This adds routines to
a. invalidate dump
b. calculate region that is reserved and needs to be freed.  This is
   exported through sysfs interface.

Unregister has been removed for now as it wasn't being used.
Signed-off-by: NManish Ahuja <mahuja@us.ibm.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Provide some basic debugging support.
Signed-off-by: NManish Ahuja <mahuja@us.ibm.com>
Signed-off-by: NLinas Vepstas <linasvepstas@gmail.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Set up the actual dump header, register it with the hypervisor.
Signed-off-by: NManish Ahuja <mahuja@us.ibm.com>
Signed-off-by: NLinas Vepstas <linasvepstas@gmail.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Check to see if there actually is data from a previously
crashed kernel waiting.  If so, allow user-space tools to
grab the data (by reading /proc/kcore).  When user-space
finishes dumping a section, it must release that memory
by writing to sysfs. For example,

  echo "0x40000000 0x10000000" > /sys/kernel/release_region

will release 256MB starting at the 1GB.  The released memory
becomes free for general use.
Signed-off-by: NLinas Vepstas <linasvepstas@gmail.com>
Signed-off-by: NManish Ahuja <mahuja@us.ibm.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Initial patch for reserving memory in early boot, and freeing it
later.  If the previous boot had ended with a crash, the reserved
memory would contain a copy of the crashed kernel data.
Signed-off-by: NManish Ahuja <mahuja@us.ibm.com>
Signed-off-by: NLinas Vepstas <linasvepstas@gmail.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>