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    Subject[PATCH v7 00/28] coresight: etm4x: Support for system instructions
    Date
    CoreSight ETMv4.4 obsoletes memory mapped access to ETM and
    mandates the system instructions for registers.
    This also implies that they may not be on the amba bus.
    Right now all the CoreSight components are accessed via memory
    map. Also, we have some common routines in coresight generic
    code driver (e.g, CS_LOCK, claim/disclaim), which assume the
    mmio. In order to preserve the generic algorithms at a single
    place and to allow dynamic switch for ETMs, this series introduces
    an abstraction layer for accessing a coresight device. It is
    designed such that the mmio access are fast tracked (i.e, without
    an indirect function call).

    This will also help us to get rid of the driver+attribute specific
    sysfs show/store routines and replace them with a single routine
    to access a given register offset (which can be embedded in the
    dev_ext_attribute). This is not currently implemented in the series,
    but can be achieved.

    Further we switch the generic routines to work with the abstraction.
    With this in place, we refactor the etm4x code a bit to allow for
    supporting the system instructions with very little new code.

    We use TRCDEVARCH for the detection of the ETM component, which
    is a standard register as per CoreSight architecture, rather than
    the etm specific id register TRCIDR1. This is for making sure
    that we are able to detect the ETM via system instructions accurately,
    when the the trace unit could be anything (etm or a custom trace unit).
    To keep the backward compatibility for any existing broken
    impelementation which may not implement TRCDEVARCH, we fall back to TRCIDR1.
    Also this covers us for the changes in the future architecture [0].

    Also, v8.4 self-hosted tracing extensions (coupled with ETMv4.4) adds
    new filtering registers for trace by exception level. So on a v8.4
    system, with Trace Filtering support, without the appropriate
    programming of the Trace filter registers (TRFCR_ELx), tracing
    will not be enabled. This series also includes the TraceFiltering
    support to cover the ETM-v4.4 support.

    The series has been mildly tested on a model for system instructions.
    I would really appreciate any testing on real hardware.

    Applies on coresight/next. A tree is available here [1].

    [0] https://developer.arm.com/docs/ddi0601/g/aarch64-system-registers/trcidr1
    [1] https://gitlab.arm.com/linux-arm/linux-skp coresight/etm/sysreg-v7

    Changes since v6:
    - New patch: Patch9 : Prepare the sysfs attributes for
    filtering by offset of the register
    - New patch: Patch12: Hide ETM registers unaccessible
    on the ETM (for system instructions based ETMs)
    - Split the list of ETM registers to memory mapped only
    and common registers (Patch 11)
    - Fixed the alignment issues pointed by Mathieu
    (Patch 3, 14, 24)

    Changes since v5:
    - Rebased on to coresight/next.
    - Moved trcdevarch to mgmt/ in sysfs and updated the sysfs ABI
    document (Mike Leach)
    - New patch : Moved the etm4_check_arch_features to run on the CPU, since
    the PID of the ETM has to be read on the CPU and is unavailable
    otherwise.

    Changes since v4:
    - Fix typo in commit description for the patches 02 & 15
    - Refactor the AMBA device "remove" call back for use with
    paltform_driver. (patch 21). Thus remove Review tag by Mathieu,
    even though the changes are minimal.
    - Added "remove" callback for platform_driver in patch 22, removed
    Review tag by Mathieu
    - Add 'U' suffix for constants in Patch 24 (Catalin)
    - Fixed field extraction in Patch 25

    Changes since v3:
    - Device tree compatible changed to etm4x
    - Use etm4x_** instead of generalizing etm_ in etm4x driver.
    - Added v8.4 self hosted trace support patches, reworked
    from Jonathan's series.
    - Dropped queued patches.
    - Expose TRCDEVARCH via trcidr, as this will be needed for
    the userspace tools to determine the trace major/minor
    arch versions.
    - Remove csa argument to read()/write() (Mathieu)
    - Fix secure exception mask calculation (Mathieu)
    - Fix various coding style comments (Mathieu)
    (See individual patches for change log)

    Changes since V2:
    - Several fixes to the ETM register accesses. Access a register
    when it is present.
    - Add support for TRCIDR3.NUMPROCS for v4.2+
    - Drop OS lock detection. Use software lock only in case of mmio.
    - Fix issues with the Exception level masks (Mike Leach)
    - Fall back to using TRCIDR1 when TRCDEVARCH is not "present"
    - Use a generic notion of ETM architecture (rather than using
    the encoding as in registers)
    - Fixed some checkpatch issues.
    - Changed the dts compatible string to "arm,coresight-etm-sysreg"
    (Mike Leach)

    Changes since V1:
    - Flip the switch for iomem from no_iomem to io_mem in csdev_access.
    - Split patches for claim/disclaim and CS_LOCK/UNLOCK conversions.
    - Move device access initialisation for etm4x to the target CPU
    - Cleanup secure exception level mask handling.
    - Switch to use TRCDEVARCH for ETM component discovery. This
    is for making
    - Check the availability of OS/Software Locks before using them.

    Known issues:
    Checkpatch failure for "coresight: etm4x: Add sysreg access helpers" :

    ERROR: Macros with complex values should be enclosed in parentheses
    #121: FILE: drivers/hwtracing/coresight/coresight-etm4x.h:153:
    +#define CASE_READ(res, x) \
    + case (x): { (res) = read_etm4x_sysreg_const_offset((x)); break; }

    I don't know a way to fix the warning without loosing the code
    readability, which I believe is crucial for such a construct.



    Jonathan Zhou (2):
    arm64: Add TRFCR_ELx definitions
    coresight: Add support for v8.4 SelfHosted tracing

    Suzuki K Poulose (26):
    coresight: etm4x: Handle access to TRCSSPCICRn
    coresight: etm4x: Skip accessing TRCPDCR in save/restore
    coresight: Introduce device access abstraction
    coresight: tpiu: Prepare for using coresight device access abstraction
    coresight: Convert coresight_timeout to use access abstraction
    coresight: Convert claim/disclaim operations to use access wrappers
    coresight: etm4x: Always read the registers on the host CPU
    coresight: etm4x: Convert all register accesses
    coresight: etm4x: Make offset available for sysfs attributes
    coresight: etm4x: Add commentary on the registers
    coresight: etm4x: Add sysreg access helpers
    coresight: etm4x: Hide sysfs attributes for unavailable registers
    coresight: etm4x: Define DEVARCH register fields
    coresight: etm4x: Check for Software Lock
    coresight: etm4x: Cleanup secure exception level masks
    coresight: etm4x: Clean up exception level masks
    coresight: etm4x: Handle ETM architecture version
    coresight: etm4x: Detect access early on the target CPU
    coresight: etm4x: Use TRCDEVARCH for component discovery
    coresight: etm4x: Expose trcdevarch via sysfs
    coresight: etm4x: Add necessary synchronization for sysreg access
    coresight: etm4x: Detect system instructions support
    coresight: etm4x: Refactor probing routine
    coresight: etm4x: Run arch feature detection on the CPU
    coresight: etm4x: Add support for sysreg only devices
    dts: bindings: coresight: ETM system register access only units

    .../testing/sysfs-bus-coresight-devices-etm4x | 8 +
    .../devicetree/bindings/arm/coresight.txt | 5 +-
    arch/arm64/include/asm/sysreg.h | 11 +
    drivers/hwtracing/coresight/coresight-catu.c | 12 +-
    drivers/hwtracing/coresight/coresight-core.c | 122 ++-
    .../hwtracing/coresight/coresight-cti-core.c | 18 +-
    drivers/hwtracing/coresight/coresight-etb10.c | 10 +-
    .../coresight/coresight-etm3x-core.c | 9 +-
    .../coresight/coresight-etm4x-core.c | 805 ++++++++++++------
    .../coresight/coresight-etm4x-sysfs.c | 187 ++--
    drivers/hwtracing/coresight/coresight-etm4x.h | 505 ++++++++++-
    .../hwtracing/coresight/coresight-funnel.c | 7 +-
    .../coresight/coresight-replicator.c | 13 +-
    drivers/hwtracing/coresight/coresight-stm.c | 4 +-
    .../hwtracing/coresight/coresight-tmc-core.c | 16 +-
    .../hwtracing/coresight/coresight-tmc-etf.c | 10 +-
    .../hwtracing/coresight/coresight-tmc-etr.c | 4 +-
    drivers/hwtracing/coresight/coresight-tpiu.c | 31 +-
    include/linux/coresight.h | 220 ++++-
    19 files changed, 1520 insertions(+), 477 deletions(-)

    --
    2.24.1

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