[Patch, microblaze]: Add initial port of linux gdbserver

add gdb_proc_service_h to gdbserver microblaze-linux

gdbserver needs to initialise the microblaze registers

other archs use this step to run a *_arch_setup() to carry out all
architecture specific setup - may need to add in future

 * add linux-ptrace.o to gdbserver configure
 * gdb/configure.tgt: Set build_gdbserver=yes
 * Update breakpoint opcode
 * fix segfault on connecting gdbserver
 * add microblaze_linux_memory_remove_breakpoint
 * add set_solib_svr4_fetch_link_map_offsets
 * add set_gdbarch_fetch_tls_load_module_address
 * Force reading of r0 as 0, prevent stores

Signed-off-by: David Holsgrove <david.holsgrove@petalogix.com>
Signed-off-by: Nathan Rossi <nathan.rossi@petalogix.com>
[Patch, microblaze]: Add slr and shr regs and little-endian breakpoint

Signed-off-by: David Holsgrove <david.holsgrove@xilinx.com>
[Patch, microblaze]: Added Backtrace support to GDB

Added backtrace support without debugging information.

Earlier backtrace used to work only when debug information is available.
Previous pc & sp values are calculated incorrectly due to which backtrace
was failing.

In this patch, previous frame sp & pc values are calculated correctly
in microblaze_frame_cache function and supplied them to
microblaze_frame_prev_register function

Signed-off-by:nagaraju <nmekala@xilix.com>
[Patch, microblaze]: Initial support for native gdb

microblaze: Follow PPC method of getting setting registers
using PTRACE PEEK/POKE

Signed-off-by: David Holsgrove <david.holsgrove@petalogix.com>
[Patch, microblaze]: Robustify inline function support

Signed-off-by: Edgar E. Iglesias <edgar@axis.com>
[Patch, microblaze]: Fix debug message when register is unavailable

Signed-off-by: Nathan Rossi <nathan.rossi@petalogix.com>
[LOCAL]: Disable the warning message for eh_frame_hdr

Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
[LOCAL]: Fix relaxation of assembler resolved references
[LOCAL]: Fixup debug_loc sections after linker relaxation

Adds a new reloctype R_MICROBLAZE_32_NONE, used for passing
reloc info from the assembler to the linker when the linker
manages to fully resolve a local symbol reference.

This is a workaround for design flaws in the assembler to
linker interface with regards to linker relaxation.

Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Signed-off-by: David Holsgrove <david.holsgrove@xilinx.com>
[LOCAL]: upstream change to garbage collection sweep causes mb regression

Upstream change for PR13177 now clears the def_regular during gc_sweep of a
section. (All other archs in binutils/bfd/elf32-*.c received an update
to a warning about unresolvable relocations - this warning is not present
in binutils/bfd/elf32-microblaze.c, but this warning check would not
prevent the error being seen)

The visible issue with this change is when running a c++ application
in Petalinux which links libstdc++.so for exception handling it segfaults
on execution.

This does not occur if static linking libstdc++.a, so its during the
relocations for a shared lib with garbage collection this occurs

Signed-off-by: David Holsgrove <david.holsgrove@xilinx.com>
[LOCAL]: Add Support for cfi asm insn

Signed-off-by: David Holsgrove <david.holsgrove@xilinx.com>