From 3f620f26576526ccc9e5cb1164bd1cf33a7c70bd Mon Sep 17 00:00:00 2001 From: James Clark Date: Wed, 14 Jan 2026 15:57:24 +0000 Subject: [PATCH] perf cs-etm: Don't use hard coded config bits when setting up TRCCONFIGR Perf only looks at attr.config when determining what was programmed into TRCCONFIGR. These bits could theoretically be in any of the config fields. Use the evsel__get_config_val() helper so it's agnostic to which config field they are in. The kernel will also stop publishing the TRCCONFIGR register bits in a header [1] so preempt that by defining them here. [1]: https://lore.kernel.org/linux-arm-kernel/20251128-james-cs-syncfreq-v8-10-4d319764cc58@linaro.org/ Reviewed-by: Ian Rogers Reviewed-by: Leo Yan Signed-off-by: James Clark Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: John Garry Cc: Leo Yan Cc: Mark Rutland Cc: Mike Leach Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Suzuki Poulouse Cc: Will Deacon Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/arch/arm/util/cs-etm.c | 79 +++++++++++++------------------ 1 file changed, 34 insertions(+), 45 deletions(-) diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c index f535027ce862..12b28562c2f3 100644 --- a/tools/perf/arch/arm/util/cs-etm.c +++ b/tools/perf/arch/arm/util/cs-etm.c @@ -68,6 +68,14 @@ static const char * const metadata_ete_ro[] = { enum cs_etm_version { CS_NOT_PRESENT, CS_ETMV3, CS_ETMV4, CS_ETE }; +/* ETMv4 CONFIGR register bits */ +#define TRCCONFIGR_BB BIT(3) +#define TRCCONFIGR_CCI BIT(4) +#define TRCCONFIGR_CID BIT(6) +#define TRCCONFIGR_VMID BIT(7) +#define TRCCONFIGR_TS BIT(11) +#define TRCCONFIGR_RS BIT(12) +#define TRCCONFIGR_VMIDOPT BIT(15) /* ETMv3 ETMCR register bits */ #define ETMCR_CYC_ACC BIT(12) @@ -517,56 +525,37 @@ static u64 cs_etm_synth_etmcr(struct auxtrace_record *itr) return etmcr; } -static u64 cs_etm_get_config(struct auxtrace_record *itr) +static u64 cs_etmv4_synth_trcconfigr(struct auxtrace_record *itr) { + u64 trcconfigr = 0; struct cs_etm_recording *ptr = - container_of(itr, struct cs_etm_recording, itr); + container_of(itr, struct cs_etm_recording, itr); struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu; - struct evlist *evlist = ptr->evlist; - struct evsel *evsel = cs_etm_get_evsel(evlist, cs_etm_pmu); - - /* - * Variable perf_event_attr::config is assigned to - * ETMv3/PTM. The bit fields have been made to match - * the ETMv3.5 ETRMCR register specification. See the - * PMU_FORMAT_ATTR() declarations in - * drivers/hwtracing/coresight/coresight-perf.c for - * details. - */ - return evsel ? evsel->core.attr.config : 0; -} - -#ifndef BIT -#define BIT(N) (1UL << (N)) -#endif + struct evsel *evsel = cs_etm_get_evsel(ptr->evlist, cs_etm_pmu); + u64 val; -static u64 cs_etmv4_get_config(struct auxtrace_record *itr) -{ - u64 config = 0; - u64 config_opts = 0; + if (!evsel) + return 0; /* - * The perf event variable config bits represent both - * the command line options and register programming - * bits in ETMv3/PTM. For ETMv4 we must remap options - * to real bits + * Synthesize what the kernel programmed into TRCCONFIGR based on + * what options the event was opened with. This doesn't have to be + * complete or 100% accurate, not all bits used by OpenCSD anyway. */ - config_opts = cs_etm_get_config(itr); - if (config_opts & BIT(ETM_OPT_CYCACC)) - config |= BIT(ETM4_CFG_BIT_CYCACC); - if (config_opts & BIT(ETM_OPT_CTXTID)) - config |= BIT(ETM4_CFG_BIT_CTXTID); - if (config_opts & BIT(ETM_OPT_TS)) - config |= BIT(ETM4_CFG_BIT_TS); - if (config_opts & BIT(ETM_OPT_RETSTK)) - config |= BIT(ETM4_CFG_BIT_RETSTK); - if (config_opts & BIT(ETM_OPT_CTXTID2)) - config |= BIT(ETM4_CFG_BIT_VMID) | - BIT(ETM4_CFG_BIT_VMID_OPT); - if (config_opts & BIT(ETM_OPT_BRANCH_BROADCAST)) - config |= BIT(ETM4_CFG_BIT_BB); - - return config; + if (!evsel__get_config_val(evsel, "cycacc", &val) && val) + trcconfigr |= TRCCONFIGR_CCI; + if (!evsel__get_config_val(evsel, "contextid1", &val) && val) + trcconfigr |= TRCCONFIGR_CID; + if (!evsel__get_config_val(evsel, "timestamp", &val) && val) + trcconfigr |= TRCCONFIGR_TS; + if (!evsel__get_config_val(evsel, "retstack", &val) && val) + trcconfigr |= TRCCONFIGR_RS; + if (!evsel__get_config_val(evsel, "contextid2", &val) && val) + trcconfigr |= TRCCONFIGR_VMID | TRCCONFIGR_VMIDOPT; + if (!evsel__get_config_val(evsel, "branch_broadcast", &val) && val) + trcconfigr |= TRCCONFIGR_BB; + + return trcconfigr; } static size_t @@ -688,7 +677,7 @@ static void cs_etm_save_etmv4_header(__u64 data[], struct auxtrace_record *itr, struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu; /* Get trace configuration register */ - data[CS_ETMV4_TRCCONFIGR] = cs_etmv4_get_config(itr); + data[CS_ETMV4_TRCCONFIGR] = cs_etmv4_synth_trcconfigr(itr); /* traceID set to legacy version, in case new perf running on older system */ data[CS_ETMV4_TRCTRACEIDR] = cs_etm_get_legacy_trace_id(cpu); @@ -720,7 +709,7 @@ static void cs_etm_save_ete_header(__u64 data[], struct auxtrace_record *itr, st struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu; /* Get trace configuration register */ - data[CS_ETE_TRCCONFIGR] = cs_etmv4_get_config(itr); + data[CS_ETE_TRCCONFIGR] = cs_etmv4_synth_trcconfigr(itr); /* traceID set to legacy version, in case new perf running on older system */ data[CS_ETE_TRCTRACEIDR] = cs_etm_get_legacy_trace_id(cpu); -- 2.47.3