Patchwork [PATCHv7,03/10] acpi/hmat: Parse and report heterogeneous memory

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Submitter Keith Busch
Date Feb. 27, 2019, 10:50 p.m.
Message ID <20190227225038.20438-4-keith.busch@intel.com>
Download mbox | patch
Permalink /patch/737379/
State New
Headers show

Comments

Keith Busch - Feb. 27, 2019, 10:50 p.m.
Systems may provide different memory types and export this information
in the ACPI Heterogeneous Memory Attribute Table (HMAT). Parse these
tables provided by the platform and report the memory access and caching
attributes to the kernel messages.

Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>
---
 drivers/acpi/Kconfig       |   1 +
 drivers/acpi/Makefile      |   1 +
 drivers/acpi/hmat/Kconfig  |   7 ++
 drivers/acpi/hmat/Makefile |   1 +
 drivers/acpi/hmat/hmat.c   | 237 +++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 247 insertions(+)
 create mode 100644 drivers/acpi/hmat/Kconfig
 create mode 100644 drivers/acpi/hmat/Makefile
 create mode 100644 drivers/acpi/hmat/hmat.c
Jonathan Cameron - March 8, 2019, 5:25 p.m.
On Wed, 27 Feb 2019 15:50:31 -0700
Keith Busch <keith.busch@intel.com> wrote:

> Systems may provide different memory types and export this information
> in the ACPI Heterogeneous Memory Attribute Table (HMAT). Parse these
> tables provided by the platform and report the memory access and caching
> attributes to the kernel messages.
> 
> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Signed-off-by: Keith Busch <keith.busch@intel.com>
Hi Keith,

Trivial unused variable that could do with tidying up...

Thanks,

Jonathan

> ---
>  drivers/acpi/Kconfig       |   1 +
>  drivers/acpi/Makefile      |   1 +
>  drivers/acpi/hmat/Kconfig  |   7 ++
>  drivers/acpi/hmat/Makefile |   1 +
>  drivers/acpi/hmat/hmat.c   | 237 +++++++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 247 insertions(+)
>  create mode 100644 drivers/acpi/hmat/Kconfig
>  create mode 100644 drivers/acpi/hmat/Makefile
>  create mode 100644 drivers/acpi/hmat/hmat.c
> 
> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
> index 4e015c77e48e..283ee94224c6 100644
> --- a/drivers/acpi/Kconfig
> +++ b/drivers/acpi/Kconfig
> @@ -475,6 +475,7 @@ config ACPI_REDUCED_HARDWARE_ONLY
>  	  If you are unsure what to do, do not enable this option.
>  
>  source "drivers/acpi/nfit/Kconfig"
> +source "drivers/acpi/hmat/Kconfig"
>  
>  source "drivers/acpi/apei/Kconfig"
>  source "drivers/acpi/dptf/Kconfig"
> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> index bb857421c2e8..5d361e4e3405 100644
> --- a/drivers/acpi/Makefile
> +++ b/drivers/acpi/Makefile
> @@ -80,6 +80,7 @@ obj-$(CONFIG_ACPI_PROCESSOR)	+= processor.o
>  obj-$(CONFIG_ACPI)		+= container.o
>  obj-$(CONFIG_ACPI_THERMAL)	+= thermal.o
>  obj-$(CONFIG_ACPI_NFIT)		+= nfit/
> +obj-$(CONFIG_ACPI_HMAT)		+= hmat/
>  obj-$(CONFIG_ACPI)		+= acpi_memhotplug.o
>  obj-$(CONFIG_ACPI_HOTPLUG_IOAPIC) += ioapic.o
>  obj-$(CONFIG_ACPI_BATTERY)	+= battery.o
> diff --git a/drivers/acpi/hmat/Kconfig b/drivers/acpi/hmat/Kconfig
> new file mode 100644
> index 000000000000..2f7111b7af62
> --- /dev/null
> +++ b/drivers/acpi/hmat/Kconfig
> @@ -0,0 +1,7 @@
> +# SPDX-License-Identifier: GPL-2.0
> +config ACPI_HMAT
> +	bool "ACPI Heterogeneous Memory Attribute Table Support"
> +	depends on ACPI_NUMA
> +	help
> +	 If set, this option has the kernel parse and report the
> +	 platform's ACPI HMAT (Heterogeneous Memory Attributes Table).
> diff --git a/drivers/acpi/hmat/Makefile b/drivers/acpi/hmat/Makefile
> new file mode 100644
> index 000000000000..e909051d3d00
> --- /dev/null
> +++ b/drivers/acpi/hmat/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_ACPI_HMAT) := hmat.o
> diff --git a/drivers/acpi/hmat/hmat.c b/drivers/acpi/hmat/hmat.c
> new file mode 100644
> index 000000000000..99f711420f6d
> --- /dev/null
> +++ b/drivers/acpi/hmat/hmat.c
> @@ -0,0 +1,237 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2019, Intel Corporation.
> + *
> + * Heterogeneous Memory Attributes Table (HMAT) representation
> + *
> + * This program parses and reports the platform's HMAT tables, and registers
> + * the applicable attributes with the node's interfaces.
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/bitops.h>
> +#include <linux/device.h>
> +#include <linux/init.h>
> +#include <linux/list.h>
> +#include <linux/node.h>
> +#include <linux/sysfs.h>
> +
> +static __initdata u8 hmat_revision;
> +
> +static __init const char *hmat_data_type(u8 type)
> +{
> +	switch (type) {
> +	case ACPI_HMAT_ACCESS_LATENCY:
> +		return "Access Latency";
> +	case ACPI_HMAT_READ_LATENCY:
> +		return "Read Latency";
> +	case ACPI_HMAT_WRITE_LATENCY:
> +		return "Write Latency";
> +	case ACPI_HMAT_ACCESS_BANDWIDTH:
> +		return "Access Bandwidth";
> +	case ACPI_HMAT_READ_BANDWIDTH:
> +		return "Read Bandwidth";
> +	case ACPI_HMAT_WRITE_BANDWIDTH:
> +		return "Write Bandwidth";
> +	default:
> +		return "Reserved";
> +	}
> +}
> +
> +static __init const char *hmat_data_type_suffix(u8 type)
> +{
> +	switch (type) {
> +	case ACPI_HMAT_ACCESS_LATENCY:
> +	case ACPI_HMAT_READ_LATENCY:
> +	case ACPI_HMAT_WRITE_LATENCY:
> +		return " nsec";
> +	case ACPI_HMAT_ACCESS_BANDWIDTH:
> +	case ACPI_HMAT_READ_BANDWIDTH:
> +	case ACPI_HMAT_WRITE_BANDWIDTH:
> +		return " MB/s";
> +	default:
> +		return "";
> +	}
> +}
> +
> +static __init u32 hmat_normalize(u16 entry, u64 base, u8 type)
> +{
> +	u32 value;
> +
> +	/*
> +	 * Check for invalid and overflow values
> +	 */
> +	if (entry == 0xffff || !entry)
> +		return 0;
> +	else if (base > (UINT_MAX / (entry)))
> +		return 0;
> +
> +	/*
> +	 * Divide by the base unit for version 1, convert latency from
> +	 * picosenonds to nanoseconds if revision 2.
> +	 */
> +	value = entry * base;
> +	if (hmat_revision == 1) {
> +		if (value < 10)
> +			return 0;
> +		value = DIV_ROUND_UP(value, 10);
> +	} else if (hmat_revision == 2) {
> +		switch (type) {
> +		case ACPI_HMAT_ACCESS_LATENCY:
> +		case ACPI_HMAT_READ_LATENCY:
> +		case ACPI_HMAT_WRITE_LATENCY:
> +			value = DIV_ROUND_UP(value, 1000);
> +			break;
> +		default:
> +			break;
> +		}
> +	}
> +	return value;
> +}
> +
> +static __init int hmat_parse_locality(union acpi_subtable_headers *header,
> +				      const unsigned long end)
> +{
> +	struct acpi_hmat_locality *hmat_loc = (void *)header;
> +	unsigned int init, targ, total_size, ipds, tpds;
> +	u32 *inits, *targs, value;
> +	u16 *entries;
> +	u8 type;
> +
> +	if (hmat_loc->header.length < sizeof(*hmat_loc)) {
> +		pr_notice("HMAT: Unexpected locality header length: %d\n",
> +			 hmat_loc->header.length);
> +		return -EINVAL;
> +	}
> +
> +	type = hmat_loc->data_type;
> +	ipds = hmat_loc->number_of_initiator_Pds;
> +	tpds = hmat_loc->number_of_target_Pds;
> +	total_size = sizeof(*hmat_loc) + sizeof(*entries) * ipds * tpds +
> +		     sizeof(*inits) * ipds + sizeof(*targs) * tpds;
> +	if (hmat_loc->header.length < total_size) {
> +		pr_notice("HMAT: Unexpected locality header length:%d, minimum required:%d\n",
> +			 hmat_loc->header.length, total_size);
> +		return -EINVAL;
> +	}
> +
> +	pr_info("HMAT: Locality: Flags:%02x Type:%s Initiator Domains:%d Target Domains:%d Base:%lld\n",
> +		hmat_loc->flags, hmat_data_type(type), ipds, tpds,
> +		hmat_loc->entry_base_unit);
> +
> +	inits = (u32 *)(hmat_loc + 1);
> +	targs = inits + ipds;
> +	entries = (u16 *)(targs + tpds);
> +	for (init = 0; init < ipds; init++) {
> +		for (targ = 0; targ < tpds; targ++) {
> +			value = hmat_normalize(entries[init * tpds + targ],
> +					       hmat_loc->entry_base_unit,
> +					       type);
> +			pr_info("  Initiator-Target[%d-%d]:%d%s\n",
> +				inits[init], targs[targ], value,
> +				hmat_data_type_suffix(type));
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static __init int hmat_parse_cache(union acpi_subtable_headers *header,
> +				   const unsigned long end)
> +{
> +	struct acpi_hmat_cache *cache = (void *)header;
> +	u32 attrs;
> +
> +	if (cache->header.length < sizeof(*cache)) {
> +		pr_notice("HMAT: Unexpected cache header length: %d\n",
> +			 cache->header.length);
> +		return -EINVAL;
> +	}
> +
> +	attrs = cache->cache_attributes;
> +	pr_info("HMAT: Cache: Domain:%d Size:%llu Attrs:%08x SMBIOS Handles:%d\n",
> +		cache->memory_PD, cache->cache_size, attrs,
> +		cache->number_of_SMBIOShandles);
> +
> +	return 0;
> +}
> +
> +static int __init hmat_parse_address_range(union acpi_subtable_headers *header,
> +					   const unsigned long end)
> +{
> +	struct acpi_hmat_proximity_domain *p = (void *)header;
> +	struct memory_target *target = NULL;

Not used anywhere.

> +
> +	if (p->header.length != sizeof(*p)) {
> +		pr_notice("HMAT: Unexpected address range header length: %d\n",
> +			 p->header.length);
> +		return -EINVAL;
> +	}
> +
> +	if (hmat_revision == 1)
> +		pr_info("HMAT: Memory (%#llx length %#llx) Flags:%04x Processor Domain:%d Memory Domain:%d\n",
> +			p->reserved3, p->reserved4, p->flags, p->processor_PD,
> +			p->memory_PD);
> +	else
> +		pr_info("HMAT: Memory Flags:%04x Processor Domain:%d Memory Domain:%d\n",
> +			p->flags, p->processor_PD, p->memory_PD);
> +
> +	return 0;
> +}
> +
> +static int __init hmat_parse_subtable(union acpi_subtable_headers *header,
> +				      const unsigned long end)
> +{
> +	struct acpi_hmat_structure *hdr = (void *)header;
> +
> +	if (!hdr)
> +		return -EINVAL;
> +
> +	switch (hdr->type) {
> +	case ACPI_HMAT_TYPE_ADDRESS_RANGE:
> +		return hmat_parse_address_range(header, end);
> +	case ACPI_HMAT_TYPE_LOCALITY:
> +		return hmat_parse_locality(header, end);
> +	case ACPI_HMAT_TYPE_CACHE:
> +		return hmat_parse_cache(header, end);
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static __init int hmat_init(void)
> +{
> +	struct acpi_table_header *tbl;
> +	enum acpi_hmat_type i;
> +	acpi_status status;
> +
> +	if (srat_disabled())
> +		return 0;
> +
> +	status = acpi_get_table(ACPI_SIG_HMAT, 0, &tbl);
> +	if (ACPI_FAILURE(status))
> +		return 0;
> +
> +	hmat_revision = tbl->revision;
> +	switch (hmat_revision) {
> +	case 1:
> +	case 2:
> +		break;
> +	default:
> +		pr_notice("Ignoring HMAT: Unknown revision:%d\n", hmat_revision);
> +		goto out_put;
> +	}
> +
> +	for (i = ACPI_HMAT_TYPE_ADDRESS_RANGE; i < ACPI_HMAT_TYPE_RESERVED; i++) {
> +		if (acpi_table_parse_entries(ACPI_SIG_HMAT,
> +					     sizeof(struct acpi_table_hmat), i,
> +					     hmat_parse_subtable, 0) < 0) {
> +			pr_notice("Ignoring HMAT: Invalid table");
> +			goto out_put;
> +		}
> +	}
> +out_put:
> +	acpi_put_table(tbl);
> +	return 0;
> +}
> +subsys_initcall(hmat_init);
Jonathan Cameron - March 11, 2019, 10:28 a.m.
On Wed, 27 Feb 2019 15:50:31 -0700
Keith Busch <keith.busch@intel.com> wrote:

> Systems may provide different memory types and export this information
> in the ACPI Heterogeneous Memory Attribute Table (HMAT). Parse these
> tables provided by the platform and report the memory access and caching
> attributes to the kernel messages.
> 
> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Signed-off-by: Keith Busch <keith.busch@intel.com>
Hi Keith

A few trivial comments in this one. All stuff we can fix if a firmware
runs into the limits of representation.

One other question that comes to mind is:
The move to picoseconds was perhaps optimistic on the part of the
ACPI spec, but do we want to go for future proofing and go with them?
Costs us a few more zeros in a sysfs file after all.  Internal storage
could stay at nano seconds perhaps.

All small things though so either way...

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

> ---
>  drivers/acpi/Kconfig       |   1 +
>  drivers/acpi/Makefile      |   1 +
>  drivers/acpi/hmat/Kconfig  |   7 ++
>  drivers/acpi/hmat/Makefile |   1 +
>  drivers/acpi/hmat/hmat.c   | 237 +++++++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 247 insertions(+)
>  create mode 100644 drivers/acpi/hmat/Kconfig
>  create mode 100644 drivers/acpi/hmat/Makefile
>  create mode 100644 drivers/acpi/hmat/hmat.c
> 
> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
> index 4e015c77e48e..283ee94224c6 100644
> --- a/drivers/acpi/Kconfig
> +++ b/drivers/acpi/Kconfig
> @@ -475,6 +475,7 @@ config ACPI_REDUCED_HARDWARE_ONLY
>  	  If you are unsure what to do, do not enable this option.
>  
>  source "drivers/acpi/nfit/Kconfig"
> +source "drivers/acpi/hmat/Kconfig"
>  
>  source "drivers/acpi/apei/Kconfig"
>  source "drivers/acpi/dptf/Kconfig"
> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> index bb857421c2e8..5d361e4e3405 100644
> --- a/drivers/acpi/Makefile
> +++ b/drivers/acpi/Makefile
> @@ -80,6 +80,7 @@ obj-$(CONFIG_ACPI_PROCESSOR)	+= processor.o
>  obj-$(CONFIG_ACPI)		+= container.o
>  obj-$(CONFIG_ACPI_THERMAL)	+= thermal.o
>  obj-$(CONFIG_ACPI_NFIT)		+= nfit/
> +obj-$(CONFIG_ACPI_HMAT)		+= hmat/
>  obj-$(CONFIG_ACPI)		+= acpi_memhotplug.o
>  obj-$(CONFIG_ACPI_HOTPLUG_IOAPIC) += ioapic.o
>  obj-$(CONFIG_ACPI_BATTERY)	+= battery.o
> diff --git a/drivers/acpi/hmat/Kconfig b/drivers/acpi/hmat/Kconfig
> new file mode 100644
> index 000000000000..2f7111b7af62
> --- /dev/null
> +++ b/drivers/acpi/hmat/Kconfig
> @@ -0,0 +1,7 @@
> +# SPDX-License-Identifier: GPL-2.0
> +config ACPI_HMAT
> +	bool "ACPI Heterogeneous Memory Attribute Table Support"
> +	depends on ACPI_NUMA
> +	help
> +	 If set, this option has the kernel parse and report the
> +	 platform's ACPI HMAT (Heterogeneous Memory Attributes Table).
> diff --git a/drivers/acpi/hmat/Makefile b/drivers/acpi/hmat/Makefile
> new file mode 100644
> index 000000000000..e909051d3d00
> --- /dev/null
> +++ b/drivers/acpi/hmat/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_ACPI_HMAT) := hmat.o
> diff --git a/drivers/acpi/hmat/hmat.c b/drivers/acpi/hmat/hmat.c
> new file mode 100644
> index 000000000000..99f711420f6d
> --- /dev/null
> +++ b/drivers/acpi/hmat/hmat.c
> @@ -0,0 +1,237 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2019, Intel Corporation.
> + *
> + * Heterogeneous Memory Attributes Table (HMAT) representation
> + *
> + * This program parses and reports the platform's HMAT tables, and registers
> + * the applicable attributes with the node's interfaces.
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/bitops.h>
> +#include <linux/device.h>
> +#include <linux/init.h>
> +#include <linux/list.h>
> +#include <linux/node.h>
> +#include <linux/sysfs.h>
> +
> +static __initdata u8 hmat_revision;
> +
> +static __init const char *hmat_data_type(u8 type)
> +{
> +	switch (type) {
> +	case ACPI_HMAT_ACCESS_LATENCY:
> +		return "Access Latency";
> +	case ACPI_HMAT_READ_LATENCY:
> +		return "Read Latency";
> +	case ACPI_HMAT_WRITE_LATENCY:
> +		return "Write Latency";
> +	case ACPI_HMAT_ACCESS_BANDWIDTH:
> +		return "Access Bandwidth";
> +	case ACPI_HMAT_READ_BANDWIDTH:
> +		return "Read Bandwidth";
> +	case ACPI_HMAT_WRITE_BANDWIDTH:
> +		return "Write Bandwidth";
> +	default:
> +		return "Reserved";
> +	}
> +}
> +
> +static __init const char *hmat_data_type_suffix(u8 type)
> +{
> +	switch (type) {
> +	case ACPI_HMAT_ACCESS_LATENCY:
> +	case ACPI_HMAT_READ_LATENCY:
> +	case ACPI_HMAT_WRITE_LATENCY:
> +		return " nsec";
> +	case ACPI_HMAT_ACCESS_BANDWIDTH:
> +	case ACPI_HMAT_READ_BANDWIDTH:
> +	case ACPI_HMAT_WRITE_BANDWIDTH:
> +		return " MB/s";
> +	default:
> +		return "";
> +	}
> +}
> +
> +static __init u32 hmat_normalize(u16 entry, u64 base, u8 type)
> +{
> +	u32 value;
> +
> +	/*
> +	 * Check for invalid and overflow values
> +	 */
> +	if (entry == 0xffff || !entry)
> +		return 0;
> +	else if (base > (UINT_MAX / (entry)))

In this particular case, the issue is not that the value provided is impossible
but rather that the kernel is currently using too small a type to hold it.
If I've understood that right, perhaps a warning here would make sense?

Also, for consistency, U32_MAX.


> +		return 0;
> +
> +	/*
> +	 * Divide by the base unit for version 1, convert latency from
> +	 * picosenonds to nanoseconds if revision 2.
> +	 */
> +	value = entry * base;
> +	if (hmat_revision == 1) {
> +		if (value < 10)
> +			return 0;
> +		value = DIV_ROUND_UP(value, 10);
> +	} else if (hmat_revision == 2) {
> +		switch (type) {
> +		case ACPI_HMAT_ACCESS_LATENCY:
> +		case ACPI_HMAT_READ_LATENCY:
> +		case ACPI_HMAT_WRITE_LATENCY:
> +			value = DIV_ROUND_UP(value, 1000);

In this case our use of a u32 is resulting in a value that is clamped
way below the full u32 range.  Perhaps locally do the computation at
higher precision then clamp down at the end?

> +			break;
> +		default:
> +			break;
> +		}
> +	}
> +	return value;
> +}
> +
> +static __init int hmat_parse_locality(union acpi_subtable_headers *header,
> +				      const unsigned long end)
> +{
> +	struct acpi_hmat_locality *hmat_loc = (void *)header;
> +	unsigned int init, targ, total_size, ipds, tpds;
> +	u32 *inits, *targs, value;
> +	u16 *entries;
> +	u8 type;
> +
> +	if (hmat_loc->header.length < sizeof(*hmat_loc)) {
> +		pr_notice("HMAT: Unexpected locality header length: %d\n",
> +			 hmat_loc->header.length);
> +		return -EINVAL;
> +	}
> +
> +	type = hmat_loc->data_type;
> +	ipds = hmat_loc->number_of_initiator_Pds;
> +	tpds = hmat_loc->number_of_target_Pds;
> +	total_size = sizeof(*hmat_loc) + sizeof(*entries) * ipds * tpds +
> +		     sizeof(*inits) * ipds + sizeof(*targs) * tpds;
> +	if (hmat_loc->header.length < total_size) {

Perhaps overly paranoid, but could we make that a != to catch potential
broken tables?

> +		pr_notice("HMAT: Unexpected locality header length:%d, minimum required:%d\n",
> +			 hmat_loc->header.length, total_size);
> +		return -EINVAL;
> +	}
> +
> +	pr_info("HMAT: Locality: Flags:%02x Type:%s Initiator Domains:%d Target Domains:%d Base:%lld\n",
> +		hmat_loc->flags, hmat_data_type(type), ipds, tpds,
> +		hmat_loc->entry_base_unit);
> +
> +	inits = (u32 *)(hmat_loc + 1);
> +	targs = inits + ipds;
> +	entries = (u16 *)(targs + tpds);
> +	for (init = 0; init < ipds; init++) {
> +		for (targ = 0; targ < tpds; targ++) {
> +			value = hmat_normalize(entries[init * tpds + targ],
> +					       hmat_loc->entry_base_unit,
> +					       type);
> +			pr_info("  Initiator-Target[%d-%d]:%d%s\n",
> +				inits[init], targs[targ], value,
> +				hmat_data_type_suffix(type));
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static __init int hmat_parse_cache(union acpi_subtable_headers *header,
> +				   const unsigned long end)
> +{
> +	struct acpi_hmat_cache *cache = (void *)header;
> +	u32 attrs;
> +
> +	if (cache->header.length < sizeof(*cache)) {
> +		pr_notice("HMAT: Unexpected cache header length: %d\n",
> +			 cache->header.length);
> +		return -EINVAL;
> +	}
> +
> +	attrs = cache->cache_attributes;
> +	pr_info("HMAT: Cache: Domain:%d Size:%llu Attrs:%08x SMBIOS Handles:%d\n",
> +		cache->memory_PD, cache->cache_size, attrs,
> +		cache->number_of_SMBIOShandles);
> +
> +	return 0;
> +}
> +
> +static int __init hmat_parse_address_range(union acpi_subtable_headers *header,
> +					   const unsigned long end)
> +{
> +	struct acpi_hmat_proximity_domain *p = (void *)header;
> +	struct memory_target *target = NULL;
> +
> +	if (p->header.length != sizeof(*p)) {
> +		pr_notice("HMAT: Unexpected address range header length: %d\n",
> +			 p->header.length);
> +		return -EINVAL;
> +	}
> +
> +	if (hmat_revision == 1)
> +		pr_info("HMAT: Memory (%#llx length %#llx) Flags:%04x Processor Domain:%d Memory Domain:%d\n",
> +			p->reserved3, p->reserved4, p->flags, p->processor_PD,
> +			p->memory_PD);
> +	else
> +		pr_info("HMAT: Memory Flags:%04x Processor Domain:%d Memory Domain:%d\n",
> +			p->flags, p->processor_PD, p->memory_PD);
> +
> +	return 0;
> +}
> +
> +static int __init hmat_parse_subtable(union acpi_subtable_headers *header,
> +				      const unsigned long end)
> +{
> +	struct acpi_hmat_structure *hdr = (void *)header;
> +
> +	if (!hdr)
> +		return -EINVAL;
> +
> +	switch (hdr->type) {
> +	case ACPI_HMAT_TYPE_ADDRESS_RANGE:
> +		return hmat_parse_address_range(header, end);
> +	case ACPI_HMAT_TYPE_LOCALITY:
> +		return hmat_parse_locality(header, end);
> +	case ACPI_HMAT_TYPE_CACHE:
> +		return hmat_parse_cache(header, end);
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static __init int hmat_init(void)
> +{
> +	struct acpi_table_header *tbl;
> +	enum acpi_hmat_type i;
> +	acpi_status status;
> +
> +	if (srat_disabled())
> +		return 0;
> +
> +	status = acpi_get_table(ACPI_SIG_HMAT, 0, &tbl);
> +	if (ACPI_FAILURE(status))
> +		return 0;
> +
> +	hmat_revision = tbl->revision;
> +	switch (hmat_revision) {
> +	case 1:
> +	case 2:
> +		break;
> +	default:
> +		pr_notice("Ignoring HMAT: Unknown revision:%d\n", hmat_revision);
> +		goto out_put;
> +	}
> +
> +	for (i = ACPI_HMAT_TYPE_ADDRESS_RANGE; i < ACPI_HMAT_TYPE_RESERVED; i++) {
> +		if (acpi_table_parse_entries(ACPI_SIG_HMAT,
> +					     sizeof(struct acpi_table_hmat), i,
> +					     hmat_parse_subtable, 0) < 0) {
> +			pr_notice("Ignoring HMAT: Invalid table");
> +			goto out_put;
> +		}
> +	}
> +out_put:
> +	acpi_put_table(tbl);
> +	return 0;
> +}
> +subsys_initcall(hmat_init);

Patch

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 4e015c77e48e..283ee94224c6 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -475,6 +475,7 @@  config ACPI_REDUCED_HARDWARE_ONLY
 	  If you are unsure what to do, do not enable this option.
 
 source "drivers/acpi/nfit/Kconfig"
+source "drivers/acpi/hmat/Kconfig"
 
 source "drivers/acpi/apei/Kconfig"
 source "drivers/acpi/dptf/Kconfig"
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index bb857421c2e8..5d361e4e3405 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -80,6 +80,7 @@  obj-$(CONFIG_ACPI_PROCESSOR)	+= processor.o
 obj-$(CONFIG_ACPI)		+= container.o
 obj-$(CONFIG_ACPI_THERMAL)	+= thermal.o
 obj-$(CONFIG_ACPI_NFIT)		+= nfit/
+obj-$(CONFIG_ACPI_HMAT)		+= hmat/
 obj-$(CONFIG_ACPI)		+= acpi_memhotplug.o
 obj-$(CONFIG_ACPI_HOTPLUG_IOAPIC) += ioapic.o
 obj-$(CONFIG_ACPI_BATTERY)	+= battery.o
diff --git a/drivers/acpi/hmat/Kconfig b/drivers/acpi/hmat/Kconfig
new file mode 100644
index 000000000000..2f7111b7af62
--- /dev/null
+++ b/drivers/acpi/hmat/Kconfig
@@ -0,0 +1,7 @@ 
+# SPDX-License-Identifier: GPL-2.0
+config ACPI_HMAT
+	bool "ACPI Heterogeneous Memory Attribute Table Support"
+	depends on ACPI_NUMA
+	help
+	 If set, this option has the kernel parse and report the
+	 platform's ACPI HMAT (Heterogeneous Memory Attributes Table).
diff --git a/drivers/acpi/hmat/Makefile b/drivers/acpi/hmat/Makefile
new file mode 100644
index 000000000000..e909051d3d00
--- /dev/null
+++ b/drivers/acpi/hmat/Makefile
@@ -0,0 +1 @@ 
+obj-$(CONFIG_ACPI_HMAT) := hmat.o
diff --git a/drivers/acpi/hmat/hmat.c b/drivers/acpi/hmat/hmat.c
new file mode 100644
index 000000000000..99f711420f6d
--- /dev/null
+++ b/drivers/acpi/hmat/hmat.c
@@ -0,0 +1,237 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2019, Intel Corporation.
+ *
+ * Heterogeneous Memory Attributes Table (HMAT) representation
+ *
+ * This program parses and reports the platform's HMAT tables, and registers
+ * the applicable attributes with the node's interfaces.
+ */
+
+#include <linux/acpi.h>
+#include <linux/bitops.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/node.h>
+#include <linux/sysfs.h>
+
+static __initdata u8 hmat_revision;
+
+static __init const char *hmat_data_type(u8 type)
+{
+	switch (type) {
+	case ACPI_HMAT_ACCESS_LATENCY:
+		return "Access Latency";
+	case ACPI_HMAT_READ_LATENCY:
+		return "Read Latency";
+	case ACPI_HMAT_WRITE_LATENCY:
+		return "Write Latency";
+	case ACPI_HMAT_ACCESS_BANDWIDTH:
+		return "Access Bandwidth";
+	case ACPI_HMAT_READ_BANDWIDTH:
+		return "Read Bandwidth";
+	case ACPI_HMAT_WRITE_BANDWIDTH:
+		return "Write Bandwidth";
+	default:
+		return "Reserved";
+	}
+}
+
+static __init const char *hmat_data_type_suffix(u8 type)
+{
+	switch (type) {
+	case ACPI_HMAT_ACCESS_LATENCY:
+	case ACPI_HMAT_READ_LATENCY:
+	case ACPI_HMAT_WRITE_LATENCY:
+		return " nsec";
+	case ACPI_HMAT_ACCESS_BANDWIDTH:
+	case ACPI_HMAT_READ_BANDWIDTH:
+	case ACPI_HMAT_WRITE_BANDWIDTH:
+		return " MB/s";
+	default:
+		return "";
+	}
+}
+
+static __init u32 hmat_normalize(u16 entry, u64 base, u8 type)
+{
+	u32 value;
+
+	/*
+	 * Check for invalid and overflow values
+	 */
+	if (entry == 0xffff || !entry)
+		return 0;
+	else if (base > (UINT_MAX / (entry)))
+		return 0;
+
+	/*
+	 * Divide by the base unit for version 1, convert latency from
+	 * picosenonds to nanoseconds if revision 2.
+	 */
+	value = entry * base;
+	if (hmat_revision == 1) {
+		if (value < 10)
+			return 0;
+		value = DIV_ROUND_UP(value, 10);
+	} else if (hmat_revision == 2) {
+		switch (type) {
+		case ACPI_HMAT_ACCESS_LATENCY:
+		case ACPI_HMAT_READ_LATENCY:
+		case ACPI_HMAT_WRITE_LATENCY:
+			value = DIV_ROUND_UP(value, 1000);
+			break;
+		default:
+			break;
+		}
+	}
+	return value;
+}
+
+static __init int hmat_parse_locality(union acpi_subtable_headers *header,
+				      const unsigned long end)
+{
+	struct acpi_hmat_locality *hmat_loc = (void *)header;
+	unsigned int init, targ, total_size, ipds, tpds;
+	u32 *inits, *targs, value;
+	u16 *entries;
+	u8 type;
+
+	if (hmat_loc->header.length < sizeof(*hmat_loc)) {
+		pr_notice("HMAT: Unexpected locality header length: %d\n",
+			 hmat_loc->header.length);
+		return -EINVAL;
+	}
+
+	type = hmat_loc->data_type;
+	ipds = hmat_loc->number_of_initiator_Pds;
+	tpds = hmat_loc->number_of_target_Pds;
+	total_size = sizeof(*hmat_loc) + sizeof(*entries) * ipds * tpds +
+		     sizeof(*inits) * ipds + sizeof(*targs) * tpds;
+	if (hmat_loc->header.length < total_size) {
+		pr_notice("HMAT: Unexpected locality header length:%d, minimum required:%d\n",
+			 hmat_loc->header.length, total_size);
+		return -EINVAL;
+	}
+
+	pr_info("HMAT: Locality: Flags:%02x Type:%s Initiator Domains:%d Target Domains:%d Base:%lld\n",
+		hmat_loc->flags, hmat_data_type(type), ipds, tpds,
+		hmat_loc->entry_base_unit);
+
+	inits = (u32 *)(hmat_loc + 1);
+	targs = inits + ipds;
+	entries = (u16 *)(targs + tpds);
+	for (init = 0; init < ipds; init++) {
+		for (targ = 0; targ < tpds; targ++) {
+			value = hmat_normalize(entries[init * tpds + targ],
+					       hmat_loc->entry_base_unit,
+					       type);
+			pr_info("  Initiator-Target[%d-%d]:%d%s\n",
+				inits[init], targs[targ], value,
+				hmat_data_type_suffix(type));
+		}
+	}
+
+	return 0;
+}
+
+static __init int hmat_parse_cache(union acpi_subtable_headers *header,
+				   const unsigned long end)
+{
+	struct acpi_hmat_cache *cache = (void *)header;
+	u32 attrs;
+
+	if (cache->header.length < sizeof(*cache)) {
+		pr_notice("HMAT: Unexpected cache header length: %d\n",
+			 cache->header.length);
+		return -EINVAL;
+	}
+
+	attrs = cache->cache_attributes;
+	pr_info("HMAT: Cache: Domain:%d Size:%llu Attrs:%08x SMBIOS Handles:%d\n",
+		cache->memory_PD, cache->cache_size, attrs,
+		cache->number_of_SMBIOShandles);
+
+	return 0;
+}
+
+static int __init hmat_parse_address_range(union acpi_subtable_headers *header,
+					   const unsigned long end)
+{
+	struct acpi_hmat_proximity_domain *p = (void *)header;
+	struct memory_target *target = NULL;
+
+	if (p->header.length != sizeof(*p)) {
+		pr_notice("HMAT: Unexpected address range header length: %d\n",
+			 p->header.length);
+		return -EINVAL;
+	}
+
+	if (hmat_revision == 1)
+		pr_info("HMAT: Memory (%#llx length %#llx) Flags:%04x Processor Domain:%d Memory Domain:%d\n",
+			p->reserved3, p->reserved4, p->flags, p->processor_PD,
+			p->memory_PD);
+	else
+		pr_info("HMAT: Memory Flags:%04x Processor Domain:%d Memory Domain:%d\n",
+			p->flags, p->processor_PD, p->memory_PD);
+
+	return 0;
+}
+
+static int __init hmat_parse_subtable(union acpi_subtable_headers *header,
+				      const unsigned long end)
+{
+	struct acpi_hmat_structure *hdr = (void *)header;
+
+	if (!hdr)
+		return -EINVAL;
+
+	switch (hdr->type) {
+	case ACPI_HMAT_TYPE_ADDRESS_RANGE:
+		return hmat_parse_address_range(header, end);
+	case ACPI_HMAT_TYPE_LOCALITY:
+		return hmat_parse_locality(header, end);
+	case ACPI_HMAT_TYPE_CACHE:
+		return hmat_parse_cache(header, end);
+	default:
+		return -EINVAL;
+	}
+}
+
+static __init int hmat_init(void)
+{
+	struct acpi_table_header *tbl;
+	enum acpi_hmat_type i;
+	acpi_status status;
+
+	if (srat_disabled())
+		return 0;
+
+	status = acpi_get_table(ACPI_SIG_HMAT, 0, &tbl);
+	if (ACPI_FAILURE(status))
+		return 0;
+
+	hmat_revision = tbl->revision;
+	switch (hmat_revision) {
+	case 1:
+	case 2:
+		break;
+	default:
+		pr_notice("Ignoring HMAT: Unknown revision:%d\n", hmat_revision);
+		goto out_put;
+	}
+
+	for (i = ACPI_HMAT_TYPE_ADDRESS_RANGE; i < ACPI_HMAT_TYPE_RESERVED; i++) {
+		if (acpi_table_parse_entries(ACPI_SIG_HMAT,
+					     sizeof(struct acpi_table_hmat), i,
+					     hmat_parse_subtable, 0) < 0) {
+			pr_notice("Ignoring HMAT: Invalid table");
+			goto out_put;
+		}
+	}
+out_put:
+	acpi_put_table(tbl);
+	return 0;
+}
+subsys_initcall(hmat_init);