perf/x86/intel: Add Branch Monitoring support

This patchset adds support for Intel's branch monitoring feature. This
feature uses heuristics to detect the occurrence of an ROP(Return Oriented
Programming) or ROP like(JOP: Jump oriented programming) attack. These
heuristics are based off certain performance monitoring statistics,
measured dynamically over a short configurable window period. ROP is a
malware trend in which the attacker can compromise a return pointer held
on the stack to redirect execution to a different desired instruction.

Currently, only the Cannonlake family of Intel processors support this
feature. This feature is enabled by CONFIG_PERF_EVENTS_INTEL_BM.

Once the kernel is compiled with CONFIG_PERF_EVENTS_INTEL_BM=y on a
Cannonlake system, the following perf events are added which can be viewed
with perf list:
  intel_bm/branch-misp/                              [Kernel PMU event]
  intel_bm/call-ret/                                 [Kernel PMU event]
  intel_bm/far-branch/                               [Kernel PMU event]
  intel_bm/indirect-branch-misp/                     [Kernel PMU event]
  intel_bm/ret-misp/                                 [Kernel PMU event]
  intel_bm/rets/                                     [Kernel PMU event]

A perf-based kernel driver has been used to monitor the occurrence of
one of the 6 branch monitoring events. There are 2 counters that each
can select between one of these events for evaluation over a specified
instruction window size (0 to 1023). For each counter, a threshold value
(0 to 127) can be configured to set a point at which an interrupt is
generated. The entire system can monitor a maximum of 2 events(either
from the same or different tasks) at any given time.

Apart from the kernel driver, this patchset adds CPUID of Cannonlake
processors to Intel family list and the Documentation/x86/intel_bm.txt
file with some information about Intel Branch monitoring.

Megha Dey (3):
  x86/cpu/intel: Add Cannonlake to Intel family
  perf/x86/intel/bm.c: Add Intel Branch Monitoring support
  x86, bm: Add documentation on Intel Branch Monitoring

 Documentation/x86/intel_bm.txt      | 216 ++++++++++++
 arch/x86/events/Kconfig             |  10 +
 arch/x86/events/intel/Makefile      |   2 +
 arch/x86/events/intel/bm.c          | 635 ++++++++++++++++++++++++++++++++++++
 arch/x86/include/asm/intel-family.h |   2 +
 arch/x86/include/asm/msr-index.h    |   5 +
 include/linux/perf_event.h          |   8 +-
 kernel/events/core.c                |   8 +
 8 files changed, 885 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/x86/intel_bm.txt
 create mode 100644 arch/x86/events/intel/bm.c

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1.9.1