1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 *
4 * Procedures for interfacing to the RTAS on CHRP machines.
5 *
6 * Peter Bergner, IBM March 2001.
7 * Copyright (C) 2001 IBM.
8 */
9
10 #define pr_fmt(fmt) "rtas: " fmt
11
12 #include <linux/bsearch.h>
13 #include <linux/capability.h>
14 #include <linux/delay.h>
15 #include <linux/export.h>
16 #include <linux/init.h>
17 #include <linux/kconfig.h>
18 #include <linux/kernel.h>
19 #include <linux/lockdep.h>
20 #include <linux/memblock.h>
21 #include <linux/of.h>
22 #include <linux/of_fdt.h>
23 #include <linux/reboot.h>
24 #include <linux/sched.h>
25 #include <linux/security.h>
26 #include <linux/slab.h>
27 #include <linux/spinlock.h>
28 #include <linux/stdarg.h>
29 #include <linux/syscalls.h>
30 #include <linux/types.h>
31 #include <linux/uaccess.h>
32 #include <linux/xarray.h>
33
34 #include <asm/delay.h>
35 #include <asm/firmware.h>
36 #include <asm/interrupt.h>
37 #include <asm/machdep.h>
38 #include <asm/mmu.h>
39 #include <asm/page.h>
40 #include <asm/rtas-work-area.h>
41 #include <asm/rtas.h>
42 #include <asm/time.h>
43 #include <asm/trace.h>
44 #include <asm/udbg.h>
45
46 struct rtas_filter {
47 /* Indexes into the args buffer, -1 if not used */
48 const int buf_idx1;
49 const int size_idx1;
50 const int buf_idx2;
51 const int size_idx2;
52 /*
53 * Assumed buffer size per the spec if the function does not
54 * have a size parameter, e.g. ibm,errinjct. 0 if unused.
55 */
56 const int fixed_size;
57 };
58
59 /**
60 * struct rtas_function - Descriptor for RTAS functions.
61 *
62 * @token: Value of @name if it exists under the /rtas node.
63 * @name: Function name.
64 * @filter: If non-NULL, invoking this function via the rtas syscall is
65 * generally allowed, and @filter describes constraints on the
66 * arguments. See also @banned_for_syscall_on_le.
67 * @banned_for_syscall_on_le: Set when call via sys_rtas is generally allowed
68 * but specifically restricted on ppc64le. Such
69 * functions are believed to have no users on
70 * ppc64le, and we want to keep it that way. It does
71 * not make sense for this to be set when @filter
72 * is NULL.
73 */
74 struct rtas_function {
75 s32 token;
76 const bool banned_for_syscall_on_le:1;
77 const char * const name;
78 const struct rtas_filter *filter;
79 };
80
81 static struct rtas_function rtas_function_table[] __ro_after_init = {
82 [RTAS_FNIDX__CHECK_EXCEPTION] = {
83 .name = "check-exception",
84 },
85 [RTAS_FNIDX__DISPLAY_CHARACTER] = {
86 .name = "display-character",
87 .filter = &(const struct rtas_filter) {
88 .buf_idx1 = -1, .size_idx1 = -1,
89 .buf_idx2 = -1, .size_idx2 = -1,
90 },
91 },
92 [RTAS_FNIDX__EVENT_SCAN] = {
93 .name = "event-scan",
94 },
95 [RTAS_FNIDX__FREEZE_TIME_BASE] = {
96 .name = "freeze-time-base",
97 },
98 [RTAS_FNIDX__GET_POWER_LEVEL] = {
99 .name = "get-power-level",
100 .filter = &(const struct rtas_filter) {
101 .buf_idx1 = -1, .size_idx1 = -1,
102 .buf_idx2 = -1, .size_idx2 = -1,
103 },
104 },
105 [RTAS_FNIDX__GET_SENSOR_STATE] = {
106 .name = "get-sensor-state",
107 .filter = &(const struct rtas_filter) {
108 .buf_idx1 = -1, .size_idx1 = -1,
109 .buf_idx2 = -1, .size_idx2 = -1,
110 },
111 },
112 [RTAS_FNIDX__GET_TERM_CHAR] = {
113 .name = "get-term-char",
114 },
115 [RTAS_FNIDX__GET_TIME_OF_DAY] = {
116 .name = "get-time-of-day",
117 .filter = &(const struct rtas_filter) {
118 .buf_idx1 = -1, .size_idx1 = -1,
119 .buf_idx2 = -1, .size_idx2 = -1,
120 },
121 },
122 [RTAS_FNIDX__IBM_ACTIVATE_FIRMWARE] = {
123 .name = "ibm,activate-firmware",
124 .filter = &(const struct rtas_filter) {
125 .buf_idx1 = -1, .size_idx1 = -1,
126 .buf_idx2 = -1, .size_idx2 = -1,
127 },
128 },
129 [RTAS_FNIDX__IBM_CBE_START_PTCAL] = {
130 .name = "ibm,cbe-start-ptcal",
131 },
132 [RTAS_FNIDX__IBM_CBE_STOP_PTCAL] = {
133 .name = "ibm,cbe-stop-ptcal",
134 },
135 [RTAS_FNIDX__IBM_CHANGE_MSI] = {
136 .name = "ibm,change-msi",
137 },
138 [RTAS_FNIDX__IBM_CLOSE_ERRINJCT] = {
139 .name = "ibm,close-errinjct",
140 .filter = &(const struct rtas_filter) {
141 .buf_idx1 = -1, .size_idx1 = -1,
142 .buf_idx2 = -1, .size_idx2 = -1,
143 },
144 },
145 [RTAS_FNIDX__IBM_CONFIGURE_BRIDGE] = {
146 .name = "ibm,configure-bridge",
147 },
148 [RTAS_FNIDX__IBM_CONFIGURE_CONNECTOR] = {
149 .name = "ibm,configure-connector",
150 .filter = &(const struct rtas_filter) {
151 .buf_idx1 = 0, .size_idx1 = -1,
152 .buf_idx2 = 1, .size_idx2 = -1,
153 .fixed_size = 4096,
154 },
155 },
156 [RTAS_FNIDX__IBM_CONFIGURE_KERNEL_DUMP] = {
157 .name = "ibm,configure-kernel-dump",
158 },
159 [RTAS_FNIDX__IBM_CONFIGURE_PE] = {
160 .name = "ibm,configure-pe",
161 },
162 [RTAS_FNIDX__IBM_CREATE_PE_DMA_WINDOW] = {
163 .name = "ibm,create-pe-dma-window",
164 },
165 [RTAS_FNIDX__IBM_DISPLAY_MESSAGE] = {
166 .name = "ibm,display-message",
167 .filter = &(const struct rtas_filter) {
168 .buf_idx1 = 0, .size_idx1 = -1,
169 .buf_idx2 = -1, .size_idx2 = -1,
170 },
171 },
172 [RTAS_FNIDX__IBM_ERRINJCT] = {
173 .name = "ibm,errinjct",
174 .filter = &(const struct rtas_filter) {
175 .buf_idx1 = 2, .size_idx1 = -1,
176 .buf_idx2 = -1, .size_idx2 = -1,
177 .fixed_size = 1024,
178 },
179 },
180 [RTAS_FNIDX__IBM_EXTI2C] = {
181 .name = "ibm,exti2c",
182 },
183 [RTAS_FNIDX__IBM_GET_CONFIG_ADDR_INFO] = {
184 .name = "ibm,get-config-addr-info",
185 },
186 [RTAS_FNIDX__IBM_GET_CONFIG_ADDR_INFO2] = {
187 .name = "ibm,get-config-addr-info2",
188 .filter = &(const struct rtas_filter) {
189 .buf_idx1 = -1, .size_idx1 = -1,
190 .buf_idx2 = -1, .size_idx2 = -1,
191 },
192 },
193 [RTAS_FNIDX__IBM_GET_DYNAMIC_SENSOR_STATE] = {
194 .name = "ibm,get-dynamic-sensor-state",
195 .filter = &(const struct rtas_filter) {
196 .buf_idx1 = 1, .size_idx1 = -1,
197 .buf_idx2 = -1, .size_idx2 = -1,
198 },
199 },
200 [RTAS_FNIDX__IBM_GET_INDICES] = {
201 .name = "ibm,get-indices",
202 .filter = &(const struct rtas_filter) {
203 .buf_idx1 = 2, .size_idx1 = 3,
204 .buf_idx2 = -1, .size_idx2 = -1,
205 },
206 },
207 [RTAS_FNIDX__IBM_GET_RIO_TOPOLOGY] = {
208 .name = "ibm,get-rio-topology",
209 },
210 [RTAS_FNIDX__IBM_GET_SYSTEM_PARAMETER] = {
211 .name = "ibm,get-system-parameter",
212 .filter = &(const struct rtas_filter) {
213 .buf_idx1 = 1, .size_idx1 = 2,
214 .buf_idx2 = -1, .size_idx2 = -1,
215 },
216 },
217 [RTAS_FNIDX__IBM_GET_VPD] = {
218 .name = "ibm,get-vpd",
219 .filter = &(const struct rtas_filter) {
220 .buf_idx1 = 0, .size_idx1 = -1,
221 .buf_idx2 = 1, .size_idx2 = 2,
222 },
223 },
224 [RTAS_FNIDX__IBM_GET_XIVE] = {
225 .name = "ibm,get-xive",
226 },
227 [RTAS_FNIDX__IBM_INT_OFF] = {
228 .name = "ibm,int-off",
229 },
230 [RTAS_FNIDX__IBM_INT_ON] = {
231 .name = "ibm,int-on",
232 },
233 [RTAS_FNIDX__IBM_IO_QUIESCE_ACK] = {
234 .name = "ibm,io-quiesce-ack",
235 },
236 [RTAS_FNIDX__IBM_LPAR_PERFTOOLS] = {
237 .name = "ibm,lpar-perftools",
238 .filter = &(const struct rtas_filter) {
239 .buf_idx1 = 2, .size_idx1 = 3,
240 .buf_idx2 = -1, .size_idx2 = -1,
241 },
242 },
243 [RTAS_FNIDX__IBM_MANAGE_FLASH_IMAGE] = {
244 .name = "ibm,manage-flash-image",
245 },
246 [RTAS_FNIDX__IBM_MANAGE_STORAGE_PRESERVATION] = {
247 .name = "ibm,manage-storage-preservation",
248 },
249 [RTAS_FNIDX__IBM_NMI_INTERLOCK] = {
250 .name = "ibm,nmi-interlock",
251 },
252 [RTAS_FNIDX__IBM_NMI_REGISTER] = {
253 .name = "ibm,nmi-register",
254 },
255 [RTAS_FNIDX__IBM_OPEN_ERRINJCT] = {
256 .name = "ibm,open-errinjct",
257 .filter = &(const struct rtas_filter) {
258 .buf_idx1 = -1, .size_idx1 = -1,
259 .buf_idx2 = -1, .size_idx2 = -1,
260 },
261 },
262 [RTAS_FNIDX__IBM_OPEN_SRIOV_ALLOW_UNFREEZE] = {
263 .name = "ibm,open-sriov-allow-unfreeze",
264 },
265 [RTAS_FNIDX__IBM_OPEN_SRIOV_MAP_PE_NUMBER] = {
266 .name = "ibm,open-sriov-map-pe-number",
267 },
268 [RTAS_FNIDX__IBM_OS_TERM] = {
269 .name = "ibm,os-term",
270 },
271 [RTAS_FNIDX__IBM_PARTNER_CONTROL] = {
272 .name = "ibm,partner-control",
273 },
274 [RTAS_FNIDX__IBM_PHYSICAL_ATTESTATION] = {
275 .name = "ibm,physical-attestation",
276 .filter = &(const struct rtas_filter) {
277 .buf_idx1 = 0, .size_idx1 = 1,
278 .buf_idx2 = -1, .size_idx2 = -1,
279 },
280 },
281 [RTAS_FNIDX__IBM_PLATFORM_DUMP] = {
282 .name = "ibm,platform-dump",
283 .filter = &(const struct rtas_filter) {
284 .buf_idx1 = 4, .size_idx1 = 5,
285 .buf_idx2 = -1, .size_idx2 = -1,
286 },
287 },
288 [RTAS_FNIDX__IBM_POWER_OFF_UPS] = {
289 .name = "ibm,power-off-ups",
290 },
291 [RTAS_FNIDX__IBM_QUERY_INTERRUPT_SOURCE_NUMBER] = {
292 .name = "ibm,query-interrupt-source-number",
293 },
294 [RTAS_FNIDX__IBM_QUERY_PE_DMA_WINDOW] = {
295 .name = "ibm,query-pe-dma-window",
296 },
297 [RTAS_FNIDX__IBM_READ_PCI_CONFIG] = {
298 .name = "ibm,read-pci-config",
299 },
300 [RTAS_FNIDX__IBM_READ_SLOT_RESET_STATE] = {
301 .name = "ibm,read-slot-reset-state",
302 .filter = &(const struct rtas_filter) {
303 .buf_idx1 = -1, .size_idx1 = -1,
304 .buf_idx2 = -1, .size_idx2 = -1,
305 },
306 },
307 [RTAS_FNIDX__IBM_READ_SLOT_RESET_STATE2] = {
308 .name = "ibm,read-slot-reset-state2",
309 },
310 [RTAS_FNIDX__IBM_REMOVE_PE_DMA_WINDOW] = {
311 .name = "ibm,remove-pe-dma-window",
312 },
313 [RTAS_FNIDX__IBM_RESET_PE_DMA_WINDOW] = {
314 /*
315 * Note: PAPR+ v2.13 7.3.31.4.1 spells this as
316 * "ibm,reset-pe-dma-windows" (plural), but RTAS
317 * implementations use the singular form in practice.
318 */
319 .name = "ibm,reset-pe-dma-window",
320 },
321 [RTAS_FNIDX__IBM_SCAN_LOG_DUMP] = {
322 .name = "ibm,scan-log-dump",
323 .filter = &(const struct rtas_filter) {
324 .buf_idx1 = 0, .size_idx1 = 1,
325 .buf_idx2 = -1, .size_idx2 = -1,
326 },
327 },
328 [RTAS_FNIDX__IBM_SET_DYNAMIC_INDICATOR] = {
329 .name = "ibm,set-dynamic-indicator",
330 .filter = &(const struct rtas_filter) {
331 .buf_idx1 = 2, .size_idx1 = -1,
332 .buf_idx2 = -1, .size_idx2 = -1,
333 },
334 },
335 [RTAS_FNIDX__IBM_SET_EEH_OPTION] = {
336 .name = "ibm,set-eeh-option",
337 .filter = &(const struct rtas_filter) {
338 .buf_idx1 = -1, .size_idx1 = -1,
339 .buf_idx2 = -1, .size_idx2 = -1,
340 },
341 },
342 [RTAS_FNIDX__IBM_SET_SLOT_RESET] = {
343 .name = "ibm,set-slot-reset",
344 },
345 [RTAS_FNIDX__IBM_SET_SYSTEM_PARAMETER] = {
346 .name = "ibm,set-system-parameter",
347 .filter = &(const struct rtas_filter) {
348 .buf_idx1 = 1, .size_idx1 = -1,
349 .buf_idx2 = -1, .size_idx2 = -1,
350 },
351 },
352 [RTAS_FNIDX__IBM_SET_XIVE] = {
353 .name = "ibm,set-xive",
354 },
355 [RTAS_FNIDX__IBM_SLOT_ERROR_DETAIL] = {
356 .name = "ibm,slot-error-detail",
357 },
358 [RTAS_FNIDX__IBM_SUSPEND_ME] = {
359 .name = "ibm,suspend-me",
360 .banned_for_syscall_on_le = true,
361 .filter = &(const struct rtas_filter) {
362 .buf_idx1 = -1, .size_idx1 = -1,
363 .buf_idx2 = -1, .size_idx2 = -1,
364 },
365 },
366 [RTAS_FNIDX__IBM_TUNE_DMA_PARMS] = {
367 .name = "ibm,tune-dma-parms",
368 },
369 [RTAS_FNIDX__IBM_UPDATE_FLASH_64_AND_REBOOT] = {
370 .name = "ibm,update-flash-64-and-reboot",
371 },
372 [RTAS_FNIDX__IBM_UPDATE_NODES] = {
373 .name = "ibm,update-nodes",
374 .banned_for_syscall_on_le = true,
375 .filter = &(const struct rtas_filter) {
376 .buf_idx1 = 0, .size_idx1 = -1,
377 .buf_idx2 = -1, .size_idx2 = -1,
378 .fixed_size = 4096,
379 },
380 },
381 [RTAS_FNIDX__IBM_UPDATE_PROPERTIES] = {
382 .name = "ibm,update-properties",
383 .banned_for_syscall_on_le = true,
384 .filter = &(const struct rtas_filter) {
385 .buf_idx1 = 0, .size_idx1 = -1,
386 .buf_idx2 = -1, .size_idx2 = -1,
387 .fixed_size = 4096,
388 },
389 },
390 [RTAS_FNIDX__IBM_VALIDATE_FLASH_IMAGE] = {
391 .name = "ibm,validate-flash-image",
392 },
393 [RTAS_FNIDX__IBM_WRITE_PCI_CONFIG] = {
394 .name = "ibm,write-pci-config",
395 },
396 [RTAS_FNIDX__NVRAM_FETCH] = {
397 .name = "nvram-fetch",
398 },
399 [RTAS_FNIDX__NVRAM_STORE] = {
400 .name = "nvram-store",
401 },
402 [RTAS_FNIDX__POWER_OFF] = {
403 .name = "power-off",
404 },
405 [RTAS_FNIDX__PUT_TERM_CHAR] = {
406 .name = "put-term-char",
407 },
408 [RTAS_FNIDX__QUERY_CPU_STOPPED_STATE] = {
409 .name = "query-cpu-stopped-state",
410 },
411 [RTAS_FNIDX__READ_PCI_CONFIG] = {
412 .name = "read-pci-config",
413 },
414 [RTAS_FNIDX__RTAS_LAST_ERROR] = {
415 .name = "rtas-last-error",
416 },
417 [RTAS_FNIDX__SET_INDICATOR] = {
418 .name = "set-indicator",
419 .filter = &(const struct rtas_filter) {
420 .buf_idx1 = -1, .size_idx1 = -1,
421 .buf_idx2 = -1, .size_idx2 = -1,
422 },
423 },
424 [RTAS_FNIDX__SET_POWER_LEVEL] = {
425 .name = "set-power-level",
426 .filter = &(const struct rtas_filter) {
427 .buf_idx1 = -1, .size_idx1 = -1,
428 .buf_idx2 = -1, .size_idx2 = -1,
429 },
430 },
431 [RTAS_FNIDX__SET_TIME_FOR_POWER_ON] = {
432 .name = "set-time-for-power-on",
433 .filter = &(const struct rtas_filter) {
434 .buf_idx1 = -1, .size_idx1 = -1,
435 .buf_idx2 = -1, .size_idx2 = -1,
436 },
437 },
438 [RTAS_FNIDX__SET_TIME_OF_DAY] = {
439 .name = "set-time-of-day",
440 .filter = &(const struct rtas_filter) {
441 .buf_idx1 = -1, .size_idx1 = -1,
442 .buf_idx2 = -1, .size_idx2 = -1,
443 },
444 },
445 [RTAS_FNIDX__START_CPU] = {
446 .name = "start-cpu",
447 },
448 [RTAS_FNIDX__STOP_SELF] = {
449 .name = "stop-self",
450 },
451 [RTAS_FNIDX__SYSTEM_REBOOT] = {
452 .name = "system-reboot",
453 },
454 [RTAS_FNIDX__THAW_TIME_BASE] = {
455 .name = "thaw-time-base",
456 },
457 [RTAS_FNIDX__WRITE_PCI_CONFIG] = {
458 .name = "write-pci-config",
459 },
460 };
461
462 /*
463 * Nearly all RTAS calls need to be serialized. All uses of the
464 * default rtas_args block must hold rtas_lock.
465 *
466 * Exceptions to the RTAS serialization requirement (e.g. stop-self)
467 * must use a separate rtas_args structure.
468 */
469 static DEFINE_RAW_SPINLOCK(rtas_lock);
470 static struct rtas_args rtas_args;
471
472 /**
473 * rtas_function_token() - RTAS function token lookup.
474 * @handle: Function handle, e.g. RTAS_FN_EVENT_SCAN.
475 *
476 * Context: Any context.
477 * Return: the token value for the function if implemented by this platform,
478 * otherwise RTAS_UNKNOWN_SERVICE.
479 */
rtas_function_token(const rtas_fn_handle_t handle)480 s32 rtas_function_token(const rtas_fn_handle_t handle)
481 {
482 const size_t index = handle.index;
483 const bool out_of_bounds = index >= ARRAY_SIZE(rtas_function_table);
484
485 if (WARN_ONCE(out_of_bounds, "invalid function index %zu", index))
486 return RTAS_UNKNOWN_SERVICE;
487 /*
488 * Various drivers attempt token lookups on non-RTAS
489 * platforms.
490 */
491 if (!rtas.dev)
492 return RTAS_UNKNOWN_SERVICE;
493
494 return rtas_function_table[index].token;
495 }
496 EXPORT_SYMBOL_GPL(rtas_function_token);
497
rtas_function_cmp(const void * a,const void * b)498 static int rtas_function_cmp(const void *a, const void *b)
499 {
500 const struct rtas_function *f1 = a;
501 const struct rtas_function *f2 = b;
502
503 return strcmp(f1->name, f2->name);
504 }
505
506 /*
507 * Boot-time initialization of the function table needs the lookup to
508 * return a non-const-qualified object. Use rtas_name_to_function()
509 * in all other contexts.
510 */
__rtas_name_to_function(const char * name)511 static struct rtas_function *__rtas_name_to_function(const char *name)
512 {
513 const struct rtas_function key = {
514 .name = name,
515 };
516 struct rtas_function *found;
517
518 found = bsearch(&key, rtas_function_table, ARRAY_SIZE(rtas_function_table),
519 sizeof(rtas_function_table[0]), rtas_function_cmp);
520
521 return found;
522 }
523
rtas_name_to_function(const char * name)524 static const struct rtas_function *rtas_name_to_function(const char *name)
525 {
526 return __rtas_name_to_function(name);
527 }
528
529 static DEFINE_XARRAY(rtas_token_to_function_xarray);
530
rtas_token_to_function_xarray_init(void)531 static int __init rtas_token_to_function_xarray_init(void)
532 {
533 int err = 0;
534
535 for (size_t i = 0; i < ARRAY_SIZE(rtas_function_table); ++i) {
536 const struct rtas_function *func = &rtas_function_table[i];
537 const s32 token = func->token;
538
539 if (token == RTAS_UNKNOWN_SERVICE)
540 continue;
541
542 err = xa_err(xa_store(&rtas_token_to_function_xarray,
543 token, (void *)func, GFP_KERNEL));
544 if (err)
545 break;
546 }
547
548 return err;
549 }
550 arch_initcall(rtas_token_to_function_xarray_init);
551
552 /*
553 * For use by sys_rtas(), where the token value is provided by user
554 * space and we don't want to warn on failed lookups.
555 */
rtas_token_to_function_untrusted(s32 token)556 static const struct rtas_function *rtas_token_to_function_untrusted(s32 token)
557 {
558 return xa_load(&rtas_token_to_function_xarray, token);
559 }
560
561 /*
562 * Reverse lookup for deriving the function descriptor from a
563 * known-good token value in contexts where the former is not already
564 * available. @token must be valid, e.g. derived from the result of a
565 * prior lookup against the function table.
566 */
rtas_token_to_function(s32 token)567 static const struct rtas_function *rtas_token_to_function(s32 token)
568 {
569 const struct rtas_function *func;
570
571 if (WARN_ONCE(token < 0, "invalid token %d", token))
572 return NULL;
573
574 func = rtas_token_to_function_untrusted(token);
575
576 if (WARN_ONCE(!func, "unexpected failed lookup for token %d", token))
577 return NULL;
578
579 return func;
580 }
581
582 /* This is here deliberately so it's only used in this file */
583 void enter_rtas(unsigned long);
584
__do_enter_rtas(struct rtas_args * args)585 static void __do_enter_rtas(struct rtas_args *args)
586 {
587 enter_rtas(__pa(args));
588 srr_regs_clobbered(); /* rtas uses SRRs, invalidate */
589 }
590
__do_enter_rtas_trace(struct rtas_args * args)591 static void __do_enter_rtas_trace(struct rtas_args *args)
592 {
593 const char *name = NULL;
594
595 if (args == &rtas_args)
596 lockdep_assert_held(&rtas_lock);
597 /*
598 * If the tracepoints that consume the function name aren't
599 * active, avoid the lookup.
600 */
601 if ((trace_rtas_input_enabled() || trace_rtas_output_enabled())) {
602 const s32 token = be32_to_cpu(args->token);
603 const struct rtas_function *func = rtas_token_to_function(token);
604
605 name = func->name;
606 }
607
608 trace_rtas_input(args, name);
609 trace_rtas_ll_entry(args);
610
611 __do_enter_rtas(args);
612
613 trace_rtas_ll_exit(args);
614 trace_rtas_output(args, name);
615 }
616
do_enter_rtas(struct rtas_args * args)617 static void do_enter_rtas(struct rtas_args *args)
618 {
619 const unsigned long msr = mfmsr();
620 /*
621 * Situations where we want to skip any active tracepoints for
622 * safety reasons:
623 *
624 * 1. The last code executed on an offline CPU as it stops,
625 * i.e. we're about to call stop-self. The tracepoints'
626 * function name lookup uses xarray, which uses RCU, which
627 * isn't valid to call on an offline CPU. Any events
628 * emitted on an offline CPU will be discarded anyway.
629 *
630 * 2. In real mode, as when invoking ibm,nmi-interlock from
631 * the pseries MCE handler. We cannot count on trace
632 * buffers or the entries in rtas_token_to_function_xarray
633 * to be contained in the RMO.
634 */
635 const unsigned long mask = MSR_IR | MSR_DR;
636 const bool can_trace = likely(cpu_online(raw_smp_processor_id()) &&
637 (msr & mask) == mask);
638 /*
639 * Make sure MSR[RI] is currently enabled as it will be forced later
640 * in enter_rtas.
641 */
642 BUG_ON(!(msr & MSR_RI));
643
644 BUG_ON(!irqs_disabled());
645
646 hard_irq_disable(); /* Ensure MSR[EE] is disabled on PPC64 */
647
648 if (can_trace)
649 __do_enter_rtas_trace(args);
650 else
651 __do_enter_rtas(args);
652 }
653
654 struct rtas_t rtas;
655
656 DEFINE_SPINLOCK(rtas_data_buf_lock);
657 EXPORT_SYMBOL_GPL(rtas_data_buf_lock);
658
659 char rtas_data_buf[RTAS_DATA_BUF_SIZE] __aligned(SZ_4K);
660 EXPORT_SYMBOL_GPL(rtas_data_buf);
661
662 unsigned long rtas_rmo_buf;
663
664 /*
665 * If non-NULL, this gets called when the kernel terminates.
666 * This is done like this so rtas_flash can be a module.
667 */
668 void (*rtas_flash_term_hook)(int);
669 EXPORT_SYMBOL_GPL(rtas_flash_term_hook);
670
671 /*
672 * call_rtas_display_status and call_rtas_display_status_delay
673 * are designed only for very early low-level debugging, which
674 * is why the token is hard-coded to 10.
675 */
call_rtas_display_status(unsigned char c)676 static void call_rtas_display_status(unsigned char c)
677 {
678 unsigned long flags;
679
680 if (!rtas.base)
681 return;
682
683 raw_spin_lock_irqsave(&rtas_lock, flags);
684 rtas_call_unlocked(&rtas_args, 10, 1, 1, NULL, c);
685 raw_spin_unlock_irqrestore(&rtas_lock, flags);
686 }
687
call_rtas_display_status_delay(char c)688 static void call_rtas_display_status_delay(char c)
689 {
690 static int pending_newline = 0; /* did last write end with unprinted newline? */
691 static int width = 16;
692
693 if (c == '\n') {
694 while (width-- > 0)
695 call_rtas_display_status(' ');
696 width = 16;
697 mdelay(500);
698 pending_newline = 1;
699 } else {
700 if (pending_newline) {
701 call_rtas_display_status('\r');
702 call_rtas_display_status('\n');
703 }
704 pending_newline = 0;
705 if (width--) {
706 call_rtas_display_status(c);
707 udelay(10000);
708 }
709 }
710 }
711
udbg_init_rtas_panel(void)712 void __init udbg_init_rtas_panel(void)
713 {
714 udbg_putc = call_rtas_display_status_delay;
715 }
716
717 #ifdef CONFIG_UDBG_RTAS_CONSOLE
718
719 /* If you think you're dying before early_init_dt_scan_rtas() does its
720 * work, you can hard code the token values for your firmware here and
721 * hardcode rtas.base/entry etc.
722 */
723 static unsigned int rtas_putchar_token = RTAS_UNKNOWN_SERVICE;
724 static unsigned int rtas_getchar_token = RTAS_UNKNOWN_SERVICE;
725
udbg_rtascon_putc(char c)726 static void udbg_rtascon_putc(char c)
727 {
728 int tries;
729
730 if (!rtas.base)
731 return;
732
733 /* Add CRs before LFs */
734 if (c == '\n')
735 udbg_rtascon_putc('\r');
736
737 /* if there is more than one character to be displayed, wait a bit */
738 for (tries = 0; tries < 16; tries++) {
739 if (rtas_call(rtas_putchar_token, 1, 1, NULL, c) == 0)
740 break;
741 udelay(1000);
742 }
743 }
744
udbg_rtascon_getc_poll(void)745 static int udbg_rtascon_getc_poll(void)
746 {
747 int c;
748
749 if (!rtas.base)
750 return -1;
751
752 if (rtas_call(rtas_getchar_token, 0, 2, &c))
753 return -1;
754
755 return c;
756 }
757
udbg_rtascon_getc(void)758 static int udbg_rtascon_getc(void)
759 {
760 int c;
761
762 while ((c = udbg_rtascon_getc_poll()) == -1)
763 ;
764
765 return c;
766 }
767
768
udbg_init_rtas_console(void)769 void __init udbg_init_rtas_console(void)
770 {
771 udbg_putc = udbg_rtascon_putc;
772 udbg_getc = udbg_rtascon_getc;
773 udbg_getc_poll = udbg_rtascon_getc_poll;
774 }
775 #endif /* CONFIG_UDBG_RTAS_CONSOLE */
776
rtas_progress(char * s,unsigned short hex)777 void rtas_progress(char *s, unsigned short hex)
778 {
779 struct device_node *root;
780 int width;
781 const __be32 *p;
782 char *os;
783 static int display_character, set_indicator;
784 static int display_width, display_lines, form_feed;
785 static const int *row_width;
786 static DEFINE_SPINLOCK(progress_lock);
787 static int current_line;
788 static int pending_newline = 0; /* did last write end with unprinted newline? */
789
790 if (!rtas.base)
791 return;
792
793 if (display_width == 0) {
794 display_width = 0x10;
795 if ((root = of_find_node_by_path("/rtas"))) {
796 if ((p = of_get_property(root,
797 "ibm,display-line-length", NULL)))
798 display_width = be32_to_cpu(*p);
799 if ((p = of_get_property(root,
800 "ibm,form-feed", NULL)))
801 form_feed = be32_to_cpu(*p);
802 if ((p = of_get_property(root,
803 "ibm,display-number-of-lines", NULL)))
804 display_lines = be32_to_cpu(*p);
805 row_width = of_get_property(root,
806 "ibm,display-truncation-length", NULL);
807 of_node_put(root);
808 }
809 display_character = rtas_function_token(RTAS_FN_DISPLAY_CHARACTER);
810 set_indicator = rtas_function_token(RTAS_FN_SET_INDICATOR);
811 }
812
813 if (display_character == RTAS_UNKNOWN_SERVICE) {
814 /* use hex display if available */
815 if (set_indicator != RTAS_UNKNOWN_SERVICE)
816 rtas_call(set_indicator, 3, 1, NULL, 6, 0, hex);
817 return;
818 }
819
820 spin_lock(&progress_lock);
821
822 /*
823 * Last write ended with newline, but we didn't print it since
824 * it would just clear the bottom line of output. Print it now
825 * instead.
826 *
827 * If no newline is pending and form feed is supported, clear the
828 * display with a form feed; otherwise, print a CR to start output
829 * at the beginning of the line.
830 */
831 if (pending_newline) {
832 rtas_call(display_character, 1, 1, NULL, '\r');
833 rtas_call(display_character, 1, 1, NULL, '\n');
834 pending_newline = 0;
835 } else {
836 current_line = 0;
837 if (form_feed)
838 rtas_call(display_character, 1, 1, NULL,
839 (char)form_feed);
840 else
841 rtas_call(display_character, 1, 1, NULL, '\r');
842 }
843
844 if (row_width)
845 width = row_width[current_line];
846 else
847 width = display_width;
848 os = s;
849 while (*os) {
850 if (*os == '\n' || *os == '\r') {
851 /* If newline is the last character, save it
852 * until next call to avoid bumping up the
853 * display output.
854 */
855 if (*os == '\n' && !os[1]) {
856 pending_newline = 1;
857 current_line++;
858 if (current_line > display_lines-1)
859 current_line = display_lines-1;
860 spin_unlock(&progress_lock);
861 return;
862 }
863
864 /* RTAS wants CR-LF, not just LF */
865
866 if (*os == '\n') {
867 rtas_call(display_character, 1, 1, NULL, '\r');
868 rtas_call(display_character, 1, 1, NULL, '\n');
869 } else {
870 /* CR might be used to re-draw a line, so we'll
871 * leave it alone and not add LF.
872 */
873 rtas_call(display_character, 1, 1, NULL, *os);
874 }
875
876 if (row_width)
877 width = row_width[current_line];
878 else
879 width = display_width;
880 } else {
881 width--;
882 rtas_call(display_character, 1, 1, NULL, *os);
883 }
884
885 os++;
886
887 /* if we overwrite the screen length */
888 if (width <= 0)
889 while ((*os != 0) && (*os != '\n') && (*os != '\r'))
890 os++;
891 }
892
893 spin_unlock(&progress_lock);
894 }
895 EXPORT_SYMBOL_GPL(rtas_progress); /* needed by rtas_flash module */
896
rtas_token(const char * service)897 int rtas_token(const char *service)
898 {
899 const struct rtas_function *func;
900 const __be32 *tokp;
901
902 if (rtas.dev == NULL)
903 return RTAS_UNKNOWN_SERVICE;
904
905 func = rtas_name_to_function(service);
906 if (func)
907 return func->token;
908 /*
909 * The caller is looking up a name that is not known to be an
910 * RTAS function. Either it's a function that needs to be
911 * added to the table, or they're misusing rtas_token() to
912 * access non-function properties of the /rtas node. Warn and
913 * fall back to the legacy behavior.
914 */
915 WARN_ONCE(1, "unknown function `%s`, should it be added to rtas_function_table?\n",
916 service);
917
918 tokp = of_get_property(rtas.dev, service, NULL);
919 return tokp ? be32_to_cpu(*tokp) : RTAS_UNKNOWN_SERVICE;
920 }
921 EXPORT_SYMBOL_GPL(rtas_token);
922
rtas_service_present(const char * service)923 int rtas_service_present(const char *service)
924 {
925 return rtas_token(service) != RTAS_UNKNOWN_SERVICE;
926 }
927
928 #ifdef CONFIG_RTAS_ERROR_LOGGING
929
930 static u32 rtas_error_log_max __ro_after_init = RTAS_ERROR_LOG_MAX;
931
932 /*
933 * Return the firmware-specified size of the error log buffer
934 * for all rtas calls that require an error buffer argument.
935 * This includes 'check-exception' and 'rtas-last-error'.
936 */
rtas_get_error_log_max(void)937 int rtas_get_error_log_max(void)
938 {
939 return rtas_error_log_max;
940 }
941
init_error_log_max(void)942 static void __init init_error_log_max(void)
943 {
944 static const char propname[] __initconst = "rtas-error-log-max";
945 u32 max;
946
947 if (of_property_read_u32(rtas.dev, propname, &max)) {
948 pr_warn("%s not found, using default of %u\n",
949 propname, RTAS_ERROR_LOG_MAX);
950 max = RTAS_ERROR_LOG_MAX;
951 }
952
953 if (max > RTAS_ERROR_LOG_MAX) {
954 pr_warn("%s = %u, clamping max error log size to %u\n",
955 propname, max, RTAS_ERROR_LOG_MAX);
956 max = RTAS_ERROR_LOG_MAX;
957 }
958
959 rtas_error_log_max = max;
960 }
961
962
963 static char rtas_err_buf[RTAS_ERROR_LOG_MAX];
964
965 /** Return a copy of the detailed error text associated with the
966 * most recent failed call to rtas. Because the error text
967 * might go stale if there are any other intervening rtas calls,
968 * this routine must be called atomically with whatever produced
969 * the error (i.e. with rtas_lock still held from the previous call).
970 */
__fetch_rtas_last_error(char * altbuf)971 static char *__fetch_rtas_last_error(char *altbuf)
972 {
973 const s32 token = rtas_function_token(RTAS_FN_RTAS_LAST_ERROR);
974 struct rtas_args err_args, save_args;
975 u32 bufsz;
976 char *buf = NULL;
977
978 lockdep_assert_held(&rtas_lock);
979
980 if (token == -1)
981 return NULL;
982
983 bufsz = rtas_get_error_log_max();
984
985 err_args.token = cpu_to_be32(token);
986 err_args.nargs = cpu_to_be32(2);
987 err_args.nret = cpu_to_be32(1);
988 err_args.args[0] = cpu_to_be32(__pa(rtas_err_buf));
989 err_args.args[1] = cpu_to_be32(bufsz);
990 err_args.args[2] = 0;
991
992 save_args = rtas_args;
993 rtas_args = err_args;
994
995 do_enter_rtas(&rtas_args);
996
997 err_args = rtas_args;
998 rtas_args = save_args;
999
1000 /* Log the error in the unlikely case that there was one. */
1001 if (unlikely(err_args.args[2] == 0)) {
1002 if (altbuf) {
1003 buf = altbuf;
1004 } else {
1005 buf = rtas_err_buf;
1006 if (slab_is_available())
1007 buf = kmalloc(RTAS_ERROR_LOG_MAX, GFP_ATOMIC);
1008 }
1009 if (buf)
1010 memmove(buf, rtas_err_buf, RTAS_ERROR_LOG_MAX);
1011 }
1012
1013 return buf;
1014 }
1015
1016 #define get_errorlog_buffer() kmalloc(RTAS_ERROR_LOG_MAX, GFP_KERNEL)
1017
1018 #else /* CONFIG_RTAS_ERROR_LOGGING */
1019 #define __fetch_rtas_last_error(x) NULL
1020 #define get_errorlog_buffer() NULL
init_error_log_max(void)1021 static void __init init_error_log_max(void) {}
1022 #endif
1023
1024
1025 static void
va_rtas_call_unlocked(struct rtas_args * args,int token,int nargs,int nret,va_list list)1026 va_rtas_call_unlocked(struct rtas_args *args, int token, int nargs, int nret,
1027 va_list list)
1028 {
1029 int i;
1030
1031 args->token = cpu_to_be32(token);
1032 args->nargs = cpu_to_be32(nargs);
1033 args->nret = cpu_to_be32(nret);
1034 args->rets = &(args->args[nargs]);
1035
1036 for (i = 0; i < nargs; ++i)
1037 args->args[i] = cpu_to_be32(va_arg(list, __u32));
1038
1039 for (i = 0; i < nret; ++i)
1040 args->rets[i] = 0;
1041
1042 do_enter_rtas(args);
1043 }
1044
1045 /**
1046 * rtas_call_unlocked() - Invoke an RTAS firmware function without synchronization.
1047 * @args: RTAS parameter block to be used for the call, must obey RTAS addressing
1048 * constraints.
1049 * @token: Identifies the function being invoked.
1050 * @nargs: Number of input parameters. Does not include token.
1051 * @nret: Number of output parameters, including the call status.
1052 * @....: List of @nargs input parameters.
1053 *
1054 * Invokes the RTAS function indicated by @token, which the caller
1055 * should obtain via rtas_function_token().
1056 *
1057 * This function is similar to rtas_call(), but must be used with a
1058 * limited set of RTAS calls specifically exempted from the general
1059 * requirement that only one RTAS call may be in progress at any
1060 * time. Examples include stop-self and ibm,nmi-interlock.
1061 */
rtas_call_unlocked(struct rtas_args * args,int token,int nargs,int nret,...)1062 void rtas_call_unlocked(struct rtas_args *args, int token, int nargs, int nret, ...)
1063 {
1064 va_list list;
1065
1066 va_start(list, nret);
1067 va_rtas_call_unlocked(args, token, nargs, nret, list);
1068 va_end(list);
1069 }
1070
token_is_restricted_errinjct(s32 token)1071 static bool token_is_restricted_errinjct(s32 token)
1072 {
1073 return token == rtas_function_token(RTAS_FN_IBM_OPEN_ERRINJCT) ||
1074 token == rtas_function_token(RTAS_FN_IBM_ERRINJCT);
1075 }
1076
1077 /**
1078 * rtas_call() - Invoke an RTAS firmware function.
1079 * @token: Identifies the function being invoked.
1080 * @nargs: Number of input parameters. Does not include token.
1081 * @nret: Number of output parameters, including the call status.
1082 * @outputs: Array of @nret output words.
1083 * @....: List of @nargs input parameters.
1084 *
1085 * Invokes the RTAS function indicated by @token, which the caller
1086 * should obtain via rtas_function_token().
1087 *
1088 * The @nargs and @nret arguments must match the number of input and
1089 * output parameters specified for the RTAS function.
1090 *
1091 * rtas_call() returns RTAS status codes, not conventional Linux errno
1092 * values. Callers must translate any failure to an appropriate errno
1093 * in syscall context. Most callers of RTAS functions that can return
1094 * -2 or 990x should use rtas_busy_delay() to correctly handle those
1095 * statuses before calling again.
1096 *
1097 * The return value descriptions are adapted from 7.2.8 [RTAS] Return
1098 * Codes of the PAPR and CHRP specifications.
1099 *
1100 * Context: Process context preferably, interrupt context if
1101 * necessary. Acquires an internal spinlock and may perform
1102 * GFP_ATOMIC slab allocation in error path. Unsafe for NMI
1103 * context.
1104 * Return:
1105 * * 0 - RTAS function call succeeded.
1106 * * -1 - RTAS function encountered a hardware or
1107 * platform error, or the token is invalid,
1108 * or the function is restricted by kernel policy.
1109 * * -2 - Specs say "A necessary hardware device was busy,
1110 * and the requested function could not be
1111 * performed. The operation should be retried at
1112 * a later time." This is misleading, at least with
1113 * respect to current RTAS implementations. What it
1114 * usually means in practice is that the function
1115 * could not be completed while meeting RTAS's
1116 * deadline for returning control to the OS (250us
1117 * for PAPR/PowerVM, typically), but the call may be
1118 * immediately reattempted to resume work on it.
1119 * * -3 - Parameter error.
1120 * * -7 - Unexpected state change.
1121 * * 9000...9899 - Vendor-specific success codes.
1122 * * 9900...9905 - Advisory extended delay. Caller should try
1123 * again after ~10^x ms has elapsed, where x is
1124 * the last digit of the status [0-5]. Again going
1125 * beyond the PAPR text, 990x on PowerVM indicates
1126 * contention for RTAS-internal resources. Other
1127 * RTAS call sequences in progress should be
1128 * allowed to complete before reattempting the
1129 * call.
1130 * * -9000 - Multi-level isolation error.
1131 * * -9999...-9004 - Vendor-specific error codes.
1132 * * Additional negative values - Function-specific error.
1133 * * Additional positive values - Function-specific success.
1134 */
rtas_call(int token,int nargs,int nret,int * outputs,...)1135 int rtas_call(int token, int nargs, int nret, int *outputs, ...)
1136 {
1137 struct pin_cookie cookie;
1138 va_list list;
1139 int i;
1140 unsigned long flags;
1141 struct rtas_args *args;
1142 char *buff_copy = NULL;
1143 int ret;
1144
1145 if (!rtas.entry || token == RTAS_UNKNOWN_SERVICE)
1146 return -1;
1147
1148 if (token_is_restricted_errinjct(token)) {
1149 /*
1150 * It would be nicer to not discard the error value
1151 * from security_locked_down(), but callers expect an
1152 * RTAS status, not an errno.
1153 */
1154 if (security_locked_down(LOCKDOWN_RTAS_ERROR_INJECTION))
1155 return -1;
1156 }
1157
1158 if ((mfmsr() & (MSR_IR|MSR_DR)) != (MSR_IR|MSR_DR)) {
1159 WARN_ON_ONCE(1);
1160 return -1;
1161 }
1162
1163 raw_spin_lock_irqsave(&rtas_lock, flags);
1164 cookie = lockdep_pin_lock(&rtas_lock);
1165
1166 /* We use the global rtas args buffer */
1167 args = &rtas_args;
1168
1169 va_start(list, outputs);
1170 va_rtas_call_unlocked(args, token, nargs, nret, list);
1171 va_end(list);
1172
1173 /* A -1 return code indicates that the last command couldn't
1174 be completed due to a hardware error. */
1175 if (be32_to_cpu(args->rets[0]) == -1)
1176 buff_copy = __fetch_rtas_last_error(NULL);
1177
1178 if (nret > 1 && outputs != NULL)
1179 for (i = 0; i < nret-1; ++i)
1180 outputs[i] = be32_to_cpu(args->rets[i + 1]);
1181 ret = (nret > 0) ? be32_to_cpu(args->rets[0]) : 0;
1182
1183 lockdep_unpin_lock(&rtas_lock, cookie);
1184 raw_spin_unlock_irqrestore(&rtas_lock, flags);
1185
1186 if (buff_copy) {
1187 log_error(buff_copy, ERR_TYPE_RTAS_LOG, 0);
1188 if (slab_is_available())
1189 kfree(buff_copy);
1190 }
1191 return ret;
1192 }
1193 EXPORT_SYMBOL_GPL(rtas_call);
1194
1195 /**
1196 * rtas_busy_delay_time() - From an RTAS status value, calculate the
1197 * suggested delay time in milliseconds.
1198 *
1199 * @status: a value returned from rtas_call() or similar APIs which return
1200 * the status of a RTAS function call.
1201 *
1202 * Context: Any context.
1203 *
1204 * Return:
1205 * * 100000 - If @status is 9905.
1206 * * 10000 - If @status is 9904.
1207 * * 1000 - If @status is 9903.
1208 * * 100 - If @status is 9902.
1209 * * 10 - If @status is 9901.
1210 * * 1 - If @status is either 9900 or -2. This is "wrong" for -2, but
1211 * some callers depend on this behavior, and the worst outcome
1212 * is that they will delay for longer than necessary.
1213 * * 0 - If @status is not a busy or extended delay value.
1214 */
rtas_busy_delay_time(int status)1215 unsigned int rtas_busy_delay_time(int status)
1216 {
1217 int order;
1218 unsigned int ms = 0;
1219
1220 if (status == RTAS_BUSY) {
1221 ms = 1;
1222 } else if (status >= RTAS_EXTENDED_DELAY_MIN &&
1223 status <= RTAS_EXTENDED_DELAY_MAX) {
1224 order = status - RTAS_EXTENDED_DELAY_MIN;
1225 for (ms = 1; order > 0; order--)
1226 ms *= 10;
1227 }
1228
1229 return ms;
1230 }
1231
1232 /*
1233 * Early boot fallback for rtas_busy_delay().
1234 */
rtas_busy_delay_early(int status)1235 static bool __init rtas_busy_delay_early(int status)
1236 {
1237 static size_t successive_ext_delays __initdata;
1238 bool retry;
1239
1240 switch (status) {
1241 case RTAS_EXTENDED_DELAY_MIN...RTAS_EXTENDED_DELAY_MAX:
1242 /*
1243 * In the unlikely case that we receive an extended
1244 * delay status in early boot, the OS is probably not
1245 * the cause, and there's nothing we can do to clear
1246 * the condition. Best we can do is delay for a bit
1247 * and hope it's transient. Lie to the caller if it
1248 * seems like we're stuck in a retry loop.
1249 */
1250 mdelay(1);
1251 retry = true;
1252 successive_ext_delays += 1;
1253 if (successive_ext_delays > 1000) {
1254 pr_err("too many extended delays, giving up\n");
1255 dump_stack();
1256 retry = false;
1257 successive_ext_delays = 0;
1258 }
1259 break;
1260 case RTAS_BUSY:
1261 retry = true;
1262 successive_ext_delays = 0;
1263 break;
1264 default:
1265 retry = false;
1266 successive_ext_delays = 0;
1267 break;
1268 }
1269
1270 return retry;
1271 }
1272
1273 /**
1274 * rtas_busy_delay() - helper for RTAS busy and extended delay statuses
1275 *
1276 * @status: a value returned from rtas_call() or similar APIs which return
1277 * the status of a RTAS function call.
1278 *
1279 * Context: Process context. May sleep or schedule.
1280 *
1281 * Return:
1282 * * true - @status is RTAS_BUSY or an extended delay hint. The
1283 * caller may assume that the CPU has been yielded if necessary,
1284 * and that an appropriate delay for @status has elapsed.
1285 * Generally the caller should reattempt the RTAS call which
1286 * yielded @status.
1287 *
1288 * * false - @status is not @RTAS_BUSY nor an extended delay hint. The
1289 * caller is responsible for handling @status.
1290 */
rtas_busy_delay(int status)1291 bool __ref rtas_busy_delay(int status)
1292 {
1293 unsigned int ms;
1294 bool ret;
1295
1296 /*
1297 * Can't do timed sleeps before timekeeping is up.
1298 */
1299 if (system_state < SYSTEM_SCHEDULING)
1300 return rtas_busy_delay_early(status);
1301
1302 switch (status) {
1303 case RTAS_EXTENDED_DELAY_MIN...RTAS_EXTENDED_DELAY_MAX:
1304 ret = true;
1305 ms = rtas_busy_delay_time(status);
1306 /*
1307 * The extended delay hint can be as high as 100 seconds.
1308 * Surely any function returning such a status is either
1309 * buggy or isn't going to be significantly slowed by us
1310 * polling at 1HZ. Clamp the sleep time to one second.
1311 */
1312 ms = clamp(ms, 1U, 1000U);
1313 /*
1314 * The delay hint is an order-of-magnitude suggestion, not
1315 * a minimum. It is fine, possibly even advantageous, for
1316 * us to pause for less time than hinted. For small values,
1317 * use usleep_range() to ensure we don't sleep much longer
1318 * than actually needed.
1319 *
1320 * See Documentation/timers/timers-howto.rst for
1321 * explanation of the threshold used here. In effect we use
1322 * usleep_range() for 9900 and 9901, msleep() for
1323 * 9902-9905.
1324 */
1325 if (ms <= 20)
1326 usleep_range(ms * 100, ms * 1000);
1327 else
1328 msleep(ms);
1329 break;
1330 case RTAS_BUSY:
1331 ret = true;
1332 /*
1333 * We should call again immediately if there's no other
1334 * work to do.
1335 */
1336 cond_resched();
1337 break;
1338 default:
1339 ret = false;
1340 /*
1341 * Not a busy or extended delay status; the caller should
1342 * handle @status itself. Ensure we warn on misuses in
1343 * atomic context regardless.
1344 */
1345 might_sleep();
1346 break;
1347 }
1348
1349 return ret;
1350 }
1351 EXPORT_SYMBOL_GPL(rtas_busy_delay);
1352
rtas_error_rc(int rtas_rc)1353 int rtas_error_rc(int rtas_rc)
1354 {
1355 int rc;
1356
1357 switch (rtas_rc) {
1358 case RTAS_HARDWARE_ERROR: /* Hardware Error */
1359 rc = -EIO;
1360 break;
1361 case RTAS_INVALID_PARAMETER: /* Bad indicator/domain/etc */
1362 rc = -EINVAL;
1363 break;
1364 case -9000: /* Isolation error */
1365 rc = -EFAULT;
1366 break;
1367 case -9001: /* Outstanding TCE/PTE */
1368 rc = -EEXIST;
1369 break;
1370 case -9002: /* No usable slot */
1371 rc = -ENODEV;
1372 break;
1373 default:
1374 pr_err("%s: unexpected error %d\n", __func__, rtas_rc);
1375 rc = -ERANGE;
1376 break;
1377 }
1378 return rc;
1379 }
1380 EXPORT_SYMBOL_GPL(rtas_error_rc);
1381
rtas_get_power_level(int powerdomain,int * level)1382 int rtas_get_power_level(int powerdomain, int *level)
1383 {
1384 int token = rtas_function_token(RTAS_FN_GET_POWER_LEVEL);
1385 int rc;
1386
1387 if (token == RTAS_UNKNOWN_SERVICE)
1388 return -ENOENT;
1389
1390 while ((rc = rtas_call(token, 1, 2, level, powerdomain)) == RTAS_BUSY)
1391 udelay(1);
1392
1393 if (rc < 0)
1394 return rtas_error_rc(rc);
1395 return rc;
1396 }
1397 EXPORT_SYMBOL_GPL(rtas_get_power_level);
1398
rtas_set_power_level(int powerdomain,int level,int * setlevel)1399 int rtas_set_power_level(int powerdomain, int level, int *setlevel)
1400 {
1401 int token = rtas_function_token(RTAS_FN_SET_POWER_LEVEL);
1402 int rc;
1403
1404 if (token == RTAS_UNKNOWN_SERVICE)
1405 return -ENOENT;
1406
1407 do {
1408 rc = rtas_call(token, 2, 2, setlevel, powerdomain, level);
1409 } while (rtas_busy_delay(rc));
1410
1411 if (rc < 0)
1412 return rtas_error_rc(rc);
1413 return rc;
1414 }
1415 EXPORT_SYMBOL_GPL(rtas_set_power_level);
1416
rtas_get_sensor(int sensor,int index,int * state)1417 int rtas_get_sensor(int sensor, int index, int *state)
1418 {
1419 int token = rtas_function_token(RTAS_FN_GET_SENSOR_STATE);
1420 int rc;
1421
1422 if (token == RTAS_UNKNOWN_SERVICE)
1423 return -ENOENT;
1424
1425 do {
1426 rc = rtas_call(token, 2, 2, state, sensor, index);
1427 } while (rtas_busy_delay(rc));
1428
1429 if (rc < 0)
1430 return rtas_error_rc(rc);
1431 return rc;
1432 }
1433 EXPORT_SYMBOL_GPL(rtas_get_sensor);
1434
rtas_get_sensor_fast(int sensor,int index,int * state)1435 int rtas_get_sensor_fast(int sensor, int index, int *state)
1436 {
1437 int token = rtas_function_token(RTAS_FN_GET_SENSOR_STATE);
1438 int rc;
1439
1440 if (token == RTAS_UNKNOWN_SERVICE)
1441 return -ENOENT;
1442
1443 rc = rtas_call(token, 2, 2, state, sensor, index);
1444 WARN_ON(rc == RTAS_BUSY || (rc >= RTAS_EXTENDED_DELAY_MIN &&
1445 rc <= RTAS_EXTENDED_DELAY_MAX));
1446
1447 if (rc < 0)
1448 return rtas_error_rc(rc);
1449 return rc;
1450 }
1451
rtas_indicator_present(int token,int * maxindex)1452 bool rtas_indicator_present(int token, int *maxindex)
1453 {
1454 int proplen, count, i;
1455 const struct indicator_elem {
1456 __be32 token;
1457 __be32 maxindex;
1458 } *indicators;
1459
1460 indicators = of_get_property(rtas.dev, "rtas-indicators", &proplen);
1461 if (!indicators)
1462 return false;
1463
1464 count = proplen / sizeof(struct indicator_elem);
1465
1466 for (i = 0; i < count; i++) {
1467 if (__be32_to_cpu(indicators[i].token) != token)
1468 continue;
1469 if (maxindex)
1470 *maxindex = __be32_to_cpu(indicators[i].maxindex);
1471 return true;
1472 }
1473
1474 return false;
1475 }
1476
rtas_set_indicator(int indicator,int index,int new_value)1477 int rtas_set_indicator(int indicator, int index, int new_value)
1478 {
1479 int token = rtas_function_token(RTAS_FN_SET_INDICATOR);
1480 int rc;
1481
1482 if (token == RTAS_UNKNOWN_SERVICE)
1483 return -ENOENT;
1484
1485 do {
1486 rc = rtas_call(token, 3, 1, NULL, indicator, index, new_value);
1487 } while (rtas_busy_delay(rc));
1488
1489 if (rc < 0)
1490 return rtas_error_rc(rc);
1491 return rc;
1492 }
1493 EXPORT_SYMBOL_GPL(rtas_set_indicator);
1494
1495 /*
1496 * Ignoring RTAS extended delay
1497 */
rtas_set_indicator_fast(int indicator,int index,int new_value)1498 int rtas_set_indicator_fast(int indicator, int index, int new_value)
1499 {
1500 int token = rtas_function_token(RTAS_FN_SET_INDICATOR);
1501 int rc;
1502
1503 if (token == RTAS_UNKNOWN_SERVICE)
1504 return -ENOENT;
1505
1506 rc = rtas_call(token, 3, 1, NULL, indicator, index, new_value);
1507
1508 WARN_ON(rc == RTAS_BUSY || (rc >= RTAS_EXTENDED_DELAY_MIN &&
1509 rc <= RTAS_EXTENDED_DELAY_MAX));
1510
1511 if (rc < 0)
1512 return rtas_error_rc(rc);
1513
1514 return rc;
1515 }
1516
1517 /**
1518 * rtas_ibm_suspend_me() - Call ibm,suspend-me to suspend the LPAR.
1519 *
1520 * @fw_status: RTAS call status will be placed here if not NULL.
1521 *
1522 * rtas_ibm_suspend_me() should be called only on a CPU which has
1523 * received H_CONTINUE from the H_JOIN hcall. All other active CPUs
1524 * should be waiting to return from H_JOIN.
1525 *
1526 * rtas_ibm_suspend_me() may suspend execution of the OS
1527 * indefinitely. Callers should take appropriate measures upon return, such as
1528 * resetting watchdog facilities.
1529 *
1530 * Callers may choose to retry this call if @fw_status is
1531 * %RTAS_THREADS_ACTIVE.
1532 *
1533 * Return:
1534 * 0 - The partition has resumed from suspend, possibly after
1535 * migration to a different host.
1536 * -ECANCELED - The operation was aborted.
1537 * -EAGAIN - There were other CPUs not in H_JOIN at the time of the call.
1538 * -EBUSY - Some other condition prevented the suspend from succeeding.
1539 * -EIO - Hardware/platform error.
1540 */
rtas_ibm_suspend_me(int * fw_status)1541 int rtas_ibm_suspend_me(int *fw_status)
1542 {
1543 int token = rtas_function_token(RTAS_FN_IBM_SUSPEND_ME);
1544 int fwrc;
1545 int ret;
1546
1547 fwrc = rtas_call(token, 0, 1, NULL);
1548
1549 switch (fwrc) {
1550 case 0:
1551 ret = 0;
1552 break;
1553 case RTAS_SUSPEND_ABORTED:
1554 ret = -ECANCELED;
1555 break;
1556 case RTAS_THREADS_ACTIVE:
1557 ret = -EAGAIN;
1558 break;
1559 case RTAS_NOT_SUSPENDABLE:
1560 case RTAS_OUTSTANDING_COPROC:
1561 ret = -EBUSY;
1562 break;
1563 case -1:
1564 default:
1565 ret = -EIO;
1566 break;
1567 }
1568
1569 if (fw_status)
1570 *fw_status = fwrc;
1571
1572 return ret;
1573 }
1574
rtas_restart(char * cmd)1575 void __noreturn rtas_restart(char *cmd)
1576 {
1577 if (rtas_flash_term_hook)
1578 rtas_flash_term_hook(SYS_RESTART);
1579 pr_emerg("system-reboot returned %d\n",
1580 rtas_call(rtas_function_token(RTAS_FN_SYSTEM_REBOOT), 0, 1, NULL));
1581 for (;;);
1582 }
1583
rtas_power_off(void)1584 void rtas_power_off(void)
1585 {
1586 if (rtas_flash_term_hook)
1587 rtas_flash_term_hook(SYS_POWER_OFF);
1588 /* allow power on only with power button press */
1589 pr_emerg("power-off returned %d\n",
1590 rtas_call(rtas_function_token(RTAS_FN_POWER_OFF), 2, 1, NULL, -1, -1));
1591 for (;;);
1592 }
1593
rtas_halt(void)1594 void __noreturn rtas_halt(void)
1595 {
1596 if (rtas_flash_term_hook)
1597 rtas_flash_term_hook(SYS_HALT);
1598 /* allow power on only with power button press */
1599 pr_emerg("power-off returned %d\n",
1600 rtas_call(rtas_function_token(RTAS_FN_POWER_OFF), 2, 1, NULL, -1, -1));
1601 for (;;);
1602 }
1603
1604 /* Must be in the RMO region, so we place it here */
1605 static char rtas_os_term_buf[2048];
1606 static bool ibm_extended_os_term;
1607
rtas_os_term(char * str)1608 void rtas_os_term(char *str)
1609 {
1610 s32 token = rtas_function_token(RTAS_FN_IBM_OS_TERM);
1611 static struct rtas_args args;
1612 int status;
1613
1614 /*
1615 * Firmware with the ibm,extended-os-term property is guaranteed
1616 * to always return from an ibm,os-term call. Earlier versions without
1617 * this property may terminate the partition which we want to avoid
1618 * since it interferes with panic_timeout.
1619 */
1620
1621 if (token == RTAS_UNKNOWN_SERVICE || !ibm_extended_os_term)
1622 return;
1623
1624 snprintf(rtas_os_term_buf, 2048, "OS panic: %s", str);
1625
1626 /*
1627 * Keep calling as long as RTAS returns a "try again" status,
1628 * but don't use rtas_busy_delay(), which potentially
1629 * schedules.
1630 */
1631 do {
1632 rtas_call_unlocked(&args, token, 1, 1, NULL, __pa(rtas_os_term_buf));
1633 status = be32_to_cpu(args.rets[0]);
1634 } while (rtas_busy_delay_time(status));
1635
1636 if (status != 0)
1637 pr_emerg("ibm,os-term call failed %d\n", status);
1638 }
1639
1640 /**
1641 * rtas_activate_firmware() - Activate a new version of firmware.
1642 *
1643 * Context: This function may sleep.
1644 *
1645 * Activate a new version of partition firmware. The OS must call this
1646 * after resuming from a partition hibernation or migration in order
1647 * to maintain the ability to perform live firmware updates. It's not
1648 * catastrophic for this method to be absent or to fail; just log the
1649 * condition in that case.
1650 */
rtas_activate_firmware(void)1651 void rtas_activate_firmware(void)
1652 {
1653 int token = rtas_function_token(RTAS_FN_IBM_ACTIVATE_FIRMWARE);
1654 int fwrc;
1655
1656 if (token == RTAS_UNKNOWN_SERVICE) {
1657 pr_notice("ibm,activate-firmware method unavailable\n");
1658 return;
1659 }
1660
1661 do {
1662 fwrc = rtas_call(token, 0, 1, NULL);
1663 } while (rtas_busy_delay(fwrc));
1664
1665 if (fwrc)
1666 pr_err("ibm,activate-firmware failed (%i)\n", fwrc);
1667 }
1668
1669 /**
1670 * get_pseries_errorlog() - Find a specific pseries error log in an RTAS
1671 * extended event log.
1672 * @log: RTAS error/event log
1673 * @section_id: two character section identifier
1674 *
1675 * Return: A pointer to the specified errorlog or NULL if not found.
1676 */
get_pseries_errorlog(struct rtas_error_log * log,uint16_t section_id)1677 noinstr struct pseries_errorlog *get_pseries_errorlog(struct rtas_error_log *log,
1678 uint16_t section_id)
1679 {
1680 struct rtas_ext_event_log_v6 *ext_log =
1681 (struct rtas_ext_event_log_v6 *)log->buffer;
1682 struct pseries_errorlog *sect;
1683 unsigned char *p, *log_end;
1684 uint32_t ext_log_length = rtas_error_extended_log_length(log);
1685 uint8_t log_format = rtas_ext_event_log_format(ext_log);
1686 uint32_t company_id = rtas_ext_event_company_id(ext_log);
1687
1688 /* Check that we understand the format */
1689 if (ext_log_length < sizeof(struct rtas_ext_event_log_v6) ||
1690 log_format != RTAS_V6EXT_LOG_FORMAT_EVENT_LOG ||
1691 company_id != RTAS_V6EXT_COMPANY_ID_IBM)
1692 return NULL;
1693
1694 log_end = log->buffer + ext_log_length;
1695 p = ext_log->vendor_log;
1696
1697 while (p < log_end) {
1698 sect = (struct pseries_errorlog *)p;
1699 if (pseries_errorlog_id(sect) == section_id)
1700 return sect;
1701 p += pseries_errorlog_length(sect);
1702 }
1703
1704 return NULL;
1705 }
1706
1707 /*
1708 * The sys_rtas syscall, as originally designed, allows root to pass
1709 * arbitrary physical addresses to RTAS calls. A number of RTAS calls
1710 * can be abused to write to arbitrary memory and do other things that
1711 * are potentially harmful to system integrity, and thus should only
1712 * be used inside the kernel and not exposed to userspace.
1713 *
1714 * All known legitimate users of the sys_rtas syscall will only ever
1715 * pass addresses that fall within the RMO buffer, and use a known
1716 * subset of RTAS calls.
1717 *
1718 * Accordingly, we filter RTAS requests to check that the call is
1719 * permitted, and that provided pointers fall within the RMO buffer.
1720 * If a function is allowed to be invoked via the syscall, then its
1721 * entry in the rtas_functions table points to a rtas_filter that
1722 * describes its constraints, with the indexes of the parameters which
1723 * are expected to contain addresses and sizes of buffers allocated
1724 * inside the RMO buffer.
1725 */
1726
in_rmo_buf(u32 base,u32 end)1727 static bool in_rmo_buf(u32 base, u32 end)
1728 {
1729 return base >= rtas_rmo_buf &&
1730 base < (rtas_rmo_buf + RTAS_USER_REGION_SIZE) &&
1731 base <= end &&
1732 end >= rtas_rmo_buf &&
1733 end < (rtas_rmo_buf + RTAS_USER_REGION_SIZE);
1734 }
1735
block_rtas_call(int token,int nargs,struct rtas_args * args)1736 static bool block_rtas_call(int token, int nargs,
1737 struct rtas_args *args)
1738 {
1739 const struct rtas_function *func;
1740 const struct rtas_filter *f;
1741 const bool is_platform_dump = token == rtas_function_token(RTAS_FN_IBM_PLATFORM_DUMP);
1742 const bool is_config_conn = token == rtas_function_token(RTAS_FN_IBM_CONFIGURE_CONNECTOR);
1743 u32 base, size, end;
1744
1745 /*
1746 * If this token doesn't correspond to a function the kernel
1747 * understands, you're not allowed to call it.
1748 */
1749 func = rtas_token_to_function_untrusted(token);
1750 if (!func)
1751 goto err;
1752 /*
1753 * And only functions with filters attached are allowed.
1754 */
1755 f = func->filter;
1756 if (!f)
1757 goto err;
1758 /*
1759 * And some functions aren't allowed on LE.
1760 */
1761 if (IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN) && func->banned_for_syscall_on_le)
1762 goto err;
1763
1764 if (f->buf_idx1 != -1) {
1765 base = be32_to_cpu(args->args[f->buf_idx1]);
1766 if (f->size_idx1 != -1)
1767 size = be32_to_cpu(args->args[f->size_idx1]);
1768 else if (f->fixed_size)
1769 size = f->fixed_size;
1770 else
1771 size = 1;
1772
1773 end = base + size - 1;
1774
1775 /*
1776 * Special case for ibm,platform-dump - NULL buffer
1777 * address is used to indicate end of dump processing
1778 */
1779 if (is_platform_dump && base == 0)
1780 return false;
1781
1782 if (!in_rmo_buf(base, end))
1783 goto err;
1784 }
1785
1786 if (f->buf_idx2 != -1) {
1787 base = be32_to_cpu(args->args[f->buf_idx2]);
1788 if (f->size_idx2 != -1)
1789 size = be32_to_cpu(args->args[f->size_idx2]);
1790 else if (f->fixed_size)
1791 size = f->fixed_size;
1792 else
1793 size = 1;
1794 end = base + size - 1;
1795
1796 /*
1797 * Special case for ibm,configure-connector where the
1798 * address can be 0
1799 */
1800 if (is_config_conn && base == 0)
1801 return false;
1802
1803 if (!in_rmo_buf(base, end))
1804 goto err;
1805 }
1806
1807 return false;
1808 err:
1809 pr_err_ratelimited("sys_rtas: RTAS call blocked - exploit attempt?\n");
1810 pr_err_ratelimited("sys_rtas: token=0x%x, nargs=%d (called by %s)\n",
1811 token, nargs, current->comm);
1812 return true;
1813 }
1814
1815 /* We assume to be passed big endian arguments */
SYSCALL_DEFINE1(rtas,struct rtas_args __user *,uargs)1816 SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs)
1817 {
1818 struct pin_cookie cookie;
1819 struct rtas_args args;
1820 unsigned long flags;
1821 char *buff_copy, *errbuf = NULL;
1822 int nargs, nret, token;
1823
1824 if (!capable(CAP_SYS_ADMIN))
1825 return -EPERM;
1826
1827 if (!rtas.entry)
1828 return -EINVAL;
1829
1830 if (copy_from_user(&args, uargs, 3 * sizeof(u32)) != 0)
1831 return -EFAULT;
1832
1833 nargs = be32_to_cpu(args.nargs);
1834 nret = be32_to_cpu(args.nret);
1835 token = be32_to_cpu(args.token);
1836
1837 if (nargs >= ARRAY_SIZE(args.args)
1838 || nret > ARRAY_SIZE(args.args)
1839 || nargs + nret > ARRAY_SIZE(args.args))
1840 return -EINVAL;
1841
1842 /* Copy in args. */
1843 if (copy_from_user(args.args, uargs->args,
1844 nargs * sizeof(rtas_arg_t)) != 0)
1845 return -EFAULT;
1846
1847 if (token == RTAS_UNKNOWN_SERVICE)
1848 return -EINVAL;
1849
1850 args.rets = &args.args[nargs];
1851 memset(args.rets, 0, nret * sizeof(rtas_arg_t));
1852
1853 if (block_rtas_call(token, nargs, &args))
1854 return -EINVAL;
1855
1856 if (token_is_restricted_errinjct(token)) {
1857 int err;
1858
1859 err = security_locked_down(LOCKDOWN_RTAS_ERROR_INJECTION);
1860 if (err)
1861 return err;
1862 }
1863
1864 /* Need to handle ibm,suspend_me call specially */
1865 if (token == rtas_function_token(RTAS_FN_IBM_SUSPEND_ME)) {
1866
1867 /*
1868 * rtas_ibm_suspend_me assumes the streamid handle is in cpu
1869 * endian, or at least the hcall within it requires it.
1870 */
1871 int rc = 0;
1872 u64 handle = ((u64)be32_to_cpu(args.args[0]) << 32)
1873 | be32_to_cpu(args.args[1]);
1874 rc = rtas_syscall_dispatch_ibm_suspend_me(handle);
1875 if (rc == -EAGAIN)
1876 args.rets[0] = cpu_to_be32(RTAS_NOT_SUSPENDABLE);
1877 else if (rc == -EIO)
1878 args.rets[0] = cpu_to_be32(-1);
1879 else if (rc)
1880 return rc;
1881 goto copy_return;
1882 }
1883
1884 buff_copy = get_errorlog_buffer();
1885
1886 raw_spin_lock_irqsave(&rtas_lock, flags);
1887 cookie = lockdep_pin_lock(&rtas_lock);
1888
1889 rtas_args = args;
1890 do_enter_rtas(&rtas_args);
1891 args = rtas_args;
1892
1893 /* A -1 return code indicates that the last command couldn't
1894 be completed due to a hardware error. */
1895 if (be32_to_cpu(args.rets[0]) == -1)
1896 errbuf = __fetch_rtas_last_error(buff_copy);
1897
1898 lockdep_unpin_lock(&rtas_lock, cookie);
1899 raw_spin_unlock_irqrestore(&rtas_lock, flags);
1900
1901 if (buff_copy) {
1902 if (errbuf)
1903 log_error(errbuf, ERR_TYPE_RTAS_LOG, 0);
1904 kfree(buff_copy);
1905 }
1906
1907 copy_return:
1908 /* Copy out args. */
1909 if (copy_to_user(uargs->args + nargs,
1910 args.args + nargs,
1911 nret * sizeof(rtas_arg_t)) != 0)
1912 return -EFAULT;
1913
1914 return 0;
1915 }
1916
rtas_function_table_init(void)1917 static void __init rtas_function_table_init(void)
1918 {
1919 struct property *prop;
1920
1921 for (size_t i = 0; i < ARRAY_SIZE(rtas_function_table); ++i) {
1922 struct rtas_function *curr = &rtas_function_table[i];
1923 struct rtas_function *prior;
1924 int cmp;
1925
1926 curr->token = RTAS_UNKNOWN_SERVICE;
1927
1928 if (i == 0)
1929 continue;
1930 /*
1931 * Ensure table is sorted correctly for binary search
1932 * on function names.
1933 */
1934 prior = &rtas_function_table[i - 1];
1935
1936 cmp = strcmp(prior->name, curr->name);
1937 if (cmp < 0)
1938 continue;
1939
1940 if (cmp == 0) {
1941 pr_err("'%s' has duplicate function table entries\n",
1942 curr->name);
1943 } else {
1944 pr_err("function table unsorted: '%s' wrongly precedes '%s'\n",
1945 prior->name, curr->name);
1946 }
1947 }
1948
1949 for_each_property_of_node(rtas.dev, prop) {
1950 struct rtas_function *func;
1951
1952 if (prop->length != sizeof(u32))
1953 continue;
1954
1955 func = __rtas_name_to_function(prop->name);
1956 if (!func)
1957 continue;
1958
1959 func->token = be32_to_cpup((__be32 *)prop->value);
1960
1961 pr_debug("function %s has token %u\n", func->name, func->token);
1962 }
1963 }
1964
1965 /*
1966 * Call early during boot, before mem init, to retrieve the RTAS
1967 * information from the device-tree and allocate the RMO buffer for userland
1968 * accesses.
1969 */
rtas_initialize(void)1970 void __init rtas_initialize(void)
1971 {
1972 unsigned long rtas_region = RTAS_INSTANTIATE_MAX;
1973 u32 base, size, entry;
1974 int no_base, no_size, no_entry;
1975
1976 /* Get RTAS dev node and fill up our "rtas" structure with infos
1977 * about it.
1978 */
1979 rtas.dev = of_find_node_by_name(NULL, "rtas");
1980 if (!rtas.dev)
1981 return;
1982
1983 no_base = of_property_read_u32(rtas.dev, "linux,rtas-base", &base);
1984 no_size = of_property_read_u32(rtas.dev, "rtas-size", &size);
1985 if (no_base || no_size) {
1986 of_node_put(rtas.dev);
1987 rtas.dev = NULL;
1988 return;
1989 }
1990
1991 rtas.base = base;
1992 rtas.size = size;
1993 no_entry = of_property_read_u32(rtas.dev, "linux,rtas-entry", &entry);
1994 rtas.entry = no_entry ? rtas.base : entry;
1995
1996 init_error_log_max();
1997
1998 /* Must be called before any function token lookups */
1999 rtas_function_table_init();
2000
2001 /*
2002 * Discover this now to avoid a device tree lookup in the
2003 * panic path.
2004 */
2005 ibm_extended_os_term = of_property_read_bool(rtas.dev, "ibm,extended-os-term");
2006
2007 /* If RTAS was found, allocate the RMO buffer for it and look for
2008 * the stop-self token if any
2009 */
2010 #ifdef CONFIG_PPC64
2011 if (firmware_has_feature(FW_FEATURE_LPAR))
2012 rtas_region = min(ppc64_rma_size, RTAS_INSTANTIATE_MAX);
2013 #endif
2014 rtas_rmo_buf = memblock_phys_alloc_range(RTAS_USER_REGION_SIZE, PAGE_SIZE,
2015 0, rtas_region);
2016 if (!rtas_rmo_buf)
2017 panic("ERROR: RTAS: Failed to allocate %lx bytes below %pa\n",
2018 PAGE_SIZE, &rtas_region);
2019
2020 rtas_work_area_reserve_arena(rtas_region);
2021 }
2022
early_init_dt_scan_rtas(unsigned long node,const char * uname,int depth,void * data)2023 int __init early_init_dt_scan_rtas(unsigned long node,
2024 const char *uname, int depth, void *data)
2025 {
2026 const u32 *basep, *entryp, *sizep;
2027
2028 if (depth != 1 || strcmp(uname, "rtas") != 0)
2029 return 0;
2030
2031 basep = of_get_flat_dt_prop(node, "linux,rtas-base", NULL);
2032 entryp = of_get_flat_dt_prop(node, "linux,rtas-entry", NULL);
2033 sizep = of_get_flat_dt_prop(node, "rtas-size", NULL);
2034
2035 #ifdef CONFIG_PPC64
2036 /* need this feature to decide the crashkernel offset */
2037 if (of_get_flat_dt_prop(node, "ibm,hypertas-functions", NULL))
2038 powerpc_firmware_features |= FW_FEATURE_LPAR;
2039 #endif
2040
2041 if (basep && entryp && sizep) {
2042 rtas.base = *basep;
2043 rtas.entry = *entryp;
2044 rtas.size = *sizep;
2045 }
2046
2047 #ifdef CONFIG_UDBG_RTAS_CONSOLE
2048 basep = of_get_flat_dt_prop(node, "put-term-char", NULL);
2049 if (basep)
2050 rtas_putchar_token = *basep;
2051
2052 basep = of_get_flat_dt_prop(node, "get-term-char", NULL);
2053 if (basep)
2054 rtas_getchar_token = *basep;
2055
2056 if (rtas_putchar_token != RTAS_UNKNOWN_SERVICE &&
2057 rtas_getchar_token != RTAS_UNKNOWN_SERVICE)
2058 udbg_init_rtas_console();
2059
2060 #endif
2061
2062 /* break now */
2063 return 1;
2064 }
2065
2066 static DEFINE_RAW_SPINLOCK(timebase_lock);
2067 static u64 timebase = 0;
2068
rtas_give_timebase(void)2069 void rtas_give_timebase(void)
2070 {
2071 unsigned long flags;
2072
2073 raw_spin_lock_irqsave(&timebase_lock, flags);
2074 hard_irq_disable();
2075 rtas_call(rtas_function_token(RTAS_FN_FREEZE_TIME_BASE), 0, 1, NULL);
2076 timebase = get_tb();
2077 raw_spin_unlock(&timebase_lock);
2078
2079 while (timebase)
2080 barrier();
2081 rtas_call(rtas_function_token(RTAS_FN_THAW_TIME_BASE), 0, 1, NULL);
2082 local_irq_restore(flags);
2083 }
2084
rtas_take_timebase(void)2085 void rtas_take_timebase(void)
2086 {
2087 while (!timebase)
2088 barrier();
2089 raw_spin_lock(&timebase_lock);
2090 set_tb(timebase >> 32, timebase & 0xffffffff);
2091 timebase = 0;
2092 raw_spin_unlock(&timebase_lock);
2093 }
2094