Patch "MIPS: SMP-CPS: fix build error when HOTPLUG_CPU not set" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    MIPS: SMP-CPS: fix build error when HOTPLUG_CPU not set

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mips-smp-cps-fix-build-error-when-hotplug_cpu-not-se.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit bda2e1356a5316b0d97a1fdf35df09d2cf0ad7ae
Author: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Date:   Fri Feb 17 12:07:49 2023 -0800

    MIPS: SMP-CPS: fix build error when HOTPLUG_CPU not set
    
    [ Upstream commit 6f02e39fa40f16c24e7a5c599a854c0d1682788d ]
    
    When MIPS_CPS=y, MIPS_CPS_PM is not set, HOTPLUG_CPU is not set, and
    KEXEC=y, cps_shutdown_this_cpu() attempts to call cps_pm_enter_state(),
    which is not built when MIPS_CPS_PM is not set.
    Conditionally execute the else branch based on CONFIG_HOTPLUG_CPU
    to remove the build error.
    This build failure is from a randconfig file.
    
    mips-linux-ld: arch/mips/kernel/smp-cps.o: in function `$L162':
    smp-cps.c:(.text.cps_kexec_nonboot_cpu+0x31c): undefined reference to `cps_pm_enter_state'
    
    Fixes: 1447864bee4c ("MIPS: kexec: CPS systems to halt nonboot CPUs")
    Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
    Cc: Dengcheng Zhu <dzhu@xxxxxxxxxxxx>
    Cc: Paul Burton <paulburton@xxxxxxxxxx>
    Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
    Cc: linux-mips@xxxxxxxxxxxxxxx
    Cc: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxx>
    Signed-off-by: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/arch/mips/kernel/smp-cps.c b/arch/mips/kernel/smp-cps.c
index dbb3f1fc71ab6..f659adb681bc3 100644
--- a/arch/mips/kernel/smp-cps.c
+++ b/arch/mips/kernel/smp-cps.c
@@ -423,9 +423,11 @@ static void cps_shutdown_this_cpu(enum cpu_death death)
 			wmb();
 		}
 	} else {
-		pr_debug("Gating power to core %d\n", core);
-		/* Power down the core */
-		cps_pm_enter_state(CPS_PM_POWER_GATED);
+		if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
+			pr_debug("Gating power to core %d\n", core);
+			/* Power down the core */
+			cps_pm_enter_state(CPS_PM_POWER_GATED);
+		}
 	}
 }