[RFC PATCH 0/3] objtool: Add mcount sub-command

[Sathvika Vasireddy]

This patchset adds support to implement 'objtool mcount' command.

Right now, objtool is built if CONFIG_STACK_VALIDATION is enabled.
And, '__mcount_loc' section is generated by objtool when --mcount 
option is passed to check sub-command. 

For architectures to be able to generate '__mcount_loc' section
without having to do stack validation, introduce 'mcount' as
a sub-command to objtool. This way, objtool is built for mcount 
if CONFIG_FTRACE_MCOUNT_USE_OBJTOOL is enabled. Additionally, 
architectures can select HAVE_NOP_MCOUNT to be able to nop out
mcount call sites.  

TODO: Enable "objtool mcount" for clang LTO builds.

Sathvika Vasireddy (3):
  objtool: Move common code to utils.c
  objtool: Enable and implement 'mcount' subcommand
  objtool/mcount: Add powerpc specific functions

 Makefile                                      |   6 +
 arch/powerpc/Kconfig                          |   1 +
 arch/x86/Kconfig                              |   3 +-
 scripts/Makefile.build                        |  12 +
 tools/objtool/Build                           |   3 +
 tools/objtool/Makefile                        |   8 +-
 tools/objtool/arch/powerpc/Build              |   1 +
 tools/objtool/arch/powerpc/decode.c           |  51 +++++
 .../arch/powerpc/include/arch/cfi_regs.h      |  37 +++
 tools/objtool/arch/powerpc/include/arch/elf.h |   8 +
 tools/objtool/builtin-mcount.c                |  74 ++++++
 tools/objtool/check.c                         | 178 +--------------
 tools/objtool/include/objtool/builtin.h       |   4 +-
 tools/objtool/include/objtool/check.h         |   2 -
 tools/objtool/include/objtool/objtool.h       |   1 +
 tools/objtool/include/objtool/utils.h         |  28 +++
 tools/objtool/mcount.c                        | 138 ++++++++++++
 tools/objtool/objtool.c                       |   1 +
 tools/objtool/orc_gen.c                       |   1 +
 tools/objtool/utils.c                         | 210 ++++++++++++++++++
 tools/objtool/weak.c                          |   5 +
 21 files changed, 590 insertions(+), 182 deletions(-)
 create mode 100644 tools/objtool/arch/powerpc/Build
 create mode 100644 tools/objtool/arch/powerpc/decode.c
 create mode 100644 tools/objtool/arch/powerpc/include/arch/cfi_regs.h
 create mode 100644 tools/objtool/arch/powerpc/include/arch/elf.h
 create mode 100644 tools/objtool/builtin-mcount.c
 create mode 100644 tools/objtool/include/objtool/utils.h
 create mode 100644 tools/objtool/mcount.c
 create mode 100644 tools/objtool/utils.c

-- 
2.31.1