diff mbox series

[v3,4/5] arm_pmu: acpi: spe: Add initial MADT/SPE probing

Message ID 20190503232407.37195-5-jeremy.linton@arm.com
State Superseded
Headers show
Series arm64: SPE ACPI enablement | expand

Commit Message

Jeremy Linton May 3, 2019, 11:24 p.m. UTC
ACPI 6.3 adds additional fields to the MADT GICC
structure to describe SPE PPI's. We pick these out
of the cached reference to the madt_gicc structure
similarly to the core PMU code. We then create a platform
device referring to the IRQ and let the user/module loader
decide whether to load the SPE driver.

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

---
 arch/arm64/include/asm/acpi.h |  3 ++
 drivers/perf/Kconfig          |  5 +++
 drivers/perf/arm_pmu_acpi.c   | 76 +++++++++++++++++++++++++++++++++++
 include/linux/perf/arm_pmu.h  |  2 +
 4 files changed, 86 insertions(+)

-- 
2.21.0

Comments

John Garry May 8, 2019, 11:18 a.m. UTC | #1
On 04/05/2019 00:24, Jeremy Linton wrote:
> ACPI 6.3 adds additional fields to the MADT GICC

> structure to describe SPE PPI's. We pick these out

> of the cached reference to the madt_gicc structure

> similarly to the core PMU code. We then create a platform

> device referring to the IRQ and let the user/module loader

> decide whether to load the SPE driver.

>

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

> ---

>  arch/arm64/include/asm/acpi.h |  3 ++

>  drivers/perf/Kconfig          |  5 +++

>  drivers/perf/arm_pmu_acpi.c   | 76 +++++++++++++++++++++++++++++++++++

>  include/linux/perf/arm_pmu.h  |  2 +

>  4 files changed, 86 insertions(+)

>

> diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h

> index 7628efbe6c12..d10399b9f998 100644

> --- a/arch/arm64/include/asm/acpi.h

> +++ b/arch/arm64/include/asm/acpi.h

> @@ -41,6 +41,9 @@

>  	(!(entry) || (entry)->header.length < ACPI_MADT_GICC_MIN_LENGTH || \

>  	(unsigned long)(entry) + (entry)->header.length > (end))

>

> +#define ACPI_MADT_GICC_SPE  (ACPI_OFFSET(struct acpi_madt_generic_interrupt, \

> +	spe_interrupt) + sizeof(u16))

> +

>  /* Basic configuration for ACPI */

>  #ifdef	CONFIG_ACPI

>  pgprot_t __acpi_get_mem_attribute(phys_addr_t addr);

> diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig

> index af9bc178495d..bc2647c64c9d 100644

> --- a/drivers/perf/Kconfig

> +++ b/drivers/perf/Kconfig

> @@ -52,6 +52,11 @@ config ARM_PMU_ACPI

>  	depends on ARM_PMU && ACPI

>  	def_bool y

>

> +config ARM_SPE_ACPI


Is it possible to just use this check in arm_pmu_acpi.c instead, to 
avoid introducing another config here:

if defined(CONFIG_ARM_SPE_PMU)

> +	depends on ARM_PMU_ACPI && ARM_SPE_PMU

> +	def_bool y

> +

> +


nit: extra line

>  config ARM_DSU_PMU

>  	tristate "ARM DynamIQ Shared Unit (DSU) PMU"

>  	depends on ARM64

> diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c

> index 0f197516d708..b0244e1e8c91 100644

> --- a/drivers/perf/arm_pmu_acpi.c

> +++ b/drivers/perf/arm_pmu_acpi.c

> @@ -74,6 +74,80 @@ static void arm_pmu_acpi_unregister_irq(int cpu)

>  	acpi_unregister_gsi(gsi);

>  }

>

> +#ifdef CONFIG_ARM_SPE_ACPI

> +static struct resource spe_resources[] = {

> +	{

> +		/* irq */

> +		.flags          = IORESOURCE_IRQ,

> +	}

> +};

> +

> +static struct platform_device spe_dev = {

> +	.name = ARMV8_SPE_PDEV_NAME,

> +	.id = -1,

> +	.resource = spe_resources,

> +	.num_resources = ARRAY_SIZE(spe_resources)

> +};

> +

> +/*

> + * For lack of a better place, hook the normal PMU MADT walk

> + * and create a SPE device if we detect a recent MADT with

> + * a homogeneous PPI mapping.

> + */

> +static int arm_spe_acpi_register_device(void)

> +{

> +	int cpu, ret, irq;

> +	int hetid;


nit: not sure why you use multiple lines here

> +	u16 gsi = 0;

> +	bool first = true;

> +


nit: extra line, and gicc could be declared within the loop in which 
it's used to limit scope.

> +	struct acpi_madt_generic_interrupt *gicc;

> +

> +	/*

> +	 * sanity check all the GICC tables for the same interrupt number

> +	 * for now we only support homogeneous ACPI/SPE machines.

> +	 */

> +	for_each_possible_cpu(cpu) {

> +		gicc = acpi_cpu_get_madt_gicc(cpu);

> +

> +		if (gicc->header.length < ACPI_MADT_GICC_SPE)

> +			return -ENODEV;

> +		if (first) {

> +			gsi = gicc->spe_interrupt;

> +			if (!gsi)

> +				return -ENODEV;

> +			hetid = find_acpi_cpu_topology_hetero_id(cpu);

> +			first = false;

> +		} else if ((gsi != gicc->spe_interrupt) ||

> +			   (hetid != find_acpi_cpu_topology_hetero_id(cpu))) {

> +			pr_warn("ACPI: SPE must be homogeneous\n");

> +			return -EINVAL;

> +		}

> +	}

> +

> +	irq = acpi_register_gsi(NULL, gsi, ACPI_LEVEL_SENSITIVE,

> +				ACPI_ACTIVE_HIGH);

> +	if (irq < 0) {


is irq == 0 a valid Linux IRQ number? From checking 
irq_create_fw_spec_mapping(), it does not seem to be.

> +		pr_warn("ACPI: SPE Unable to register interrupt: %d\n", gsi);

> +		return irq;

> +	}

> +

> +	spe_resources[0].start = irq;

> +	ret = platform_device_register(&spe_dev);

> +	if (ret < 0) {

> +		pr_warn("ACPI: SPE: Unable to register device\n");

> +		acpi_unregister_gsi(gsi);

> +	}

> +

> +	return ret;

> +}

> +#else

> +static inline int arm_spe_acpi_register_device(void)

> +{

> +	return -ENODEV;

> +}

> +#endif /* CONFIG_ARM_SPE_ACPI */

> +

>  static int arm_pmu_acpi_parse_irqs(void)

>  {

>  	int irq, cpu, irq_cpu, err;

> @@ -279,6 +353,8 @@ static int arm_pmu_acpi_init(void)

>  	if (acpi_disabled)

>  		return 0;

>

> +	arm_spe_acpi_register_device(); /* failures are expected */

> +

>  	ret = arm_pmu_acpi_parse_irqs();

>  	if (ret)

>  		return ret;

> diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h

> index 4641e850b204..784bc58f165a 100644

> --- a/include/linux/perf/arm_pmu.h

> +++ b/include/linux/perf/arm_pmu.h

> @@ -175,4 +175,6 @@ void armpmu_free_irq(int irq, int cpu);

>

>  #endif /* CONFIG_ARM_PMU */

>

> +#define ARMV8_SPE_PDEV_NAME "arm,spe-v1"

> +

>  #endif /* __ARM_PMU_H__ */

>


Thanks!
Jeremy Linton May 8, 2019, 8:04 p.m. UTC | #2
Hi,

Thanks for taking a look at this,

On 5/8/19 6:18 AM, John Garry wrote:
e> On 04/05/2019 00:24, Jeremy Linton wrote:
>> ACPI 6.3 adds additional fields to the MADT GICC

>> structure to describe SPE PPI's. We pick these out

>> of the cached reference to the madt_gicc structure

>> similarly to the core PMU code. We then create a platform

>> device referring to the IRQ and let the user/module loader

>> decide whether to load the SPE driver.

>>

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

>> ---

>>  arch/arm64/include/asm/acpi.h |  3 ++

>>  drivers/perf/Kconfig          |  5 +++

>>  drivers/perf/arm_pmu_acpi.c   | 76 +++++++++++++++++++++++++++++++++++

>>  include/linux/perf/arm_pmu.h  |  2 +

>>  4 files changed, 86 insertions(+)

>>

>> diff --git a/arch/arm64/include/asm/acpi.h 

>> b/arch/arm64/include/asm/acpi.h

>> index 7628efbe6c12..d10399b9f998 100644

>> --- a/arch/arm64/include/asm/acpi.h

>> +++ b/arch/arm64/include/asm/acpi.h

>> @@ -41,6 +41,9 @@

>>      (!(entry) || (entry)->header.length < ACPI_MADT_GICC_MIN_LENGTH || \

>>      (unsigned long)(entry) + (entry)->header.length > (end))

>>

>> +#define ACPI_MADT_GICC_SPE  (ACPI_OFFSET(struct 

>> acpi_madt_generic_interrupt, \

>> +    spe_interrupt) + sizeof(u16))

>> +

>>  /* Basic configuration for ACPI */

>>  #ifdef    CONFIG_ACPI

>>  pgprot_t __acpi_get_mem_attribute(phys_addr_t addr);

>> diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig

>> index af9bc178495d..bc2647c64c9d 100644

>> --- a/drivers/perf/Kconfig

>> +++ b/drivers/perf/Kconfig

>> @@ -52,6 +52,11 @@ config ARM_PMU_ACPI

>>      depends on ARM_PMU && ACPI

>>      def_bool y

>>

>> +config ARM_SPE_ACPI

> 

> Is it possible to just use this check in arm_pmu_acpi.c instead, to 

> avoid introducing another config here:

> 

> if defined(CONFIG_ARM_SPE_PMU)


I'm sure it works, if this is preferred, sure..


> 

>> +    depends on ARM_PMU_ACPI && ARM_SPE_PMU

>> +    def_bool y

>> +

>> +

> 

> nit: extra line

> 

>>  config ARM_DSU_PMU

>>      tristate "ARM DynamIQ Shared Unit (DSU) PMU"

>>      depends on ARM64

>> diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c

>> index 0f197516d708..b0244e1e8c91 100644

>> --- a/drivers/perf/arm_pmu_acpi.c

>> +++ b/drivers/perf/arm_pmu_acpi.c

>> @@ -74,6 +74,80 @@ static void arm_pmu_acpi_unregister_irq(int cpu)

>>      acpi_unregister_gsi(gsi);

>>  }

>>

>> +#ifdef CONFIG_ARM_SPE_ACPI

>> +static struct resource spe_resources[] = {

>> +    {

>> +        /* irq */

>> +        .flags          = IORESOURCE_IRQ,

>> +    }

>> +};

>> +

>> +static struct platform_device spe_dev = {

>> +    .name = ARMV8_SPE_PDEV_NAME,

>> +    .id = -1,

>> +    .resource = spe_resources,

>> +    .num_resources = ARRAY_SIZE(spe_resources)

>> +};

>> +

>> +/*

>> + * For lack of a better place, hook the normal PMU MADT walk

>> + * and create a SPE device if we detect a recent MADT with

>> + * a homogeneous PPI mapping.

>> + */

>> +static int arm_spe_acpi_register_device(void)

>> +{

>> +    int cpu, ret, irq;

>> +    int hetid;

>  > nit: not sure why you use multiple lines here


Functional grouping, but I should probably re-arrange them...


> 

>> +    u16 gsi = 0;

>> +    bool first = true;

>> +

> 

> nit: extra line, and gicc could be declared within the loop in which 

> it's used to limit scope.

> 

>> +    struct acpi_madt_generic_interrupt *gicc;

>> +

>> +    /*

>> +     * sanity check all the GICC tables for the same interrupt number

>> +     * for now we only support homogeneous ACPI/SPE machines.

>> +     */

>> +    for_each_possible_cpu(cpu) {

>> +        gicc = acpi_cpu_get_madt_gicc(cpu);

>> +

>> +        if (gicc->header.length < ACPI_MADT_GICC_SPE)

>> +            return -ENODEV;

>> +        if (first) {

>> +            gsi = gicc->spe_interrupt;

>> +            if (!gsi)

>> +                return -ENODEV;

>> +            hetid = find_acpi_cpu_topology_hetero_id(cpu);

>> +            first = false;

>> +        } else if ((gsi != gicc->spe_interrupt) ||

>> +               (hetid != find_acpi_cpu_topology_hetero_id(cpu))) {

>> +            pr_warn("ACPI: SPE must be homogeneous\n");

>> +            return -EINVAL;

>> +        }

>> +    }

>> +

>> +    irq = acpi_register_gsi(NULL, gsi, ACPI_LEVEL_SENSITIVE,

>> +                ACPI_ACTIVE_HIGH);

>> +    if (irq < 0) {

> 

> is irq == 0 a valid Linux IRQ number? From checking 

> irq_create_fw_spec_mapping(), it does not seem to be.


I think this is a bit of a trick question, acpi_register_gsi's 
commented/implementations/etc seem to assume that 0 may be a valid 
interrupt, for example

"
  * Returns: a valid linux IRQ number on success
  *          -EINVAL on failure
"

And various pieces of code have >=0  valid IRQ checks. So... I don't 
think its a problem written this way. It leaves the door open for a 
possible 0 despite that likely not being a valid interrupt.. :)


> 

>> +        pr_warn("ACPI: SPE Unable to register interrupt: %d\n", gsi);

>> +        return irq;

>> +    }

>> +

>> +    spe_resources[0].start = irq;

>> +    ret = platform_device_register(&spe_dev);

>> +    if (ret < 0) {

>> +        pr_warn("ACPI: SPE: Unable to register device\n");

>> +        acpi_unregister_gsi(gsi);

>> +    }

>> +

>> +    return ret;

>> +}

>> +#else

>> +static inline int arm_spe_acpi_register_device(void)

>> +{

>> +    return -ENODEV;

>> +}

>> +#endif /* CONFIG_ARM_SPE_ACPI */

>> +

>>  static int arm_pmu_acpi_parse_irqs(void)

>>  {

>>      int irq, cpu, irq_cpu, err;

>> @@ -279,6 +353,8 @@ static int arm_pmu_acpi_init(void)

>>      if (acpi_disabled)

>>          return 0;

>>

>> +    arm_spe_acpi_register_device(); /* failures are expected */

>> +

>>      ret = arm_pmu_acpi_parse_irqs();

>>      if (ret)

>>          return ret;

>> diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h

>> index 4641e850b204..784bc58f165a 100644

>> --- a/include/linux/perf/arm_pmu.h

>> +++ b/include/linux/perf/arm_pmu.h

>> @@ -175,4 +175,6 @@ void armpmu_free_irq(int irq, int cpu);

>>

>>  #endif /* CONFIG_ARM_PMU */

>>

>> +#define ARMV8_SPE_PDEV_NAME "arm,spe-v1"

>> +

>>  #endif /* __ARM_PMU_H__ */

>>

> 

> Thanks!

> 

> 

>
Sudeep Holla June 7, 2019, 9:57 a.m. UTC | #3
On Fri, May 03, 2019 at 06:24:06PM -0500, Jeremy Linton wrote:
> ACPI 6.3 adds additional fields to the MADT GICC

> structure to describe SPE PPI's. We pick these out

> of the cached reference to the madt_gicc structure

> similarly to the core PMU code. We then create a platform

> device referring to the IRQ and let the user/module loader

> decide whether to load the SPE driver.

> 

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

> ---

>  arch/arm64/include/asm/acpi.h |  3 ++

>  drivers/perf/Kconfig          |  5 +++

>  drivers/perf/arm_pmu_acpi.c   | 76 +++++++++++++++++++++++++++++++++++

>  include/linux/perf/arm_pmu.h  |  2 +

>  4 files changed, 86 insertions(+)

> 

> diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h

> index 7628efbe6c12..d10399b9f998 100644

> --- a/arch/arm64/include/asm/acpi.h

> +++ b/arch/arm64/include/asm/acpi.h

> @@ -41,6 +41,9 @@

>  	(!(entry) || (entry)->header.length < ACPI_MADT_GICC_MIN_LENGTH || \

>  	(unsigned long)(entry) + (entry)->header.length > (end))

>  

> +#define ACPI_MADT_GICC_SPE  (ACPI_OFFSET(struct acpi_madt_generic_interrupt, \

> +	spe_interrupt) + sizeof(u16))

> +

>  /* Basic configuration for ACPI */

>  #ifdef	CONFIG_ACPI

>  pgprot_t __acpi_get_mem_attribute(phys_addr_t addr);

> diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig

> index af9bc178495d..bc2647c64c9d 100644

> --- a/drivers/perf/Kconfig

> +++ b/drivers/perf/Kconfig

> @@ -52,6 +52,11 @@ config ARM_PMU_ACPI

>  	depends on ARM_PMU && ACPI

>  	def_bool y

>  

> +config ARM_SPE_ACPI

> +	depends on ARM_PMU_ACPI && ARM_SPE_PMU

> +	def_bool y

> +

> +

>  config ARM_DSU_PMU

>  	tristate "ARM DynamIQ Shared Unit (DSU) PMU"

>  	depends on ARM64

> diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c

> index 0f197516d708..b0244e1e8c91 100644

> --- a/drivers/perf/arm_pmu_acpi.c

> +++ b/drivers/perf/arm_pmu_acpi.c

> @@ -74,6 +74,80 @@ static void arm_pmu_acpi_unregister_irq(int cpu)

>  	acpi_unregister_gsi(gsi);

>  }

>  

> +#ifdef CONFIG_ARM_SPE_ACPI

> +static struct resource spe_resources[] = {

> +	{

> +		/* irq */

> +		.flags          = IORESOURCE_IRQ,

> +	}

> +};

> +

> +static struct platform_device spe_dev = {

> +	.name = ARMV8_SPE_PDEV_NAME,

> +	.id = -1,

> +	.resource = spe_resources,

> +	.num_resources = ARRAY_SIZE(spe_resources)

> +};

> +

> +/*

> + * For lack of a better place, hook the normal PMU MADT walk

> + * and create a SPE device if we detect a recent MADT with

> + * a homogeneous PPI mapping.

> + */

> +static int arm_spe_acpi_register_device(void)

> +{

> +	int cpu, ret, irq;

> +	int hetid;

> +	u16 gsi = 0;

> +	bool first = true;

> +

> +	struct acpi_madt_generic_interrupt *gicc;

> +

> +	/*

> +	 * sanity check all the GICC tables for the same interrupt number

> +	 * for now we only support homogeneous ACPI/SPE machines.

> +	 */

> +	for_each_possible_cpu(cpu) {

> +		gicc = acpi_cpu_get_madt_gicc(cpu);

> +

> +		if (gicc->header.length < ACPI_MADT_GICC_SPE)

> +			return -ENODEV;

> +		if (first) {

> +			gsi = gicc->spe_interrupt;

> +			if (!gsi)

> +				return -ENODEV;

> +			hetid = find_acpi_cpu_topology_hetero_id(cpu);

> +			first = false;

> +		} else if ((gsi != gicc->spe_interrupt) ||

> +			   (hetid != find_acpi_cpu_topology_hetero_id(cpu))) {


Sorry, I should have noticed this in patch 2 itself. Won't this break for
multi-socket system ? The hetid in that case will be package id, no ?

Otherwise the patch looks good.

--
Regards,
Sudeep
Jeremy Linton June 7, 2019, 1:28 p.m. UTC | #4
Hi,

On 6/7/19 4:57 AM, Sudeep Holla wrote:
> On Fri, May 03, 2019 at 06:24:06PM -0500, Jeremy Linton wrote:

>> ACPI 6.3 adds additional fields to the MADT GICC

>> structure to describe SPE PPI's. We pick these out

>> of the cached reference to the madt_gicc structure

>> similarly to the core PMU code. We then create a platform

>> device referring to the IRQ and let the user/module loader

>> decide whether to load the SPE driver.

>>

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

>> ---

>>   arch/arm64/include/asm/acpi.h |  3 ++

>>   drivers/perf/Kconfig          |  5 +++

>>   drivers/perf/arm_pmu_acpi.c   | 76 +++++++++++++++++++++++++++++++++++

>>   include/linux/perf/arm_pmu.h  |  2 +

>>   4 files changed, 86 insertions(+)

>>

>> diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h

>> index 7628efbe6c12..d10399b9f998 100644

>> --- a/arch/arm64/include/asm/acpi.h

>> +++ b/arch/arm64/include/asm/acpi.h

>> @@ -41,6 +41,9 @@

>>   	(!(entry) || (entry)->header.length < ACPI_MADT_GICC_MIN_LENGTH || \

>>   	(unsigned long)(entry) + (entry)->header.length > (end))

>>   

>> +#define ACPI_MADT_GICC_SPE  (ACPI_OFFSET(struct acpi_madt_generic_interrupt, \

>> +	spe_interrupt) + sizeof(u16))

>> +

>>   /* Basic configuration for ACPI */

>>   #ifdef	CONFIG_ACPI

>>   pgprot_t __acpi_get_mem_attribute(phys_addr_t addr);

>> diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig

>> index af9bc178495d..bc2647c64c9d 100644

>> --- a/drivers/perf/Kconfig

>> +++ b/drivers/perf/Kconfig

>> @@ -52,6 +52,11 @@ config ARM_PMU_ACPI

>>   	depends on ARM_PMU && ACPI

>>   	def_bool y

>>   

>> +config ARM_SPE_ACPI

>> +	depends on ARM_PMU_ACPI && ARM_SPE_PMU

>> +	def_bool y

>> +

>> +

>>   config ARM_DSU_PMU

>>   	tristate "ARM DynamIQ Shared Unit (DSU) PMU"

>>   	depends on ARM64

>> diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c

>> index 0f197516d708..b0244e1e8c91 100644

>> --- a/drivers/perf/arm_pmu_acpi.c

>> +++ b/drivers/perf/arm_pmu_acpi.c

>> @@ -74,6 +74,80 @@ static void arm_pmu_acpi_unregister_irq(int cpu)

>>   	acpi_unregister_gsi(gsi);

>>   }

>>   

>> +#ifdef CONFIG_ARM_SPE_ACPI

>> +static struct resource spe_resources[] = {

>> +	{

>> +		/* irq */

>> +		.flags          = IORESOURCE_IRQ,

>> +	}

>> +};

>> +

>> +static struct platform_device spe_dev = {

>> +	.name = ARMV8_SPE_PDEV_NAME,

>> +	.id = -1,

>> +	.resource = spe_resources,

>> +	.num_resources = ARRAY_SIZE(spe_resources)

>> +};

>> +

>> +/*

>> + * For lack of a better place, hook the normal PMU MADT walk

>> + * and create a SPE device if we detect a recent MADT with

>> + * a homogeneous PPI mapping.

>> + */

>> +static int arm_spe_acpi_register_device(void)

>> +{

>> +	int cpu, ret, irq;

>> +	int hetid;

>> +	u16 gsi = 0;

>> +	bool first = true;

>> +

>> +	struct acpi_madt_generic_interrupt *gicc;

>> +

>> +	/*

>> +	 * sanity check all the GICC tables for the same interrupt number

>> +	 * for now we only support homogeneous ACPI/SPE machines.

>> +	 */

>> +	for_each_possible_cpu(cpu) {

>> +		gicc = acpi_cpu_get_madt_gicc(cpu);

>> +

>> +		if (gicc->header.length < ACPI_MADT_GICC_SPE)

>> +			return -ENODEV;

>> +		if (first) {

>> +			gsi = gicc->spe_interrupt;

>> +			if (!gsi)

>> +				return -ENODEV;

>> +			hetid = find_acpi_cpu_topology_hetero_id(cpu);

>> +			first = false;

>> +		} else if ((gsi != gicc->spe_interrupt) ||

>> +			   (hetid != find_acpi_cpu_topology_hetero_id(cpu))) {

> 

> Sorry, I should have noticed this in patch 2 itself. Won't this break for

> multi-socket system ? The hetid in that case will be package id, no ?


Your assuming a PPTT with multiple trees, one for each socket? Yes it 
breaks in that case, and is what I was complaining about in the cover 
letter because there won't be a common node with the IDENTICAL flag set. 
OTOH, I think it works fine for multi-socket given a single tree where 
the root has IDENTICAL set (I did some very light testing on such a 
machine).

I don't think there is a solution to this problem that won't break in 
the case of a heterogeneous machine with multiple sockets populated with 
differing cores.

> 

> Otherwise the patch looks good. 

> 

> --

> Regards,

> Sudeep

>
Sudeep Holla June 7, 2019, 1:37 p.m. UTC | #5
On Fri, Jun 07, 2019 at 08:28:04AM -0500, Jeremy Linton wrote:
> Hi,

> 

> On 6/7/19 4:57 AM, Sudeep Holla wrote:

> > On Fri, May 03, 2019 at 06:24:06PM -0500, Jeremy Linton wrote:

> > > ACPI 6.3 adds additional fields to the MADT GICC

> > > structure to describe SPE PPI's. We pick these out

> > > of the cached reference to the madt_gicc structure

> > > similarly to the core PMU code. We then create a platform

> > > device referring to the IRQ and let the user/module loader

> > > decide whether to load the SPE driver.

> > > 

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

> > > ---

> > >   arch/arm64/include/asm/acpi.h |  3 ++

> > >   drivers/perf/Kconfig          |  5 +++

> > >   drivers/perf/arm_pmu_acpi.c   | 76 +++++++++++++++++++++++++++++++++++

> > >   include/linux/perf/arm_pmu.h  |  2 +

> > >   4 files changed, 86 insertions(+)

> > > 

> > > diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h

> > > index 7628efbe6c12..d10399b9f998 100644

> > > --- a/arch/arm64/include/asm/acpi.h

> > > +++ b/arch/arm64/include/asm/acpi.h

> > > @@ -41,6 +41,9 @@

> > >   	(!(entry) || (entry)->header.length < ACPI_MADT_GICC_MIN_LENGTH || \

> > >   	(unsigned long)(entry) + (entry)->header.length > (end))

> > > +#define ACPI_MADT_GICC_SPE  (ACPI_OFFSET(struct acpi_madt_generic_interrupt, \

> > > +	spe_interrupt) + sizeof(u16))

> > > +

> > >   /* Basic configuration for ACPI */

> > >   #ifdef	CONFIG_ACPI

> > >   pgprot_t __acpi_get_mem_attribute(phys_addr_t addr);

> > > diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig

> > > index af9bc178495d..bc2647c64c9d 100644

> > > --- a/drivers/perf/Kconfig

> > > +++ b/drivers/perf/Kconfig

> > > @@ -52,6 +52,11 @@ config ARM_PMU_ACPI

> > >   	depends on ARM_PMU && ACPI

> > >   	def_bool y

> > > +config ARM_SPE_ACPI

> > > +	depends on ARM_PMU_ACPI && ARM_SPE_PMU

> > > +	def_bool y

> > > +

> > > +

> > >   config ARM_DSU_PMU

> > >   	tristate "ARM DynamIQ Shared Unit (DSU) PMU"

> > >   	depends on ARM64

> > > diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c

> > > index 0f197516d708..b0244e1e8c91 100644

> > > --- a/drivers/perf/arm_pmu_acpi.c

> > > +++ b/drivers/perf/arm_pmu_acpi.c

> > > @@ -74,6 +74,80 @@ static void arm_pmu_acpi_unregister_irq(int cpu)

> > >   	acpi_unregister_gsi(gsi);

> > >   }

> > > +#ifdef CONFIG_ARM_SPE_ACPI

> > > +static struct resource spe_resources[] = {

> > > +	{

> > > +		/* irq */

> > > +		.flags          = IORESOURCE_IRQ,

> > > +	}

> > > +};

> > > +

> > > +static struct platform_device spe_dev = {

> > > +	.name = ARMV8_SPE_PDEV_NAME,

> > > +	.id = -1,

> > > +	.resource = spe_resources,

> > > +	.num_resources = ARRAY_SIZE(spe_resources)

> > > +};

> > > +

> > > +/*

> > > + * For lack of a better place, hook the normal PMU MADT walk

> > > + * and create a SPE device if we detect a recent MADT with

> > > + * a homogeneous PPI mapping.

> > > + */

> > > +static int arm_spe_acpi_register_device(void)

> > > +{

> > > +	int cpu, ret, irq;

> > > +	int hetid;

> > > +	u16 gsi = 0;

> > > +	bool first = true;

> > > +

> > > +	struct acpi_madt_generic_interrupt *gicc;

> > > +

> > > +	/*

> > > +	 * sanity check all the GICC tables for the same interrupt number

> > > +	 * for now we only support homogeneous ACPI/SPE machines.

> > > +	 */

> > > +	for_each_possible_cpu(cpu) {

> > > +		gicc = acpi_cpu_get_madt_gicc(cpu);

> > > +

> > > +		if (gicc->header.length < ACPI_MADT_GICC_SPE)

> > > +			return -ENODEV;

> > > +		if (first) {

> > > +			gsi = gicc->spe_interrupt;

> > > +			if (!gsi)

> > > +				return -ENODEV;

> > > +			hetid = find_acpi_cpu_topology_hetero_id(cpu);

> > > +			first = false;

> > > +		} else if ((gsi != gicc->spe_interrupt) ||

> > > +			   (hetid != find_acpi_cpu_topology_hetero_id(cpu))) {

> > 

> > Sorry, I should have noticed this in patch 2 itself. Won't this break for

> > multi-socket system ? The hetid in that case will be package id, no ?

> 

> Your assuming a PPTT with multiple trees, one for each socket? Yes it breaks

> in that case, and is what I was complaining about in the cover letter

> because there won't be a common node with the IDENTICAL flag set. OTOH, I

> think it works fine for multi-socket given a single tree where the root has

> IDENTICAL set (I did some very light testing on such a machine).

>


Ah OK, so you are saying such system must have root with IDENTICAL flag
set. Sounds fine, but is there any way to check that ? It's not mandated
right. At least, I didn't have when I hacked up PPTT for Juno and no one
complains(iasl/uefi/linux). But yes that's a different problem, at-least
we know how to fix such PPTT topology.

> I don't think there is a solution to this problem that won't break in the

> case of a heterogeneous machine with multiple sockets populated with

> differing cores.

>


Agreed, I was worried about only about case, but having root node is
feasible solution.

--
Regards,
Sudeep
diff mbox series

Patch

diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
index 7628efbe6c12..d10399b9f998 100644
--- a/arch/arm64/include/asm/acpi.h
+++ b/arch/arm64/include/asm/acpi.h
@@ -41,6 +41,9 @@ 
 	(!(entry) || (entry)->header.length < ACPI_MADT_GICC_MIN_LENGTH || \
 	(unsigned long)(entry) + (entry)->header.length > (end))
 
+#define ACPI_MADT_GICC_SPE  (ACPI_OFFSET(struct acpi_madt_generic_interrupt, \
+	spe_interrupt) + sizeof(u16))
+
 /* Basic configuration for ACPI */
 #ifdef	CONFIG_ACPI
 pgprot_t __acpi_get_mem_attribute(phys_addr_t addr);
diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig
index af9bc178495d..bc2647c64c9d 100644
--- a/drivers/perf/Kconfig
+++ b/drivers/perf/Kconfig
@@ -52,6 +52,11 @@  config ARM_PMU_ACPI
 	depends on ARM_PMU && ACPI
 	def_bool y
 
+config ARM_SPE_ACPI
+	depends on ARM_PMU_ACPI && ARM_SPE_PMU
+	def_bool y
+
+
 config ARM_DSU_PMU
 	tristate "ARM DynamIQ Shared Unit (DSU) PMU"
 	depends on ARM64
diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c
index 0f197516d708..b0244e1e8c91 100644
--- a/drivers/perf/arm_pmu_acpi.c
+++ b/drivers/perf/arm_pmu_acpi.c
@@ -74,6 +74,80 @@  static void arm_pmu_acpi_unregister_irq(int cpu)
 	acpi_unregister_gsi(gsi);
 }
 
+#ifdef CONFIG_ARM_SPE_ACPI
+static struct resource spe_resources[] = {
+	{
+		/* irq */
+		.flags          = IORESOURCE_IRQ,
+	}
+};
+
+static struct platform_device spe_dev = {
+	.name = ARMV8_SPE_PDEV_NAME,
+	.id = -1,
+	.resource = spe_resources,
+	.num_resources = ARRAY_SIZE(spe_resources)
+};
+
+/*
+ * For lack of a better place, hook the normal PMU MADT walk
+ * and create a SPE device if we detect a recent MADT with
+ * a homogeneous PPI mapping.
+ */
+static int arm_spe_acpi_register_device(void)
+{
+	int cpu, ret, irq;
+	int hetid;
+	u16 gsi = 0;
+	bool first = true;
+
+	struct acpi_madt_generic_interrupt *gicc;
+
+	/*
+	 * sanity check all the GICC tables for the same interrupt number
+	 * for now we only support homogeneous ACPI/SPE machines.
+	 */
+	for_each_possible_cpu(cpu) {
+		gicc = acpi_cpu_get_madt_gicc(cpu);
+
+		if (gicc->header.length < ACPI_MADT_GICC_SPE)
+			return -ENODEV;
+		if (first) {
+			gsi = gicc->spe_interrupt;
+			if (!gsi)
+				return -ENODEV;
+			hetid = find_acpi_cpu_topology_hetero_id(cpu);
+			first = false;
+		} else if ((gsi != gicc->spe_interrupt) ||
+			   (hetid != find_acpi_cpu_topology_hetero_id(cpu))) {
+			pr_warn("ACPI: SPE must be homogeneous\n");
+			return -EINVAL;
+		}
+	}
+
+	irq = acpi_register_gsi(NULL, gsi, ACPI_LEVEL_SENSITIVE,
+				ACPI_ACTIVE_HIGH);
+	if (irq < 0) {
+		pr_warn("ACPI: SPE Unable to register interrupt: %d\n", gsi);
+		return irq;
+	}
+
+	spe_resources[0].start = irq;
+	ret = platform_device_register(&spe_dev);
+	if (ret < 0) {
+		pr_warn("ACPI: SPE: Unable to register device\n");
+		acpi_unregister_gsi(gsi);
+	}
+
+	return ret;
+}
+#else
+static inline int arm_spe_acpi_register_device(void)
+{
+	return -ENODEV;
+}
+#endif /* CONFIG_ARM_SPE_ACPI */
+
 static int arm_pmu_acpi_parse_irqs(void)
 {
 	int irq, cpu, irq_cpu, err;
@@ -279,6 +353,8 @@  static int arm_pmu_acpi_init(void)
 	if (acpi_disabled)
 		return 0;
 
+	arm_spe_acpi_register_device(); /* failures are expected */
+
 	ret = arm_pmu_acpi_parse_irqs();
 	if (ret)
 		return ret;
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index 4641e850b204..784bc58f165a 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -175,4 +175,6 @@  void armpmu_free_irq(int irq, int cpu);
 
 #endif /* CONFIG_ARM_PMU */
 
+#define ARMV8_SPE_PDEV_NAME "arm,spe-v1"
+
 #endif /* __ARM_PMU_H__ */