diff mbox series

[1/2] ACPI/PPTT: Add support for ACPI 6.3 thread flag

Message ID 20190523224015.56270-2-jeremy.linton@arm.com
State Superseded
Headers show
Series arm64/PPTT ACPI 6.3 thread flag support | expand

Commit Message

Jeremy Linton May 23, 2019, 10:40 p.m. UTC 
ACPI 6.3 adds a flag to the CPU node to indicate whether
the given PE is a thread. Add a function to return that
information for a given linux logical CPU.

Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>

---
 drivers/acpi/pptt.c  | 53 +++++++++++++++++++++++++++++++++++++++++++-
 include/linux/acpi.h |  5 +++++
 2 files changed, 57 insertions(+), 1 deletion(-)

-- 
2.21.0

Comments

Sudeep Holla June 7, 2019, 10:03 a.m. UTC | #1 
On Thu, May 23, 2019 at 05:40:14PM -0500, Jeremy Linton wrote:
> ACPI 6.3 adds a flag to the CPU node to indicate whether

> the given PE is a thread. Add a function to return that

> information for a given linux logical CPU.

> 

> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>

> ---

>  drivers/acpi/pptt.c  | 53 +++++++++++++++++++++++++++++++++++++++++++-

>  include/linux/acpi.h |  5 +++++

>  2 files changed, 57 insertions(+), 1 deletion(-)

> 

> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c

> index b72e6afaa8fb..6f43a0c05f61 100644

> --- a/drivers/acpi/pptt.c

> +++ b/drivers/acpi/pptt.c

> @@ -517,6 +517,43 @@ static int find_acpi_cpu_topology_tag(unsigned int cpu, int level, int flag)

>  	return retval;

>  }

>  

> +/**

> + * check_acpi_cpu_flag() - Determine if CPU node has a flag set

> + * @cpu: Kernel logical CPU number

> + * @rev: The PPTT revision defining the flag

> + * @flag: The flag itself

> + *

> + * Check the node representing a CPU for a given flag.

> + *

> + * Return: -ENOENT if the PPTT doesn't exist, the CPU cannot be found or

> + *	   the table revision isn't new enough.

> + * Otherwise returns flag value

> + */

> +static int check_acpi_cpu_flag(unsigned int cpu, int rev, u32 flag)


Initially, I thought we already have similar function, but I was wrong.

> +{

> +	struct acpi_table_header *table;

> +	acpi_status status;

> +	u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);

> +	struct acpi_pptt_processor *cpu_node = NULL;

> +	int ret = -ENONET;



Unfortunately even ENONET is defined and will silently compile fine, but
I assume you need ENOENT as mentioned in the comment/doc.
> +

> +	status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);

> +	if (ACPI_FAILURE(status)) {

> +		acpi_pptt_warn_missing();

> +		return ret;

> +	}

> +

> +	if (table->revision >= rev)

> +		cpu_node = acpi_find_processor_node(table, acpi_cpu_id);

> +

> +	if (cpu_node)

> +		ret = cpu_node->flags & flag;

> +

> +	acpi_put_table(table);

> +

> +	return ret;

> +}

> +

>  /**

>   * acpi_find_last_cache_level() - Determines the number of cache levels for a PE

>   * @cpu: Kernel logical CPU number

> @@ -581,6 +618,21 @@ int cache_setup_acpi(unsigned int cpu)

>  	return status;

>  }

>  

> +/**

> + * acpi_pptt_cpu_is_thread() - Determine if logical CPU is a thread

> + * @cpu: Kernel logical CPU number

> + *

> + *

> + * Return: 1, a thread

> + *         0, not a thread

> + *         -ENOENT if the PPTT doesn't exist, the CPU cannot be found or

> + *         the table revision isn't new enough.

> + */

> +int acpi_pptt_cpu_is_thread(unsigned int cpu)

> +{

> +	return check_acpi_cpu_flag(cpu, 2, ACPI_PPTT_ACPI_PROCESSOR_IS_THREAD);

> +}

> +

>  /**

>   * find_acpi_cpu_topology() - Determine a unique topology value for a given CPU

>   * @cpu: Kernel logical CPU number

> @@ -641,7 +693,6 @@ int find_acpi_cpu_cache_topology(unsigned int cpu, int level)

>  	return ret;

>  }

>  

> -


Spurious ?

>  /**

>   * find_acpi_cpu_topology_package() - Determine a unique CPU package value

>   * @cpu: Kernel logical CPU number

> diff --git a/include/linux/acpi.h b/include/linux/acpi.h

> index 98440df7fe42..513833233c65 100644

> --- a/include/linux/acpi.h

> +++ b/include/linux/acpi.h

> @@ -1314,10 +1314,15 @@ static inline int lpit_read_residency_count_address(u64 *address)

>  #endif

>  

>  #ifdef CONFIG_ACPI_PPTT

> +int acpi_pptt_cpu_is_thread(unsigned int cpu);

>  int find_acpi_cpu_topology(unsigned int cpu, int level);

>  int find_acpi_cpu_topology_package(unsigned int cpu);

>  int find_acpi_cpu_cache_topology(unsigned int cpu, int level);

>  #else

> +static inline int acpi_pptt_cpu_is_thread(unsigned int cpu)

> +{

> +	return -EINVAL;

> +}

>  static inline int find_acpi_cpu_topology(unsigned int cpu, int level)

>  {

>  	return -EINVAL;

> -- 

> 2.21.0

>
diff mbox series

Patch

diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
index b72e6afaa8fb..6f43a0c05f61 100644
--- a/drivers/acpi/pptt.c
+++ b/drivers/acpi/pptt.c
@@ -517,6 +517,43 @@  static int find_acpi_cpu_topology_tag(unsigned int cpu, int level, int flag)
 	return retval;
 }
 
+/**
+ * check_acpi_cpu_flag() - Determine if CPU node has a flag set
+ * @cpu: Kernel logical CPU number
+ * @rev: The PPTT revision defining the flag
+ * @flag: The flag itself
+ *
+ * Check the node representing a CPU for a given flag.
+ *
+ * Return: -ENOENT if the PPTT doesn't exist, the CPU cannot be found or
+ *	   the table revision isn't new enough.
+ * Otherwise returns flag value
+ */
+static int check_acpi_cpu_flag(unsigned int cpu, int rev, u32 flag)
+{
+	struct acpi_table_header *table;
+	acpi_status status;
+	u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
+	struct acpi_pptt_processor *cpu_node = NULL;
+	int ret = -ENONET;
+
+	status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
+	if (ACPI_FAILURE(status)) {
+		acpi_pptt_warn_missing();
+		return ret;
+	}
+
+	if (table->revision >= rev)
+		cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
+
+	if (cpu_node)
+		ret = cpu_node->flags & flag;
+
+	acpi_put_table(table);
+
+	return ret;
+}
+
 /**
  * acpi_find_last_cache_level() - Determines the number of cache levels for a PE
  * @cpu: Kernel logical CPU number
@@ -581,6 +618,21 @@  int cache_setup_acpi(unsigned int cpu)
 	return status;
 }
 
+/**
+ * acpi_pptt_cpu_is_thread() - Determine if logical CPU is a thread
+ * @cpu: Kernel logical CPU number
+ *
+ *
+ * Return: 1, a thread
+ *         0, not a thread
+ *         -ENOENT if the PPTT doesn't exist, the CPU cannot be found or
+ *         the table revision isn't new enough.
+ */
+int acpi_pptt_cpu_is_thread(unsigned int cpu)
+{
+	return check_acpi_cpu_flag(cpu, 2, ACPI_PPTT_ACPI_PROCESSOR_IS_THREAD);
+}
+
 /**
  * find_acpi_cpu_topology() - Determine a unique topology value for a given CPU
  * @cpu: Kernel logical CPU number
@@ -641,7 +693,6 @@  int find_acpi_cpu_cache_topology(unsigned int cpu, int level)
 	return ret;
 }
 
-
 /**
  * find_acpi_cpu_topology_package() - Determine a unique CPU package value
  * @cpu: Kernel logical CPU number
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 98440df7fe42..513833233c65 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -1314,10 +1314,15 @@  static inline int lpit_read_residency_count_address(u64 *address)
 #endif
 
 #ifdef CONFIG_ACPI_PPTT
+int acpi_pptt_cpu_is_thread(unsigned int cpu);
 int find_acpi_cpu_topology(unsigned int cpu, int level);
 int find_acpi_cpu_topology_package(unsigned int cpu);
 int find_acpi_cpu_cache_topology(unsigned int cpu, int level);
 #else
+static inline int acpi_pptt_cpu_is_thread(unsigned int cpu)
+{
+	return -EINVAL;
+}
 static inline int find_acpi_cpu_topology(unsigned int cpu, int level)
 {
 	return -EINVAL;