tracing: MIPS: add misc fixups and cleanups

From: Wu Zhangjin <[email protected]>

This patchset adds misc fixups and cleanups for Ftrace of MIPS:

+ Fix the support of 32bit support with -mmcount-ra-address of gcc 4.5
o tracing: MIPS: mcount.S: Fix the argument passing of the 32bit support with gcc 4.5, The argument is passed by $12 in 32bit, not t0.
o tracing: MIPS: Fixup of the 32bit support with -mmcount-ra-address For 32bit kernel, the offset of "b 1f" should be 5 instructions, not only 4.

+ Speedup the dynamic function tracer
o tracing: MIPS: Reduce the overhead of dynamic Function Tracer In the old implementation, we have encode the 'nop' instruction and the instruction of calling to mcount at run-time, which may add some overhead. We reduce this overhead via encoding them when initializing the dynamic function tracer.

+ Lots of cleanups
o The other patches.

----------------
v6 -> v7:

o Apply the feedback from David Daney:
define a macro MCOUNT_RA_ADDRESS_REG instead of the magic number $12 for the patch "tracing: MIPS: mcount.S: Fix the argument passing of the 32bit
support with gcc 4.5"

v5 -> v6:

o splits up the old v5 revision into several patches to make the maintainer happier to review it.

Regards,
Wu Zhangjin

Wu Zhangjin (9):
tracing: MIPS: mcount.S: merge the same continuous #ifdefs
tracing: MIPS: mcount.S: cleanup the arguments of
prepare_ftrace_return
tracing: MIPS: mcount.S: cleanup of the comments
tracing: MIPS: mcount.S: Fix the argument passing of the 32bit
support with gcc 4.5
tracing: MIPS: Fixup of the 32bit support with -mmcount-ra-address
tracing: MIPS: cleanup of the instructions
tracing: MIPS: Reduce the overhead of dynamic Function Tracer
tracing: MIPS: cleanup of function graph tracer
tracing: MIPS: cleanup of the address space checking

 arch/mips/kernel/ftrace.c |  184 +++++++++++++++++++++++++++------------------
 arch/mips/kernel/mcount.S |   55 ++++++++-----
 2 files changed, 146 insertions(+), 93 deletions(-)