1# SPDX-License-Identifier: GPL-2.0-only
2config DAX_DRIVER
3	select DAX
4	bool
5
6menuconfig DAX
7	tristate "DAX: direct access to differentiated memory"
8	select SRCU
9	default m if NVDIMM_DAX
10
11if DAX
12
13config 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
24config 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
35config DEV_DAX_KMEM
36	tristate "KMEM DAX: volatile-use of persistent memory"
37	default DEV_DAX
38	depends on DEV_DAX
39	depends on MEMORY_HOTPLUG # for add_memory() and friends
40	help
41	  Support access to persistent memory as if it were RAM.  This
42	  allows easier use of persistent memory by unmodified
43	  applications.
44
45	  To use this feature, a DAX device must be unbound from the
46	  device_dax driver (PMEM DAX) and bound to this kmem driver
47	  on each boot.
48
49	  Say N if unsure.
50
51config DEV_DAX_PMEM_COMPAT
52	tristate "PMEM DAX: support the deprecated /sys/class/dax interface"
53	depends on m && DEV_DAX_PMEM=m
54	default DEV_DAX_PMEM
55	help
56	  Older versions of the libdaxctl library expect to find all
57	  device-dax instances under /sys/class/dax. If libdaxctl in
58	  your distribution is older than v58 say M, otherwise say N.
59
60endif
61