openwrt/target/linux/generic/backport-6.6/0081-v6.10-cpu-Fix-broken-cmdline-nosmp-and-maxcpus-0.patch
Martin Schiller 48d0068bb1 generic: 6.6: backport fix for broken cmdline "nosmp" and "maxcpus=0"
This backports the fix for the broken "nosmp" and "maxcpus=0" cmdline
params.

Signed-off-by: Martin Schiller <ms@dev.tdt.de>
Link: https://github.com/openwrt/openwrt/pull/15811
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
2024-07-06 17:50:23 +02:00

39 lines
1.4 KiB
Diff

From 6ef8eb5125722c241fd60d7b0c872d5c2e5dd4ca Mon Sep 17 00:00:00 2001
From: Huacai Chen <chenhuacai@loongson.cn>
Date: Tue, 18 Jun 2024 16:13:36 +0800
Subject: [PATCH] cpu: Fix broken cmdline "nosmp" and "maxcpus=0"
After the rework of "Parallel CPU bringup", the cmdline "nosmp" and
"maxcpus=0" parameters are not working anymore. These parameters set
setup_max_cpus to zero and that's handed to bringup_nonboot_cpus().
The code there does a decrement before checking for zero, which brings it
into the negative space and brings up all CPUs.
Add a zero check at the beginning of the function to prevent this.
[ tglx: Massaged change log ]
Fixes: 18415f33e2ac4ab382 ("cpu/hotplug: Allow "parallel" bringup up to CPUHP_BP_KICK_AP_STATE")
Fixes: 06c6796e0304234da6 ("cpu/hotplug: Fix off by one in cpuhp_bringup_mask()")
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240618081336.3996825-1-chenhuacai@loongson.cn
---
kernel/cpu.c | 3 +++
1 file changed, 3 insertions(+)
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1907,6 +1907,9 @@ static inline bool cpuhp_bringup_cpus_pa
void __init bringup_nonboot_cpus(unsigned int max_cpus)
{
+ if (!max_cpus)
+ return;
+
/* Try parallel bringup optimization if enabled */
if (cpuhp_bringup_cpus_parallel(max_cpus))
return;