[PATCH v2] Coresight: etm4x: add support for Self-hosted trace

[Jonathan Zhou]

ARMv8.4 architecture extension introduces ARMv8.4-Trace, Armv8.4
Self-hosted Trace Extensions. It provides control of exception
levels and security states. Let's add this feature detection and
enable E1TRE and E0TRE in TRFCR_EL1 if Self-hosted Trace is
supported.

Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Will Deacon <will at kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose at arm.com>
Cc: Shaokun Zhang <zhangshaokun at hisilicon.com>
Signed-off-by: Jonathan Zhou <jonathan.zhouwen at huawei.com>
---
 arch/arm64/include/asm/sysreg.h               |  8 ++++++++
 drivers/hwtracing/coresight/coresight-etm4x.c | 23 +++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 554a7e8ecb07..53da5f326667 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -184,6 +184,13 @@
 
 #define SYS_ZCR_EL1			sys_reg(3, 0, 1, 2, 0)
 
+/* Trace Filter control */
+#define SYS_TRFCR_EL1			sys_reg(3, 0, 1, 2, 1)
+/* Trace is allowed at EL0 */
+#define SYS_TRFCR_EL1_E0TRE		BIT(0)
+/* Trace is allowed at EL1 */
+#define SYS_TRFCR_EL1_E1TRE		BIT(1)
+
 #define SYS_TTBR0_EL1			sys_reg(3, 0, 2, 0, 0)
 #define SYS_TTBR1_EL1			sys_reg(3, 0, 2, 0, 1)
 #define SYS_TCR_EL1			sys_reg(3, 0, 2, 0, 2)
@@ -772,6 +779,7 @@
 #define ID_AA64MMFR2_CNP_SHIFT		0
 
 /* id_aa64dfr0 */
+#define ID_AA64DFR0_SELF_HOSTED_SHIFT	40
 #define ID_AA64DFR0_DOUBLELOCK_SHIFT	36
 #define ID_AA64DFR0_PMSVER_SHIFT	32
 #define ID_AA64DFR0_CTX_CMPS_SHIFT	28
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
index 96425e818fc2..f72b457c2bad 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x.c
@@ -28,6 +28,7 @@
 #include <linux/perf_event.h>
 #include <linux/pm_runtime.h>
 #include <linux/property.h>
+#include <asm/sysreg.h>
 #include <asm/sections.h>
 #include <asm/local.h>
 #include <asm/virt.h>
@@ -785,6 +786,24 @@ static void etm4_init_arch_data(void *info)
 	CS_LOCK(drvdata->base);
 }
 
+static void etm4_init_sysctrl(void *info)
+{
+	u64 sys_trfcr_el1, dfr0;
+	int trace_filt;
+
+	dfr0 = read_sysreg(id_aa64dfr0_el1);
+
+	trace_filt = cpuid_feature_extract_unsigned_field(dfr0,
+					ID_AA64DFR0_SELF_HOSTED_SHIFT);
+	/* if selfhosted trace implemented, enable trace EL0 as default. */
+	if (trace_filt == 0x1) {
+		sys_trfcr_el1 = read_sysreg_s(SYS_TRFCR_EL1);
+		write_sysreg_s(sys_trfcr_el1 | SYS_TRFCR_EL1_E0TRE,
+				SYS_TRFCR_EL1);
+		isb();
+	}
+}
+
 static void etm4_set_default_config(struct etmv4_config *config)
 {
 	/* disable all events tracing */
@@ -1504,6 +1523,10 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id)
 				etm4_init_arch_data,  drvdata, 1))
 		dev_err(dev, "ETM arch init failed\n");
 
+	if (smp_call_function_single(drvdata->cpu,
+				etm4_init_sysctrl, drvdata, 1))
+		dev_err(dev, "ETM sysctrl init failed\n");
+
 	ret = etm4_pm_setup_cpuslocked();
 	cpus_read_unlock();
 
-- 
1.9.1