Upgrade to 4.4.50-rt62

[kvmfornfv.git] / kernel / arch / arm64 / kernel / cpufeature.c

diff --git a/kernel/arch/arm64/kernel/cpufeature.c b/kernel/arch/arm64/kernel/cpufeature.c
index 0669c63..2735bf8 100644 (file)
--- a/kernel/arch/arm64/kernel/cpufeature.c
+++ b/kernel/arch/arm64/kernel/cpufeature.c
@@ -19,7 +19,9 @@
 #define pr_fmt(fmt) "CPU features: " fmt
 
 #include <linux/bsearch.h>
+#include <linux/cpumask.h>
 #include <linux/sort.h>
+#include <linux/stop_machine.h>
 #include <linux/types.h>
 #include <asm/cpu.h>
 #include <asm/cpufeature.h>
@@ -764,7 +766,13 @@ static void enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps)
 
        for (i = 0; caps[i].desc; i++)
                if (caps[i].enable && cpus_have_cap(caps[i].capability))
-                       on_each_cpu(caps[i].enable, NULL, true);
+                       /*
+                        * Use stop_machine() as it schedules the work allowing
+                        * us to modify PSTATE, instead of on_each_cpu() which
+                        * uses an IPI, giving us a PSTATE that disappears when
+                        * we return.
+                        */
+                       stop_machine(caps[i].enable, NULL, cpu_online_mask);
 }
 
 #ifdef CONFIG_HOTPLUG_CPU