hw-breakpoints: new hardware breakpoints API

Hi Ingo,

The new hardware breakpoint API has benefit from deep reviews since
its first iteration several months ago, and Prasad has addressed
most (all?) of them.

After a small reorg and few fixes that were done recently, it seems
ready for integration on -tip.

I've tested it successfully for both kernel (ftrace) and user (gdb)
hardware breakpoints.

Thanks!

Frederic.

The following changes since commit 43bd1236234cacbc18d1476a9b57e7a306efddf5:
  Frederic Weisbecker (1):
        tracing/stat: remove unappropriate safe walk on list

are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing.git hw-breakpoints

K.Prasad (12):
      hw-breakpoints: prepare the code for Hardware Breakpoint interfaces
      hw-breakpoints: introducing generic hardware breakpoint handler interfaces
      hw-breakpoints: x86 architecture implementation of Hardware Breakpoint interfaces
      hw-breakpoints: modifying generic debug exception to use thread-specific debug registers
      hw-breakpoints: use wrapper routines around debug registers in processor related functions
      hw-breakpoints: use the new wrapper routines to access debug registers in process/thread code
      hw-breakpoints: modify signal handling code to refrain from re-enabling HW Breakpoints
      hw-breakpoints: modify Ptrace routines to access breakpoint registers
      hw-breakpoints: cleanup HW Breakpoint registers before kexec
      hw-breakpoints: sample HW breakpoint over kernel data address
      hw-breakpoints: ftrace plugin for kernel symbol tracing using HW Breakpoint interfaces
      hw-breakpoints: reset bits in dr6 after the corresponding exception is handled

 arch/Kconfig                            |    4 +
 arch/x86/Kconfig                        |    1 +
 arch/x86/include/asm/a.out-core.h       |    8 +-
 arch/x86/include/asm/debugreg.h         |   29 ++
 arch/x86/include/asm/hw_breakpoint.h    |   55 ++++
 arch/x86/include/asm/processor.h        |    8 +-
 arch/x86/kernel/Makefile                |    2 +-
 arch/x86/kernel/hw_breakpoint.c         |  391 +++++++++++++++++++++++
 arch/x86/kernel/kgdb.c                  |    6 +
 arch/x86/kernel/kprobes.c               |    9 +-
 arch/x86/kernel/machine_kexec_32.c      |    2 +
 arch/x86/kernel/machine_kexec_64.c      |    2 +
 arch/x86/kernel/process.c               |   22 +-
 arch/x86/kernel/process_32.c            |   28 ++
 arch/x86/kernel/process_64.c            |   31 ++
 arch/x86/kernel/ptrace.c                |  231 +++++++++------
 arch/x86/kernel/signal.c                |    9 -
 arch/x86/kernel/smpboot.c               |    3 +
 arch/x86/kernel/traps.c                 |   71 ++---
 arch/x86/mm/kmmio.c                     |    8 +-
 arch/x86/power/cpu_32.c                 |   13 +-
 arch/x86/power/cpu_64.c                 |   12 +-
 include/asm-generic/hw_breakpoint.h     |  139 ++++++++
 kernel/Makefile                         |    1 +
 kernel/hw_breakpoint.c                  |  378 ++++++++++++++++++++++
 kernel/trace/Kconfig                    |   21 ++
 kernel/trace/Makefile                   |    1 +
 kernel/trace/trace.h                    |   23 ++
 kernel/trace/trace_ksym.c               |  525 +++++++++++++++++++++++++++++++
 kernel/trace/trace_selftest.c           |   53 +++
 samples/Kconfig                         |    6 +
 samples/Makefile                        |    3 +-
 samples/hw_breakpoint/Makefile          |    1 +
 samples/hw_breakpoint/data_breakpoint.c |   83 +++++
 34 files changed, 1987 insertions(+), 192 deletions(-)
 create mode 100644 arch/x86/include/asm/hw_breakpoint.h
 create mode 100644 arch/x86/kernel/hw_breakpoint.c
 create mode 100644 include/asm-generic/hw_breakpoint.h
 create mode 100644 kernel/hw_breakpoint.c
 create mode 100644 kernel/trace/trace_ksym.c
 create mode 100644 samples/hw_breakpoint/Makefile
 create mode 100644 samples/hw_breakpoint/data_breakpoint.c