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
efi_call_virt_save_flags(void)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
efi_call_virt_check_flags(unsigned long flags,const char * call)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);
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 */
efi_call_rts(struct work_struct * work)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
virt_efi_get_time(efi_time_t * tm,efi_time_cap_t * tc)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
virt_efi_set_time(efi_time_t * tm)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
virt_efi_get_wakeup_time(efi_bool_t * enabled,efi_bool_t * pending,efi_time_t * tm)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
virt_efi_set_wakeup_time(efi_bool_t enabled,efi_time_t * tm)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
virt_efi_get_variable(efi_char16_t * name,efi_guid_t * vendor,u32 * attr,unsigned long * data_size,void * data)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
virt_efi_get_next_variable(unsigned long * name_size,efi_char16_t * name,efi_guid_t * vendor)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
virt_efi_set_variable(efi_char16_t * name,efi_guid_t * vendor,u32 attr,unsigned long data_size,void * data)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
virt_efi_set_variable_nonblocking(efi_char16_t * name,efi_guid_t * vendor,u32 attr,unsigned long data_size,void * data)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
virt_efi_query_variable_info(u32 attr,u64 * storage_space,u64 * remaining_space,u64 * max_variable_size)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
virt_efi_query_variable_info_nonblocking(u32 attr,u64 * storage_space,u64 * remaining_space,u64 * max_variable_size)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
virt_efi_get_next_high_mono_count(u32 * count)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
virt_efi_reset_system(int reset_type,efi_status_t status,unsigned long data_size,efi_char16_t * data)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
virt_efi_update_capsule(efi_capsule_header_t ** capsules,unsigned long count,unsigned long sg_list)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
virt_efi_query_capsule_caps(efi_capsule_header_t ** capsules,unsigned long count,u64 * max_size,int * reset_type)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
efi_native_runtime_setup(void)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