MEM(4) | Device Drivers Manual (hppa) | MEM(4) |
mem
, kmem
—
mem* at mainbus0
mem
driver controls and restricts access to the
systems memory by the hardware buses and the processor.
It also provides an interface to userland through the special files /dev/mem and /dev/kmem. Physical memory is accessed through /dev/mem, while kernel virtual memory is accessed through /dev/kmem. Access to kernel virtual addresses not currently mapped to memory will fail. On hppa, the physical memory range is always contiguous and starts at address 0; kernel virtual memory begins at address 0 as well.
The writeability of the /dev/mem and /dev/kmem special files are controlled by the system securelevel in addition to the filesystem permissions.
mem
driver originates from
OpenBSD. It was ported to NetBSD
1.6 by Matthew Fredette.
mem
or hppa/cpu(4) device
probe.
February 17, 2017 | NetBSD 9.4 |