| # SPDX-License-Identifier: GPL-2.0-only | |
| config DAX_DRIVER | |
| select DAX | |
| bool | |
| menuconfig DAX | |
| tristate "DAX: direct access to differentiated memory" | |
| select SRCU | |
| 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 && X86) | |
| default DEV_DAX | |
| 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_HMEM_DEVICES | |
| depends on DEV_DAX_HMEM && DAX=y | |
| def_bool y | |
| config DEV_DAX_KMEM | |
| tristate "KMEM DAX: volatile-use of persistent memory" | |
| 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. | |
| config DEV_DAX_PMEM_COMPAT | |
| tristate "PMEM DAX: support the deprecated /sys/class/dax interface" | |
| depends on m && DEV_DAX_PMEM=m | |
| default DEV_DAX_PMEM | |
| help | |
| Older versions of the libdaxctl library expect to find all | |
| device-dax instances under /sys/class/dax. If libdaxctl in | |
| your distribution is older than v58 say M, otherwise say N. | |
| endif |