[PATCH v6 07/16] firmware: arm_sdei: Add driver for Software Delegated Exceptions
James Morse
james.morse at arm.com
Mon Jan 8 07:38:09 PST 2018
The Software Delegated Exception Interface (SDEI) is an ARM standard
for registering callbacks from the platform firmware into the OS.
This is typically used to implement firmware notifications (such as
firmware-first RAS) or promote an IRQ that has been promoted to a
firmware-assisted NMI.
Add the code for detecting the SDEI version and the framework for
registering and unregistering events. Subsequent patches will add the
arch-specific backend code and the necessary power management hooks.
Only shared events are supported, power management, private events and
discovery for ACPI systems will be added by later patches.
Signed-off-by: James Morse <james.morse at arm.com>
---
Changes since v4:
* Ripped out passed in gfp_t, it was masking a bug, all allocations are now
GFP_KERNEL.
* Switched spin_lock for a mutex and added a spin_lock around the list, this
fixes the bug and makes a later cpu-hotplug interaction easier.
* Dropped Catalin's ack
Changes since v3:
* Depend on arm64 from the beginning, add a placeholder arch asm file.
* Added MAINTAINER record
* Renamed sdei.h files to arm_sdei.h
* Removed IS_SDEI_CALL(), KVM won't need this...
MAINTAINERS | 9 +
arch/arm64/include/asm/sdei.h | 8 +
drivers/firmware/Kconfig | 8 +
drivers/firmware/Makefile | 1 +
drivers/firmware/arm_sdei.c | 619 ++++++++++++++++++++++++++++++++++++++++++
include/linux/arm_sdei.h | 79 ++++++
include/uapi/linux/arm_sdei.h | 73 +++++
7 files changed, 797 insertions(+)
create mode 100644 arch/arm64/include/asm/sdei.h
create mode 100644 drivers/firmware/arm_sdei.c
create mode 100644 include/linux/arm_sdei.h
create mode 100644 include/uapi/linux/arm_sdei.h
diff --git a/MAINTAINERS b/MAINTAINERS
index 82ad0eabce4f..c06885c4c0f1 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12618,6 +12618,15 @@ L: linux-media at vger.kernel.org
S: Supported
F: drivers/media/pci/solo6x10/
+SOFTWARE DELEGATED EXCEPTION INTERFACE (SDEI)
+M: James Morse <james.morse at arm.com>
+L: linux-arm-kernel at lists.infradead.org
+S: Maintained
+F: Documentation/devicetree/bindings/arm/firmware/sdei.txt
+F: drivers/firmware/arm_sdei.c
+F: include/linux/sdei.h
+F: include/uapi/linux/sdei.h
+
SOFTWARE RAID (Multiple Disks) SUPPORT
M: Shaohua Li <shli at kernel.org>
L: linux-raid at vger.kernel.org
diff --git a/arch/arm64/include/asm/sdei.h b/arch/arm64/include/asm/sdei.h
new file mode 100644
index 000000000000..59f26b6e673d
--- /dev/null
+++ b/arch/arm64/include/asm/sdei.h
@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2017 Arm Ltd.
+#ifndef __ASM_SDEI_H
+#define __ASM_SDEI_H
+
+/* Later patches add the arch specific bits */
+
+#endif /* __ASM_SDEI_H */
diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index fa87a055905e..e77f77caa0f3 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -48,6 +48,14 @@ config ARM_SCPI_POWER_DOMAIN
This enables support for the SCPI power domains which can be
enabled or disabled via the SCP firmware
+config ARM_SDE_INTERFACE
+ bool "ARM Software Delegated Exception Interface (SDEI)"
+ depends on ARM64
+ help
+ The Software Delegated Exception Interface (SDEI) is an ARM
+ standard for registering callbacks from the platform firmware
+ into the OS. This is typically used to implement RAS notifications.
+
config EDD
tristate "BIOS Enhanced Disk Drive calls determine boot disk"
depends on X86
diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile
index feaa890197f3..b248238ddc6a 100644
--- a/drivers/firmware/Makefile
+++ b/drivers/firmware/Makefile
@@ -6,6 +6,7 @@ obj-$(CONFIG_ARM_PSCI_FW) += psci.o
obj-$(CONFIG_ARM_PSCI_CHECKER) += psci_checker.o
obj-$(CONFIG_ARM_SCPI_PROTOCOL) += arm_scpi.o
obj-$(CONFIG_ARM_SCPI_POWER_DOMAIN) += scpi_pm_domain.o
+obj-$(CONFIG_ARM_SDE_INTERFACE) += arm_sdei.o
obj-$(CONFIG_DMI) += dmi_scan.o
obj-$(CONFIG_DMI_SYSFS) += dmi-sysfs.o
obj-$(CONFIG_EDD) += edd.o
diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c
new file mode 100644
index 000000000000..8da173cc7e43
--- /dev/null
+++ b/drivers/firmware/arm_sdei.c
@@ -0,0 +1,619 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2017 Arm Ltd.
+#define pr_fmt(fmt) "sdei: " fmt
+
+#include <linux/acpi.h>
+#include <linux/arm_sdei.h>
+#include <linux/arm-smccc.h>
+#include <linux/bitops.h>
+#include <linux/compiler.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/of.h>
+#include <linux/of_platform.h>
+#include <linux/percpu.h>
+#include <linux/platform_device.h>
+#include <linux/ptrace.h>
+#include <linux/preempt.h>
+#include <linux/slab.h>
+#include <linux/smp.h>
+#include <linux/spinlock.h>
+#include <linux/uaccess.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;
+
+struct sdei_event {
+ struct list_head list;
+ u32 event_num;
+ u8 type;
+ u8 priority;
+
+ /* This pointer is handed to firmware as the event argument. */
+ struct sdei_registered_event *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);
+
+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;
+ }
+
+ /* Not an error value ... */
+ return sdei_err;
+}
+
+/*
+ * If x0 is any of these values, then the call failed, use sdei_to_linux_errno()
+ * to translate.
+ */
+static int sdei_is_err(struct arm_smccc_res *res)
+{
+ switch (res->a0) {
+ case SDEI_NOT_SUPPORTED:
+ case SDEI_INVALID_PARAMETERS:
+ case SDEI_DENIED:
+ case SDEI_PENDING:
+ case SDEI_OUT_OF_RESOURCE:
+ return true;
+ }
+
+ return false;
+}
+
+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 = 0;
+ struct arm_smccc_res res;
+
+ if (sdei_firmware_call) {
+ sdei_firmware_call(function_id, arg0, arg1, arg2, arg3, arg4,
+ &res);
+ if (sdei_is_err(&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;
+}
+
+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(sizeof(*event), GFP_KERNEL);
+ if (!event)
+ return ERR_PTR(-ENOMEM);
+
+ 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) {
+ kfree(event);
+ return ERR_PTR(err);
+ }
+ event->priority = result;
+
+ err = sdei_api_event_get_info(event_num, SDEI_EVENT_INFO_EV_TYPE,
+ &result);
+ if (err) {
+ kfree(event);
+ return ERR_PTR(err);
+ }
+ event->type = result;
+
+ if (event->type == SDEI_EVENT_TYPE_SHARED) {
+ reg = kzalloc(sizeof(*reg), GFP_KERNEL);
+ if (!reg) {
+ kfree(event);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ reg->event_num = event_num;
+ reg->priority = event->priority;
+
+ reg->callback = cb;
+ reg->callback_arg = cb_arg;
+ event->registered = reg;
+ }
+
+ if (sdei_event_find(event_num)) {
+ kfree(event->registered);
+ kfree(event);
+ event = ERR_PTR(-EBUSY);
+ } else {
+ spin_lock(&sdei_list_lock);
+ list_add(&event->list, &sdei_list);
+ spin_unlock(&sdei_list_lock);
+ }
+
+ return event;
+}
+
+static void sdei_event_destroy(struct sdei_event *event)
+{
+ lockdep_assert_held(&sdei_events_lock);
+
+ spin_lock(&sdei_list_lock);
+ list_del(&event->list);
+ spin_unlock(&sdei_list_lock);
+
+ if (event->type == SDEI_EVENT_TYPE_SHARED)
+ kfree(event->registered);
+
+ kfree(event);
+}
+
+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;
+
+ WARN_ON_ONCE(preemptible());
+
+ 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)
+{
+ sdei_mask_local_cpu();
+}
+
+int sdei_unmask_local_cpu(void)
+{
+ int err;
+
+ WARN_ON_ONCE(preemptible());
+
+ 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)
+{
+ sdei_unmask_local_cpu();
+}
+
+static void _ipi_private_reset(void *ignored)
+{
+ int err;
+
+ 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);
+}
+
+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;
+ }
+
+ if (event->type == SDEI_EVENT_TYPE_SHARED)
+ err = sdei_api_event_enable(event->event_num);
+ mutex_unlock(&sdei_events_lock);
+
+ return err;
+}
+EXPORT_SYMBOL(sdei_event_enable);
+
+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);
+}
+
+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;
+ }
+
+ if (event->type == SDEI_EVENT_TYPE_SHARED)
+ err = sdei_api_event_disable(event->event_num);
+ mutex_unlock(&sdei_events_lock);
+
+ return err;
+}
+EXPORT_SYMBOL(sdei_event_disable);
+
+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);
+}
+
+static int _sdei_event_unregister(struct sdei_event *event)
+{
+ lockdep_assert_held(&sdei_events_lock);
+
+ if (event->type == SDEI_EVENT_TYPE_SHARED)
+ return sdei_api_event_unregister(event->event_num);
+
+ return -EINVAL;
+}
+
+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);
+ do {
+ if (!event) {
+ pr_warn("Event %u not registered\n", event_num);
+ err = -ENOENT;
+ break;
+ }
+
+ err = _sdei_event_unregister(event);
+ if (err)
+ break;
+
+ sdei_event_destroy(event);
+ } while (0);
+ mutex_unlock(&sdei_events_lock);
+
+ return err;
+}
+EXPORT_SYMBOL(sdei_event_unregister);
+
+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);
+}
+
+static int _sdei_event_register(struct sdei_event *event)
+{
+ lockdep_assert_held(&sdei_events_lock);
+
+ if (event->type == SDEI_EVENT_TYPE_SHARED)
+ return sdei_api_event_register(event->event_num,
+ sdei_entry_point,
+ event->registered,
+ SDEI_EVENT_REGISTER_RM_ANY, 0);
+
+ return -EINVAL;
+}
+
+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);
+ do {
+ if (sdei_event_find(event_num)) {
+ pr_warn("Event %u already registered\n", event_num);
+ err = -EBUSY;
+ break;
+ }
+
+ 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);
+ break;
+ }
+
+ err = _sdei_event_register(event);
+ if (err) {
+ sdei_event_destroy(event);
+ pr_warn("Failed to register event %u: %d\n", event_num,
+ err);
+ }
+ } while (0);
+ mutex_unlock(&sdei_events_lock);
+
+ return err;
+}
+EXPORT_SYMBOL(sdei_event_register);
+
+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);
+}
+
+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);
+}
+
+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 CONDUIT_INVALID;
+ }
+
+ if (!strcmp("hvc", method)) {
+ sdei_firmware_call = &sdei_smccc_hvc;
+ return CONDUIT_HVC;
+ } else if (!strcmp("smc", method)) {
+ sdei_firmware_call = &sdei_smccc_smc;
+ return CONDUIT_SMC;
+ }
+
+ pr_warn("invalid \"method\" property: %s\n", method);
+ }
+
+ return CONDUIT_INVALID;
+}
+
+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 == -EOPNOTSUPP)
+ pr_err("advertised but not implemented in platform firmware\n");
+ 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;
+ }
+
+ on_each_cpu(&_ipi_unmask_cpu, NULL, false);
+
+ return 0;
+}
+
+static const struct of_device_id sdei_of_match[] = {
+ { .compatible = "arm,sdei-1.0" },
+ {}
+};
+
+static struct platform_driver sdei_driver = {
+ .driver = {
+ .name = "sdei",
+ .of_match_table = sdei_of_match,
+ },
+ .probe = sdei_probe,
+};
+
+static bool __init sdei_present_dt(void)
+{
+ struct platform_device *pdev;
+ struct device_node *np, *fw_np;
+
+ fw_np = of_find_node_by_name(NULL, "firmware");
+ if (!fw_np)
+ return false;
+
+ np = of_find_matching_node(fw_np, sdei_of_match);
+ of_node_put(fw_np);
+ if (!np)
+ return false;
+
+ pdev = of_platform_device_create(np, sdei_driver.driver.name, NULL);
+ of_node_put(np);
+ if (IS_ERR(pdev))
+ return false;
+
+ return true;
+}
+
+static int __init sdei_init(void)
+{
+ if (sdei_present_dt())
+ platform_driver_register(&sdei_driver);
+
+ return 0;
+}
+
+subsys_initcall_sync(sdei_init);
+
+int sdei_event_handler(struct pt_regs *regs,
+ struct sdei_registered_event *arg)
+{
+ int err;
+ mm_segment_t orig_addr_limit;
+ u32 event_num = arg->event_num;
+
+ orig_addr_limit = get_fs();
+ set_fs(USER_DS);
+
+ 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);
+
+ set_fs(orig_addr_limit);
+
+ return err;
+}
+NOKPROBE_SYMBOL(sdei_event_handler);
diff --git a/include/linux/arm_sdei.h b/include/linux/arm_sdei.h
new file mode 100644
index 000000000000..942afbd544b7
--- /dev/null
+++ b/include/linux/arm_sdei.h
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2017 Arm Ltd.
+#ifndef __LINUX_ARM_SDEI_H
+#define __LINUX_ARM_SDEI_H
+
+#include <uapi/linux/arm_sdei.h>
+
+enum sdei_conduit_types {
+ CONDUIT_INVALID = 0,
+ CONDUIT_SMC,
+ CONDUIT_HVC,
+};
+
+#include <asm/sdei.h>
+
+/* Arch code should override this to set the entry point from firmware... */
+#ifndef sdei_arch_get_entry_point
+#define sdei_arch_get_entry_point(conduit) (0)
+#endif
+
+/*
+ * When an event occurs sdei_event_handler() will call a user-provided callback
+ * like this in NMI context on the CPU that received the event.
+ */
+typedef int (sdei_event_callback)(u32 event, struct pt_regs *regs, void *arg);
+
+/*
+ * Register your callback to claim an event. The event must be described
+ * by firmware.
+ */
+int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg);
+
+/*
+ * Calls to sdei_event_unregister() may return EINPROGRESS. Keep calling
+ * it until it succeeds.
+ */
+int sdei_event_unregister(u32 event_num);
+
+int sdei_event_enable(u32 event_num);
+int sdei_event_disable(u32 event_num);
+
+#ifdef CONFIG_ARM_SDE_INTERFACE
+/* For use by arch code when CPU hotplug notifiers are not appropriate. */
+int sdei_mask_local_cpu(void);
+int sdei_unmask_local_cpu(void);
+#else
+static inline int sdei_mask_local_cpu(void) { return 0; }
+static inline int sdei_unmask_local_cpu(void) { return 0; }
+#endif /* CONFIG_ARM_SDE_INTERFACE */
+
+
+/*
+ * This struct represents an event that has been registered. The driver
+ * maintains a list of all events, and which ones are registered. (Private
+ * events have one entry in the list, but are registered on each CPU).
+ * A pointer to this struct is passed to firmware, and back to the event
+ * handler. The event handler can then use this to invoke the registered
+ * callback, without having to walk the list.
+ *
+ * For CPU private events, this structure is per-cpu.
+ */
+struct sdei_registered_event {
+ /* For use by arch code: */
+ struct pt_regs interrupted_regs;
+
+ sdei_event_callback *callback;
+ void *callback_arg;
+ u32 event_num;
+ u8 priority;
+};
+
+/* The arch code entry point should then call this when an event arrives. */
+int notrace sdei_event_handler(struct pt_regs *regs,
+ struct sdei_registered_event *arg);
+
+/* arch code may use this to retrieve the extra registers. */
+int sdei_api_event_context(u32 query, u64 *result);
+
+#endif /* __LINUX_ARM_SDEI_H */
diff --git a/include/uapi/linux/arm_sdei.h b/include/uapi/linux/arm_sdei.h
new file mode 100644
index 000000000000..af0630ba5437
--- /dev/null
+++ b/include/uapi/linux/arm_sdei.h
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/* Copyright (C) 2017 Arm Ltd. */
+#ifndef _UAPI_LINUX_ARM_SDEI_H
+#define _UAPI_LINUX_ARM_SDEI_H
+
+#define SDEI_1_0_FN_BASE 0xC4000020
+#define SDEI_1_0_MASK 0xFFFFFFE0
+#define SDEI_1_0_FN(n) (SDEI_1_0_FN_BASE + (n))
+
+#define SDEI_1_0_FN_SDEI_VERSION SDEI_1_0_FN(0x00)
+#define SDEI_1_0_FN_SDEI_EVENT_REGISTER SDEI_1_0_FN(0x01)
+#define SDEI_1_0_FN_SDEI_EVENT_ENABLE SDEI_1_0_FN(0x02)
+#define SDEI_1_0_FN_SDEI_EVENT_DISABLE SDEI_1_0_FN(0x03)
+#define SDEI_1_0_FN_SDEI_EVENT_CONTEXT SDEI_1_0_FN(0x04)
+#define SDEI_1_0_FN_SDEI_EVENT_COMPLETE SDEI_1_0_FN(0x05)
+#define SDEI_1_0_FN_SDEI_EVENT_COMPLETE_AND_RESUME SDEI_1_0_FN(0x06)
+#define SDEI_1_0_FN_SDEI_EVENT_UNREGISTER SDEI_1_0_FN(0x07)
+#define SDEI_1_0_FN_SDEI_EVENT_STATUS SDEI_1_0_FN(0x08)
+#define SDEI_1_0_FN_SDEI_EVENT_GET_INFO SDEI_1_0_FN(0x09)
+#define SDEI_1_0_FN_SDEI_EVENT_ROUTING_SET SDEI_1_0_FN(0x0A)
+#define SDEI_1_0_FN_SDEI_PE_MASK SDEI_1_0_FN(0x0B)
+#define SDEI_1_0_FN_SDEI_PE_UNMASK SDEI_1_0_FN(0x0C)
+#define SDEI_1_0_FN_SDEI_INTERRUPT_BIND SDEI_1_0_FN(0x0D)
+#define SDEI_1_0_FN_SDEI_INTERRUPT_RELEASE SDEI_1_0_FN(0x0E)
+#define SDEI_1_0_FN_SDEI_PRIVATE_RESET SDEI_1_0_FN(0x11)
+#define SDEI_1_0_FN_SDEI_SHARED_RESET SDEI_1_0_FN(0x12)
+
+#define SDEI_VERSION_MAJOR_SHIFT 48
+#define SDEI_VERSION_MAJOR_MASK 0x7fff
+#define SDEI_VERSION_MINOR_SHIFT 32
+#define SDEI_VERSION_MINOR_MASK 0xffff
+#define SDEI_VERSION_VENDOR_SHIFT 0
+#define SDEI_VERSION_VENDOR_MASK 0xffffffff
+
+#define SDEI_VERSION_MAJOR(x) (x>>SDEI_VERSION_MAJOR_SHIFT & SDEI_VERSION_MAJOR_MASK)
+#define SDEI_VERSION_MINOR(x) (x>>SDEI_VERSION_MINOR_SHIFT & SDEI_VERSION_MINOR_MASK)
+#define SDEI_VERSION_VENDOR(x) (x>>SDEI_VERSION_VENDOR_SHIFT & SDEI_VERSION_VENDOR_MASK)
+
+/* SDEI return values */
+#define SDEI_SUCCESS 0
+#define SDEI_NOT_SUPPORTED -1
+#define SDEI_INVALID_PARAMETERS -2
+#define SDEI_DENIED -3
+#define SDEI_PENDING -5
+#define SDEI_OUT_OF_RESOURCE -10
+
+/* EVENT_REGISTER flags */
+#define SDEI_EVENT_REGISTER_RM_ANY 0
+#define SDEI_EVENT_REGISTER_RM_PE 1
+
+/* EVENT_STATUS return value bits */
+#define SDEI_EVENT_STATUS_RUNNING 2
+#define SDEI_EVENT_STATUS_ENABLED 1
+#define SDEI_EVENT_STATUS_REGISTERED 0
+
+/* EVENT_COMPLETE status values */
+#define SDEI_EV_HANDLED 0
+#define SDEI_EV_FAILED 1
+
+/* GET_INFO values */
+#define SDEI_EVENT_INFO_EV_TYPE 0
+#define SDEI_EVENT_INFO_EV_SIGNALED 1
+#define SDEI_EVENT_INFO_EV_PRIORITY 2
+#define SDEI_EVENT_INFO_EV_ROUTING_MODE 3
+#define SDEI_EVENT_INFO_EV_ROUTING_AFF 4
+
+/* and their results */
+#define SDEI_EVENT_TYPE_PRIVATE 0
+#define SDEI_EVENT_TYPE_SHARED 1
+#define SDEI_EVENT_PRIORITY_NORMAL 0
+#define SDEI_EVENT_PRIORITY_CRITICAL 1
+
+#endif /* _UAPI_LINUX_ARM_SDEI_H */
--
2.15.0
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