# SPDX-License-Identifier: GPL-2.0-onlymenuconfig DAX	tristate "DAX: direct access to differentiated memory"	default m if NVDIMM_DAX if DAX config DEV_DAX	tristate "Device DAX: direct access mapping device"	depends on TRANSPARENT_HUGEPAGE	help	  Support raw access to differentiated (persistence, bandwidth,	  latency...) memory via an mmap(2) capable character	  device.  Platform firmware or a device driver may identify a	  platform memory resource that is differentiated from the	  baseline memory pool.  Mappings of a /dev/daxX.Y device impose	  restrictions that make the mapping behavior deterministic. config DEV_DAX_PMEM	tristate "PMEM DAX: direct access to persistent memory"	depends on LIBNVDIMM && NVDIMM_DAX && DEV_DAX	default DEV_DAX	help	  Support raw access to persistent memory.  Note that this	  driver consumes memory ranges allocated and exported by the	  libnvdimm sub-system. 	  Say M if unsure config DEV_DAX_HMEM	tristate "HMEM DAX: direct access to 'specific purpose' memory"	depends on EFI_SOFT_RESERVE	select NUMA_KEEP_MEMINFO if NUMA_MEMBLKS	default DEV_DAX	depends on CXL_ACPI || !CXL_ACPI	depends on CXL_PCI || !CXL_PCI	depends on CXL_BUS || !CXL_BUS	help	  EFI 2.8 platforms, and others, may advertise 'specific purpose'	  memory. For example, a high bandwidth memory pool. The	  indication from platform firmware is meant to reserve the	  memory from typical usage by default. This driver creates	  device-dax instances for these memory ranges, and that also	  enables the possibility to assign them to the DEV_DAX_KMEM	  driver to override the reservation and add them to kernel	  "System RAM" pool. 	  Say M if unsure. config DEV_DAX_CXL	tristate "CXL DAX: direct access to CXL RAM regions"	depends on CXL_BUS && CXL_REGION && DEV_DAX	default CXL_REGION && DEV_DAX	depends on DEV_DAX_HMEM || !DEV_DAX_HMEM	help	  CXL RAM regions are either mapped by platform-firmware	  and published in the initial system-memory map as "System RAM", mapped	  by platform-firmware as "Soft Reserved", or dynamically provisioned	  after boot by the CXL driver. In the latter two cases a device-dax	  instance is created to access that unmapped-by-default address range.	  Per usual it can remain as dedicated access via a device interface, or	  converted to "System RAM" via the dax_kmem facility. config DEV_DAX_HMEM_DEVICES	depends on DEV_DAX_HMEM && DAX	def_bool y config DEV_DAX_FSDEV	tristate	depends on DEV_DAX && FS_DAX	default DEV_DAX config DEV_DAX_KMEM	tristate "KMEM DAX: map dax-devices as System-RAM"	default DEV_DAX	depends on DEV_DAX	depends on MEMORY_HOTPLUG # for add_memory() and friends	help	  Support access to persistent, or other performance	  differentiated memory as if it were System RAM. This allows	  easier use of persistent memory by unmodified applications, or	  adds core kernel memory services to heterogeneous memory types	  (HMEM) marked "reserved" by platform firmware. 	  To use this feature, a DAX device must be unbound from the	  device_dax driver and bound to this kmem driver on each boot. 	  Say N if unsure. endif