drivers/dax/Kconfig

   1 # SPDX-License-Identifier: GPL-2.0-only
   2 config DAX_DRIVER
   3         select DAX
   4         bool
   5
   6 menuconfig DAX
   7         tristate "DAX: direct access to differentiated memory"
   8         select SRCU
   9         default m if NVDIMM_DAX
  10
  11 if DAX
  12
  13 config DEV_DAX
  14         tristate "Device DAX: direct access mapping device"
  15         depends on TRANSPARENT_HUGEPAGE
  16         help
  17           Support raw access to differentiated (persistence, bandwidth,
  18           latency...) memory via an mmap(2) capable character
  19           device.  Platform firmware or a device driver may identify a
  20           platform memory resource that is differentiated from the
  21           baseline memory pool.  Mappings of a /dev/daxX.Y device impose
  22           restrictions that make the mapping behavior deterministic.
  23
  24 config DEV_DAX_PMEM
  25         tristate "PMEM DAX: direct access to persistent memory"
  26         depends on LIBNVDIMM && NVDIMM_DAX && DEV_DAX
  27         default DEV_DAX
  28         help
  29           Support raw access to persistent memory.  Note that this
  30           driver consumes memory ranges allocated and exported by the
  31           libnvdimm sub-system.
  32
  33           Say M if unsure
  34
  35 config DEV_DAX_HMEM
  36         tristate "HMEM DAX: direct access to 'specific purpose' memory"
  37         depends on EFI_SOFT_RESERVE
  38         select NUMA_KEEP_MEMINFO if (NUMA && X86)
  39         default DEV_DAX
  40         help
  41           EFI 2.8 platforms, and others, may advertise 'specific purpose'
  42           memory. For example, a high bandwidth memory pool. The
  43           indication from platform firmware is meant to reserve the
  44           memory from typical usage by default. This driver creates
  45           device-dax instances for these memory ranges, and that also
  46           enables the possibility to assign them to the DEV_DAX_KMEM
  47           driver to override the reservation and add them to kernel
  48           "System RAM" pool.
  49
  50           Say M if unsure.
  51
  52 config DEV_DAX_HMEM_DEVICES
  53         depends on DEV_DAX_HMEM && DAX=y
  54         def_bool y
  55
  56 config DEV_DAX_KMEM
  57         tristate "KMEM DAX: volatile-use of persistent memory"
  58         default DEV_DAX
  59         depends on DEV_DAX
  60         depends on MEMORY_HOTPLUG # for add_memory() and friends
  61         help
  62           Support access to persistent, or other performance
  63           differentiated memory as if it were System RAM. This allows
  64           easier use of persistent memory by unmodified applications, or
  65           adds core kernel memory services to heterogeneous memory types
  66           (HMEM) marked "reserved" by platform firmware.
  67
  68           To use this feature, a DAX device must be unbound from the
  69           device_dax driver and bound to this kmem driver on each boot.
  70
  71           Say N if unsure.
  72
  73 config DEV_DAX_PMEM_COMPAT
  74         tristate "PMEM DAX: support the deprecated /sys/class/dax interface"
  75         depends on m && DEV_DAX_PMEM=m
  76         default DEV_DAX_PMEM
  77         help
  78           Older versions of the libdaxctl library expect to find all
  79           device-dax instances under /sys/class/dax. If libdaxctl in
  80           your distribution is older than v58 say M, otherwise say N.
  81
  82 endif