drivers/firmware/efi/runtime-wrappers.c

   1 /*
   2  * runtime-wrappers.c - Runtime Services function call wrappers
   3  *
   4  * Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.org>
   5  *
   6  * Split off from arch/x86/platform/efi/efi.c
   7  *
   8  * Copyright (C) 1999 VA Linux Systems
   9  * Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
  10  * Copyright (C) 1999-2002 Hewlett-Packard Co.
  11  * Copyright (C) 2005-2008 Intel Co.
  12  * Copyright (C) 2013 SuSE Labs
  13  *
  14  * This file is released under the GPLv2.
  15  */
  16
  17 #include <linux/bug.h>
  18 #include <linux/efi.h>
  19 #include <linux/mutex.h>
  20 #include <linux/spinlock.h>
  21 #include <asm/efi.h>
  22
  23 /*
  24  * According to section 7.1 of the UEFI spec, Runtime Services are not fully
  25  * reentrant, and there are particular combinations of calls that need to be
  26  * serialized. (source: UEFI Specification v2.4A)
  27  *
  28  * Table 31. Rules for Reentry Into Runtime Services
  29  * +------------------------------------+-------------------------------+
  30  * | If previous call is busy in        | Forbidden to call             |
  31  * +------------------------------------+-------------------------------+
  32  * | Any                                | SetVirtualAddressMap()        |
  33  * +------------------------------------+-------------------------------+
  34  * | ConvertPointer()                   | ConvertPointer()              |
  35  * +------------------------------------+-------------------------------+
  36  * | SetVariable()                      | ResetSystem()                 |
  37  * | UpdateCapsule()                    |                               |
  38  * | SetTime()                          |                               |
  39  * | SetWakeupTime()                    |                               |
  40  * | GetNextHighMonotonicCount()        |                               |
  41  * +------------------------------------+-------------------------------+
  42  * | GetVariable()                      | GetVariable()                 |
  43  * | GetNextVariableName()              | GetNextVariableName()         |
  44  * | SetVariable()                      | SetVariable()                 |
  45  * | QueryVariableInfo()                | QueryVariableInfo()           |
  46  * | UpdateCapsule()                    | UpdateCapsule()               |
  47  * | QueryCapsuleCapabilities()         | QueryCapsuleCapabilities()    |
  48  * | GetNextHighMonotonicCount()        | GetNextHighMonotonicCount()   |
  49  * +------------------------------------+-------------------------------+
  50  * | GetTime()                          | GetTime()                     |
  51  * | SetTime()                          | SetTime()                     |
  52  * | GetWakeupTime()                    | GetWakeupTime()               |
  53  * | SetWakeupTime()                    | SetWakeupTime()               |
  54  * +------------------------------------+-------------------------------+
  55  *
  56  * Due to the fact that the EFI pstore may write to the variable store in
  57  * interrupt context, we need to use a spinlock for at least the groups that
  58  * contain SetVariable() and QueryVariableInfo(). That leaves little else, as
  59  * none of the remaining functions are actually ever called at runtime.
  60  * So let's just use a single spinlock to serialize all Runtime Services calls.
  61  */
  62 static DEFINE_SPINLOCK(efi_runtime_lock);
  63
  64 static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc)
  65 {
  66         unsigned long flags;
  67         efi_status_t status;
  68
  69         spin_lock_irqsave(&efi_runtime_lock, flags);
  70         status = efi_call_virt(get_time, tm, tc);
  71         spin_unlock_irqrestore(&efi_runtime_lock, flags);
  72         return status;
  73 }
  74
  75 static efi_status_t virt_efi_set_time(efi_time_t *tm)
  76 {
  77         unsigned long flags;
  78         efi_status_t status;
  79
  80         spin_lock_irqsave(&efi_runtime_lock, flags);
  81         status = efi_call_virt(set_time, tm);
  82         spin_unlock_irqrestore(&efi_runtime_lock, flags);
  83         return status;
  84 }
  85
  86 static efi_status_t virt_efi_get_wakeup_time(efi_bool_t *enabled,
  87                                              efi_bool_t *pending,
  88                                              efi_time_t *tm)
  89 {
  90         unsigned long flags;
  91         efi_status_t status;
  92
  93         spin_lock_irqsave(&efi_runtime_lock, flags);
  94         status = efi_call_virt(get_wakeup_time, enabled, pending, tm);
  95         spin_unlock_irqrestore(&efi_runtime_lock, flags);
  96         return status;
  97 }
  98
  99 static efi_status_t virt_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
 100 {
 101         unsigned long flags;
 102         efi_status_t status;
 103
 104         spin_lock_irqsave(&efi_runtime_lock, flags);
 105         status = efi_call_virt(set_wakeup_time, enabled, tm);
 106         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 107         return status;
 108 }
 109
 110 static efi_status_t virt_efi_get_variable(efi_char16_t *name,
 111                                           efi_guid_t *vendor,
 112                                           u32 *attr,
 113                                           unsigned long *data_size,
 114                                           void *data)
 115 {
 116         unsigned long flags;
 117         efi_status_t status;
 118
 119         spin_lock_irqsave(&efi_runtime_lock, flags);
 120         status = efi_call_virt(get_variable, name, vendor, attr, data_size,
 121                                data);
 122         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 123         return status;
 124 }
 125
 126 static efi_status_t virt_efi_get_next_variable(unsigned long *name_size,
 127                                                efi_char16_t *name,
 128                                                efi_guid_t *vendor)
 129 {
 130         unsigned long flags;
 131         efi_status_t status;
 132
 133         spin_lock_irqsave(&efi_runtime_lock, flags);
 134         status = efi_call_virt(get_next_variable, name_size, name, vendor);
 135         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 136         return status;
 137 }
 138
 139 static efi_status_t virt_efi_set_variable(efi_char16_t *name,
 140                                           efi_guid_t *vendor,
 141                                           u32 attr,
 142                                           unsigned long data_size,
 143                                           void *data)
 144 {
 145         unsigned long flags;
 146         efi_status_t status;
 147
 148         spin_lock_irqsave(&efi_runtime_lock, flags);
 149         status = efi_call_virt(set_variable, name, vendor, attr, data_size,
 150                                data);
 151         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 152         return status;
 153 }
 154
 155 static efi_status_t
 156 virt_efi_set_variable_nonblocking(efi_char16_t *name, efi_guid_t *vendor,
 157                                   u32 attr, unsigned long data_size,
 158                                   void *data)
 159 {
 160         unsigned long flags;
 161         efi_status_t status;
 162
 163         if (!spin_trylock_irqsave(&efi_runtime_lock, flags))
 164                 return EFI_NOT_READY;
 165
 166         status = efi_call_virt(set_variable, name, vendor, attr, data_size,
 167                                data);
 168         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 169         return status;
 170 }
 171
 172
 173 static efi_status_t virt_efi_query_variable_info(u32 attr,
 174                                                  u64 *storage_space,
 175                                                  u64 *remaining_space,
 176                                                  u64 *max_variable_size)
 177 {
 178         unsigned long flags;
 179         efi_status_t status;
 180
 181         if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
 182                 return EFI_UNSUPPORTED;
 183
 184         spin_lock_irqsave(&efi_runtime_lock, flags);
 185         status = efi_call_virt(query_variable_info, attr, storage_space,
 186                                remaining_space, max_variable_size);
 187         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 188         return status;
 189 }
 190
 191 static efi_status_t
 192 virt_efi_query_variable_info_nonblocking(u32 attr,
 193                                          u64 *storage_space,
 194                                          u64 *remaining_space,
 195                                          u64 *max_variable_size)
 196 {
 197         unsigned long flags;
 198         efi_status_t status;
 199
 200         if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
 201                 return EFI_UNSUPPORTED;
 202
 203         if (!spin_trylock_irqsave(&efi_runtime_lock, flags))
 204                 return EFI_NOT_READY;
 205
 206         status = efi_call_virt(query_variable_info, attr, storage_space,
 207                                remaining_space, max_variable_size);
 208         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 209         return status;
 210 }
 211
 212 static efi_status_t virt_efi_get_next_high_mono_count(u32 *count)
 213 {
 214         unsigned long flags;
 215         efi_status_t status;
 216
 217         spin_lock_irqsave(&efi_runtime_lock, flags);
 218         status = efi_call_virt(get_next_high_mono_count, count);
 219         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 220         return status;
 221 }
 222
 223 static void virt_efi_reset_system(int reset_type,
 224                                   efi_status_t status,
 225                                   unsigned long data_size,
 226                                   efi_char16_t *data)
 227 {
 228         unsigned long flags;
 229
 230         spin_lock_irqsave(&efi_runtime_lock, flags);
 231         __efi_call_virt(reset_system, reset_type, status, data_size, data);
 232         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 233 }
 234
 235 static efi_status_t virt_efi_update_capsule(efi_capsule_header_t **capsules,
 236                                             unsigned long count,
 237                                             unsigned long sg_list)
 238 {
 239         unsigned long flags;
 240         efi_status_t status;
 241
 242         if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
 243                 return EFI_UNSUPPORTED;
 244
 245         spin_lock_irqsave(&efi_runtime_lock, flags);
 246         status = efi_call_virt(update_capsule, capsules, count, sg_list);
 247         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 248         return status;
 249 }
 250
 251 static efi_status_t virt_efi_query_capsule_caps(efi_capsule_header_t **capsules,
 252                                                 unsigned long count,
 253                                                 u64 *max_size,
 254                                                 int *reset_type)
 255 {
 256         unsigned long flags;
 257         efi_status_t status;
 258
 259         if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
 260                 return EFI_UNSUPPORTED;
 261
 262         spin_lock_irqsave(&efi_runtime_lock, flags);
 263         status = efi_call_virt(query_capsule_caps, capsules, count, max_size,
 264                                reset_type);
 265         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 266         return status;
 267 }
 268
 269 void efi_native_runtime_setup(void)
 270 {
 271         efi.get_time = virt_efi_get_time;
 272         efi.set_time = virt_efi_set_time;
 273         efi.get_wakeup_time = virt_efi_get_wakeup_time;
 274         efi.set_wakeup_time = virt_efi_set_wakeup_time;
 275         efi.get_variable = virt_efi_get_variable;
 276         efi.get_next_variable = virt_efi_get_next_variable;
 277         efi.set_variable = virt_efi_set_variable;
 278         efi.set_variable_nonblocking = virt_efi_set_variable_nonblocking;
 279         efi.get_next_high_mono_count = virt_efi_get_next_high_mono_count;
 280         efi.reset_system = virt_efi_reset_system;
 281         efi.query_variable_info = virt_efi_query_variable_info;
 282         efi.query_variable_info_nonblocking = virt_efi_query_variable_info_nonblocking;
 283         efi.update_capsule = virt_efi_update_capsule;
 284         efi.query_capsule_caps = virt_efi_query_capsule_caps;
 285 }