[PATCH 00/11] Linux RISC-V trace framework and drivers

From: Anup Patel <apatel@ventanamicro.com>
To: Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Greg KH <gregkh@linuxfoundation.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
	devicetree@vger.kernel.org, Alexandre Ghiti <alex@ghiti.fr>,
	Atish Patra <atish.patra@linux.dev>,
	Peter Zijlstra <peterz@infradead.org>,
	Anup Patel <anup@brainfault.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
	Jiri Olsa <jolsa@kernel.org>,
	Anup Patel <apatel@ventanamicro.com>,
	Mayuresh Chitale <mchitale@gmail.com>,
	Namhyung Kim <namhyung@kernel.org>,
	linux-riscv@lists.infradead.org,
	Andrew Jones <ajones@ventanamicro.com>,
	Liang Kan <kan.liang@linux.intel.com>
Subject: [PATCH 00/11] Linux RISC-V trace framework and drivers
Date: Thu,  2 Oct 2025 11:37:21 +0530	[thread overview]
Message-ID: <20251002060732.100213-1-apatel@ventanamicro.com> (raw)

This series adds initial support for RISC-V trace framework and drivers.
The RISC-V trace v1.0 specification is already ratified and can be found at:
https://github.com/riscv-non-isa/e-trace-encap/releases/tag/v1.0.0-ratified
https://github.com/riscv-non-isa/tg-nexus-trace/releases/tag/1.0_Ratified

The RISC-V trace framework and drivers are designed to be agnostic to the
underlying trace protocol hence both RISC-V E-trace and RISC-V N-trace should
work fine. The discovery of trace protocl parameters are left to user-space
trace decoder.

In ther future, there will be subsequent series adding:
1) Sysfs support
2) ACPI support
3) More trace drivers (such as funnel, ATB, etc)
4) Support for upcoming self-hosted trace specification
5) ... and more ...

These patches can also be found in the riscv_trace_support_v1 branch at:
https://github.com/avpatel/linux.git

To test the patches, we need QEMU virt machine with RISC-V trace support
which can be found in rv-etrace branch at:
https://gitlab.com/danielhb/qemu.git

To capture rvtrace data using perf on QEMU virt machine do the following:
1) Launch QEMU virt machine
   $ qemu-system-riscv64 -nographic -M virt -smp 2 -bios fw_dynamic.bin \
     -kernel Image -append "root=/dev/vda rw console=ttyS0 earlycon=sbi" \
     -drive file=/path/to/rootfs.img,id=disk1,if=none,format=raw \
     -device virtio-blk-device,drive=disk1
2) Run perf record to capture rvtrace data
   $ perf record --all-cpus -e rvtrace/event=0x1/ <command>
3) The step2 would create a perf.data file which has the rvtrace data.
   Now run perf report -D and look for PERF_RECORD_AUXTRACE event
   section(s) which point(s) to the actual rvtrace data offset.

Anup Patel (5):
  dt-bindings: Add RISC-V trace component bindings
  rvtrace: Initial implementation of driver framework
  rvtrace: Add functions to create/destroy a trace component path
  rvtrace: Add function to copy into perf AUX buffer
  MAINTAINERS: Add entry for RISC-V trace framework and drivers

Mayuresh Chitale (6):
  rvtrace: Add functions to start/stop tracing on a component path
  rvtrace: Add trace encoder driver
  rvtrace: Add trace ramsink driver
  rvtrace: Add perf driver for tracing using perf tool
  perf tools: Add RISC-V trace PMU record capabilities
  perf tools: Initial support for RISC-V trace decoder

 .../bindings/riscv/riscv,trace-component.yaml | 110 +++
 MAINTAINERS                                   |  11 +
 drivers/Makefile                              |   1 +
 drivers/hwtracing/Kconfig                     |   2 +
 drivers/hwtracing/rvtrace/Kconfig             |  32 +
 drivers/hwtracing/rvtrace/Makefile            |   6 +
 drivers/hwtracing/rvtrace/rvtrace-core.c      | 781 ++++++++++++++++++
 drivers/hwtracing/rvtrace/rvtrace-encoder.c   | 107 +++
 drivers/hwtracing/rvtrace/rvtrace-perf.c      | 343 ++++++++
 drivers/hwtracing/rvtrace/rvtrace-platform.c  | 174 ++++
 drivers/hwtracing/rvtrace/rvtrace-ramsink.c   | 198 +++++
 include/linux/rvtrace.h                       | 341 ++++++++
 tools/perf/arch/riscv/util/Build              |   1 +
 tools/perf/arch/riscv/util/auxtrace.c         | 218 +++++
 tools/perf/util/Build                         |   1 +
 tools/perf/util/auxtrace.c                    |   4 +
 tools/perf/util/auxtrace.h                    |   1 +
 tools/perf/util/rvtrace-decoder.c             |  91 ++
 tools/perf/util/rvtrace.h                     |  20 +
 19 files changed, 2442 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/riscv/riscv,trace-component.yaml
 create mode 100644 drivers/hwtracing/rvtrace/Kconfig
 create mode 100644 drivers/hwtracing/rvtrace/Makefile
 create mode 100644 drivers/hwtracing/rvtrace/rvtrace-core.c
 create mode 100644 drivers/hwtracing/rvtrace/rvtrace-encoder.c
 create mode 100644 drivers/hwtracing/rvtrace/rvtrace-perf.c
 create mode 100644 drivers/hwtracing/rvtrace/rvtrace-platform.c
 create mode 100644 drivers/hwtracing/rvtrace/rvtrace-ramsink.c
 create mode 100644 include/linux/rvtrace.h
 create mode 100644 tools/perf/arch/riscv/util/auxtrace.c
 create mode 100644 tools/perf/util/rvtrace-decoder.c
 create mode 100644 tools/perf/util/rvtrace.h

-- 
2.43.0

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