1.\" Copyright (c) 2019 The FreeBSD Foundation, Inc. 2.\" 3.\" This documentation was written by 4.\" Konstantin Belousov <kib@FreeBSD.org> under sponsorship 5.\" from the FreeBSD Foundation. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" $FreeBSD$ 29.\" 30.Dd August 23, 2019 31.Dt NVDIMM 4 32.Os 33.Sh NAME 34.Nm nvdimm 35.Nd ACPI NVDIMM driver 36.Sh SYNOPSIS 37To load the driver as a module at boot, place the following line in 38.Xr loader.conf 5 : 39.Bd -literal -offset indent 40nvdimm_load="YES" 41.Ed 42.Sh DESCRIPTION 43.Bf -symbolic 44Note: 45The 46.Nm 47driver is under development and has some important limitations 48described below. 49.Ef 50.Pp 51The 52.Nm 53driver provides access to Non-Volatile DIMM (NVDIMM) persistent memory 54devices, which are ACPI-enumerated under the root NVDIMM device 55with a 56.Va _HID 57of 58.Dv ACPI0012 59and in the 60.Dv NFIT 61table. 62.Pp 63For each System Physical Address (SPA) Range described by NFIT, a 64device node 65.Pa /dev/nvdimm_spaNNN 66is created, where 67.Dv NNN 68is the SPA position in the table. 69The node can be used to 70.Xr read 2 , 71.Xr write 2 , 72or 73.Xr mmap 2 74the device. 75.Pp 76Also, for each SPA, the geom provider 77.Pa spaNNN 78is created, which can be used to create a conventional filesystem (e.g. 79by 80.Xr newfs 8 ) 81and 82.Xr mount 8 83it as any storage volume. 84Content accessible by 85.Pa /dev/nvdimm_spaNNN 86and 87.Pa /dev/spaNNN 88is coherent. 89.Sh SEE ALSO 90.Xr ACPI 4 , 91.Xr GEOM 4 , 92.Xr geom 8 , 93.Xr mount 8 , 94.Xr newfs 8 , 95.Xr disk 9 96.Sh HISTORY 97The 98.Nm 99driver first appeared in 100.Fx 12.0 . 101.Sh AUTHORS 102.An -nosplit 103The 104.Nm 105driver was originally written by 106.An Konstantin Belousov Aq Mt kib@FreeBSD.org , 107and then updated by 108.An D. Scott Phillips Aq Mt scottph@FreeBSD.org . 109.Sh BUGS 110The 111.Nm 112driver does not utilize the Block Window interface, so if the write to 113NVDIMM was interrupted due to a system crash or power outage, 114the corresponding page might be left in partially updated state. 115.Pp 116There is no support for Device-Specific Methods (DSM), used to report and 117control the device health and wearing. 118.Pp 119The driver depends on the 120.Xr pmap_largemap 9 121pmap interface, which is currently only implemented on amd64. 122The interface can be only reasonable implemented on 64bit architectures. 123