The compilation of kexec/kdump seems to be broken for x86_64.  Remove the
dependency of kexec on CONFIG_IA32_EMULATION.
Signed-off-by: NFernando Vazquez <fernando@intellilink.co.jp>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

- Saving the cpu registers of all cpus before booting in to the crash
  kernel.

- crash_setup_regs will save the registers of the cpu on which panic has
  occured.  One of the concerns ppc64 folks raised is that after capturing the
  register states, one should not pop the current call frame and push new one.
   Hence it has been inlined.  More call frames later get pushed on to stack
  (machine_crash_shutdown() and machine_kexec()), but one will not want to
  backtrace those.

- Not very sure about the CFI annotations.  With this patch I am getting
  decent backtrace with gdb.  Assuming, compiler has generated enough
  debugging information for crash_kexec().  Coding crash_setup_regs() in pure
  assembly makes it tricky because then it can not be inlined and we don't
  want to return back after capturing register states we don't want to pop
  this call frame.

- Saving the non-panicing cpus registers will be done in the NMI handler
  while shooting down them in machine_crash_shutdown.

- Introducing CRASH_DUMP option in Kconfig for x86_64.
Signed-off-by: NMurali M Chakravarthy <muralim@in.ibm.com>
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

- In case of system crash, current state of cpu registers is saved in memory
  in elf note format.  So far memory for storing elf notes was being allocated
  statically for NR_CPUS.

- This patch introduces dynamic allocation of memory for storing elf notes.
  It uses alloc_percpu() interface.  This should lead to better memory usage.

- Introduced based on Andi Kleen's and Eric W. Biederman's suggestions.

- This patch also moves memory allocation for elf notes from architecture
  dependent portion to architecture independent portion.  Now crash_notes is
  architecture independent.  The whole idea is that size of memory to be
  allocated per cpu (MAX_NOTE_BYTES) can be architecture dependent and
  allocation of this memory can be architecture independent.
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

o Following patch exports kexec global variable "crash_notes" to user space
  through sysfs as kernel attribute in /sys/kernel.
Signed-off-by: NManeesh Soni <maneesh@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This is the x86_64 implementation of machine kexec.  32bit compatibility
support has been implemented, and machine_kexec has been enhanced to not care
about the changing internal kernel paget table structures.

From: Alexander Nyberg <alexn@dsv.su.se>

      build fix
Signed-off-by: NEric Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>