Allow for setting kernel breakpoints in our remote kgdb

Revert to working state

Max kernel address is end of kernel

branches: 1.17.28; 1.17.30;
support building on arm

branches: 1.16.6; 1.16.10;
Fix /dev/kmem access and make vmstat(1) `work'. Not sure all the results are
indeed valid or correct but at least it shows them without coredumping or
coredumping the kernel.

Clarify comment about PAGER_MAP_DEFAULT_SIZE

Bump pager map default size since KVM is not that tight anymore

Rework NetBSD/usermode pmap fixing some oddities that were left over from
earlier times when we were forced to run PIE executables and were forced to
use a KVM above the kernel.

Fix VM_MAX_ADDRESS that is NOT the max address BUT the max userland address
Fix VM_MAX_KERNEL_ADDRESS that is the absolute max address accesable by the
kernel...

branches: 1.11.2; 1.11.6;
define __USE_TOPDOWN_VM

Revert.

Add checks for architectures that need a check for VM_MIN_ADDRESS

Swap userland code and kvm spaces so that userland lives from VM_MIN_ADDRESS
to VM_MAXUSER_ADDRESS and KVM is above that.

Note that the userspace is surrounded by a configurable amount of
non-accessible barrier space to prevent accidental out-of-boundaries access
even when reading.

Fix vmparam's definitions to the new style

kmem_data_start is no longer needed

build fixes for netbsd-5 and i386

Start NetBSD/usermode's pmap. Its using a temp file as a physical memory
backup and that should be documented in the code. A physical address is thus a
file offset(!) and a virtual address is a `normal' accesible address.

Still to do: various misc functions and pmap_extract() in special.

Credits also go to Ben Harris for his work on the Acorn26 pmap that followed
the Daemon Book recommendation for systems without real page tables on wich
this implementation is modelled after.

Drop 3rd and 4th clauses. OK jmcneill (copyright holder).

branches: 1.2.2; 1.2.4; 1.2.6; 1.2.8; 1.2.18;
To make NetBSD/userland to boot on i386 choose some defaults in vmparam.h
since for i386 they are defined in page size constants wich NetBSD/userland
doesn't know yet. Also undefine ptrace's __HAVE_PTRACE_MACHDEP since i386
has that but NetBSD/userland not.

Import work-in-progress NetBSD/usermode port.