1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * runtime-wrappers.c - Runtime Services function call wrappers 4 * 5 * Implementation summary: 6 * ----------------------- 7 * 1. When user/kernel thread requests to execute efi_runtime_service(), 8 * enqueue work to efi_rts_wq. 9 * 2. Caller thread waits for completion until the work is finished 10 * because it's dependent on the return status and execution of 11 * efi_runtime_service(). 12 * For instance, get_variable() and get_next_variable(). 13 * 14 * Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.org> 15 * 16 * Split off from arch/x86/platform/efi/efi.c 17 * 18 * Copyright (C) 1999 VA Linux Systems 19 * Copyright (C) 1999 Walt Drummond <drummond@valinux.com> 20 * Copyright (C) 1999-2002 Hewlett-Packard Co. 21 * Copyright (C) 2005-2008 Intel Co. 22 * Copyright (C) 2013 SuSE Labs 23 */ 24 25 #define pr_fmt(fmt) "efi: " fmt 26 27 #include <linux/bug.h> 28 #include <linux/efi.h> 29 #include <linux/irqflags.h> 30 #include <linux/mutex.h> 31 #include <linux/semaphore.h> 32 #include <linux/stringify.h> 33 #include <linux/workqueue.h> 34 #include <linux/completion.h> 35 36 #include <asm/efi.h> 37 38 /* 39 * Wrap around the new efi_call_virt_generic() macros so that the 40 * code doesn't get too cluttered: 41 */ 42 #define efi_call_virt(f, args...) \ 43 efi_call_virt_pointer(efi.runtime, f, args) 44 #define __efi_call_virt(f, args...) \ 45 __efi_call_virt_pointer(efi.runtime, f, args) 46 47 struct efi_runtime_work efi_rts_work; 48 49 /* 50 * efi_queue_work: Queue efi_runtime_service() and wait until it's done 51 * @rts: efi_runtime_service() function identifier 52 * @rts_arg<1-5>: efi_runtime_service() function arguments 53 * 54 * Accesses to efi_runtime_services() are serialized by a binary 55 * semaphore (efi_runtime_lock) and caller waits until the work is 56 * finished, hence _only_ one work is queued at a time and the caller 57 * thread waits for completion. 58 */ 59 #define efi_queue_work(_rts, _arg1, _arg2, _arg3, _arg4, _arg5) \ 60 ({ \ 61 efi_rts_work.status = EFI_ABORTED; \ 62 \ 63 if (!efi_enabled(EFI_RUNTIME_SERVICES)) { \ 64 pr_warn_once("EFI Runtime Services are disabled!\n"); \ 65 efi_rts_work.status = EFI_DEVICE_ERROR; \ 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 WARN_ON_ONCE(efi_rts_work.status == EFI_ABORTED); \ 88 exit: \ 89 efi_rts_work.efi_rts_id = EFI_NONE; \ 90 efi_rts_work.status; \ 91 }) 92 93 #ifndef arch_efi_save_flags 94 #define arch_efi_save_flags(state_flags) local_save_flags(state_flags) 95 #define arch_efi_restore_flags(state_flags) local_irq_restore(state_flags) 96 #endif 97 98 unsigned long efi_call_virt_save_flags(void) 99 { 100 unsigned long flags; 101 102 arch_efi_save_flags(flags); 103 return flags; 104 } 105 106 void efi_call_virt_check_flags(unsigned long flags, const char *call) 107 { 108 unsigned long cur_flags, mismatch; 109 110 cur_flags = efi_call_virt_save_flags(); 111 112 mismatch = flags ^ cur_flags; 113 if (!WARN_ON_ONCE(mismatch & ARCH_EFI_IRQ_FLAGS_MASK)) 114 return; 115 116 add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_NOW_UNRELIABLE); 117 pr_err_ratelimited(FW_BUG "IRQ flags corrupted (0x%08lx=>0x%08lx) by EFI %s\n", 118 flags, cur_flags, call); 119 arch_efi_restore_flags(flags); 120 } 121 122 /* 123 * According to section 7.1 of the UEFI spec, Runtime Services are not fully 124 * reentrant, and there are particular combinations of calls that need to be 125 * serialized. (source: UEFI Specification v2.4A) 126 * 127 * Table 31. Rules for Reentry Into Runtime Services 128 * +------------------------------------+-------------------------------+ 129 * | If previous call is busy in | Forbidden to call | 130 * +------------------------------------+-------------------------------+ 131 * | Any | SetVirtualAddressMap() | 132 * +------------------------------------+-------------------------------+ 133 * | ConvertPointer() | ConvertPointer() | 134 * +------------------------------------+-------------------------------+ 135 * | SetVariable() | ResetSystem() | 136 * | UpdateCapsule() | | 137 * | SetTime() | | 138 * | SetWakeupTime() | | 139 * | GetNextHighMonotonicCount() | | 140 * +------------------------------------+-------------------------------+ 141 * | GetVariable() | GetVariable() | 142 * | GetNextVariableName() | GetNextVariableName() | 143 * | SetVariable() | SetVariable() | 144 * | QueryVariableInfo() | QueryVariableInfo() | 145 * | UpdateCapsule() | UpdateCapsule() | 146 * | QueryCapsuleCapabilities() | QueryCapsuleCapabilities() | 147 * | GetNextHighMonotonicCount() | GetNextHighMonotonicCount() | 148 * +------------------------------------+-------------------------------+ 149 * | GetTime() | GetTime() | 150 * | SetTime() | SetTime() | 151 * | GetWakeupTime() | GetWakeupTime() | 152 * | SetWakeupTime() | SetWakeupTime() | 153 * +------------------------------------+-------------------------------+ 154 * 155 * Due to the fact that the EFI pstore may write to the variable store in 156 * interrupt context, we need to use a lock for at least the groups that 157 * contain SetVariable() and QueryVariableInfo(). That leaves little else, as 158 * none of the remaining functions are actually ever called at runtime. 159 * So let's just use a single lock to serialize all Runtime Services calls. 160 */ 161 static DEFINE_SEMAPHORE(efi_runtime_lock, 1); 162 163 /* 164 * Expose the EFI runtime lock to the UV platform 165 */ 166 #ifdef CONFIG_X86_UV 167 extern struct semaphore __efi_uv_runtime_lock __alias(efi_runtime_lock); 168 #endif 169 170 /* 171 * Calls the appropriate efi_runtime_service() with the appropriate 172 * arguments. 173 * 174 * Semantics followed by efi_call_rts() to understand efi_runtime_work: 175 * 1. If argument was a pointer, recast it from void pointer to original 176 * pointer type. 177 * 2. If argument was a value, recast it from void pointer to original 178 * pointer type and dereference it. 179 */ 180 static void efi_call_rts(struct work_struct *work) 181 { 182 void *arg1, *arg2, *arg3, *arg4, *arg5; 183 efi_status_t status = EFI_NOT_FOUND; 184 185 arg1 = efi_rts_work.arg1; 186 arg2 = efi_rts_work.arg2; 187 arg3 = efi_rts_work.arg3; 188 arg4 = efi_rts_work.arg4; 189 arg5 = efi_rts_work.arg5; 190 191 switch (efi_rts_work.efi_rts_id) { 192 case EFI_GET_TIME: 193 status = efi_call_virt(get_time, (efi_time_t *)arg1, 194 (efi_time_cap_t *)arg2); 195 break; 196 case EFI_SET_TIME: 197 status = efi_call_virt(set_time, (efi_time_t *)arg1); 198 break; 199 case EFI_GET_WAKEUP_TIME: 200 status = efi_call_virt(get_wakeup_time, (efi_bool_t *)arg1, 201 (efi_bool_t *)arg2, (efi_time_t *)arg3); 202 break; 203 case EFI_SET_WAKEUP_TIME: 204 status = efi_call_virt(set_wakeup_time, *(efi_bool_t *)arg1, 205 (efi_time_t *)arg2); 206 break; 207 case EFI_GET_VARIABLE: 208 status = efi_call_virt(get_variable, (efi_char16_t *)arg1, 209 (efi_guid_t *)arg2, (u32 *)arg3, 210 (unsigned long *)arg4, (void *)arg5); 211 break; 212 case EFI_GET_NEXT_VARIABLE: 213 status = efi_call_virt(get_next_variable, (unsigned long *)arg1, 214 (efi_char16_t *)arg2, 215 (efi_guid_t *)arg3); 216 break; 217 case EFI_SET_VARIABLE: 218 status = efi_call_virt(set_variable, (efi_char16_t *)arg1, 219 (efi_guid_t *)arg2, *(u32 *)arg3, 220 *(unsigned long *)arg4, (void *)arg5); 221 break; 222 case EFI_QUERY_VARIABLE_INFO: 223 status = efi_call_virt(query_variable_info, *(u32 *)arg1, 224 (u64 *)arg2, (u64 *)arg3, (u64 *)arg4); 225 break; 226 case EFI_GET_NEXT_HIGH_MONO_COUNT: 227 status = efi_call_virt(get_next_high_mono_count, (u32 *)arg1); 228 break; 229 case EFI_UPDATE_CAPSULE: 230 status = efi_call_virt(update_capsule, 231 (efi_capsule_header_t **)arg1, 232 *(unsigned long *)arg2, 233 *(unsigned long *)arg3); 234 break; 235 case EFI_QUERY_CAPSULE_CAPS: 236 status = efi_call_virt(query_capsule_caps, 237 (efi_capsule_header_t **)arg1, 238 *(unsigned long *)arg2, (u64 *)arg3, 239 (int *)arg4); 240 break; 241 default: 242 /* 243 * Ideally, we should never reach here because a caller of this 244 * function should have put the right efi_runtime_service() 245 * function identifier into efi_rts_work->efi_rts_id 246 */ 247 pr_err("Requested executing invalid EFI Runtime Service.\n"); 248 } 249 efi_rts_work.status = status; 250 complete(&efi_rts_work.efi_rts_comp); 251 } 252 253 static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc) 254 { 255 efi_status_t status; 256 257 if (down_interruptible(&efi_runtime_lock)) 258 return EFI_ABORTED; 259 status = efi_queue_work(EFI_GET_TIME, tm, tc, NULL, NULL, NULL); 260 up(&efi_runtime_lock); 261 return status; 262 } 263 264 static efi_status_t virt_efi_set_time(efi_time_t *tm) 265 { 266 efi_status_t status; 267 268 if (down_interruptible(&efi_runtime_lock)) 269 return EFI_ABORTED; 270 status = efi_queue_work(EFI_SET_TIME, tm, NULL, NULL, NULL, NULL); 271 up(&efi_runtime_lock); 272 return status; 273 } 274 275 static efi_status_t virt_efi_get_wakeup_time(efi_bool_t *enabled, 276 efi_bool_t *pending, 277 efi_time_t *tm) 278 { 279 efi_status_t status; 280 281 if (down_interruptible(&efi_runtime_lock)) 282 return EFI_ABORTED; 283 status = efi_queue_work(EFI_GET_WAKEUP_TIME, enabled, pending, tm, NULL, 284 NULL); 285 up(&efi_runtime_lock); 286 return status; 287 } 288 289 static efi_status_t virt_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm) 290 { 291 efi_status_t status; 292 293 if (down_interruptible(&efi_runtime_lock)) 294 return EFI_ABORTED; 295 status = efi_queue_work(EFI_SET_WAKEUP_TIME, &enabled, tm, NULL, NULL, 296 NULL); 297 up(&efi_runtime_lock); 298 return status; 299 } 300 301 static efi_status_t virt_efi_get_variable(efi_char16_t *name, 302 efi_guid_t *vendor, 303 u32 *attr, 304 unsigned long *data_size, 305 void *data) 306 { 307 efi_status_t status; 308 309 if (down_interruptible(&efi_runtime_lock)) 310 return EFI_ABORTED; 311 status = efi_queue_work(EFI_GET_VARIABLE, name, vendor, attr, data_size, 312 data); 313 up(&efi_runtime_lock); 314 return status; 315 } 316 317 static efi_status_t virt_efi_get_next_variable(unsigned long *name_size, 318 efi_char16_t *name, 319 efi_guid_t *vendor) 320 { 321 efi_status_t status; 322 323 if (down_interruptible(&efi_runtime_lock)) 324 return EFI_ABORTED; 325 status = efi_queue_work(EFI_GET_NEXT_VARIABLE, name_size, name, vendor, 326 NULL, NULL); 327 up(&efi_runtime_lock); 328 return status; 329 } 330 331 static efi_status_t virt_efi_set_variable(efi_char16_t *name, 332 efi_guid_t *vendor, 333 u32 attr, 334 unsigned long data_size, 335 void *data) 336 { 337 efi_status_t status; 338 339 if (down_interruptible(&efi_runtime_lock)) 340 return EFI_ABORTED; 341 status = efi_queue_work(EFI_SET_VARIABLE, name, vendor, &attr, &data_size, 342 data); 343 up(&efi_runtime_lock); 344 return status; 345 } 346 347 static efi_status_t 348 virt_efi_set_variable_nonblocking(efi_char16_t *name, efi_guid_t *vendor, 349 u32 attr, unsigned long data_size, 350 void *data) 351 { 352 efi_status_t status; 353 354 if (down_trylock(&efi_runtime_lock)) 355 return EFI_NOT_READY; 356 357 status = efi_call_virt(set_variable, name, vendor, attr, data_size, 358 data); 359 up(&efi_runtime_lock); 360 return status; 361 } 362 363 364 static efi_status_t virt_efi_query_variable_info(u32 attr, 365 u64 *storage_space, 366 u64 *remaining_space, 367 u64 *max_variable_size) 368 { 369 efi_status_t status; 370 371 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) 372 return EFI_UNSUPPORTED; 373 374 if (down_interruptible(&efi_runtime_lock)) 375 return EFI_ABORTED; 376 status = efi_queue_work(EFI_QUERY_VARIABLE_INFO, &attr, storage_space, 377 remaining_space, max_variable_size, NULL); 378 up(&efi_runtime_lock); 379 return status; 380 } 381 382 static efi_status_t 383 virt_efi_query_variable_info_nonblocking(u32 attr, 384 u64 *storage_space, 385 u64 *remaining_space, 386 u64 *max_variable_size) 387 { 388 efi_status_t status; 389 390 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) 391 return EFI_UNSUPPORTED; 392 393 if (down_trylock(&efi_runtime_lock)) 394 return EFI_NOT_READY; 395 396 status = efi_call_virt(query_variable_info, attr, storage_space, 397 remaining_space, max_variable_size); 398 up(&efi_runtime_lock); 399 return status; 400 } 401 402 static efi_status_t virt_efi_get_next_high_mono_count(u32 *count) 403 { 404 efi_status_t status; 405 406 if (down_interruptible(&efi_runtime_lock)) 407 return EFI_ABORTED; 408 status = efi_queue_work(EFI_GET_NEXT_HIGH_MONO_COUNT, count, NULL, NULL, 409 NULL, NULL); 410 up(&efi_runtime_lock); 411 return status; 412 } 413 414 static void virt_efi_reset_system(int reset_type, 415 efi_status_t status, 416 unsigned long data_size, 417 efi_char16_t *data) 418 { 419 if (down_trylock(&efi_runtime_lock)) { 420 pr_warn("failed to invoke the reset_system() runtime service:\n" 421 "could not get exclusive access to the firmware\n"); 422 return; 423 } 424 efi_rts_work.efi_rts_id = EFI_RESET_SYSTEM; 425 __efi_call_virt(reset_system, reset_type, status, data_size, data); 426 up(&efi_runtime_lock); 427 } 428 429 static efi_status_t virt_efi_update_capsule(efi_capsule_header_t **capsules, 430 unsigned long count, 431 unsigned long sg_list) 432 { 433 efi_status_t status; 434 435 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) 436 return EFI_UNSUPPORTED; 437 438 if (down_interruptible(&efi_runtime_lock)) 439 return EFI_ABORTED; 440 status = efi_queue_work(EFI_UPDATE_CAPSULE, capsules, &count, &sg_list, 441 NULL, NULL); 442 up(&efi_runtime_lock); 443 return status; 444 } 445 446 static efi_status_t virt_efi_query_capsule_caps(efi_capsule_header_t **capsules, 447 unsigned long count, 448 u64 *max_size, 449 int *reset_type) 450 { 451 efi_status_t status; 452 453 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) 454 return EFI_UNSUPPORTED; 455 456 if (down_interruptible(&efi_runtime_lock)) 457 return EFI_ABORTED; 458 status = efi_queue_work(EFI_QUERY_CAPSULE_CAPS, capsules, &count, 459 max_size, reset_type, NULL); 460 up(&efi_runtime_lock); 461 return status; 462 } 463 464 void efi_native_runtime_setup(void) 465 { 466 efi.get_time = virt_efi_get_time; 467 efi.set_time = virt_efi_set_time; 468 efi.get_wakeup_time = virt_efi_get_wakeup_time; 469 efi.set_wakeup_time = virt_efi_set_wakeup_time; 470 efi.get_variable = virt_efi_get_variable; 471 efi.get_next_variable = virt_efi_get_next_variable; 472 efi.set_variable = virt_efi_set_variable; 473 efi.set_variable_nonblocking = virt_efi_set_variable_nonblocking; 474 efi.get_next_high_mono_count = virt_efi_get_next_high_mono_count; 475 efi.reset_system = virt_efi_reset_system; 476 efi.query_variable_info = virt_efi_query_variable_info; 477 efi.query_variable_info_nonblocking = virt_efi_query_variable_info_nonblocking; 478 efi.update_capsule = virt_efi_update_capsule; 479 efi.query_capsule_caps = virt_efi_query_capsule_caps; 480 } 481