This adds /sys/kernel/phyp_dump_active so that kdump init scripts may
look for it and take appropriate action if this file is found.  This
file is only created when phyp_dump has been registered.
Signed-off-by: NManish Ahuja <mahuja@us.ibm.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

This adds a kernel command line option "phyp_dump", which takes a 0/1
value for disabling/ enabling phyp_dump at boot time.  Kdump can use
this on cmdline (phyp_dump=0) to disable phyp-dump during boot when
enabling itself.  This will ensure only one dumping mechanism is active
at any given time.
Signed-off-by: NManish Ahuja <mahuja@us.ibm.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

This tracks the size freed.  For now it does a simple rudimentary
calculation of the ranges freed.  The idea is to keep it simple at the
external shell script level and send in large chunks for now.
Signed-off-by: NManish Ahuja <mahuja@us.ibm.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

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>