Quelle  runtime-wrappers.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * runtime-wrappers.c - Runtime Services function call wrappers
 *
 * Implementation summary:
 * -----------------------
 * 1. When user/kernel thread requests to execute efi_runtime_service(),
 * enqueue work to efi_rts_wq.
 * 2. Caller thread waits for completion until the work is finished
 * because it's dependent on the return status and execution of
 * efi_runtime_service().
 * For instance, get_variable() and get_next_variable().
 *
 * Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.org>
 *
 * Split off from arch/x86/platform/efi/efi.c
 *
 * Copyright (C) 1999 VA Linux Systems
 * Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
 * Copyright (C) 1999-2002 Hewlett-Packard Co.
 * Copyright (C) 2005-2008 Intel Co.
 * Copyright (C) 2013 SuSE Labs
 */

#define pr_fmt(fmt) "efi: " fmt

#include <linux/bug.h>
#include <linux/efi.h>
#include <linux/irqflags.h>
#include <linux/mutex.h>
#include <linux/semaphore.h>
#include <linux/stringify.h>
#include <linux/workqueue.h>
#include <linux/completion.h>

#include <asm/efi.h>

/*
 * Wrap around the new efi_call_virt_generic() macros so that the
 * code doesn't get too cluttered:
 */
#define efi_call_virt(f, args...)   \
 arch_efi_call_virt(efi.runtime, f, args)

union efi_rts_args {
 struct {
  efi_time_t  *time;
  efi_time_cap_t *capabilities;
 } GET_TIME;

 struct {
  efi_time_t *time;
 } SET_TIME;

 struct {
  efi_bool_t *enabled;
  efi_bool_t *pending;
  efi_time_t *time;
 } GET_WAKEUP_TIME;

 struct {
  efi_bool_t enable;
  efi_time_t *time;
 } SET_WAKEUP_TIME;

 struct {
  efi_char16_t *name;
  efi_guid_t *vendor;
  u32  *attr;
  unsigned long *data_size;
  void  *data;
 } GET_VARIABLE;

 struct {
  unsigned long *name_size;
  efi_char16_t *name;
  efi_guid_t  *vendor;
 } GET_NEXT_VARIABLE;

 struct {
  efi_char16_t *name;
  efi_guid_t *vendor;
  u32  attr;
  unsigned long data_size;
  void  *data;
 } SET_VARIABLE;

 struct {
  u32  attr;
  u64  *storage_space;
  u64  *remaining_space;
  u64  *max_variable_size;
 } QUERY_VARIABLE_INFO;

 struct {
  u32  *high_count;
 } GET_NEXT_HIGH_MONO_COUNT;

 struct {
  efi_capsule_header_t **capsules;
  unsigned long count;
  unsigned long sg_list;
 } UPDATE_CAPSULE;

 struct {
  efi_capsule_header_t **capsules;
  unsigned long count;
  u64  *max_size;
  int  *reset_type;
 } QUERY_CAPSULE_CAPS;

 struct {
  efi_status_t (__efiapi *acpi_prm_handler)(u64, void *);
  u64  param_buffer_addr;
  void  *context;
 } ACPI_PRM_HANDLER;
};

struct efi_runtime_work efi_rts_work;

/*
 * efi_queue_work: Queue EFI runtime service call and wait for completion
 * @_rts: EFI runtime service function identifier
 * @_args: Arguments to pass to the EFI runtime service
 *
 * Accesses to efi_runtime_services() are serialized by a binary
 * semaphore (efi_runtime_lock) and caller waits until the work is
 * finished, hence _only_ one work is queued at a time and the caller
 * thread waits for completion.
 */
#define efi_queue_work(_rts, _args...)     \
 __efi_queue_work(EFI_ ## _rts,     \
    &(union efi_rts_args){ ._rts = { _args }})

#ifndef arch_efi_save_flags
#define arch_efi_save_flags(state_flags) local_save_flags(state_flags)
#define arch_efi_restore_flags(state_flags) local_irq_restore(state_flags)
#endif

unsigned long efi_call_virt_save_flags(void)
{
 unsigned long flags;

 arch_efi_save_flags(flags);
 return flags;
}

void efi_call_virt_check_flags(unsigned long flags, const void *caller)
{
 unsigned long cur_flags, mismatch;

 cur_flags = efi_call_virt_save_flags();

 mismatch = flags ^ cur_flags;
 if (!WARN_ON_ONCE(mismatch & ARCH_EFI_IRQ_FLAGS_MASK))
  return;

 add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_NOW_UNRELIABLE);
 pr_err_ratelimited(FW_BUG "IRQ flags corrupted (0x%08lx=>0x%08lx) by EFI call from %pS\n",
      flags, cur_flags, caller ?: __builtin_return_address(0));
 arch_efi_restore_flags(flags);
}

/*
 * According to section 7.1 of the UEFI spec, Runtime Services are not fully
 * reentrant, and there are particular combinations of calls that need to be
 * serialized. (source: UEFI Specification v2.4A)
 *
 * Table 31. Rules for Reentry Into Runtime Services
 * +------------------------------------+-------------------------------+
 * | If previous call is busy in | Forbidden to call |
 * +------------------------------------+-------------------------------+
 * | Any | SetVirtualAddressMap() |
 * +------------------------------------+-------------------------------+
 * | ConvertPointer() | ConvertPointer() |
 * +------------------------------------+-------------------------------+
 * | SetVariable() | ResetSystem() |
 * | UpdateCapsule() | |
 * | SetTime() | |
 * | SetWakeupTime() | |
 * | GetNextHighMonotonicCount() | |
 * +------------------------------------+-------------------------------+
 * | GetVariable() | GetVariable() |
 * | GetNextVariableName() | GetNextVariableName() |
 * | SetVariable() | SetVariable() |
 * | QueryVariableInfo() | QueryVariableInfo() |
 * | UpdateCapsule() | UpdateCapsule() |
 * | QueryCapsuleCapabilities() | QueryCapsuleCapabilities() |
 * | GetNextHighMonotonicCount() | GetNextHighMonotonicCount() |
 * +------------------------------------+-------------------------------+
 * | GetTime() | GetTime() |
 * | SetTime() | SetTime() |
 * | GetWakeupTime() | GetWakeupTime() |
 * | SetWakeupTime() | SetWakeupTime() |
 * +------------------------------------+-------------------------------+
 *
 * Due to the fact that the EFI pstore may write to the variable store in
 * interrupt context, we need to use a lock for at least the groups that
 * contain SetVariable() and QueryVariableInfo(). That leaves little else, as
 * none of the remaining functions are actually ever called at runtime.
 * So let's just use a single lock to serialize all Runtime Services calls.
 */
static DEFINE_SEMAPHORE(efi_runtime_lock, 1);

/*
 * Expose the EFI runtime lock to the UV platform
 */
#ifdef CONFIG_X86_UV
extern struct semaphore __efi_uv_runtime_lock __alias(efi_runtime_lock);
#endif

/*
 * Calls the appropriate efi_runtime_service() with the appropriate
 * arguments.
 */
static void __nocfi efi_call_rts(struct work_struct *work)
{
 const union efi_rts_args *args = efi_rts_work.args;
 efi_status_t status = EFI_NOT_FOUND;
 unsigned long flags;

 arch_efi_call_virt_setup();
 flags = efi_call_virt_save_flags();

 switch (efi_rts_work.efi_rts_id) {
 case EFI_GET_TIME:
  status = efi_call_virt(get_time,
           args->GET_TIME.time,
           args->GET_TIME.capabilities);
  break;
 case EFI_SET_TIME:
  status = efi_call_virt(set_time,
           args->SET_TIME.time);
  break;
 case EFI_GET_WAKEUP_TIME:
  status = efi_call_virt(get_wakeup_time,
           args->GET_WAKEUP_TIME.enabled,
           args->GET_WAKEUP_TIME.pending,
           args->GET_WAKEUP_TIME.time);
  break;
 case EFI_SET_WAKEUP_TIME:
  status = efi_call_virt(set_wakeup_time,
           args->SET_WAKEUP_TIME.enable,
           args->SET_WAKEUP_TIME.time);
  break;
 case EFI_GET_VARIABLE:
  status = efi_call_virt(get_variable,
           args->GET_VARIABLE.name,
           args->GET_VARIABLE.vendor,
           args->GET_VARIABLE.attr,
           args->GET_VARIABLE.data_size,
           args->GET_VARIABLE.data);
  break;
 case EFI_GET_NEXT_VARIABLE:
  status = efi_call_virt(get_next_variable,
           args->GET_NEXT_VARIABLE.name_size,
           args->GET_NEXT_VARIABLE.name,
           args->GET_NEXT_VARIABLE.vendor);
  break;
 case EFI_SET_VARIABLE:
  status = efi_call_virt(set_variable,
           args->SET_VARIABLE.name,
           args->SET_VARIABLE.vendor,
           args->SET_VARIABLE.attr,
           args->SET_VARIABLE.data_size,
           args->SET_VARIABLE.data);
  break;
 case EFI_QUERY_VARIABLE_INFO:
  status = efi_call_virt(query_variable_info,
           args->QUERY_VARIABLE_INFO.attr,
           args->QUERY_VARIABLE_INFO.storage_space,
           args->QUERY_VARIABLE_INFO.remaining_space,
           args->QUERY_VARIABLE_INFO.max_variable_size);
  break;
 case EFI_GET_NEXT_HIGH_MONO_COUNT:
  status = efi_call_virt(get_next_high_mono_count,
           args->GET_NEXT_HIGH_MONO_COUNT.high_count);
  break;
 case EFI_UPDATE_CAPSULE:
  status = efi_call_virt(update_capsule,
           args->UPDATE_CAPSULE.capsules,
           args->UPDATE_CAPSULE.count,
           args->UPDATE_CAPSULE.sg_list);
  break;
 case EFI_QUERY_CAPSULE_CAPS:
  status = efi_call_virt(query_capsule_caps,
           args->QUERY_CAPSULE_CAPS.capsules,
           args->QUERY_CAPSULE_CAPS.count,
           args->QUERY_CAPSULE_CAPS.max_size,
           args->QUERY_CAPSULE_CAPS.reset_type);
  break;
 case EFI_ACPI_PRM_HANDLER:
#ifdef CONFIG_ACPI_PRMT
  status = arch_efi_call_virt(args, ACPI_PRM_HANDLER.acpi_prm_handler,
         args->ACPI_PRM_HANDLER.param_buffer_addr,
         args->ACPI_PRM_HANDLER.context);
  break;
#endif
 default:
  /*
 * Ideally, we should never reach here because a caller of this
 * function should have put the right efi_runtime_service()
 * function identifier into efi_rts_work->efi_rts_id
 */
  pr_err("Requested executing invalid EFI Runtime Service.\n");
 }

 efi_call_virt_check_flags(flags, efi_rts_work.caller);
 arch_efi_call_virt_teardown();

 efi_rts_work.status = status;
 complete(&efi_rts_work.efi_rts_comp);
}

static efi_status_t __efi_queue_work(enum efi_rts_ids id,
         union efi_rts_args *args)
{
 efi_rts_work.efi_rts_id = id;
 efi_rts_work.args = args;
 efi_rts_work.caller = __builtin_return_address(0);
 efi_rts_work.status = EFI_ABORTED;

 if (!efi_enabled(EFI_RUNTIME_SERVICES)) {
  pr_warn_once("EFI Runtime Services are disabled!\n");
  efi_rts_work.status = EFI_DEVICE_ERROR;
  goto exit;
 }

 init_completion(&efi_rts_work.efi_rts_comp);
 INIT_WORK(&efi_rts_work.work, efi_call_rts);

 /*
 * queue_work() returns 0 if work was already on queue,
 * _ideally_ this should never happen.
 */
 if (queue_work(efi_rts_wq, &efi_rts_work.work))
  wait_for_completion(&efi_rts_work.efi_rts_comp);
 else
  pr_err("Failed to queue work to efi_rts_wq.\n");

 WARN_ON_ONCE(efi_rts_work.status == EFI_ABORTED);
exit:
 efi_rts_work.efi_rts_id = EFI_NONE;
 return efi_rts_work.status;
}

static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc)
{
 efi_status_t status;

 if (down_interruptible(&efi_runtime_lock))
  return EFI_ABORTED;
 status = efi_queue_work(GET_TIME, tm, tc);
 up(&efi_runtime_lock);
 return status;
}

static efi_status_t virt_efi_set_time(efi_time_t *tm)
{
 efi_status_t status;

 if (down_interruptible(&efi_runtime_lock))
  return EFI_ABORTED;
 status = efi_queue_work(SET_TIME, tm);
 up(&efi_runtime_lock);
 return status;
}

static efi_status_t virt_efi_get_wakeup_time(efi_bool_t *enabled,
          efi_bool_t *pending,
          efi_time_t *tm)
{
 efi_status_t status;

 if (down_interruptible(&efi_runtime_lock))
  return EFI_ABORTED;
 status = efi_queue_work(GET_WAKEUP_TIME, enabled, pending, tm);
 up(&efi_runtime_lock);
 return status;
}

static efi_status_t virt_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
{
 efi_status_t status;

 if (down_interruptible(&efi_runtime_lock))
  return EFI_ABORTED;
 status = efi_queue_work(SET_WAKEUP_TIME, enabled, tm);
 up(&efi_runtime_lock);
 return status;
}

static efi_status_t virt_efi_get_variable(efi_char16_t *name,
       efi_guid_t *vendor,
       u32 *attr,
       unsigned long *data_size,
       void *data)
{
 efi_status_t status;

 if (down_interruptible(&efi_runtime_lock))
  return EFI_ABORTED;
 status = efi_queue_work(GET_VARIABLE, name, vendor, attr, data_size,
    data);
 up(&efi_runtime_lock);
 return status;
}

static efi_status_t virt_efi_get_next_variable(unsigned long *name_size,
            efi_char16_t *name,
            efi_guid_t *vendor)
{
 efi_status_t status;

 if (down_interruptible(&efi_runtime_lock))
  return EFI_ABORTED;
 status = efi_queue_work(GET_NEXT_VARIABLE, name_size, name, vendor);
 up(&efi_runtime_lock);
 return status;
}

static efi_status_t virt_efi_set_variable(efi_char16_t *name,
       efi_guid_t *vendor,
       u32 attr,
       unsigned long data_size,
       void *data)
{
 efi_status_t status;

 if (down_interruptible(&efi_runtime_lock))
  return EFI_ABORTED;
 status = efi_queue_work(SET_VARIABLE, name, vendor, attr, data_size,
    data);
 up(&efi_runtime_lock);
 return status;
}

static efi_status_t __nocfi
virt_efi_set_variable_nb(efi_char16_t *name, efi_guid_t *vendor, u32 attr,
    unsigned long data_size, void *data)
{
 efi_status_t status;

 if (down_trylock(&efi_runtime_lock))
  return EFI_NOT_READY;

 status = efi_call_virt_pointer(efi.runtime, set_variable, name, vendor,
           attr, data_size, data);
 up(&efi_runtime_lock);
 return status;
}


static efi_status_t virt_efi_query_variable_info(u32 attr,
       u64 *storage_space,
       u64 *remaining_space,
       u64 *max_variable_size)
{
 efi_status_t status;

 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
  return EFI_UNSUPPORTED;

 if (down_interruptible(&efi_runtime_lock))
  return EFI_ABORTED;
 status = efi_queue_work(QUERY_VARIABLE_INFO, attr, storage_space,
    remaining_space, max_variable_size);
 up(&efi_runtime_lock);
 return status;
}

static efi_status_t __nocfi
virt_efi_query_variable_info_nb(u32 attr, u64 *storage_space,
    u64 *remaining_space, u64 *max_variable_size)
{
 efi_status_t status;

 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
  return EFI_UNSUPPORTED;

 if (down_trylock(&efi_runtime_lock))
  return EFI_NOT_READY;

 status = efi_call_virt_pointer(efi.runtime, query_variable_info, attr,
           storage_space, remaining_space,
           max_variable_size);
 up(&efi_runtime_lock);
 return status;
}

static efi_status_t virt_efi_get_next_high_mono_count(u32 *count)
{
 efi_status_t status;

 if (down_interruptible(&efi_runtime_lock))
  return EFI_ABORTED;
 status = efi_queue_work(GET_NEXT_HIGH_MONO_COUNT, count);
 up(&efi_runtime_lock);
 return status;
}

static void __nocfi
virt_efi_reset_system(int reset_type, efi_status_t status,
        unsigned long data_size, efi_char16_t *data)
{
 if (down_trylock(&efi_runtime_lock)) {
  pr_warn("failed to invoke the reset_system() runtime service:\n"
   "could not get exclusive access to the firmware\n");
  return;
 }

 arch_efi_call_virt_setup();
 efi_rts_work.efi_rts_id = EFI_RESET_SYSTEM;
 arch_efi_call_virt(efi.runtime, reset_system, reset_type, status,
      data_size, data);
 arch_efi_call_virt_teardown();

 up(&efi_runtime_lock);
}

static efi_status_t virt_efi_update_capsule(efi_capsule_header_t **capsules,
         unsigned long count,
         unsigned long sg_list)
{
 efi_status_t status;

 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
  return EFI_UNSUPPORTED;

 if (down_interruptible(&efi_runtime_lock))
  return EFI_ABORTED;
 status = efi_queue_work(UPDATE_CAPSULE, capsules, count, sg_list);
 up(&efi_runtime_lock);
 return status;
}

static efi_status_t virt_efi_query_capsule_caps(efi_capsule_header_t **capsules,
      unsigned long count,
      u64 *max_size,
      int *reset_type)
{
 efi_status_t status;

 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
  return EFI_UNSUPPORTED;

 if (down_interruptible(&efi_runtime_lock))
  return EFI_ABORTED;
 status = efi_queue_work(QUERY_CAPSULE_CAPS, capsules, count,
    max_size, reset_type);
 up(&efi_runtime_lock);
 return status;
}

void __init efi_native_runtime_setup(void)
{
 efi.get_time       = virt_efi_get_time;
 efi.set_time       = virt_efi_set_time;
 efi.get_wakeup_time      = virt_efi_get_wakeup_time;
 efi.set_wakeup_time      = virt_efi_set_wakeup_time;
 efi.get_variable      = virt_efi_get_variable;
 efi.get_next_variable      = virt_efi_get_next_variable;
 efi.set_variable      = virt_efi_set_variable;
 efi.set_variable_nonblocking     = virt_efi_set_variable_nb;
 efi.get_next_high_mono_count     = virt_efi_get_next_high_mono_count;
 efi.reset_system       = virt_efi_reset_system;
 efi.query_variable_info      = virt_efi_query_variable_info;
 efi.query_variable_info_nonblocking = virt_efi_query_variable_info_nb;
 efi.update_capsule      = virt_efi_update_capsule;
 efi.query_capsule_caps      = virt_efi_query_capsule_caps;
}

#ifdef CONFIG_ACPI_PRMT

efi_status_t
efi_call_acpi_prm_handler(efi_status_t (__efiapi *handler_addr)(u64, void *),
     u64 param_buffer_addr, void *context)
{
 efi_status_t status;

 if (down_interruptible(&efi_runtime_lock))
  return EFI_ABORTED;
 status = efi_queue_work(ACPI_PRM_HANDLER, handler_addr,
    param_buffer_addr, context);
 up(&efi_runtime_lock);
 return status;
}

#endif