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/mutex.h>
22#include <linux/nospec.h>
23#include <linux/of.h>
24#include <linux/of_fdt.h>
25#include <linux/reboot.h>
26#include <linux/sched.h>
27#include <linux/security.h>
28#include <linux/slab.h>
29#include <linux/spinlock.h>
30#include <linux/stdarg.h>
31#include <linux/syscalls.h>
32#include <linux/types.h>
33#include <linux/uaccess.h>
34#include <linux/xarray.h>
35
36#include <asm/delay.h>
37#include <asm/firmware.h>
38#include <asm/interrupt.h>
39#include <asm/machdep.h>
40#include <asm/mmu.h>
41#include <asm/page.h>
42#include <asm/rtas-work-area.h>
43#include <asm/rtas.h>
44#include <asm/time.h>
45#include <asm/trace.h>
46#include <asm/udbg.h>
47
48struct rtas_filter {
49 /* Indexes into the args buffer, -1 if not used */
50 const int buf_idx1;
51 const int size_idx1;
52 const int buf_idx2;
53 const int size_idx2;
54 /*
55 * Assumed buffer size per the spec if the function does not
56 * have a size parameter, e.g. ibm,errinjct. 0 if unused.
57 */
58 const int fixed_size;
59};
60
61/**
62 * struct rtas_function - Descriptor for RTAS functions.
63 *
64 * @token: Value of @name if it exists under the /rtas node.
65 * @name: Function name.
66 * @filter: If non-NULL, invoking this function via the rtas syscall is
67 * generally allowed, and @filter describes constraints on the
68 * arguments. See also @banned_for_syscall_on_le.
69 * @banned_for_syscall_on_le: Set when call via sys_rtas is generally allowed
70 * but specifically restricted on ppc64le. Such
71 * functions are believed to have no users on
72 * ppc64le, and we want to keep it that way. It does
73 * not make sense for this to be set when @filter
74 * is NULL.
75 * @lock: Pointer to an optional dedicated per-function mutex. This
76 * should be set for functions that require multiple calls in
77 * sequence to complete a single operation, and such sequences
78 * will disrupt each other if allowed to interleave. Users of
79 * this function are required to hold the associated lock for
80 * the duration of the call sequence. Add an explanatory
81 * comment to the function table entry if setting this member.
82 */
83struct rtas_function {
84 s32 token;
85 const bool banned_for_syscall_on_le:1;
86 const char * const name;
87 const struct rtas_filter *filter;
88 struct mutex *lock;
89};
90
91/*
92 * Per-function locks for sequence-based RTAS functions.
93 */
94static DEFINE_MUTEX(rtas_ibm_activate_firmware_lock);
95static DEFINE_MUTEX(rtas_ibm_lpar_perftools_lock);
96DEFINE_MUTEX(rtas_ibm_physical_attestation_lock);
97DEFINE_MUTEX(rtas_ibm_get_vpd_lock);
98DEFINE_MUTEX(rtas_ibm_get_indices_lock);
99DEFINE_MUTEX(rtas_ibm_set_dynamic_indicator_lock);
100DEFINE_MUTEX(rtas_ibm_get_dynamic_sensor_state_lock);
101DEFINE_MUTEX(rtas_ibm_receive_hvpipe_msg_lock);
102DEFINE_MUTEX(rtas_ibm_send_hvpipe_msg_lock);
103
104static struct rtas_function rtas_function_table[] __ro_after_init = {
105 [RTAS_FNIDX__CHECK_EXCEPTION] = {
106 .name = "check-exception",
107 },
108 [RTAS_FNIDX__DISPLAY_CHARACTER] = {
109 .name = "display-character",
110 .filter = &(const struct rtas_filter) {
111 .buf_idx1 = -1, .size_idx1 = -1,
112 .buf_idx2 = -1, .size_idx2 = -1,
113 },
114 },
115 [RTAS_FNIDX__EVENT_SCAN] = {
116 .name = "event-scan",
117 },
118 [RTAS_FNIDX__FREEZE_TIME_BASE] = {
119 .name = "freeze-time-base",
120 },
121 [RTAS_FNIDX__GET_POWER_LEVEL] = {
122 .name = "get-power-level",
123 .filter = &(const struct rtas_filter) {
124 .buf_idx1 = -1, .size_idx1 = -1,
125 .buf_idx2 = -1, .size_idx2 = -1,
126 },
127 },
128 [RTAS_FNIDX__GET_SENSOR_STATE] = {
129 .name = "get-sensor-state",
130 .filter = &(const struct rtas_filter) {
131 .buf_idx1 = -1, .size_idx1 = -1,
132 .buf_idx2 = -1, .size_idx2 = -1,
133 },
134 },
135 [RTAS_FNIDX__GET_TERM_CHAR] = {
136 .name = "get-term-char",
137 },
138 [RTAS_FNIDX__GET_TIME_OF_DAY] = {
139 .name = "get-time-of-day",
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_ACTIVATE_FIRMWARE] = {
146 .name = "ibm,activate-firmware",
147 .filter = &(const struct rtas_filter) {
148 .buf_idx1 = -1, .size_idx1 = -1,
149 .buf_idx2 = -1, .size_idx2 = -1,
150 },
151 /*
152 * PAPR+ as of v2.13 doesn't explicitly impose any
153 * restriction, but this typically requires multiple
154 * calls before success, and there's no reason to
155 * allow sequences to interleave.
156 */
157 .lock = &rtas_ibm_activate_firmware_lock,
158 },
159 [RTAS_FNIDX__IBM_CBE_START_PTCAL] = {
160 .name = "ibm,cbe-start-ptcal",
161 },
162 [RTAS_FNIDX__IBM_CBE_STOP_PTCAL] = {
163 .name = "ibm,cbe-stop-ptcal",
164 },
165 [RTAS_FNIDX__IBM_CHANGE_MSI] = {
166 .name = "ibm,change-msi",
167 },
168 [RTAS_FNIDX__IBM_CLOSE_ERRINJCT] = {
169 .name = "ibm,close-errinjct",
170 .filter = &(const struct rtas_filter) {
171 .buf_idx1 = -1, .size_idx1 = -1,
172 .buf_idx2 = -1, .size_idx2 = -1,
173 },
174 },
175 [RTAS_FNIDX__IBM_CONFIGURE_BRIDGE] = {
176 .name = "ibm,configure-bridge",
177 },
178 [RTAS_FNIDX__IBM_CONFIGURE_CONNECTOR] = {
179 .name = "ibm,configure-connector",
180 .filter = &(const struct rtas_filter) {
181 .buf_idx1 = 0, .size_idx1 = -1,
182 .buf_idx2 = 1, .size_idx2 = -1,
183 .fixed_size = 4096,
184 },
185 },
186 [RTAS_FNIDX__IBM_CONFIGURE_KERNEL_DUMP] = {
187 .name = "ibm,configure-kernel-dump",
188 },
189 [RTAS_FNIDX__IBM_CONFIGURE_PE] = {
190 .name = "ibm,configure-pe",
191 },
192 [RTAS_FNIDX__IBM_CREATE_PE_DMA_WINDOW] = {
193 .name = "ibm,create-pe-dma-window",
194 },
195 [RTAS_FNIDX__IBM_DISPLAY_MESSAGE] = {
196 .name = "ibm,display-message",
197 .filter = &(const struct rtas_filter) {
198 .buf_idx1 = 0, .size_idx1 = -1,
199 .buf_idx2 = -1, .size_idx2 = -1,
200 },
201 },
202 [RTAS_FNIDX__IBM_ERRINJCT] = {
203 .name = "ibm,errinjct",
204 .filter = &(const struct rtas_filter) {
205 .buf_idx1 = 2, .size_idx1 = -1,
206 .buf_idx2 = -1, .size_idx2 = -1,
207 .fixed_size = 1024,
208 },
209 },
210 [RTAS_FNIDX__IBM_EXTI2C] = {
211 .name = "ibm,exti2c",
212 },
213 [RTAS_FNIDX__IBM_GET_CONFIG_ADDR_INFO] = {
214 .name = "ibm,get-config-addr-info",
215 },
216 [RTAS_FNIDX__IBM_GET_CONFIG_ADDR_INFO2] = {
217 .name = "ibm,get-config-addr-info2",
218 .filter = &(const struct rtas_filter) {
219 .buf_idx1 = -1, .size_idx1 = -1,
220 .buf_idx2 = -1, .size_idx2 = -1,
221 },
222 },
223 [RTAS_FNIDX__IBM_GET_DYNAMIC_SENSOR_STATE] = {
224 .name = "ibm,get-dynamic-sensor-state",
225 .filter = &(const struct rtas_filter) {
226 .buf_idx1 = 1, .size_idx1 = -1,
227 .buf_idx2 = -1, .size_idx2 = -1,
228 },
229 /*
230 * PAPR+ v2.13 R1–7.3.19–3 is explicit that the OS
231 * must not call ibm,get-dynamic-sensor-state with
232 * different inputs until a non-retry status has been
233 * returned.
234 */
235 .lock = &rtas_ibm_get_dynamic_sensor_state_lock,
236 },
237 [RTAS_FNIDX__IBM_GET_INDICES] = {
238 .name = "ibm,get-indices",
239 .filter = &(const struct rtas_filter) {
240 .buf_idx1 = 2, .size_idx1 = 3,
241 .buf_idx2 = -1, .size_idx2 = -1,
242 },
243 /*
244 * PAPR+ v2.13 R1–7.3.17–2 says that the OS must not
245 * interleave ibm,get-indices call sequences with
246 * different inputs.
247 */
248 .lock = &rtas_ibm_get_indices_lock,
249 },
250 [RTAS_FNIDX__IBM_GET_RIO_TOPOLOGY] = {
251 .name = "ibm,get-rio-topology",
252 },
253 [RTAS_FNIDX__IBM_GET_SYSTEM_PARAMETER] = {
254 .name = "ibm,get-system-parameter",
255 .filter = &(const struct rtas_filter) {
256 .buf_idx1 = 1, .size_idx1 = 2,
257 .buf_idx2 = -1, .size_idx2 = -1,
258 },
259 },
260 [RTAS_FNIDX__IBM_GET_VPD] = {
261 .name = "ibm,get-vpd",
262 .filter = &(const struct rtas_filter) {
263 .buf_idx1 = 0, .size_idx1 = -1,
264 .buf_idx2 = 1, .size_idx2 = 2,
265 },
266 /*
267 * PAPR+ v2.13 R1–7.3.20–4 indicates that sequences
268 * should not be allowed to interleave.
269 */
270 .lock = &rtas_ibm_get_vpd_lock,
271 },
272 [RTAS_FNIDX__IBM_GET_XIVE] = {
273 .name = "ibm,get-xive",
274 },
275 [RTAS_FNIDX__IBM_INT_OFF] = {
276 .name = "ibm,int-off",
277 },
278 [RTAS_FNIDX__IBM_INT_ON] = {
279 .name = "ibm,int-on",
280 },
281 [RTAS_FNIDX__IBM_IO_QUIESCE_ACK] = {
282 .name = "ibm,io-quiesce-ack",
283 },
284 [RTAS_FNIDX__IBM_LPAR_PERFTOOLS] = {
285 .name = "ibm,lpar-perftools",
286 .filter = &(const struct rtas_filter) {
287 .buf_idx1 = 2, .size_idx1 = 3,
288 .buf_idx2 = -1, .size_idx2 = -1,
289 },
290 /*
291 * PAPR+ v2.13 R1–7.3.26–6 says the OS should allow
292 * only one call sequence in progress at a time.
293 */
294 .lock = &rtas_ibm_lpar_perftools_lock,
295 },
296 [RTAS_FNIDX__IBM_MANAGE_FLASH_IMAGE] = {
297 .name = "ibm,manage-flash-image",
298 },
299 [RTAS_FNIDX__IBM_MANAGE_STORAGE_PRESERVATION] = {
300 .name = "ibm,manage-storage-preservation",
301 },
302 [RTAS_FNIDX__IBM_NMI_INTERLOCK] = {
303 .name = "ibm,nmi-interlock",
304 },
305 [RTAS_FNIDX__IBM_NMI_REGISTER] = {
306 .name = "ibm,nmi-register",
307 },
308 [RTAS_FNIDX__IBM_OPEN_ERRINJCT] = {
309 .name = "ibm,open-errinjct",
310 .filter = &(const struct rtas_filter) {
311 .buf_idx1 = -1, .size_idx1 = -1,
312 .buf_idx2 = -1, .size_idx2 = -1,
313 },
314 },
315 [RTAS_FNIDX__IBM_OPEN_SRIOV_ALLOW_UNFREEZE] = {
316 .name = "ibm,open-sriov-allow-unfreeze",
317 },
318 [RTAS_FNIDX__IBM_OPEN_SRIOV_MAP_PE_NUMBER] = {
319 .name = "ibm,open-sriov-map-pe-number",
320 },
321 [RTAS_FNIDX__IBM_OS_TERM] = {
322 .name = "ibm,os-term",
323 },
324 [RTAS_FNIDX__IBM_PARTNER_CONTROL] = {
325 .name = "ibm,partner-control",
326 },
327 [RTAS_FNIDX__IBM_PHYSICAL_ATTESTATION] = {
328 .name = "ibm,physical-attestation",
329 .filter = &(const struct rtas_filter) {
330 .buf_idx1 = 0, .size_idx1 = 1,
331 .buf_idx2 = -1, .size_idx2 = -1,
332 },
333 /*
334 * This follows a sequence-based pattern similar to
335 * ibm,get-vpd et al. Since PAPR+ restricts
336 * interleaving call sequences for other functions of
337 * this style, assume the restriction applies here,
338 * even though it's not explicit in the spec.
339 */
340 .lock = &rtas_ibm_physical_attestation_lock,
341 },
342 [RTAS_FNIDX__IBM_PLATFORM_DUMP] = {
343 .name = "ibm,platform-dump",
344 .filter = &(const struct rtas_filter) {
345 .buf_idx1 = 4, .size_idx1 = 5,
346 .buf_idx2 = -1, .size_idx2 = -1,
347 },
348 /*
349 * PAPR+ v2.13 7.3.3.4.1 indicates that concurrent
350 * sequences of ibm,platform-dump are allowed if they
351 * are operating on different dump tags. So leave the
352 * lock pointer unset for now. This may need
353 * reconsideration if kernel-internal users appear.
354 */
355 },
356 [RTAS_FNIDX__IBM_POWER_OFF_UPS] = {
357 .name = "ibm,power-off-ups",
358 },
359 [RTAS_FNIDX__IBM_QUERY_INTERRUPT_SOURCE_NUMBER] = {
360 .name = "ibm,query-interrupt-source-number",
361 },
362 [RTAS_FNIDX__IBM_QUERY_PE_DMA_WINDOW] = {
363 .name = "ibm,query-pe-dma-window",
364 },
365 [RTAS_FNIDX__IBM_READ_PCI_CONFIG] = {
366 .name = "ibm,read-pci-config",
367 },
368 [RTAS_FNIDX__IBM_READ_SLOT_RESET_STATE] = {
369 .name = "ibm,read-slot-reset-state",
370 .filter = &(const struct rtas_filter) {
371 .buf_idx1 = -1, .size_idx1 = -1,
372 .buf_idx2 = -1, .size_idx2 = -1,
373 },
374 },
375 [RTAS_FNIDX__IBM_READ_SLOT_RESET_STATE2] = {
376 .name = "ibm,read-slot-reset-state2",
377 },
378 [RTAS_FNIDX__IBM_RECEIVE_HVPIPE_MSG] {
379 .name = "ibm,receive-hvpipe-msg",
380 .filter = &(const struct rtas_filter) {
381 .buf_idx1 = 0, .size_idx1 = 1,
382 .buf_idx2 = -1, .size_idx2 = -1,
383 },
384 /*
385 * PAPR+ v2.13 R1–7.3.32.1
386 */
387 .lock = &rtas_ibm_receive_hvpipe_msg_lock,
388 },
389 [RTAS_FNIDX__IBM_REMOVE_PE_DMA_WINDOW] = {
390 .name = "ibm,remove-pe-dma-window",
391 },
392 [RTAS_FNIDX__IBM_RESET_PE_DMA_WINDOW] = {
393 /*
394 * Note: PAPR+ v2.13 7.3.31.4.1 spells this as
395 * "ibm,reset-pe-dma-windows" (plural), but RTAS
396 * implementations use the singular form in practice.
397 */
398 .name = "ibm,reset-pe-dma-window",
399 },
400 [RTAS_FNIDX__IBM_SCAN_LOG_DUMP] = {
401 .name = "ibm,scan-log-dump",
402 .filter = &(const struct rtas_filter) {
403 .buf_idx1 = 0, .size_idx1 = 1,
404 .buf_idx2 = -1, .size_idx2 = -1,
405 },
406 },
407 [RTAS_FNIDX__IBM_SEND_HVPIPE_MSG] {
408 .name = "ibm,send-hvpipe-msg",
409 .filter = &(const struct rtas_filter) {
410 .buf_idx1 = 1, .size_idx1 = -1,
411 .buf_idx2 = -1, .size_idx2 = -1,
412 },
413 /*
414 * PAPR+ v2.13 R1–7.3.32.2
415 */
416 .lock = &rtas_ibm_send_hvpipe_msg_lock,
417 },
418 [RTAS_FNIDX__IBM_SET_DYNAMIC_INDICATOR] = {
419 .name = "ibm,set-dynamic-indicator",
420 .filter = &(const struct rtas_filter) {
421 .buf_idx1 = 2, .size_idx1 = -1,
422 .buf_idx2 = -1, .size_idx2 = -1,
423 },
424 /*
425 * PAPR+ v2.13 R1–7.3.18–3 says the OS must not call
426 * this function with different inputs until a
427 * non-retry status has been returned.
428 */
429 .lock = &rtas_ibm_set_dynamic_indicator_lock,
430 },
431 [RTAS_FNIDX__IBM_SET_EEH_OPTION] = {
432 .name = "ibm,set-eeh-option",
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__IBM_SET_SLOT_RESET] = {
439 .name = "ibm,set-slot-reset",
440 },
441 [RTAS_FNIDX__IBM_SET_SYSTEM_PARAMETER] = {
442 .name = "ibm,set-system-parameter",
443 .filter = &(const struct rtas_filter) {
444 .buf_idx1 = 1, .size_idx1 = -1,
445 .buf_idx2 = -1, .size_idx2 = -1,
446 },
447 },
448 [RTAS_FNIDX__IBM_SET_XIVE] = {
449 .name = "ibm,set-xive",
450 },
451 [RTAS_FNIDX__IBM_SLOT_ERROR_DETAIL] = {
452 .name = "ibm,slot-error-detail",
453 },
454 [RTAS_FNIDX__IBM_SUSPEND_ME] = {
455 .name = "ibm,suspend-me",
456 .banned_for_syscall_on_le = true,
457 .filter = &(const struct rtas_filter) {
458 .buf_idx1 = -1, .size_idx1 = -1,
459 .buf_idx2 = -1, .size_idx2 = -1,
460 },
461 },
462 [RTAS_FNIDX__IBM_TUNE_DMA_PARMS] = {
463 .name = "ibm,tune-dma-parms",
464 },
465 [RTAS_FNIDX__IBM_UPDATE_FLASH_64_AND_REBOOT] = {
466 .name = "ibm,update-flash-64-and-reboot",
467 },
468 [RTAS_FNIDX__IBM_UPDATE_NODES] = {
469 .name = "ibm,update-nodes",
470 .banned_for_syscall_on_le = true,
471 .filter = &(const struct rtas_filter) {
472 .buf_idx1 = 0, .size_idx1 = -1,
473 .buf_idx2 = -1, .size_idx2 = -1,
474 .fixed_size = 4096,
475 },
476 },
477 [RTAS_FNIDX__IBM_UPDATE_PROPERTIES] = {
478 .name = "ibm,update-properties",
479 .banned_for_syscall_on_le = true,
480 .filter = &(const struct rtas_filter) {
481 .buf_idx1 = 0, .size_idx1 = -1,
482 .buf_idx2 = -1, .size_idx2 = -1,
483 .fixed_size = 4096,
484 },
485 },
486 [RTAS_FNIDX__IBM_VALIDATE_FLASH_IMAGE] = {
487 .name = "ibm,validate-flash-image",
488 },
489 [RTAS_FNIDX__IBM_WRITE_PCI_CONFIG] = {
490 .name = "ibm,write-pci-config",
491 },
492 [RTAS_FNIDX__NVRAM_FETCH] = {
493 .name = "nvram-fetch",
494 },
495 [RTAS_FNIDX__NVRAM_STORE] = {
496 .name = "nvram-store",
497 },
498 [RTAS_FNIDX__POWER_OFF] = {
499 .name = "power-off",
500 },
501 [RTAS_FNIDX__PUT_TERM_CHAR] = {
502 .name = "put-term-char",
503 },
504 [RTAS_FNIDX__QUERY_CPU_STOPPED_STATE] = {
505 .name = "query-cpu-stopped-state",
506 },
507 [RTAS_FNIDX__READ_PCI_CONFIG] = {
508 .name = "read-pci-config",
509 },
510 [RTAS_FNIDX__RTAS_LAST_ERROR] = {
511 .name = "rtas-last-error",
512 },
513 [RTAS_FNIDX__SET_INDICATOR] = {
514 .name = "set-indicator",
515 .filter = &(const struct rtas_filter) {
516 .buf_idx1 = -1, .size_idx1 = -1,
517 .buf_idx2 = -1, .size_idx2 = -1,
518 },
519 },
520 [RTAS_FNIDX__SET_POWER_LEVEL] = {
521 .name = "set-power-level",
522 .filter = &(const struct rtas_filter) {
523 .buf_idx1 = -1, .size_idx1 = -1,
524 .buf_idx2 = -1, .size_idx2 = -1,
525 },
526 },
527 [RTAS_FNIDX__SET_TIME_FOR_POWER_ON] = {
528 .name = "set-time-for-power-on",
529 .filter = &(const struct rtas_filter) {
530 .buf_idx1 = -1, .size_idx1 = -1,
531 .buf_idx2 = -1, .size_idx2 = -1,
532 },
533 },
534 [RTAS_FNIDX__SET_TIME_OF_DAY] = {
535 .name = "set-time-of-day",
536 .filter = &(const struct rtas_filter) {
537 .buf_idx1 = -1, .size_idx1 = -1,
538 .buf_idx2 = -1, .size_idx2 = -1,
539 },
540 },
541 [RTAS_FNIDX__START_CPU] = {
542 .name = "start-cpu",
543 },
544 [RTAS_FNIDX__STOP_SELF] = {
545 .name = "stop-self",
546 },
547 [RTAS_FNIDX__SYSTEM_REBOOT] = {
548 .name = "system-reboot",
549 },
550 [RTAS_FNIDX__THAW_TIME_BASE] = {
551 .name = "thaw-time-base",
552 },
553 [RTAS_FNIDX__WRITE_PCI_CONFIG] = {
554 .name = "write-pci-config",
555 },
556};
557
558#define for_each_rtas_function(funcp) \
559 for (funcp = &rtas_function_table[0]; \
560 funcp < &rtas_function_table[ARRAY_SIZE(rtas_function_table)]; \
561 ++funcp)
562
563/*
564 * Nearly all RTAS calls need to be serialized. All uses of the
565 * default rtas_args block must hold rtas_lock.
566 *
567 * Exceptions to the RTAS serialization requirement (e.g. stop-self)
568 * must use a separate rtas_args structure.
569 */
570static DEFINE_RAW_SPINLOCK(rtas_lock);
571static struct rtas_args rtas_args;
572
573/**
574 * rtas_function_token() - RTAS function token lookup.
575 * @handle: Function handle, e.g. RTAS_FN_EVENT_SCAN.
576 *
577 * Context: Any context.
578 * Return: the token value for the function if implemented by this platform,
579 * otherwise RTAS_UNKNOWN_SERVICE.
580 */
581s32 rtas_function_token(const rtas_fn_handle_t handle)
582{
583 const size_t index = handle.index;
584 const bool out_of_bounds = index >= ARRAY_SIZE(rtas_function_table);
585
586 if (WARN_ONCE(out_of_bounds, "invalid function index %zu", index))
587 return RTAS_UNKNOWN_SERVICE;
588 /*
589 * Various drivers attempt token lookups on non-RTAS
590 * platforms.
591 */
592 if (!rtas.dev)
593 return RTAS_UNKNOWN_SERVICE;
594
595 return rtas_function_table[index].token;
596}
597EXPORT_SYMBOL_GPL(rtas_function_token);
598
599static int rtas_function_cmp(const void *a, const void *b)
600{
601 const struct rtas_function *f1 = a;
602 const struct rtas_function *f2 = b;
603
604 return strcmp(f1->name, f2->name);
605}
606
607/*
608 * Boot-time initialization of the function table needs the lookup to
609 * return a non-const-qualified object. Use rtas_name_to_function()
610 * in all other contexts.
611 */
612static struct rtas_function *__rtas_name_to_function(const char *name)
613{
614 const struct rtas_function key = {
615 .name = name,
616 };
617 struct rtas_function *found;
618
619 found = bsearch(&key, rtas_function_table, ARRAY_SIZE(rtas_function_table),
620 sizeof(rtas_function_table[0]), rtas_function_cmp);
621
622 return found;
623}
624
625static const struct rtas_function *rtas_name_to_function(const char *name)
626{
627 return __rtas_name_to_function(name);
628}
629
630static DEFINE_XARRAY(rtas_token_to_function_xarray);
631
632static int __init rtas_token_to_function_xarray_init(void)
633{
634 const struct rtas_function *func;
635 int err = 0;
636
637 for_each_rtas_function(func) {
638 const s32 token = func->token;
639
640 if (token == RTAS_UNKNOWN_SERVICE)
641 continue;
642
643 err = xa_err(xa_store(&rtas_token_to_function_xarray,
644 token, (void *)func, GFP_KERNEL));
645 if (err)
646 break;
647 }
648
649 return err;
650}
651arch_initcall(rtas_token_to_function_xarray_init);
652
653/*
654 * For use by sys_rtas(), where the token value is provided by user
655 * space and we don't want to warn on failed lookups.
656 */
657static const struct rtas_function *rtas_token_to_function_untrusted(s32 token)
658{
659 return xa_load(&rtas_token_to_function_xarray, index: token);
660}
661
662/*
663 * Reverse lookup for deriving the function descriptor from a
664 * known-good token value in contexts where the former is not already
665 * available. @token must be valid, e.g. derived from the result of a
666 * prior lookup against the function table.
667 */
668static const struct rtas_function *rtas_token_to_function(s32 token)
669{
670 const struct rtas_function *func;
671
672 if (WARN_ONCE(token < 0, "invalid token %d", token))
673 return NULL;
674
675 func = rtas_token_to_function_untrusted(token);
676 if (func)
677 return func;
678 /*
679 * Fall back to linear scan in case the reverse mapping hasn't
680 * been initialized yet.
681 */
682 if (xa_empty(xa: &rtas_token_to_function_xarray)) {
683 for_each_rtas_function(func) {
684 if (func->token == token)
685 return func;
686 }
687 }
688
689 WARN_ONCE(true, "unexpected failed lookup for token %d", token);
690 return NULL;
691}
692
693/* This is here deliberately so it's only used in this file */
694void enter_rtas(unsigned long);
695
696static void __do_enter_rtas(struct rtas_args *args)
697{
698 enter_rtas(__pa(args));
699 srr_regs_clobbered(); /* rtas uses SRRs, invalidate */
700}
701
702static void __do_enter_rtas_trace(struct rtas_args *args)
703{
704 const struct rtas_function *func = rtas_token_to_function(be32_to_cpu(args->token));
705
706 /*
707 * If there is a per-function lock, it must be held by the
708 * caller.
709 */
710 if (func->lock)
711 lockdep_assert_held(func->lock);
712
713 if (args == &rtas_args)
714 lockdep_assert_held(&rtas_lock);
715
716 trace_rtas_input(args, func->name);
717 trace_rtas_ll_entry(args);
718
719 __do_enter_rtas(args);
720
721 trace_rtas_ll_exit(args);
722 trace_rtas_output(args, func->name);
723}
724
725static void do_enter_rtas(struct rtas_args *args)
726{
727 const unsigned long msr = mfmsr();
728 /*
729 * Situations where we want to skip any active tracepoints for
730 * safety reasons:
731 *
732 * 1. The last code executed on an offline CPU as it stops,
733 * i.e. we're about to call stop-self. The tracepoints'
734 * function name lookup uses xarray, which uses RCU, which
735 * isn't valid to call on an offline CPU. Any events
736 * emitted on an offline CPU will be discarded anyway.
737 *
738 * 2. In real mode, as when invoking ibm,nmi-interlock from
739 * the pseries MCE handler. We cannot count on trace
740 * buffers or the entries in rtas_token_to_function_xarray
741 * to be contained in the RMO.
742 */
743 const unsigned long mask = MSR_IR | MSR_DR;
744 const bool can_trace = likely(cpu_online(raw_smp_processor_id()) &&
745 (msr & mask) == mask);
746 /*
747 * Make sure MSR[RI] is currently enabled as it will be forced later
748 * in enter_rtas.
749 */
750 BUG_ON(!(msr & MSR_RI));
751
752 BUG_ON(!irqs_disabled());
753
754 hard_irq_disable(); /* Ensure MSR[EE] is disabled on PPC64 */
755
756 if (can_trace)
757 __do_enter_rtas_trace(args);
758 else
759 __do_enter_rtas(args);
760}
761
762struct rtas_t rtas;
763
764DEFINE_SPINLOCK(rtas_data_buf_lock);
765EXPORT_SYMBOL_GPL(rtas_data_buf_lock);
766
767char rtas_data_buf[RTAS_DATA_BUF_SIZE] __aligned(SZ_4K);
768EXPORT_SYMBOL_GPL(rtas_data_buf);
769
770unsigned long rtas_rmo_buf;
771
772/*
773 * If non-NULL, this gets called when the kernel terminates.
774 * This is done like this so rtas_flash can be a module.
775 */
776void (*rtas_flash_term_hook)(int);
777EXPORT_SYMBOL_GPL(rtas_flash_term_hook);
778
779/*
780 * call_rtas_display_status and call_rtas_display_status_delay
781 * are designed only for very early low-level debugging, which
782 * is why the token is hard-coded to 10.
783 */
784static void call_rtas_display_status(unsigned char c)
785{
786 unsigned long flags;
787
788 if (!rtas.base)
789 return;
790
791 raw_spin_lock_irqsave(&rtas_lock, flags);
792 rtas_call_unlocked(&rtas_args, 10, 1, 1, NULL, c);
793 raw_spin_unlock_irqrestore(&rtas_lock, flags);
794}
795
796static void call_rtas_display_status_delay(char c)
797{
798 static int pending_newline = 0; /* did last write end with unprinted newline? */
799 static int width = 16;
800
801 if (c == '\n') {
802 while (width-- > 0)
803 call_rtas_display_status(c: ' ');
804 width = 16;
805 mdelay(500);
806 pending_newline = 1;
807 } else {
808 if (pending_newline) {
809 call_rtas_display_status(c: '\r');
810 call_rtas_display_status(c: '\n');
811 }
812 pending_newline = 0;
813 if (width--) {
814 call_rtas_display_status(c);
815 udelay(usec: 10000);
816 }
817 }
818}
819
820void __init udbg_init_rtas_panel(void)
821{
822 udbg_putc = call_rtas_display_status_delay;
823}
824
825void rtas_progress(char *s, unsigned short hex)
826{
827 struct device_node *root;
828 int width;
829 const __be32 *p;
830 char *os;
831 static int display_character, set_indicator;
832 static int display_width, display_lines, form_feed;
833 static const int *row_width;
834 static DEFINE_SPINLOCK(progress_lock);
835 static int current_line;
836 static int pending_newline = 0; /* did last write end with unprinted newline? */
837
838 if (!rtas.base)
839 return;
840
841 if (display_width == 0) {
842 display_width = 0x10;
843 if ((root = of_find_node_by_path(path: "/rtas"))) {
844 if ((p = of_get_property(node: root,
845 name: "ibm,display-line-length", NULL)))
846 display_width = be32_to_cpu(*p);
847 if ((p = of_get_property(node: root,
848 name: "ibm,form-feed", NULL)))
849 form_feed = be32_to_cpu(*p);
850 if ((p = of_get_property(node: root,
851 name: "ibm,display-number-of-lines", NULL)))
852 display_lines = be32_to_cpu(*p);
853 row_width = of_get_property(node: root,
854 name: "ibm,display-truncation-length", NULL);
855 of_node_put(node: root);
856 }
857 display_character = rtas_function_token(RTAS_FN_DISPLAY_CHARACTER);
858 set_indicator = rtas_function_token(RTAS_FN_SET_INDICATOR);
859 }
860
861 if (display_character == RTAS_UNKNOWN_SERVICE) {
862 /* use hex display if available */
863 if (set_indicator != RTAS_UNKNOWN_SERVICE)
864 rtas_call(set_indicator, 3, 1, NULL, 6, 0, hex);
865 return;
866 }
867
868 spin_lock(lock: &progress_lock);
869
870 /*
871 * Last write ended with newline, but we didn't print it since
872 * it would just clear the bottom line of output. Print it now
873 * instead.
874 *
875 * If no newline is pending and form feed is supported, clear the
876 * display with a form feed; otherwise, print a CR to start output
877 * at the beginning of the line.
878 */
879 if (pending_newline) {
880 rtas_call(display_character, 1, 1, NULL, '\r');
881 rtas_call(display_character, 1, 1, NULL, '\n');
882 pending_newline = 0;
883 } else {
884 current_line = 0;
885 if (form_feed)
886 rtas_call(display_character, 1, 1, NULL,
887 (char)form_feed);
888 else
889 rtas_call(display_character, 1, 1, NULL, '\r');
890 }
891
892 if (row_width)
893 width = row_width[current_line];
894 else
895 width = display_width;
896 os = s;
897 while (*os) {
898 if (*os == '\n' || *os == '\r') {
899 /* If newline is the last character, save it
900 * until next call to avoid bumping up the
901 * display output.
902 */
903 if (*os == '\n' && !os[1]) {
904 pending_newline = 1;
905 current_line++;
906 if (current_line > display_lines-1)
907 current_line = display_lines-1;
908 spin_unlock(lock: &progress_lock);
909 return;
910 }
911
912 /* RTAS wants CR-LF, not just LF */
913
914 if (*os == '\n') {
915 rtas_call(display_character, 1, 1, NULL, '\r');
916 rtas_call(display_character, 1, 1, NULL, '\n');
917 } else {
918 /* CR might be used to re-draw a line, so we'll
919 * leave it alone and not add LF.
920 */
921 rtas_call(display_character, 1, 1, NULL, *os);
922 }
923
924 if (row_width)
925 width = row_width[current_line];
926 else
927 width = display_width;
928 } else {
929 width--;
930 rtas_call(display_character, 1, 1, NULL, *os);
931 }
932
933 os++;
934
935 /* if we overwrite the screen length */
936 if (width <= 0)
937 while ((*os != 0) && (*os != '\n') && (*os != '\r'))
938 os++;
939 }
940
941 spin_unlock(lock: &progress_lock);
942}
943EXPORT_SYMBOL_GPL(rtas_progress); /* needed by rtas_flash module */
944
945int rtas_token(const char *service)
946{
947 const struct rtas_function *func;
948 const __be32 *tokp;
949
950 if (rtas.dev == NULL)
951 return RTAS_UNKNOWN_SERVICE;
952
953 func = rtas_name_to_function(name: service);
954 if (func)
955 return func->token;
956 /*
957 * The caller is looking up a name that is not known to be an
958 * RTAS function. Either it's a function that needs to be
959 * added to the table, or they're misusing rtas_token() to
960 * access non-function properties of the /rtas node. Warn and
961 * fall back to the legacy behavior.
962 */
963 WARN_ONCE(1, "unknown function `%s`, should it be added to rtas_function_table?\n",
964 service);
965
966 tokp = of_get_property(node: rtas.dev, name: service, NULL);
967 return tokp ? be32_to_cpu(*tokp) : RTAS_UNKNOWN_SERVICE;
968}
969EXPORT_SYMBOL_GPL(rtas_token);
970
971#ifdef CONFIG_RTAS_ERROR_LOGGING
972
973static u32 rtas_error_log_max __ro_after_init = RTAS_ERROR_LOG_MAX;
974
975/*
976 * Return the firmware-specified size of the error log buffer
977 * for all rtas calls that require an error buffer argument.
978 * This includes 'check-exception' and 'rtas-last-error'.
979 */
980int rtas_get_error_log_max(void)
981{
982 return rtas_error_log_max;
983}
984
985static void __init init_error_log_max(void)
986{
987 static const char propname[] __initconst = "rtas-error-log-max";
988 u32 max;
989
990 if (of_property_read_u32(rtas.dev, propname, &max)) {
991 pr_warn("%s not found, using default of %u\n",
992 propname, RTAS_ERROR_LOG_MAX);
993 max = RTAS_ERROR_LOG_MAX;
994 }
995
996 if (max > RTAS_ERROR_LOG_MAX) {
997 pr_warn("%s = %u, clamping max error log size to %u\n",
998 propname, max, RTAS_ERROR_LOG_MAX);
999 max = RTAS_ERROR_LOG_MAX;
1000 }
1001
1002 rtas_error_log_max = max;
1003}
1004
1005
1006static char rtas_err_buf[RTAS_ERROR_LOG_MAX];
1007
1008/** Return a copy of the detailed error text associated with the
1009 * most recent failed call to rtas. Because the error text
1010 * might go stale if there are any other intervening rtas calls,
1011 * this routine must be called atomically with whatever produced
1012 * the error (i.e. with rtas_lock still held from the previous call).
1013 */
1014static char *__fetch_rtas_last_error(char *altbuf)
1015{
1016 const s32 token = rtas_function_token(RTAS_FN_RTAS_LAST_ERROR);
1017 struct rtas_args err_args, save_args;
1018 u32 bufsz;
1019 char *buf = NULL;
1020
1021 lockdep_assert_held(&rtas_lock);
1022
1023 if (token == -1)
1024 return NULL;
1025
1026 bufsz = rtas_get_error_log_max();
1027
1028 err_args.token = cpu_to_be32(token);
1029 err_args.nargs = cpu_to_be32(2);
1030 err_args.nret = cpu_to_be32(1);
1031 err_args.args[0] = cpu_to_be32(__pa(rtas_err_buf));
1032 err_args.args[1] = cpu_to_be32(bufsz);
1033 err_args.args[2] = 0;
1034
1035 save_args = rtas_args;
1036 rtas_args = err_args;
1037
1038 do_enter_rtas(&rtas_args);
1039
1040 err_args = rtas_args;
1041 rtas_args = save_args;
1042
1043 /* Log the error in the unlikely case that there was one. */
1044 if (unlikely(err_args.args[2] == 0)) {
1045 if (altbuf) {
1046 buf = altbuf;
1047 } else {
1048 buf = rtas_err_buf;
1049 if (slab_is_available())
1050 buf = kmalloc(RTAS_ERROR_LOG_MAX, GFP_ATOMIC);
1051 }
1052 if (buf)
1053 memmove(buf, rtas_err_buf, RTAS_ERROR_LOG_MAX);
1054 }
1055
1056 return buf;
1057}
1058
1059#define get_errorlog_buffer() kmalloc(RTAS_ERROR_LOG_MAX, GFP_KERNEL)
1060
1061#else /* CONFIG_RTAS_ERROR_LOGGING */
1062#define __fetch_rtas_last_error(x) NULL
1063#define get_errorlog_buffer() NULL
1064static void __init init_error_log_max(void) {}
1065#endif
1066
1067
1068static void
1069va_rtas_call_unlocked(struct rtas_args *args, int token, int nargs, int nret,
1070 va_list list)
1071{
1072 int i;
1073
1074 args->token = cpu_to_be32(token);
1075 args->nargs = cpu_to_be32(nargs);
1076 args->nret = cpu_to_be32(nret);
1077 args->rets = &(args->args[nargs]);
1078
1079 for (i = 0; i < nargs; ++i)
1080 args->args[i] = cpu_to_be32(va_arg(list, __u32));
1081
1082 for (i = 0; i < nret; ++i)
1083 args->rets[i] = 0;
1084
1085 do_enter_rtas(args);
1086}
1087
1088/**
1089 * rtas_call_unlocked() - Invoke an RTAS firmware function without synchronization.
1090 * @args: RTAS parameter block to be used for the call, must obey RTAS addressing
1091 * constraints.
1092 * @token: Identifies the function being invoked.
1093 * @nargs: Number of input parameters. Does not include token.
1094 * @nret: Number of output parameters, including the call status.
1095 * @....: List of @nargs input parameters.
1096 *
1097 * Invokes the RTAS function indicated by @token, which the caller
1098 * should obtain via rtas_function_token().
1099 *
1100 * This function is similar to rtas_call(), but must be used with a
1101 * limited set of RTAS calls specifically exempted from the general
1102 * requirement that only one RTAS call may be in progress at any
1103 * time. Examples include stop-self and ibm,nmi-interlock.
1104 */
1105void rtas_call_unlocked(struct rtas_args *args, int token, int nargs, int nret, ...)
1106{
1107 va_list list;
1108
1109 va_start(list, nret);
1110 va_rtas_call_unlocked(args, token, nargs, nret, list);
1111 va_end(list);
1112}
1113
1114static bool token_is_restricted_errinjct(s32 token)
1115{
1116 return token == rtas_function_token(RTAS_FN_IBM_OPEN_ERRINJCT) ||
1117 token == rtas_function_token(RTAS_FN_IBM_ERRINJCT);
1118}
1119
1120/**
1121 * rtas_call() - Invoke an RTAS firmware function.
1122 * @token: Identifies the function being invoked.
1123 * @nargs: Number of input parameters. Does not include token.
1124 * @nret: Number of output parameters, including the call status.
1125 * @outputs: Array of @nret output words.
1126 * @....: List of @nargs input parameters.
1127 *
1128 * Invokes the RTAS function indicated by @token, which the caller
1129 * should obtain via rtas_function_token().
1130 *
1131 * The @nargs and @nret arguments must match the number of input and
1132 * output parameters specified for the RTAS function.
1133 *
1134 * rtas_call() returns RTAS status codes, not conventional Linux errno
1135 * values. Callers must translate any failure to an appropriate errno
1136 * in syscall context. Most callers of RTAS functions that can return
1137 * -2 or 990x should use rtas_busy_delay() to correctly handle those
1138 * statuses before calling again.
1139 *
1140 * The return value descriptions are adapted from 7.2.8 [RTAS] Return
1141 * Codes of the PAPR and CHRP specifications.
1142 *
1143 * Context: Process context preferably, interrupt context if
1144 * necessary. Acquires an internal spinlock and may perform
1145 * GFP_ATOMIC slab allocation in error path. Unsafe for NMI
1146 * context.
1147 * Return:
1148 * * 0 - RTAS function call succeeded.
1149 * * -1 - RTAS function encountered a hardware or
1150 * platform error, or the token is invalid,
1151 * or the function is restricted by kernel policy.
1152 * * -2 - Specs say "A necessary hardware device was busy,
1153 * and the requested function could not be
1154 * performed. The operation should be retried at
1155 * a later time." This is misleading, at least with
1156 * respect to current RTAS implementations. What it
1157 * usually means in practice is that the function
1158 * could not be completed while meeting RTAS's
1159 * deadline for returning control to the OS (250us
1160 * for PAPR/PowerVM, typically), but the call may be
1161 * immediately reattempted to resume work on it.
1162 * * -3 - Parameter error.
1163 * * -7 - Unexpected state change.
1164 * * 9000...9899 - Vendor-specific success codes.
1165 * * 9900...9905 - Advisory extended delay. Caller should try
1166 * again after ~10^x ms has elapsed, where x is
1167 * the last digit of the status [0-5]. Again going
1168 * beyond the PAPR text, 990x on PowerVM indicates
1169 * contention for RTAS-internal resources. Other
1170 * RTAS call sequences in progress should be
1171 * allowed to complete before reattempting the
1172 * call.
1173 * * -9000 - Multi-level isolation error.
1174 * * -9999...-9004 - Vendor-specific error codes.
1175 * * Additional negative values - Function-specific error.
1176 * * Additional positive values - Function-specific success.
1177 */
1178int rtas_call(int token, int nargs, int nret, int *outputs, ...)
1179{
1180 struct pin_cookie cookie;
1181 va_list list;
1182 int i;
1183 unsigned long flags;
1184 struct rtas_args *args;
1185 char *buff_copy = NULL;
1186 int ret;
1187
1188 if (!rtas.entry || token == RTAS_UNKNOWN_SERVICE)
1189 return -1;
1190
1191 if (token_is_restricted_errinjct(token)) {
1192 /*
1193 * It would be nicer to not discard the error value
1194 * from security_locked_down(), but callers expect an
1195 * RTAS status, not an errno.
1196 */
1197 if (security_locked_down(what: LOCKDOWN_RTAS_ERROR_INJECTION))
1198 return -1;
1199 }
1200
1201 if ((mfmsr() & (MSR_IR|MSR_DR)) != (MSR_IR|MSR_DR)) {
1202 WARN_ON_ONCE(1);
1203 return -1;
1204 }
1205
1206 raw_spin_lock_irqsave(&rtas_lock, flags);
1207 cookie = lockdep_pin_lock(&rtas_lock);
1208
1209 /* We use the global rtas args buffer */
1210 args = &rtas_args;
1211
1212 va_start(list, outputs);
1213 va_rtas_call_unlocked(args, token, nargs, nret, list);
1214 va_end(list);
1215
1216 /* A -1 return code indicates that the last command couldn't
1217 be completed due to a hardware error. */
1218 if (be32_to_cpu(args->rets[0]) == -1)
1219 buff_copy = __fetch_rtas_last_error(NULL);
1220
1221 if (nret > 1 && outputs != NULL)
1222 for (i = 0; i < nret-1; ++i)
1223 outputs[i] = be32_to_cpu(args->rets[i + 1]);
1224 ret = (nret > 0) ? be32_to_cpu(args->rets[0]) : 0;
1225
1226 lockdep_unpin_lock(&rtas_lock, cookie);
1227 raw_spin_unlock_irqrestore(&rtas_lock, flags);
1228
1229 if (buff_copy) {
1230 log_error(buff_copy, ERR_TYPE_RTAS_LOG, 0);
1231 if (slab_is_available())
1232 kfree(objp: buff_copy);
1233 }
1234 return ret;
1235}
1236EXPORT_SYMBOL_GPL(rtas_call);
1237
1238/**
1239 * rtas_busy_delay_time() - From an RTAS status value, calculate the
1240 * suggested delay time in milliseconds.
1241 *
1242 * @status: a value returned from rtas_call() or similar APIs which return
1243 * the status of a RTAS function call.
1244 *
1245 * Context: Any context.
1246 *
1247 * Return:
1248 * * 100000 - If @status is 9905.
1249 * * 10000 - If @status is 9904.
1250 * * 1000 - If @status is 9903.
1251 * * 100 - If @status is 9902.
1252 * * 10 - If @status is 9901.
1253 * * 1 - If @status is either 9900 or -2. This is "wrong" for -2, but
1254 * some callers depend on this behavior, and the worst outcome
1255 * is that they will delay for longer than necessary.
1256 * * 0 - If @status is not a busy or extended delay value.
1257 */
1258unsigned int rtas_busy_delay_time(int status)
1259{
1260 int order;
1261 unsigned int ms = 0;
1262
1263 if (status == RTAS_BUSY) {
1264 ms = 1;
1265 } else if (status >= RTAS_EXTENDED_DELAY_MIN &&
1266 status <= RTAS_EXTENDED_DELAY_MAX) {
1267 order = status - RTAS_EXTENDED_DELAY_MIN;
1268 for (ms = 1; order > 0; order--)
1269 ms *= 10;
1270 }
1271
1272 return ms;
1273}
1274
1275/*
1276 * Early boot fallback for rtas_busy_delay().
1277 */
1278static bool __init rtas_busy_delay_early(int status)
1279{
1280 static size_t successive_ext_delays __initdata;
1281 bool retry;
1282
1283 switch (status) {
1284 case RTAS_EXTENDED_DELAY_MIN...RTAS_EXTENDED_DELAY_MAX:
1285 /*
1286 * In the unlikely case that we receive an extended
1287 * delay status in early boot, the OS is probably not
1288 * the cause, and there's nothing we can do to clear
1289 * the condition. Best we can do is delay for a bit
1290 * and hope it's transient. Lie to the caller if it
1291 * seems like we're stuck in a retry loop.
1292 */
1293 mdelay(1);
1294 retry = true;
1295 successive_ext_delays += 1;
1296 if (successive_ext_delays > 1000) {
1297 pr_err("too many extended delays, giving up\n");
1298 dump_stack();
1299 retry = false;
1300 successive_ext_delays = 0;
1301 }
1302 break;
1303 case RTAS_BUSY:
1304 retry = true;
1305 successive_ext_delays = 0;
1306 break;
1307 default:
1308 retry = false;
1309 successive_ext_delays = 0;
1310 break;
1311 }
1312
1313 return retry;
1314}
1315
1316/**
1317 * rtas_busy_delay() - helper for RTAS busy and extended delay statuses
1318 *
1319 * @status: a value returned from rtas_call() or similar APIs which return
1320 * the status of a RTAS function call.
1321 *
1322 * Context: Process context. May sleep or schedule.
1323 *
1324 * Return:
1325 * * true - @status is RTAS_BUSY or an extended delay hint. The
1326 * caller may assume that the CPU has been yielded if necessary,
1327 * and that an appropriate delay for @status has elapsed.
1328 * Generally the caller should reattempt the RTAS call which
1329 * yielded @status.
1330 *
1331 * * false - @status is not @RTAS_BUSY nor an extended delay hint. The
1332 * caller is responsible for handling @status.
1333 */
1334bool __ref rtas_busy_delay(int status)
1335{
1336 unsigned int ms;
1337 bool ret;
1338
1339 /*
1340 * Can't do timed sleeps before timekeeping is up.
1341 */
1342 if (system_state < SYSTEM_SCHEDULING)
1343 return rtas_busy_delay_early(status);
1344
1345 switch (status) {
1346 case RTAS_EXTENDED_DELAY_MIN...RTAS_EXTENDED_DELAY_MAX:
1347 ret = true;
1348 ms = rtas_busy_delay_time(status);
1349 /*
1350 * The extended delay hint can be as high as 100 seconds.
1351 * Surely any function returning such a status is either
1352 * buggy or isn't going to be significantly slowed by us
1353 * polling at 1HZ. Clamp the sleep time to one second.
1354 */
1355 ms = clamp(ms, 1U, 1000U);
1356 /*
1357 * The delay hint is an order-of-magnitude suggestion, not a
1358 * minimum. It is fine, possibly even advantageous, for us to
1359 * pause for less time than hinted. To make sure pause time will
1360 * not be way longer than requested independent of HZ
1361 * configuration, use fsleep(). See fsleep() for details of
1362 * used sleeping functions.
1363 */
1364 fsleep(usecs: ms * 1000);
1365 break;
1366 case RTAS_BUSY:
1367 ret = true;
1368 /*
1369 * We should call again immediately if there's no other
1370 * work to do.
1371 */
1372 cond_resched();
1373 break;
1374 default:
1375 ret = false;
1376 /*
1377 * Not a busy or extended delay status; the caller should
1378 * handle @status itself. Ensure we warn on misuses in
1379 * atomic context regardless.
1380 */
1381 might_sleep();
1382 break;
1383 }
1384
1385 return ret;
1386}
1387EXPORT_SYMBOL_GPL(rtas_busy_delay);
1388
1389int rtas_error_rc(int rtas_rc)
1390{
1391 int rc;
1392
1393 switch (rtas_rc) {
1394 case RTAS_HARDWARE_ERROR: /* Hardware Error */
1395 rc = -EIO;
1396 break;
1397 case RTAS_INVALID_PARAMETER: /* Bad indicator/domain/etc */
1398 rc = -EINVAL;
1399 break;
1400 case -9000: /* Isolation error */
1401 rc = -EFAULT;
1402 break;
1403 case -9001: /* Outstanding TCE/PTE */
1404 rc = -EEXIST;
1405 break;
1406 case -9002: /* No usable slot */
1407 rc = -ENODEV;
1408 break;
1409 default:
1410 pr_err("%s: unexpected error %d\n", __func__, rtas_rc);
1411 rc = -ERANGE;
1412 break;
1413 }
1414 return rc;
1415}
1416EXPORT_SYMBOL_GPL(rtas_error_rc);
1417
1418int rtas_get_power_level(int powerdomain, int *level)
1419{
1420 int token = rtas_function_token(RTAS_FN_GET_POWER_LEVEL);
1421 int rc;
1422
1423 if (token == RTAS_UNKNOWN_SERVICE)
1424 return -ENOENT;
1425
1426 while ((rc = rtas_call(token, 1, 2, level, powerdomain)) == RTAS_BUSY)
1427 udelay(usec: 1);
1428
1429 if (rc < 0)
1430 return rtas_error_rc(rc);
1431 return rc;
1432}
1433EXPORT_SYMBOL_GPL(rtas_get_power_level);
1434
1435int rtas_set_power_level(int powerdomain, int level, int *setlevel)
1436{
1437 int token = rtas_function_token(RTAS_FN_SET_POWER_LEVEL);
1438 int rc;
1439
1440 if (token == RTAS_UNKNOWN_SERVICE)
1441 return -ENOENT;
1442
1443 do {
1444 rc = rtas_call(token, 2, 2, setlevel, powerdomain, level);
1445 } while (rtas_busy_delay(rc));
1446
1447 if (rc < 0)
1448 return rtas_error_rc(rc);
1449 return rc;
1450}
1451EXPORT_SYMBOL_GPL(rtas_set_power_level);
1452
1453int rtas_get_sensor(int sensor, int index, int *state)
1454{
1455 int token = rtas_function_token(RTAS_FN_GET_SENSOR_STATE);
1456 int rc;
1457
1458 if (token == RTAS_UNKNOWN_SERVICE)
1459 return -ENOENT;
1460
1461 do {
1462 rc = rtas_call(token, 2, 2, state, sensor, index);
1463 } while (rtas_busy_delay(rc));
1464
1465 if (rc < 0)
1466 return rtas_error_rc(rc);
1467 return rc;
1468}
1469EXPORT_SYMBOL_GPL(rtas_get_sensor);
1470
1471int rtas_get_sensor_fast(int sensor, int index, int *state)
1472{
1473 int token = rtas_function_token(RTAS_FN_GET_SENSOR_STATE);
1474 int rc;
1475
1476 if (token == RTAS_UNKNOWN_SERVICE)
1477 return -ENOENT;
1478
1479 rc = rtas_call(token, 2, 2, state, sensor, index);
1480 WARN_ON(rc == RTAS_BUSY || (rc >= RTAS_EXTENDED_DELAY_MIN &&
1481 rc <= RTAS_EXTENDED_DELAY_MAX));
1482
1483 if (rc < 0)
1484 return rtas_error_rc(rc);
1485 return rc;
1486}
1487
1488bool rtas_indicator_present(int token, int *maxindex)
1489{
1490 int proplen, count, i;
1491 const struct indicator_elem {
1492 __be32 token;
1493 __be32 maxindex;
1494 } *indicators;
1495
1496 indicators = of_get_property(node: rtas.dev, name: "rtas-indicators", lenp: &proplen);
1497 if (!indicators)
1498 return false;
1499
1500 count = proplen / sizeof(struct indicator_elem);
1501
1502 for (i = 0; i < count; i++) {
1503 if (__be32_to_cpu(indicators[i].token) != token)
1504 continue;
1505 if (maxindex)
1506 *maxindex = __be32_to_cpu(indicators[i].maxindex);
1507 return true;
1508 }
1509
1510 return false;
1511}
1512
1513int rtas_set_indicator(int indicator, int index, int new_value)
1514{
1515 int token = rtas_function_token(RTAS_FN_SET_INDICATOR);
1516 int rc;
1517
1518 if (token == RTAS_UNKNOWN_SERVICE)
1519 return -ENOENT;
1520
1521 do {
1522 rc = rtas_call(token, 3, 1, NULL, indicator, index, new_value);
1523 } while (rtas_busy_delay(rc));
1524
1525 if (rc < 0)
1526 return rtas_error_rc(rc);
1527 return rc;
1528}
1529EXPORT_SYMBOL_GPL(rtas_set_indicator);
1530
1531/*
1532 * Ignoring RTAS extended delay
1533 */
1534int rtas_set_indicator_fast(int indicator, int index, int new_value)
1535{
1536 int token = rtas_function_token(RTAS_FN_SET_INDICATOR);
1537 int rc;
1538
1539 if (token == RTAS_UNKNOWN_SERVICE)
1540 return -ENOENT;
1541
1542 rc = rtas_call(token, 3, 1, NULL, indicator, index, new_value);
1543
1544 WARN_ON(rc == RTAS_BUSY || (rc >= RTAS_EXTENDED_DELAY_MIN &&
1545 rc <= RTAS_EXTENDED_DELAY_MAX));
1546
1547 if (rc < 0)
1548 return rtas_error_rc(rc);
1549
1550 return rc;
1551}
1552
1553/**
1554 * rtas_ibm_suspend_me() - Call ibm,suspend-me to suspend the LPAR.
1555 *
1556 * @fw_status: RTAS call status will be placed here if not NULL.
1557 *
1558 * rtas_ibm_suspend_me() should be called only on a CPU which has
1559 * received H_CONTINUE from the H_JOIN hcall. All other active CPUs
1560 * should be waiting to return from H_JOIN.
1561 *
1562 * rtas_ibm_suspend_me() may suspend execution of the OS
1563 * indefinitely. Callers should take appropriate measures upon return, such as
1564 * resetting watchdog facilities.
1565 *
1566 * Callers may choose to retry this call if @fw_status is
1567 * %RTAS_THREADS_ACTIVE.
1568 *
1569 * Return:
1570 * 0 - The partition has resumed from suspend, possibly after
1571 * migration to a different host.
1572 * -ECANCELED - The operation was aborted.
1573 * -EAGAIN - There were other CPUs not in H_JOIN at the time of the call.
1574 * -EBUSY - Some other condition prevented the suspend from succeeding.
1575 * -EIO - Hardware/platform error.
1576 */
1577int rtas_ibm_suspend_me(int *fw_status)
1578{
1579 int token = rtas_function_token(RTAS_FN_IBM_SUSPEND_ME);
1580 int fwrc;
1581 int ret;
1582
1583 fwrc = rtas_call(token, 0, 1, NULL);
1584
1585 switch (fwrc) {
1586 case 0:
1587 ret = 0;
1588 break;
1589 case RTAS_SUSPEND_ABORTED:
1590 ret = -ECANCELED;
1591 break;
1592 case RTAS_THREADS_ACTIVE:
1593 ret = -EAGAIN;
1594 break;
1595 case RTAS_NOT_SUSPENDABLE:
1596 case RTAS_OUTSTANDING_COPROC:
1597 ret = -EBUSY;
1598 break;
1599 case -1:
1600 default:
1601 ret = -EIO;
1602 break;
1603 }
1604
1605 if (fw_status)
1606 *fw_status = fwrc;
1607
1608 return ret;
1609}
1610
1611void __noreturn rtas_restart(char *cmd)
1612{
1613 if (rtas_flash_term_hook)
1614 rtas_flash_term_hook(SYS_RESTART);
1615 pr_emerg("system-reboot returned %d\n",
1616 rtas_call(rtas_function_token(RTAS_FN_SYSTEM_REBOOT), 0, 1, NULL));
1617 for (;;);
1618}
1619
1620void rtas_power_off(void)
1621{
1622 if (rtas_flash_term_hook)
1623 rtas_flash_term_hook(SYS_POWER_OFF);
1624 /* allow power on only with power button press */
1625 pr_emerg("power-off returned %d\n",
1626 rtas_call(rtas_function_token(RTAS_FN_POWER_OFF), 2, 1, NULL, -1, -1));
1627 for (;;);
1628}
1629
1630void __noreturn rtas_halt(void)
1631{
1632 if (rtas_flash_term_hook)
1633 rtas_flash_term_hook(SYS_HALT);
1634 /* allow power on only with power button press */
1635 pr_emerg("power-off returned %d\n",
1636 rtas_call(rtas_function_token(RTAS_FN_POWER_OFF), 2, 1, NULL, -1, -1));
1637 for (;;);
1638}
1639
1640/* Must be in the RMO region, so we place it here */
1641static char rtas_os_term_buf[2048];
1642static bool ibm_extended_os_term;
1643
1644void rtas_os_term(char *str)
1645{
1646 s32 token = rtas_function_token(RTAS_FN_IBM_OS_TERM);
1647 static struct rtas_args args;
1648 int status;
1649
1650 /*
1651 * Firmware with the ibm,extended-os-term property is guaranteed
1652 * to always return from an ibm,os-term call. Earlier versions without
1653 * this property may terminate the partition which we want to avoid
1654 * since it interferes with panic_timeout.
1655 */
1656
1657 if (token == RTAS_UNKNOWN_SERVICE || !ibm_extended_os_term)
1658 return;
1659
1660 snprintf(buf: rtas_os_term_buf, size: 2048, fmt: "OS panic: %s", str);
1661
1662 /*
1663 * Keep calling as long as RTAS returns a "try again" status,
1664 * but don't use rtas_busy_delay(), which potentially
1665 * schedules.
1666 */
1667 do {
1668 rtas_call_unlocked(&args, token, 1, 1, NULL, __pa(rtas_os_term_buf));
1669 status = be32_to_cpu(args.rets[0]);
1670 } while (rtas_busy_delay_time(status));
1671
1672 if (status != 0)
1673 pr_emerg("ibm,os-term call failed %d\n", status);
1674}
1675
1676/**
1677 * rtas_activate_firmware() - Activate a new version of firmware.
1678 *
1679 * Context: This function may sleep.
1680 *
1681 * Activate a new version of partition firmware. The OS must call this
1682 * after resuming from a partition hibernation or migration in order
1683 * to maintain the ability to perform live firmware updates. It's not
1684 * catastrophic for this method to be absent or to fail; just log the
1685 * condition in that case.
1686 */
1687void rtas_activate_firmware(void)
1688{
1689 int token = rtas_function_token(RTAS_FN_IBM_ACTIVATE_FIRMWARE);
1690 int fwrc;
1691
1692 if (token == RTAS_UNKNOWN_SERVICE) {
1693 pr_notice("ibm,activate-firmware method unavailable\n");
1694 return;
1695 }
1696
1697 mutex_lock(&rtas_ibm_activate_firmware_lock);
1698
1699 do {
1700 fwrc = rtas_call(token, 0, 1, NULL);
1701 } while (rtas_busy_delay(fwrc));
1702
1703 mutex_unlock(lock: &rtas_ibm_activate_firmware_lock);
1704
1705 if (fwrc)
1706 pr_err("ibm,activate-firmware failed (%i)\n", fwrc);
1707}
1708
1709/**
1710 * get_pseries_errorlog() - Find a specific pseries error log in an RTAS
1711 * extended event log.
1712 * @log: RTAS error/event log
1713 * @section_id: two character section identifier
1714 *
1715 * Return: A pointer to the specified errorlog or NULL if not found.
1716 */
1717noinstr struct pseries_errorlog *get_pseries_errorlog(struct rtas_error_log *log,
1718 uint16_t section_id)
1719{
1720 struct rtas_ext_event_log_v6 *ext_log =
1721 (struct rtas_ext_event_log_v6 *)log->buffer;
1722 struct pseries_errorlog *sect;
1723 unsigned char *p, *log_end;
1724 uint32_t ext_log_length = rtas_error_extended_log_length(log);
1725 uint8_t log_format = rtas_ext_event_log_format(ext_log);
1726 uint32_t company_id = rtas_ext_event_company_id(ext_log);
1727
1728 /* Check that we understand the format */
1729 if (ext_log_length < sizeof(struct rtas_ext_event_log_v6) ||
1730 log_format != RTAS_V6EXT_LOG_FORMAT_EVENT_LOG ||
1731 company_id != RTAS_V6EXT_COMPANY_ID_IBM)
1732 return NULL;
1733
1734 log_end = log->buffer + ext_log_length;
1735 p = ext_log->vendor_log;
1736
1737 while (p < log_end) {
1738 sect = (struct pseries_errorlog *)p;
1739 if (pseries_errorlog_id(sect) == section_id)
1740 return sect;
1741 p += pseries_errorlog_length(sect);
1742 }
1743
1744 return NULL;
1745}
1746
1747/*
1748 * The sys_rtas syscall, as originally designed, allows root to pass
1749 * arbitrary physical addresses to RTAS calls. A number of RTAS calls
1750 * can be abused to write to arbitrary memory and do other things that
1751 * are potentially harmful to system integrity, and thus should only
1752 * be used inside the kernel and not exposed to userspace.
1753 *
1754 * All known legitimate users of the sys_rtas syscall will only ever
1755 * pass addresses that fall within the RMO buffer, and use a known
1756 * subset of RTAS calls.
1757 *
1758 * Accordingly, we filter RTAS requests to check that the call is
1759 * permitted, and that provided pointers fall within the RMO buffer.
1760 * If a function is allowed to be invoked via the syscall, then its
1761 * entry in the rtas_functions table points to a rtas_filter that
1762 * describes its constraints, with the indexes of the parameters which
1763 * are expected to contain addresses and sizes of buffers allocated
1764 * inside the RMO buffer.
1765 */
1766
1767static bool in_rmo_buf(u32 base, u32 end)
1768{
1769 return base >= rtas_rmo_buf &&
1770 base < (rtas_rmo_buf + RTAS_USER_REGION_SIZE) &&
1771 base <= end &&
1772 end >= rtas_rmo_buf &&
1773 end < (rtas_rmo_buf + RTAS_USER_REGION_SIZE);
1774}
1775
1776static bool block_rtas_call(const struct rtas_function *func, int nargs,
1777 struct rtas_args *args)
1778{
1779 const struct rtas_filter *f;
1780 const bool is_platform_dump =
1781 func == &rtas_function_table[RTAS_FNIDX__IBM_PLATFORM_DUMP];
1782 const bool is_config_conn =
1783 func == &rtas_function_table[RTAS_FNIDX__IBM_CONFIGURE_CONNECTOR];
1784 u32 base, size, end;
1785
1786 /*
1787 * Only functions with filters attached are allowed.
1788 */
1789 f = func->filter;
1790 if (!f)
1791 goto err;
1792 /*
1793 * And some functions aren't allowed on LE.
1794 */
1795 if (IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN) && func->banned_for_syscall_on_le)
1796 goto err;
1797
1798 if (f->buf_idx1 != -1) {
1799 base = be32_to_cpu(args->args[f->buf_idx1]);
1800 if (f->size_idx1 != -1)
1801 size = be32_to_cpu(args->args[f->size_idx1]);
1802 else if (f->fixed_size)
1803 size = f->fixed_size;
1804 else
1805 size = 1;
1806
1807 end = base + size - 1;
1808
1809 /*
1810 * Special case for ibm,platform-dump - NULL buffer
1811 * address is used to indicate end of dump processing
1812 */
1813 if (is_platform_dump && base == 0)
1814 return false;
1815
1816 if (!in_rmo_buf(base, end))
1817 goto err;
1818 }
1819
1820 if (f->buf_idx2 != -1) {
1821 base = be32_to_cpu(args->args[f->buf_idx2]);
1822 if (f->size_idx2 != -1)
1823 size = be32_to_cpu(args->args[f->size_idx2]);
1824 else if (f->fixed_size)
1825 size = f->fixed_size;
1826 else
1827 size = 1;
1828 end = base + size - 1;
1829
1830 /*
1831 * Special case for ibm,configure-connector where the
1832 * address can be 0
1833 */
1834 if (is_config_conn && base == 0)
1835 return false;
1836
1837 if (!in_rmo_buf(base, end))
1838 goto err;
1839 }
1840
1841 return false;
1842err:
1843 pr_err_ratelimited("sys_rtas: RTAS call blocked - exploit attempt?\n");
1844 pr_err_ratelimited("sys_rtas: %s nargs=%d (called by %s)\n",
1845 func->name, nargs, current->comm);
1846 return true;
1847}
1848
1849/* We assume to be passed big endian arguments */
1850SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs)
1851{
1852 const struct rtas_function *func;
1853 struct pin_cookie cookie;
1854 struct rtas_args args;
1855 unsigned long flags;
1856 char *buff_copy, *errbuf = NULL;
1857 int nargs, nret, token;
1858
1859 if (!capable(CAP_SYS_ADMIN))
1860 return -EPERM;
1861
1862 if (!rtas.entry)
1863 return -EINVAL;
1864
1865 if (copy_from_user(to: &args, from: uargs, n: 3 * sizeof(u32)) != 0)
1866 return -EFAULT;
1867
1868 nargs = be32_to_cpu(args.nargs);
1869 nret = be32_to_cpu(args.nret);
1870 token = be32_to_cpu(args.token);
1871
1872 if (nargs >= ARRAY_SIZE(args.args)
1873 || nret > ARRAY_SIZE(args.args)
1874 || nargs + nret > ARRAY_SIZE(args.args))
1875 return -EINVAL;
1876
1877 nargs = array_index_nospec(nargs, ARRAY_SIZE(args.args));
1878 nret = array_index_nospec(nret, ARRAY_SIZE(args.args) - nargs);
1879
1880 /* Copy in args. */
1881 if (copy_from_user(args.args, uargs->args,
1882 nargs * sizeof(rtas_arg_t)) != 0)
1883 return -EFAULT;
1884
1885 /*
1886 * If this token doesn't correspond to a function the kernel
1887 * understands, you're not allowed to call it.
1888 */
1889 func = rtas_token_to_function_untrusted(token);
1890 if (!func)
1891 return -EINVAL;
1892
1893 args.rets = &args.args[nargs];
1894 memset(args.rets, 0, nret * sizeof(rtas_arg_t));
1895
1896 if (block_rtas_call(func, nargs, args: &args))
1897 return -EINVAL;
1898
1899 if (token_is_restricted_errinjct(token)) {
1900 int err;
1901
1902 err = security_locked_down(what: LOCKDOWN_RTAS_ERROR_INJECTION);
1903 if (err)
1904 return err;
1905 }
1906
1907 /* Need to handle ibm,suspend_me call specially */
1908 if (token == rtas_function_token(RTAS_FN_IBM_SUSPEND_ME)) {
1909
1910 /*
1911 * rtas_ibm_suspend_me assumes the streamid handle is in cpu
1912 * endian, or at least the hcall within it requires it.
1913 */
1914 int rc = 0;
1915 u64 handle = ((u64)be32_to_cpu(args.args[0]) << 32)
1916 | be32_to_cpu(args.args[1]);
1917 rc = rtas_syscall_dispatch_ibm_suspend_me(handle);
1918 if (rc == -EAGAIN)
1919 args.rets[0] = cpu_to_be32(RTAS_NOT_SUSPENDABLE);
1920 else if (rc == -EIO)
1921 args.rets[0] = cpu_to_be32(-1);
1922 else if (rc)
1923 return rc;
1924 goto copy_return;
1925 }
1926
1927 buff_copy = get_errorlog_buffer();
1928
1929 /*
1930 * If this function has a mutex assigned to it, we must
1931 * acquire it to avoid interleaving with any kernel-based uses
1932 * of the same function. Kernel-based sequences acquire the
1933 * appropriate mutex explicitly.
1934 */
1935 if (func->lock)
1936 mutex_lock(func->lock);
1937
1938 raw_spin_lock_irqsave(&rtas_lock, flags);
1939 cookie = lockdep_pin_lock(&rtas_lock);
1940
1941 rtas_args = args;
1942 do_enter_rtas(args: &rtas_args);
1943 args = rtas_args;
1944
1945 /* A -1 return code indicates that the last command couldn't
1946 be completed due to a hardware error. */
1947 if (be32_to_cpu(args.rets[0]) == -1)
1948 errbuf = __fetch_rtas_last_error(buff_copy);
1949
1950 lockdep_unpin_lock(&rtas_lock, cookie);
1951 raw_spin_unlock_irqrestore(&rtas_lock, flags);
1952
1953 if (func->lock)
1954 mutex_unlock(lock: func->lock);
1955
1956 if (buff_copy) {
1957 if (errbuf)
1958 log_error(errbuf, ERR_TYPE_RTAS_LOG, 0);
1959 kfree(objp: buff_copy);
1960 }
1961
1962 copy_return:
1963 /* Copy out args. */
1964 if (copy_to_user(uargs->args + nargs,
1965 args.args + nargs,
1966 nret * sizeof(rtas_arg_t)) != 0)
1967 return -EFAULT;
1968
1969 return 0;
1970}
1971
1972static void __init rtas_function_table_init(void)
1973{
1974 struct property *prop;
1975
1976 for (size_t i = 0; i < ARRAY_SIZE(rtas_function_table); ++i) {
1977 struct rtas_function *curr = &rtas_function_table[i];
1978 struct rtas_function *prior;
1979 int cmp;
1980
1981 curr->token = RTAS_UNKNOWN_SERVICE;
1982
1983 if (i == 0)
1984 continue;
1985 /*
1986 * Ensure table is sorted correctly for binary search
1987 * on function names.
1988 */
1989 prior = &rtas_function_table[i - 1];
1990
1991 cmp = strcmp(prior->name, curr->name);
1992 if (cmp < 0)
1993 continue;
1994
1995 if (cmp == 0) {
1996 pr_err("'%s' has duplicate function table entries\n",
1997 curr->name);
1998 } else {
1999 pr_err("function table unsorted: '%s' wrongly precedes '%s'\n",
2000 prior->name, curr->name);
2001 }
2002 }
2003
2004 for_each_property_of_node(rtas.dev, prop) {
2005 struct rtas_function *func;
2006
2007 if (prop->length != sizeof(u32))
2008 continue;
2009
2010 func = __rtas_name_to_function(name: prop->name);
2011 if (!func)
2012 continue;
2013
2014 func->token = be32_to_cpup(p: (__be32 *)prop->value);
2015
2016 pr_debug("function %s has token %u\n", func->name, func->token);
2017 }
2018}
2019
2020/*
2021 * Call early during boot, before mem init, to retrieve the RTAS
2022 * information from the device-tree and allocate the RMO buffer for userland
2023 * accesses.
2024 */
2025void __init rtas_initialize(void)
2026{
2027 unsigned long rtas_region = RTAS_INSTANTIATE_MAX;
2028 u32 base, size, entry;
2029 int no_base, no_size, no_entry;
2030
2031 /* Get RTAS dev node and fill up our "rtas" structure with infos
2032 * about it.
2033 */
2034 rtas.dev = of_find_node_by_name(NULL, name: "rtas");
2035 if (!rtas.dev)
2036 return;
2037
2038 no_base = of_property_read_u32(np: rtas.dev, propname: "linux,rtas-base", out_value: &base);
2039 no_size = of_property_read_u32(np: rtas.dev, propname: "rtas-size", out_value: &size);
2040 if (no_base || no_size) {
2041 of_node_put(node: rtas.dev);
2042 rtas.dev = NULL;
2043 return;
2044 }
2045
2046 rtas.base = base;
2047 rtas.size = size;
2048 no_entry = of_property_read_u32(np: rtas.dev, propname: "linux,rtas-entry", out_value: &entry);
2049 rtas.entry = no_entry ? rtas.base : entry;
2050
2051 init_error_log_max();
2052
2053 /* Must be called before any function token lookups */
2054 rtas_function_table_init();
2055
2056 /*
2057 * Discover this now to avoid a device tree lookup in the
2058 * panic path.
2059 */
2060 ibm_extended_os_term = of_property_read_bool(np: rtas.dev, propname: "ibm,extended-os-term");
2061
2062 /* If RTAS was found, allocate the RMO buffer for it and look for
2063 * the stop-self token if any
2064 */
2065#ifdef CONFIG_PPC64
2066 if (firmware_has_feature(FW_FEATURE_LPAR))
2067 rtas_region = min(ppc64_rma_size, RTAS_INSTANTIATE_MAX);
2068#endif
2069 rtas_rmo_buf = memblock_phys_alloc_range(RTAS_USER_REGION_SIZE, PAGE_SIZE,
2070 0, rtas_region);
2071 if (!rtas_rmo_buf)
2072 panic(fmt: "ERROR: RTAS: Failed to allocate %lx bytes below %pa\n",
2073 PAGE_SIZE, &rtas_region);
2074
2075 rtas_work_area_reserve_arena(rtas_region);
2076}
2077
2078int __init early_init_dt_scan_rtas(unsigned long node,
2079 const char *uname, int depth, void *data)
2080{
2081 const u32 *basep, *entryp, *sizep;
2082
2083 if (depth != 1 || strcmp(uname, "rtas") != 0)
2084 return 0;
2085
2086 basep = of_get_flat_dt_prop(node, name: "linux,rtas-base", NULL);
2087 entryp = of_get_flat_dt_prop(node, name: "linux,rtas-entry", NULL);
2088 sizep = of_get_flat_dt_prop(node, name: "rtas-size", NULL);
2089
2090#ifdef CONFIG_PPC64
2091 /* need this feature to decide the crashkernel offset */
2092 if (of_get_flat_dt_prop(node, "ibm,hypertas-functions", NULL))
2093 powerpc_firmware_features |= FW_FEATURE_LPAR;
2094#endif
2095
2096 if (basep && entryp && sizep) {
2097 rtas.base = *basep;
2098 rtas.entry = *entryp;
2099 rtas.size = *sizep;
2100 }
2101
2102 /* break now */
2103 return 1;
2104}
2105
2106static DEFINE_RAW_SPINLOCK(timebase_lock);
2107static u64 timebase = 0;
2108
2109void rtas_give_timebase(void)
2110{
2111 unsigned long flags;
2112
2113 raw_spin_lock_irqsave(&timebase_lock, flags);
2114 hard_irq_disable();
2115 rtas_call(rtas_function_token(RTAS_FN_FREEZE_TIME_BASE), 0, 1, NULL);
2116 timebase = get_tb();
2117 raw_spin_unlock(&timebase_lock);
2118
2119 while (timebase)
2120 barrier();
2121 rtas_call(rtas_function_token(RTAS_FN_THAW_TIME_BASE), 0, 1, NULL);
2122 local_irq_restore(flags);
2123}
2124
2125void rtas_take_timebase(void)
2126{
2127 while (!timebase)
2128 barrier();
2129 raw_spin_lock(&timebase_lock);
2130 set_tb(timebase >> 32, timebase & 0xffffffff);
2131 timebase = 0;
2132 raw_spin_unlock(&timebase_lock);
2133}
2134

source code of linux/arch/powerpc/kernel/rtas.c