[PATCH 16/19] coresight: etm4x: Detect system instructions support
From: Suzuki K Poulose <suzuki.poulose@arm.com>
Date: 2020-09-11 08:45:27
Subsystem:
arm/coresight framework and drivers, hardware tracing facilities, the rest · Maintainers:
Suzuki K Poulose, Alexander Shishkin, Linus Torvalds
ETM v4.4 onwards adds support for system instruction access to the ETM. Detect the support on an ETM and switch to using the mode when available. Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> --- drivers/hwtracing/coresight/coresight-etm4x.c | 31 +++++++++++++++++++ 1 file changed, 31 insertions(+)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
index 0fce9fb12cff..dc5ac171db35 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x.c@@ -693,11 +693,39 @@ static void etm_detect_lock_status(struct etmv4_drvdata *drvdata, drvdata->os_lock_model = TRCOSLSR_OSM(os_lsr); } +static inline bool cpu_supports_sysreg_trace(void) +{ + u64 dfr0 = read_sysreg_s(SYS_ID_AA64DFR0_EL1); + + return ((dfr0 >> ID_AA64DFR0_TRACEVER_SHIFT) & 0xfUL) > 0; +} + static inline bool trace_unit_supported(u32 devarch) { return (devarch & ETM_DEVARCH_ID_MASK) == ETM_DEVARCH_ETMv4x_ARCH; } +static bool etm_init_sysreg_access(struct etmv4_drvdata *drvdata, + struct csdev_access *csa) +{ + u32 devarch; + + if (!cpu_supports_sysreg_trace()) + return false; + + devarch = read_etm4x_sysreg_const_offset(TRCDEVARCH); + if (!trace_unit_supported(devarch)) + return false; + *csa = (struct csdev_access) { + .io_mem = false, + .read = etm4x_sysreg_read, + .write = etm4x_sysreg_write, + }; + + drvdata->arch = devarch; + return true; +} + static bool etm_init_iomem_access(struct etmv4_drvdata *drvdata, struct csdev_access *csa) {
@@ -716,6 +744,9 @@ static bool etm_init_iomem_access(struct etmv4_drvdata *drvdata, static bool etm_init_csdev_access(struct etmv4_drvdata *drvdata, struct csdev_access *csa) { + if (etm_init_sysreg_access(drvdata, csa)) + return true; + if (drvdata->base) return etm_init_iomem_access(drvdata, csa);
--
2.24.1
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