Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 1143 insertions, 0 deletions

diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c
new file mode 100644
index 000000000..e8dd2f0f3
--- /dev/null
+++ b/drivers/firmware/arm_sdei.c
@@ -0,0 +1,1143 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2017 Arm Ltd.
+#define pr_fmt(fmt) "sdei: " fmt
+
+#include <acpi/ghes.h>
+#include <linux/acpi.h>
+#include <linux/arm_sdei.h>
+#include <linux/arm-smccc.h>
+#include <linux/atomic.h>
+#include <linux/bitops.h>
+#include <linux/compiler.h>
+#include <linux/cpuhotplug.h>
+#include <linux/cpu.h>
+#include <linux/cpu_pm.h>
+#include <linux/errno.h>
+#include <linux/hardirq.h>
+#include <linux/kernel.h>
+#include <linux/kprobes.h>
+#include <linux/kvm_host.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/notifier.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/percpu.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/ptrace.h>
+#include <linux/preempt.h>
+#include <linux/reboot.h>
+#include <linux/slab.h>
+#include <linux/smp.h>
+#include <linux/spinlock.h>
+
+/*
+ * The call to use to reach the firmware.
+ */
+static asmlinkage void (*sdei_firmware_call)(unsigned long function_id,
+		      unsigned long arg0, unsigned long arg1,
+		      unsigned long arg2, unsigned long arg3,
+		      unsigned long arg4, struct arm_smccc_res *res);
+
+/* entry point from firmware to arch asm code */
+static unsigned long sdei_entry_point;
+
+static int sdei_hp_state;
+
+struct sdei_event {
+	/* These three are protected by the sdei_list_lock */
+	struct list_head	list;
+	bool			reregister;
+	bool			reenable;
+
+	u32			event_num;
+	u8			type;
+	u8			priority;
+
+	/* This pointer is handed to firmware as the event argument. */
+	union {
+		/* Shared events */
+		struct sdei_registered_event *registered;
+
+		/* CPU private events */
+		struct sdei_registered_event __percpu *private_registered;
+	};
+};
+
+/* Take the mutex for any API call or modification. Take the mutex first. */
+static DEFINE_MUTEX(sdei_events_lock);
+
+/* and then hold this when modifying the list */
+static DEFINE_SPINLOCK(sdei_list_lock);
+static LIST_HEAD(sdei_list);
+
+/* Private events are registered/enabled via IPI passing one of these */
+struct sdei_crosscall_args {
+	struct sdei_event *event;
+	atomic_t errors;
+	int first_error;
+};
+
+#define CROSSCALL_INIT(arg, event)		\
+	do {					\
+		arg.event = event;		\
+		arg.first_error = 0;		\
+		atomic_set(&arg.errors, 0);	\
+	} while (0)
+
+static inline int sdei_do_local_call(smp_call_func_t fn,
+				     struct sdei_event *event)
+{
+	struct sdei_crosscall_args arg;
+
+	CROSSCALL_INIT(arg, event);
+	fn(&arg);
+
+	return arg.first_error;
+}
+
+static inline int sdei_do_cross_call(smp_call_func_t fn,
+				     struct sdei_event *event)
+{
+	struct sdei_crosscall_args arg;
+
+	CROSSCALL_INIT(arg, event);
+	on_each_cpu(fn, &arg, true);
+
+	return arg.first_error;
+}
+
+static inline void
+sdei_cross_call_return(struct sdei_crosscall_args *arg, int err)
+{
+	if (err && (atomic_inc_return(&arg->errors) == 1))
+		arg->first_error = err;
+}
+
+static int sdei_to_linux_errno(unsigned long sdei_err)
+{
+	switch (sdei_err) {
+	case SDEI_NOT_SUPPORTED:
+		return -EOPNOTSUPP;
+	case SDEI_INVALID_PARAMETERS:
+		return -EINVAL;
+	case SDEI_DENIED:
+		return -EPERM;
+	case SDEI_PENDING:
+		return -EINPROGRESS;
+	case SDEI_OUT_OF_RESOURCE:
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static int invoke_sdei_fn(unsigned long function_id, unsigned long arg0,
+			  unsigned long arg1, unsigned long arg2,
+			  unsigned long arg3, unsigned long arg4,
+			  u64 *result)
+{
+	int err;
+	struct arm_smccc_res res;
+
+	if (sdei_firmware_call) {
+		sdei_firmware_call(function_id, arg0, arg1, arg2, arg3, arg4,
+				   &res);
+		err = sdei_to_linux_errno(res.a0);
+	} else {
+		/*
+		 * !sdei_firmware_call means we failed to probe or called
+		 * sdei_mark_interface_broken(). -EIO is not an error returned
+		 * by sdei_to_linux_errno() and is used to suppress messages
+		 * from this driver.
+		 */
+		err = -EIO;
+		res.a0 = SDEI_NOT_SUPPORTED;
+	}
+
+	if (result)
+		*result = res.a0;
+
+	return err;
+}
+NOKPROBE_SYMBOL(invoke_sdei_fn);
+
+static struct sdei_event *sdei_event_find(u32 event_num)
+{
+	struct sdei_event *e, *found = NULL;
+
+	lockdep_assert_held(&sdei_events_lock);
+
+	spin_lock(&sdei_list_lock);
+	list_for_each_entry(e, &sdei_list, list) {
+		if (e->event_num == event_num) {
+			found = e;
+			break;
+		}
+	}
+	spin_unlock(&sdei_list_lock);
+
+	return found;
+}
+
+int sdei_api_event_context(u32 query, u64 *result)
+{
+	return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_CONTEXT, query, 0, 0, 0, 0,
+			      result);
+}
+NOKPROBE_SYMBOL(sdei_api_event_context);
+
+static int sdei_api_event_get_info(u32 event, u32 info, u64 *result)
+{
+	return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_GET_INFO, event, info, 0,
+			      0, 0, result);
+}
+
+static struct sdei_event *sdei_event_create(u32 event_num,
+					    sdei_event_callback *cb,
+					    void *cb_arg)
+{
+	int err;
+	u64 result;
+	struct sdei_event *event;
+	struct sdei_registered_event *reg;
+
+	lockdep_assert_held(&sdei_events_lock);
+
+	event = kzalloc_obj(*event);
+	if (!event) {
+		err = -ENOMEM;
+		goto fail;
+	}
+
+	INIT_LIST_HEAD(&event->list);
+	event->event_num = event_num;
+
+	err = sdei_api_event_get_info(event_num, SDEI_EVENT_INFO_EV_PRIORITY,
+				      &result);
+	if (err)
+		goto fail;
+	event->priority = result;
+
+	err = sdei_api_event_get_info(event_num, SDEI_EVENT_INFO_EV_TYPE,
+				      &result);
+	if (err)
+		goto fail;
+	event->type = result;
+
+	if (event->type == SDEI_EVENT_TYPE_SHARED) {
+		reg = kzalloc_obj(*reg);
+		if (!reg) {
+			err = -ENOMEM;
+			goto fail;
+		}
+
+		reg->event_num = event->event_num;
+		reg->priority = event->priority;
+
+		reg->callback = cb;
+		reg->callback_arg = cb_arg;
+		event->registered = reg;
+	} else {
+		int cpu;
+		struct sdei_registered_event __percpu *regs;
+
+		regs = alloc_percpu(struct sdei_registered_event);
+		if (!regs) {
+			err = -ENOMEM;
+			goto fail;
+		}
+
+		for_each_possible_cpu(cpu) {
+			reg = per_cpu_ptr(regs, cpu);
+
+			reg->event_num = event->event_num;
+			reg->priority = event->priority;
+			reg->callback = cb;
+			reg->callback_arg = cb_arg;
+		}
+
+		event->private_registered = regs;
+	}
+
+	spin_lock(&sdei_list_lock);
+	list_add(&event->list, &sdei_list);
+	spin_unlock(&sdei_list_lock);
+
+	return event;
+
+fail:
+	kfree(event);
+	return ERR_PTR(err);
+}
+
+static void sdei_event_destroy_llocked(struct sdei_event *event)
+{
+	lockdep_assert_held(&sdei_events_lock);
+	lockdep_assert_held(&sdei_list_lock);
+
+	list_del(&event->list);
+
+	if (event->type == SDEI_EVENT_TYPE_SHARED)
+		kfree(event->registered);
+	else
+		free_percpu(event->private_registered);
+
+	kfree(event);
+}
+
+static void sdei_event_destroy(struct sdei_event *event)
+{
+	spin_lock(&sdei_list_lock);
+	sdei_event_destroy_llocked(event);
+	spin_unlock(&sdei_list_lock);
+}
+
+static int sdei_api_get_version(u64 *version)
+{
+	return invoke_sdei_fn(SDEI_1_0_FN_SDEI_VERSION, 0, 0, 0, 0, 0, version);
+}
+
+int sdei_mask_local_cpu(void)
+{
+	int err;
+
+	err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PE_MASK, 0, 0, 0, 0, 0, NULL);
+	if (err && err != -EIO) {
+		pr_warn_once("failed to mask CPU[%u]: %d\n",
+			      smp_processor_id(), err);
+		return err;
+	}
+
+	return 0;
+}
+
+static void _ipi_mask_cpu(void *ignored)
+{
+	WARN_ON_ONCE(preemptible());
+	sdei_mask_local_cpu();
+}
+
+int sdei_unmask_local_cpu(void)
+{
+	int err;
+
+	err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PE_UNMASK, 0, 0, 0, 0, 0, NULL);
+	if (err && err != -EIO) {
+		pr_warn_once("failed to unmask CPU[%u]: %d\n",
+			     smp_processor_id(), err);
+		return err;
+	}
+
+	return 0;
+}
+
+static void _ipi_unmask_cpu(void *ignored)
+{
+	WARN_ON_ONCE(preemptible());
+	sdei_unmask_local_cpu();
+}
+
+/*
+ * Signal the software-signalled event (event 0) to @mpidr. Does nothing
+ * but the SMC -- no locks, no event lookup -- so it is safe from NMI /
+ * crash context (e.g. the cross-CPU NMI service).
+ */
+int sdei_event_signal(u32 event_num, u64 mpidr)
+{
+	return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_SIGNAL, event_num,
+			      mpidr, 0, 0, 0, NULL);
+}
+NOKPROBE_SYMBOL(sdei_event_signal);
+
+/*
+ * Was SDEI firmware probed and is it usable?  Lets optional consumers skip
+ * registering an event -- and the warning a failed registration emits -- on
+ * systems with no SDEI.
+ */
+bool sdei_is_present(void)
+{
+	return sdei_firmware_call;
+}
+
+static void _ipi_private_reset(void *ignored)
+{
+	int err;
+
+	WARN_ON_ONCE(preemptible());
+
+	err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PRIVATE_RESET, 0, 0, 0, 0, 0,
+			     NULL);
+	if (err && err != -EIO)
+		pr_warn_once("failed to reset CPU[%u]: %d\n",
+			     smp_processor_id(), err);
+}
+
+static int sdei_api_shared_reset(void)
+{
+	return invoke_sdei_fn(SDEI_1_0_FN_SDEI_SHARED_RESET, 0, 0, 0, 0, 0,
+			      NULL);
+}
+
+static void sdei_mark_interface_broken(void)
+{
+	pr_err("disabling SDEI firmware interface\n");
+	on_each_cpu(&_ipi_mask_cpu, NULL, true);
+	sdei_firmware_call = NULL;
+}
+
+static int sdei_platform_reset(void)
+{
+	int err;
+
+	on_each_cpu(&_ipi_private_reset, NULL, true);
+	err = sdei_api_shared_reset();
+	if (err) {
+		pr_err("Failed to reset platform: %d\n", err);
+		sdei_mark_interface_broken();
+	}
+
+	return err;
+}
+
+static int sdei_api_event_enable(u32 event_num)
+{
+	return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_ENABLE, event_num, 0, 0, 0,
+			      0, NULL);
+}
+
+/* Called directly by the hotplug callbacks */
+static void _local_event_enable(void *data)
+{
+	int err;
+	struct sdei_crosscall_args *arg = data;
+
+	err = sdei_api_event_enable(arg->event->event_num);
+
+	sdei_cross_call_return(arg, err);
+}
+
+int sdei_event_enable(u32 event_num)
+{
+	int err = -EINVAL;
+	struct sdei_event *event;
+
+	mutex_lock(&sdei_events_lock);
+	event = sdei_event_find(event_num);
+	if (!event) {
+		mutex_unlock(&sdei_events_lock);
+		return -ENOENT;
+	}
+
+
+	cpus_read_lock();
+	if (event->type == SDEI_EVENT_TYPE_SHARED)
+		err = sdei_api_event_enable(event->event_num);
+	else
+		err = sdei_do_cross_call(_local_event_enable, event);
+
+	if (!err) {
+		spin_lock(&sdei_list_lock);
+		event->reenable = true;
+		spin_unlock(&sdei_list_lock);
+	}
+	cpus_read_unlock();
+	mutex_unlock(&sdei_events_lock);
+
+	return err;
+}
+
+static int sdei_api_event_disable(u32 event_num)
+{
+	return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_DISABLE, event_num, 0, 0,
+			      0, 0, NULL);
+}
+
+static void _ipi_event_disable(void *data)
+{
+	int err;
+	struct sdei_crosscall_args *arg = data;
+
+	err = sdei_api_event_disable(arg->event->event_num);
+
+	sdei_cross_call_return(arg, err);
+}
+
+int sdei_event_disable(u32 event_num)
+{
+	int err = -EINVAL;
+	struct sdei_event *event;
+
+	mutex_lock(&sdei_events_lock);
+	event = sdei_event_find(event_num);
+	if (!event) {
+		mutex_unlock(&sdei_events_lock);
+		return -ENOENT;
+	}
+
+	spin_lock(&sdei_list_lock);
+	event->reenable = false;
+	spin_unlock(&sdei_list_lock);
+
+	if (event->type == SDEI_EVENT_TYPE_SHARED)
+		err = sdei_api_event_disable(event->event_num);
+	else
+		err = sdei_do_cross_call(_ipi_event_disable, event);
+	mutex_unlock(&sdei_events_lock);
+
+	return err;
+}
+
+static int sdei_api_event_unregister(u32 event_num)
+{
+	return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_UNREGISTER, event_num, 0,
+			      0, 0, 0, NULL);
+}
+
+/* Called directly by the hotplug callbacks */
+static void _local_event_unregister(void *data)
+{
+	int err;
+	struct sdei_crosscall_args *arg = data;
+
+	err = sdei_api_event_unregister(arg->event->event_num);
+
+	sdei_cross_call_return(arg, err);
+}
+
+int sdei_event_unregister(u32 event_num)
+{
+	int err;
+	struct sdei_event *event;
+
+	WARN_ON(in_nmi());
+
+	mutex_lock(&sdei_events_lock);
+	event = sdei_event_find(event_num);
+	if (!event) {
+		pr_warn("Event %u not registered\n", event_num);
+		err = -ENOENT;
+		goto unlock;
+	}
+
+	spin_lock(&sdei_list_lock);
+	event->reregister = false;
+	event->reenable = false;
+	spin_unlock(&sdei_list_lock);
+
+	if (event->type == SDEI_EVENT_TYPE_SHARED)
+		err = sdei_api_event_unregister(event->event_num);
+	else
+		err = sdei_do_cross_call(_local_event_unregister, event);
+
+	if (err)
+		goto unlock;
+
+	sdei_event_destroy(event);
+unlock:
+	mutex_unlock(&sdei_events_lock);
+
+	return err;
+}
+
+/*
+ * unregister events, but don't destroy them as they are re-registered by
+ * sdei_reregister_shared().
+ */
+static int sdei_unregister_shared(void)
+{
+	int err = 0;
+	struct sdei_event *event;
+
+	mutex_lock(&sdei_events_lock);
+	spin_lock(&sdei_list_lock);
+	list_for_each_entry(event, &sdei_list, list) {
+		if (event->type != SDEI_EVENT_TYPE_SHARED)
+			continue;
+
+		err = sdei_api_event_unregister(event->event_num);
+		if (err)
+			break;
+	}
+	spin_unlock(&sdei_list_lock);
+	mutex_unlock(&sdei_events_lock);
+
+	return err;
+}
+
+static int sdei_api_event_register(u32 event_num, unsigned long entry_point,
+				   void *arg, u64 flags, u64 affinity)
+{
+	return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_REGISTER, event_num,
+			      (unsigned long)entry_point, (unsigned long)arg,
+			      flags, affinity, NULL);
+}
+
+/* Called directly by the hotplug callbacks */
+static void _local_event_register(void *data)
+{
+	int err;
+	struct sdei_registered_event *reg;
+	struct sdei_crosscall_args *arg = data;
+
+	reg = per_cpu_ptr(arg->event->private_registered, smp_processor_id());
+	err = sdei_api_event_register(arg->event->event_num, sdei_entry_point,
+				      reg, 0, 0);
+
+	sdei_cross_call_return(arg, err);
+}
+
+int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg)
+{
+	int err;
+	struct sdei_event *event;
+
+	WARN_ON(in_nmi());
+
+	mutex_lock(&sdei_events_lock);
+	if (sdei_event_find(event_num)) {
+		pr_warn("Event %u already registered\n", event_num);
+		err = -EBUSY;
+		goto unlock;
+	}
+
+	event = sdei_event_create(event_num, cb, arg);
+	if (IS_ERR(event)) {
+		err = PTR_ERR(event);
+		pr_warn("Failed to create event %u: %d\n", event_num, err);
+		goto unlock;
+	}
+
+	cpus_read_lock();
+	if (event->type == SDEI_EVENT_TYPE_SHARED) {
+		err = sdei_api_event_register(event->event_num,
+					      sdei_entry_point,
+					      event->registered,
+					      SDEI_EVENT_REGISTER_RM_ANY, 0);
+	} else {
+		err = sdei_do_cross_call(_local_event_register, event);
+		if (err)
+			sdei_do_cross_call(_local_event_unregister, event);
+	}
+
+	if (err) {
+		sdei_event_destroy(event);
+		pr_warn("Failed to register event %u: %d\n", event_num, err);
+		goto cpu_unlock;
+	}
+
+	spin_lock(&sdei_list_lock);
+	event->reregister = true;
+	spin_unlock(&sdei_list_lock);
+cpu_unlock:
+	cpus_read_unlock();
+unlock:
+	mutex_unlock(&sdei_events_lock);
+	return err;
+}
+
+static int sdei_reregister_shared(void)
+{
+	int err = 0;
+	struct sdei_event *event;
+
+	mutex_lock(&sdei_events_lock);
+	spin_lock(&sdei_list_lock);
+	list_for_each_entry(event, &sdei_list, list) {
+		if (event->type != SDEI_EVENT_TYPE_SHARED)
+			continue;
+
+		if (event->reregister) {
+			err = sdei_api_event_register(event->event_num,
+					sdei_entry_point, event->registered,
+					SDEI_EVENT_REGISTER_RM_ANY, 0);
+			if (err) {
+				pr_err("Failed to re-register event %u\n",
+				       event->event_num);
+				sdei_event_destroy_llocked(event);
+				break;
+			}
+		}
+
+		if (event->reenable) {
+			err = sdei_api_event_enable(event->event_num);
+			if (err) {
+				pr_err("Failed to re-enable event %u\n",
+				       event->event_num);
+				break;
+			}
+		}
+	}
+	spin_unlock(&sdei_list_lock);
+	mutex_unlock(&sdei_events_lock);
+
+	return err;
+}
+
+static int sdei_cpuhp_down(unsigned int cpu)
+{
+	struct sdei_event *event;
+	int err;
+
+	/* un-register private events */
+	spin_lock(&sdei_list_lock);
+	list_for_each_entry(event, &sdei_list, list) {
+		if (event->type == SDEI_EVENT_TYPE_SHARED)
+			continue;
+
+		err = sdei_do_local_call(_local_event_unregister, event);
+		if (err) {
+			pr_err("Failed to unregister event %u: %d\n",
+			       event->event_num, err);
+		}
+	}
+	spin_unlock(&sdei_list_lock);
+
+	return sdei_mask_local_cpu();
+}
+
+static int sdei_cpuhp_up(unsigned int cpu)
+{
+	struct sdei_event *event;
+	int err;
+
+	/* re-register/enable private events */
+	spin_lock(&sdei_list_lock);
+	list_for_each_entry(event, &sdei_list, list) {
+		if (event->type == SDEI_EVENT_TYPE_SHARED)
+			continue;
+
+		if (event->reregister) {
+			err = sdei_do_local_call(_local_event_register, event);
+			if (err) {
+				pr_err("Failed to re-register event %u: %d\n",
+				       event->event_num, err);
+			}
+		}
+
+		if (event->reenable) {
+			err = sdei_do_local_call(_local_event_enable, event);
+			if (err) {
+				pr_err("Failed to re-enable event %u: %d\n",
+				       event->event_num, err);
+			}
+		}
+	}
+	spin_unlock(&sdei_list_lock);
+
+	return sdei_unmask_local_cpu();
+}
+
+/* When entering idle, mask/unmask events for this cpu */
+static int sdei_pm_notifier(struct notifier_block *nb, unsigned long action,
+			    void *data)
+{
+	int rv;
+
+	WARN_ON_ONCE(preemptible());
+
+	switch (action) {
+	case CPU_PM_ENTER:
+		rv = sdei_mask_local_cpu();
+		break;
+	case CPU_PM_EXIT:
+	case CPU_PM_ENTER_FAILED:
+		rv = sdei_unmask_local_cpu();
+		break;
+	default:
+		return NOTIFY_DONE;
+	}
+
+	if (rv)
+		return notifier_from_errno(rv);
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block sdei_pm_nb = {
+	.notifier_call = sdei_pm_notifier,
+};
+
+static int sdei_device_suspend(struct device *dev)
+{
+	on_each_cpu(_ipi_mask_cpu, NULL, true);
+
+	return 0;
+}
+
+static int sdei_device_resume(struct device *dev)
+{
+	on_each_cpu(_ipi_unmask_cpu, NULL, true);
+
+	return 0;
+}
+
+/*
+ * We need all events to be reregistered when we resume from hibernate.
+ *
+ * The sequence is freeze->thaw. Reboot. freeze->restore. We unregister
+ * events during freeze, then re-register and re-enable them during thaw
+ * and restore.
+ */
+static int sdei_device_freeze(struct device *dev)
+{
+	int err;
+
+	/* unregister private events */
+	cpuhp_remove_state(sdei_hp_state);
+
+	err = sdei_unregister_shared();
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static int sdei_device_thaw(struct device *dev)
+{
+	int err;
+
+	/* re-register shared events */
+	err = sdei_reregister_shared();
+	if (err) {
+		pr_warn("Failed to re-register shared events...\n");
+		sdei_mark_interface_broken();
+		return err;
+	}
+
+	err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "SDEI",
+				&sdei_cpuhp_up, &sdei_cpuhp_down);
+	if (err < 0) {
+		pr_warn("Failed to re-register CPU hotplug notifier...\n");
+		return err;
+	}
+
+	sdei_hp_state = err;
+	return 0;
+}
+
+static int sdei_device_restore(struct device *dev)
+{
+	int err;
+
+	err = sdei_platform_reset();
+	if (err)
+		return err;
+
+	return sdei_device_thaw(dev);
+}
+
+static const struct dev_pm_ops sdei_pm_ops = {
+	.suspend = sdei_device_suspend,
+	.resume = sdei_device_resume,
+	.freeze = sdei_device_freeze,
+	.thaw = sdei_device_thaw,
+	.restore = sdei_device_restore,
+};
+
+/*
+ * Mask all CPUs and unregister all events on panic, reboot or kexec.
+ */
+static int sdei_reboot_notifier(struct notifier_block *nb, unsigned long action,
+				void *data)
+{
+	/*
+	 * We are going to reset the interface, after this there is no point
+	 * doing work when we take CPUs offline.
+	 */
+	cpuhp_remove_state(sdei_hp_state);
+
+	sdei_platform_reset();
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block sdei_reboot_nb = {
+	.notifier_call = sdei_reboot_notifier,
+};
+
+static void sdei_smccc_smc(unsigned long function_id,
+			   unsigned long arg0, unsigned long arg1,
+			   unsigned long arg2, unsigned long arg3,
+			   unsigned long arg4, struct arm_smccc_res *res)
+{
+	arm_smccc_smc(function_id, arg0, arg1, arg2, arg3, arg4, 0, 0, res);
+}
+NOKPROBE_SYMBOL(sdei_smccc_smc);
+
+static void sdei_smccc_hvc(unsigned long function_id,
+			   unsigned long arg0, unsigned long arg1,
+			   unsigned long arg2, unsigned long arg3,
+			   unsigned long arg4, struct arm_smccc_res *res)
+{
+	arm_smccc_hvc(function_id, arg0, arg1, arg2, arg3, arg4, 0, 0, res);
+}
+NOKPROBE_SYMBOL(sdei_smccc_hvc);
+
+int sdei_register_ghes(struct ghes *ghes, sdei_event_callback *normal_cb,
+		       sdei_event_callback *critical_cb)
+{
+	int err;
+	u64 result;
+	u32 event_num;
+	sdei_event_callback *cb;
+
+	if (!IS_ENABLED(CONFIG_ACPI_APEI_GHES))
+		return -EOPNOTSUPP;
+
+	event_num = ghes->generic->notify.vector;
+	if (event_num == 0) {
+		/*
+		 * Event 0 is reserved by the specification for
+		 * SDEI_EVENT_SIGNAL.
+		 */
+		return -EINVAL;
+	}
+
+	err = sdei_api_event_get_info(event_num, SDEI_EVENT_INFO_EV_PRIORITY,
+				      &result);
+	if (err)
+		return err;
+
+	if (result == SDEI_EVENT_PRIORITY_CRITICAL)
+		cb = critical_cb;
+	else
+		cb = normal_cb;
+
+	err = sdei_event_register(event_num, cb, ghes);
+	if (!err)
+		err = sdei_event_enable(event_num);
+
+	return err;
+}
+
+int sdei_unregister_ghes(struct ghes *ghes)
+{
+	int i;
+	int err;
+	u32 event_num = ghes->generic->notify.vector;
+
+	might_sleep();
+
+	if (!IS_ENABLED(CONFIG_ACPI_APEI_GHES))
+		return -EOPNOTSUPP;
+
+	/*
+	 * The event may be running on another CPU. Disable it
+	 * to stop new events, then try to unregister a few times.
+	 */
+	err = sdei_event_disable(event_num);
+	if (err)
+		return err;
+
+	for (i = 0; i < 3; i++) {
+		err = sdei_event_unregister(event_num);
+		if (err != -EINPROGRESS)
+			break;
+
+		schedule();
+	}
+
+	return err;
+}
+
+static int sdei_get_conduit(struct platform_device *pdev)
+{
+	const char *method;
+	struct device_node *np = pdev->dev.of_node;
+
+	sdei_firmware_call = NULL;
+	if (np) {
+		if (of_property_read_string(np, "method", &method)) {
+			pr_warn("missing \"method\" property\n");
+			return SMCCC_CONDUIT_NONE;
+		}
+
+		if (!strcmp("hvc", method)) {
+			sdei_firmware_call = &sdei_smccc_hvc;
+			return SMCCC_CONDUIT_HVC;
+		} else if (!strcmp("smc", method)) {
+			sdei_firmware_call = &sdei_smccc_smc;
+			return SMCCC_CONDUIT_SMC;
+		}
+
+		pr_warn("invalid \"method\" property: %s\n", method);
+	} else if (!acpi_disabled) {
+		if (acpi_psci_use_hvc()) {
+			sdei_firmware_call = &sdei_smccc_hvc;
+			return SMCCC_CONDUIT_HVC;
+		} else {
+			sdei_firmware_call = &sdei_smccc_smc;
+			return SMCCC_CONDUIT_SMC;
+		}
+	}
+
+	return SMCCC_CONDUIT_NONE;
+}
+
+static int sdei_probe(struct platform_device *pdev)
+{
+	int err;
+	u64 ver = 0;
+	int conduit;
+
+	conduit = sdei_get_conduit(pdev);
+	if (!sdei_firmware_call)
+		return 0;
+
+	err = sdei_api_get_version(&ver);
+	if (err) {
+		pr_err("Failed to get SDEI version: %d\n", err);
+		sdei_mark_interface_broken();
+		return err;
+	}
+
+	pr_info("SDEIv%d.%d (0x%x) detected in firmware.\n",
+		(int)SDEI_VERSION_MAJOR(ver), (int)SDEI_VERSION_MINOR(ver),
+		(int)SDEI_VERSION_VENDOR(ver));
+
+	if (SDEI_VERSION_MAJOR(ver) != 1) {
+		pr_warn("Conflicting SDEI version detected.\n");
+		sdei_mark_interface_broken();
+		return -EINVAL;
+	}
+
+	err = sdei_platform_reset();
+	if (err)
+		return err;
+
+	sdei_entry_point = sdei_arch_get_entry_point(conduit);
+	if (!sdei_entry_point) {
+		/* Not supported due to hardware or boot configuration */
+		sdei_mark_interface_broken();
+		return 0;
+	}
+
+	err = cpu_pm_register_notifier(&sdei_pm_nb);
+	if (err) {
+		pr_warn("Failed to register CPU PM notifier...\n");
+		goto error;
+	}
+
+	err = register_reboot_notifier(&sdei_reboot_nb);
+	if (err) {
+		pr_warn("Failed to register reboot notifier...\n");
+		goto remove_cpupm;
+	}
+
+	err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "SDEI",
+				&sdei_cpuhp_up, &sdei_cpuhp_down);
+	if (err < 0) {
+		pr_warn("Failed to register CPU hotplug notifier...\n");
+		goto remove_reboot;
+	}
+
+	sdei_hp_state = err;
+
+	return 0;
+
+remove_reboot:
+	unregister_reboot_notifier(&sdei_reboot_nb);
+
+remove_cpupm:
+	cpu_pm_unregister_notifier(&sdei_pm_nb);
+
+error:
+	sdei_mark_interface_broken();
+	return err;
+}
+
+static const struct of_device_id sdei_of_match[] = {
+	{ .compatible = "arm,sdei-1.0" },
+	{}
+};
+
+static struct platform_driver sdei_driver = {
+	.driver		= {
+		.name			= "sdei",
+		.pm			= &sdei_pm_ops,
+		.of_match_table		= sdei_of_match,
+	},
+	.probe		= sdei_probe,
+};
+
+static bool __init sdei_present_acpi(void)
+{
+	acpi_status status;
+	struct acpi_table_header *sdei_table_header;
+
+	if (acpi_disabled)
+		return false;
+
+	status = acpi_get_table(ACPI_SIG_SDEI, 0, &sdei_table_header);
+	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
+		const char *msg = acpi_format_exception(status);
+
+		pr_info("Failed to get ACPI:SDEI table, %s\n", msg);
+	}
+	if (ACPI_FAILURE(status))
+		return false;
+
+	acpi_put_table(sdei_table_header);
+
+	return true;
+}
+
+void __init acpi_sdei_init(void)
+{
+	struct platform_device *pdev;
+	int ret;
+
+	if (!sdei_present_acpi())
+		return;
+
+	pdev = platform_device_register_simple(sdei_driver.driver.name,
+					       0, NULL, 0);
+	if (IS_ERR(pdev)) {
+		ret = PTR_ERR(pdev);
+		platform_driver_unregister(&sdei_driver);
+		pr_info("Failed to register ACPI:SDEI platform device %d\n",
+			ret);
+	}
+}
+
+static int __init sdei_init(void)
+{
+	return platform_driver_register(&sdei_driver);
+}
+arch_initcall(sdei_init);
+
+int sdei_event_handler(struct pt_regs *regs,
+		       struct sdei_registered_event *arg)
+{
+	int err;
+	u32 event_num = arg->event_num;
+
+	err = arg->callback(event_num, regs, arg->callback_arg);
+	if (err)
+		pr_err_ratelimited("event %u on CPU %u failed with error: %d\n",
+				   event_num, smp_processor_id(), err);
+
+	return err;
+}
+NOKPROBE_SYMBOL(sdei_event_handler);
+
+void sdei_handler_abort(void)
+{
+	/*
+	 * If the crash happened in an SDEI event handler then we need to
+	 * finish the handler with the firmware so that we can have working
+	 * interrupts in the crash kernel.
+	 */
+	if (__this_cpu_read(sdei_active_critical_event)) {
+	        pr_warn("still in SDEI critical event context, attempting to finish handler.\n");
+	        __sdei_handler_abort();
+	        __this_cpu_write(sdei_active_critical_event, NULL);
+	}
+	if (__this_cpu_read(sdei_active_normal_event)) {
+	        pr_warn("still in SDEI normal event context, attempting to finish handler.\n");
+	        __sdei_handler_abort();
+	        __this_cpu_write(sdei_active_normal_event, NULL);
+	}
+}