Hi Suzuki,
On Thu, Jan 07, 2021 at 12:38:33PM +0000, Suzuki K Poulose wrote:
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.
I have queued your work in my local tree. I will have a final pass before pushing to coresight-next tomorrow or on Monday.
Thanks, Mathieu
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-v6
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 (24): 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: Add commentary on the registers coresight: etm4x: Add sysreg access helpers 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 | 46 +- drivers/hwtracing/coresight/coresight-etm4x.h | 498 ++++++++++- .../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 | 225 ++++- 19 files changed, 1423 insertions(+), 431 deletions(-)
-- 2.24.1