[RFC PATCH 00/12] Add Linux RISC-V trace support via CoreSight
Zane Leung
liangzhen at linux.spacemit.com
Mon Apr 13 20:41:41 PDT 2026
From: liangzhen <zhen.liang at spacemit.com>
This series adds Linux RISC-V trace support via CoreSight, implementing RISC-V
trace drivers within the CoreSight framework and integrating them with perf tools.
The K3 SoC contains RISC-V Encoder, Funnel, ATB, CoreSight Funnel, and CoreSight TMC
components, which can be directly leveraged through the existing CoreSight infrastructure.
Linux RISC-V trace support form Anup Patel:
(https://patchwork.kernel.org/project/linux-riscv/cover/20260225062448.4027948-1-anup.patel@oss.qualcomm.com/)
which currently lacks ATB component support and guidance on reusing CoreSight components.
The series includes:
- RISC-V trace driver implementation within the CoreSight framework
- RISC-V Trace Encoder, Funnel, and ATB Bridge drivers as CoreSight devices
- RISC-V trace PMU record capabilities and parsing events in perf.
- RISC-V Nexus Trace decoder for perf tools
Any comments or suggestions are welcome.
Verification on K3 SoC:
To verify this patch series on K3 hardware, the following device tree are required:
1. RISC-V Trace Encoder node (8)
2. RISC-V ATB Bridge node (8)
3. RISC-V Trace Funnel node (2)
3. CoreSight Funnel configuration for RISC-V (1)
4. CoreSight TMC configuration for trace buffer (1)
/{
dummy_clk: apb-pclk {
compatible = "fixed-clock";
#clock-cells = <0x0>;
clock-output-names = "clk14mhz";
clock-frequency = <14000000>;
};
soc: soc {
#address-cells = <2>;
#size-cells = <2>;
encoder0: encoder at d9002000 {
compatible = "riscv,trace-encoder";
reg = <0x0 0xd9002000 0x0 0x1000>;
cpus = <&cpu_0>;
out-ports {
port {
cluster0_encoder0_out_port: endpoint {
remote-endpoint = <&cluster0_bridge0_in_port>;
};
};
};
};
bridge0: bridge at d9003000 {
compatible = "riscv,trace-atbbridge";
reg = <0x0 0xd9003000 0x0 0x1000>;
cpus = <&cpu_0>;
out-ports {
port {
cluster0_bridge0_out_port: endpoint {
remote-endpoint = <&cluster0_funnel_in_port0>;
};
};
};
in-ports {
port {
cluster0_bridge0_in_port: endpoint {
remote-endpoint = <&cluster0_encoder0_out_port>;
};
};
};
};
...
cluster0_funnel: funnel at d9000000 {
compatible = "riscv,trace-funnel";
reg = <0x0 0xd9000000 0x0 0x1000>;
cpus = <&cpu_0>, <&cpu_1>, <&cpu_2>, <&cpu_3>;
riscv,timestamp-present;
out-ports {
port {
cluster0_funnel_out_port: endpoint {
remote-endpoint = <&main_funnel_in_port0>;
};
};
};
in-ports {
#address-cells = <1>;
#size-cells = <0>;
port at 0 {
reg = <0>;
cluster0_funnel_in_port0: endpoint {
remote-endpoint = <&cluster0_bridge0_out_port>;
};
};
port at 1 {
reg = <1>;
cluster0_funnel_in_port1: endpoint {
remote-endpoint = <&cluster0_bridge1_out_port>;
};
};
port at 2 {
reg = <2>;
cluster0_funnel_in_port2: endpoint {
remote-endpoint = <&cluster0_bridge2_out_port>;
};
};
port at 3 {
reg = <3>;
cluster0_funnel_in_port3: endpoint {
remote-endpoint = <&cluster0_bridge3_out_port>;
};
};
};
};
cluster1_funnel: funnel at d9010000 {
compatible = "riscv,trace-funnel";
reg = <0x0 0xd9010000 0x0 0x1000>;
cpus = <&cpu_4>, <&cpu_5>, <&cpu_6>, <&cpu_7>;
riscv,timestamp-present;
out-ports {
port {
cluster1_funnel_out_port: endpoint {
remote-endpoint = <&main_funnel_in_port1>;
};
};
};
in-ports {
#address-cells = <1>;
#size-cells = <0>;
port at 0 {
reg = <0>;
cluster1_funnel_in_port0: endpoint {
remote-endpoint = <&cluster1_bridge0_out_port>;
};
};
port at 1 {
reg = <1>;
cluster1_funnel_in_port1: endpoint {
remote-endpoint = <&cluster1_bridge1_out_port>;
};
};
port at 2 {
reg = <2>;
cluster1_funnel_in_port2: endpoint {
remote-endpoint = <&cluster1_bridge2_out_port>;
};
};
port at 3 {
reg = <3>;
cluster1_funnel_in_port3: endpoint {
remote-endpoint = <&cluster1_bridge3_out_port>;
};
};
};
};
main_funnel: funnel at d9042000 {
compatible = "arm,coresight-dynamic-funnel", "arm,primecell";
reg = <0x0 0xd9042000 0x0 0x1000>;
clocks = <&dummy_clk>;
clock-names = "apb_pclk";
out-ports {
port {
main_funnel_out_port: endpoint {
remote-endpoint = <&etf_in_port>;
};
};
};
in-ports {
#address-cells = <1>;
#size-cells = <0>;
port at 0 {
reg = <0>;
main_funnel_in_port0: endpoint {
remote-endpoint = <&cluster0_funnel_out_port>;
};
};
port at 1 {
reg = <1>;
main_funnel_in_port1: endpoint {
remote-endpoint = <&cluster1_funnel_out_port>;
};
};
};
};
etf: etf at d9043000 {
compatible = "arm,coresight-tmc", "arm,primecell";
reg = <0x0 0xd9043000 0x0 0x1000>;
clocks = <&dummy_clk>;
clock-names = "apb_pclk";
out-ports {
port {
etf_out_port: endpoint {
remote-endpoint = <&etr_in_port>;
};
};
};
in-ports {
port {
etf_in_port: endpoint {
remote-endpoint = <&main_funnel_out_port>;
};
};
};
};
etr: etr at d9044000 {
compatible = "arm,coresight-tmc", "arm,primecell";
reg = <0x0 0xd9044000 0x0 0x1000>;
clocks = <&dummy_clk>;
clock-names = "apb_pclk";
arm,scatter-gather;
in-ports {
port {
etr_in_port: endpoint {
remote-endpoint = <&etf_out_port>;
};
};
};
};
};
};
Verification case:
~ # perf list pmu
rvtrace// [Kernel PMU event]
~ # perf record -e rvtrace/@tmc_etr0/ --per-thread uname
Linux
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.191 MB perf.data ]
~ # perf script
uname 137 [003] 1 branches: ffffffff80931470 rvtrace_poll_bit+0x38 ([kernel.kallsyms]) => ffffffff80931492 rvtrace_poll_bit+0x5a ([kernel.kallsyms])
uname 137 [003] 1 branches: ffffffff809328a6 encoder_enable_hw+0x252 ([kernel.kallsyms]) => ffffffff809328ba encoder_enable_hw+0x266 ([kernel.kallsyms])
uname 137 [003] 1 branches: ffffffff80932c4a encoder_enable+0x82 ([kernel.kallsyms]) => ffffffff80932c36 encoder_enable+0x6e ([kernel.kallsyms])
uname 137 [003] 1 branches: ffffffff80928198 etm_event_start+0xf0 ([kernel.kallsyms]) => ffffffff809281aa etm_event_start+0x102 ([kernel.kallsyms])
uname 137 [003] 1 branches: ffffffff809281e6 etm_event_start+0x13e ([kernel.kallsyms]) => ffffffff8092755e coresight_get_sink_id+0x16 ([kernel.kallsyms])
uname 137 [003] 1 branches: ffffffff8092820e etm_event_start+0x166 ([kernel.kallsyms]) => ffffffff80928226 etm_event_start+0x17e ([kernel.kallsyms])
uname 137 [003] 1 branches: ffffffff801c3bb4 perf_report_aux_output_id+0x0 ([kernel.kallsyms]) => ffffffff801c3bd6 perf_report_aux_output_id+0x22 ([kernel.kallsyms])
uname 137 [003] 1 branches: ffffffff801c3c5a perf_report_aux_output_id+0xa6 ([kernel.kallsyms]) => ffffffff801c3bf0 perf_report_aux_output_id+0x3c ([kernel.kallsyms])
uname 137 [003] 1 branches: ffffffff801c3c40 perf_report_aux_output_id+0x8c ([kernel.kallsyms]) => ffffffff801c3aea __perf_event_header__init_id+0x2a ([kernel.kallsyms])
uname 137 [003] 1 branches: ffffffff801c3b42 __perf_event_header__init_id+0x82 ([kernel.kallsyms]) => ffffffff801c3b4a __perf_event_header__init_id+0x8a ([kernel.kallsyms])
uname 137 [003] 1 branches: ffffffff801c3bb0 __perf_event_header__init_id+0xf0 ([kernel.kallsyms]) => ffffffff801c3b58 __perf_event_header__init_id+0x98 ([kernel.kallsyms])
uname 137 [003] 1 branches: ffffffff8004c658 __task_pid_nr_ns+0x0 ([kernel.kallsyms]) => ffffffff8004c696 __task_pid_nr_ns+0x3e ([kernel.kallsyms])
uname 137 [003] 1 branches: ffffffff8004c71e __task_pid_nr_ns+0xc6 ([kernel.kallsyms]) => ffffffff8004c6a4 __task_pid_nr_ns+0x4c ([kernel.kallsyms])
uname 137 [003] 1 branches: ffffffff8004c6e4 __task_pid_nr_ns+0x8c ([kernel.kallsyms]) => ffffffff8004c6e4 __task_pid_nr_ns+0x8c ([kernel.kallsyms])
...
liangzhen (12):
coresight: Add RISC-V support to CoreSight tracing
coresight: Initial implementation of RISC-V trace driver
coresight: Add RISC-V Trace Encoder driver
coresight: Add RISC-V Trace Funnel driver
coresight: Add RISC-V Trace ATB Bridge driver
coresight rvtrace: Add timestamp component support for encoder and
funnel
coresight: Add RISC-V PMU name support
perf tools: riscv: making rvtrace PMU listable
perf tools: Add RISC-V trace PMU record capabilities
perf tools: Add Nexus RISC-V Trace decoder
perf symbols: Add RISC-V PLT entry sizes
perf tools: Integrate RISC-V trace decoder into auxtrace
drivers/hwtracing/Kconfig | 2 +
drivers/hwtracing/coresight/Kconfig | 46 +-
drivers/hwtracing/coresight/Makefile | 6 +
drivers/hwtracing/coresight/coresight-core.c | 8 +
.../hwtracing/coresight/coresight-etm-perf.c | 1 -
.../hwtracing/coresight/coresight-etm-perf.h | 21 +
.../hwtracing/coresight/coresight-platform.c | 1 -
.../hwtracing/coresight/coresight-tmc-etf.c | 4 +
.../hwtracing/coresight/coresight-tmc-etr.c | 4 +
.../hwtracing/coresight/rvtrace-atbbridge.c | 239 +++
drivers/hwtracing/coresight/rvtrace-core.c | 135 ++
.../coresight/rvtrace-encoder-core.c | 562 +++++++
.../coresight/rvtrace-encoder-sysfs.c | 363 +++++
drivers/hwtracing/coresight/rvtrace-encoder.h | 151 ++
drivers/hwtracing/coresight/rvtrace-funnel.c | 337 ++++
drivers/hwtracing/coresight/rvtrace-funnel.h | 39 +
.../hwtracing/coresight/rvtrace-timestamp.c | 278 ++++
.../hwtracing/coresight/rvtrace-timestamp.h | 64 +
include/linux/coresight-pmu.h | 4 +
include/linux/rvtrace.h | 116 ++
tools/arch/riscv/include/asm/insn.h | 645 ++++++++
tools/perf/arch/riscv/util/Build | 2 +
tools/perf/arch/riscv/util/auxtrace.c | 490 ++++++
tools/perf/arch/riscv/util/pmu.c | 20 +
tools/perf/util/Build | 3 +
tools/perf/util/auxtrace.c | 4 +
tools/perf/util/auxtrace.h | 1 +
tools/perf/util/nexus-rv-decoder/Build | 1 +
.../util/nexus-rv-decoder/nexus-rv-decoder.c | 1364 +++++++++++++++++
.../util/nexus-rv-decoder/nexus-rv-decoder.h | 139 ++
.../perf/util/nexus-rv-decoder/nexus-rv-msg.h | 190 +++
tools/perf/util/rvtrace-decoder.c | 1039 +++++++++++++
tools/perf/util/rvtrace.h | 40 +
tools/perf/util/symbol-elf.c | 4 +
34 files changed, 6320 insertions(+), 3 deletions(-)
create mode 100644 drivers/hwtracing/coresight/rvtrace-atbbridge.c
create mode 100644 drivers/hwtracing/coresight/rvtrace-core.c
create mode 100644 drivers/hwtracing/coresight/rvtrace-encoder-core.c
create mode 100644 drivers/hwtracing/coresight/rvtrace-encoder-sysfs.c
create mode 100644 drivers/hwtracing/coresight/rvtrace-encoder.h
create mode 100644 drivers/hwtracing/coresight/rvtrace-funnel.c
create mode 100644 drivers/hwtracing/coresight/rvtrace-funnel.h
create mode 100644 drivers/hwtracing/coresight/rvtrace-timestamp.c
create mode 100644 drivers/hwtracing/coresight/rvtrace-timestamp.h
create mode 100644 include/linux/rvtrace.h
create mode 100644 tools/arch/riscv/include/asm/insn.h
create mode 100644 tools/perf/arch/riscv/util/auxtrace.c
create mode 100644 tools/perf/arch/riscv/util/pmu.c
create mode 100644 tools/perf/util/nexus-rv-decoder/Build
create mode 100644 tools/perf/util/nexus-rv-decoder/nexus-rv-decoder.c
create mode 100644 tools/perf/util/nexus-rv-decoder/nexus-rv-decoder.h
create mode 100644 tools/perf/util/nexus-rv-decoder/nexus-rv-msg.h
create mode 100644 tools/perf/util/rvtrace-decoder.c
create mode 100644 tools/perf/util/rvtrace.h
--
2.34.1
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