[PATCH v2 12/15] xen: arm: enable synchronous console while starting secondary CPUs

[Ian Campbell <ian.campbell@citrix.com>]

Setting synchronous console ensures that any printk hits the buffer
immediately and that any outstanding queued log messages are flushed. This
ensures that such log messages are not being printed while the secondary CPU
may be using early_printk during early bringup.

Signed-of-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Keir Fraser <keir@xen.org>
---
v2: improved commit message.
---
 xen/arch/arm/smpboot.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
index b6a1307..f6cd9d7 100644
--- a/xen/arch/arm/smpboot.c
+++ b/xen/arch/arm/smpboot.c
@@ -28,6 +28,7 @@
 #include <xen/softirq.h>
 #include <xen/timer.h>
 #include <xen/irq.h>
+#include <xen/console.h>
 #include <asm/gic.h>
 
 cpumask_t cpu_online_map;
@@ -356,6 +357,8 @@ int __cpu_up(unsigned int cpu)
     if ( rc < 0 )
         return rc;
 
+    console_start_sync(); /* Secondary may use early_printk */
+
     /* Tell the remote CPU which stack to boot on. */
     init_data.stack = idle_vcpu[cpu]->arch.stack;
 
@@ -368,6 +371,8 @@ int __cpu_up(unsigned int cpu)
 
     rc = arch_cpu_up(cpu);
 
+    console_end_sync();
+
     if ( rc < 0 )
     {
         printk("Failed to bring up CPU%d\n", cpu);
-- 
1.7.10.4