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 goto exit; \ 66 } \ 67 \ 68 init_completion(&efi_rts_work.efi_rts_comp); \ 69 INIT_WORK(&efi_rts_work.work, efi_call_rts); \ 70 efi_rts_work.arg1 = _arg1; \ 71 efi_rts_work.arg2 = _arg2; \ 72 efi_rts_work.arg3 = _arg3; \ 73 efi_rts_work.arg4 = _arg4; \ 74 efi_rts_work.arg5 = _arg5; \ 75 efi_rts_work.efi_rts_id = _rts; \ 76 \ 77 /* \ 78 * queue_work() returns 0 if work was already on queue, \ 79 * _ideally_ this should never happen. \ 80 */ \ 81 if (queue_work(efi_rts_wq, &efi_rts_work.work)) \ 82 wait_for_completion(&efi_rts_work.efi_rts_comp); \ 83 else \ 84 pr_err("Failed to queue work to efi_rts_wq.\n"); \ 85 \ 86 WARN_ON_ONCE(efi_rts_work.status == EFI_ABORTED); \ 87 exit: \ 88 efi_rts_work.efi_rts_id = EFI_NONE; \ 89 efi_rts_work.status; \ 90 }) 91 92 #ifndef arch_efi_save_flags 93 #define arch_efi_save_flags(state_flags) local_save_flags(state_flags) 94 #define arch_efi_restore_flags(state_flags) local_irq_restore(state_flags) 95 #endif 96 97 unsigned long efi_call_virt_save_flags(void) 98 { 99 unsigned long flags; 100 101 arch_efi_save_flags(flags); 102 return flags; 103 } 104 105 void efi_call_virt_check_flags(unsigned long flags, const char *call) 106 { 107 unsigned long cur_flags, mismatch; 108 109 cur_flags = efi_call_virt_save_flags(); 110 111 mismatch = flags ^ cur_flags; 112 if (!WARN_ON_ONCE(mismatch & ARCH_EFI_IRQ_FLAGS_MASK)) 113 return; 114 115 add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_NOW_UNRELIABLE); 116 pr_err_ratelimited(FW_BUG "IRQ flags corrupted (0x%08lx=>0x%08lx) by EFI %s\n", 117 flags, cur_flags, call); 118 arch_efi_restore_flags(flags); 119 } 120 121 /* 122 * According to section 7.1 of the UEFI spec, Runtime Services are not fully 123 * reentrant, and there are particular combinations of calls that need to be 124 * serialized. (source: UEFI Specification v2.4A) 125 * 126 * Table 31. Rules for Reentry Into Runtime Services 127 * +------------------------------------+-------------------------------+ 128 * | If previous call is busy in | Forbidden to call | 129 * +------------------------------------+-------------------------------+ 130 * | Any | SetVirtualAddressMap() | 131 * +------------------------------------+-------------------------------+ 132 * | ConvertPointer() | ConvertPointer() | 133 * +------------------------------------+-------------------------------+ 134 * | SetVariable() | ResetSystem() | 135 * | UpdateCapsule() | | 136 * | SetTime() | | 137 * | SetWakeupTime() | | 138 * | GetNextHighMonotonicCount() | | 139 * +------------------------------------+-------------------------------+ 140 * | GetVariable() | GetVariable() | 141 * | GetNextVariableName() | GetNextVariableName() | 142 * | SetVariable() | SetVariable() | 143 * | QueryVariableInfo() | QueryVariableInfo() | 144 * | UpdateCapsule() | UpdateCapsule() | 145 * | QueryCapsuleCapabilities() | QueryCapsuleCapabilities() | 146 * | GetNextHighMonotonicCount() | GetNextHighMonotonicCount() | 147 * +------------------------------------+-------------------------------+ 148 * | GetTime() | GetTime() | 149 * | SetTime() | SetTime() | 150 * | GetWakeupTime() | GetWakeupTime() | 151 * | SetWakeupTime() | SetWakeupTime() | 152 * +------------------------------------+-------------------------------+ 153 * 154 * Due to the fact that the EFI pstore may write to the variable store in 155 * interrupt context, we need to use a lock for at least the groups that 156 * contain SetVariable() and QueryVariableInfo(). That leaves little else, as 157 * none of the remaining functions are actually ever called at runtime. 158 * So let's just use a single lock to serialize all Runtime Services calls. 159 */ 160 static DEFINE_SEMAPHORE(efi_runtime_lock); 161 162 /* 163 * Expose the EFI runtime lock to the UV platform 164 */ 165 #ifdef CONFIG_X86_UV 166 extern struct semaphore __efi_uv_runtime_lock __alias(efi_runtime_lock); 167 #endif 168 169 /* 170 * Calls the appropriate efi_runtime_service() with the appropriate 171 * arguments. 172 * 173 * Semantics followed by efi_call_rts() to understand efi_runtime_work: 174 * 1. If argument was a pointer, recast it from void pointer to original 175 * pointer type. 176 * 2. If argument was a value, recast it from void pointer to original 177 * pointer type and dereference it. 178 */ 179 static void efi_call_rts(struct work_struct *work) 180 { 181 void *arg1, *arg2, *arg3, *arg4, *arg5; 182 efi_status_t status = EFI_NOT_FOUND; 183 184 arg1 = efi_rts_work.arg1; 185 arg2 = efi_rts_work.arg2; 186 arg3 = efi_rts_work.arg3; 187 arg4 = efi_rts_work.arg4; 188 arg5 = efi_rts_work.arg5; 189 190 switch (efi_rts_work.efi_rts_id) { 191 case EFI_GET_TIME: 192 status = efi_call_virt(get_time, (efi_time_t *)arg1, 193 (efi_time_cap_t *)arg2); 194 break; 195 case EFI_SET_TIME: 196 status = efi_call_virt(set_time, (efi_time_t *)arg1); 197 break; 198 case EFI_GET_WAKEUP_TIME: 199 status = efi_call_virt(get_wakeup_time, (efi_bool_t *)arg1, 200 (efi_bool_t *)arg2, (efi_time_t *)arg3); 201 break; 202 case EFI_SET_WAKEUP_TIME: 203 status = efi_call_virt(set_wakeup_time, *(efi_bool_t *)arg1, 204 (efi_time_t *)arg2); 205 break; 206 case EFI_GET_VARIABLE: 207 status = efi_call_virt(get_variable, (efi_char16_t *)arg1, 208 (efi_guid_t *)arg2, (u32 *)arg3, 209 (unsigned long *)arg4, (void *)arg5); 210 break; 211 case EFI_GET_NEXT_VARIABLE: 212 status = efi_call_virt(get_next_variable, (unsigned long *)arg1, 213 (efi_char16_t *)arg2, 214 (efi_guid_t *)arg3); 215 break; 216 case EFI_SET_VARIABLE: 217 status = efi_call_virt(set_variable, (efi_char16_t *)arg1, 218 (efi_guid_t *)arg2, *(u32 *)arg3, 219 *(unsigned long *)arg4, (void *)arg5); 220 break; 221 case EFI_QUERY_VARIABLE_INFO: 222 status = efi_call_virt(query_variable_info, *(u32 *)arg1, 223 (u64 *)arg2, (u64 *)arg3, (u64 *)arg4); 224 break; 225 case EFI_GET_NEXT_HIGH_MONO_COUNT: 226 status = efi_call_virt(get_next_high_mono_count, (u32 *)arg1); 227 break; 228 case EFI_UPDATE_CAPSULE: 229 status = efi_call_virt(update_capsule, 230 (efi_capsule_header_t **)arg1, 231 *(unsigned long *)arg2, 232 *(unsigned long *)arg3); 233 break; 234 case EFI_QUERY_CAPSULE_CAPS: 235 status = efi_call_virt(query_capsule_caps, 236 (efi_capsule_header_t **)arg1, 237 *(unsigned long *)arg2, (u64 *)arg3, 238 (int *)arg4); 239 break; 240 default: 241 /* 242 * Ideally, we should never reach here because a caller of this 243 * function should have put the right efi_runtime_service() 244 * function identifier into efi_rts_work->efi_rts_id 245 */ 246 pr_err("Requested executing invalid EFI Runtime Service.\n"); 247 } 248 efi_rts_work.status = status; 249 complete(&efi_rts_work.efi_rts_comp); 250 } 251 252 static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc) 253 { 254 efi_status_t status; 255 256 if (down_interruptible(&efi_runtime_lock)) 257 return EFI_ABORTED; 258 status = efi_queue_work(EFI_GET_TIME, tm, tc, NULL, NULL, NULL); 259 up(&efi_runtime_lock); 260 return status; 261 } 262 263 static efi_status_t virt_efi_set_time(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(EFI_SET_TIME, tm, NULL, NULL, NULL, NULL); 270 up(&efi_runtime_lock); 271 return status; 272 } 273 274 static efi_status_t virt_efi_get_wakeup_time(efi_bool_t *enabled, 275 efi_bool_t *pending, 276 efi_time_t *tm) 277 { 278 efi_status_t status; 279 280 if (down_interruptible(&efi_runtime_lock)) 281 return EFI_ABORTED; 282 status = efi_queue_work(EFI_GET_WAKEUP_TIME, enabled, pending, tm, NULL, 283 NULL); 284 up(&efi_runtime_lock); 285 return status; 286 } 287 288 static efi_status_t virt_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm) 289 { 290 efi_status_t status; 291 292 if (down_interruptible(&efi_runtime_lock)) 293 return EFI_ABORTED; 294 status = efi_queue_work(EFI_SET_WAKEUP_TIME, &enabled, tm, NULL, NULL, 295 NULL); 296 up(&efi_runtime_lock); 297 return status; 298 } 299 300 static efi_status_t virt_efi_get_variable(efi_char16_t *name, 301 efi_guid_t *vendor, 302 u32 *attr, 303 unsigned long *data_size, 304 void *data) 305 { 306 efi_status_t status; 307 308 if (down_interruptible(&efi_runtime_lock)) 309 return EFI_ABORTED; 310 status = efi_queue_work(EFI_GET_VARIABLE, name, vendor, attr, data_size, 311 data); 312 up(&efi_runtime_lock); 313 return status; 314 } 315 316 static efi_status_t virt_efi_get_next_variable(unsigned long *name_size, 317 efi_char16_t *name, 318 efi_guid_t *vendor) 319 { 320 efi_status_t status; 321 322 if (down_interruptible(&efi_runtime_lock)) 323 return EFI_ABORTED; 324 status = efi_queue_work(EFI_GET_NEXT_VARIABLE, name_size, name, vendor, 325 NULL, NULL); 326 up(&efi_runtime_lock); 327 return status; 328 } 329 330 static efi_status_t virt_efi_set_variable(efi_char16_t *name, 331 efi_guid_t *vendor, 332 u32 attr, 333 unsigned long data_size, 334 void *data) 335 { 336 efi_status_t status; 337 338 if (down_interruptible(&efi_runtime_lock)) 339 return EFI_ABORTED; 340 status = efi_queue_work(EFI_SET_VARIABLE, name, vendor, &attr, &data_size, 341 data); 342 up(&efi_runtime_lock); 343 return status; 344 } 345 346 static efi_status_t 347 virt_efi_set_variable_nonblocking(efi_char16_t *name, efi_guid_t *vendor, 348 u32 attr, unsigned long data_size, 349 void *data) 350 { 351 efi_status_t status; 352 353 if (down_trylock(&efi_runtime_lock)) 354 return EFI_NOT_READY; 355 356 status = efi_call_virt(set_variable, name, vendor, attr, data_size, 357 data); 358 up(&efi_runtime_lock); 359 return status; 360 } 361 362 363 static efi_status_t virt_efi_query_variable_info(u32 attr, 364 u64 *storage_space, 365 u64 *remaining_space, 366 u64 *max_variable_size) 367 { 368 efi_status_t status; 369 370 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) 371 return EFI_UNSUPPORTED; 372 373 if (down_interruptible(&efi_runtime_lock)) 374 return EFI_ABORTED; 375 status = efi_queue_work(EFI_QUERY_VARIABLE_INFO, &attr, storage_space, 376 remaining_space, max_variable_size, NULL); 377 up(&efi_runtime_lock); 378 return status; 379 } 380 381 static efi_status_t 382 virt_efi_query_variable_info_nonblocking(u32 attr, 383 u64 *storage_space, 384 u64 *remaining_space, 385 u64 *max_variable_size) 386 { 387 efi_status_t status; 388 389 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) 390 return EFI_UNSUPPORTED; 391 392 if (down_trylock(&efi_runtime_lock)) 393 return EFI_NOT_READY; 394 395 status = efi_call_virt(query_variable_info, attr, storage_space, 396 remaining_space, max_variable_size); 397 up(&efi_runtime_lock); 398 return status; 399 } 400 401 static efi_status_t virt_efi_get_next_high_mono_count(u32 *count) 402 { 403 efi_status_t status; 404 405 if (down_interruptible(&efi_runtime_lock)) 406 return EFI_ABORTED; 407 status = efi_queue_work(EFI_GET_NEXT_HIGH_MONO_COUNT, count, NULL, NULL, 408 NULL, NULL); 409 up(&efi_runtime_lock); 410 return status; 411 } 412 413 static void virt_efi_reset_system(int reset_type, 414 efi_status_t status, 415 unsigned long data_size, 416 efi_char16_t *data) 417 { 418 if (down_trylock(&efi_runtime_lock)) { 419 pr_warn("failed to invoke the reset_system() runtime service:\n" 420 "could not get exclusive access to the firmware\n"); 421 return; 422 } 423 efi_rts_work.efi_rts_id = EFI_RESET_SYSTEM; 424 __efi_call_virt(reset_system, reset_type, status, data_size, data); 425 up(&efi_runtime_lock); 426 } 427 428 static efi_status_t virt_efi_update_capsule(efi_capsule_header_t **capsules, 429 unsigned long count, 430 unsigned long sg_list) 431 { 432 efi_status_t status; 433 434 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) 435 return EFI_UNSUPPORTED; 436 437 if (down_interruptible(&efi_runtime_lock)) 438 return EFI_ABORTED; 439 status = efi_queue_work(EFI_UPDATE_CAPSULE, capsules, &count, &sg_list, 440 NULL, NULL); 441 up(&efi_runtime_lock); 442 return status; 443 } 444 445 static efi_status_t virt_efi_query_capsule_caps(efi_capsule_header_t **capsules, 446 unsigned long count, 447 u64 *max_size, 448 int *reset_type) 449 { 450 efi_status_t status; 451 452 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) 453 return EFI_UNSUPPORTED; 454 455 if (down_interruptible(&efi_runtime_lock)) 456 return EFI_ABORTED; 457 status = efi_queue_work(EFI_QUERY_CAPSULE_CAPS, capsules, &count, 458 max_size, reset_type, NULL); 459 up(&efi_runtime_lock); 460 return status; 461 } 462 463 void efi_native_runtime_setup(void) 464 { 465 efi.get_time = virt_efi_get_time; 466 efi.set_time = virt_efi_set_time; 467 efi.get_wakeup_time = virt_efi_get_wakeup_time; 468 efi.set_wakeup_time = virt_efi_set_wakeup_time; 469 efi.get_variable = virt_efi_get_variable; 470 efi.get_next_variable = virt_efi_get_next_variable; 471 efi.set_variable = virt_efi_set_variable; 472 efi.set_variable_nonblocking = virt_efi_set_variable_nonblocking; 473 efi.get_next_high_mono_count = virt_efi_get_next_high_mono_count; 474 efi.reset_system = virt_efi_reset_system; 475 efi.query_variable_info = virt_efi_query_variable_info; 476 efi.query_variable_info_nonblocking = virt_efi_query_variable_info_nonblocking; 477 efi.update_capsule = virt_efi_update_capsule; 478 efi.query_capsule_caps = virt_efi_query_capsule_caps; 479 } 480