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         default DEV_DAX
  39         help
  40           EFI 2.8 platforms, and others, may advertise 'specific purpose'
  41           memory. For example, a high bandwidth memory pool. The
  42           indication from platform firmware is meant to reserve the
  43           memory from typical usage by default. This driver creates
  44           device-dax instances for these memory ranges, and that also
  45           enables the possibility to assign them to the DEV_DAX_KMEM
  46           driver to override the reservation and add them to kernel
  47           "System RAM" pool.
  48
  49           Say M if unsure.
  50
  51 config DEV_DAX_KMEM
  52         tristate "KMEM DAX: volatile-use of persistent memory"
  53         default DEV_DAX
  54         depends on DEV_DAX
  55         depends on MEMORY_HOTPLUG # for add_memory() and friends
  56         help
  57           Support access to persistent, or other performance
  58           differentiated memory as if it were System RAM. This allows
  59           easier use of persistent memory by unmodified applications, or
  60           adds core kernel memory services to heterogeneous memory types
  61           (HMEM) marked "reserved" by platform firmware.
  62
  63           To use this feature, a DAX device must be unbound from the
  64           device_dax driver and bound to this kmem driver on each boot.
  65
  66           Say N if unsure.
  67
  68 config DEV_DAX_PMEM_COMPAT
  69         tristate "PMEM DAX: support the deprecated /sys/class/dax interface"
  70         depends on m && DEV_DAX_PMEM=m
  71         default DEV_DAX_PMEM
  72         help
  73           Older versions of the libdaxctl library expect to find all
  74           device-dax instances under /sys/class/dax. If libdaxctl in
  75           your distribution is older than v58 say M, otherwise say N.
  76
  77 endif