kdb: core for kgdb back end (1 of 2)

kdb: core for kgdb back end (1 of 2)

This patch contains only the kdb core.  Because the change set was
large, it was split.  The next patch in the series includes the
instrumentation into the core kernel which are mainly helper functions
for kdb.

This work is directly derived from kdb v4.4 found at:

ftp://oss.sgi.com/projects/kdb/download/v4.4/

The kdb internals have been re-organized to make them mostly platform
independent and to connect everything to the debug core which is used by
gdbstub (which has long been known as kgdb).

The original version of kdb was 58,000 lines worth of changes to
support x86.  From that implementation only the kdb shell, and basic
commands for memory access, runcontrol, lsmod, and dmesg where carried
forward.

This is a generic implementation which aims to cover all the current
architectures using the kgdb core: ppc, arm, x86, mips, sparc, sh and
blackfin.  More archictectures can be added by implementing the
architecture specific kgdb functions.

[[email protected]: Compile fix with hugepages enabled]
[[email protected]: Clean breakpoint code renaming kdba_ -> kdb_]
[[email protected]: fix new line after printing registers]
[[email protected]: Remove the concept of global vs. local breakpoints]
[[email protected]: Rework kdb_si_swapinfo to use more generic name]
[[email protected]: fix the information dump macros, remove 'arch' from the names]
[[email protected]: include fixup to include linux/slab.h]

CC: [email protected]
Signed-off-by: Jason Wessel <[email protected]>
Signed-off-by: Martin Hicks <[email protected]>