efi_loader: implement ReinstallProtocolInterface

[u-boot] / lib / efi_loader / efi_boottime.c

// SPDX-License-Identifier: GPL-2.0+
/*
 *  EFI application boot time services
 *
 *  Copyright (c) 2016 Alexander Graf
 */

#include <common.h>
#include <div64.h>
#include <efi_loader.h>
#include <environment.h>
#include <malloc.h>
#include <linux/libfdt_env.h>
#include <u-boot/crc.h>
#include <bootm.h>
#include <inttypes.h>
#include <watchdog.h>

DECLARE_GLOBAL_DATA_PTR;

/* Task priority level */
static efi_uintn_t efi_tpl = TPL_APPLICATION;

/* This list contains all the EFI objects our payload has access to */
LIST_HEAD(efi_obj_list);

/* List of all events */
LIST_HEAD(efi_events);

/*
 * If we're running on nasty systems (32bit ARM booting into non-EFI Linux)
 * we need to do trickery with caches. Since we don't want to break the EFI
 * aware boot path, only apply hacks when loading exiting directly (breaking
 * direct Linux EFI booting along the way - oh well).
 */
static bool efi_is_direct_boot = true;

/*
 * EFI can pass arbitrary additional "tables" containing vendor specific
 * information to the payload. One such table is the FDT table which contains
 * a pointer to a flattened device tree blob.
 *
 * In most cases we want to pass an FDT to the payload, so reserve one slot of
 * config table space for it. The pointer gets populated by do_bootefi_exec().
 */
static struct efi_configuration_table __efi_runtime_data efi_conf_table[2];

#ifdef CONFIG_ARM
/*
 * The "gd" pointer lives in a register on ARM and AArch64 that we declare
 * fixed when compiling U-Boot. However, the payload does not know about that
 * restriction so we need to manually swap its and our view of that register on
 * EFI callback entry/exit.
 */
static volatile void *efi_gd, *app_gd;
#endif

static int entry_count;
static int nesting_level;
/* GUID of the device tree table */
const efi_guid_t efi_guid_fdt = EFI_FDT_GUID;
/* GUID of the EFI_DRIVER_BINDING_PROTOCOL */
const efi_guid_t efi_guid_driver_binding_protocol =
                        EFI_DRIVER_BINDING_PROTOCOL_GUID;

/* event group ExitBootServices() invoked */
const efi_guid_t efi_guid_event_group_exit_boot_services =
                        EFI_EVENT_GROUP_EXIT_BOOT_SERVICES;
/* event group SetVirtualAddressMap() invoked */
const efi_guid_t efi_guid_event_group_virtual_address_change =
                        EFI_EVENT_GROUP_VIRTUAL_ADDRESS_CHANGE;
/* event group memory map changed */
const efi_guid_t efi_guid_event_group_memory_map_change =
                        EFI_EVENT_GROUP_MEMORY_MAP_CHANGE;
/* event group boot manager about to boot */
const efi_guid_t efi_guid_event_group_ready_to_boot =
                        EFI_EVENT_GROUP_READY_TO_BOOT;
/* event group ResetSystem() invoked (before ExitBootServices) */
const efi_guid_t efi_guid_event_group_reset_system =
                        EFI_EVENT_GROUP_RESET_SYSTEM;

static efi_status_t EFIAPI efi_disconnect_controller(
                                        efi_handle_t controller_handle,
                                        efi_handle_t driver_image_handle,
                                        efi_handle_t child_handle);

/* Called on every callback entry */
int __efi_entry_check(void)
{
        int ret = entry_count++ == 0;
#ifdef CONFIG_ARM
        assert(efi_gd);
        app_gd = gd;
        gd = efi_gd;
#endif
        return ret;
}

/* Called on every callback exit */
int __efi_exit_check(void)
{
        int ret = --entry_count == 0;
#ifdef CONFIG_ARM
        gd = app_gd;
#endif
        return ret;
}

/* Called from do_bootefi_exec() */
void efi_save_gd(void)
{
#ifdef CONFIG_ARM
        efi_gd = gd;
#endif
}

/*
 * Special case handler for error/abort that just forces things back
 * to u-boot world so we can dump out an abort msg, without any care
 * about returning back to UEFI world.
 */
void efi_restore_gd(void)
{
#ifdef CONFIG_ARM
        /* Only restore if we're already in EFI context */
        if (!efi_gd)
                return;
        gd = efi_gd;
#endif
}

/*
 * Return a string for indenting with two spaces per level. A maximum of ten
 * indent levels is supported. Higher indent levels will be truncated.
 *
 * @level       indent level
 * @return      indent string
 */
static const char *indent_string(int level)
{
        const char *indent = "                    ";
        const int max = strlen(indent);

        level = min(max, level * 2);
        return &indent[max - level];
}

const char *__efi_nesting(void)
{
        return indent_string(nesting_level);
}

const char *__efi_nesting_inc(void)
{
        return indent_string(nesting_level++);
}

const char *__efi_nesting_dec(void)
{
        return indent_string(--nesting_level);
}

/*
 * Queue an EFI event.
 *
 * This function queues the notification function of the event for future
 * execution.
 *
 * The notification function is called if the task priority level of the
 * event is higher than the current task priority level.
 *
 * For the SignalEvent service see efi_signal_event_ext.
 *
 * @event       event to signal
 * @check_tpl   check the TPL level
 */
static void efi_queue_event(struct efi_event *event, bool check_tpl)
{
        if (event->notify_function) {
                event->is_queued = true;
                /* Check TPL */
                if (check_tpl && efi_tpl >= event->notify_tpl)
                        return;
                EFI_CALL_VOID(event->notify_function(event,
                                                     event->notify_context));
        }
        event->is_queued = false;
}

/*
 * Signal an EFI event.
 *
 * This function signals an event. If the event belongs to an event group
 * all events of the group are signaled. If they are of type EVT_NOTIFY_SIGNAL
 * their notification function is queued.
 *
 * For the SignalEvent service see efi_signal_event_ext.
 *
 * @event       event to signal
 * @check_tpl   check the TPL level
 */
void efi_signal_event(struct efi_event *event, bool check_tpl)
{
        if (event->group) {
                struct efi_event *evt;

                /*
                 * The signaled state has to set before executing any
                 * notification function
                 */
                list_for_each_entry(evt, &efi_events, link) {
                        if (!evt->group || guidcmp(evt->group, event->group))
                                continue;
                        if (evt->is_signaled)
                                continue;
                        evt->is_signaled = true;
                        if (evt->type & EVT_NOTIFY_SIGNAL &&
                            evt->notify_function)
                                evt->is_queued = true;
                }
                list_for_each_entry(evt, &efi_events, link) {
                        if (!evt->group || guidcmp(evt->group, event->group))
                                continue;
                        if (evt->is_queued)
                                efi_queue_event(evt, check_tpl);
                }
        } else if (!event->is_signaled) {
                event->is_signaled = true;
                if (event->type & EVT_NOTIFY_SIGNAL)
                        efi_queue_event(event, check_tpl);
        }
}

/*
 * Raise the task priority level.
 *
 * This function implements the RaiseTpl service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @new_tpl     new value of the task priority level
 * @return      old value of the task priority level
 */
static unsigned long EFIAPI efi_raise_tpl(efi_uintn_t new_tpl)
{
        efi_uintn_t old_tpl = efi_tpl;

        EFI_ENTRY("0x%zx", new_tpl);

        if (new_tpl < efi_tpl)
                debug("WARNING: new_tpl < current_tpl in %s\n", __func__);
        efi_tpl = new_tpl;
        if (efi_tpl > TPL_HIGH_LEVEL)
                efi_tpl = TPL_HIGH_LEVEL;

        EFI_EXIT(EFI_SUCCESS);
        return old_tpl;
}

/*
 * Lower the task priority level.
 *
 * This function implements the RestoreTpl service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @old_tpl     value of the task priority level to be restored
 */
static void EFIAPI efi_restore_tpl(efi_uintn_t old_tpl)
{
        EFI_ENTRY("0x%zx", old_tpl);

        if (old_tpl > efi_tpl)
                debug("WARNING: old_tpl > current_tpl in %s\n", __func__);
        efi_tpl = old_tpl;
        if (efi_tpl > TPL_HIGH_LEVEL)
                efi_tpl = TPL_HIGH_LEVEL;

        /*
         * Lowering the TPL may have made queued events eligible for execution.
         */
        efi_timer_check();

        EFI_EXIT(EFI_SUCCESS);
}

/*
 * Allocate memory pages.
 *
 * This function implements the AllocatePages service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @type                type of allocation to be performed
 * @memory_type         usage type of the allocated memory
 * @pages               number of pages to be allocated
 * @memory              allocated memory
 * @return              status code
 */
static efi_status_t EFIAPI efi_allocate_pages_ext(int type, int memory_type,
                                                  efi_uintn_t pages,
                                                  uint64_t *memory)
{
        efi_status_t r;

        EFI_ENTRY("%d, %d, 0x%zx, %p", type, memory_type, pages, memory);
        r = efi_allocate_pages(type, memory_type, pages, memory);
        return EFI_EXIT(r);
}

/*
 * Free memory pages.
 *
 * This function implements the FreePages service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @memory      start of the memory area to be freed
 * @pages       number of pages to be freed
 * @return      status code
 */
static efi_status_t EFIAPI efi_free_pages_ext(uint64_t memory,
                                              efi_uintn_t pages)
{
        efi_status_t r;

        EFI_ENTRY("%" PRIx64 ", 0x%zx", memory, pages);
        r = efi_free_pages(memory, pages);
        return EFI_EXIT(r);
}

/*
 * Get map describing memory usage.
 *
 * This function implements the GetMemoryMap service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @memory_map_size     on entry the size, in bytes, of the memory map buffer,
 *                      on exit the size of the copied memory map
 * @memory_map          buffer to which the memory map is written
 * @map_key             key for the memory map
 * @descriptor_size     size of an individual memory descriptor
 * @descriptor_version  version number of the memory descriptor structure
 * @return              status code
 */
static efi_status_t EFIAPI efi_get_memory_map_ext(
                                        efi_uintn_t *memory_map_size,
                                        struct efi_mem_desc *memory_map,
                                        efi_uintn_t *map_key,
                                        efi_uintn_t *descriptor_size,
                                        uint32_t *descriptor_version)
{
        efi_status_t r;

        EFI_ENTRY("%p, %p, %p, %p, %p", memory_map_size, memory_map,
                  map_key, descriptor_size, descriptor_version);
        r = efi_get_memory_map(memory_map_size, memory_map, map_key,
                               descriptor_size, descriptor_version);
        return EFI_EXIT(r);
}

/*
 * Allocate memory from pool.
 *
 * This function implements the AllocatePool service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @pool_type   type of the pool from which memory is to be allocated
 * @size        number of bytes to be allocated
 * @buffer      allocated memory
 * @return      status code
 */
static efi_status_t EFIAPI efi_allocate_pool_ext(int pool_type,
                                                 efi_uintn_t size,
                                                 void **buffer)
{
        efi_status_t r;

        EFI_ENTRY("%d, %zd, %p", pool_type, size, buffer);
        r = efi_allocate_pool(pool_type, size, buffer);
        return EFI_EXIT(r);
}

/*
 * Free memory from pool.
 *
 * This function implements the FreePool service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @buffer      start of memory to be freed
 * @return      status code
 */
static efi_status_t EFIAPI efi_free_pool_ext(void *buffer)
{
        efi_status_t r;

        EFI_ENTRY("%p", buffer);
        r = efi_free_pool(buffer);
        return EFI_EXIT(r);
}

/*
 * Add a new object to the object list.
 *
 * The protocols list is initialized.
 * The object handle is set.
 *
 * @obj object to be added
 */
void efi_add_handle(struct efi_object *obj)
{
        if (!obj)
                return;
        INIT_LIST_HEAD(&obj->protocols);
        obj->handle = obj;
        list_add_tail(&obj->link, &efi_obj_list);
}

/*
 * Create handle.
 *
 * @handle      new handle
 * @return      status code
 */
efi_status_t efi_create_handle(efi_handle_t *handle)
{
        struct efi_object *obj;
        efi_status_t r;

        r = efi_allocate_pool(EFI_ALLOCATE_ANY_PAGES,
                              sizeof(struct efi_object),
                              (void **)&obj);
        if (r != EFI_SUCCESS)
                return r;
        efi_add_handle(obj);
        *handle = obj->handle;
        return r;
}

/*
 * Find a protocol on a handle.
 *
 * @handle              handle
 * @protocol_guid       GUID of the protocol
 * @handler             reference to the protocol
 * @return              status code
 */
efi_status_t efi_search_protocol(const efi_handle_t handle,
                                 const efi_guid_t *protocol_guid,
                                 struct efi_handler **handler)
{
        struct efi_object *efiobj;
        struct list_head *lhandle;

        if (!handle || !protocol_guid)
                return EFI_INVALID_PARAMETER;
        efiobj = efi_search_obj(handle);
        if (!efiobj)
                return EFI_INVALID_PARAMETER;
        list_for_each(lhandle, &efiobj->protocols) {
                struct efi_handler *protocol;

                protocol = list_entry(lhandle, struct efi_handler, link);
                if (!guidcmp(protocol->guid, protocol_guid)) {
                        if (handler)
                                *handler = protocol;
                        return EFI_SUCCESS;
                }
        }
        return EFI_NOT_FOUND;
}

/*
 * Delete protocol from a handle.
 *
 * @handle                      handle from which the protocol shall be deleted
 * @protocol                    GUID of the protocol to be deleted
 * @protocol_interface          interface of the protocol implementation
 * @return                      status code
 */
efi_status_t efi_remove_protocol(const efi_handle_t handle,
                                 const efi_guid_t *protocol,
                                 void *protocol_interface)
{
        struct efi_handler *handler;
        efi_status_t ret;

        ret = efi_search_protocol(handle, protocol, &handler);
        if (ret != EFI_SUCCESS)
                return ret;
        if (guidcmp(handler->guid, protocol))
                return EFI_INVALID_PARAMETER;
        if (handler->protocol_interface != protocol_interface)
                return EFI_INVALID_PARAMETER;
        list_del(&handler->link);
        free(handler);
        return EFI_SUCCESS;
}

/*
 * Delete all protocols from a handle.
 *
 * @handle      handle from which the protocols shall be deleted
 * @return      status code
 */
efi_status_t efi_remove_all_protocols(const efi_handle_t handle)
{
        struct efi_object *efiobj;
        struct efi_handler *protocol;
        struct efi_handler *pos;

        efiobj = efi_search_obj(handle);
        if (!efiobj)
                return EFI_INVALID_PARAMETER;
        list_for_each_entry_safe(protocol, pos, &efiobj->protocols, link) {
                efi_status_t ret;

                ret = efi_remove_protocol(handle, protocol->guid,
                                          protocol->protocol_interface);
                if (ret != EFI_SUCCESS)
                        return ret;
        }
        return EFI_SUCCESS;
}

/*
 * Delete handle.
 *
 * @handle      handle to delete
 */
void efi_delete_handle(struct efi_object *obj)
{
        if (!obj)
                return;
        efi_remove_all_protocols(obj->handle);
        list_del(&obj->link);
        free(obj);
}

/*
 * Check if a pointer is a valid event.
 *
 * @event               pointer to check
 * @return              status code
 */
static efi_status_t efi_is_event(const struct efi_event *event)
{
        const struct efi_event *evt;

        if (!event)
                return EFI_INVALID_PARAMETER;
        list_for_each_entry(evt, &efi_events, link) {
                if (evt == event)
                        return EFI_SUCCESS;
        }
        return EFI_INVALID_PARAMETER;
}

/*
 * Create an event.
 *
 * This function is used inside U-Boot code to create an event.
 *
 * For the API function implementing the CreateEvent service see
 * efi_create_event_ext.
 *
 * @type                type of the event to create
 * @notify_tpl          task priority level of the event
 * @notify_function     notification function of the event
 * @notify_context      pointer passed to the notification function
 * @event               created event
 * @return              status code
 */
efi_status_t efi_create_event(uint32_t type, efi_uintn_t notify_tpl,
                              void (EFIAPI *notify_function) (
                                        struct efi_event *event,
                                        void *context),
                              void *notify_context, efi_guid_t *group,
                              struct efi_event **event)
{
        struct efi_event *evt;

        if (event == NULL)
                return EFI_INVALID_PARAMETER;

        if ((type & EVT_NOTIFY_SIGNAL) && (type & EVT_NOTIFY_WAIT))
                return EFI_INVALID_PARAMETER;

        if ((type & (EVT_NOTIFY_SIGNAL | EVT_NOTIFY_WAIT)) &&
            notify_function == NULL)
                return EFI_INVALID_PARAMETER;

        evt = calloc(1, sizeof(struct efi_event));
        if (!evt)
                return EFI_OUT_OF_RESOURCES;
        evt->type = type;
        evt->notify_tpl = notify_tpl;
        evt->notify_function = notify_function;
        evt->notify_context = notify_context;
        evt->group = group;
        /* Disable timers on bootup */
        evt->trigger_next = -1ULL;
        evt->is_queued = false;
        evt->is_signaled = false;
        list_add_tail(&evt->link, &efi_events);
        *event = evt;
        return EFI_SUCCESS;
}

/*
 * Create an event in a group.
 *
 * This function implements the CreateEventEx service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 * TODO: Support event groups
 *
 * @type                type of the event to create
 * @notify_tpl          task priority level of the event
 * @notify_function     notification function of the event
 * @notify_context      pointer passed to the notification function
 * @event               created event
 * @event_group         event group
 * @return              status code
 */
efi_status_t EFIAPI efi_create_event_ex(uint32_t type, efi_uintn_t notify_tpl,
                                        void (EFIAPI *notify_function) (
                                                        struct efi_event *event,
                                                        void *context),
                                        void *notify_context,
                                        efi_guid_t *event_group,
                                        struct efi_event **event)
{
        EFI_ENTRY("%d, 0x%zx, %p, %p, %pUl", type, notify_tpl, notify_function,
                  notify_context, event_group);
        return EFI_EXIT(efi_create_event(type, notify_tpl, notify_function,
                                         notify_context, event_group, event));
}

/*
 * Create an event.
 *
 * This function implements the CreateEvent service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @type                type of the event to create
 * @notify_tpl          task priority level of the event
 * @notify_function     notification function of the event
 * @notify_context      pointer passed to the notification function
 * @event               created event
 * @return              status code
 */
static efi_status_t EFIAPI efi_create_event_ext(
                        uint32_t type, efi_uintn_t notify_tpl,
                        void (EFIAPI *notify_function) (
                                        struct efi_event *event,
                                        void *context),
                        void *notify_context, struct efi_event **event)
{
        EFI_ENTRY("%d, 0x%zx, %p, %p", type, notify_tpl, notify_function,
                  notify_context);
        return EFI_EXIT(efi_create_event(type, notify_tpl, notify_function,
                                         notify_context, NULL, event));
}

/*
 * Check if a timer event has occurred or a queued notification function should
 * be called.
 *
 * Our timers have to work without interrupts, so we check whenever keyboard
 * input or disk accesses happen if enough time elapsed for them to fire.
 */
void efi_timer_check(void)
{
        struct efi_event *evt;
        u64 now = timer_get_us();

        list_for_each_entry(evt, &efi_events, link) {
                if (evt->is_queued)
                        efi_queue_event(evt, true);
                if (!(evt->type & EVT_TIMER) || now < evt->trigger_next)
                        continue;
                switch (evt->trigger_type) {
                case EFI_TIMER_RELATIVE:
                        evt->trigger_type = EFI_TIMER_STOP;
                        break;
                case EFI_TIMER_PERIODIC:
                        evt->trigger_next += evt->trigger_time;
                        break;
                default:
                        continue;
                }
                evt->is_signaled = false;
                efi_signal_event(evt, true);
        }
        WATCHDOG_RESET();
}

/*
 * Set the trigger time for a timer event or stop the event.
 *
 * This is the function for internal usage in U-Boot. For the API function
 * implementing the SetTimer service see efi_set_timer_ext.
 *
 * @event               event for which the timer is set
 * @type                type of the timer
 * @trigger_time        trigger period in multiples of 100ns
 * @return              status code
 */
efi_status_t efi_set_timer(struct efi_event *event, enum efi_timer_delay type,
                           uint64_t trigger_time)
{
        /* Check that the event is valid */
        if (efi_is_event(event) != EFI_SUCCESS || !(event->type & EVT_TIMER))
                return EFI_INVALID_PARAMETER;

        /*
         * The parameter defines a multiple of 100ns.
         * We use multiples of 1000ns. So divide by 10.
         */
        do_div(trigger_time, 10);

        switch (type) {
        case EFI_TIMER_STOP:
                event->trigger_next = -1ULL;
                break;
        case EFI_TIMER_PERIODIC:
        case EFI_TIMER_RELATIVE:
                event->trigger_next = timer_get_us() + trigger_time;
                break;
        default:
                return EFI_INVALID_PARAMETER;
        }
        event->trigger_type = type;
        event->trigger_time = trigger_time;
        event->is_signaled = false;
        return EFI_SUCCESS;
}

/*
 * Set the trigger time for a timer event or stop the event.
 *
 * This function implements the SetTimer service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @event               event for which the timer is set
 * @type                type of the timer
 * @trigger_time        trigger period in multiples of 100ns
 * @return              status code
 */
static efi_status_t EFIAPI efi_set_timer_ext(struct efi_event *event,
                                             enum efi_timer_delay type,
                                             uint64_t trigger_time)
{
        EFI_ENTRY("%p, %d, %" PRIx64, event, type, trigger_time);
        return EFI_EXIT(efi_set_timer(event, type, trigger_time));
}

/*
 * Wait for events to be signaled.
 *
 * This function implements the WaitForEvent service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @num_events  number of events to be waited for
 * @events      events to be waited for
 * @index       index of the event that was signaled
 * @return      status code
 */
static efi_status_t EFIAPI efi_wait_for_event(efi_uintn_t num_events,
                                              struct efi_event **event,
                                              efi_uintn_t *index)
{
        int i;

        EFI_ENTRY("%zd, %p, %p", num_events, event, index);

        /* Check parameters */
        if (!num_events || !event)
                return EFI_EXIT(EFI_INVALID_PARAMETER);
        /* Check TPL */
        if (efi_tpl != TPL_APPLICATION)
                return EFI_EXIT(EFI_UNSUPPORTED);
        for (i = 0; i < num_events; ++i) {
                if (efi_is_event(event[i]) != EFI_SUCCESS)
                        return EFI_EXIT(EFI_INVALID_PARAMETER);
                if (!event[i]->type || event[i]->type & EVT_NOTIFY_SIGNAL)
                        return EFI_EXIT(EFI_INVALID_PARAMETER);
                if (!event[i]->is_signaled)
                        efi_queue_event(event[i], true);
        }

        /* Wait for signal */
        for (;;) {
                for (i = 0; i < num_events; ++i) {
                        if (event[i]->is_signaled)
                                goto out;
                }
                /* Allow events to occur. */
                efi_timer_check();
        }

out:
        /*
         * Reset the signal which is passed to the caller to allow periodic
         * events to occur.
         */
        event[i]->is_signaled = false;
        if (index)
                *index = i;

        return EFI_EXIT(EFI_SUCCESS);
}

/*
 * Signal an EFI event.
 *
 * This function implements the SignalEvent service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * This functions sets the signaled state of the event and queues the
 * notification function for execution.
 *
 * @event       event to signal
 * @return      status code
 */
static efi_status_t EFIAPI efi_signal_event_ext(struct efi_event *event)
{
        EFI_ENTRY("%p", event);
        if (efi_is_event(event) != EFI_SUCCESS)
                return EFI_EXIT(EFI_INVALID_PARAMETER);
        efi_signal_event(event, true);
        return EFI_EXIT(EFI_SUCCESS);
}

/*
 * Close an EFI event.
 *
 * This function implements the CloseEvent service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @event       event to close
 * @return      status code
 */
static efi_status_t EFIAPI efi_close_event(struct efi_event *event)
{
        EFI_ENTRY("%p", event);
        if (efi_is_event(event) != EFI_SUCCESS)
                return EFI_EXIT(EFI_INVALID_PARAMETER);
        list_del(&event->link);
        free(event);
        return EFI_EXIT(EFI_SUCCESS);
}

/*
 * Check if an event is signaled.
 *
 * This function implements the CheckEvent service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * If an event is not signaled yet, the notification function is queued.
 * The signaled state is cleared.
 *
 * @event       event to check
 * @return      status code
 */
static efi_status_t EFIAPI efi_check_event(struct efi_event *event)
{
        EFI_ENTRY("%p", event);
        efi_timer_check();
        if (efi_is_event(event) != EFI_SUCCESS ||
            event->type & EVT_NOTIFY_SIGNAL)
                return EFI_EXIT(EFI_INVALID_PARAMETER);
        if (!event->is_signaled)
                efi_queue_event(event, true);
        if (event->is_signaled) {
                event->is_signaled = false;
                return EFI_EXIT(EFI_SUCCESS);
        }
        return EFI_EXIT(EFI_NOT_READY);
}

/*
 * Find the internal EFI object for a handle.
 *
 * @handle      handle to find
 * @return      EFI object
 */
struct efi_object *efi_search_obj(const efi_handle_t handle)
{
        struct efi_object *efiobj;

        list_for_each_entry(efiobj, &efi_obj_list, link) {
                if (efiobj->handle == handle)
                        return efiobj;
        }

        return NULL;
}

/*
 * Create open protocol info entry and add it to a protocol.
 *
 * @handler     handler of a protocol
 * @return      open protocol info entry
 */
static struct efi_open_protocol_info_entry *efi_create_open_info(
                        struct efi_handler *handler)
{
        struct efi_open_protocol_info_item *item;

        item = calloc(1, sizeof(struct efi_open_protocol_info_item));
        if (!item)
                return NULL;
        /* Append the item to the open protocol info list. */
        list_add_tail(&item->link, &handler->open_infos);

        return &item->info;
}

/*
 * Remove an open protocol info entry from a protocol.
 *
 * @handler     handler of a protocol
 * @return      status code
 */
static efi_status_t efi_delete_open_info(
                        struct efi_open_protocol_info_item *item)
{
        list_del(&item->link);
        free(item);
        return EFI_SUCCESS;
}

/*
 * Install new protocol on a handle.
 *
 * @handle                      handle on which the protocol shall be installed
 * @protocol                    GUID of the protocol to be installed
 * @protocol_interface          interface of the protocol implementation
 * @return                      status code
 */
efi_status_t efi_add_protocol(const efi_handle_t handle,
                              const efi_guid_t *protocol,
                              void *protocol_interface)
{
        struct efi_object *efiobj;
        struct efi_handler *handler;
        efi_status_t ret;

        efiobj = efi_search_obj(handle);
        if (!efiobj)
                return EFI_INVALID_PARAMETER;
        ret = efi_search_protocol(handle, protocol, NULL);
        if (ret != EFI_NOT_FOUND)
                return EFI_INVALID_PARAMETER;
        handler = calloc(1, sizeof(struct efi_handler));
        if (!handler)
                return EFI_OUT_OF_RESOURCES;
        handler->guid = protocol;
        handler->protocol_interface = protocol_interface;
        INIT_LIST_HEAD(&handler->open_infos);
        list_add_tail(&handler->link, &efiobj->protocols);
        if (!guidcmp(&efi_guid_device_path, protocol))
                EFI_PRINT("installed device path '%pD'\n", protocol_interface);
        return EFI_SUCCESS;
}

/*
 * Install protocol interface.
 *
 * This function implements the InstallProtocolInterface service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @handle                      handle on which the protocol shall be installed
 * @protocol                    GUID of the protocol to be installed
 * @protocol_interface_type     type of the interface to be installed,
 *                              always EFI_NATIVE_INTERFACE
 * @protocol_interface          interface of the protocol implementation
 * @return                      status code
 */
static efi_status_t EFIAPI efi_install_protocol_interface(
                        void **handle, const efi_guid_t *protocol,
                        int protocol_interface_type, void *protocol_interface)
{
        efi_status_t r;

        EFI_ENTRY("%p, %pUl, %d, %p", handle, protocol, protocol_interface_type,
                  protocol_interface);

        if (!handle || !protocol ||
            protocol_interface_type != EFI_NATIVE_INTERFACE) {
                r = EFI_INVALID_PARAMETER;
                goto out;
        }

        /* Create new handle if requested. */
        if (!*handle) {
                r = efi_create_handle(handle);
                if (r != EFI_SUCCESS)
                        goto out;
                debug("%sEFI: new handle %p\n", indent_string(nesting_level),
                      *handle);
        } else {
                debug("%sEFI: handle %p\n", indent_string(nesting_level),
                      *handle);
        }
        /* Add new protocol */
        r = efi_add_protocol(*handle, protocol, protocol_interface);
out:
        return EFI_EXIT(r);
}

/*
 * Get all drivers associated to a controller.
 * The allocated buffer has to be freed with free().
 *
 * @efiobj                      handle of the controller
 * @protocol                    protocol guid (optional)
 * @number_of_drivers           number of child controllers
 * @driver_handle_buffer        handles of the the drivers
 * @return                      status code
 */
static efi_status_t efi_get_drivers(struct efi_object *efiobj,
                                    const efi_guid_t *protocol,
                                    efi_uintn_t *number_of_drivers,
                                    efi_handle_t **driver_handle_buffer)
{
        struct efi_handler *handler;
        struct efi_open_protocol_info_item *item;
        efi_uintn_t count = 0, i;
        bool duplicate;

        /* Count all driver associations */
        list_for_each_entry(handler, &efiobj->protocols, link) {
                if (protocol && guidcmp(handler->guid, protocol))
                        continue;
                list_for_each_entry(item, &handler->open_infos, link) {
                        if (item->info.attributes &
                            EFI_OPEN_PROTOCOL_BY_DRIVER)
                                ++count;
                }
        }
        /*
         * Create buffer. In case of duplicate driver assignments the buffer
         * will be too large. But that does not harm.
         */
        *number_of_drivers = 0;
        *driver_handle_buffer = calloc(count, sizeof(efi_handle_t));
        if (!*driver_handle_buffer)
                return EFI_OUT_OF_RESOURCES;
        /* Collect unique driver handles */
        list_for_each_entry(handler, &efiobj->protocols, link) {
                if (protocol && guidcmp(handler->guid, protocol))
                        continue;
                list_for_each_entry(item, &handler->open_infos, link) {
                        if (item->info.attributes &
                            EFI_OPEN_PROTOCOL_BY_DRIVER) {
                                /* Check this is a new driver */
                                duplicate = false;
                                for (i = 0; i < *number_of_drivers; ++i) {
                                        if ((*driver_handle_buffer)[i] ==
                                            item->info.agent_handle)
                                                duplicate = true;
                                }
                                /* Copy handle to buffer */
                                if (!duplicate) {
                                        i = (*number_of_drivers)++;
                                        (*driver_handle_buffer)[i] =
                                                item->info.agent_handle;
                                }
                        }
                }
        }
        return EFI_SUCCESS;
}

/*
 * Disconnect all drivers from a controller.
 *
 * This function implements the DisconnectController service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @efiobj              handle of the controller
 * @protocol            protocol guid (optional)
 * @child_handle        handle of the child to destroy
 * @return              status code
 */
static efi_status_t efi_disconnect_all_drivers(
                                struct efi_object *efiobj,
                                const efi_guid_t *protocol,
                                efi_handle_t child_handle)
{
        efi_uintn_t number_of_drivers;
        efi_handle_t *driver_handle_buffer;
        efi_status_t r, ret;

        ret = efi_get_drivers(efiobj, protocol, &number_of_drivers,
                              &driver_handle_buffer);
        if (ret != EFI_SUCCESS)
                return ret;

        ret = EFI_NOT_FOUND;
        while (number_of_drivers) {
                r = EFI_CALL(efi_disconnect_controller(
                                efiobj->handle,
                                driver_handle_buffer[--number_of_drivers],
                                child_handle));
                if (r == EFI_SUCCESS)
                        ret = r;
        }
        free(driver_handle_buffer);
        return ret;
}

/*
 * Uninstall protocol interface.
 *
 * This function implements the UninstallProtocolInterface service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @handle                      handle from which the protocol shall be removed
 * @protocol                    GUID of the protocol to be removed
 * @protocol_interface          interface to be removed
 * @return                      status code
 */
static efi_status_t EFIAPI efi_uninstall_protocol_interface(
                                efi_handle_t handle, const efi_guid_t *protocol,
                                void *protocol_interface)
{
        struct efi_object *efiobj;
        struct efi_handler *handler;
        struct efi_open_protocol_info_item *item;
        struct efi_open_protocol_info_item *pos;
        efi_status_t r;

        EFI_ENTRY("%p, %pUl, %p", handle, protocol, protocol_interface);

        /* Check handle */
        efiobj = efi_search_obj(handle);
        if (!efiobj) {
                r = EFI_INVALID_PARAMETER;
                goto out;
        }
        /* Find the protocol on the handle */
        r = efi_search_protocol(handle, protocol, &handler);
        if (r != EFI_SUCCESS)
                goto out;
        /* Disconnect controllers */
        efi_disconnect_all_drivers(efiobj, protocol, NULL);
        if (!list_empty(&handler->open_infos)) {
                r =  EFI_ACCESS_DENIED;
                goto out;
        }
        /* Close protocol */
        list_for_each_entry_safe(item, pos, &handler->open_infos, link) {
                if (item->info.attributes ==
                        EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL ||
                    item->info.attributes == EFI_OPEN_PROTOCOL_GET_PROTOCOL ||
                    item->info.attributes == EFI_OPEN_PROTOCOL_TEST_PROTOCOL)
                        list_del(&item->link);
        }
        if (!list_empty(&handler->open_infos)) {
                r =  EFI_ACCESS_DENIED;
                goto out;
        }
        r = efi_remove_protocol(handle, protocol, protocol_interface);
out:
        return EFI_EXIT(r);
}

/*
 * Register an event for notification when a protocol is installed.
 *
 * This function implements the RegisterProtocolNotify service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @protocol            GUID of the protocol whose installation shall be
 *                      notified
 * @event               event to be signaled upon installation of the protocol
 * @registration        key for retrieving the registration information
 * @return              status code
 */
static efi_status_t EFIAPI efi_register_protocol_notify(
                                                const efi_guid_t *protocol,
                                                struct efi_event *event,
                                                void **registration)
{
        EFI_ENTRY("%pUl, %p, %p", protocol, event, registration);
        return EFI_EXIT(EFI_OUT_OF_RESOURCES);
}

/*
 * Determine if an EFI handle implements a protocol.
 *
 * See the documentation of the LocateHandle service in the UEFI specification.
 *
 * @search_type         selection criterion
 * @protocol            GUID of the protocol
 * @search_key          registration key
 * @efiobj              handle
 * @return              0 if the handle implements the protocol
 */
static int efi_search(enum efi_locate_search_type search_type,
                      const efi_guid_t *protocol, void *search_key,
                      struct efi_object *efiobj)
{
        efi_status_t ret;

        switch (search_type) {
        case ALL_HANDLES:
                return 0;
        case BY_REGISTER_NOTIFY:
                /* TODO: RegisterProtocolNotify is not implemented yet */
                return -1;
        case BY_PROTOCOL:
                ret = efi_search_protocol(efiobj->handle, protocol, NULL);
                return (ret != EFI_SUCCESS);
        default:
                /* Invalid search type */
                return -1;
        }
}

/*
 * Locate handles implementing a protocol.
 *
 * This function is meant for U-Boot internal calls. For the API implementation
 * of the LocateHandle service see efi_locate_handle_ext.
 *
 * @search_type         selection criterion
 * @protocol            GUID of the protocol
 * @search_key          registration key
 * @buffer_size         size of the buffer to receive the handles in bytes
 * @buffer              buffer to receive the relevant handles
 * @return              status code
 */
static efi_status_t efi_locate_handle(
                        enum efi_locate_search_type search_type,
                        const efi_guid_t *protocol, void *search_key,
                        efi_uintn_t *buffer_size, efi_handle_t *buffer)
{
        struct efi_object *efiobj;
        efi_uintn_t size = 0;

        /* Check parameters */
        switch (search_type) {
        case ALL_HANDLES:
                break;
        case BY_REGISTER_NOTIFY:
                if (!search_key)
                        return EFI_INVALID_PARAMETER;
                /* RegisterProtocolNotify is not implemented yet */
                return EFI_UNSUPPORTED;
        case BY_PROTOCOL:
                if (!protocol)
                        return EFI_INVALID_PARAMETER;
                break;
        default:
                return EFI_INVALID_PARAMETER;
        }

        /*
         * efi_locate_handle_buffer uses this function for
         * the calculation of the necessary buffer size.
         * So do not require a buffer for buffersize == 0.
         */
        if (!buffer_size || (*buffer_size && !buffer))
                return EFI_INVALID_PARAMETER;

        /* Count how much space we need */
        list_for_each_entry(efiobj, &efi_obj_list, link) {
                if (!efi_search(search_type, protocol, search_key, efiobj))
                        size += sizeof(void *);
        }

        if (*buffer_size < size) {
                *buffer_size = size;
                return EFI_BUFFER_TOO_SMALL;
        }

        *buffer_size = size;
        if (size == 0)
                return EFI_NOT_FOUND;

        /* Then fill the array */
        list_for_each_entry(efiobj, &efi_obj_list, link) {
                if (!efi_search(search_type, protocol, search_key, efiobj))
                        *buffer++ = efiobj->handle;
        }

        return EFI_SUCCESS;
}

/*
 * Locate handles implementing a protocol.
 *
 * This function implements the LocateHandle service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @search_type         selection criterion
 * @protocol            GUID of the protocol
 * @search_key          registration key
 * @buffer_size         size of the buffer to receive the handles in bytes
 * @buffer              buffer to receive the relevant handles
 * @return              0 if the handle implements the protocol
 */
static efi_status_t EFIAPI efi_locate_handle_ext(
                        enum efi_locate_search_type search_type,
                        const efi_guid_t *protocol, void *search_key,
                        efi_uintn_t *buffer_size, efi_handle_t *buffer)
{
        EFI_ENTRY("%d, %pUl, %p, %p, %p", search_type, protocol, search_key,
                  buffer_size, buffer);

        return EFI_EXIT(efi_locate_handle(search_type, protocol, search_key,
                        buffer_size, buffer));
}

/* Collapses configuration table entries, removing index i */
static void efi_remove_configuration_table(int i)
{
        struct efi_configuration_table *this = &efi_conf_table[i];
        struct efi_configuration_table *next = &efi_conf_table[i + 1];
        struct efi_configuration_table *end = &efi_conf_table[systab.nr_tables];

        memmove(this, next, (ulong)end - (ulong)next);
        systab.nr_tables--;
}

/*
 * Adds, updates, or removes a configuration table.
 *
 * This function is used for internal calls. For the API implementation of the
 * InstallConfigurationTable service see efi_install_configuration_table_ext.
 *
 * @guid                GUID of the installed table
 * @table               table to be installed
 * @return              status code
 */
efi_status_t efi_install_configuration_table(const efi_guid_t *guid,
                                             void *table)
{
        struct efi_event *evt;
        int i;

        if (!guid)
                return EFI_INVALID_PARAMETER;

        /* Check for guid override */
        for (i = 0; i < systab.nr_tables; i++) {
                if (!guidcmp(guid, &efi_conf_table[i].guid)) {
                        if (table)
                                efi_conf_table[i].table = table;
                        else
                                efi_remove_configuration_table(i);
                        goto out;
                }
        }

        if (!table)
                return EFI_NOT_FOUND;

        /* No override, check for overflow */
        if (i >= ARRAY_SIZE(efi_conf_table))
                return EFI_OUT_OF_RESOURCES;

        /* Add a new entry */
        memcpy(&efi_conf_table[i].guid, guid, sizeof(*guid));
        efi_conf_table[i].table = table;
        systab.nr_tables = i + 1;

out:
        /* Notify that the configuration table was changed */
        list_for_each_entry(evt, &efi_events, link) {
                if (evt->group && !guidcmp(evt->group, guid)) {
                        efi_signal_event(evt, false);
                        break;
                }
        }

        return EFI_SUCCESS;
}

/*
 * Adds, updates, or removes a configuration table.
 *
 * This function implements the InstallConfigurationTable service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @guid                GUID of the installed table
 * @table               table to be installed
 * @return              status code
 */
static efi_status_t EFIAPI efi_install_configuration_table_ext(efi_guid_t *guid,
                                                               void *table)
{
        EFI_ENTRY("%pUl, %p", guid, table);
        return EFI_EXIT(efi_install_configuration_table(guid, table));
}

/*
 * Initialize a loaded_image_info + loaded_image_info object with correct
 * protocols, boot-device, etc.
 *
 * @info                loaded image info to be passed to the entry point of the
 *                      image
 * @obj                 internal object associated with the loaded image
 * @device_path         device path of the loaded image
 * @file_path           file path of the loaded image
 * @return              status code
 */
efi_status_t efi_setup_loaded_image(
                        struct efi_loaded_image *info, struct efi_object *obj,
                        struct efi_device_path *device_path,
                        struct efi_device_path *file_path)
{
        efi_status_t ret;

        /* Add internal object to object list */
        efi_add_handle(obj);
        /* efi_exit() assumes that the handle points to the info */
        obj->handle = info;

        info->file_path = file_path;

        if (device_path) {
                info->device_handle = efi_dp_find_obj(device_path, NULL);
                /*
                 * When asking for the device path interface, return
                 * bootefi_device_path
                 */
                ret = efi_add_protocol(obj->handle, &efi_guid_device_path,
                                       device_path);
                if (ret != EFI_SUCCESS)
                        goto failure;
        }

        /*
         * When asking for the loaded_image interface, just
         * return handle which points to loaded_image_info
         */
        ret = efi_add_protocol(obj->handle, &efi_guid_loaded_image, info);
        if (ret != EFI_SUCCESS)
                goto failure;

        ret = efi_add_protocol(obj->handle,
                               &efi_guid_device_path_to_text_protocol,
                               (void *)&efi_device_path_to_text);
        if (ret != EFI_SUCCESS)
                goto failure;

        ret = efi_add_protocol(obj->handle,
                               &efi_guid_device_path_utilities_protocol,
                               (void *)&efi_device_path_utilities);
        if (ret != EFI_SUCCESS)
                goto failure;

        return ret;
failure:
        printf("ERROR: Failure to install protocols for loaded image\n");
        return ret;
}

/*
 * Load an image using a file path.
 *
 * @file_path           the path of the image to load
 * @buffer              buffer containing the loaded image
 * @return              status code
 */
efi_status_t efi_load_image_from_path(struct efi_device_path *file_path,
                                      void **buffer)
{
        struct efi_file_info *info = NULL;
        struct efi_file_handle *f;
        static efi_status_t ret;
        efi_uintn_t bs;

        f = efi_file_from_path(file_path);
        if (!f)
                return EFI_DEVICE_ERROR;

        bs = 0;
        EFI_CALL(ret = f->getinfo(f, (efi_guid_t *)&efi_file_info_guid,
                                  &bs, info));
        if (ret == EFI_BUFFER_TOO_SMALL) {
                info = malloc(bs);
                EFI_CALL(ret = f->getinfo(f, (efi_guid_t *)&efi_file_info_guid,
                                          &bs, info));
        }
        if (ret != EFI_SUCCESS)
                goto error;

        ret = efi_allocate_pool(EFI_LOADER_DATA, info->file_size, buffer);
        if (ret)
                goto error;

        bs = info->file_size;
        EFI_CALL(ret = f->read(f, &bs, *buffer));

error:
        free(info);
        EFI_CALL(f->close(f));

        if (ret != EFI_SUCCESS) {
                efi_free_pool(*buffer);
                *buffer = NULL;
        }

        return ret;
}

/*
 * Load an EFI image into memory.
 *
 * This function implements the LoadImage service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @boot_policy         true for request originating from the boot manager
 * @parent_image        the caller's image handle
 * @file_path           the path of the image to load
 * @source_buffer       memory location from which the image is installed
 * @source_size         size of the memory area from which the image is
 *                      installed
 * @image_handle        handle for the newly installed image
 * @return              status code
 */
static efi_status_t EFIAPI efi_load_image(bool boot_policy,
                                          efi_handle_t parent_image,
                                          struct efi_device_path *file_path,
                                          void *source_buffer,
                                          efi_uintn_t source_size,
                                          efi_handle_t *image_handle)
{
        struct efi_loaded_image *info;
        struct efi_object *obj;
        efi_status_t ret;

        EFI_ENTRY("%d, %p, %pD, %p, %zd, %p", boot_policy, parent_image,
                  file_path, source_buffer, source_size, image_handle);

        if (!image_handle || !parent_image) {
                ret = EFI_INVALID_PARAMETER;
                goto error;
        }

        if (!source_buffer && !file_path) {
                ret = EFI_NOT_FOUND;
                goto error;
        }

        info = calloc(1, sizeof(*info));
        if (!info) {
                ret = EFI_OUT_OF_RESOURCES;
                goto error;
        }
        obj = calloc(1, sizeof(*obj));
        if (!obj) {
                free(info);
                ret = EFI_OUT_OF_RESOURCES;
                goto error;
        }

        if (!source_buffer) {
                struct efi_device_path *dp, *fp;

                ret = efi_load_image_from_path(file_path, &source_buffer);
                if (ret != EFI_SUCCESS)
                        goto failure;
                /*
                 * split file_path which contains both the device and
                 * file parts:
                 */
                efi_dp_split_file_path(file_path, &dp, &fp);
                ret = efi_setup_loaded_image(info, obj, dp, fp);
                if (ret != EFI_SUCCESS)
                        goto failure;
        } else {
                /* In this case, file_path is the "device" path, ie.
                 * something like a HARDWARE_DEVICE:MEMORY_MAPPED
                 */
                ret = efi_setup_loaded_image(info, obj, file_path, NULL);
                if (ret != EFI_SUCCESS)
                        goto failure;
        }
        info->reserved = efi_load_pe(source_buffer, info);
        if (!info->reserved) {
                ret = EFI_UNSUPPORTED;
                goto failure;
        }
        info->system_table = &systab;
        info->parent_handle = parent_image;
        *image_handle = obj->handle;
        return EFI_EXIT(EFI_SUCCESS);
failure:
        free(info);
        efi_delete_handle(obj);
error:
        return EFI_EXIT(ret);
}

/*
 * Call the entry point of an image.
 *
 * This function implements the StartImage service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @image_handle        handle of the image
 * @exit_data_size      size of the buffer
 * @exit_data           buffer to receive the exit data of the called image
 * @return              status code
 */
static efi_status_t EFIAPI efi_start_image(efi_handle_t image_handle,
                                           unsigned long *exit_data_size,
                                           s16 **exit_data)
{
        EFIAPI efi_status_t (*entry)(efi_handle_t image_handle,
                                     struct efi_system_table *st);
        struct efi_loaded_image *info = image_handle;
        efi_status_t ret;

        EFI_ENTRY("%p, %p, %p", image_handle, exit_data_size, exit_data);
        entry = info->reserved;

        efi_is_direct_boot = false;

        /* call the image! */
        if (setjmp(&info->exit_jmp)) {
                /*
                 * We called the entry point of the child image with EFI_CALL
                 * in the lines below. The child image called the Exit() boot
                 * service efi_exit() which executed the long jump that brought
                 * us to the current line. This implies that the second half
                 * of the EFI_CALL macro has not been executed.
                 */
#ifdef CONFIG_ARM
                /*
                 * efi_exit() called efi_restore_gd(). We have to undo this
                 * otherwise __efi_entry_check() will put the wrong value into
                 * app_gd.
                 */
                gd = app_gd;
#endif
                /*
                 * To get ready to call EFI_EXIT below we have to execute the
                 * missed out steps of EFI_CALL.
                 */
                assert(__efi_entry_check());
                debug("%sEFI: %lu returned by started image\n",
                      __efi_nesting_dec(),
                      (unsigned long)((uintptr_t)info->exit_status &
                                      ~EFI_ERROR_MASK));
                return EFI_EXIT(info->exit_status);
        }

        ret = EFI_CALL(entry(image_handle, &systab));

        /*
         * Usually UEFI applications call Exit() instead of returning.
         * But because the world doesn not consist of ponies and unicorns,
         * we're happy to emulate that behavior on behalf of a payload
         * that forgot.
         */
        return EFI_CALL(systab.boottime->exit(image_handle, ret, 0, NULL));
}

/*
 * Leave an EFI application or driver.
 *
 * This function implements the Exit service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @image_handle        handle of the application or driver that is exiting
 * @exit_status         status code
 * @exit_data_size      size of the buffer in bytes
 * @exit_data           buffer with data describing an error
 * @return              status code
 */
static efi_status_t EFIAPI efi_exit(efi_handle_t image_handle,
                                    efi_status_t exit_status,
                                    unsigned long exit_data_size,
                                    int16_t *exit_data)
{
        /*
         * We require that the handle points to the original loaded
         * image protocol interface.
         *
         * For getting the longjmp address this is safer than locating
         * the protocol because the protocol may have been reinstalled
         * pointing to another memory location.
         *
         * TODO: We should call the unload procedure of the loaded
         *       image protocol.
         */
        struct efi_loaded_image *loaded_image_info = (void *)image_handle;

        EFI_ENTRY("%p, %ld, %ld, %p", image_handle, exit_status,
                  exit_data_size, exit_data);

        /* Make sure entry/exit counts for EFI world cross-overs match */
        EFI_EXIT(exit_status);

        /*
         * But longjmp out with the U-Boot gd, not the application's, as
         * the other end is a setjmp call inside EFI context.
         */
        efi_restore_gd();

        loaded_image_info->exit_status = exit_status;
        longjmp(&loaded_image_info->exit_jmp, 1);

        panic("EFI application exited");
}

/*
 * Unload an EFI image.
 *
 * This function implements the UnloadImage service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @image_handle        handle of the image to be unloaded
 * @return              status code
 */
static efi_status_t EFIAPI efi_unload_image(efi_handle_t image_handle)
{
        struct efi_object *efiobj;

        EFI_ENTRY("%p", image_handle);
        efiobj = efi_search_obj(image_handle);
        if (efiobj)
                list_del(&efiobj->link);

        return EFI_EXIT(EFI_SUCCESS);
}

/*
 * Fix up caches for EFI payloads if necessary.
 */
static void efi_exit_caches(void)
{
#if defined(CONFIG_ARM) && !defined(CONFIG_ARM64)
        /*
         * Grub on 32bit ARM needs to have caches disabled before jumping into
         * a zImage, but does not know of all cache layers. Give it a hand.
         */
        if (efi_is_direct_boot)
                cleanup_before_linux();
#endif
}

/*
 * Stop all boot services.
 *
 * This function implements the ExitBootServices service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * All timer events are disabled.
 * For exit boot services events the notification function is called.
 * The boot services are disabled in the system table.
 *
 * @image_handle        handle of the loaded image
 * @map_key             key of the memory map
 * @return              status code
 */
static efi_status_t EFIAPI efi_exit_boot_services(efi_handle_t image_handle,
                                                  unsigned long map_key)
{
        struct efi_event *evt;

        EFI_ENTRY("%p, %ld", image_handle, map_key);

        /* Make sure that notification functions are not called anymore */
        efi_tpl = TPL_HIGH_LEVEL;

        /* Check if ExitBootServices has already been called */
        if (!systab.boottime)
                return EFI_EXIT(EFI_SUCCESS);

        /* Add related events to the event group */
        list_for_each_entry(evt, &efi_events, link) {
                if (evt->type == EVT_SIGNAL_EXIT_BOOT_SERVICES)
                        evt->group = &efi_guid_event_group_exit_boot_services;
        }
        /* Notify that ExitBootServices is invoked. */
        list_for_each_entry(evt, &efi_events, link) {
                if (evt->group &&
                    !guidcmp(evt->group,
                             &efi_guid_event_group_exit_boot_services)) {
                        efi_signal_event(evt, false);
                        break;
                }
        }

        /* TODO Should persist EFI variables here */

        board_quiesce_devices();

        /* Fix up caches for EFI payloads if necessary */
        efi_exit_caches();

        /* This stops all lingering devices */
        bootm_disable_interrupts();

        /* Disable boottime services */
        systab.con_in_handle = NULL;
        systab.con_in = NULL;
        systab.con_out_handle = NULL;
        systab.con_out = NULL;
        systab.stderr_handle = NULL;
        systab.std_err = NULL;
        systab.boottime = NULL;

        /* Recalculate CRC32 */
        systab.hdr.crc32 = 0;
        systab.hdr.crc32 = crc32(0, (const unsigned char *)&systab,
                                 sizeof(struct efi_system_table));

        /* Give the payload some time to boot */
        efi_set_watchdog(0);
        WATCHDOG_RESET();

        return EFI_EXIT(EFI_SUCCESS);
}

/*
 * Get next value of the counter.
 *
 * This function implements the NextMonotonicCount service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @count       returned value of the counter
 * @return      status code
 */
static efi_status_t EFIAPI efi_get_next_monotonic_count(uint64_t *count)
{
        static uint64_t mono;

        EFI_ENTRY("%p", count);
        *count = mono++;
        return EFI_EXIT(EFI_SUCCESS);
}

/*
 * Sleep.
 *
 * This function implements the Stall sercive.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @microseconds        period to sleep in microseconds
 * @return              status code
 */
static efi_status_t EFIAPI efi_stall(unsigned long microseconds)
{
        EFI_ENTRY("%ld", microseconds);
        udelay(microseconds);
        return EFI_EXIT(EFI_SUCCESS);
}

/*
 * Reset the watchdog timer.
 *
 * This function implements the SetWatchdogTimer service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @timeout             seconds before reset by watchdog
 * @watchdog_code       code to be logged when resetting
 * @data_size           size of buffer in bytes
 * @watchdog_data       buffer with data describing the reset reason
 * @return              status code
 */
static efi_status_t EFIAPI efi_set_watchdog_timer(unsigned long timeout,
                                                  uint64_t watchdog_code,
                                                  unsigned long data_size,
                                                  uint16_t *watchdog_data)
{
        EFI_ENTRY("%ld, 0x%" PRIx64 ", %ld, %p", timeout, watchdog_code,
                  data_size, watchdog_data);
        return EFI_EXIT(efi_set_watchdog(timeout));
}

/*
 * Close a protocol.
 *
 * This function implements the CloseProtocol service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @handle              handle on which the protocol shall be closed
 * @protocol            GUID of the protocol to close
 * @agent_handle        handle of the driver
 * @controller_handle   handle of the controller
 * @return              status code
 */
static efi_status_t EFIAPI efi_close_protocol(efi_handle_t handle,
                                              const efi_guid_t *protocol,
                                              efi_handle_t agent_handle,
                                              efi_handle_t controller_handle)
{
        struct efi_handler *handler;
        struct efi_open_protocol_info_item *item;
        struct efi_open_protocol_info_item *pos;
        efi_status_t r;

        EFI_ENTRY("%p, %pUl, %p, %p", handle, protocol, agent_handle,
                  controller_handle);

        if (!agent_handle) {
                r = EFI_INVALID_PARAMETER;
                goto out;
        }
        r = efi_search_protocol(handle, protocol, &handler);
        if (r != EFI_SUCCESS)
                goto out;

        r = EFI_NOT_FOUND;
        list_for_each_entry_safe(item, pos, &handler->open_infos, link) {
                if (item->info.agent_handle == agent_handle &&
                    item->info.controller_handle == controller_handle) {
                        efi_delete_open_info(item);
                        r = EFI_SUCCESS;
                        break;
                }
        }
out:
        return EFI_EXIT(r);
}

/*
 * Provide information about then open status of a protocol on a handle
 *
 * This function implements the OpenProtocolInformation service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @handle              handle for which the information shall be retrieved
 * @protocol            GUID of the protocol
 * @entry_buffer        buffer to receive the open protocol information
 * @entry_count         number of entries available in the buffer
 * @return              status code
 */
static efi_status_t EFIAPI efi_open_protocol_information(
                        efi_handle_t handle, const efi_guid_t *protocol,
                        struct efi_open_protocol_info_entry **entry_buffer,
                        efi_uintn_t *entry_count)
{
        unsigned long buffer_size;
        unsigned long count;
        struct efi_handler *handler;
        struct efi_open_protocol_info_item *item;
        efi_status_t r;

        EFI_ENTRY("%p, %pUl, %p, %p", handle, protocol, entry_buffer,
                  entry_count);

        /* Check parameters */
        if (!entry_buffer) {
                r = EFI_INVALID_PARAMETER;
                goto out;
        }
        r = efi_search_protocol(handle, protocol, &handler);
        if (r != EFI_SUCCESS)
                goto out;

        /* Count entries */
        count = 0;
        list_for_each_entry(item, &handler->open_infos, link) {
                if (item->info.open_count)
                        ++count;
        }
        *entry_count = count;
        *entry_buffer = NULL;
        if (!count) {
                r = EFI_SUCCESS;
                goto out;
        }

        /* Copy entries */
        buffer_size = count * sizeof(struct efi_open_protocol_info_entry);
        r = efi_allocate_pool(EFI_ALLOCATE_ANY_PAGES, buffer_size,
                              (void **)entry_buffer);
        if (r != EFI_SUCCESS)
                goto out;
        list_for_each_entry_reverse(item, &handler->open_infos, link) {
                if (item->info.open_count)
                        (*entry_buffer)[--count] = item->info;
        }
out:
        return EFI_EXIT(r);
}

/*
 * Get protocols installed on a handle.
 *
 * This function implements the ProtocolsPerHandleService.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @handle                      handle for which the information is retrieved
 * @protocol_buffer             buffer with protocol GUIDs
 * @protocol_buffer_count       number of entries in the buffer
 * @return                      status code
 */
static efi_status_t EFIAPI efi_protocols_per_handle(
                        efi_handle_t handle, efi_guid_t ***protocol_buffer,
                        efi_uintn_t *protocol_buffer_count)
{
        unsigned long buffer_size;
        struct efi_object *efiobj;
        struct list_head *protocol_handle;
        efi_status_t r;

        EFI_ENTRY("%p, %p, %p", handle, protocol_buffer,
                  protocol_buffer_count);

        if (!handle || !protocol_buffer || !protocol_buffer_count)
                return EFI_EXIT(EFI_INVALID_PARAMETER);

        *protocol_buffer = NULL;
        *protocol_buffer_count = 0;

        efiobj = efi_search_obj(handle);
        if (!efiobj)
                return EFI_EXIT(EFI_INVALID_PARAMETER);

        /* Count protocols */
        list_for_each(protocol_handle, &efiobj->protocols) {
                ++*protocol_buffer_count;
        }

        /* Copy guids */
        if (*protocol_buffer_count) {
                size_t j = 0;

                buffer_size = sizeof(efi_guid_t *) * *protocol_buffer_count;
                r = efi_allocate_pool(EFI_ALLOCATE_ANY_PAGES, buffer_size,
                                      (void **)protocol_buffer);
                if (r != EFI_SUCCESS)
                        return EFI_EXIT(r);
                list_for_each(protocol_handle, &efiobj->protocols) {
                        struct efi_handler *protocol;

                        protocol = list_entry(protocol_handle,
                                              struct efi_handler, link);
                        (*protocol_buffer)[j] = (void *)protocol->guid;
                        ++j;
                }
        }

        return EFI_EXIT(EFI_SUCCESS);
}

/*
 * Locate handles implementing a protocol.
 *
 * This function implements the LocateHandleBuffer service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @search_type         selection criterion
 * @protocol            GUID of the protocol
 * @search_key          registration key
 * @no_handles          number of returned handles
 * @buffer              buffer with the returned handles
 * @return              status code
 */
static efi_status_t EFIAPI efi_locate_handle_buffer(
                        enum efi_locate_search_type search_type,
                        const efi_guid_t *protocol, void *search_key,
                        efi_uintn_t *no_handles, efi_handle_t **buffer)
{
        efi_status_t r;
        efi_uintn_t buffer_size = 0;

        EFI_ENTRY("%d, %pUl, %p, %p, %p", search_type, protocol, search_key,
                  no_handles, buffer);

        if (!no_handles || !buffer) {
                r = EFI_INVALID_PARAMETER;
                goto out;
        }
        *no_handles = 0;
        *buffer = NULL;
        r = efi_locate_handle(search_type, protocol, search_key, &buffer_size,
                              *buffer);
        if (r != EFI_BUFFER_TOO_SMALL)
                goto out;
        r = efi_allocate_pool(EFI_ALLOCATE_ANY_PAGES, buffer_size,
                              (void **)buffer);
        if (r != EFI_SUCCESS)
                goto out;
        r = efi_locate_handle(search_type, protocol, search_key, &buffer_size,
                              *buffer);
        if (r == EFI_SUCCESS)
                *no_handles = buffer_size / sizeof(efi_handle_t);
out:
        return EFI_EXIT(r);
}

/*
 * Find an interface implementing a protocol.
 *
 * This function implements the LocateProtocol service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @protocol            GUID of the protocol
 * @registration        registration key passed to the notification function
 * @protocol_interface  interface implementing the protocol
 * @return              status code
 */
static efi_status_t EFIAPI efi_locate_protocol(const efi_guid_t *protocol,
                                               void *registration,
                                               void **protocol_interface)
{
        struct list_head *lhandle;
        efi_status_t ret;

        EFI_ENTRY("%pUl, %p, %p", protocol, registration, protocol_interface);

        if (!protocol || !protocol_interface)
                return EFI_EXIT(EFI_INVALID_PARAMETER);

        list_for_each(lhandle, &efi_obj_list) {
                struct efi_object *efiobj;
                struct efi_handler *handler;

                efiobj = list_entry(lhandle, struct efi_object, link);

                ret = efi_search_protocol(efiobj->handle, protocol, &handler);
                if (ret == EFI_SUCCESS) {
                        *protocol_interface = handler->protocol_interface;
                        return EFI_EXIT(EFI_SUCCESS);
                }
        }
        *protocol_interface = NULL;

        return EFI_EXIT(EFI_NOT_FOUND);
}

/*
 * Get the device path and handle of an device implementing a protocol.
 *
 * This function implements the LocateDevicePath service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @protocol            GUID of the protocol
 * @device_path         device path
 * @device              handle of the device
 * @return              status code
 */
static efi_status_t EFIAPI efi_locate_device_path(
                        const efi_guid_t *protocol,
                        struct efi_device_path **device_path,
                        efi_handle_t *device)
{
        struct efi_device_path *dp;
        size_t i;
        struct efi_handler *handler;
        efi_handle_t *handles;
        size_t len, len_dp;
        size_t len_best = 0;
        efi_uintn_t no_handles;
        u8 *remainder;
        efi_status_t ret;

        EFI_ENTRY("%pUl, %p, %p", protocol, device_path, device);

        if (!protocol || !device_path || !*device_path || !device) {
                ret = EFI_INVALID_PARAMETER;
                goto out;
        }

        /* Find end of device path */
        len = efi_dp_instance_size(*device_path);

        /* Get all handles implementing the protocol */
        ret = EFI_CALL(efi_locate_handle_buffer(BY_PROTOCOL, protocol, NULL,
                                                &no_handles, &handles));
        if (ret != EFI_SUCCESS)
                goto out;

        for (i = 0; i < no_handles; ++i) {
                /* Find the device path protocol */
                ret = efi_search_protocol(handles[i], &efi_guid_device_path,
                                          &handler);
                if (ret != EFI_SUCCESS)
                        continue;
                dp = (struct efi_device_path *)handler->protocol_interface;
                len_dp = efi_dp_instance_size(dp);
                /*
                 * This handle can only be a better fit
                 * if its device path length is longer than the best fit and
                 * if its device path length is shorter of equal the searched
                 * device path.
                 */
                if (len_dp <= len_best || len_dp > len)
                        continue;
                /* Check if dp is a subpath of device_path */
                if (memcmp(*device_path, dp, len_dp))
                        continue;
                *device = handles[i];
                len_best = len_dp;
        }
        if (len_best) {
                remainder = (u8 *)*device_path + len_best;
                *device_path = (struct efi_device_path *)remainder;
                ret = EFI_SUCCESS;
        } else {
                ret = EFI_NOT_FOUND;
        }
out:
        return EFI_EXIT(ret);
}

/*
 * Install multiple protocol interfaces.
 *
 * This function implements the MultipleProtocolInterfaces service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @handle      handle on which the protocol interfaces shall be installed
 * @...         NULL terminated argument list with pairs of protocol GUIDS and
 *              interfaces
 * @return      status code
 */
static efi_status_t EFIAPI efi_install_multiple_protocol_interfaces(
                        void **handle, ...)
{
        EFI_ENTRY("%p", handle);

        va_list argptr;
        const efi_guid_t *protocol;
        void *protocol_interface;
        efi_status_t r = EFI_SUCCESS;
        int i = 0;

        if (!handle)
                return EFI_EXIT(EFI_INVALID_PARAMETER);

        va_start(argptr, handle);
        for (;;) {
                protocol = va_arg(argptr, efi_guid_t*);
                if (!protocol)
                        break;
                protocol_interface = va_arg(argptr, void*);
                r = EFI_CALL(efi_install_protocol_interface(
                                                handle, protocol,
                                                EFI_NATIVE_INTERFACE,
                                                protocol_interface));
                if (r != EFI_SUCCESS)
                        break;
                i++;
        }
        va_end(argptr);
        if (r == EFI_SUCCESS)
                return EFI_EXIT(r);

        /* If an error occurred undo all changes. */
        va_start(argptr, handle);
        for (; i; --i) {
                protocol = va_arg(argptr, efi_guid_t*);
                protocol_interface = va_arg(argptr, void*);
                EFI_CALL(efi_uninstall_protocol_interface(handle, protocol,
                                                          protocol_interface));
        }
        va_end(argptr);

        return EFI_EXIT(r);
}

/*
 * Uninstall multiple protocol interfaces.
 *
 * This function implements the UninstallMultipleProtocolInterfaces service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @handle      handle from which the protocol interfaces shall be removed
 * @...         NULL terminated argument list with pairs of protocol GUIDS and
 *              interfaces
 * @return      status code
 */
static efi_status_t EFIAPI efi_uninstall_multiple_protocol_interfaces(
                        void *handle, ...)
{
        EFI_ENTRY("%p", handle);

        va_list argptr;
        const efi_guid_t *protocol;
        void *protocol_interface;
        efi_status_t r = EFI_SUCCESS;
        size_t i = 0;

        if (!handle)
                return EFI_EXIT(EFI_INVALID_PARAMETER);

        va_start(argptr, handle);
        for (;;) {
                protocol = va_arg(argptr, efi_guid_t*);
                if (!protocol)
                        break;
                protocol_interface = va_arg(argptr, void*);
                r = EFI_CALL(efi_uninstall_protocol_interface(
                                                handle, protocol,
                                                protocol_interface));
                if (r != EFI_SUCCESS)
                        break;
                i++;
        }
        va_end(argptr);
        if (r == EFI_SUCCESS)
                return EFI_EXIT(r);

        /* If an error occurred undo all changes. */
        va_start(argptr, handle);
        for (; i; --i) {
                protocol = va_arg(argptr, efi_guid_t*);
                protocol_interface = va_arg(argptr, void*);
                EFI_CALL(efi_install_protocol_interface(&handle, protocol,
                                                        EFI_NATIVE_INTERFACE,
                                                        protocol_interface));
        }
        va_end(argptr);

        return EFI_EXIT(r);
}

/*
 * Calculate cyclic redundancy code.
 *
 * This function implements the CalculateCrc32 service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @data        buffer with data
 * @data_size   size of buffer in bytes
 * @crc32_p     cyclic redundancy code
 * @return      status code
 */
static efi_status_t EFIAPI efi_calculate_crc32(void *data,
                                               unsigned long data_size,
                                               uint32_t *crc32_p)
{
        EFI_ENTRY("%p, %ld", data, data_size);
        *crc32_p = crc32(0, data, data_size);
        return EFI_EXIT(EFI_SUCCESS);
}

/*
 * Copy memory.
 *
 * This function implements the CopyMem service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @destination         destination of the copy operation
 * @source              source of the copy operation
 * @length              number of bytes to copy
 */
static void EFIAPI efi_copy_mem(void *destination, const void *source,
                                size_t length)
{
        EFI_ENTRY("%p, %p, %ld", destination, source, (unsigned long)length);
        memcpy(destination, source, length);
        EFI_EXIT(EFI_SUCCESS);
}

/*
 * Fill memory with a byte value.
 *
 * This function implements the SetMem service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @buffer              buffer to fill
 * @size                size of buffer in bytes
 * @value               byte to copy to the buffer
 */
static void EFIAPI efi_set_mem(void *buffer, size_t size, uint8_t value)
{
        EFI_ENTRY("%p, %ld, 0x%x", buffer, (unsigned long)size, value);
        memset(buffer, value, size);
        EFI_EXIT(EFI_SUCCESS);
}

/*
 * Open protocol interface on a handle.
 *
 * @handler             handler of a protocol
 * @protocol_interface  interface implementing the protocol
 * @agent_handle        handle of the driver
 * @controller_handle   handle of the controller
 * @attributes          attributes indicating how to open the protocol
 * @return              status code
 */
static efi_status_t efi_protocol_open(
                        struct efi_handler *handler,
                        void **protocol_interface, void *agent_handle,
                        void *controller_handle, uint32_t attributes)
{
        struct efi_open_protocol_info_item *item;
        struct efi_open_protocol_info_entry *match = NULL;
        bool opened_by_driver = false;
        bool opened_exclusive = false;

        /* If there is no agent, only return the interface */
        if (!agent_handle)
                goto out;

        /* For TEST_PROTOCOL ignore interface attribute */
        if (attributes != EFI_OPEN_PROTOCOL_TEST_PROTOCOL)
                *protocol_interface = NULL;

        /*
         * Check if the protocol is already opened by a driver with the same
         * attributes or opened exclusively
         */
        list_for_each_entry(item, &handler->open_infos, link) {
                if (item->info.agent_handle == agent_handle) {
                        if ((attributes & EFI_OPEN_PROTOCOL_BY_DRIVER) &&
                            (item->info.attributes == attributes))
                                return EFI_ALREADY_STARTED;
                }
                if (item->info.attributes & EFI_OPEN_PROTOCOL_EXCLUSIVE)
                        opened_exclusive = true;
        }

        /* Only one controller can open the protocol exclusively */
        if (opened_exclusive && attributes &
            (EFI_OPEN_PROTOCOL_EXCLUSIVE | EFI_OPEN_PROTOCOL_BY_DRIVER))
                return EFI_ACCESS_DENIED;

        /* Prepare exclusive opening */
        if (attributes & EFI_OPEN_PROTOCOL_EXCLUSIVE) {
                /* Try to disconnect controllers */
                list_for_each_entry(item, &handler->open_infos, link) {
                        if (item->info.attributes ==
                                        EFI_OPEN_PROTOCOL_BY_DRIVER)
                                EFI_CALL(efi_disconnect_controller(
                                                item->info.controller_handle,
                                                item->info.agent_handle,
                                                NULL));
                }
                opened_by_driver = false;
                /* Check if all controllers are disconnected */
                list_for_each_entry(item, &handler->open_infos, link) {
                        if (item->info.attributes & EFI_OPEN_PROTOCOL_BY_DRIVER)
                                opened_by_driver = true;
                }
                /* Only one controller can be conncected */
                if (opened_by_driver)
                        return EFI_ACCESS_DENIED;
        }

        /* Find existing entry */
        list_for_each_entry(item, &handler->open_infos, link) {
                if (item->info.agent_handle == agent_handle &&
                    item->info.controller_handle == controller_handle)
                        match = &item->info;
        }
        /* None found, create one */
        if (!match) {
                match = efi_create_open_info(handler);
                if (!match)
                        return EFI_OUT_OF_RESOURCES;
        }

        match->agent_handle = agent_handle;
        match->controller_handle = controller_handle;
        match->attributes = attributes;
        match->open_count++;

out:
        /* For TEST_PROTOCOL ignore interface attribute. */
        if (attributes != EFI_OPEN_PROTOCOL_TEST_PROTOCOL)
                *protocol_interface = handler->protocol_interface;

        return EFI_SUCCESS;
}

/*
 * Open protocol interface on a handle.
 *
 * This function implements the OpenProtocol interface.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @handle              handle on which the protocol shall be opened
 * @protocol            GUID of the protocol
 * @protocol_interface  interface implementing the protocol
 * @agent_handle        handle of the driver
 * @controller_handle   handle of the controller
 * @attributes          attributes indicating how to open the protocol
 * @return              status code
 */
static efi_status_t EFIAPI efi_open_protocol(
                        void *handle, const efi_guid_t *protocol,
                        void **protocol_interface, void *agent_handle,
                        void *controller_handle, uint32_t attributes)
{
        struct efi_handler *handler;
        efi_status_t r = EFI_INVALID_PARAMETER;

        EFI_ENTRY("%p, %pUl, %p, %p, %p, 0x%x", handle, protocol,
                  protocol_interface, agent_handle, controller_handle,
                  attributes);

        if (!handle || !protocol ||
            (!protocol_interface && attributes !=
             EFI_OPEN_PROTOCOL_TEST_PROTOCOL)) {
                goto out;
        }

        switch (attributes) {
        case EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL:
        case EFI_OPEN_PROTOCOL_GET_PROTOCOL:
        case EFI_OPEN_PROTOCOL_TEST_PROTOCOL:
                break;
        case EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER:
                if (controller_handle == handle)
                        goto out;
                /* fall-through */
        case EFI_OPEN_PROTOCOL_BY_DRIVER:
        case EFI_OPEN_PROTOCOL_BY_DRIVER | EFI_OPEN_PROTOCOL_EXCLUSIVE:
                /* Check that the controller handle is valid */
                if (!efi_search_obj(controller_handle))
                        goto out;
                /* fall-through */
        case EFI_OPEN_PROTOCOL_EXCLUSIVE:
                /* Check that the agent handle is valid */
                if (!efi_search_obj(agent_handle))
                        goto out;
                break;
        default:
                goto out;
        }

        r = efi_search_protocol(handle, protocol, &handler);
        if (r != EFI_SUCCESS)
                goto out;

        r = efi_protocol_open(handler, protocol_interface, agent_handle,
                              controller_handle, attributes);
out:
        return EFI_EXIT(r);
}

/*
 * Get interface of a protocol on a handle.
 *
 * This function implements the HandleProtocol service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @handle              handle on which the protocol shall be opened
 * @protocol            GUID of the protocol
 * @protocol_interface  interface implementing the protocol
 * @return              status code
 */
static efi_status_t EFIAPI efi_handle_protocol(efi_handle_t handle,
                                               const efi_guid_t *protocol,
                                               void **protocol_interface)
{
        return efi_open_protocol(handle, protocol, protocol_interface, NULL,
                                 NULL, EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL);
}

static efi_status_t efi_bind_controller(
                        efi_handle_t controller_handle,
                        efi_handle_t driver_image_handle,
                        struct efi_device_path *remain_device_path)
{
        struct efi_driver_binding_protocol *binding_protocol;
        efi_status_t r;

        r = EFI_CALL(efi_open_protocol(driver_image_handle,
                                       &efi_guid_driver_binding_protocol,
                                       (void **)&binding_protocol,
                                       driver_image_handle, NULL,
                                       EFI_OPEN_PROTOCOL_GET_PROTOCOL));
        if (r != EFI_SUCCESS)
                return r;
        r = EFI_CALL(binding_protocol->supported(binding_protocol,
                                                 controller_handle,
                                                 remain_device_path));
        if (r == EFI_SUCCESS)
                r = EFI_CALL(binding_protocol->start(binding_protocol,
                                                     controller_handle,
                                                     remain_device_path));
        EFI_CALL(efi_close_protocol(driver_image_handle,
                                    &efi_guid_driver_binding_protocol,
                                    driver_image_handle, NULL));
        return r;
}

static efi_status_t efi_connect_single_controller(
                        efi_handle_t controller_handle,
                        efi_handle_t *driver_image_handle,
                        struct efi_device_path *remain_device_path)
{
        efi_handle_t *buffer;
        size_t count;
        size_t i;
        efi_status_t r;
        size_t connected = 0;

        /* Get buffer with all handles with driver binding protocol */
        r = EFI_CALL(efi_locate_handle_buffer(BY_PROTOCOL,
                                              &efi_guid_driver_binding_protocol,
                                              NULL, &count, &buffer));
        if (r != EFI_SUCCESS)
                return r;

        /*  Context Override */
        if (driver_image_handle) {
                for (; *driver_image_handle; ++driver_image_handle) {
                        for (i = 0; i < count; ++i) {
                                if (buffer[i] == *driver_image_handle) {
                                        buffer[i] = NULL;
                                        r = efi_bind_controller(
                                                        controller_handle,
                                                        *driver_image_handle,
                                                        remain_device_path);
                                        /*
                                         * For drivers that do not support the
                                         * controller or are already connected
                                         * we receive an error code here.
                                         */
                                        if (r == EFI_SUCCESS)
                                                ++connected;
                                }
                        }
                }
        }

        /*
         * TODO: Some overrides are not yet implemented:
         * - Platform Driver Override
         * - Driver Family Override Search
         * - Bus Specific Driver Override
         */

        /* Driver Binding Search */
        for (i = 0; i < count; ++i) {
                if (buffer[i]) {
                        r = efi_bind_controller(controller_handle,
                                                buffer[i],
                                                remain_device_path);
                        if (r == EFI_SUCCESS)
                                ++connected;
                }
        }

        efi_free_pool(buffer);
        if (!connected)
                return EFI_NOT_FOUND;
        return EFI_SUCCESS;
}

/*
 * Connect a controller to a driver.
 *
 * This function implements the ConnectController service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * First all driver binding protocol handles are tried for binding drivers.
 * Afterwards all handles that have openened a protocol of the controller
 * with EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER are connected to drivers.
 *
 * @controller_handle   handle of the controller
 * @driver_image_handle handle of the driver
 * @remain_device_path  device path of a child controller
 * @recursive           true to connect all child controllers
 * @return              status code
 */
static efi_status_t EFIAPI efi_connect_controller(
                        efi_handle_t controller_handle,
                        efi_handle_t *driver_image_handle,
                        struct efi_device_path *remain_device_path,
                        bool recursive)
{
        efi_status_t r;
        efi_status_t ret = EFI_NOT_FOUND;
        struct efi_object *efiobj;

        EFI_ENTRY("%p, %p, %p, %d", controller_handle, driver_image_handle,
                  remain_device_path, recursive);

        efiobj = efi_search_obj(controller_handle);
        if (!efiobj) {
                ret = EFI_INVALID_PARAMETER;
                goto out;
        }

        r = efi_connect_single_controller(controller_handle,
                                          driver_image_handle,
                                          remain_device_path);
        if (r == EFI_SUCCESS)
                ret = EFI_SUCCESS;
        if (recursive) {
                struct efi_handler *handler;
                struct efi_open_protocol_info_item *item;

                list_for_each_entry(handler, &efiobj->protocols, link) {
                        list_for_each_entry(item, &handler->open_infos, link) {
                                if (item->info.attributes &
                                    EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER) {
                                        r = EFI_CALL(efi_connect_controller(
                                                item->info.controller_handle,
                                                driver_image_handle,
                                                remain_device_path,
                                                recursive));
                                        if (r == EFI_SUCCESS)
                                                ret = EFI_SUCCESS;
                                }
                        }
                }
        }
        /*  Check for child controller specified by end node */
        if (ret != EFI_SUCCESS && remain_device_path &&
            remain_device_path->type == DEVICE_PATH_TYPE_END)
                ret = EFI_SUCCESS;
out:
        return EFI_EXIT(ret);
}

/*
 * Reinstall protocol interface.
 *
 * This function implements the ReinstallProtocolInterface service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * The old interface is uninstalled. The new interface is installed.
 * Drivers are connected.
 *
 * @handle                      handle on which the protocol shall be
 *                              reinstalled
 * @protocol                    GUID of the protocol to be installed
 * @old_interface               interface to be removed
 * @new_interface               interface to be installed
 * @return                      status code
 */
static efi_status_t EFIAPI efi_reinstall_protocol_interface(
                        efi_handle_t handle, const efi_guid_t *protocol,
                        void *old_interface, void *new_interface)
{
        efi_status_t ret;

        EFI_ENTRY("%p, %pUl, %p, %p", handle, protocol, old_interface,
                  new_interface);
        ret = EFI_CALL(efi_uninstall_protocol_interface(handle, protocol,
                                                        old_interface));
        if (ret != EFI_SUCCESS)
                goto out;
        ret = EFI_CALL(efi_install_protocol_interface(&handle, protocol,
                                                      EFI_NATIVE_INTERFACE,
                                                      new_interface));
        if (ret != EFI_SUCCESS)
                goto out;
        /*
         * The returned status code has to be ignored.
         * Do not create an error if no suitable driver for the handle exists.
         */
        EFI_CALL(efi_connect_controller(handle, NULL, NULL, true));
out:
        return EFI_EXIT(ret);
}

/*
 * Get all child controllers associated to a driver.
 * The allocated buffer has to be freed with free().
 *
 * @efiobj                      handle of the controller
 * @driver_handle               handle of the driver
 * @number_of_children          number of child controllers
 * @child_handle_buffer         handles of the the child controllers
 */
static efi_status_t efi_get_child_controllers(
                                struct efi_object *efiobj,
                                efi_handle_t driver_handle,
                                efi_uintn_t *number_of_children,
                                efi_handle_t **child_handle_buffer)
{
        struct efi_handler *handler;
        struct efi_open_protocol_info_item *item;
        efi_uintn_t count = 0, i;
        bool duplicate;

        /* Count all child controller associations */
        list_for_each_entry(handler, &efiobj->protocols, link) {
                list_for_each_entry(item, &handler->open_infos, link) {
                        if (item->info.agent_handle == driver_handle &&
                            item->info.attributes &
                            EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER)
                                ++count;
                }
        }
        /*
         * Create buffer. In case of duplicate child controller assignments
         * the buffer will be too large. But that does not harm.
         */
        *number_of_children = 0;
        *child_handle_buffer = calloc(count, sizeof(efi_handle_t));
        if (!*child_handle_buffer)
                return EFI_OUT_OF_RESOURCES;
        /* Copy unique child handles */
        list_for_each_entry(handler, &efiobj->protocols, link) {
                list_for_each_entry(item, &handler->open_infos, link) {
                        if (item->info.agent_handle == driver_handle &&
                            item->info.attributes &
                            EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER) {
                                /* Check this is a new child controller */
                                duplicate = false;
                                for (i = 0; i < *number_of_children; ++i) {
                                        if ((*child_handle_buffer)[i] ==
                                            item->info.controller_handle)
                                                duplicate = true;
                                }
                                /* Copy handle to buffer */
                                if (!duplicate) {
                                        i = (*number_of_children)++;
                                        (*child_handle_buffer)[i] =
                                                item->info.controller_handle;
                                }
                        }
                }
        }
        return EFI_SUCCESS;
}

/*
 * Disconnect a controller from a driver.
 *
 * This function implements the DisconnectController service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * @controller_handle   handle of the controller
 * @driver_image_handle handle of the driver
 * @child_handle        handle of the child to destroy
 * @return              status code
 */
static efi_status_t EFIAPI efi_disconnect_controller(
                                efi_handle_t controller_handle,
                                efi_handle_t driver_image_handle,
                                efi_handle_t child_handle)
{
        struct efi_driver_binding_protocol *binding_protocol;
        efi_handle_t *child_handle_buffer = NULL;
        size_t number_of_children = 0;
        efi_status_t r;
        size_t stop_count = 0;
        struct efi_object *efiobj;

        EFI_ENTRY("%p, %p, %p", controller_handle, driver_image_handle,
                  child_handle);

        efiobj = efi_search_obj(controller_handle);
        if (!efiobj) {
                r = EFI_INVALID_PARAMETER;
                goto out;
        }

        if (child_handle && !efi_search_obj(child_handle)) {
                r = EFI_INVALID_PARAMETER;
                goto out;
        }

        /* If no driver handle is supplied, disconnect all drivers */
        if (!driver_image_handle) {
                r = efi_disconnect_all_drivers(efiobj, NULL, child_handle);
                goto out;
        }

        /* Create list of child handles */
        if (child_handle) {
                number_of_children = 1;
                child_handle_buffer = &child_handle;
        } else {
                efi_get_child_controllers(efiobj,
                                          driver_image_handle,
                                          &number_of_children,
                                          &child_handle_buffer);
        }

        /* Get the driver binding protocol */
        r = EFI_CALL(efi_open_protocol(driver_image_handle,
                                       &efi_guid_driver_binding_protocol,
                                       (void **)&binding_protocol,
                                       driver_image_handle, NULL,
                                       EFI_OPEN_PROTOCOL_GET_PROTOCOL));
        if (r != EFI_SUCCESS)
                goto out;
        /* Remove the children */
        if (number_of_children) {
                r = EFI_CALL(binding_protocol->stop(binding_protocol,
                                                    controller_handle,
                                                    number_of_children,
                                                    child_handle_buffer));
                if (r == EFI_SUCCESS)
                        ++stop_count;
        }
        /* Remove the driver */
        if (!child_handle)
                r = EFI_CALL(binding_protocol->stop(binding_protocol,
                                                    controller_handle,
                                                    0, NULL));
        if (r == EFI_SUCCESS)
                ++stop_count;
        EFI_CALL(efi_close_protocol(driver_image_handle,
                                    &efi_guid_driver_binding_protocol,
                                    driver_image_handle, NULL));

        if (stop_count)
                r = EFI_SUCCESS;
        else
                r = EFI_NOT_FOUND;
out:
        if (!child_handle)
                free(child_handle_buffer);
        return EFI_EXIT(r);
}

static const struct efi_boot_services efi_boot_services = {
        .hdr = {
                .headersize = sizeof(struct efi_table_hdr),
        },
        .raise_tpl = efi_raise_tpl,
        .restore_tpl = efi_restore_tpl,
        .allocate_pages = efi_allocate_pages_ext,
        .free_pages = efi_free_pages_ext,
        .get_memory_map = efi_get_memory_map_ext,
        .allocate_pool = efi_allocate_pool_ext,
        .free_pool = efi_free_pool_ext,
        .create_event = efi_create_event_ext,
        .set_timer = efi_set_timer_ext,
        .wait_for_event = efi_wait_for_event,
        .signal_event = efi_signal_event_ext,
        .close_event = efi_close_event,
        .check_event = efi_check_event,
        .install_protocol_interface = efi_install_protocol_interface,
        .reinstall_protocol_interface = efi_reinstall_protocol_interface,
        .uninstall_protocol_interface = efi_uninstall_protocol_interface,
        .handle_protocol = efi_handle_protocol,
        .reserved = NULL,
        .register_protocol_notify = efi_register_protocol_notify,
        .locate_handle = efi_locate_handle_ext,
        .locate_device_path = efi_locate_device_path,
        .install_configuration_table = efi_install_configuration_table_ext,
        .load_image = efi_load_image,
        .start_image = efi_start_image,
        .exit = efi_exit,
        .unload_image = efi_unload_image,
        .exit_boot_services = efi_exit_boot_services,
        .get_next_monotonic_count = efi_get_next_monotonic_count,
        .stall = efi_stall,
        .set_watchdog_timer = efi_set_watchdog_timer,
        .connect_controller = efi_connect_controller,
        .disconnect_controller = efi_disconnect_controller,
        .open_protocol = efi_open_protocol,
        .close_protocol = efi_close_protocol,
        .open_protocol_information = efi_open_protocol_information,
        .protocols_per_handle = efi_protocols_per_handle,
        .locate_handle_buffer = efi_locate_handle_buffer,
        .locate_protocol = efi_locate_protocol,
        .install_multiple_protocol_interfaces =
                        efi_install_multiple_protocol_interfaces,
        .uninstall_multiple_protocol_interfaces =
                        efi_uninstall_multiple_protocol_interfaces,
        .calculate_crc32 = efi_calculate_crc32,
        .copy_mem = efi_copy_mem,
        .set_mem = efi_set_mem,
        .create_event_ex = efi_create_event_ex,
};

static uint16_t __efi_runtime_data firmware_vendor[] = L"Das U-Boot";

struct efi_system_table __efi_runtime_data systab = {
        .hdr = {
                .signature = EFI_SYSTEM_TABLE_SIGNATURE,
                .revision = 2 << 16 | 70, /* 2.7 */
                .headersize = sizeof(struct efi_table_hdr),
        },
        .fw_vendor = (long)firmware_vendor,
        .con_in = (void *)&efi_con_in,
        .con_out = (void *)&efi_con_out,
        .std_err = (void *)&efi_con_out,
        .runtime = (void *)&efi_runtime_services,
        .boottime = (void *)&efi_boot_services,
        .nr_tables = 0,
        .tables = (void *)efi_conf_table,
};