Implement intelligent backtracing by searching for stack frame creation,
and emitting only return addresses. Use print_hex_dump() to display the
entire binary kernel stack.

Limitation: MMU kernels are not currently able to trace beyond a system trap
(interrupt, syscall, etc.). It is the intent of this patch to provide
infrastructure that can be extended to add this capability later.

Changes from V1:
* Removed checks in find_frame_creation() that prevented location of the frame
  creation instruction in heavily optimized code
* Various formatting/commenting/file location tweaks per review comments
* Dropped Kconfig option to enable STACKTRACE as something logically separate

Signed-off-by: Steven J. Magnani <steve@digidescorp.com>

I found several function which we don't use that's why I am removing them.

Signed-off-by: Michal Simek <monstr@monstr.eu>

The "kstack=" command line parameter is not parsed correctly.
All proper values are interpreted as zero.

Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>

Signed-off-by: Michal Simek <monstr@monstr.eu>

The whole point of the __bad_xchg declaration in
system.h is to give a linker error when a variable
of invalid size is passed to __xchg. The out
of line definition in traps.c defeats this purpose
and does not any value, so remove it here.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michal Simek <monstr@monstr.eu>

CHECK   arch/microblaze/kernel/traps.c
arch/microblaze/kernel/traps.c:37:47: warning: Using plain integer as NULL pointer
CC      arch/microblaze/kernel/traps.o

Signed-off-by: Michal Simek <monstr@monstr.eu>

Reviewed-by: Ingo Molnar <mingo@elte.hu>
Acked-by: John Linn <john.linn@xilinx.com>
Acked-by: Stephen Neuendorffer <stephen.neuendorffer@xilinx.com>
Acked-by: John Williams <john.williams@petalogix.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>