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/irqflags.h>
  20 #include <linux/mutex.h>
  21 #include <linux/spinlock.h>
  22 #include <linux/stringify.h>
  23 #include <asm/efi.h>
  24
  25 /*
  26  * Wrap around the new efi_call_virt_generic() macros so that the
  27  * code doesn't get too cluttered:
  28  */
  29 #define efi_call_virt(f, args...)   \
  30         efi_call_virt_pointer(efi.systab->runtime, f, args)
  31 #define __efi_call_virt(f, args...) \
  32         __efi_call_virt_pointer(efi.systab->runtime, f, args)
  33
  34 void efi_call_virt_check_flags(unsigned long flags, const char *call)
  35 {
  36         unsigned long cur_flags, mismatch;
  37
  38         local_save_flags(cur_flags);
  39
  40         mismatch = flags ^ cur_flags;
  41         if (!WARN_ON_ONCE(mismatch & ARCH_EFI_IRQ_FLAGS_MASK))
  42                 return;
  43
  44         add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_NOW_UNRELIABLE);
  45         pr_err_ratelimited(FW_BUG "IRQ flags corrupted (0x%08lx=>0x%08lx) by EFI %s\n",
  46                            flags, cur_flags, call);
  47         local_irq_restore(flags);
  48 }
  49
  50 /*
  51  * According to section 7.1 of the UEFI spec, Runtime Services are not fully
  52  * reentrant, and there are particular combinations of calls that need to be
  53  * serialized. (source: UEFI Specification v2.4A)
  54  *
  55  * Table 31. Rules for Reentry Into Runtime Services
  56  * +------------------------------------+-------------------------------+
  57  * | If previous call is busy in        | Forbidden to call             |
  58  * +------------------------------------+-------------------------------+
  59  * | Any                                | SetVirtualAddressMap()        |
  60  * +------------------------------------+-------------------------------+
  61  * | ConvertPointer()                   | ConvertPointer()              |
  62  * +------------------------------------+-------------------------------+
  63  * | SetVariable()                      | ResetSystem()                 |
  64  * | UpdateCapsule()                    |                               |
  65  * | SetTime()                          |                               |
  66  * | SetWakeupTime()                    |                               |
  67  * | GetNextHighMonotonicCount()        |                               |
  68  * +------------------------------------+-------------------------------+
  69  * | GetVariable()                      | GetVariable()                 |
  70  * | GetNextVariableName()              | GetNextVariableName()         |
  71  * | SetVariable()                      | SetVariable()                 |
  72  * | QueryVariableInfo()                | QueryVariableInfo()           |
  73  * | UpdateCapsule()                    | UpdateCapsule()               |
  74  * | QueryCapsuleCapabilities()         | QueryCapsuleCapabilities()    |
  75  * | GetNextHighMonotonicCount()        | GetNextHighMonotonicCount()   |
  76  * +------------------------------------+-------------------------------+
  77  * | GetTime()                          | GetTime()                     |
  78  * | SetTime()                          | SetTime()                     |
  79  * | GetWakeupTime()                    | GetWakeupTime()               |
  80  * | SetWakeupTime()                    | SetWakeupTime()               |
  81  * +------------------------------------+-------------------------------+
  82  *
  83  * Due to the fact that the EFI pstore may write to the variable store in
  84  * interrupt context, we need to use a spinlock for at least the groups that
  85  * contain SetVariable() and QueryVariableInfo(). That leaves little else, as
  86  * none of the remaining functions are actually ever called at runtime.
  87  * So let's just use a single spinlock to serialize all Runtime Services calls.
  88  */
  89 static DEFINE_SPINLOCK(efi_runtime_lock);
  90
  91 static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc)
  92 {
  93         efi_status_t status;
  94
  95         spin_lock(&efi_runtime_lock);
  96         status = efi_call_virt(get_time, tm, tc);
  97         spin_unlock(&efi_runtime_lock);
  98         return status;
  99 }
 100
 101 static efi_status_t virt_efi_set_time(efi_time_t *tm)
 102 {
 103         efi_status_t status;
 104
 105         spin_lock(&efi_runtime_lock);
 106         status = efi_call_virt(set_time, tm);
 107         spin_unlock(&efi_runtime_lock);
 108         return status;
 109 }
 110
 111 static efi_status_t virt_efi_get_wakeup_time(efi_bool_t *enabled,
 112                                              efi_bool_t *pending,
 113                                              efi_time_t *tm)
 114 {
 115         efi_status_t status;
 116
 117         spin_lock(&efi_runtime_lock);
 118         status = efi_call_virt(get_wakeup_time, enabled, pending, tm);
 119         spin_unlock(&efi_runtime_lock);
 120         return status;
 121 }
 122
 123 static efi_status_t virt_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
 124 {
 125         efi_status_t status;
 126
 127         spin_lock(&efi_runtime_lock);
 128         status = efi_call_virt(set_wakeup_time, enabled, tm);
 129         spin_unlock(&efi_runtime_lock);
 130         return status;
 131 }
 132
 133 static efi_status_t virt_efi_get_variable(efi_char16_t *name,
 134                                           efi_guid_t *vendor,
 135                                           u32 *attr,
 136                                           unsigned long *data_size,
 137                                           void *data)
 138 {
 139         efi_status_t status;
 140
 141         spin_lock(&efi_runtime_lock);
 142         status = efi_call_virt(get_variable, name, vendor, attr, data_size,
 143                                data);
 144         spin_unlock(&efi_runtime_lock);
 145         return status;
 146 }
 147
 148 static efi_status_t virt_efi_get_next_variable(unsigned long *name_size,
 149                                                efi_char16_t *name,
 150                                                efi_guid_t *vendor)
 151 {
 152         efi_status_t status;
 153
 154         spin_lock(&efi_runtime_lock);
 155         status = efi_call_virt(get_next_variable, name_size, name, vendor);
 156         spin_unlock(&efi_runtime_lock);
 157         return status;
 158 }
 159
 160 static efi_status_t virt_efi_set_variable(efi_char16_t *name,
 161                                           efi_guid_t *vendor,
 162                                           u32 attr,
 163                                           unsigned long data_size,
 164                                           void *data)
 165 {
 166         efi_status_t status;
 167
 168         spin_lock(&efi_runtime_lock);
 169         status = efi_call_virt(set_variable, name, vendor, attr, data_size,
 170                                data);
 171         spin_unlock(&efi_runtime_lock);
 172         return status;
 173 }
 174
 175 static efi_status_t
 176 virt_efi_set_variable_nonblocking(efi_char16_t *name, efi_guid_t *vendor,
 177                                   u32 attr, unsigned long data_size,
 178                                   void *data)
 179 {
 180         efi_status_t status;
 181
 182         if (!spin_trylock(&efi_runtime_lock))
 183                 return EFI_NOT_READY;
 184
 185         status = efi_call_virt(set_variable, name, vendor, attr, data_size,
 186                                data);
 187         spin_unlock(&efi_runtime_lock);
 188         return status;
 189 }
 190
 191
 192 static efi_status_t virt_efi_query_variable_info(u32 attr,
 193                                                  u64 *storage_space,
 194                                                  u64 *remaining_space,
 195                                                  u64 *max_variable_size)
 196 {
 197         efi_status_t status;
 198
 199         if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
 200                 return EFI_UNSUPPORTED;
 201
 202         spin_lock(&efi_runtime_lock);
 203         status = efi_call_virt(query_variable_info, attr, storage_space,
 204                                remaining_space, max_variable_size);
 205         spin_unlock(&efi_runtime_lock);
 206         return status;
 207 }
 208
 209 static efi_status_t
 210 virt_efi_query_variable_info_nonblocking(u32 attr,
 211                                          u64 *storage_space,
 212                                          u64 *remaining_space,
 213                                          u64 *max_variable_size)
 214 {
 215         efi_status_t status;
 216
 217         if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
 218                 return EFI_UNSUPPORTED;
 219
 220         if (!spin_trylock(&efi_runtime_lock))
 221                 return EFI_NOT_READY;
 222
 223         status = efi_call_virt(query_variable_info, attr, storage_space,
 224                                remaining_space, max_variable_size);
 225         spin_unlock(&efi_runtime_lock);
 226         return status;
 227 }
 228
 229 static efi_status_t virt_efi_get_next_high_mono_count(u32 *count)
 230 {
 231         efi_status_t status;
 232
 233         spin_lock(&efi_runtime_lock);
 234         status = efi_call_virt(get_next_high_mono_count, count);
 235         spin_unlock(&efi_runtime_lock);
 236         return status;
 237 }
 238
 239 static void virt_efi_reset_system(int reset_type,
 240                                   efi_status_t status,
 241                                   unsigned long data_size,
 242                                   efi_char16_t *data)
 243 {
 244         spin_lock(&efi_runtime_lock);
 245         __efi_call_virt(reset_system, reset_type, status, data_size, data);
 246         spin_unlock(&efi_runtime_lock);
 247 }
 248
 249 static efi_status_t virt_efi_update_capsule(efi_capsule_header_t **capsules,
 250                                             unsigned long count,
 251                                             unsigned long sg_list)
 252 {
 253         efi_status_t status;
 254
 255         if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
 256                 return EFI_UNSUPPORTED;
 257
 258         spin_lock(&efi_runtime_lock);
 259         status = efi_call_virt(update_capsule, capsules, count, sg_list);
 260         spin_unlock(&efi_runtime_lock);
 261         return status;
 262 }
 263
 264 static efi_status_t virt_efi_query_capsule_caps(efi_capsule_header_t **capsules,
 265                                                 unsigned long count,
 266                                                 u64 *max_size,
 267                                                 int *reset_type)
 268 {
 269         efi_status_t status;
 270
 271         if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
 272                 return EFI_UNSUPPORTED;
 273
 274         spin_lock(&efi_runtime_lock);
 275         status = efi_call_virt(query_capsule_caps, capsules, count, max_size,
 276                                reset_type);
 277         spin_unlock(&efi_runtime_lock);
 278         return status;
 279 }
 280
 281 void efi_native_runtime_setup(void)
 282 {
 283         efi.get_time = virt_efi_get_time;
 284         efi.set_time = virt_efi_set_time;
 285         efi.get_wakeup_time = virt_efi_get_wakeup_time;
 286         efi.set_wakeup_time = virt_efi_set_wakeup_time;
 287         efi.get_variable = virt_efi_get_variable;
 288         efi.get_next_variable = virt_efi_get_next_variable;
 289         efi.set_variable = virt_efi_set_variable;
 290         efi.set_variable_nonblocking = virt_efi_set_variable_nonblocking;
 291         efi.get_next_high_mono_count = virt_efi_get_next_high_mono_count;
 292         efi.reset_system = virt_efi_reset_system;
 293         efi.query_variable_info = virt_efi_query_variable_info;
 294         efi.query_variable_info_nonblocking = virt_efi_query_variable_info_nonblocking;
 295         efi.update_capsule = virt_efi_update_capsule;
 296         efi.query_capsule_caps = virt_efi_query_capsule_caps;
 297 }