x86, kexec: Make sure to stop all CPUs before exiting the kernel

x86 smp_ops now has a new op, stop_other_cpus which takes a parameter
"wait" this allows the caller to specify if it wants to stop until all
the cpus have processed the stop IPI.  This is required specifically
for the kexec case where we should wait for all the cpus to be stopped
before starting the new kernel.  We now wait for the cpus to stop in
all cases except for panic/kdump where we expect things to be broken
and we are doing our best to make things work anyway.

This patch fixes a legitimate regression, which was introduced during
2.6.30, by commit id 4ef702c10b5df18ab04921fc252c26421d4d6c75.

Signed-off-by: Alok N Kataria <akataria@vmware.com>
LKML-Reference: <1286833028.1372.20.camel@ank32.eng.vmware.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: <stable@kernel.org> v2.6.30-36
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

2 files changed, 4 insertions, 4 deletions

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 7d46c844141..44f80861382 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1018,7 +1018,7 @@ static void xen_reboot(int reason)
         struct sched_shutdown r = { .reason = reason };
 
 #ifdef CONFIG_SMP
-        smp_send_stop();
+        stop_other_cpus();
 #endif
 
         if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r))
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 25f232b18a8..f4d01003146 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -400,9 +400,9 @@ static void stop_self(void *v)
         BUG();
 }
 
-static void xen_smp_send_stop(void)
+static void xen_stop_other_cpus(int wait)
 {
-        smp_call_function(stop_self, NULL, 0);
+        smp_call_function(stop_self, NULL, wait);
 }
 
 static void xen_smp_send_reschedule(int cpu)
@@ -470,7 +470,7 @@ static const struct smp_ops xen_smp_ops __initdata = {
         .cpu_disable = xen_cpu_disable,
         .play_dead = xen_play_dead,
 
-        .smp_send_stop = xen_smp_send_stop,
+        .stop_other_cpus = xen_stop_other_cpus,
         .smp_send_reschedule = xen_smp_send_reschedule,
 
         .send_call_func_ipi = xen_smp_send_call_function_ipi,