[PATCH v6 0/1] MIPS: Fix idle VS timer enqueue

From: Marco Crivellari
Date: Sat Mar 15 2025 - 15:40:25 EST


This patch aims to fix idle routine while the CPU receive an interrupt,
because __r4k_wait() only checks if TIF_NEED_RESCHED is set before
going to sleep.
The same behavior has been changed in LoongArch [1].

Code (cross) compiled successfully and I manage to test it on a VM
emulating a malta board. I ran QEMU with:

qemu-system-mips64el -M malta -m 2G -kernel vmlinux -serial stdio -drive \
file=rootfs.ext2,format=raw -append "rootwait root=/dev/sda" -cpu 5Kc

rootfs generated using buildroot (malta default configuration).

- [1] https://github.com/chenhuacai/linux/commit/a8aa673ea46c03b3f62992ffa4ffe810ac84f6e3

---
Changes in v6:
- typo in comment, capitalise sentences and full stops

Changes in v5:
- comment: idle interrupt region, instead of rollback region

Changes in v4:
- comments: 36 byte region

Changes in v3:
- changed "daddiu k0, 1" with PTR_ADDIU k0, 5
- replaced CONFIG_CPU_MICROMIPS with 3 _ssnop followed by _ehb
- integrated the commit message with explanation about
CONFIG_CPU_MICROMIPS replacement

Changes in v2:
- Changes introduced by Huacai:
https://lore.kernel.org/linux-mips/20250214105047.150835-1-marco.crivellari@xxxxxxxx/T/#m75d9c587829e15e0d7baec13078be4e65c936408

Marco Crivellari (1):
MIPS: Fix idle VS timer enqueue

arch/mips/kernel/genex.S | 42 ++++++++++++++++++++++------------------
arch/mips/kernel/idle.c | 1 -
2 files changed, 23 insertions(+), 20 deletions(-)

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2.48.1