[PATCH v6 26/26] coresight: Add support for v8.4 SelfHosted tracing
From: Suzuki K Poulose <suzuki.poulose@arm.com>
Date: 2021-01-07 12:42:41
Also in:
lkml
Subsystem:
arm/coresight framework and drivers, hardware tracing facilities, the rest · Maintainers:
Suzuki K Poulose, Alexander Shishkin, Linus Torvalds
From: Jonathan Zhou <redacted> v8.4 tracing extensions added support for trace filtering controlled by TRFCR_ELx. This must be programmed to allow tracing at EL1/EL2 and EL0. The timestamp used is the virtual time. Also enable CONTEXIDR_EL2 tracing if we are running the kernel at EL2. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Mike Leach <redacted> Cc: Will Deacon <will@kernel.org> Signed-off-by: Jonathan Zhou <redacted> [ Move the trace filtering setup etm_init_arch_data() and clean ups] Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> --- .../coresight/coresight-etm4x-core.c | 25 +++++++++++++++++++ 1 file changed, 25 insertions(+)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 34a6cdff75e7..6d96f4226bca 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c@@ -859,6 +859,30 @@ static bool etm4_init_csdev_access(struct etmv4_drvdata *drvdata, return false; } +static void cpu_enable_tracing(void) +{ + u64 dfr0 = read_sysreg(id_aa64dfr0_el1); + u64 trfcr; + + if (!cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_TRACE_FILT_SHIFT)) + return; + + /* + * If the CPU supports v8.4 SelfHosted Tracing, enable + * tracing at the kernel EL and EL0, forcing to use the + * virtual time as the timestamp. + */ + trfcr = (TRFCR_ELx_TS_VIRTUAL | + TRFCR_ELx_ExTRE | + TRFCR_ELx_E0TRE); + + /* If we are running at EL2, allow tracing the CONTEXTIDR_EL2. */ + if (is_kernel_in_hyp_mode()) + trfcr |= TRFCR_EL2_CX; + + write_sysreg_s(trfcr, SYS_TRFCR_EL1); +} + static void etm4_init_arch_data(void *info) { u32 etmidr0;
@@ -1044,6 +1068,7 @@ static void etm4_init_arch_data(void *info) /* NUMCNTR, bits[30:28] number of counters available for tracing */ drvdata->nr_cntr = BMVAL(etmidr5, 28, 30); etm4_cs_lock(drvdata, csa); + cpu_enable_tracing(); } static inline u32 etm4_get_victlr_access_type(struct etmv4_config *config)
--
2.24.1
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