45:06 +02:00
README
config-5.10
config-5.15

README

This is intended to be used with OpenWrt project to provide image for use with
QEMU ARM virt machine.

Run with qemu-system-arm

	# boot with initramfs embedded in
	qemu-system-arm -nographic -M virt -m 64 -kernel openwrt-armvirt-32-zImage-initramfs

	# boot with accel=kvm
	qemu-system-arm -nographic -M virt,accel=kvm -cpu host -m 64 -kernel
	openwrt-armvirt-32-zImage-initramfs

	# boot with a separate rootfs
	qemu-system-arm -nographic -M virt -m 64 -kernel openwrt-armvirt-32-zImage \
	  -drive file=openwrt-armvirt-32-root.ext4,format=raw,if=virtio -append 'root=/dev/vda rootwait'

	# boot with local dir as rootfs
	qemu-system-arm -nographic -M virt -m 64 -kernel openwrt-armvirt-32-zImage \
	  -fsdev local,id=rootdev,path=root-armvirt/,security_model=none \
	  -device virtio-9p-pci,fsdev=rootdev,mount_tag=/dev/root \
	  -append 'rootflags=trans=virtio,version=9p2000.L,cache=loose rootfstype=9p'

Run with kvmtool

	# start a named machine
	lkvm run -k openwrt-armvirt-32-zImage -i openwrt-armvirt-32-rootfs.cpio --name armvirt0

	# start with virtio-9p rootfs
	lkvm run -k openwrt-armvirt-32-zImage -d root-armvirt/

	# stop "armvirt0"
	lkvm stop --name armvirt0

	# stop all
	lkvm stop --all

The multi-platform ARMv8 target can be used with QEMU:

	qemu-system-aarch64 -machine virt -cpu cortex-a57 -nographic \
		-kernel openwrt-armvirt-64-Image-initramfs \