Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm updates from Paolo Bonzini:
 "This is a large update by KVM standards, including AMD PSP (Platform
  Security Processor, aka "AMD Secure Technology") and ARM CoreSight
  (debug and trace) changes.

  ARM:

   - CoreSight: Add support for ETE and TRBE

   - Stage-2 isolation for the host kernel when running in protected
     mode

   - Guest SVE support when running in nVHE mode

   - Force W^X hypervisor mappings in nVHE mode

   - ITS save/restore for guests using direct injection with GICv4.1

   - nVHE panics now produce readable backtraces

   - Guest support for PTP using the ptp_kvm driver

   - Performance improvements in the S2 fault handler

  x86:

   - AMD PSP driver changes

   - Optimizations and cleanup of nested SVM code

   - AMD: Support for virtual SPEC_CTRL

   - Optimizations of the new MMU code: fast invalidation, zap under
     read lock, enable/disably dirty page logging under read lock

   - /dev/kvm API for AMD SEV live migration (guest API coming soon)

   - support SEV virtual machines sharing the same encryption context

   - support SGX in virtual machines

   - add a few more statistics

   - improved directed yield heuristics

   - Lots and lots of cleanups

  Generic:

   - Rework of MMU notifier interface, simplifying and optimizing the
     architecture-specific code

   - a handful of "Get rid of oprofile leftovers" patches

   - Some selftests improvements"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (379 commits)
  KVM: selftests: Speed up set_memory_region_test
  selftests: kvm: Fix the check of return value
  KVM: x86: Take advantage of kvm_arch_dy_has_pending_interrupt()
  KVM: SVM: Skip SEV cache flush if no ASIDs have been used
  KVM: SVM: Remove an unnecessary prototype declaration of sev_flush_asids()
  KVM: SVM: Drop redundant svm_sev_enabled() helper
  KVM: SVM: Move SEV VMCB tracking allocation to sev.c
  KVM: SVM: Explicitly check max SEV ASID during sev_hardware_setup()
  KVM: SVM: Unconditionally invoke sev_hardware_teardown()
  KVM: SVM: Enable SEV/SEV-ES functionality by default (when supported)
  KVM: SVM: Condition sev_enabled and sev_es_enabled on CONFIG_KVM_AMD_SEV=y
  KVM: SVM: Append "_enabled" to module-scoped SEV/SEV-ES control variables
  KVM: SEV: Mask CPUID[0x8000001F].eax according to supported features
  KVM: SVM: Move SEV module params/variables to sev.c
  KVM: SVM: Disable SEV/SEV-ES if NPT is disabled
  KVM: SVM: Free sev_asid_bitmap during init if SEV setup fails
  KVM: SVM: Zero out the VMCB array used to track SEV ASID association
  x86/sev: Drop redundant and potentially misleading 'sev_enabled'
  KVM: x86: Move reverse CPUID helpers to separate header file
  KVM: x86: Rename GPR accessors to make mode-aware variants the defaults
  ...

11 files changed, 1698 insertions, 56 deletions

diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
index 7b44ba22cbe1..84530fd80998 100644
--- a/drivers/hwtracing/coresight/Kconfig
+++ b/drivers/hwtracing/coresight/Kconfig
@@ -97,15 +97,15 @@ config CORESIGHT_SOURCE_ETM3X
 	  module will be called coresight-etm3x.
 
 config CORESIGHT_SOURCE_ETM4X
-	tristate "CoreSight Embedded Trace Macrocell 4.x driver"
+	tristate "CoreSight ETMv4.x / ETE driver"
 	depends on ARM64
 	select CORESIGHT_LINKS_AND_SINKS
 	select PID_IN_CONTEXTIDR
 	help
-	  This driver provides support for the ETM4.x tracer module, tracing the
-	  instructions that a processor is executing. This is primarily useful
-	  for instruction level tracing. Depending on the implemented version
-	  data tracing may also be available.
+	  This driver provides support for the CoreSight Embedded Trace Macrocell
+	  version 4.x and the Embedded Trace Extensions (ETE). Both are CPU tracer
+	  modules, tracing the instructions that a processor is executing. This is
+	  primarily useful for instruction level tracing.
 
 	  To compile this driver as a module, choose M here: the
 	  module will be called coresight-etm4x.
@@ -173,4 +173,18 @@ config CORESIGHT_CTI_INTEGRATION_REGS
 	  CTI trigger connections between this and other devices.These
 	  registers are not used in normal operation and can leave devices in
 	  an inconsistent state.
+
+config CORESIGHT_TRBE
+	tristate "Trace Buffer Extension (TRBE) driver"
+	depends on ARM64 && CORESIGHT_SOURCE_ETM4X
+	help
+	  This driver provides support for percpu Trace Buffer Extension (TRBE).
+	  TRBE always needs to be used along with it's corresponding percpu ETE
+	  component. ETE generates trace data which is then captured with TRBE.
+	  Unlike traditional sink devices, TRBE is a CPU feature accessible via
+	  system registers. But it's explicit dependency with trace unit (ETE)
+	  requires it to be plugged in as a coresight sink device.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called coresight-trbe.
 endif
diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile
index f20e357758d1..d60816509755 100644
--- a/drivers/hwtracing/coresight/Makefile
+++ b/drivers/hwtracing/coresight/Makefile
@@ -21,5 +21,6 @@ obj-$(CONFIG_CORESIGHT_STM) += coresight-stm.o
 obj-$(CONFIG_CORESIGHT_CPU_DEBUG) += coresight-cpu-debug.o
 obj-$(CONFIG_CORESIGHT_CATU) += coresight-catu.o
 obj-$(CONFIG_CORESIGHT_CTI) += coresight-cti.o
+obj-$(CONFIG_CORESIGHT_TRBE) += coresight-trbe.o
 coresight-cti-y := coresight-cti-core.o	coresight-cti-platform.o \
 		   coresight-cti-sysfs.o
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index b57bea167102..6c68d34d956e 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -23,6 +23,7 @@
 #include "coresight-priv.h"
 
 static DEFINE_MUTEX(coresight_mutex);
+static DEFINE_PER_CPU(struct coresight_device *, csdev_sink);
 
 /**
  * struct coresight_node - elements of a path, from source to sink
@@ -70,6 +71,18 @@ void coresight_remove_cti_ops(void)
 }
 EXPORT_SYMBOL_GPL(coresight_remove_cti_ops);
 
+void coresight_set_percpu_sink(int cpu, struct coresight_device *csdev)
+{
+	per_cpu(csdev_sink, cpu) = csdev;
+}
+EXPORT_SYMBOL_GPL(coresight_set_percpu_sink);
+
+struct coresight_device *coresight_get_percpu_sink(int cpu)
+{
+	return per_cpu(csdev_sink, cpu);
+}
+EXPORT_SYMBOL_GPL(coresight_get_percpu_sink);
+
 static int coresight_id_match(struct device *dev, void *data)
 {
 	int trace_id, i_trace_id;
@@ -784,6 +797,14 @@ static int _coresight_build_path(struct coresight_device *csdev,
 	if (csdev == sink)
 		goto out;
 
+	if (coresight_is_percpu_source(csdev) && coresight_is_percpu_sink(sink) &&
+	    sink == per_cpu(csdev_sink, source_ops(csdev)->cpu_id(csdev))) {
+		if (_coresight_build_path(sink, sink, path) == 0) {
+			found = true;
+			goto out;
+		}
+	}
+
 	/* Not a sink - recursively explore each port found on this element */
 	for (i = 0; i < csdev->pdata->nr_outport; i++) {
 		struct coresight_device *child_dev;
@@ -999,8 +1020,12 @@ coresight_find_default_sink(struct coresight_device *csdev)
 	int depth = 0;
 
 	/* look for a default sink if we have not found for this device */
-	if (!csdev->def_sink)
-		csdev->def_sink = coresight_find_sink(csdev, &depth);
+	if (!csdev->def_sink) {
+		if (coresight_is_percpu_source(csdev))
+			csdev->def_sink = per_cpu(csdev_sink, source_ops(csdev)->cpu_id(csdev));
+		if (!csdev->def_sink)
+			csdev->def_sink = coresight_find_sink(csdev, &depth);
+	}
 	return csdev->def_sink;
 }
 
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index c1bec2ad3911..6f398377fec9 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -24,7 +24,26 @@
 static struct pmu etm_pmu;
 static bool etm_perf_up;
 
-static DEFINE_PER_CPU(struct perf_output_handle, ctx_handle);
+/*
+ * An ETM context for a running event includes the perf aux handle
+ * and aux_data. For ETM, the aux_data (etm_event_data), consists of
+ * the trace path and the sink configuration. The event data is accessible
+ * via perf_get_aux(handle). However, a sink could "end" a perf output
+ * handle via the IRQ handler. And if the "sink" encounters a failure
+ * to "begin" another session (e.g due to lack of space in the buffer),
+ * the handle will be cleared. Thus, the event_data may not be accessible
+ * from the handle when we get to the etm_event_stop(), which is required
+ * for stopping the trace path. The event_data is guaranteed to stay alive
+ * until "free_aux()", which cannot happen as long as the event is active on
+ * the ETM. Thus the event_data for the session must be part of the ETM context
+ * to make sure we can disable the trace path.
+ */
+struct etm_ctxt {
+	struct perf_output_handle handle;
+	struct etm_event_data *event_data;
+};
+
+static DEFINE_PER_CPU(struct etm_ctxt, etm_ctxt);
 static DEFINE_PER_CPU(struct coresight_device *, csdev_src);
 
 /*
@@ -232,6 +251,25 @@ static void etm_free_aux(void *data)
 	schedule_work(&event_data->work);
 }
 
+/*
+ * Check if two given sinks are compatible with each other,
+ * so that they can use the same sink buffers, when an event
+ * moves around.
+ */
+static bool sinks_compatible(struct coresight_device *a,
+			     struct coresight_device *b)
+{
+	if (!a || !b)
+		return false;
+	/*
+	 * If the sinks are of the same subtype and driven
+	 * by the same driver, we can use the same buffer
+	 * on these sinks.
+	 */
+	return (a->subtype.sink_subtype == b->subtype.sink_subtype) &&
+	       (sink_ops(a) == sink_ops(b));
+}
+
 static void *etm_setup_aux(struct perf_event *event, void **pages,
 			   int nr_pages, bool overwrite)
 {
@@ -239,6 +277,7 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
 	int cpu = event->cpu;
 	cpumask_t *mask;
 	struct coresight_device *sink = NULL;
+	struct coresight_device *user_sink = NULL, *last_sink = NULL;
 	struct etm_event_data *event_data = NULL;
 
 	event_data = alloc_event_data(cpu);
@@ -249,7 +288,7 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
 	/* First get the selected sink from user space. */
 	if (event->attr.config2) {
 		id = (u32)event->attr.config2;
-		sink = coresight_get_sink_by_id(id);
+		sink = user_sink = coresight_get_sink_by_id(id);
 	}
 
 	mask = &event_data->mask;
@@ -277,14 +316,33 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
 		}
 
 		/*
-		 * No sink provided - look for a default sink for one of the
-		 * devices. At present we only support topology where all CPUs
-		 * use the same sink [N:1], so only need to find one sink. The
-		 * coresight_build_path later will remove any CPU that does not
-		 * attach to the sink, or if we have not found a sink.
+		 * No sink provided - look for a default sink for all the ETMs,
+		 * where this event can be scheduled.
+		 * We allocate the sink specific buffers only once for this
+		 * event. If the ETMs have different default sink devices, we
+		 * can only use a single "type" of sink as the event can carry
+		 * only one sink specific buffer. Thus we have to make sure
+		 * that the sinks are of the same type and driven by the same
+		 * driver, as the one we allocate the buffer for. As such
+		 * we choose the first sink and check if the remaining ETMs
+		 * have a compatible default sink. We don't trace on a CPU
+		 * if the sink is not compatible.
 		 */
-		if (!sink)
+		if (!user_sink) {
+			/* Find the default sink for this ETM */
 			sink = coresight_find_default_sink(csdev);
+			if (!sink) {
+				cpumask_clear_cpu(cpu, mask);
+				continue;
+			}
+
+			/* Check if this sink compatible with the last sink */
+			if (last_sink && !sinks_compatible(last_sink, sink)) {
+				cpumask_clear_cpu(cpu, mask);
+				continue;
+			}
+			last_sink = sink;
+		}
 
 		/*
 		 * Building a path doesn't enable it, it simply builds a
@@ -312,7 +370,12 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
 	if (!sink_ops(sink)->alloc_buffer || !sink_ops(sink)->free_buffer)
 		goto err;
 
-	/* Allocate the sink buffer for this session */
+	/*
+	 * Allocate the sink buffer for this session. All the sinks
+	 * where this event can be scheduled are ensured to be of the
+	 * same type. Thus the same sink configuration is used by the
+	 * sinks.
+	 */
 	event_data->snk_config =
 			sink_ops(sink)->alloc_buffer(sink, event, pages,
 						     nr_pages, overwrite);
@@ -332,13 +395,18 @@ static void etm_event_start(struct perf_event *event, int flags)
 {
 	int cpu = smp_processor_id();
 	struct etm_event_data *event_data;
-	struct perf_output_handle *handle = this_cpu_ptr(&ctx_handle);
+	struct etm_ctxt *ctxt = this_cpu_ptr(&etm_ctxt);
+	struct perf_output_handle *handle = &ctxt->handle;
 	struct coresight_device *sink, *csdev = per_cpu(csdev_src, cpu);
 	struct list_head *path;
 
 	if (!csdev)
 		goto fail;
 
+	/* Have we messed up our tracking ? */
+	if (WARN_ON(ctxt->event_data))
+		goto fail;
+
 	/*
 	 * Deal with the ring buffer API and get a handle on the
 	 * session's information.
@@ -374,6 +442,8 @@ static void etm_event_start(struct perf_event *event, int flags)
 	if (source_ops(csdev)->enable(csdev, event, CS_MODE_PERF))
 		goto fail_disable_path;
 
+	/* Save the event_data for this ETM */
+	ctxt->event_data = event_data;
 out:
 	return;
 
@@ -392,13 +462,30 @@ static void etm_event_stop(struct perf_event *event, int mode)
 	int cpu = smp_processor_id();
 	unsigned long size;
 	struct coresight_device *sink, *csdev = per_cpu(csdev_src, cpu);
-	struct perf_output_handle *handle = this_cpu_ptr(&ctx_handle);
-	struct etm_event_data *event_data = perf_get_aux(handle);
+	struct etm_ctxt *ctxt = this_cpu_ptr(&etm_ctxt);
+	struct perf_output_handle *handle = &ctxt->handle;
+	struct etm_event_data *event_data;
 	struct list_head *path;
 
+	/*
+	 * If we still have access to the event_data via handle,
+	 * confirm that we haven't messed up the tracking.
+	 */
+	if (handle->event &&
+	    WARN_ON(perf_get_aux(handle) != ctxt->event_data))
+		return;
+
+	event_data = ctxt->event_data;
+	/* Clear the event_data as this ETM is stopping the trace. */
+	ctxt->event_data = NULL;
+
 	if (event->hw.state == PERF_HES_STOPPED)
 		return;
 
+	/* We must have a valid event_data for a running event */
+	if (WARN_ON(!event_data))
+		return;
+
 	if (!csdev)
 		return;
 
@@ -416,7 +503,13 @@ static void etm_event_stop(struct perf_event *event, int mode)
 	/* tell the core */
 	event->hw.state = PERF_HES_STOPPED;
 
-	if (mode & PERF_EF_UPDATE) {
+	/*
+	 * If the handle is not bound to an event anymore
+	 * (e.g, the sink driver was unable to restart the
+	 * handle due to lack of buffer space), we don't
+	 * have to do anything here.
+	 */
+	if (handle->event && (mode & PERF_EF_UPDATE)) {
 		if (WARN_ON_ONCE(handle->event != event))
 			return;
 
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index a5b13a7779c3..db881993c211 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -31,6 +31,7 @@
 #include <linux/pm_runtime.h>
 #include <linux/property.h>
 
+#include <asm/barrier.h>
 #include <asm/sections.h>
 #include <asm/sysreg.h>
 #include <asm/local.h>
@@ -114,30 +115,91 @@ void etm4x_sysreg_write(u64 val, u32 offset, bool _relaxed, bool _64bit)
 	}
 }
 
-static void etm4_os_unlock_csa(struct etmv4_drvdata *drvdata, struct csdev_access *csa)
+static u64 ete_sysreg_read(u32 offset, bool _relaxed, bool _64bit)
 {
-	/* Writing 0 to TRCOSLAR unlocks the trace registers */
-	etm4x_relaxed_write32(csa, 0x0, TRCOSLAR);
-	drvdata->os_unlock = true;
+	u64 res = 0;
+
+	switch (offset) {
+	ETE_READ_CASES(res)
+	default :
+		pr_warn_ratelimited("ete: trying to read unsupported register @%x\n",
+				    offset);
+	}
+
+	if (!_relaxed)
+		__iormb(res);	/* Imitate the !relaxed I/O helpers */
+
+	return res;
+}
+
+static void ete_sysreg_write(u64 val, u32 offset, bool _relaxed, bool _64bit)
+{
+	if (!_relaxed)
+		__iowmb();	/* Imitate the !relaxed I/O helpers */
+	if (!_64bit)
+		val &= GENMASK(31, 0);
+
+	switch (offset) {
+	ETE_WRITE_CASES(val)
+	default :
+		pr_warn_ratelimited("ete: trying to write to unsupported register @%x\n",
+				    offset);
+	}
+}
+
+static void etm_detect_os_lock(struct etmv4_drvdata *drvdata,
+			       struct csdev_access *csa)
+{
+	u32 oslsr = etm4x_relaxed_read32(csa, TRCOSLSR);
+
+	drvdata->os_lock_model = ETM_OSLSR_OSLM(oslsr);
+}
+
+static void etm_write_os_lock(struct etmv4_drvdata *drvdata,
+			      struct csdev_access *csa, u32 val)
+{
+	val = !!val;
+
+	switch (drvdata->os_lock_model) {
+	case ETM_OSLOCK_PRESENT:
+		etm4x_relaxed_write32(csa, val, TRCOSLAR);
+		break;
+	case ETM_OSLOCK_PE:
+		write_sysreg_s(val, SYS_OSLAR_EL1);
+		break;
+	default:
+		pr_warn_once("CPU%d: Unsupported Trace OSLock model: %x\n",
+			     smp_processor_id(), drvdata->os_lock_model);
+		fallthrough;
+	case ETM_OSLOCK_NI:
+		return;
+	}
 	isb();
 }
 
+static inline void etm4_os_unlock_csa(struct etmv4_drvdata *drvdata,
+				      struct csdev_access *csa)
+{
+	WARN_ON(drvdata->cpu != smp_processor_id());
+
+	/* Writing 0 to OS Lock unlocks the trace unit registers */
+	etm_write_os_lock(drvdata, csa, 0x0);
+	drvdata->os_unlock = true;
+}
+
 static void etm4_os_unlock(struct etmv4_drvdata *drvdata)
 {
 	if (!WARN_ON(!drvdata->csdev))
 		etm4_os_unlock_csa(drvdata, &drvdata->csdev->access);
-
 }
 
 static void etm4_os_lock(struct etmv4_drvdata *drvdata)
 {
 	if (WARN_ON(!drvdata->csdev))
 		return;
-
-	/* Writing 0x1 to TRCOSLAR locks the trace registers */
-	etm4x_relaxed_write32(&drvdata->csdev->access, 0x1, TRCOSLAR);
+	/* Writing 0x1 to OS Lock locks the trace registers */
+	etm_write_os_lock(drvdata, &drvdata->csdev->access, 0x1);
 	drvdata->os_unlock = false;
-	isb();
 }
 
 static void etm4_cs_lock(struct etmv4_drvdata *drvdata,
@@ -371,6 +433,13 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
 		etm4x_relaxed_write32(csa, trcpdcr | TRCPDCR_PU, TRCPDCR);
 	}
 
+	/*
+	 * ETE mandates that the TRCRSR is written to before
+	 * enabling it.
+	 */
+	if (etm4x_is_ete(drvdata))
+		etm4x_relaxed_write32(csa, TRCRSR_TA, TRCRSR);
+
 	/* Enable the trace unit */
 	etm4x_relaxed_write32(csa, 1, TRCPRGCTLR);
 
@@ -654,6 +723,7 @@ static int etm4_enable(struct coresight_device *csdev,
 static void etm4_disable_hw(void *info)
 {
 	u32 control;
+	u64 trfcr;
 	struct etmv4_drvdata *drvdata = info;
 	struct etmv4_config *config = &drvdata->config;
 	struct coresight_device *csdev = drvdata->csdev;
@@ -677,18 +747,32 @@ static void etm4_disable_hw(void *info)
 	control &= ~0x1;
 
 	/*
+	 * If the CPU supports v8.4 Trace filter Control,
+	 * set the ETM to trace prohibited region.
+	 */
+	if (drvdata->trfc) {
+		trfcr = read_sysreg_s(SYS_TRFCR_EL1);
+		write_sysreg_s(trfcr & ~(TRFCR_ELx_ExTRE | TRFCR_ELx_E0TRE),
+			       SYS_TRFCR_EL1);
+		isb();
+	}
+	/*
 	 * Make sure everything completes before disabling, as recommended
 	 * by section 7.3.77 ("TRCVICTLR, ViewInst Main Control Register,
 	 * SSTATUS") of ARM IHI 0064D
 	 */
 	dsb(sy);
 	isb();
+	/* Trace synchronization barrier, is a nop if not supported */
+	tsb_csync();
 	etm4x_relaxed_write32(csa, control, TRCPRGCTLR);
 
 	/* wait for TRCSTATR.PMSTABLE to go to '1' */
 	if (coresight_timeout(csa, TRCSTATR, TRCSTATR_PMSTABLE_BIT, 1))
 		dev_err(etm_dev,
 			"timeout while waiting for PM stable Trace Status\n");
+	if (drvdata->trfc)
+		write_sysreg_s(trfcr, SYS_TRFCR_EL1);
 
 	/* read the status of the single shot comparators */
 	for (i = 0; i < drvdata->nr_ss_cmp; i++) {
@@ -817,13 +901,24 @@ static bool etm4_init_sysreg_access(struct etmv4_drvdata *drvdata,
 	 * ETMs implementing sysreg access must implement TRCDEVARCH.
 	 */
 	devarch = read_etm4x_sysreg_const_offset(TRCDEVARCH);
-	if ((devarch & ETM_DEVARCH_ID_MASK) != ETM_DEVARCH_ETMv4x_ARCH)
+	switch (devarch & ETM_DEVARCH_ID_MASK) {
+	case ETM_DEVARCH_ETMv4x_ARCH:
+		*csa = (struct csdev_access) {
+			.io_mem	= false,
+			.read	= etm4x_sysreg_read,
+			.write	= etm4x_sysreg_write,
+		};
+		break;
+	case ETM_DEVARCH_ETE_ARCH:
+		*csa = (struct csdev_access) {
+			.io_mem	= false,
+			.read	= ete_sysreg_read,
+			.write	= ete_sysreg_write,
+		};
+		break;
+	default:
 		return false;
-	*csa = (struct csdev_access) {
-		.io_mem	= false,
-		.read	= etm4x_sysreg_read,
-		.write	= etm4x_sysreg_write,
-	};
+	}
 
 	drvdata->arch = etm_devarch_to_arch(devarch);
 	return true;
@@ -873,7 +968,7 @@ static bool etm4_init_csdev_access(struct etmv4_drvdata *drvdata,
 	return false;
 }
 
-static void cpu_enable_tracing(void)
+static void cpu_enable_tracing(struct etmv4_drvdata *drvdata)
 {
 	u64 dfr0 = read_sysreg(id_aa64dfr0_el1);
 	u64 trfcr;
@@ -881,6 +976,7 @@ static void cpu_enable_tracing(void)
 	if (!cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_TRACE_FILT_SHIFT))
 		return;
 
+	drvdata->trfc = true;
 	/*
 	 * If the CPU supports v8.4 SelfHosted Tracing, enable
 	 * tracing at the kernel EL and EL0, forcing to use the
@@ -920,6 +1016,9 @@ static void etm4_init_arch_data(void *info)
 	if (!etm4_init_csdev_access(drvdata, csa))
 		return;
 
+	/* Detect the support for OS Lock before we actually use it */
+	etm_detect_os_lock(drvdata, csa);
+
 	/* Make sure all registers are accessible */
 	etm4_os_unlock_csa(drvdata, csa);
 	etm4_cs_unlock(drvdata, csa);
@@ -1082,7 +1181,7 @@ 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();
+	cpu_enable_tracing(drvdata);
 }
 
 static inline u32 etm4_get_victlr_access_type(struct etmv4_config *config)
@@ -1760,6 +1859,8 @@ static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid)
 	struct etmv4_drvdata *drvdata;
 	struct coresight_desc desc = { 0 };
 	struct etm4_init_arg init_arg = { 0 };
+	u8 major, minor;
+	char *type_name;
 
 	drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
 	if (!drvdata)
@@ -1786,10 +1887,6 @@ static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid)
 	if (drvdata->cpu < 0)
 		return drvdata->cpu;
 
-	desc.name = devm_kasprintf(dev, GFP_KERNEL, "etm%d", drvdata->cpu);
-	if (!desc.name)
-		return -ENOMEM;
-
 	init_arg.drvdata = drvdata;
 	init_arg.csa = &desc.access;
 	init_arg.pid = etm_pid;
@@ -1806,6 +1903,22 @@ static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid)
 	    fwnode_property_present(dev_fwnode(dev), "qcom,skip-power-up"))
 		drvdata->skip_power_up = true;
 
+	major = ETM_ARCH_MAJOR_VERSION(drvdata->arch);
+	minor = ETM_ARCH_MINOR_VERSION(drvdata->arch);
+
+	if (etm4x_is_ete(drvdata)) {
+		type_name = "ete";
+		/* ETE v1 has major version == 0b101. Adjust this for logging.*/
+		major -= 4;
+	} else {
+		type_name = "etm";
+	}
+
+	desc.name = devm_kasprintf(dev, GFP_KERNEL,
+				   "%s%d", type_name, drvdata->cpu);
+	if (!desc.name)
+		return -ENOMEM;
+
 	etm4_init_trace_id(drvdata);
 	etm4_set_default(&drvdata->config);
 
@@ -1833,9 +1946,8 @@ static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid)
 
 	etmdrvdata[drvdata->cpu] = drvdata;
 
-	dev_info(&drvdata->csdev->dev, "CPU%d: ETM v%d.%d initialized\n",
-		 drvdata->cpu, ETM_ARCH_MAJOR_VERSION(drvdata->arch),
-		 ETM_ARCH_MINOR_VERSION(drvdata->arch));
+	dev_info(&drvdata->csdev->dev, "CPU%d: %s v%d.%d initialized\n",
+		 drvdata->cpu, type_name, major, minor);
 
 	if (boot_enable) {
 		coresight_enable(drvdata->csdev);
@@ -1979,6 +2091,7 @@ static struct amba_driver etm4x_amba_driver = {
 
 static const struct of_device_id etm4_sysreg_match[] = {
 	{ .compatible	= "arm,coresight-etm4x-sysreg" },
+	{ .compatible	= "arm,embedded-trace-extension" },
 	{}
 };
 
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
index 0995a10790f4..007bad9e7ad8 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
@@ -2374,12 +2374,20 @@ static inline bool
 etm4x_register_implemented(struct etmv4_drvdata *drvdata, u32 offset)
 {
 	switch (offset) {
-	ETM4x_SYSREG_LIST_CASES
+	ETM_COMMON_SYSREG_LIST_CASES
 		/*
-		 * Registers accessible via system instructions are always
-		 * implemented.
+		 * Common registers to ETE & ETM4x accessible via system
+		 * instructions are always implemented.
 		 */
 		return true;
+
+	ETM4x_ONLY_SYSREG_LIST_CASES
+		/*
+		 * We only support etm4x and ete. So if the device is not
+		 * ETE, it must be ETMv4x.
+		 */
+		return !etm4x_is_ete(drvdata);
+
 	ETM4x_MMAP_LIST_CASES
 		/*
 		 * Registers accessible only via memory-mapped registers
@@ -2389,8 +2397,13 @@ etm4x_register_implemented(struct etmv4_drvdata *drvdata, u32 offset)
 		 * coresight_register() and the csdev is not initialized
 		 * until that is done. So rely on the drvdata->base to
 		 * detect if we have a memory mapped access.
+		 * Also ETE doesn't implement memory mapped access, thus
+		 * it is sufficient to check that we are using mmio.
 		 */
 		return !!drvdata->base;
+
+	ETE_ONLY_SYSREG_LIST_CASES
+		return etm4x_is_ete(drvdata);
 	}
 
 	return false;
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
index 0af60571aa23..e5b79bdb9851 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.h
+++ b/drivers/hwtracing/coresight/coresight-etm4x.h
@@ -29,6 +29,7 @@
 #define TRCAUXCTLR			0x018
 #define TRCEVENTCTL0R			0x020
 #define TRCEVENTCTL1R			0x024
+#define TRCRSR				0x028
 #define TRCSTALLCTLR			0x02C
 #define TRCTSCTLR			0x030
 #define TRCSYNCPR			0x034
@@ -49,6 +50,7 @@
 #define TRCSEQRSTEVR			0x118
 #define TRCSEQSTR			0x11C
 #define TRCEXTINSELR			0x120
+#define TRCEXTINSELRn(n)		(0x120 + (n * 4)) /* n = 0-3 */
 #define TRCCNTRLDVRn(n)			(0x140 + (n * 4)) /* n = 0-3 */
 #define TRCCNTCTLRn(n)			(0x150 + (n * 4)) /* n = 0-3 */
 #define TRCCNTVRn(n)			(0x160 + (n * 4)) /* n = 0-3 */
@@ -126,6 +128,8 @@
 #define TRCCIDR2			0xFF8
 #define TRCCIDR3			0xFFC
 
+#define TRCRSR_TA			BIT(12)
+
 /*
  * System instructions to access ETM registers.
  * See ETMv4.4 spec ARM IHI0064F section 4.3.6 System instructions
@@ -160,10 +164,22 @@
 #define CASE_NOP(__unused, x)					\
 	case (x):	/* fall through */
 
+#define ETE_ONLY_SYSREG_LIST(op, val)		\
+	CASE_##op((val), TRCRSR)		\
+	CASE_##op((val), TRCEXTINSELRn(1))	\
+	CASE_##op((val), TRCEXTINSELRn(2))	\
+	CASE_##op((val), TRCEXTINSELRn(3))
+
 /* List of registers accessible via System instructions */
-#define ETM_SYSREG_LIST(op, val)		\
-	CASE_##op((val), TRCPRGCTLR)		\
+#define ETM4x_ONLY_SYSREG_LIST(op, val)		\
 	CASE_##op((val), TRCPROCSELR)		\
+	CASE_##op((val), TRCVDCTLR)		\
+	CASE_##op((val), TRCVDSACCTLR)		\
+	CASE_##op((val), TRCVDARCCTLR)		\
+	CASE_##op((val), TRCOSLAR)
+
+#define ETM_COMMON_SYSREG_LIST(op, val)		\
+	CASE_##op((val), TRCPRGCTLR)		\
 	CASE_##op((val), TRCSTATR)		\
 	CASE_##op((val), TRCCONFIGR)		\
 	CASE_##op((val), TRCAUXCTLR)		\
@@ -180,9 +196,6 @@
 	CASE_##op((val), TRCVIIECTLR)		\
 	CASE_##op((val), TRCVISSCTLR)		\
 	CASE_##op((val), TRCVIPCSSCTLR)		\
-	CASE_##op((val), TRCVDCTLR)		\
-	CASE_##op((val), TRCVDSACCTLR)		\
-	CASE_##op((val), TRCVDARCCTLR)		\
 	CASE_##op((val), TRCSEQEVRn(0))		\
 	CASE_##op((val), TRCSEQEVRn(1))		\
 	CASE_##op((val), TRCSEQEVRn(2))		\
@@ -277,7 +290,6 @@
 	CASE_##op((val), TRCSSPCICRn(5))	\
 	CASE_##op((val), TRCSSPCICRn(6))	\
 	CASE_##op((val), TRCSSPCICRn(7))	\
-	CASE_##op((val), TRCOSLAR)		\
 	CASE_##op((val), TRCOSLSR)		\
 	CASE_##op((val), TRCACVRn(0))		\
 	CASE_##op((val), TRCACVRn(1))		\
@@ -369,12 +381,38 @@
 	CASE_##op((val), TRCPIDR2)		\
 	CASE_##op((val), TRCPIDR3)
 
-#define ETM4x_READ_SYSREG_CASES(res)	ETM_SYSREG_LIST(READ, (res))
-#define ETM4x_WRITE_SYSREG_CASES(val)	ETM_SYSREG_LIST(WRITE, (val))
+#define ETM4x_READ_SYSREG_CASES(res)		\
+	ETM_COMMON_SYSREG_LIST(READ, (res))	\
+	ETM4x_ONLY_SYSREG_LIST(READ, (res))
+
+#define ETM4x_WRITE_SYSREG_CASES(val)		\
+	ETM_COMMON_SYSREG_LIST(WRITE, (val))	\
+	ETM4x_ONLY_SYSREG_LIST(WRITE, (val))
+
+#define ETM_COMMON_SYSREG_LIST_CASES		\
+	ETM_COMMON_SYSREG_LIST(NOP, __unused)
+
+#define ETM4x_ONLY_SYSREG_LIST_CASES		\
+	ETM4x_ONLY_SYSREG_LIST(NOP, __unused)
+
+#define ETM4x_SYSREG_LIST_CASES			\
+	ETM_COMMON_SYSREG_LIST_CASES		\
+	ETM4x_ONLY_SYSREG_LIST(NOP, __unused)
 
-#define ETM4x_SYSREG_LIST_CASES		ETM_SYSREG_LIST(NOP, __unused)
 #define ETM4x_MMAP_LIST_CASES		ETM_MMAP_LIST(NOP, __unused)
 
+/* ETE only supports system register access */
+#define ETE_READ_CASES(res)			\
+	ETM_COMMON_SYSREG_LIST(READ, (res))	\
+	ETE_ONLY_SYSREG_LIST(READ, (res))
+
+#define ETE_WRITE_CASES(val)			\
+	ETM_COMMON_SYSREG_LIST(WRITE, (val))	\
+	ETE_ONLY_SYSREG_LIST(WRITE, (val))
+
+#define ETE_ONLY_SYSREG_LIST_CASES		\
+	ETE_ONLY_SYSREG_LIST(NOP, __unused)
+
 #define read_etm4x_sysreg_offset(offset, _64bit)				\
 	({									\
 		u64 __val;							\
@@ -506,6 +544,20 @@
 					 ETM_MODE_EXCL_USER)
 
 /*
+ * TRCOSLSR.OSLM advertises the OS Lock model.
+ * OSLM[2:0] = TRCOSLSR[4:3,0]
+ *
+ *	0b000 - Trace OS Lock is not implemented.
+ *	0b010 - Trace OS Lock is implemented.
+ *	0b100 - Trace OS Lock is not implemented, unit is controlled by PE OS Lock.
+ */
+#define ETM_OSLOCK_NI		0b000
+#define ETM_OSLOCK_PRESENT	0b010
+#define ETM_OSLOCK_PE		0b100
+
+#define ETM_OSLSR_OSLM(oslsr)	((((oslsr) & GENMASK(4, 3)) >> 2) | (oslsr & 0x1))
+
+/*
  * TRCDEVARCH Bit field definitions
  * Bits[31:21]	- ARCHITECT = Always Arm Ltd.
  *                * Bits[31:28] = 0x4
@@ -541,11 +593,14 @@
 	((ETM_DEVARCH_MAKE_ARCHID_ARCH_VER(major)) | ETM_DEVARCH_ARCHID_ARCH_PART(0xA13))
 
 #define ETM_DEVARCH_ARCHID_ETMv4x		ETM_DEVARCH_MAKE_ARCHID(0x4)
+#define ETM_DEVARCH_ARCHID_ETE			ETM_DEVARCH_MAKE_ARCHID(0x5)
 
 #define ETM_DEVARCH_ID_MASK						\
 	(ETM_DEVARCH_ARCHITECT_MASK | ETM_DEVARCH_ARCHID_MASK | ETM_DEVARCH_PRESENT)
 #define ETM_DEVARCH_ETMv4x_ARCH						\
 	(ETM_DEVARCH_ARCHITECT_ARM | ETM_DEVARCH_ARCHID_ETMv4x | ETM_DEVARCH_PRESENT)
+#define ETM_DEVARCH_ETE_ARCH						\
+	(ETM_DEVARCH_ARCHITECT_ARM | ETM_DEVARCH_ARCHID_ETE | ETM_DEVARCH_PRESENT)
 
 #define TRCSTATR_IDLE_BIT		0
 #define TRCSTATR_PMSTABLE_BIT		1
@@ -635,6 +690,8 @@
 #define ETM_ARCH_MINOR_VERSION(arch)	((arch) & 0xfU)
 
 #define ETM_ARCH_V4	ETM_ARCH_VERSION(4, 0)
+#define ETM_ARCH_ETE	ETM_ARCH_VERSION(5, 0)
+
 /* Interpretation of resource numbers change at ETM v4.3 architecture */
 #define ETM_ARCH_V4_3	ETM_ARCH_VERSION(4, 3)
 
@@ -862,6 +919,7 @@ struct etmv4_save_state {
  * @nooverflow:	Indicate if overflow prevention is supported.
  * @atbtrig:	If the implementation can support ATB triggers
  * @lpoverride:	If the implementation can support low-power state over.
+ * @trfc:	If the implementation supports Arm v8.4 trace filter controls.
  * @config:	structure holding configuration parameters.
  * @save_state:	State to be preserved across power loss
  * @state_needs_restore: True when there is context to restore after PM exit
@@ -897,6 +955,7 @@ struct etmv4_drvdata {
 	u8				s_ex_level;
 	u8				ns_ex_level;
 	u8				q_support;
+	u8				os_lock_model;
 	bool				sticky_enable;
 	bool				boot_enable;
 	bool				os_unlock;
@@ -912,6 +971,7 @@ struct etmv4_drvdata {
 	bool				nooverflow;
 	bool				atbtrig;
 	bool				lpoverride;
+	bool				trfc;
 	struct etmv4_config		config;
 	struct etmv4_save_state		*save_state;
 	bool				state_needs_restore;
@@ -940,4 +1000,9 @@ void etm4_config_trace_mode(struct etmv4_config *config);
 
 u64 etm4x_sysreg_read(u32 offset, bool _relaxed, bool _64bit);
 void etm4x_sysreg_write(u64 val, u32 offset, bool _relaxed, bool _64bit);
+
+static inline bool etm4x_is_ete(struct etmv4_drvdata *drvdata)
+{
+	return drvdata->arch >= ETM_ARCH_ETE;
+}
 #endif
diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c
index 3629b7885aca..c594f45319fc 100644
--- a/drivers/hwtracing/coresight/coresight-platform.c
+++ b/drivers/hwtracing/coresight/coresight-platform.c
@@ -90,6 +90,12 @@ static void of_coresight_get_ports_legacy(const struct device_node *node,
 	struct of_endpoint endpoint;
 	int in = 0, out = 0;
 
+	/*
+	 * Avoid warnings in of_graph_get_next_endpoint()
+	 * if the device doesn't have any graph connections
+	 */
+	if (!of_graph_is_present(node))
+		return;
 	do {
 		ep = of_graph_get_next_endpoint(node, ep);
 		if (!ep)
diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
index f5f654ea2994..ff1dd2092ac5 100644
--- a/drivers/hwtracing/coresight/coresight-priv.h
+++ b/drivers/hwtracing/coresight/coresight-priv.h
@@ -232,4 +232,7 @@ coresight_find_csdev_by_fwnode(struct fwnode_handle *r_fwnode);
 void coresight_set_assoc_ectdev_mutex(struct coresight_device *csdev,
 				      struct coresight_device *ect_csdev);
 
+void coresight_set_percpu_sink(int cpu, struct coresight_device *csdev);
+struct coresight_device *coresight_get_percpu_sink(int cpu);
+
 #endif
diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
new file mode 100644
index 000000000000..176868496879
--- /dev/null
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -0,0 +1,1157 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This driver enables Trace Buffer Extension (TRBE) as a per-cpu coresight
+ * sink device could then pair with an appropriate per-cpu coresight source
+ * device (ETE) thus generating required trace data. Trace can be enabled
+ * via the perf framework.
+ *
+ * The AUX buffer handling is inspired from Arm SPE PMU driver.
+ *
+ * Copyright (C) 2020 ARM Ltd.
+ *
+ * Author: Anshuman Khandual <anshuman.khandual@arm.com>
+ */
+#define DRVNAME "arm_trbe"
+
+#define pr_fmt(fmt) DRVNAME ": " fmt
+
+#include <asm/barrier.h>
+#include "coresight-trbe.h"
+
+#define PERF_IDX2OFF(idx, buf) ((idx) % ((buf)->nr_pages << PAGE_SHIFT))
+
+/*
+ * A padding packet that will help the user space tools
+ * in skipping relevant sections in the captured trace
+ * data which could not be decoded. TRBE doesn't support
+ * formatting the trace data, unlike the legacy CoreSight
+ * sinks and thus we use ETE trace packets to pad the
+ * sections of the buffer.
+ */
+#define ETE_IGNORE_PACKET		0x70
+
+/*
+ * Minimum amount of meaningful trace will contain:
+ * A-Sync, Trace Info, Trace On, Address, Atom.
+ * This is about 44bytes of ETE trace. To be on
+ * the safer side, we assume 64bytes is the minimum
+ * space required for a meaningful session, before
+ * we hit a "WRAP" event.
+ */
+#define TRBE_TRACE_MIN_BUF_SIZE		64
+
+enum trbe_fault_action {
+	TRBE_FAULT_ACT_WRAP,
+	TRBE_FAULT_ACT_SPURIOUS,
+	TRBE_FAULT_ACT_FATAL,
+};
+
+struct trbe_buf {
+	/*
+	 * Even though trbe_base represents vmap()
+	 * mapped allocated buffer's start address,
+	 * it's being as unsigned long for various
+	 * arithmetic and comparision operations &
+	 * also to be consistent with trbe_write &
+	 * trbe_limit sibling pointers.
+	 */
+	unsigned long trbe_base;
+	unsigned long trbe_limit;
+	unsigned long trbe_write;
+	int nr_pages;
+	void **pages;
+	bool snapshot;
+	struct trbe_cpudata *cpudata;
+};
+
+struct trbe_cpudata {
+	bool trbe_flag;
+	u64 trbe_align;
+	int cpu;
+	enum cs_mode mode;
+	struct trbe_buf *buf;
+	struct trbe_drvdata *drvdata;
+};
+
+struct trbe_drvdata {
+	struct trbe_cpudata __percpu *cpudata;
+	struct perf_output_handle * __percpu *handle;
+	struct hlist_node hotplug_node;
+	int irq;
+	cpumask_t supported_cpus;
+	enum cpuhp_state trbe_online;
+	struct platform_device *pdev;
+};
+
+static int trbe_alloc_node(struct perf_event *event)
+{
+	if (event->cpu == -1)
+		return NUMA_NO_NODE;
+	return cpu_to_node(event->cpu);
+}
+
+static void trbe_drain_buffer(void)
+{
+	tsb_csync();
+	dsb(nsh);
+}
+
+static void trbe_drain_and_disable_local(void)
+{
+	u64 trblimitr = read_sysreg_s(SYS_TRBLIMITR_EL1);
+
+	trbe_drain_buffer();
+
+	/*
+	 * Disable the TRBE without clearing LIMITPTR which
+	 * might be required for fetching the buffer limits.
+	 */
+	trblimitr &= ~TRBLIMITR_ENABLE;
+	write_sysreg_s(trblimitr, SYS_TRBLIMITR_EL1);
+	isb();
+}
+
+static void trbe_reset_local(void)
+{
+	trbe_drain_and_disable_local();
+	write_sysreg_s(0, SYS_TRBLIMITR_EL1);
+	write_sysreg_s(0, SYS_TRBPTR_EL1);
+	write_sysreg_s(0, SYS_TRBBASER_EL1);
+	write_sysreg_s(0, SYS_TRBSR_EL1);
+}
+
+static void trbe_stop_and_truncate_event(struct perf_output_handle *handle)
+{
+	struct trbe_buf *buf = etm_perf_sink_config(handle);
+
+	/*
+	 * We cannot proceed with the buffer collection and we
+	 * do not have any data for the current session. The
+	 * etm_perf driver expects to close out the aux_buffer
+	 * at event_stop(). So disable the TRBE here and leave
+	 * the update_buffer() to return a 0 size.
+	 */
+	trbe_drain_and_disable_local();
+	perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
+	*this_cpu_ptr(buf->cpudata->drvdata->handle) = NULL;
+}
+
+/*
+ * TRBE Buffer Management
+ *
+ * The TRBE buffer spans from the base pointer till the limit pointer. When enabled,
+ * it starts writing trace data from the write pointer onward till the limit pointer.
+ * When the write pointer reaches the address just before the limit pointer, it gets
+ * wrapped around again to the base pointer. This is called a TRBE wrap event, which
+ * generates a maintenance interrupt when operated in WRAP or FILL mode. This driver
+ * uses FILL mode, where the TRBE stops the trace collection at wrap event. The IRQ
+ * handler updates the AUX buffer and re-enables the TRBE with updated WRITE and
+ * LIMIT pointers.
+ *
+ *	Wrap around with an IRQ
+ *	------ < ------ < ------- < ----- < -----
+ *	|					|
+ *	------ > ------ > ------- > ----- > -----
+ *
+ *	+---------------+-----------------------+
+ *	|		|			|
+ *	+---------------+-----------------------+
+ *	Base Pointer	Write Pointer		Limit Pointer
+ *
+ * The base and limit pointers always needs to be PAGE_SIZE aligned. But the write
+ * pointer can be aligned to the implementation defined TRBE trace buffer alignment
+ * as captured in trbe_cpudata->trbe_align.
+ *
+ *
+ *		head		tail		wakeup
+ *	+---------------------------------------+----- ~ ~ ------
+ *	|$$$$$$$|################|$$$$$$$$$$$$$$|		|
+ *	+---------------------------------------+----- ~ ~ ------
+ *	Base Pointer	Write Pointer		Limit Pointer
+ *
+ * The perf_output_handle indices (head, tail, wakeup) are monotonically increasing
+ * values which tracks all the driver writes and user reads from the perf auxiliary
+ * buffer. Generally [head..tail] is the area where the driver can write into unless
+ * the wakeup is behind the tail. Enabled TRBE buffer span needs to be adjusted and
+ * configured depending on the perf_output_handle indices, so that the driver does
+ * not override into areas in the perf auxiliary buffer which is being or yet to be
+ * consumed from the user space. The enabled TRBE buffer area is a moving subset of
+ * the allocated perf auxiliary buffer.
+ */
+static void trbe_pad_buf(struct perf_output_handle *handle, int len)
+{
+	struct trbe_buf *buf = etm_perf_sink_config(handle);
+	u64 head = PERF_IDX2OFF(handle->head, buf);
+
+	memset((void *)buf->trbe_base + head, ETE_IGNORE_PACKET, len);
+	if (!buf->snapshot)
+		perf_aux_output_skip(handle, len);
+}
+
+static unsigned long trbe_snapshot_offset(struct perf_output_handle *handle)
+{
+	struct trbe_buf *buf = etm_perf_sink_config(handle);
+
+	/*
+	 * The ETE trace has alignment synchronization packets allowing
+	 * the decoder to reset in case of an overflow or corruption.
+	 * So we can use the entire buffer for the snapshot mode.
+	 */
+	return buf->nr_pages * PAGE_SIZE;
+}
+
+/*
+ * TRBE Limit Calculation
+ *
+ * The following markers are used to illustrate various TRBE buffer situations.
+ *
+ * $$$$ - Data area, unconsumed captured trace data, not to be overridden
+ * #### - Free area, enabled, trace will be written
+ * %%%% - Free area, disabled, trace will not be written
+ * ==== - Free area, padded with ETE_IGNORE_PACKET, trace will be skipped
+ */
+static unsigned long __trbe_normal_offset(struct perf_output_handle *handle)
+{
+	struct trbe_buf *buf = etm_perf_sink_config(handle);
+	struct trbe_cpudata *cpudata = buf->cpudata;
+	const u64 bufsize = buf->nr_pages * PAGE_SIZE;
+	u64 limit = bufsize;
+	u64 head, tail, wakeup;
+
+	head = PERF_IDX2OFF(handle->head, buf);
+
+	/*
+	 *		head
+	 *	------->|
+	 *	|
+	 *	head	TRBE align	tail
+	 * +----|-------|---------------|-------+
+	 * |$$$$|=======|###############|$$$$$$$|
+	 * +----|-------|---------------|-------+
+	 * trbe_base				trbe_base + nr_pages
+	 *
+	 * Perf aux buffer output head position can be misaligned depending on
+	 * various factors including user space reads. In case misaligned, head
+	 * needs to be aligned before TRBE can be configured. Pad the alignment
+	 * gap with ETE_IGNORE_PACKET bytes that will be ignored by user tools
+	 * and skip this section thus advancing the head.
+	 */
+	if (!IS_ALIGNED(head, cpudata->trbe_align)) {
+		unsigned long delta = roundup(head, cpudata->trbe_align) - head;
+
+		delta = min(delta, handle->size);
+		trbe_pad_buf(handle, delta);
+		head = PERF_IDX2OFF(handle->head, buf);
+	}
+
+	/*
+	 *	head = tail (size = 0)
+	 * +----|-------------------------------+
+	 * |$$$$|$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$	|
+	 * +----|-------------------------------+
+	 * trbe_base				trbe_base + nr_pages
+	 *
+	 * Perf aux buffer does not have any space for the driver to write into.
+	 * Just communicate trace truncation event to the user space by marking
+	 * it with PERF_AUX_FLAG_TRUNCATED.
+	 */
+	if (!handle->size) {
+		perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
+		return 0;
+	}
+
+	/* Compute the tail and wakeup indices now that we've aligned head */
+	tail = PERF_IDX2OFF(handle->head + handle->size, buf);
+	wakeup = PERF_IDX2OFF(handle->wakeup, buf);
+
+	/*
+	 * Lets calculate the buffer area which TRBE could write into. There
+	 * are three possible scenarios here. Limit needs to be aligned with
+	 * PAGE_SIZE per the TRBE requirement. Always avoid clobbering the
+	 * unconsumed data.
+	 *
+	 * 1) head < tail
+	 *
+	 *	head			tail
+	 * +----|-----------------------|-------+
+	 * |$$$$|#######################|$$$$$$$|
+	 * +----|-----------------------|-------+
+	 * trbe_base			limit	trbe_base + nr_pages
+	 *
+	 * TRBE could write into [head..tail] area. Unless the tail is right at
+	 * the end of the buffer, neither an wrap around nor an IRQ is expected
+	 * while being enabled.
+	 *
+	 * 2) head == tail
+	 *
+	 *	head = tail (size > 0)
+	 * +----|-------------------------------+
+	 * |%%%%|###############################|
+	 * +----|-------------------------------+
+	 * trbe_base				limit = trbe_base + nr_pages
+	 *
+	 * TRBE should just write into [head..base + nr_pages] area even though
+	 * the entire buffer is empty. Reason being, when the trace reaches the
+	 * end of the buffer, it will just wrap around with an IRQ giving an
+	 * opportunity to reconfigure the buffer.
+	 *
+	 * 3) tail < head
+	 *
+	 *	tail			head
+	 * +----|-----------------------|-------+
+	 * |%%%%|$$$$$$$$$$$$$$$$$$$$$$$|#######|
+	 * +----|-----------------------|-------+
+	 * trbe_base				limit = trbe_base + nr_pages
+	 *
+	 * TRBE should just write into [head..base + nr_pages] area even though
+	 * the [trbe_base..tail] is also empty. Reason being, when the trace
+	 * reaches the end of the buffer, it will just wrap around with an IRQ
+	 * giving an opportunity to reconfigure the buffer.
+	 */
+	if (head < tail)
+		limit = round_down(tail, PAGE_SIZE);
+
+	/*
+	 * Wakeup may be arbitrarily far into the future. If it's not in the
+	 * current generation, either we'll wrap before hitting it, or it's
+	 * in the past and has been handled already.
+	 *
+	 * If there's a wakeup before we wrap, arrange to be woken up by the
+	 * page boundary following it. Keep the tail boundary if that's lower.
+	 *
+	 *	head		wakeup	tail
+	 * +----|---------------|-------|-------+
+	 * |$$$$|###############|%%%%%%%|$$$$$$$|
+	 * +----|---------------|-------|-------+
+	 * trbe_base		limit		trbe_base + nr_pages
+	 */
+	if (handle->wakeup < (handle->head + handle->size) && head <= wakeup)
+		limit = min(limit, round_up(wakeup, PAGE_SIZE));
+
+	/*
+	 * There are two situation when this can happen i.e limit is before
+	 * the head and hence TRBE cannot be configured.
+	 *
+	 * 1) head < tail (aligned down with PAGE_SIZE) and also they are both
+	 * within the same PAGE size range.
+	 *
+	 *			PAGE_SIZE
+	 *		|----------------------|
+	 *
+	 *		limit	head	tail
+	 * +------------|------|--------|-------+
+	 * |$$$$$$$$$$$$$$$$$$$|========|$$$$$$$|
+	 * +------------|------|--------|-------+
+	 * trbe_base				trbe_base + nr_pages
+	 *
+	 * 2) head < wakeup (aligned up with PAGE_SIZE) < tail and also both
+	 * head and wakeup are within same PAGE size range.
+	 *
+	 *		PAGE_SIZE
+	 *	|----------------------|
+	 *
+	 *	limit	head	wakeup  tail
+	 * +----|------|-------|--------|-------+
+	 * |$$$$$$$$$$$|=======|========|$$$$$$$|
+	 * +----|------|-------|--------|-------+
+	 * trbe_base				trbe_base + nr_pages
+	 */
+	if (limit > head)
+		return limit;
+
+	trbe_pad_buf(handle, handle->size);
+	perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
+	return 0;
+}
+
+static unsigned long trbe_normal_offset(struct perf_output_handle *handle)
+{
+	struct trbe_buf *buf = perf_get_aux(handle);
+	u64 limit = __trbe_normal_offset(handle);
+	u64 head = PERF_IDX2OFF(handle->head, buf);
+
+	/*
+	 * If the head is too close to the limit and we don't
+	 * have space for a meaningful run, we rather pad it
+	 * and start fresh.
+	 */
+	if (limit && (limit - head < TRBE_TRACE_MIN_BUF_SIZE)) {
+		trbe_pad_buf(handle, limit - head);
+		limit = __trbe_normal_offset(handle);
+	}
+	return limit;
+}
+
+static unsigned long compute_trbe_buffer_limit(struct perf_output_handle *handle)
+{
+	struct trbe_buf *buf = etm_perf_sink_config(handle);
+	unsigned long offset;
+
+	if (buf->snapshot)
+		offset = trbe_snapshot_offset(handle);
+	else
+		offset = trbe_normal_offset(handle);
+	return buf->trbe_base + offset;
+}
+
+static void clr_trbe_status(void)
+{
+	u64 trbsr = read_sysreg_s(SYS_TRBSR_EL1);
+
+	WARN_ON(is_trbe_enabled());
+	trbsr &= ~TRBSR_IRQ;
+	trbsr &= ~TRBSR_TRG;
+	trbsr &= ~TRBSR_WRAP;
+	trbsr &= ~(TRBSR_EC_MASK << TRBSR_EC_SHIFT);
+	trbsr &= ~(TRBSR_BSC_MASK << TRBSR_BSC_SHIFT);
+	trbsr &= ~TRBSR_STOP;
+	write_sysreg_s(trbsr, SYS_TRBSR_EL1);
+}
+
+static void set_trbe_limit_pointer_enabled(unsigned long addr)
+{
+	u64 trblimitr = read_sysreg_s(SYS_TRBLIMITR_EL1);
+
+	WARN_ON(!IS_ALIGNED(addr, (1UL << TRBLIMITR_LIMIT_SHIFT)));
+	WARN_ON(!IS_ALIGNED(addr, PAGE_SIZE));
+
+	trblimitr &= ~TRBLIMITR_NVM;
+	trblimitr &= ~(TRBLIMITR_FILL_MODE_MASK << TRBLIMITR_FILL_MODE_SHIFT);
+	trblimitr &= ~(TRBLIMITR_TRIG_MODE_MASK << TRBLIMITR_TRIG_MODE_SHIFT);
+	trblimitr &= ~(TRBLIMITR_LIMIT_MASK << TRBLIMITR_LIMIT_SHIFT);
+
+	/*
+	 * Fill trace buffer mode is used here while configuring the
+	 * TRBE for trace capture. In this particular mode, the trace
+	 * collection is stopped and a maintenance interrupt is raised
+	 * when the current write pointer wraps. This pause in trace
+	 * collection gives the software an opportunity to capture the
+	 * trace data in the interrupt handler, before reconfiguring
+	 * the TRBE.
+	 */
+	trblimitr |= (TRBE_FILL_MODE_FILL & TRBLIMITR_FILL_MODE_MASK) << TRBLIMITR_FILL_MODE_SHIFT;
+
+	/*
+	 * Trigger mode is not used here while configuring the TRBE for
+	 * the trace capture. Hence just keep this in the ignore mode.
+	 */
+	trblimitr |= (TRBE_TRIG_MODE_IGNORE & TRBLIMITR_TRIG_MODE_MASK) <<
+		      TRBLIMITR_TRIG_MODE_SHIFT;
+	trblimitr |= (addr & PAGE_MASK);
+
+	trblimitr |= TRBLIMITR_ENABLE;
+	write_sysreg_s(trblimitr, SYS_TRBLIMITR_EL1);
+
+	/* Synchronize the TRBE enable event */
+	isb();
+}
+
+static void trbe_enable_hw(struct trbe_buf *buf)
+{
+	WARN_ON(buf->trbe_write < buf->trbe_base);
+	WARN_ON(buf->trbe_write >= buf->trbe_limit);
+	set_trbe_disabled();
+	isb();
+	clr_trbe_status();
+	set_trbe_base_pointer(buf->trbe_base);
+	set_trbe_write_pointer(buf->trbe_write);
+
+	/*
+	 * Synchronize all the register updates
+	 * till now before enabling the TRBE.
+	 */
+	isb();
+	set_trbe_limit_pointer_enabled(buf->trbe_limit);
+}
+
+static enum trbe_fault_action trbe_get_fault_act(u64 trbsr)
+{
+	int ec = get_trbe_ec(trbsr);
+	int bsc = get_trbe_bsc(trbsr);
+
+	WARN_ON(is_trbe_running(trbsr));
+	if (is_trbe_trg(trbsr) || is_trbe_abort(trbsr))
+		return TRBE_FAULT_ACT_FATAL;
+
+	if ((ec == TRBE_EC_STAGE1_ABORT) || (ec == TRBE_EC_STAGE2_ABORT))
+		return TRBE_FAULT_ACT_FATAL;
+
+	if (is_trbe_wrap(trbsr) && (ec == TRBE_EC_OTHERS) && (bsc == TRBE_BSC_FILLED)) {
+		if (get_trbe_write_pointer() == get_trbe_base_pointer())
+			return TRBE_FAULT_ACT_WRAP;
+	}
+	return TRBE_FAULT_ACT_SPURIOUS;
+}
+
+static void *arm_trbe_alloc_buffer(struct coresight_device *csdev,
+				   struct perf_event *event, void **pages,
+				   int nr_pages, bool snapshot)
+{
+	struct trbe_buf *buf;
+	struct page **pglist;
+	int i;
+
+	/*
+	 * TRBE LIMIT and TRBE WRITE pointers must be page aligned. But with
+	 * just a single page, there would not be any room left while writing
+	 * into a partially filled TRBE buffer after the page size alignment.
+	 * Hence restrict the minimum buffer size as two pages.
+	 */
+	if (nr_pages < 2)
+		return NULL;
+
+	buf = kzalloc_node(sizeof(*buf), GFP_KERNEL, trbe_alloc_node(event));
+	if (!buf)
+		return ERR_PTR(-ENOMEM);
+
+	pglist = kcalloc(nr_pages, sizeof(*pglist), GFP_KERNEL);
+	if (!pglist) {
+		kfree(buf);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	for (i = 0; i < nr_pages; i++)
+		pglist[i] = virt_to_page(pages[i]);
+
+	buf->trbe_base = (unsigned long)vmap(pglist, nr_pages, VM_MAP, PAGE_KERNEL);
+	if (!buf->trbe_base) {
+		kfree(pglist);
+		kfree(buf);
+		return ERR_PTR(-ENOMEM);
+	}
+	buf->trbe_limit = buf->trbe_base + nr_pages * PAGE_SIZE;
+	buf->trbe_write = buf->trbe_base;
+	buf->snapshot = snapshot;
+	buf->nr_pages = nr_pages;
+	buf->pages = pages;
+	kfree(pglist);
+	return buf;
+}
+
+static void arm_trbe_free_buffer(void *config)
+{
+	struct trbe_buf *buf = config;
+
+	vunmap((void *)buf->trbe_base);
+	kfree(buf);
+}
+
+static unsigned long arm_trbe_update_buffer(struct coresight_device *csdev,
+					    struct perf_output_handle *handle,
+					    void *config)
+{
+	struct trbe_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+	struct trbe_cpudata *cpudata = dev_get_drvdata(&csdev->dev);
+	struct trbe_buf *buf = config;
+	enum trbe_fault_action act;
+	unsigned long size, offset;
+	unsigned long write, base, status;
+	unsigned long flags;
+
+	WARN_ON(buf->cpudata != cpudata);
+	WARN_ON(cpudata->cpu != smp_processor_id());
+	WARN_ON(cpudata->drvdata != drvdata);
+	if (cpudata->mode != CS_MODE_PERF)
+		return 0;
+
+	perf_aux_output_flag(handle, PERF_AUX_FLAG_CORESIGHT_FORMAT_RAW);
+
+	/*
+	 * We are about to disable the TRBE. And this could in turn
+	 * fill up the buffer triggering, an IRQ. This could be consumed
+	 * by the PE asynchronously, causing a race here against
+	 * the IRQ handler in closing out the handle. So, let us
+	 * make sure the IRQ can't trigger while we are collecting
+	 * the buffer. We also make sure that a WRAP event is handled
+	 * accordingly.
+	 */
+	local_irq_save(flags);
+
+	/*
+	 * If the TRBE was disabled due to lack of space in the AUX buffer or a
+	 * spurious fault, the driver leaves it disabled, truncating the buffer.
+	 * Since the etm_perf driver expects to close out the AUX buffer, the
+	 * driver skips it. Thus, just pass in 0 size here to indicate that the
+	 * buffer was truncated.
+	 */
+	if (!is_trbe_enabled()) {
+		size = 0;
+		goto done;
+	}
+	/*
+	 * perf handle structure needs to be shared with the TRBE IRQ handler for
+	 * capturing trace data and restarting the handle. There is a probability
+	 * of an undefined reference based crash when etm event is being stopped
+	 * while a TRBE IRQ also getting processed. This happens due the release
+	 * of perf handle via perf_aux_output_end() in etm_event_stop(). Stopping
+	 * the TRBE here will ensure that no IRQ could be generated when the perf
+	 * handle gets freed in etm_event_stop().
+	 */
+	trbe_drain_and_disable_local();
+	write = get_trbe_write_pointer();
+	base = get_trbe_base_pointer();
+
+	/* Check if there is a pending interrupt and handle it here */
+	status = read_sysreg_s(SYS_TRBSR_EL1);
+	if (is_trbe_irq(status)) {
+
+		/*
+		 * Now that we are handling the IRQ here, clear the IRQ
+		 * from the status, to let the irq handler know that it
+		 * is taken care of.
+		 */
+		clr_trbe_irq();
+		isb();
+
+		act = trbe_get_fault_act(status);
+		/*
+		 * If this was not due to a WRAP event, we have some
+		 * errors and as such buffer is empty.
+		 */
+		if (act != TRBE_FAULT_ACT_WRAP) {
+			size = 0;
+			goto done;
+		}
+
+		/*
+		 * Otherwise, the buffer is full and the write pointer
+		 * has reached base. Adjust this back to the Limit pointer
+		 * for correct size. Also, mark the buffer truncated.
+		 */
+		write = get_trbe_limit_pointer();
+		perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
+	}
+
+	offset = write - base;
+	if (WARN_ON_ONCE(offset < PERF_IDX2OFF(handle->head, buf)))
+		size = 0;
+	else
+		size = offset - PERF_IDX2OFF(handle->head, buf);
+
+done:
+	local_irq_restore(flags);
+
+	if (buf->snapshot)
+		handle->head += size;
+	return size;
+}
+
+static int arm_trbe_enable(struct coresight_device *csdev, u32 mode, void *data)
+{
+	struct trbe_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+	struct trbe_cpudata *cpudata = dev_get_drvdata(&csdev->dev);
+	struct perf_output_handle *handle = data;
+	struct trbe_buf *buf = etm_perf_sink_config(handle);
+
+	WARN_ON(cpudata->cpu != smp_processor_id());
+	WARN_ON(cpudata->drvdata != drvdata);
+	if (mode != CS_MODE_PERF)
+		return -EINVAL;
+
+	*this_cpu_ptr(drvdata->handle) = handle;
+	cpudata->buf = buf;
+	cpudata->mode = mode;
+	buf->cpudata = cpudata;
+	buf->trbe_limit = compute_trbe_buffer_limit(handle);
+	buf->trbe_write = buf->trbe_base + PERF_IDX2OFF(handle->head, buf);
+	if (buf->trbe_limit == buf->trbe_base) {
+		trbe_stop_and_truncate_event(handle);
+		return 0;
+	}
+	trbe_enable_hw(buf);
+	return 0;
+}
+
+static int arm_trbe_disable(struct coresight_device *csdev)
+{
+	struct trbe_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+	struct trbe_cpudata *cpudata = dev_get_drvdata(&csdev->dev);
+	struct trbe_buf *buf = cpudata->buf;
+
+	WARN_ON(buf->cpudata != cpudata);
+	WARN_ON(cpudata->cpu != smp_processor_id());
+	WARN_ON(cpudata->drvdata != drvdata);
+	if (cpudata->mode != CS_MODE_PERF)
+		return -EINVAL;
+
+	trbe_drain_and_disable_local();
+	buf->cpudata = NULL;
+	cpudata->buf = NULL;
+	cpudata->mode = CS_MODE_DISABLED;
+	return 0;
+}
+
+static void trbe_handle_spurious(struct perf_output_handle *handle)
+{
+	struct trbe_buf *buf = etm_perf_sink_config(handle);
+
+	buf->trbe_limit = compute_trbe_buffer_limit(handle);
+	buf->trbe_write = buf->trbe_base + PERF_IDX2OFF(handle->head, buf);
+	if (buf->trbe_limit == buf->trbe_base) {
+		trbe_drain_and_disable_local();
+		return;
+	}
+	trbe_enable_hw(buf);
+}
+
+static void trbe_handle_overflow(struct perf_output_handle *handle)
+{
+	struct perf_event *event = handle->event;
+	struct trbe_buf *buf = etm_perf_sink_config(handle);
+	unsigned long offset, size;
+	struct etm_event_data *event_data;
+
+	offset = get_trbe_limit_pointer() - get_trbe_base_pointer();
+	size = offset - PERF_IDX2OFF(handle->head, buf);
+	if (buf->snapshot)
+		handle->head += size;
+
+	/*
+	 * Mark the buffer as truncated, as we have stopped the trace
+	 * collection upon the WRAP event, without stopping the source.
+	 */
+	perf_aux_output_flag(handle, PERF_AUX_FLAG_CORESIGHT_FORMAT_RAW |
+				     PERF_AUX_FLAG_TRUNCATED);
+	perf_aux_output_end(handle, size);
+	event_data = perf_aux_output_begin(handle, event);
+	if (!event_data) {
+		/*
+		 * We are unable to restart the trace collection,
+		 * thus leave the TRBE disabled. The etm-perf driver
+		 * is able to detect this with a disconnected handle
+		 * (handle->event = NULL).
+		 */
+		trbe_drain_and_disable_local();
+		*this_cpu_ptr(buf->cpudata->drvdata->handle) = NULL;
+		return;
+	}
+	buf->trbe_limit = compute_trbe_buffer_limit(handle);
+	buf->trbe_write = buf->trbe_base + PERF_IDX2OFF(handle->head, buf);
+	if (buf->trbe_limit == buf->trbe_base) {
+		trbe_stop_and_truncate_event(handle);
+		return;
+	}
+	*this_cpu_ptr(buf->cpudata->drvdata->handle) = handle;
+	trbe_enable_hw(buf);
+}
+
+static bool is_perf_trbe(struct perf_output_handle *handle)
+{
+	struct trbe_buf *buf = etm_perf_sink_config(handle);
+	struct trbe_cpudata *cpudata = buf->cpudata;
+	struct trbe_drvdata *drvdata = cpudata->drvdata;
+	int cpu = smp_processor_id();
+
+	WARN_ON(buf->trbe_base != get_trbe_base_pointer());
+	WARN_ON(buf->trbe_limit != get_trbe_limit_pointer());
+
+	if (cpudata->mode != CS_MODE_PERF)
+		return false;
+
+	if (cpudata->cpu != cpu)
+		return false;
+
+	if (!cpumask_test_cpu(cpu, &drvdata->supported_cpus))
+		return false;
+
+	return true;
+}
+
+static irqreturn_t arm_trbe_irq_handler(int irq, void *dev)
+{
+	struct perf_output_handle **handle_ptr = dev;
+	struct perf_output_handle *handle = *handle_ptr;
+	enum trbe_fault_action act;
+	u64 status;
+
+	/*
+	 * Ensure the trace is visible to the CPUs and
+	 * any external aborts have been resolved.
+	 */
+	trbe_drain_and_disable_local();
+
+	status = read_sysreg_s(SYS_TRBSR_EL1);
+	/*
+	 * If the pending IRQ was handled by update_buffer callback
+	 * we have nothing to do here.
+	 */
+	if (!is_trbe_irq(status))
+		return IRQ_NONE;
+
+	clr_trbe_irq();
+	isb();
+
+	if (WARN_ON_ONCE(!handle) || !perf_get_aux(handle))
+		return IRQ_NONE;
+
+	if (!is_perf_trbe(handle))
+		return IRQ_NONE;
+
+	/*
+	 * Ensure perf callbacks have completed, which may disable
+	 * the trace buffer in response to a TRUNCATION flag.
+	 */
+	irq_work_run();
+
+	act = trbe_get_fault_act(status);
+	switch (act) {
+	case TRBE_FAULT_ACT_WRAP:
+		trbe_handle_overflow(handle);
+		break;
+	case TRBE_FAULT_ACT_SPURIOUS:
+		trbe_handle_spurious(handle);
+		break;
+	case TRBE_FAULT_ACT_FATAL:
+		trbe_stop_and_truncate_event(handle);
+		break;
+	}
+	return IRQ_HANDLED;
+}
+
+static const struct coresight_ops_sink arm_trbe_sink_ops = {
+	.enable		= arm_trbe_enable,
+	.disable	= arm_trbe_disable,
+	.alloc_buffer	= arm_trbe_alloc_buffer,
+	.free_buffer	= arm_trbe_free_buffer,
+	.update_buffer	= arm_trbe_update_buffer,
+};
+
+static const struct coresight_ops arm_trbe_cs_ops = {
+	.sink_ops	= &arm_trbe_sink_ops,
+};
+
+static ssize_t align_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct trbe_cpudata *cpudata = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%llx\n", cpudata->trbe_align);
+}
+static DEVICE_ATTR_RO(align);
+
+static ssize_t flag_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct trbe_cpudata *cpudata = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%d\n", cpudata->trbe_flag);
+}
+static DEVICE_ATTR_RO(flag);
+
+static struct attribute *arm_trbe_attrs[] = {
+	&dev_attr_align.attr,
+	&dev_attr_flag.attr,
+	NULL,
+};
+
+static const struct attribute_group arm_trbe_group = {
+	.attrs = arm_trbe_attrs,
+};
+
+static const struct attribute_group *arm_trbe_groups[] = {
+	&arm_trbe_group,
+	NULL,
+};
+
+static void arm_trbe_enable_cpu(void *info)
+{
+	struct trbe_drvdata *drvdata = info;
+
+	trbe_reset_local();
+	enable_percpu_irq(drvdata->irq, IRQ_TYPE_NONE);
+}
+
+static void arm_trbe_register_coresight_cpu(struct trbe_drvdata *drvdata, int cpu)
+{
+	struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
+	struct coresight_device *trbe_csdev = coresight_get_percpu_sink(cpu);
+	struct coresight_desc desc = { 0 };
+	struct device *dev;
+
+	if (WARN_ON(trbe_csdev))
+		return;
+
+	dev = &cpudata->drvdata->pdev->dev;
+	desc.name = devm_kasprintf(dev, GFP_KERNEL, "trbe%d", cpu);
+	if (!desc.name)
+		goto cpu_clear;
+
+	desc.type = CORESIGHT_DEV_TYPE_SINK;
+	desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_PERCPU_SYSMEM;
+	desc.ops = &arm_trbe_cs_ops;
+	desc.pdata = dev_get_platdata(dev);
+	desc.groups = arm_trbe_groups;
+	desc.dev = dev;
+	trbe_csdev = coresight_register(&desc);
+	if (IS_ERR(trbe_csdev))
+		goto cpu_clear;
+
+	dev_set_drvdata(&trbe_csdev->dev, cpudata);
+	coresight_set_percpu_sink(cpu, trbe_csdev);
+	return;
+cpu_clear:
+	cpumask_clear_cpu(cpu, &drvdata->supported_cpus);
+}
+
+static void arm_trbe_probe_cpu(void *info)
+{
+	struct trbe_drvdata *drvdata = info;
+	int cpu = smp_processor_id();
+	struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
+	u64 trbidr;
+
+	if (WARN_ON(!cpudata))
+		goto cpu_clear;
+
+	if (!is_trbe_available()) {
+		pr_err("TRBE is not implemented on cpu %d\n", cpu);
+		goto cpu_clear;
+	}
+
+	trbidr = read_sysreg_s(SYS_TRBIDR_EL1);
+	if (!is_trbe_programmable(trbidr)) {
+		pr_err("TRBE is owned in higher exception level on cpu %d\n", cpu);
+		goto cpu_clear;
+	}
+
+	cpudata->trbe_align = 1ULL << get_trbe_address_align(trbidr);
+	if (cpudata->trbe_align > SZ_2K) {
+		pr_err("Unsupported alignment on cpu %d\n", cpu);
+		goto cpu_clear;
+	}
+	cpudata->trbe_flag = get_trbe_flag_update(trbidr);
+	cpudata->cpu = cpu;
+	cpudata->drvdata = drvdata;
+	return;
+cpu_clear:
+	cpumask_clear_cpu(cpu, &drvdata->supported_cpus);
+}
+
+static void arm_trbe_remove_coresight_cpu(void *info)
+{
+	int cpu = smp_processor_id();
+	struct trbe_drvdata *drvdata = info;
+	struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
+	struct coresight_device *trbe_csdev = coresight_get_percpu_sink(cpu);
+
+	disable_percpu_irq(drvdata->irq);
+	trbe_reset_local();
+	if (trbe_csdev) {
+		coresight_unregister(trbe_csdev);
+		cpudata->drvdata = NULL;
+		coresight_set_percpu_sink(cpu, NULL);
+	}
+}
+
+static int arm_trbe_probe_coresight(struct trbe_drvdata *drvdata)
+{
+	int cpu;
+
+	drvdata->cpudata = alloc_percpu(typeof(*drvdata->cpudata));
+	if (!drvdata->cpudata)
+		return -ENOMEM;
+
+	for_each_cpu(cpu, &drvdata->supported_cpus) {
+		smp_call_function_single(cpu, arm_trbe_probe_cpu, drvdata, 1);
+		if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
+			arm_trbe_register_coresight_cpu(drvdata, cpu);
+		if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
+			smp_call_function_single(cpu, arm_trbe_enable_cpu, drvdata, 1);
+	}
+	return 0;
+}
+
+static int arm_trbe_remove_coresight(struct trbe_drvdata *drvdata)
+{
+	int cpu;
+
+	for_each_cpu(cpu, &drvdata->supported_cpus)
+		smp_call_function_single(cpu, arm_trbe_remove_coresight_cpu, drvdata, 1);
+	free_percpu(drvdata->cpudata);
+	return 0;
+}
+
+static int arm_trbe_cpu_startup(unsigned int cpu, struct hlist_node *node)
+{
+	struct trbe_drvdata *drvdata = hlist_entry_safe(node, struct trbe_drvdata, hotplug_node);
+
+	if (cpumask_test_cpu(cpu, &drvdata->supported_cpus)) {
+
+		/*
+		 * If this CPU was not probed for TRBE,
+		 * initialize it now.
+		 */
+		if (!coresight_get_percpu_sink(cpu)) {
+			arm_trbe_probe_cpu(drvdata);
+			if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
+				arm_trbe_register_coresight_cpu(drvdata, cpu);
+			if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
+				arm_trbe_enable_cpu(drvdata);
+		} else {
+			arm_trbe_enable_cpu(drvdata);
+		}
+	}
+	return 0;
+}
+
+static int arm_trbe_cpu_teardown(unsigned int cpu, struct hlist_node *node)
+{
+	struct trbe_drvdata *drvdata = hlist_entry_safe(node, struct trbe_drvdata, hotplug_node);
+
+	if (cpumask_test_cpu(cpu, &drvdata->supported_cpus)) {
+		disable_percpu_irq(drvdata->irq);
+		trbe_reset_local();
+	}
+	return 0;
+}
+
+static int arm_trbe_probe_cpuhp(struct trbe_drvdata *drvdata)
+{
+	enum cpuhp_state trbe_online;
+	int ret;
+
+	trbe_online = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, DRVNAME,
+					      arm_trbe_cpu_startup, arm_trbe_cpu_teardown);
+	if (trbe_online < 0)
+		return trbe_online;
+
+	ret = cpuhp_state_add_instance(trbe_online, &drvdata->hotplug_node);
+	if (ret) {
+		cpuhp_remove_multi_state(trbe_online);
+		return ret;
+	}
+	drvdata->trbe_online = trbe_online;
+	return 0;
+}
+
+static void arm_trbe_remove_cpuhp(struct trbe_drvdata *drvdata)
+{
+	cpuhp_remove_multi_state(drvdata->trbe_online);
+}
+
+static int arm_trbe_probe_irq(struct platform_device *pdev,
+			      struct trbe_drvdata *drvdata)
+{
+	int ret;
+
+	drvdata->irq = platform_get_irq(pdev, 0);
+	if (drvdata->irq < 0) {
+		pr_err("IRQ not found for the platform device\n");
+		return drvdata->irq;
+	}
+
+	if (!irq_is_percpu(drvdata->irq)) {
+		pr_err("IRQ is not a PPI\n");
+		return -EINVAL;
+	}
+
+	if (irq_get_percpu_devid_partition(drvdata->irq, &drvdata->supported_cpus))
+		return -EINVAL;
+
+	drvdata->handle = alloc_percpu(struct perf_output_handle *);
+	if (!drvdata->handle)
+		return -ENOMEM;
+
+	ret = request_percpu_irq(drvdata->irq, arm_trbe_irq_handler, DRVNAME, drvdata->handle);
+	if (ret) {
+		free_percpu(drvdata->handle);
+		return ret;
+	}
+	return 0;
+}
+
+static void arm_trbe_remove_irq(struct trbe_drvdata *drvdata)
+{
+	free_percpu_irq(drvdata->irq, drvdata->handle);
+	free_percpu(drvdata->handle);
+}
+
+static int arm_trbe_device_probe(struct platform_device *pdev)
+{
+	struct coresight_platform_data *pdata;
+	struct trbe_drvdata *drvdata;
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
+	if (!drvdata)
+		return -ENOMEM;
+
+	pdata = coresight_get_platform_data(dev);
+	if (IS_ERR(pdata))
+		return PTR_ERR(pdata);
+
+	dev_set_drvdata(dev, drvdata);
+	dev->platform_data = pdata;
+	drvdata->pdev = pdev;
+	ret = arm_trbe_probe_irq(pdev, drvdata);
+	if (ret)
+		return ret;
+
+	ret = arm_trbe_probe_coresight(drvdata);
+	if (ret)
+		goto probe_failed;
+
+	ret = arm_trbe_probe_cpuhp(drvdata);
+	if (ret)
+		goto cpuhp_failed;
+
+	return 0;
+cpuhp_failed:
+	arm_trbe_remove_coresight(drvdata);
+probe_failed:
+	arm_trbe_remove_irq(drvdata);
+	return ret;
+}
+
+static int arm_trbe_device_remove(struct platform_device *pdev)
+{
+	struct trbe_drvdata *drvdata = platform_get_drvdata(pdev);
+
+	arm_trbe_remove_cpuhp(drvdata);
+	arm_trbe_remove_coresight(drvdata);
+	arm_trbe_remove_irq(drvdata);
+	return 0;
+}
+
+static const struct of_device_id arm_trbe_of_match[] = {
+	{ .compatible = "arm,trace-buffer-extension"},
+	{},
+};
+MODULE_DEVICE_TABLE(of, arm_trbe_of_match);
+
+static struct platform_driver arm_trbe_driver = {
+	.driver	= {
+		.name = DRVNAME,
+		.of_match_table = of_match_ptr(arm_trbe_of_match),
+		.suppress_bind_attrs = true,
+	},
+	.probe	= arm_trbe_device_probe,
+	.remove	= arm_trbe_device_remove,
+};
+
+static int __init arm_trbe_init(void)
+{
+	int ret;
+
+	if (arm64_kernel_unmapped_at_el0()) {
+		pr_err("TRBE wouldn't work if kernel gets unmapped at EL0\n");
+		return -EOPNOTSUPP;
+	}
+
+	ret = platform_driver_register(&arm_trbe_driver);
+	if (!ret)
+		return 0;
+
+	pr_err("Error registering %s platform driver\n", DRVNAME);
+	return ret;
+}
+
+static void __exit arm_trbe_exit(void)
+{
+	platform_driver_unregister(&arm_trbe_driver);
+}
+module_init(arm_trbe_init);
+module_exit(arm_trbe_exit);
+
+MODULE_AUTHOR("Anshuman Khandual <anshuman.khandual@arm.com>");
+MODULE_DESCRIPTION("Arm Trace Buffer Extension (TRBE) driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/hwtracing/coresight/coresight-trbe.h b/drivers/hwtracing/coresight/coresight-trbe.h
new file mode 100644
index 000000000000..abf3e36082f0
--- /dev/null
+++ b/drivers/hwtracing/coresight/coresight-trbe.h
@@ -0,0 +1,152 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * This contains all required hardware related helper functions for
+ * Trace Buffer Extension (TRBE) driver in the coresight framework.
+ *
+ * Copyright (C) 2020 ARM Ltd.
+ *
+ * Author: Anshuman Khandual <anshuman.khandual@arm.com>
+ */
+#include <linux/coresight.h>
+#include <linux/device.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/smp.h>
+
+#include "coresight-etm-perf.h"
+
+static inline bool is_trbe_available(void)
+{
+	u64 aa64dfr0 = read_sysreg_s(SYS_ID_AA64DFR0_EL1);
+	unsigned int trbe = cpuid_feature_extract_unsigned_field(aa64dfr0, ID_AA64DFR0_TRBE_SHIFT);
+
+	return trbe >= 0b0001;
+}
+
+static inline bool is_trbe_enabled(void)
+{
+	u64 trblimitr = read_sysreg_s(SYS_TRBLIMITR_EL1);
+
+	return trblimitr & TRBLIMITR_ENABLE;
+}
+
+#define TRBE_EC_OTHERS		0
+#define TRBE_EC_STAGE1_ABORT	36
+#define TRBE_EC_STAGE2_ABORT	37
+
+static inline int get_trbe_ec(u64 trbsr)
+{
+	return (trbsr >> TRBSR_EC_SHIFT) & TRBSR_EC_MASK;
+}
+
+#define TRBE_BSC_NOT_STOPPED 0
+#define TRBE_BSC_FILLED      1
+#define TRBE_BSC_TRIGGERED   2
+
+static inline int get_trbe_bsc(u64 trbsr)
+{
+	return (trbsr >> TRBSR_BSC_SHIFT) & TRBSR_BSC_MASK;
+}
+
+static inline void clr_trbe_irq(void)
+{
+	u64 trbsr = read_sysreg_s(SYS_TRBSR_EL1);
+
+	trbsr &= ~TRBSR_IRQ;
+	write_sysreg_s(trbsr, SYS_TRBSR_EL1);
+}
+
+static inline bool is_trbe_irq(u64 trbsr)
+{
+	return trbsr & TRBSR_IRQ;
+}
+
+static inline bool is_trbe_trg(u64 trbsr)
+{
+	return trbsr & TRBSR_TRG;
+}
+
+static inline bool is_trbe_wrap(u64 trbsr)
+{
+	return trbsr & TRBSR_WRAP;
+}
+
+static inline bool is_trbe_abort(u64 trbsr)
+{
+	return trbsr & TRBSR_ABORT;
+}
+
+static inline bool is_trbe_running(u64 trbsr)
+{
+	return !(trbsr & TRBSR_STOP);
+}
+
+#define TRBE_TRIG_MODE_STOP		0
+#define TRBE_TRIG_MODE_IRQ		1
+#define TRBE_TRIG_MODE_IGNORE		3
+
+#define TRBE_FILL_MODE_FILL		0
+#define TRBE_FILL_MODE_WRAP		1
+#define TRBE_FILL_MODE_CIRCULAR_BUFFER	3
+
+static inline void set_trbe_disabled(void)
+{
+	u64 trblimitr = read_sysreg_s(SYS_TRBLIMITR_EL1);
+
+	trblimitr &= ~TRBLIMITR_ENABLE;
+	write_sysreg_s(trblimitr, SYS_TRBLIMITR_EL1);
+}
+
+static inline bool get_trbe_flag_update(u64 trbidr)
+{
+	return trbidr & TRBIDR_FLAG;
+}
+
+static inline bool is_trbe_programmable(u64 trbidr)
+{
+	return !(trbidr & TRBIDR_PROG);
+}
+
+static inline int get_trbe_address_align(u64 trbidr)
+{
+	return (trbidr >> TRBIDR_ALIGN_SHIFT) & TRBIDR_ALIGN_MASK;
+}
+
+static inline unsigned long get_trbe_write_pointer(void)
+{
+	return read_sysreg_s(SYS_TRBPTR_EL1);
+}
+
+static inline void set_trbe_write_pointer(unsigned long addr)
+{
+	WARN_ON(is_trbe_enabled());
+	write_sysreg_s(addr, SYS_TRBPTR_EL1);
+}
+
+static inline unsigned long get_trbe_limit_pointer(void)
+{
+	u64 trblimitr = read_sysreg_s(SYS_TRBLIMITR_EL1);
+	unsigned long addr = trblimitr & (TRBLIMITR_LIMIT_MASK << TRBLIMITR_LIMIT_SHIFT);
+
+	WARN_ON(!IS_ALIGNED(addr, PAGE_SIZE));
+	return addr;
+}
+
+static inline unsigned long get_trbe_base_pointer(void)
+{
+	u64 trbbaser = read_sysreg_s(SYS_TRBBASER_EL1);
+	unsigned long addr = trbbaser & (TRBBASER_BASE_MASK << TRBBASER_BASE_SHIFT);
+
+	WARN_ON(!IS_ALIGNED(addr, PAGE_SIZE));
+	return addr;
+}
+
+static inline void set_trbe_base_pointer(unsigned long addr)
+{
+	WARN_ON(is_trbe_enabled());
+	WARN_ON(!IS_ALIGNED(addr, (1UL << TRBBASER_BASE_SHIFT)));
+	WARN_ON(!IS_ALIGNED(addr, PAGE_SIZE));
+	write_sysreg_s(addr, SYS_TRBBASER_EL1);
+}