Merge tag 'char-misc-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char/misc and other driver updates from Greg KH:
 "Here is the big set of char/misc and other small driver subsystem
  updates for 5.18-rc1.

  Included in here are merges from driver subsystems which contain:

   - iio driver updates and new drivers

   - fsi driver updates

   - fpga driver updates

   - habanalabs driver updates and support for new hardware

   - soundwire driver updates and new drivers

   - phy driver updates and new drivers

   - coresight driver updates

   - icc driver updates

  Individual changes include:

   - mei driver updates

   - interconnect driver updates

   - new PECI driver subsystem added

   - vmci driver updates

   - lots of tiny misc/char driver updates

  All of these have been in linux-next for a while with no reported
  problems"

* tag 'char-misc-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (556 commits)
  firmware: google: Properly state IOMEM dependency
  kgdbts: fix return value of __setup handler
  firmware: sysfb: fix platform-device leak in error path
  firmware: stratix10-svc: add missing callback parameter on RSU
  arm64: dts: qcom: add non-secure domain property to fastrpc nodes
  misc: fastrpc: Add dma handle implementation
  misc: fastrpc: Add fdlist implementation
  misc: fastrpc: Add helper function to get list and page
  misc: fastrpc: Add support to secure memory map
  dt-bindings: misc: add fastrpc domain vmid property
  misc: fastrpc: check before loading process to the DSP
  misc: fastrpc: add secure domain support
  dt-bindings: misc: add property to support non-secure DSP
  misc: fastrpc: Add support to get DSP capabilities
  misc: fastrpc: add support for FASTRPC_IOCTL_MEM_MAP/UNMAP
  misc: fastrpc: separate fastrpc device from channel context
  dt-bindings: nvmem: brcm,nvram: add basic NVMEM cells
  dt-bindings: nvmem: make "reg" property optional
  nvmem: brcm_nvram: parse NVRAM content into NVMEM cells
  nvmem: dt-bindings: Fix the error of dt-bindings check
  ...

8 files changed, 146 insertions, 54 deletions

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 88653d1c06a4..af00dca8d1ac 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -1279,9 +1279,6 @@ ATTRIBUTE_GROUPS(coresight_source);
 
 static struct device_type coresight_dev_type[] = {
 	{
-		.name = "none",
-	},
-	{
 		.name = "sink",
 		.groups = coresight_sink_groups,
 	},
diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c
index cf64ce73a741..7d413ba8b823 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
@@ -340,6 +340,10 @@ static int etm_parse_event_config(struct etm_drvdata *drvdata,
 
 	config->ctrl = attr->config;
 
+	/* Don't trace contextID when runs in non-root PID namespace */
+	if (!task_is_in_init_pid_ns(current))
+		config->ctrl &= ~ETMCR_CTXID_SIZE;
+
 	/*
 	 * Possible to have cores with PTM (supports ret stack) and ETM
 	 * (never has ret stack) on the same SoC. So if we have a request
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index bf18128cf5de..7f416a12000e 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -656,7 +656,9 @@ static int etm4_parse_event_config(struct coresight_device *csdev,
 		config->cfg |= BIT(11);
 	}
 
-	if (attr->config & BIT(ETM_OPT_CTXTID))
+	/* Only trace contextID when runs in root PID namespace */
+	if ((attr->config & BIT(ETM_OPT_CTXTID)) &&
+	    task_is_in_init_pid_ns(current))
 		/* bit[6], Context ID tracing bit */
 		config->cfg |= BIT(ETM4_CFG_BIT_CTXTID);
 
@@ -670,7 +672,11 @@ static int etm4_parse_event_config(struct coresight_device *csdev,
 			ret = -EINVAL;
 			goto out;
 		}
-		config->cfg |= BIT(ETM4_CFG_BIT_VMID) | BIT(ETM4_CFG_BIT_VMID_OPT);
+
+		/* Only trace virtual contextID when runs in root PID namespace */
+		if (task_is_in_init_pid_ns(current))
+			config->cfg |= BIT(ETM4_CFG_BIT_VMID) |
+				       BIT(ETM4_CFG_BIT_VMID_OPT);
 	}
 
 	/* return stack - enable if selected and supported */
@@ -1091,7 +1097,7 @@ static void etm4_init_arch_data(void *info)
 	etmidr0 = etm4x_relaxed_read32(csa, TRCIDR0);
 
 	/* INSTP0, bits[2:1] P0 tracing support field */
-	if (BMVAL(etmidr0, 1, 1) && BMVAL(etmidr0, 2, 2))
+	if (BMVAL(etmidr0, 1, 2) == 0b11)
 		drvdata->instrp0 = true;
 	else
 		drvdata->instrp0 = false;
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
index a0640fa5c55b..21687cc1e4e2 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
@@ -367,8 +367,12 @@ static ssize_t mode_store(struct device *dev,
 	mode = ETM_MODE_QELEM(config->mode);
 	/* start by clearing QE bits */
 	config->cfg &= ~(BIT(13) | BIT(14));
-	/* if supported, Q elements with instruction counts are enabled */
-	if ((mode & BIT(0)) && (drvdata->q_support & BIT(0)))
+	/*
+	 * if supported, Q elements with instruction counts are enabled.
+	 * Always set the low bit for any requested mode. Valid combos are
+	 * 0b00, 0b01 and 0b11.
+	 */
+	if (mode && drvdata->q_support)
 		config->cfg |= BIT(13);
 	/*
 	 * if supported, Q elements with and without instruction
@@ -2111,7 +2115,16 @@ static ssize_t vmid_val_show(struct device *dev,
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
 	struct etmv4_config *config = &drvdata->config;
 
+	/*
+	 * Don't use virtual contextID tracing if coming from a PID namespace.
+	 * See comment in ctxid_pid_store().
+	 */
+	if (!task_is_in_init_pid_ns(current))
+		return -EINVAL;
+
+	spin_lock(&drvdata->spinlock);
 	val = (unsigned long)config->vmid_val[config->vmid_idx];
+	spin_unlock(&drvdata->spinlock);
 	return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
 }
 
@@ -2124,6 +2137,13 @@ static ssize_t vmid_val_store(struct device *dev,
 	struct etmv4_config *config = &drvdata->config;
 
 	/*
+	 * Don't use virtual contextID tracing if coming from a PID namespace.
+	 * See comment in ctxid_pid_store().
+	 */
+	if (!task_is_in_init_pid_ns(current))
+		return -EINVAL;
+
+	/*
 	 * only implemented when vmid tracing is enabled, i.e. at least one
 	 * vmid comparator is implemented and at least 8 bit vmid size
 	 */
@@ -2146,6 +2166,13 @@ static ssize_t vmid_masks_show(struct device *dev,
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
 	struct etmv4_config *config = &drvdata->config;
 
+	/*
+	 * Don't use virtual contextID tracing if coming from a PID namespace.
+	 * See comment in ctxid_pid_store().
+	 */
+	if (!task_is_in_init_pid_ns(current))
+		return -EINVAL;
+
 	spin_lock(&drvdata->spinlock);
 	val1 = config->vmid_mask0;
 	val2 = config->vmid_mask1;
@@ -2164,6 +2191,13 @@ static ssize_t vmid_masks_store(struct device *dev,
 	int nr_inputs;
 
 	/*
+	 * Don't use virtual contextID tracing if coming from a PID namespace.
+	 * See comment in ctxid_pid_store().
+	 */
+	if (!task_is_in_init_pid_ns(current))
+		return -EINVAL;
+
+	/*
 	 * only implemented when vmid tracing is enabled, i.e. at least one
 	 * vmid comparator is implemented and at least 8 bit vmid size
 	 */
diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c
index c594f45319fc..475899714104 100644
--- a/drivers/hwtracing/coresight/coresight-platform.c
+++ b/drivers/hwtracing/coresight/coresight-platform.c
@@ -626,7 +626,7 @@ static int acpi_coresight_parse_link(struct acpi_device *adev,
 				     const union acpi_object *link,
 				     struct coresight_connection *conn)
 {
-	int rc, dir;
+	int dir;
 	const union acpi_object *fields;
 	struct acpi_device *r_adev;
 	struct device *rdev;
@@ -643,9 +643,9 @@ static int acpi_coresight_parse_link(struct acpi_device *adev,
 	    fields[3].type != ACPI_TYPE_INTEGER)
 		return -EINVAL;
 
-	rc = acpi_bus_get_device(fields[2].reference.handle, &r_adev);
-	if (rc)
-		return rc;
+	r_adev = acpi_fetch_acpi_dev(fields[2].reference.handle);
+	if (!r_adev)
+		return -ENODEV;
 
 	dir = fields[3].integer.value;
 	if (dir == ACPI_CORESIGHT_LINK_MASTER) {
diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
index 098fc34c4829..11850fd8c3b5 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg.c
+++ b/drivers/hwtracing/coresight/coresight-syscfg.c
@@ -1049,7 +1049,7 @@ static int cscfg_create_device(void)
 
 	err = device_register(dev);
 	if (err)
-		cscfg_dev_release(dev);
+		put_device(dev);
 
 create_dev_exit_unlock:
 	mutex_unlock(&cscfg_mutex);
diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
index 276862c07e32..2b386bb848f8 100644
--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -91,10 +91,16 @@ struct trbe_buf {
  */
 #define TRBE_WORKAROUND_OVERWRITE_FILL_MODE	0
 #define TRBE_WORKAROUND_WRITE_OUT_OF_RANGE	1
+#define TRBE_NEEDS_DRAIN_AFTER_DISABLE		2
+#define TRBE_NEEDS_CTXT_SYNC_AFTER_ENABLE	3
+#define TRBE_IS_BROKEN				4
 
 static int trbe_errata_cpucaps[] = {
 	[TRBE_WORKAROUND_OVERWRITE_FILL_MODE] = ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE,
 	[TRBE_WORKAROUND_WRITE_OUT_OF_RANGE] = ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE,
+	[TRBE_NEEDS_DRAIN_AFTER_DISABLE] = ARM64_WORKAROUND_2064142,
+	[TRBE_NEEDS_CTXT_SYNC_AFTER_ENABLE] = ARM64_WORKAROUND_2038923,
+	[TRBE_IS_BROKEN] = ARM64_WORKAROUND_1902691,
 	-1,		/* Sentinel, must be the last entry */
 };
 
@@ -167,6 +173,32 @@ static inline bool trbe_may_write_out_of_range(struct trbe_cpudata *cpudata)
 	return trbe_has_erratum(cpudata, TRBE_WORKAROUND_WRITE_OUT_OF_RANGE);
 }
 
+static inline bool trbe_needs_drain_after_disable(struct trbe_cpudata *cpudata)
+{
+	/*
+	 * Errata affected TRBE implementation will need TSB CSYNC and
+	 * DSB in order to prevent subsequent writes into certain TRBE
+	 * system registers from being ignored and not effected.
+	 */
+	return trbe_has_erratum(cpudata, TRBE_NEEDS_DRAIN_AFTER_DISABLE);
+}
+
+static inline bool trbe_needs_ctxt_sync_after_enable(struct trbe_cpudata *cpudata)
+{
+	/*
+	 * Errata affected TRBE implementation will need an additional
+	 * context synchronization in order to prevent an inconsistent
+	 * TRBE prohibited region view on the CPU which could possibly
+	 * corrupt the TRBE buffer or the TRBE state.
+	 */
+	return trbe_has_erratum(cpudata, TRBE_NEEDS_CTXT_SYNC_AFTER_ENABLE);
+}
+
+static inline bool trbe_is_broken(struct trbe_cpudata *cpudata)
+{
+	return trbe_has_erratum(cpudata, TRBE_IS_BROKEN);
+}
+
 static int trbe_alloc_node(struct perf_event *event)
 {
 	if (event->cpu == -1)
@@ -174,17 +206,31 @@ static int trbe_alloc_node(struct perf_event *event)
 	return cpu_to_node(event->cpu);
 }
 
-static void trbe_drain_buffer(void)
+static inline void trbe_drain_buffer(void)
 {
 	tsb_csync();
 	dsb(nsh);
 }
 
-static void trbe_drain_and_disable_local(void)
+static inline void set_trbe_enabled(struct trbe_cpudata *cpudata, u64 trblimitr)
 {
-	u64 trblimitr = read_sysreg_s(SYS_TRBLIMITR_EL1);
+	/*
+	 * Enable the TRBE without clearing LIMITPTR which
+	 * might be required for fetching the buffer limits.
+	 */
+	trblimitr |= TRBLIMITR_ENABLE;
+	write_sysreg_s(trblimitr, SYS_TRBLIMITR_EL1);
 
-	trbe_drain_buffer();
+	/* Synchronize the TRBE enable event */
+	isb();
+
+	if (trbe_needs_ctxt_sync_after_enable(cpudata))
+		isb();
+}
+
+static inline void set_trbe_disabled(struct trbe_cpudata *cpudata)
+{
+	u64 trblimitr = read_sysreg_s(SYS_TRBLIMITR_EL1);
 
 	/*
 	 * Disable the TRBE without clearing LIMITPTR which
@@ -192,12 +238,21 @@ static void trbe_drain_and_disable_local(void)
 	 */
 	trblimitr &= ~TRBLIMITR_ENABLE;
 	write_sysreg_s(trblimitr, SYS_TRBLIMITR_EL1);
+
+	if (trbe_needs_drain_after_disable(cpudata))
+		trbe_drain_buffer();
 	isb();
 }
 
-static void trbe_reset_local(void)
+static void trbe_drain_and_disable_local(struct trbe_cpudata *cpudata)
 {
-	trbe_drain_and_disable_local();
+	trbe_drain_buffer();
+	set_trbe_disabled(cpudata);
+}
+
+static void trbe_reset_local(struct trbe_cpudata *cpudata)
+{
+	trbe_drain_and_disable_local(cpudata);
 	write_sysreg_s(0, SYS_TRBLIMITR_EL1);
 	write_sysreg_s(0, SYS_TRBPTR_EL1);
 	write_sysreg_s(0, SYS_TRBBASER_EL1);
@@ -234,7 +289,7 @@ static void trbe_stop_and_truncate_event(struct perf_output_handle *handle)
 	 * at event_stop(). So disable the TRBE here and leave
 	 * the update_buffer() to return a 0 size.
 	 */
-	trbe_drain_and_disable_local();
+	trbe_drain_and_disable_local(buf->cpudata);
 	perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
 	perf_aux_output_end(handle, 0);
 	*this_cpu_ptr(buf->cpudata->drvdata->handle) = NULL;
@@ -536,9 +591,10 @@ static void clr_trbe_status(void)
 	write_sysreg_s(trbsr, SYS_TRBSR_EL1);
 }
 
-static void set_trbe_limit_pointer_enabled(unsigned long addr)
+static void set_trbe_limit_pointer_enabled(struct trbe_buf *buf)
 {
 	u64 trblimitr = read_sysreg_s(SYS_TRBLIMITR_EL1);
+	unsigned long addr = buf->trbe_limit;
 
 	WARN_ON(!IS_ALIGNED(addr, (1UL << TRBLIMITR_LIMIT_SHIFT)));
 	WARN_ON(!IS_ALIGNED(addr, PAGE_SIZE));
@@ -566,12 +622,7 @@ static void set_trbe_limit_pointer_enabled(unsigned long addr)
 	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();
+	set_trbe_enabled(buf->cpudata, trblimitr);
 }
 
 static void trbe_enable_hw(struct trbe_buf *buf)
@@ -579,8 +630,7 @@ static void trbe_enable_hw(struct trbe_buf *buf)
 	WARN_ON(buf->trbe_hw_base < buf->trbe_base);
 	WARN_ON(buf->trbe_write < buf->trbe_hw_base);
 	WARN_ON(buf->trbe_write >= buf->trbe_limit);
-	set_trbe_disabled();
-	isb();
+	set_trbe_disabled(buf->cpudata);
 	clr_trbe_status();
 	set_trbe_base_pointer(buf->trbe_hw_base);
 	set_trbe_write_pointer(buf->trbe_write);
@@ -590,7 +640,7 @@ static void trbe_enable_hw(struct trbe_buf *buf)
 	 * till now before enabling the TRBE.
 	 */
 	isb();
-	set_trbe_limit_pointer_enabled(buf->trbe_limit);
+	set_trbe_limit_pointer_enabled(buf);
 }
 
 static enum trbe_fault_action trbe_get_fault_act(struct perf_output_handle *handle,
@@ -775,7 +825,7 @@ static unsigned long arm_trbe_update_buffer(struct coresight_device *csdev,
 	 * 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();
+	trbe_drain_and_disable_local(cpudata);
 
 	/* Check if there is a pending interrupt and handle it here */
 	status = read_sysreg_s(SYS_TRBSR_EL1);
@@ -986,7 +1036,7 @@ static int arm_trbe_disable(struct coresight_device *csdev)
 	if (cpudata->mode != CS_MODE_PERF)
 		return -EINVAL;
 
-	trbe_drain_and_disable_local();
+	trbe_drain_and_disable_local(cpudata);
 	buf->cpudata = NULL;
 	cpudata->buf = NULL;
 	cpudata->mode = CS_MODE_DISABLED;
@@ -995,16 +1045,15 @@ static int arm_trbe_disable(struct coresight_device *csdev)
 
 static void trbe_handle_spurious(struct perf_output_handle *handle)
 {
-	u64 limitr = read_sysreg_s(SYS_TRBLIMITR_EL1);
+	struct trbe_buf *buf = etm_perf_sink_config(handle);
+	u64 trblimitr = read_sysreg_s(SYS_TRBLIMITR_EL1);
 
 	/*
 	 * If the IRQ was spurious, simply re-enable the TRBE
 	 * back without modifying the buffer parameters to
 	 * retain the trace collected so far.
 	 */
-	limitr |= TRBLIMITR_ENABLE;
-	write_sysreg_s(limitr, SYS_TRBLIMITR_EL1);
-	isb();
+	set_trbe_enabled(buf->cpudata, trblimitr);
 }
 
 static int trbe_handle_overflow(struct perf_output_handle *handle)
@@ -1028,7 +1077,7 @@ static int trbe_handle_overflow(struct perf_output_handle *handle)
 		 * is able to detect this with a disconnected handle
 		 * (handle->event = NULL).
 		 */
-		trbe_drain_and_disable_local();
+		trbe_drain_and_disable_local(buf->cpudata);
 		*this_cpu_ptr(buf->cpudata->drvdata->handle) = NULL;
 		return -EINVAL;
 	}
@@ -1062,6 +1111,7 @@ 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;
+	struct trbe_buf *buf = etm_perf_sink_config(handle);
 	enum trbe_fault_action act;
 	u64 status;
 	bool truncated = false;
@@ -1082,7 +1132,7 @@ static irqreturn_t arm_trbe_irq_handler(int irq, void *dev)
 	 * Ensure the trace is visible to the CPUs and
 	 * any external aborts have been resolved.
 	 */
-	trbe_drain_and_disable_local();
+	trbe_drain_and_disable_local(buf->cpudata);
 	clr_trbe_irq();
 	isb();
 
@@ -1167,8 +1217,9 @@ static const struct attribute_group *arm_trbe_groups[] = {
 static void arm_trbe_enable_cpu(void *info)
 {
 	struct trbe_drvdata *drvdata = info;
+	struct trbe_cpudata *cpudata = this_cpu_ptr(drvdata->cpudata);
 
-	trbe_reset_local();
+	trbe_reset_local(cpudata);
 	enable_percpu_irq(drvdata->irq, IRQ_TYPE_NONE);
 }
 
@@ -1244,6 +1295,11 @@ static void arm_trbe_probe_cpu(void *info)
 	 */
 	trbe_check_errata(cpudata);
 
+	if (trbe_is_broken(cpudata)) {
+		pr_err("Disabling TRBE on cpu%d due to erratum\n", cpu);
+		goto cpu_clear;
+	}
+
 	/*
 	 * If the TRBE is affected by erratum TRBE_WORKAROUND_OVERWRITE_FILL_MODE,
 	 * we must always program the TBRPTR_EL1, 256bytes from a page
@@ -1276,7 +1332,7 @@ static void arm_trbe_remove_coresight_cpu(void *info)
 	struct coresight_device *trbe_csdev = coresight_get_percpu_sink(cpu);
 
 	disable_percpu_irq(drvdata->irq);
-	trbe_reset_local();
+	trbe_reset_local(cpudata);
 	if (trbe_csdev) {
 		coresight_unregister(trbe_csdev);
 		cpudata->drvdata = NULL;
@@ -1349,8 +1405,10 @@ 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)) {
+		struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
+
 		disable_percpu_irq(drvdata->irq);
-		trbe_reset_local();
+		trbe_reset_local(cpudata);
 	}
 	return 0;
 }
@@ -1423,6 +1481,12 @@ static int arm_trbe_device_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	int ret;
 
+	/* Trace capture is not possible with kernel page table isolation */
+	if (arm64_kernel_unmapped_at_el0()) {
+		pr_err("TRBE wouldn't work if kernel gets unmapped at EL0\n");
+		return -EOPNOTSUPP;
+	}
+
 	drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
 	if (!drvdata)
 		return -ENOMEM;
@@ -1484,11 +1548,6 @@ 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;
diff --git a/drivers/hwtracing/coresight/coresight-trbe.h b/drivers/hwtracing/coresight/coresight-trbe.h
index abf3e36082f0..30e4d7db4f8e 100644
--- a/drivers/hwtracing/coresight/coresight-trbe.h
+++ b/drivers/hwtracing/coresight/coresight-trbe.h
@@ -91,14 +91,6 @@ static inline bool is_trbe_running(u64 trbsr)
 #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;