Re: [Xen-devel] [PATCH v3 11/13] xen: arm: enable synchronous console while starting secondary CPUs

[Julien Grall <julien.grall@xxxxxxxxxx>]

On 11/25/2013 11:07 AM, Ian Campbell wrote:
> 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@xxxxxxxxxx>
Acked-by: Julien Grall <julien.grall@xxxxxxxxxx>
> Cc: Keir Fraser <keir@xxxxxxx>
> ---
> 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 7636ab8..e862477 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);
--
Julien Grall

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