[PATCH] xen/cpu: Fix ARM build following c/s 597fbb8

[PATCH] xen/cpu: Fix ARM build following c/s 597fbb8

[Andrew Cooper]

c/s 597fbb8 "xen/timers: Fix memory leak with cpu unplug/plug" broke the ARM
build by being the first patch to add park_offline_cpus to common code.

While it is currently specific to Intel hardware (for reasons of being able to
handle machine check exceptions without an immediate system reset), it isn't
inherently architecture specific, so define it to be false on ARM for now.

Add a comment in both smp.h headers explaining the intended behaviour of the
option.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Julien Grall <julien.grall@arm.com>

This time build tested on ARM.  Sorry!
---
 xen/include/asm-arm/smp.h | 6 ++++++
 xen/include/asm-x86/smp.h | 4 ++++
 2 files changed, 10 insertions(+)

diff --git a/xen/include/asm-arm/smp.h b/xen/include/asm-arm/smp.h
index 3c12268..fdbcefa 100644
--- a/xen/include/asm-arm/smp.h
+++ b/xen/include/asm-arm/smp.h
@@ -14,6 +14,12 @@ DECLARE_PER_CPU(cpumask_var_t, cpu_core_mask);
 
 #define raw_smp_processor_id() (get_processor_id())
 
+/*
+ * Do we, for platform reasons, need to actually keep CPUs online when we
+ * would otherwise prefer them to be off?
+ */
+#define park_offline_cpus false
+
 extern void noreturn stop_cpu(void);
 
 extern int arch_smp_init(void);
diff --git a/xen/include/asm-x86/smp.h b/xen/include/asm-x86/smp.h
index 09c5545..9f533f9 100644
--- a/xen/include/asm-x86/smp.h
+++ b/xen/include/asm-x86/smp.h
@@ -26,6 +26,10 @@ DECLARE_PER_CPU(cpumask_var_t, cpu_sibling_mask);
 DECLARE_PER_CPU(cpumask_var_t, cpu_core_mask);
 DECLARE_PER_CPU(cpumask_var_t, scratch_cpumask);
 
+/*
+ * Do we, for platform reasons, need to actually keep CPUs online when we
+ * would otherwise prefer them to be off?
+ */
 extern bool park_offline_cpus;
 
 void smp_send_nmi_allbutself(void);
-- 
2.1.4


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Re: [PATCH] xen/cpu: Fix ARM build following c/s 597fbb8

[Julien Grall]

Hi Andrew,

On 08/04/2019 18:20, Andrew Cooper wrote:
> c/s 597fbb8 "xen/timers: Fix memory leak with cpu unplug/plug" broke the ARM
> build by being the first patch to add park_offline_cpus to common code.
> 
> While it is currently specific to Intel hardware (for reasons of being able to
> handle machine check exceptions without an immediate system reset), it isn't
> inherently architecture specific, so define it to be false on ARM for now.
> 
> Add a comment in both smp.h headers explaining the intended behaviour of the
> option.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

Reviewed-by: Julien Grall <julien.grall@arm.com>

Cheers,

> ---
> CC: Jan Beulich <JBeulich@suse.com>
> CC: Wei Liu <wei.liu2@citrix.com>
> CC: Roger Pau Monné <roger.pau@citrix.com>
> CC: Stefano Stabellini <sstabellini@kernel.org>
> CC: Julien Grall <julien.grall@arm.com>
> 
> This time build tested on ARM.  Sorry!
> ---
>   xen/include/asm-arm/smp.h | 6 ++++++
>   xen/include/asm-x86/smp.h | 4 ++++
>   2 files changed, 10 insertions(+)
> 
> diff --git a/xen/include/asm-arm/smp.h b/xen/include/asm-arm/smp.h
> index 3c12268..fdbcefa 100644
> --- a/xen/include/asm-arm/smp.h
> +++ b/xen/include/asm-arm/smp.h
> @@ -14,6 +14,12 @@ DECLARE_PER_CPU(cpumask_var_t, cpu_core_mask);
>   
>   #define raw_smp_processor_id() (get_processor_id())
>   
> +/*
> + * Do we, for platform reasons, need to actually keep CPUs online when we
> + * would otherwise prefer them to be off?
> + */
> +#define park_offline_cpus false
> +
>   extern void noreturn stop_cpu(void);
>   
>   extern int arch_smp_init(void);
> diff --git a/xen/include/asm-x86/smp.h b/xen/include/asm-x86/smp.h
> index 09c5545..9f533f9 100644
> --- a/xen/include/asm-x86/smp.h
> +++ b/xen/include/asm-x86/smp.h
> @@ -26,6 +26,10 @@ DECLARE_PER_CPU(cpumask_var_t, cpu_sibling_mask);
>   DECLARE_PER_CPU(cpumask_var_t, cpu_core_mask);
>   DECLARE_PER_CPU(cpumask_var_t, scratch_cpumask);
>   
> +/*
> + * Do we, for platform reasons, need to actually keep CPUs online when we
> + * would otherwise prefer them to be off?
> + */
>   extern bool park_offline_cpus;
>   
>   void smp_send_nmi_allbutself(void);
> 

-- 
Julien Grall

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Re: [PATCH] xen/cpu: Fix ARM build following c/s 597fbb8

[Wei Liu]

On Mon, Apr 08, 2019 at 06:20:07PM +0100, Andrew Cooper wrote:
> c/s 597fbb8 "xen/timers: Fix memory leak with cpu unplug/plug" broke the ARM
> build by being the first patch to add park_offline_cpus to common code.
> 
> While it is currently specific to Intel hardware (for reasons of being able to
> handle machine check exceptions without an immediate system reset), it isn't
> inherently architecture specific, so define it to be false on ARM for now.
> 
> Add a comment in both smp.h headers explaining the intended behaviour of the
> option.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

Reviewed-by: Wei Liu <wei.liu2@citrix.com>

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