1 # SPDX-License-Identifier: GPL-2.0-only
3 tristate "DAX: direct access to differentiated memory"
4 default m if NVDIMM_DAX
9 tristate "Device DAX: direct access mapping device"
10 depends on TRANSPARENT_HUGEPAGE
12 Support raw access to differentiated (persistence, bandwidth,
13 latency...) memory via an mmap(2) capable character
14 device. Platform firmware or a device driver may identify a
15 platform memory resource that is differentiated from the
16 baseline memory pool. Mappings of a /dev/daxX.Y device impose
17 restrictions that make the mapping behavior deterministic.
20 tristate "PMEM DAX: direct access to persistent memory"
21 depends on LIBNVDIMM && NVDIMM_DAX && DEV_DAX
24 Support raw access to persistent memory. Note that this
25 driver consumes memory ranges allocated and exported by the
31 tristate "HMEM DAX: direct access to 'specific purpose' memory"
32 depends on EFI_SOFT_RESERVE
33 select NUMA_KEEP_MEMINFO if (NUMA && X86)
36 EFI 2.8 platforms, and others, may advertise 'specific purpose'
37 memory. For example, a high bandwidth memory pool. The
38 indication from platform firmware is meant to reserve the
39 memory from typical usage by default. This driver creates
40 device-dax instances for these memory ranges, and that also
41 enables the possibility to assign them to the DEV_DAX_KMEM
42 driver to override the reservation and add them to kernel
47 config DEV_DAX_HMEM_DEVICES
48 depends on DEV_DAX_HMEM && DAX=y
52 tristate "KMEM DAX: volatile-use of persistent memory"
55 depends on MEMORY_HOTPLUG # for add_memory() and friends
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.
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.