[PATCH V2 0/9] Add support for configure and control of Hardware Trace Macro(HTM)

[Athira Rajeev]

H_HTM (Hardware Trace Macro) hypervisor call is an HCALL to export
data from Hardware Trace Macro (HTM) function. The debugfs interface
to export the HTM function data in a partition currently supports only
dumping of HTM data in an lpar. Patchset add support for configuration
and control of HTM function via debugfs interface.

With the patchset, after loading htmdump module,
below files are present:

ls /sys/kernel/debug/powerpc/htmdump/
  coreindexonchip  htmcaps  htmconfigure  htmflags  htminfo  htmsetup
  htmstart  htmstatus  htmtype  nodalchipindex  nodeindex  trace

- nodeindex, nodalchipindex, coreindexonchip specifies which
  partition to configure the HTM for.
- htmtype: specifies the type of HTM. Supported target is
  hardwareTarget.
- trace: is to read the HTM data.
- htmconfigure: Configure/Deconfigure the HTM. Writing 1 to
  the file will configure the trace, writing 0 to the file
  will do deconfigure.
- htmstart: start/Stop the HTM. Writing 1 to the file will
  start the tracing, writing 0 to the file will stop the tracing.
- htmstatus: get the status of HTM. This is needed to understand
  the HTM state after each operation.
- htmsetup: set the HTM buffer size. Size of HTM buffer is in
  power of 2.
- htminfo: provides the system processor configuration details.
  This is needed to understand the appropriate values for nodeindex,
  nodalchipindex, coreindexonchip.
- htmcaps : provides the HTM capabilities like minimum/maximum buffer
  size, what kind of tracing the HTM supports etc.
- htmflags : allows to pass flags to hcall. Currently supports
  controlling the wrapping of HTM buffer.

Example usage:
To collect HTM traces for a partition represented by nodeindex as
zero, nodalchipindex as 1 and coreindexonchip as 12.

  # cd /sys/kernel/debug/powerpc/htmdump/
  # echo 2 > htmtype
  # echo 0 > nodeindex
  # echo 1 > nodalchipindex
  # echo 12 > coreindexonchip
  # echo 1 > htmflags     # to set noWrap for HTM buffers
  # echo 1 > htmconfigure # Configure the HTM
  # echo 1 > htmstart     # Start the HTM
  # echo 0 > htmstart     # Stop the HTM
  # echo 0 > htmconfigure # Deconfigure the HTM
  # cat htmstatus         # Dump the status of HTM entries as data

Changelog:
V2: Venkat reported that patch 7 failed to apply on powerpc-next.
Fixed that in V2.

Athira Rajeev (9):
  powerpc/pseries/htmdump: Add htm_hcall_wrapper to integrate other htm
    operations
  powerpc/pseries/htmdump: Add htm configure support to htmdump module
  powerpc/pseries/htmdump: Add htm start support to htmdump module
  powerpc/pseries/htmdump: Add htm status support to htmdump module
  powerpc/pseries/htmdump: Add htm info support to htmdump module
  powerpc/pseries/htmdump: Add htm setup support to htmdump module
  powerpc/pseries/htmdump: Add htm flags support to htmdump module
  powerpc/pseries/htmdump: Add htm capabilities support to htmdump
    module
  powerpc/pseries/htmdump: Add documentation for H_HTM debugfs interface

 Documentation/arch/powerpc/htm.rst        | 104 ++++++
 arch/powerpc/include/asm/plpar_wrappers.h |  20 +-
 arch/powerpc/platforms/pseries/htmdump.c  | 370 +++++++++++++++++++++-
 3 files changed, 475 insertions(+), 19 deletions(-)
 create mode 100644 Documentation/arch/powerpc/htm.rst

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2.43.5