diff mbox series

[RFC,v2,23/35] ACPI: Warn when the present bit changes but the feature is not enabled

Message ID 20230913163823.7880-24-james.morse@arm.com (mailing list archive)
State Handled Elsewhere, archived
Headers show
Series ACPI/arm64: add support for virtual cpuhotplug | expand

Commit Message

James Morse Sept. 13, 2023, 4:38 p.m. UTC
ACPI firmware can trigger the events to add and remove CPUs, but the
OS may not support this.

Print a warning when this happens.

This gives early warning on arm64 systems that don't support
CONFIG_ACPI_HOTPLUG_PRESENT_CPU, as making CPUs not present has
side effects for other parts of the system.

Signed-off-by: James Morse <james.morse@arm.com>
---
 drivers/acpi/acpi_processor.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

Comments

Jonathan Cameron Sept. 14, 2023, 2:32 p.m. UTC | #1
On Wed, 13 Sep 2023 16:38:11 +0000
James Morse <james.morse@arm.com> wrote:

> ACPI firmware can trigger the events to add and remove CPUs, but the
> OS may not support this.
> 
> Print a warning when this happens.
> 
> This gives early warning on arm64 systems that don't support
> CONFIG_ACPI_HOTPLUG_PRESENT_CPU, as making CPUs not present has
> side effects for other parts of the system.
> 
> Signed-off-by: James Morse <james.morse@arm.com>
Seem like a good idea to me.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> ---
>  drivers/acpi/acpi_processor.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
> index 2cafea1edc24..b67616079751 100644
> --- a/drivers/acpi/acpi_processor.c
> +++ b/drivers/acpi/acpi_processor.c
> @@ -188,8 +188,10 @@ static int acpi_processor_make_present(struct acpi_processor *pr)
>  	acpi_status status;
>  	int ret;
>  
> -	if (!IS_ENABLED(CONFIG_ACPI_HOTPLUG_PRESENT_CPU))
> +	if (!IS_ENABLED(CONFIG_ACPI_HOTPLUG_PRESENT_CPU)) {
> +		pr_err_once("Changing CPU present bit is not supported\n");
>  		return -ENODEV;
> +	}
>  
>  	if (invalid_phys_cpuid(pr->phys_id))
>  		return -ENODEV;
> @@ -462,8 +464,10 @@ static void acpi_processor_make_not_present(struct acpi_device *device)
>  {
>  	struct acpi_processor *pr;
>  
> -	if (!IS_ENABLED(CONFIG_ACPI_HOTPLUG_PRESENT_CPU))
> +	if (!IS_ENABLED(CONFIG_ACPI_HOTPLUG_PRESENT_CPU)) {
> +		pr_err_once("Changing CPU present bit is not supported");
>  		return;
> +	}
>  
>  	pr = acpi_driver_data(device);
>  	if (pr->id >= nr_cpu_ids)
Gavin Shan Sept. 19, 2023, 12:49 a.m. UTC | #2
On 9/14/23 02:38, James Morse wrote:
> ACPI firmware can trigger the events to add and remove CPUs, but the
> OS may not support this.
> 
> Print a warning when this happens.
           ^^^^^^^
           error message
> 
> This gives early warning on arm64 systems that don't support
> CONFIG_ACPI_HOTPLUG_PRESENT_CPU, as making CPUs not present has
> side effects for other parts of the system.
> 
> Signed-off-by: James Morse <james.morse@arm.com>
> ---
>   drivers/acpi/acpi_processor.c | 8 ++++++--
>   1 file changed, 6 insertions(+), 2 deletions(-)
> 

Maybe a warning message is enough, but a error message
is also fine, I think.

Reviewed-by: Gavin Shan <gshan@redhat.com>

> diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
> index 2cafea1edc24..b67616079751 100644
> --- a/drivers/acpi/acpi_processor.c
> +++ b/drivers/acpi/acpi_processor.c
> @@ -188,8 +188,10 @@ static int acpi_processor_make_present(struct acpi_processor *pr)
>   	acpi_status status;
>   	int ret;
>   
> -	if (!IS_ENABLED(CONFIG_ACPI_HOTPLUG_PRESENT_CPU))
> +	if (!IS_ENABLED(CONFIG_ACPI_HOTPLUG_PRESENT_CPU)) {
> +		pr_err_once("Changing CPU present bit is not supported\n");
>   		return -ENODEV;
> +	}
>   
>   	if (invalid_phys_cpuid(pr->phys_id))
>   		return -ENODEV;
> @@ -462,8 +464,10 @@ static void acpi_processor_make_not_present(struct acpi_device *device)
>   {
>   	struct acpi_processor *pr;
>   
> -	if (!IS_ENABLED(CONFIG_ACPI_HOTPLUG_PRESENT_CPU))
> +	if (!IS_ENABLED(CONFIG_ACPI_HOTPLUG_PRESENT_CPU)) {
> +		pr_err_once("Changing CPU present bit is not supported");
>   		return;
> +	}
>   
>   	pr = acpi_driver_data(device);
>   	if (pr->id >= nr_cpu_ids)

Thanks,
Gavin
diff mbox series

Patch

diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index 2cafea1edc24..b67616079751 100644
--- a/drivers/acpi/acpi_processor.c
+++ b/drivers/acpi/acpi_processor.c
@@ -188,8 +188,10 @@  static int acpi_processor_make_present(struct acpi_processor *pr)
 	acpi_status status;
 	int ret;
 
-	if (!IS_ENABLED(CONFIG_ACPI_HOTPLUG_PRESENT_CPU))
+	if (!IS_ENABLED(CONFIG_ACPI_HOTPLUG_PRESENT_CPU)) {
+		pr_err_once("Changing CPU present bit is not supported\n");
 		return -ENODEV;
+	}
 
 	if (invalid_phys_cpuid(pr->phys_id))
 		return -ENODEV;
@@ -462,8 +464,10 @@  static void acpi_processor_make_not_present(struct acpi_device *device)
 {
 	struct acpi_processor *pr;
 
-	if (!IS_ENABLED(CONFIG_ACPI_HOTPLUG_PRESENT_CPU))
+	if (!IS_ENABLED(CONFIG_ACPI_HOTPLUG_PRESENT_CPU)) {
+		pr_err_once("Changing CPU present bit is not supported");
 		return;
+	}
 
 	pr = acpi_driver_data(device);
 	if (pr->id >= nr_cpu_ids)