1 /* 2 * runtime-wrappers.c - Runtime Services function call wrappers 3 * 4 * Implementation summary: 5 * ----------------------- 6 * 1. When user/kernel thread requests to execute efi_runtime_service(), 7 * enqueue work to efi_rts_wq. 8 * 2. Caller thread waits for completion until the work is finished 9 * because it's dependent on the return status and execution of 10 * efi_runtime_service(). 11 * For instance, get_variable() and get_next_variable(). 12 * 13 * Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.org> 14 * 15 * Split off from arch/x86/platform/efi/efi.c 16 * 17 * Copyright (C) 1999 VA Linux Systems 18 * Copyright (C) 1999 Walt Drummond <drummond@valinux.com> 19 * Copyright (C) 1999-2002 Hewlett-Packard Co. 20 * Copyright (C) 2005-2008 Intel Co. 21 * Copyright (C) 2013 SuSE Labs 22 * 23 * This file is released under the GPLv2. 24 */ 25 26 #define pr_fmt(fmt) "efi: " fmt 27 28 #include <linux/bug.h> 29 #include <linux/efi.h> 30 #include <linux/irqflags.h> 31 #include <linux/mutex.h> 32 #include <linux/semaphore.h> 33 #include <linux/stringify.h> 34 #include <linux/workqueue.h> 35 #include <linux/completion.h> 36 37 #include <asm/efi.h> 38 39 /* 40 * Wrap around the new efi_call_virt_generic() macros so that the 41 * code doesn't get too cluttered: 42 */ 43 #define efi_call_virt(f, args...) \ 44 efi_call_virt_pointer(efi.systab->runtime, f, args) 45 #define __efi_call_virt(f, args...) \ 46 __efi_call_virt_pointer(efi.systab->runtime, f, args) 47 48 struct efi_runtime_work efi_rts_work; 49 50 /* 51 * efi_queue_work: Queue efi_runtime_service() and wait until it's done 52 * @rts: efi_runtime_service() function identifier 53 * @rts_arg<1-5>: efi_runtime_service() function arguments 54 * 55 * Accesses to efi_runtime_services() are serialized by a binary 56 * semaphore (efi_runtime_lock) and caller waits until the work is 57 * finished, hence _only_ one work is queued at a time and the caller 58 * thread waits for completion. 59 */ 60 #define efi_queue_work(_rts, _arg1, _arg2, _arg3, _arg4, _arg5) \ 61 ({ \ 62 efi_rts_work.status = EFI_ABORTED; \ 63 \ 64 if (!efi_enabled(EFI_RUNTIME_SERVICES)) { \ 65 pr_warn_once("EFI Runtime Services are disabled!\n"); \ 66 goto exit; \ 67 } \ 68 \ 69 init_completion(&efi_rts_work.efi_rts_comp); \ 70 INIT_WORK(&efi_rts_work.work, efi_call_rts); \ 71 efi_rts_work.arg1 = _arg1; \ 72 efi_rts_work.arg2 = _arg2; \ 73 efi_rts_work.arg3 = _arg3; \ 74 efi_rts_work.arg4 = _arg4; \ 75 efi_rts_work.arg5 = _arg5; \ 76 efi_rts_work.efi_rts_id = _rts; \ 77 \ 78 /* \ 79 * queue_work() returns 0 if work was already on queue, \ 80 * _ideally_ this should never happen. \ 81 */ \ 82 if (queue_work(efi_rts_wq, &efi_rts_work.work)) \ 83 wait_for_completion(&efi_rts_work.efi_rts_comp); \ 84 else \ 85 pr_err("Failed to queue work to efi_rts_wq.\n"); \ 86 \ 87 exit: \ 88 efi_rts_work.efi_rts_id = NONE; \ 89 efi_rts_work.status; \ 90 }) 91 92 void efi_call_virt_check_flags(unsigned long flags, const char *call) 93 { 94 unsigned long cur_flags, mismatch; 95 96 local_save_flags(cur_flags); 97 98 mismatch = flags ^ cur_flags; 99 if (!WARN_ON_ONCE(mismatch & ARCH_EFI_IRQ_FLAGS_MASK)) 100 return; 101 102 add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_NOW_UNRELIABLE); 103 pr_err_ratelimited(FW_BUG "IRQ flags corrupted (0x%08lx=>0x%08lx) by EFI %s\n", 104 flags, cur_flags, call); 105 local_irq_restore(flags); 106 } 107 108 /* 109 * According to section 7.1 of the UEFI spec, Runtime Services are not fully 110 * reentrant, and there are particular combinations of calls that need to be 111 * serialized. (source: UEFI Specification v2.4A) 112 * 113 * Table 31. Rules for Reentry Into Runtime Services 114 * +------------------------------------+-------------------------------+ 115 * | If previous call is busy in | Forbidden to call | 116 * +------------------------------------+-------------------------------+ 117 * | Any | SetVirtualAddressMap() | 118 * +------------------------------------+-------------------------------+ 119 * | ConvertPointer() | ConvertPointer() | 120 * +------------------------------------+-------------------------------+ 121 * | SetVariable() | ResetSystem() | 122 * | UpdateCapsule() | | 123 * | SetTime() | | 124 * | SetWakeupTime() | | 125 * | GetNextHighMonotonicCount() | | 126 * +------------------------------------+-------------------------------+ 127 * | GetVariable() | GetVariable() | 128 * | GetNextVariableName() | GetNextVariableName() | 129 * | SetVariable() | SetVariable() | 130 * | QueryVariableInfo() | QueryVariableInfo() | 131 * | UpdateCapsule() | UpdateCapsule() | 132 * | QueryCapsuleCapabilities() | QueryCapsuleCapabilities() | 133 * | GetNextHighMonotonicCount() | GetNextHighMonotonicCount() | 134 * +------------------------------------+-------------------------------+ 135 * | GetTime() | GetTime() | 136 * | SetTime() | SetTime() | 137 * | GetWakeupTime() | GetWakeupTime() | 138 * | SetWakeupTime() | SetWakeupTime() | 139 * +------------------------------------+-------------------------------+ 140 * 141 * Due to the fact that the EFI pstore may write to the variable store in 142 * interrupt context, we need to use a lock for at least the groups that 143 * contain SetVariable() and QueryVariableInfo(). That leaves little else, as 144 * none of the remaining functions are actually ever called at runtime. 145 * So let's just use a single lock to serialize all Runtime Services calls. 146 */ 147 static DEFINE_SEMAPHORE(efi_runtime_lock); 148 149 /* 150 * Expose the EFI runtime lock to the UV platform 151 */ 152 #ifdef CONFIG_X86_UV 153 extern struct semaphore __efi_uv_runtime_lock __alias(efi_runtime_lock); 154 #endif 155 156 /* 157 * Calls the appropriate efi_runtime_service() with the appropriate 158 * arguments. 159 * 160 * Semantics followed by efi_call_rts() to understand efi_runtime_work: 161 * 1. If argument was a pointer, recast it from void pointer to original 162 * pointer type. 163 * 2. If argument was a value, recast it from void pointer to original 164 * pointer type and dereference it. 165 */ 166 static void efi_call_rts(struct work_struct *work) 167 { 168 void *arg1, *arg2, *arg3, *arg4, *arg5; 169 efi_status_t status = EFI_NOT_FOUND; 170 171 arg1 = efi_rts_work.arg1; 172 arg2 = efi_rts_work.arg2; 173 arg3 = efi_rts_work.arg3; 174 arg4 = efi_rts_work.arg4; 175 arg5 = efi_rts_work.arg5; 176 177 switch (efi_rts_work.efi_rts_id) { 178 case GET_TIME: 179 status = efi_call_virt(get_time, (efi_time_t *)arg1, 180 (efi_time_cap_t *)arg2); 181 break; 182 case SET_TIME: 183 status = efi_call_virt(set_time, (efi_time_t *)arg1); 184 break; 185 case GET_WAKEUP_TIME: 186 status = efi_call_virt(get_wakeup_time, (efi_bool_t *)arg1, 187 (efi_bool_t *)arg2, (efi_time_t *)arg3); 188 break; 189 case SET_WAKEUP_TIME: 190 status = efi_call_virt(set_wakeup_time, *(efi_bool_t *)arg1, 191 (efi_time_t *)arg2); 192 break; 193 case GET_VARIABLE: 194 status = efi_call_virt(get_variable, (efi_char16_t *)arg1, 195 (efi_guid_t *)arg2, (u32 *)arg3, 196 (unsigned long *)arg4, (void *)arg5); 197 break; 198 case GET_NEXT_VARIABLE: 199 status = efi_call_virt(get_next_variable, (unsigned long *)arg1, 200 (efi_char16_t *)arg2, 201 (efi_guid_t *)arg3); 202 break; 203 case SET_VARIABLE: 204 status = efi_call_virt(set_variable, (efi_char16_t *)arg1, 205 (efi_guid_t *)arg2, *(u32 *)arg3, 206 *(unsigned long *)arg4, (void *)arg5); 207 break; 208 case QUERY_VARIABLE_INFO: 209 status = efi_call_virt(query_variable_info, *(u32 *)arg1, 210 (u64 *)arg2, (u64 *)arg3, (u64 *)arg4); 211 break; 212 case GET_NEXT_HIGH_MONO_COUNT: 213 status = efi_call_virt(get_next_high_mono_count, (u32 *)arg1); 214 break; 215 case UPDATE_CAPSULE: 216 status = efi_call_virt(update_capsule, 217 (efi_capsule_header_t **)arg1, 218 *(unsigned long *)arg2, 219 *(unsigned long *)arg3); 220 break; 221 case QUERY_CAPSULE_CAPS: 222 status = efi_call_virt(query_capsule_caps, 223 (efi_capsule_header_t **)arg1, 224 *(unsigned long *)arg2, (u64 *)arg3, 225 (int *)arg4); 226 break; 227 default: 228 /* 229 * Ideally, we should never reach here because a caller of this 230 * function should have put the right efi_runtime_service() 231 * function identifier into efi_rts_work->efi_rts_id 232 */ 233 pr_err("Requested executing invalid EFI Runtime Service.\n"); 234 } 235 efi_rts_work.status = status; 236 complete(&efi_rts_work.efi_rts_comp); 237 } 238 239 static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc) 240 { 241 efi_status_t status; 242 243 if (down_interruptible(&efi_runtime_lock)) 244 return EFI_ABORTED; 245 status = efi_queue_work(GET_TIME, tm, tc, NULL, NULL, NULL); 246 up(&efi_runtime_lock); 247 return status; 248 } 249 250 static efi_status_t virt_efi_set_time(efi_time_t *tm) 251 { 252 efi_status_t status; 253 254 if (down_interruptible(&efi_runtime_lock)) 255 return EFI_ABORTED; 256 status = efi_queue_work(SET_TIME, tm, NULL, NULL, NULL, NULL); 257 up(&efi_runtime_lock); 258 return status; 259 } 260 261 static efi_status_t virt_efi_get_wakeup_time(efi_bool_t *enabled, 262 efi_bool_t *pending, 263 efi_time_t *tm) 264 { 265 efi_status_t status; 266 267 if (down_interruptible(&efi_runtime_lock)) 268 return EFI_ABORTED; 269 status = efi_queue_work(GET_WAKEUP_TIME, enabled, pending, tm, NULL, 270 NULL); 271 up(&efi_runtime_lock); 272 return status; 273 } 274 275 static efi_status_t virt_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm) 276 { 277 efi_status_t status; 278 279 if (down_interruptible(&efi_runtime_lock)) 280 return EFI_ABORTED; 281 status = efi_queue_work(SET_WAKEUP_TIME, &enabled, tm, NULL, NULL, 282 NULL); 283 up(&efi_runtime_lock); 284 return status; 285 } 286 287 static efi_status_t virt_efi_get_variable(efi_char16_t *name, 288 efi_guid_t *vendor, 289 u32 *attr, 290 unsigned long *data_size, 291 void *data) 292 { 293 efi_status_t status; 294 295 if (down_interruptible(&efi_runtime_lock)) 296 return EFI_ABORTED; 297 status = efi_queue_work(GET_VARIABLE, name, vendor, attr, data_size, 298 data); 299 up(&efi_runtime_lock); 300 return status; 301 } 302 303 static efi_status_t virt_efi_get_next_variable(unsigned long *name_size, 304 efi_char16_t *name, 305 efi_guid_t *vendor) 306 { 307 efi_status_t status; 308 309 if (down_interruptible(&efi_runtime_lock)) 310 return EFI_ABORTED; 311 status = efi_queue_work(GET_NEXT_VARIABLE, name_size, name, vendor, 312 NULL, NULL); 313 up(&efi_runtime_lock); 314 return status; 315 } 316 317 static efi_status_t virt_efi_set_variable(efi_char16_t *name, 318 efi_guid_t *vendor, 319 u32 attr, 320 unsigned long data_size, 321 void *data) 322 { 323 efi_status_t status; 324 325 if (down_interruptible(&efi_runtime_lock)) 326 return EFI_ABORTED; 327 status = efi_queue_work(SET_VARIABLE, name, vendor, &attr, &data_size, 328 data); 329 up(&efi_runtime_lock); 330 return status; 331 } 332 333 static efi_status_t 334 virt_efi_set_variable_nonblocking(efi_char16_t *name, efi_guid_t *vendor, 335 u32 attr, unsigned long data_size, 336 void *data) 337 { 338 efi_status_t status; 339 340 if (down_trylock(&efi_runtime_lock)) 341 return EFI_NOT_READY; 342 343 status = efi_call_virt(set_variable, name, vendor, attr, data_size, 344 data); 345 up(&efi_runtime_lock); 346 return status; 347 } 348 349 350 static efi_status_t virt_efi_query_variable_info(u32 attr, 351 u64 *storage_space, 352 u64 *remaining_space, 353 u64 *max_variable_size) 354 { 355 efi_status_t status; 356 357 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) 358 return EFI_UNSUPPORTED; 359 360 if (down_interruptible(&efi_runtime_lock)) 361 return EFI_ABORTED; 362 status = efi_queue_work(QUERY_VARIABLE_INFO, &attr, storage_space, 363 remaining_space, max_variable_size, NULL); 364 up(&efi_runtime_lock); 365 return status; 366 } 367 368 static efi_status_t 369 virt_efi_query_variable_info_nonblocking(u32 attr, 370 u64 *storage_space, 371 u64 *remaining_space, 372 u64 *max_variable_size) 373 { 374 efi_status_t status; 375 376 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) 377 return EFI_UNSUPPORTED; 378 379 if (down_trylock(&efi_runtime_lock)) 380 return EFI_NOT_READY; 381 382 status = efi_call_virt(query_variable_info, attr, storage_space, 383 remaining_space, max_variable_size); 384 up(&efi_runtime_lock); 385 return status; 386 } 387 388 static efi_status_t virt_efi_get_next_high_mono_count(u32 *count) 389 { 390 efi_status_t status; 391 392 if (down_interruptible(&efi_runtime_lock)) 393 return EFI_ABORTED; 394 status = efi_queue_work(GET_NEXT_HIGH_MONO_COUNT, count, NULL, NULL, 395 NULL, NULL); 396 up(&efi_runtime_lock); 397 return status; 398 } 399 400 static void virt_efi_reset_system(int reset_type, 401 efi_status_t status, 402 unsigned long data_size, 403 efi_char16_t *data) 404 { 405 if (down_interruptible(&efi_runtime_lock)) { 406 pr_warn("failed to invoke the reset_system() runtime service:\n" 407 "could not get exclusive access to the firmware\n"); 408 return; 409 } 410 efi_rts_work.efi_rts_id = RESET_SYSTEM; 411 __efi_call_virt(reset_system, reset_type, status, data_size, data); 412 up(&efi_runtime_lock); 413 } 414 415 static efi_status_t virt_efi_update_capsule(efi_capsule_header_t **capsules, 416 unsigned long count, 417 unsigned long sg_list) 418 { 419 efi_status_t status; 420 421 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) 422 return EFI_UNSUPPORTED; 423 424 if (down_interruptible(&efi_runtime_lock)) 425 return EFI_ABORTED; 426 status = efi_queue_work(UPDATE_CAPSULE, capsules, &count, &sg_list, 427 NULL, NULL); 428 up(&efi_runtime_lock); 429 return status; 430 } 431 432 static efi_status_t virt_efi_query_capsule_caps(efi_capsule_header_t **capsules, 433 unsigned long count, 434 u64 *max_size, 435 int *reset_type) 436 { 437 efi_status_t status; 438 439 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) 440 return EFI_UNSUPPORTED; 441 442 if (down_interruptible(&efi_runtime_lock)) 443 return EFI_ABORTED; 444 status = efi_queue_work(QUERY_CAPSULE_CAPS, capsules, &count, 445 max_size, reset_type, NULL); 446 up(&efi_runtime_lock); 447 return status; 448 } 449 450 void efi_native_runtime_setup(void) 451 { 452 efi.get_time = virt_efi_get_time; 453 efi.set_time = virt_efi_set_time; 454 efi.get_wakeup_time = virt_efi_get_wakeup_time; 455 efi.set_wakeup_time = virt_efi_set_wakeup_time; 456 efi.get_variable = virt_efi_get_variable; 457 efi.get_next_variable = virt_efi_get_next_variable; 458 efi.set_variable = virt_efi_set_variable; 459 efi.set_variable_nonblocking = virt_efi_set_variable_nonblocking; 460 efi.get_next_high_mono_count = virt_efi_get_next_high_mono_count; 461 efi.reset_system = virt_efi_reset_system; 462 efi.query_variable_info = virt_efi_query_variable_info; 463 efi.query_variable_info_nonblocking = virt_efi_query_variable_info_nonblocking; 464 efi.update_capsule = virt_efi_update_capsule; 465 efi.query_capsule_caps = virt_efi_query_capsule_caps; 466 } 467