diff mbox series

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

Message ID 20190503232407.37195-5-jeremy.linton@arm.com (mailing list archive)
State Not Applicable, archived
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(+)

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__ */