id = 1693
title = "qemu-system-nios2 not working on s390x (big endian) hosts"
state = "closed"
created_at = "2023-06-07T08:33:31.965Z"
closed_at = "2023-07-01T10:12:35.751Z"
labels = ["host: s390", "kind::Bug", "target: nios2", "workflow::Patch available"]
url = "https://gitlab.com/qemu-project/qemu/-/issues/1693"
host-os = "Linux / RHEL 9"
host-arch = "s390x"
qemu-version = "current master branch (commit 7ce5a15fa633c7683d4)"
guest-os = "Linux"
guest-arch = "nios2"
description = """qemu-system-nios2 fails to boot a Linux kernel on s390x hosts."""
reproduce = """1. wget https://qemu-advcal.gitlab.io/qac-best-of-multiarch/download/day14.tar.xz
2. tar -xJf day14.tar.xz 
3. cd day14/
4. qemu-system-nios2 -nographic -kernel vmlinux.elf"""
additional = """When running with "-d in_asm", it seems like the code initially starts executing ok, but in one of the early translation blocks, there is a difference when comparing the log with a run from a x86 host:

```
IN: fdt_check_header
0xc81afd48:  ldw\tr3,0(r4)
0xc81afd4c:  srli\tr5,r3,24
0xc81afd50:  slli\tr2,r3,24
0xc81afd54:  or\tr2,r2,r5
0xc81afd58:  slli\tr5,r3,8
0xc81afd5c:  srli\tr3,r3,8
0xc81afd60:  andhi\tr5,r5,255
0xc81afd64:  andi\tr3,r3,65280
0xc81afd68:  or\tr2,r2,r5
0xc81afd6c:  or\tr2,r2,r3
0xc81afd70:  movhi\tr3,53262
0xc81afd74:  addi\tr3,r3,-275
0xc81afd78:  bne\tr2,r3,0xc81afde8
```

On the x86 host, the branch at the end is not taken, while on the s390x host, the branch is taken."""