Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64...

[karo-tx-linux.git] / arch / arm64 / kernel / smp.c

diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 049aa8d5c5533ad222357db4b54b3e21d394f079..40f38f46c8e0ad6ca8fb375fb35554ebd7a1a0f1 100644 (file)
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -230,6 +230,19 @@ int __cpu_disable(void)
        return 0;
 }
 
+static int op_cpu_kill(unsigned int cpu)
+{
+       /*
+        * If we have no means of synchronising with the dying CPU, then assume
+        * that it is really dead. We can only wait for an arbitrary length of
+        * time and hope that it's dead, so let's skip the wait and just hope.
+        */
+       if (!cpu_ops[cpu]->cpu_kill)
+               return 1;
+
+       return cpu_ops[cpu]->cpu_kill(cpu);
+}
+
 static DECLARE_COMPLETION(cpu_died);
 
 /*
@@ -243,6 +256,15 @@ void __cpu_die(unsigned int cpu)
                return;
        }
        pr_notice("CPU%u: shutdown\n", cpu);
+
+       /*
+        * Now that the dying CPU is beyond the point of no return w.r.t.
+        * in-kernel synchronisation, try to get the firwmare to help us to
+        * verify that it has really left the kernel before we consider
+        * clobbering anything it might still be using.
+        */
+       if (!op_cpu_kill(cpu))
+               pr_warn("CPU%d may not have shut down cleanly\n", cpu);
 }
 
 /*