diff options
Diffstat (limited to 'drivers/firmware/arm_sdei.c')
| -rw-r--r-- | drivers/firmware/arm_sdei.c | 1086 |
1 files changed, 1086 insertions, 0 deletions
diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c new file mode 100644 index 000000000..e809f4d9a --- /dev/null +++ b/drivers/firmware/arm_sdei.c @@ -0,0 +1,1086 @@ +// 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/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> +#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 { + /* 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) (arg.event = event, \ + arg.first_error = 0, \ + atomic_set(&arg.errors, 0)) + +static inline int sdei_do_cross_call(void *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; + } + + /* 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; + } else { + int cpu; + struct sdei_registered_event __percpu *regs; + + regs = alloc_percpu(struct sdei_registered_event); + if (!regs) { + kfree(event); + return ERR_PTR(-ENOMEM); + } + + 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; + } + + 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); + else + free_percpu(event->private_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); +} + +/* Called directly by the hotplug callbacks */ +static void _local_event_enable(void *data) +{ + int err; + struct sdei_crosscall_args *arg = data; + + WARN_ON_ONCE(preemptible()); + + 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; +} +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); +} + +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; +} +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); +} + +/* Called directly by the hotplug callbacks */ +static void _local_event_unregister(void *data) +{ + int err; + struct sdei_crosscall_args *arg = data; + + WARN_ON_ONCE(preemptible()); + + err = sdei_api_event_unregister(arg->event->event_num); + + sdei_cross_call_return(arg, err); +} + +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 sdei_do_cross_call(_local_event_unregister, event); +} + +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; + } + + spin_lock(&sdei_list_lock); + event->reregister = false; + event->reenable = false; + spin_unlock(&sdei_list_lock); + + 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); + +/* + * 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_event_unregister(event); + 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; + + WARN_ON(preemptible()); + + 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); +} + +static int _sdei_event_register(struct sdei_event *event) +{ + int err; + + 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); + + err = sdei_do_cross_call(_local_event_register, event); + if (err) + sdei_do_cross_call(_local_event_unregister, event); + + return 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); + 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; + } + + cpus_read_lock(); + err = _sdei_event_register(event); + if (err) { + sdei_event_destroy(event); + pr_warn("Failed to register event %u: %d\n", event_num, + err); + } else { + spin_lock(&sdei_list_lock); + event->reregister = true; + spin_unlock(&sdei_list_lock); + } + cpus_read_unlock(); + } while (0); + mutex_unlock(&sdei_events_lock); + + return err; +} +EXPORT_SYMBOL(sdei_event_register); + +static int sdei_reregister_event(struct sdei_event *event) +{ + int err; + + lockdep_assert_held(&sdei_events_lock); + + err = _sdei_event_register(event); + if (err) { + pr_err("Failed to re-register event %u\n", event->event_num); + sdei_event_destroy(event); + return err; + } + + if (event->reenable) { + 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) + pr_err("Failed to re-enable event %u\n", event->event_num); + + 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_reregister_event(event); + if (err) + 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; + struct sdei_crosscall_args arg; + + /* 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; + + CROSSCALL_INIT(arg, event); + /* call the cross-call function locally... */ + _local_event_unregister(&arg); + if (arg.first_error) + pr_err("Failed to unregister event %u: %d\n", + event->event_num, arg.first_error); + } + spin_unlock(&sdei_list_lock); + + return sdei_mask_local_cpu(); +} + +static int sdei_cpuhp_up(unsigned int cpu) +{ + struct sdei_event *event; + struct sdei_crosscall_args arg; + + /* 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) { + CROSSCALL_INIT(arg, event); + /* call the cross-call function locally... */ + _local_event_register(&arg); + if (arg.first_error) + pr_err("Failed to re-register event %u: %d\n", + event->event_num, arg.first_error); + } + + if (event->reenable) { + CROSSCALL_INIT(arg, event); + _local_event_enable(&arg); + if (arg.first_error) + pr_err("Failed to re-enable event %u: %d\n", + event->event_num, arg.first_error); + } + } + 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; + + 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(CPUHP_AP_ARM_SDEI_STARTING); + + 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_ARM_SDEI_STARTING, "SDEI", + &sdei_cpuhp_up, &sdei_cpuhp_down); + if (err) + pr_warn("Failed to re-register CPU hotplug notifier...\n"); + + return err; +} + +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(CPUHP_AP_ARM_SDEI_STARTING); + + 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); +} + +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); + } else if (IS_ENABLED(CONFIG_ACPI) && !acpi_disabled) { + if (acpi_psci_use_hvc()) { + sdei_firmware_call = &sdei_smccc_hvc; + return CONDUIT_HVC; + } else { + sdei_firmware_call = &sdei_smccc_smc; + return CONDUIT_SMC; + } + } + + 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; + } + + 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_ARM_SDEI_STARTING, "SDEI", + &sdei_cpuhp_up, &sdei_cpuhp_down); + if (err) { + pr_warn("Failed to register CPU hotplug notifier...\n"); + goto remove_reboot; + } + + 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_dt(void) +{ + 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); + if (!np) + return false; + of_node_put(np); + + return true; +} + +static bool __init sdei_present_acpi(void) +{ + acpi_status status; + struct platform_device *pdev; + 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; + + pdev = platform_device_register_simple(sdei_driver.driver.name, 0, NULL, + 0); + if (IS_ERR(pdev)) + return false; + + return true; +} + +static int __init sdei_init(void) +{ + if (sdei_present_dt() || sdei_present_acpi()) + platform_driver_register(&sdei_driver); + + return 0; +} + +/* + * On an ACPI system SDEI needs to be ready before HEST:GHES tries to register + * its events. ACPI is initialised from a subsys_initcall(), GHES is initialised + * by device_initcall(). We want to be called in the middle. + */ +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); |