From: Jayachandran C <jnair@caviumnetworks.com>
Date: Mon, 17 Jun 2019 20:35:18 +0000 (+0300)
Subject: arm64: Improve parking of stopped CPUs
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=dccc9da22dedad203acea355b0e4d946b71172e5;p=linux.git

arm64: Improve parking of stopped CPUs

The current code puts the stopped cpus in an 'yield' instruction loop.
Using a busy loop here is unnecessary, we can use the cpu_park_loop()
function here to do a wfi/wfe.

Signed-off-by: Jayachandran C <jnair@caviumnetworks.com>
Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---

diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 83cdb0aa2ff17..932461da5dd73 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -850,9 +850,7 @@ static void ipi_cpu_stop(unsigned int cpu)
 
 	local_daif_mask();
 	sdei_mask_local_cpu();
-
-	while (1)
-		cpu_relax();
+	cpu_park_loop();
 }
 
 #ifdef CONFIG_KEXEC_CORE