xref: /linux/arch/powerpc/kernel/rtas.c (revision fcb3ad4366b9c810cbb9da34c076a9a52d8aa1e0)
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 
48 struct 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  */
83 struct 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  */
94 static DEFINE_MUTEX(rtas_ibm_activate_firmware_lock);
95 static DEFINE_MUTEX(rtas_ibm_get_dynamic_sensor_state_lock);
96 static DEFINE_MUTEX(rtas_ibm_get_indices_lock);
97 static DEFINE_MUTEX(rtas_ibm_lpar_perftools_lock);
98 static DEFINE_MUTEX(rtas_ibm_physical_attestation_lock);
99 static DEFINE_MUTEX(rtas_ibm_set_dynamic_indicator_lock);
100 DEFINE_MUTEX(rtas_ibm_get_vpd_lock);
101 
102 static struct rtas_function rtas_function_table[] __ro_after_init = {
103 	[RTAS_FNIDX__CHECK_EXCEPTION] = {
104 		.name = "check-exception",
105 	},
106 	[RTAS_FNIDX__DISPLAY_CHARACTER] = {
107 		.name = "display-character",
108 		.filter = &(const struct rtas_filter) {
109 			.buf_idx1 = -1, .size_idx1 = -1,
110 			.buf_idx2 = -1, .size_idx2 = -1,
111 		},
112 	},
113 	[RTAS_FNIDX__EVENT_SCAN] = {
114 		.name = "event-scan",
115 	},
116 	[RTAS_FNIDX__FREEZE_TIME_BASE] = {
117 		.name = "freeze-time-base",
118 	},
119 	[RTAS_FNIDX__GET_POWER_LEVEL] = {
120 		.name = "get-power-level",
121 		.filter = &(const struct rtas_filter) {
122 			.buf_idx1 = -1, .size_idx1 = -1,
123 			.buf_idx2 = -1, .size_idx2 = -1,
124 		},
125 	},
126 	[RTAS_FNIDX__GET_SENSOR_STATE] = {
127 		.name = "get-sensor-state",
128 		.filter = &(const struct rtas_filter) {
129 			.buf_idx1 = -1, .size_idx1 = -1,
130 			.buf_idx2 = -1, .size_idx2 = -1,
131 		},
132 	},
133 	[RTAS_FNIDX__GET_TERM_CHAR] = {
134 		.name = "get-term-char",
135 	},
136 	[RTAS_FNIDX__GET_TIME_OF_DAY] = {
137 		.name = "get-time-of-day",
138 		.filter = &(const struct rtas_filter) {
139 			.buf_idx1 = -1, .size_idx1 = -1,
140 			.buf_idx2 = -1, .size_idx2 = -1,
141 		},
142 	},
143 	[RTAS_FNIDX__IBM_ACTIVATE_FIRMWARE] = {
144 		.name = "ibm,activate-firmware",
145 		.filter = &(const struct rtas_filter) {
146 			.buf_idx1 = -1, .size_idx1 = -1,
147 			.buf_idx2 = -1, .size_idx2 = -1,
148 		},
149 		/*
150 		 * PAPR+ as of v2.13 doesn't explicitly impose any
151 		 * restriction, but this typically requires multiple
152 		 * calls before success, and there's no reason to
153 		 * allow sequences to interleave.
154 		 */
155 		.lock = &rtas_ibm_activate_firmware_lock,
156 	},
157 	[RTAS_FNIDX__IBM_CBE_START_PTCAL] = {
158 		.name = "ibm,cbe-start-ptcal",
159 	},
160 	[RTAS_FNIDX__IBM_CBE_STOP_PTCAL] = {
161 		.name = "ibm,cbe-stop-ptcal",
162 	},
163 	[RTAS_FNIDX__IBM_CHANGE_MSI] = {
164 		.name = "ibm,change-msi",
165 	},
166 	[RTAS_FNIDX__IBM_CLOSE_ERRINJCT] = {
167 		.name = "ibm,close-errinjct",
168 		.filter = &(const struct rtas_filter) {
169 			.buf_idx1 = -1, .size_idx1 = -1,
170 			.buf_idx2 = -1, .size_idx2 = -1,
171 		},
172 	},
173 	[RTAS_FNIDX__IBM_CONFIGURE_BRIDGE] = {
174 		.name = "ibm,configure-bridge",
175 	},
176 	[RTAS_FNIDX__IBM_CONFIGURE_CONNECTOR] = {
177 		.name = "ibm,configure-connector",
178 		.filter = &(const struct rtas_filter) {
179 			.buf_idx1 = 0, .size_idx1 = -1,
180 			.buf_idx2 = 1, .size_idx2 = -1,
181 			.fixed_size = 4096,
182 		},
183 	},
184 	[RTAS_FNIDX__IBM_CONFIGURE_KERNEL_DUMP] = {
185 		.name = "ibm,configure-kernel-dump",
186 	},
187 	[RTAS_FNIDX__IBM_CONFIGURE_PE] = {
188 		.name = "ibm,configure-pe",
189 	},
190 	[RTAS_FNIDX__IBM_CREATE_PE_DMA_WINDOW] = {
191 		.name = "ibm,create-pe-dma-window",
192 	},
193 	[RTAS_FNIDX__IBM_DISPLAY_MESSAGE] = {
194 		.name = "ibm,display-message",
195 		.filter = &(const struct rtas_filter) {
196 			.buf_idx1 = 0, .size_idx1 = -1,
197 			.buf_idx2 = -1, .size_idx2 = -1,
198 		},
199 	},
200 	[RTAS_FNIDX__IBM_ERRINJCT] = {
201 		.name = "ibm,errinjct",
202 		.filter = &(const struct rtas_filter) {
203 			.buf_idx1 = 2, .size_idx1 = -1,
204 			.buf_idx2 = -1, .size_idx2 = -1,
205 			.fixed_size = 1024,
206 		},
207 	},
208 	[RTAS_FNIDX__IBM_EXTI2C] = {
209 		.name = "ibm,exti2c",
210 	},
211 	[RTAS_FNIDX__IBM_GET_CONFIG_ADDR_INFO] = {
212 		.name = "ibm,get-config-addr-info",
213 	},
214 	[RTAS_FNIDX__IBM_GET_CONFIG_ADDR_INFO2] = {
215 		.name = "ibm,get-config-addr-info2",
216 		.filter = &(const struct rtas_filter) {
217 			.buf_idx1 = -1, .size_idx1 = -1,
218 			.buf_idx2 = -1, .size_idx2 = -1,
219 		},
220 	},
221 	[RTAS_FNIDX__IBM_GET_DYNAMIC_SENSOR_STATE] = {
222 		.name = "ibm,get-dynamic-sensor-state",
223 		.filter = &(const struct rtas_filter) {
224 			.buf_idx1 = 1, .size_idx1 = -1,
225 			.buf_idx2 = -1, .size_idx2 = -1,
226 		},
227 		/*
228 		 * PAPR+ v2.13 R1–7.3.19–3 is explicit that the OS
229 		 * must not call ibm,get-dynamic-sensor-state with
230 		 * different inputs until a non-retry status has been
231 		 * returned.
232 		 */
233 		.lock = &rtas_ibm_get_dynamic_sensor_state_lock,
234 	},
235 	[RTAS_FNIDX__IBM_GET_INDICES] = {
236 		.name = "ibm,get-indices",
237 		.filter = &(const struct rtas_filter) {
238 			.buf_idx1 = 2, .size_idx1 = 3,
239 			.buf_idx2 = -1, .size_idx2 = -1,
240 		},
241 		/*
242 		 * PAPR+ v2.13 R1–7.3.17–2 says that the OS must not
243 		 * interleave ibm,get-indices call sequences with
244 		 * different inputs.
245 		 */
246 		.lock = &rtas_ibm_get_indices_lock,
247 	},
248 	[RTAS_FNIDX__IBM_GET_RIO_TOPOLOGY] = {
249 		.name = "ibm,get-rio-topology",
250 	},
251 	[RTAS_FNIDX__IBM_GET_SYSTEM_PARAMETER] = {
252 		.name = "ibm,get-system-parameter",
253 		.filter = &(const struct rtas_filter) {
254 			.buf_idx1 = 1, .size_idx1 = 2,
255 			.buf_idx2 = -1, .size_idx2 = -1,
256 		},
257 	},
258 	[RTAS_FNIDX__IBM_GET_VPD] = {
259 		.name = "ibm,get-vpd",
260 		.filter = &(const struct rtas_filter) {
261 			.buf_idx1 = 0, .size_idx1 = -1,
262 			.buf_idx2 = 1, .size_idx2 = 2,
263 		},
264 		/*
265 		 * PAPR+ v2.13 R1–7.3.20–4 indicates that sequences
266 		 * should not be allowed to interleave.
267 		 */
268 		.lock = &rtas_ibm_get_vpd_lock,
269 	},
270 	[RTAS_FNIDX__IBM_GET_XIVE] = {
271 		.name = "ibm,get-xive",
272 	},
273 	[RTAS_FNIDX__IBM_INT_OFF] = {
274 		.name = "ibm,int-off",
275 	},
276 	[RTAS_FNIDX__IBM_INT_ON] = {
277 		.name = "ibm,int-on",
278 	},
279 	[RTAS_FNIDX__IBM_IO_QUIESCE_ACK] = {
280 		.name = "ibm,io-quiesce-ack",
281 	},
282 	[RTAS_FNIDX__IBM_LPAR_PERFTOOLS] = {
283 		.name = "ibm,lpar-perftools",
284 		.filter = &(const struct rtas_filter) {
285 			.buf_idx1 = 2, .size_idx1 = 3,
286 			.buf_idx2 = -1, .size_idx2 = -1,
287 		},
288 		/*
289 		 * PAPR+ v2.13 R1–7.3.26–6 says the OS should allow
290 		 * only one call sequence in progress at a time.
291 		 */
292 		.lock = &rtas_ibm_lpar_perftools_lock,
293 	},
294 	[RTAS_FNIDX__IBM_MANAGE_FLASH_IMAGE] = {
295 		.name = "ibm,manage-flash-image",
296 	},
297 	[RTAS_FNIDX__IBM_MANAGE_STORAGE_PRESERVATION] = {
298 		.name = "ibm,manage-storage-preservation",
299 	},
300 	[RTAS_FNIDX__IBM_NMI_INTERLOCK] = {
301 		.name = "ibm,nmi-interlock",
302 	},
303 	[RTAS_FNIDX__IBM_NMI_REGISTER] = {
304 		.name = "ibm,nmi-register",
305 	},
306 	[RTAS_FNIDX__IBM_OPEN_ERRINJCT] = {
307 		.name = "ibm,open-errinjct",
308 		.filter = &(const struct rtas_filter) {
309 			.buf_idx1 = -1, .size_idx1 = -1,
310 			.buf_idx2 = -1, .size_idx2 = -1,
311 		},
312 	},
313 	[RTAS_FNIDX__IBM_OPEN_SRIOV_ALLOW_UNFREEZE] = {
314 		.name = "ibm,open-sriov-allow-unfreeze",
315 	},
316 	[RTAS_FNIDX__IBM_OPEN_SRIOV_MAP_PE_NUMBER] = {
317 		.name = "ibm,open-sriov-map-pe-number",
318 	},
319 	[RTAS_FNIDX__IBM_OS_TERM] = {
320 		.name = "ibm,os-term",
321 	},
322 	[RTAS_FNIDX__IBM_PARTNER_CONTROL] = {
323 		.name = "ibm,partner-control",
324 	},
325 	[RTAS_FNIDX__IBM_PHYSICAL_ATTESTATION] = {
326 		.name = "ibm,physical-attestation",
327 		.filter = &(const struct rtas_filter) {
328 			.buf_idx1 = 0, .size_idx1 = 1,
329 			.buf_idx2 = -1, .size_idx2 = -1,
330 		},
331 		/*
332 		 * This follows a sequence-based pattern similar to
333 		 * ibm,get-vpd et al. Since PAPR+ restricts
334 		 * interleaving call sequences for other functions of
335 		 * this style, assume the restriction applies here,
336 		 * even though it's not explicit in the spec.
337 		 */
338 		.lock = &rtas_ibm_physical_attestation_lock,
339 	},
340 	[RTAS_FNIDX__IBM_PLATFORM_DUMP] = {
341 		.name = "ibm,platform-dump",
342 		.filter = &(const struct rtas_filter) {
343 			.buf_idx1 = 4, .size_idx1 = 5,
344 			.buf_idx2 = -1, .size_idx2 = -1,
345 		},
346 		/*
347 		 * PAPR+ v2.13 7.3.3.4.1 indicates that concurrent
348 		 * sequences of ibm,platform-dump are allowed if they
349 		 * are operating on different dump tags. So leave the
350 		 * lock pointer unset for now. This may need
351 		 * reconsideration if kernel-internal users appear.
352 		 */
353 	},
354 	[RTAS_FNIDX__IBM_POWER_OFF_UPS] = {
355 		.name = "ibm,power-off-ups",
356 	},
357 	[RTAS_FNIDX__IBM_QUERY_INTERRUPT_SOURCE_NUMBER] = {
358 		.name = "ibm,query-interrupt-source-number",
359 	},
360 	[RTAS_FNIDX__IBM_QUERY_PE_DMA_WINDOW] = {
361 		.name = "ibm,query-pe-dma-window",
362 	},
363 	[RTAS_FNIDX__IBM_READ_PCI_CONFIG] = {
364 		.name = "ibm,read-pci-config",
365 	},
366 	[RTAS_FNIDX__IBM_READ_SLOT_RESET_STATE] = {
367 		.name = "ibm,read-slot-reset-state",
368 		.filter = &(const struct rtas_filter) {
369 			.buf_idx1 = -1, .size_idx1 = -1,
370 			.buf_idx2 = -1, .size_idx2 = -1,
371 		},
372 	},
373 	[RTAS_FNIDX__IBM_READ_SLOT_RESET_STATE2] = {
374 		.name = "ibm,read-slot-reset-state2",
375 	},
376 	[RTAS_FNIDX__IBM_REMOVE_PE_DMA_WINDOW] = {
377 		.name = "ibm,remove-pe-dma-window",
378 	},
379 	[RTAS_FNIDX__IBM_RESET_PE_DMA_WINDOW] = {
380 		/*
381 		 * Note: PAPR+ v2.13 7.3.31.4.1 spells this as
382 		 * "ibm,reset-pe-dma-windows" (plural), but RTAS
383 		 * implementations use the singular form in practice.
384 		 */
385 		.name = "ibm,reset-pe-dma-window",
386 	},
387 	[RTAS_FNIDX__IBM_SCAN_LOG_DUMP] = {
388 		.name = "ibm,scan-log-dump",
389 		.filter = &(const struct rtas_filter) {
390 			.buf_idx1 = 0, .size_idx1 = 1,
391 			.buf_idx2 = -1, .size_idx2 = -1,
392 		},
393 	},
394 	[RTAS_FNIDX__IBM_SET_DYNAMIC_INDICATOR] = {
395 		.name = "ibm,set-dynamic-indicator",
396 		.filter = &(const struct rtas_filter) {
397 			.buf_idx1 = 2, .size_idx1 = -1,
398 			.buf_idx2 = -1, .size_idx2 = -1,
399 		},
400 		/*
401 		 * PAPR+ v2.13 R1–7.3.18–3 says the OS must not call
402 		 * this function with different inputs until a
403 		 * non-retry status has been returned.
404 		 */
405 		.lock = &rtas_ibm_set_dynamic_indicator_lock,
406 	},
407 	[RTAS_FNIDX__IBM_SET_EEH_OPTION] = {
408 		.name = "ibm,set-eeh-option",
409 		.filter = &(const struct rtas_filter) {
410 			.buf_idx1 = -1, .size_idx1 = -1,
411 			.buf_idx2 = -1, .size_idx2 = -1,
412 		},
413 	},
414 	[RTAS_FNIDX__IBM_SET_SLOT_RESET] = {
415 		.name = "ibm,set-slot-reset",
416 	},
417 	[RTAS_FNIDX__IBM_SET_SYSTEM_PARAMETER] = {
418 		.name = "ibm,set-system-parameter",
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__IBM_SET_XIVE] = {
425 		.name = "ibm,set-xive",
426 	},
427 	[RTAS_FNIDX__IBM_SLOT_ERROR_DETAIL] = {
428 		.name = "ibm,slot-error-detail",
429 	},
430 	[RTAS_FNIDX__IBM_SUSPEND_ME] = {
431 		.name = "ibm,suspend-me",
432 		.banned_for_syscall_on_le = true,
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_TUNE_DMA_PARMS] = {
439 		.name = "ibm,tune-dma-parms",
440 	},
441 	[RTAS_FNIDX__IBM_UPDATE_FLASH_64_AND_REBOOT] = {
442 		.name = "ibm,update-flash-64-and-reboot",
443 	},
444 	[RTAS_FNIDX__IBM_UPDATE_NODES] = {
445 		.name = "ibm,update-nodes",
446 		.banned_for_syscall_on_le = true,
447 		.filter = &(const struct rtas_filter) {
448 			.buf_idx1 = 0, .size_idx1 = -1,
449 			.buf_idx2 = -1, .size_idx2 = -1,
450 			.fixed_size = 4096,
451 		},
452 	},
453 	[RTAS_FNIDX__IBM_UPDATE_PROPERTIES] = {
454 		.name = "ibm,update-properties",
455 		.banned_for_syscall_on_le = true,
456 		.filter = &(const struct rtas_filter) {
457 			.buf_idx1 = 0, .size_idx1 = -1,
458 			.buf_idx2 = -1, .size_idx2 = -1,
459 			.fixed_size = 4096,
460 		},
461 	},
462 	[RTAS_FNIDX__IBM_VALIDATE_FLASH_IMAGE] = {
463 		.name = "ibm,validate-flash-image",
464 	},
465 	[RTAS_FNIDX__IBM_WRITE_PCI_CONFIG] = {
466 		.name = "ibm,write-pci-config",
467 	},
468 	[RTAS_FNIDX__NVRAM_FETCH] = {
469 		.name = "nvram-fetch",
470 	},
471 	[RTAS_FNIDX__NVRAM_STORE] = {
472 		.name = "nvram-store",
473 	},
474 	[RTAS_FNIDX__POWER_OFF] = {
475 		.name = "power-off",
476 	},
477 	[RTAS_FNIDX__PUT_TERM_CHAR] = {
478 		.name = "put-term-char",
479 	},
480 	[RTAS_FNIDX__QUERY_CPU_STOPPED_STATE] = {
481 		.name = "query-cpu-stopped-state",
482 	},
483 	[RTAS_FNIDX__READ_PCI_CONFIG] = {
484 		.name = "read-pci-config",
485 	},
486 	[RTAS_FNIDX__RTAS_LAST_ERROR] = {
487 		.name = "rtas-last-error",
488 	},
489 	[RTAS_FNIDX__SET_INDICATOR] = {
490 		.name = "set-indicator",
491 		.filter = &(const struct rtas_filter) {
492 			.buf_idx1 = -1, .size_idx1 = -1,
493 			.buf_idx2 = -1, .size_idx2 = -1,
494 		},
495 	},
496 	[RTAS_FNIDX__SET_POWER_LEVEL] = {
497 		.name = "set-power-level",
498 		.filter = &(const struct rtas_filter) {
499 			.buf_idx1 = -1, .size_idx1 = -1,
500 			.buf_idx2 = -1, .size_idx2 = -1,
501 		},
502 	},
503 	[RTAS_FNIDX__SET_TIME_FOR_POWER_ON] = {
504 		.name = "set-time-for-power-on",
505 		.filter = &(const struct rtas_filter) {
506 			.buf_idx1 = -1, .size_idx1 = -1,
507 			.buf_idx2 = -1, .size_idx2 = -1,
508 		},
509 	},
510 	[RTAS_FNIDX__SET_TIME_OF_DAY] = {
511 		.name = "set-time-of-day",
512 		.filter = &(const struct rtas_filter) {
513 			.buf_idx1 = -1, .size_idx1 = -1,
514 			.buf_idx2 = -1, .size_idx2 = -1,
515 		},
516 	},
517 	[RTAS_FNIDX__START_CPU] = {
518 		.name = "start-cpu",
519 	},
520 	[RTAS_FNIDX__STOP_SELF] = {
521 		.name = "stop-self",
522 	},
523 	[RTAS_FNIDX__SYSTEM_REBOOT] = {
524 		.name = "system-reboot",
525 	},
526 	[RTAS_FNIDX__THAW_TIME_BASE] = {
527 		.name = "thaw-time-base",
528 	},
529 	[RTAS_FNIDX__WRITE_PCI_CONFIG] = {
530 		.name = "write-pci-config",
531 	},
532 };
533 
534 #define for_each_rtas_function(funcp)                                       \
535 	for (funcp = &rtas_function_table[0];                               \
536 	     funcp < &rtas_function_table[ARRAY_SIZE(rtas_function_table)]; \
537 	     ++funcp)
538 
539 /*
540  * Nearly all RTAS calls need to be serialized. All uses of the
541  * default rtas_args block must hold rtas_lock.
542  *
543  * Exceptions to the RTAS serialization requirement (e.g. stop-self)
544  * must use a separate rtas_args structure.
545  */
546 static DEFINE_RAW_SPINLOCK(rtas_lock);
547 static struct rtas_args rtas_args;
548 
549 /**
550  * rtas_function_token() - RTAS function token lookup.
551  * @handle: Function handle, e.g. RTAS_FN_EVENT_SCAN.
552  *
553  * Context: Any context.
554  * Return: the token value for the function if implemented by this platform,
555  *         otherwise RTAS_UNKNOWN_SERVICE.
556  */
557 s32 rtas_function_token(const rtas_fn_handle_t handle)
558 {
559 	const size_t index = handle.index;
560 	const bool out_of_bounds = index >= ARRAY_SIZE(rtas_function_table);
561 
562 	if (WARN_ONCE(out_of_bounds, "invalid function index %zu", index))
563 		return RTAS_UNKNOWN_SERVICE;
564 	/*
565 	 * Various drivers attempt token lookups on non-RTAS
566 	 * platforms.
567 	 */
568 	if (!rtas.dev)
569 		return RTAS_UNKNOWN_SERVICE;
570 
571 	return rtas_function_table[index].token;
572 }
573 EXPORT_SYMBOL_GPL(rtas_function_token);
574 
575 static int rtas_function_cmp(const void *a, const void *b)
576 {
577 	const struct rtas_function *f1 = a;
578 	const struct rtas_function *f2 = b;
579 
580 	return strcmp(f1->name, f2->name);
581 }
582 
583 /*
584  * Boot-time initialization of the function table needs the lookup to
585  * return a non-const-qualified object. Use rtas_name_to_function()
586  * in all other contexts.
587  */
588 static struct rtas_function *__rtas_name_to_function(const char *name)
589 {
590 	const struct rtas_function key = {
591 		.name = name,
592 	};
593 	struct rtas_function *found;
594 
595 	found = bsearch(&key, rtas_function_table, ARRAY_SIZE(rtas_function_table),
596 			sizeof(rtas_function_table[0]), rtas_function_cmp);
597 
598 	return found;
599 }
600 
601 static const struct rtas_function *rtas_name_to_function(const char *name)
602 {
603 	return __rtas_name_to_function(name);
604 }
605 
606 static DEFINE_XARRAY(rtas_token_to_function_xarray);
607 
608 static int __init rtas_token_to_function_xarray_init(void)
609 {
610 	const struct rtas_function *func;
611 	int err = 0;
612 
613 	for_each_rtas_function(func) {
614 		const s32 token = func->token;
615 
616 		if (token == RTAS_UNKNOWN_SERVICE)
617 			continue;
618 
619 		err = xa_err(xa_store(&rtas_token_to_function_xarray,
620 				      token, (void *)func, GFP_KERNEL));
621 		if (err)
622 			break;
623 	}
624 
625 	return err;
626 }
627 arch_initcall(rtas_token_to_function_xarray_init);
628 
629 /*
630  * For use by sys_rtas(), where the token value is provided by user
631  * space and we don't want to warn on failed lookups.
632  */
633 static const struct rtas_function *rtas_token_to_function_untrusted(s32 token)
634 {
635 	return xa_load(&rtas_token_to_function_xarray, token);
636 }
637 
638 /*
639  * Reverse lookup for deriving the function descriptor from a
640  * known-good token value in contexts where the former is not already
641  * available. @token must be valid, e.g. derived from the result of a
642  * prior lookup against the function table.
643  */
644 static const struct rtas_function *rtas_token_to_function(s32 token)
645 {
646 	const struct rtas_function *func;
647 
648 	if (WARN_ONCE(token < 0, "invalid token %d", token))
649 		return NULL;
650 
651 	func = rtas_token_to_function_untrusted(token);
652 	if (func)
653 		return func;
654 	/*
655 	 * Fall back to linear scan in case the reverse mapping hasn't
656 	 * been initialized yet.
657 	 */
658 	if (xa_empty(&rtas_token_to_function_xarray)) {
659 		for_each_rtas_function(func) {
660 			if (func->token == token)
661 				return func;
662 		}
663 	}
664 
665 	WARN_ONCE(true, "unexpected failed lookup for token %d", token);
666 	return NULL;
667 }
668 
669 /* This is here deliberately so it's only used in this file */
670 void enter_rtas(unsigned long);
671 
672 static void __do_enter_rtas(struct rtas_args *args)
673 {
674 	enter_rtas(__pa(args));
675 	srr_regs_clobbered(); /* rtas uses SRRs, invalidate */
676 }
677 
678 static void __do_enter_rtas_trace(struct rtas_args *args)
679 {
680 	const struct rtas_function *func = rtas_token_to_function(be32_to_cpu(args->token));
681 
682 	/*
683 	 * If there is a per-function lock, it must be held by the
684 	 * caller.
685 	 */
686 	if (func->lock)
687 		lockdep_assert_held(func->lock);
688 
689 	if (args == &rtas_args)
690 		lockdep_assert_held(&rtas_lock);
691 
692 	trace_rtas_input(args, func->name);
693 	trace_rtas_ll_entry(args);
694 
695 	__do_enter_rtas(args);
696 
697 	trace_rtas_ll_exit(args);
698 	trace_rtas_output(args, func->name);
699 }
700 
701 static void do_enter_rtas(struct rtas_args *args)
702 {
703 	const unsigned long msr = mfmsr();
704 	/*
705 	 * Situations where we want to skip any active tracepoints for
706 	 * safety reasons:
707 	 *
708 	 * 1. The last code executed on an offline CPU as it stops,
709 	 *    i.e. we're about to call stop-self. The tracepoints'
710 	 *    function name lookup uses xarray, which uses RCU, which
711 	 *    isn't valid to call on an offline CPU.  Any events
712 	 *    emitted on an offline CPU will be discarded anyway.
713 	 *
714 	 * 2. In real mode, as when invoking ibm,nmi-interlock from
715 	 *    the pseries MCE handler. We cannot count on trace
716 	 *    buffers or the entries in rtas_token_to_function_xarray
717 	 *    to be contained in the RMO.
718 	 */
719 	const unsigned long mask = MSR_IR | MSR_DR;
720 	const bool can_trace = likely(cpu_online(raw_smp_processor_id()) &&
721 				      (msr & mask) == mask);
722 	/*
723 	 * Make sure MSR[RI] is currently enabled as it will be forced later
724 	 * in enter_rtas.
725 	 */
726 	BUG_ON(!(msr & MSR_RI));
727 
728 	BUG_ON(!irqs_disabled());
729 
730 	hard_irq_disable(); /* Ensure MSR[EE] is disabled on PPC64 */
731 
732 	if (can_trace)
733 		__do_enter_rtas_trace(args);
734 	else
735 		__do_enter_rtas(args);
736 }
737 
738 struct rtas_t rtas;
739 
740 DEFINE_SPINLOCK(rtas_data_buf_lock);
741 EXPORT_SYMBOL_GPL(rtas_data_buf_lock);
742 
743 char rtas_data_buf[RTAS_DATA_BUF_SIZE] __aligned(SZ_4K);
744 EXPORT_SYMBOL_GPL(rtas_data_buf);
745 
746 unsigned long rtas_rmo_buf;
747 
748 /*
749  * If non-NULL, this gets called when the kernel terminates.
750  * This is done like this so rtas_flash can be a module.
751  */
752 void (*rtas_flash_term_hook)(int);
753 EXPORT_SYMBOL_GPL(rtas_flash_term_hook);
754 
755 /*
756  * call_rtas_display_status and call_rtas_display_status_delay
757  * are designed only for very early low-level debugging, which
758  * is why the token is hard-coded to 10.
759  */
760 static void call_rtas_display_status(unsigned char c)
761 {
762 	unsigned long flags;
763 
764 	if (!rtas.base)
765 		return;
766 
767 	raw_spin_lock_irqsave(&rtas_lock, flags);
768 	rtas_call_unlocked(&rtas_args, 10, 1, 1, NULL, c);
769 	raw_spin_unlock_irqrestore(&rtas_lock, flags);
770 }
771 
772 static void call_rtas_display_status_delay(char c)
773 {
774 	static int pending_newline = 0;  /* did last write end with unprinted newline? */
775 	static int width = 16;
776 
777 	if (c == '\n') {
778 		while (width-- > 0)
779 			call_rtas_display_status(' ');
780 		width = 16;
781 		mdelay(500);
782 		pending_newline = 1;
783 	} else {
784 		if (pending_newline) {
785 			call_rtas_display_status('\r');
786 			call_rtas_display_status('\n');
787 		}
788 		pending_newline = 0;
789 		if (width--) {
790 			call_rtas_display_status(c);
791 			udelay(10000);
792 		}
793 	}
794 }
795 
796 void __init udbg_init_rtas_panel(void)
797 {
798 	udbg_putc = call_rtas_display_status_delay;
799 }
800 
801 #ifdef CONFIG_UDBG_RTAS_CONSOLE
802 
803 /* If you think you're dying before early_init_dt_scan_rtas() does its
804  * work, you can hard code the token values for your firmware here and
805  * hardcode rtas.base/entry etc.
806  */
807 static unsigned int rtas_putchar_token = RTAS_UNKNOWN_SERVICE;
808 static unsigned int rtas_getchar_token = RTAS_UNKNOWN_SERVICE;
809 
810 static void udbg_rtascon_putc(char c)
811 {
812 	int tries;
813 
814 	if (!rtas.base)
815 		return;
816 
817 	/* Add CRs before LFs */
818 	if (c == '\n')
819 		udbg_rtascon_putc('\r');
820 
821 	/* if there is more than one character to be displayed, wait a bit */
822 	for (tries = 0; tries < 16; tries++) {
823 		if (rtas_call(rtas_putchar_token, 1, 1, NULL, c) == 0)
824 			break;
825 		udelay(1000);
826 	}
827 }
828 
829 static int udbg_rtascon_getc_poll(void)
830 {
831 	int c;
832 
833 	if (!rtas.base)
834 		return -1;
835 
836 	if (rtas_call(rtas_getchar_token, 0, 2, &c))
837 		return -1;
838 
839 	return c;
840 }
841 
842 static int udbg_rtascon_getc(void)
843 {
844 	int c;
845 
846 	while ((c = udbg_rtascon_getc_poll()) == -1)
847 		;
848 
849 	return c;
850 }
851 
852 
853 void __init udbg_init_rtas_console(void)
854 {
855 	udbg_putc = udbg_rtascon_putc;
856 	udbg_getc = udbg_rtascon_getc;
857 	udbg_getc_poll = udbg_rtascon_getc_poll;
858 }
859 #endif /* CONFIG_UDBG_RTAS_CONSOLE */
860 
861 void rtas_progress(char *s, unsigned short hex)
862 {
863 	struct device_node *root;
864 	int width;
865 	const __be32 *p;
866 	char *os;
867 	static int display_character, set_indicator;
868 	static int display_width, display_lines, form_feed;
869 	static const int *row_width;
870 	static DEFINE_SPINLOCK(progress_lock);
871 	static int current_line;
872 	static int pending_newline = 0;  /* did last write end with unprinted newline? */
873 
874 	if (!rtas.base)
875 		return;
876 
877 	if (display_width == 0) {
878 		display_width = 0x10;
879 		if ((root = of_find_node_by_path("/rtas"))) {
880 			if ((p = of_get_property(root,
881 					"ibm,display-line-length", NULL)))
882 				display_width = be32_to_cpu(*p);
883 			if ((p = of_get_property(root,
884 					"ibm,form-feed", NULL)))
885 				form_feed = be32_to_cpu(*p);
886 			if ((p = of_get_property(root,
887 					"ibm,display-number-of-lines", NULL)))
888 				display_lines = be32_to_cpu(*p);
889 			row_width = of_get_property(root,
890 					"ibm,display-truncation-length", NULL);
891 			of_node_put(root);
892 		}
893 		display_character = rtas_function_token(RTAS_FN_DISPLAY_CHARACTER);
894 		set_indicator = rtas_function_token(RTAS_FN_SET_INDICATOR);
895 	}
896 
897 	if (display_character == RTAS_UNKNOWN_SERVICE) {
898 		/* use hex display if available */
899 		if (set_indicator != RTAS_UNKNOWN_SERVICE)
900 			rtas_call(set_indicator, 3, 1, NULL, 6, 0, hex);
901 		return;
902 	}
903 
904 	spin_lock(&progress_lock);
905 
906 	/*
907 	 * Last write ended with newline, but we didn't print it since
908 	 * it would just clear the bottom line of output. Print it now
909 	 * instead.
910 	 *
911 	 * If no newline is pending and form feed is supported, clear the
912 	 * display with a form feed; otherwise, print a CR to start output
913 	 * at the beginning of the line.
914 	 */
915 	if (pending_newline) {
916 		rtas_call(display_character, 1, 1, NULL, '\r');
917 		rtas_call(display_character, 1, 1, NULL, '\n');
918 		pending_newline = 0;
919 	} else {
920 		current_line = 0;
921 		if (form_feed)
922 			rtas_call(display_character, 1, 1, NULL,
923 				  (char)form_feed);
924 		else
925 			rtas_call(display_character, 1, 1, NULL, '\r');
926 	}
927 
928 	if (row_width)
929 		width = row_width[current_line];
930 	else
931 		width = display_width;
932 	os = s;
933 	while (*os) {
934 		if (*os == '\n' || *os == '\r') {
935 			/* If newline is the last character, save it
936 			 * until next call to avoid bumping up the
937 			 * display output.
938 			 */
939 			if (*os == '\n' && !os[1]) {
940 				pending_newline = 1;
941 				current_line++;
942 				if (current_line > display_lines-1)
943 					current_line = display_lines-1;
944 				spin_unlock(&progress_lock);
945 				return;
946 			}
947 
948 			/* RTAS wants CR-LF, not just LF */
949 
950 			if (*os == '\n') {
951 				rtas_call(display_character, 1, 1, NULL, '\r');
952 				rtas_call(display_character, 1, 1, NULL, '\n');
953 			} else {
954 				/* CR might be used to re-draw a line, so we'll
955 				 * leave it alone and not add LF.
956 				 */
957 				rtas_call(display_character, 1, 1, NULL, *os);
958 			}
959 
960 			if (row_width)
961 				width = row_width[current_line];
962 			else
963 				width = display_width;
964 		} else {
965 			width--;
966 			rtas_call(display_character, 1, 1, NULL, *os);
967 		}
968 
969 		os++;
970 
971 		/* if we overwrite the screen length */
972 		if (width <= 0)
973 			while ((*os != 0) && (*os != '\n') && (*os != '\r'))
974 				os++;
975 	}
976 
977 	spin_unlock(&progress_lock);
978 }
979 EXPORT_SYMBOL_GPL(rtas_progress);		/* needed by rtas_flash module */
980 
981 int rtas_token(const char *service)
982 {
983 	const struct rtas_function *func;
984 	const __be32 *tokp;
985 
986 	if (rtas.dev == NULL)
987 		return RTAS_UNKNOWN_SERVICE;
988 
989 	func = rtas_name_to_function(service);
990 	if (func)
991 		return func->token;
992 	/*
993 	 * The caller is looking up a name that is not known to be an
994 	 * RTAS function. Either it's a function that needs to be
995 	 * added to the table, or they're misusing rtas_token() to
996 	 * access non-function properties of the /rtas node. Warn and
997 	 * fall back to the legacy behavior.
998 	 */
999 	WARN_ONCE(1, "unknown function `%s`, should it be added to rtas_function_table?\n",
1000 		  service);
1001 
1002 	tokp = of_get_property(rtas.dev, service, NULL);
1003 	return tokp ? be32_to_cpu(*tokp) : RTAS_UNKNOWN_SERVICE;
1004 }
1005 EXPORT_SYMBOL_GPL(rtas_token);
1006 
1007 #ifdef CONFIG_RTAS_ERROR_LOGGING
1008 
1009 static u32 rtas_error_log_max __ro_after_init = RTAS_ERROR_LOG_MAX;
1010 
1011 /*
1012  * Return the firmware-specified size of the error log buffer
1013  *  for all rtas calls that require an error buffer argument.
1014  *  This includes 'check-exception' and 'rtas-last-error'.
1015  */
1016 int rtas_get_error_log_max(void)
1017 {
1018 	return rtas_error_log_max;
1019 }
1020 
1021 static void __init init_error_log_max(void)
1022 {
1023 	static const char propname[] __initconst = "rtas-error-log-max";
1024 	u32 max;
1025 
1026 	if (of_property_read_u32(rtas.dev, propname, &max)) {
1027 		pr_warn("%s not found, using default of %u\n",
1028 			propname, RTAS_ERROR_LOG_MAX);
1029 		max = RTAS_ERROR_LOG_MAX;
1030 	}
1031 
1032 	if (max > RTAS_ERROR_LOG_MAX) {
1033 		pr_warn("%s = %u, clamping max error log size to %u\n",
1034 			propname, max, RTAS_ERROR_LOG_MAX);
1035 		max = RTAS_ERROR_LOG_MAX;
1036 	}
1037 
1038 	rtas_error_log_max = max;
1039 }
1040 
1041 
1042 static char rtas_err_buf[RTAS_ERROR_LOG_MAX];
1043 
1044 /** Return a copy of the detailed error text associated with the
1045  *  most recent failed call to rtas.  Because the error text
1046  *  might go stale if there are any other intervening rtas calls,
1047  *  this routine must be called atomically with whatever produced
1048  *  the error (i.e. with rtas_lock still held from the previous call).
1049  */
1050 static char *__fetch_rtas_last_error(char *altbuf)
1051 {
1052 	const s32 token = rtas_function_token(RTAS_FN_RTAS_LAST_ERROR);
1053 	struct rtas_args err_args, save_args;
1054 	u32 bufsz;
1055 	char *buf = NULL;
1056 
1057 	lockdep_assert_held(&rtas_lock);
1058 
1059 	if (token == -1)
1060 		return NULL;
1061 
1062 	bufsz = rtas_get_error_log_max();
1063 
1064 	err_args.token = cpu_to_be32(token);
1065 	err_args.nargs = cpu_to_be32(2);
1066 	err_args.nret = cpu_to_be32(1);
1067 	err_args.args[0] = cpu_to_be32(__pa(rtas_err_buf));
1068 	err_args.args[1] = cpu_to_be32(bufsz);
1069 	err_args.args[2] = 0;
1070 
1071 	save_args = rtas_args;
1072 	rtas_args = err_args;
1073 
1074 	do_enter_rtas(&rtas_args);
1075 
1076 	err_args = rtas_args;
1077 	rtas_args = save_args;
1078 
1079 	/* Log the error in the unlikely case that there was one. */
1080 	if (unlikely(err_args.args[2] == 0)) {
1081 		if (altbuf) {
1082 			buf = altbuf;
1083 		} else {
1084 			buf = rtas_err_buf;
1085 			if (slab_is_available())
1086 				buf = kmalloc(RTAS_ERROR_LOG_MAX, GFP_ATOMIC);
1087 		}
1088 		if (buf)
1089 			memmove(buf, rtas_err_buf, RTAS_ERROR_LOG_MAX);
1090 	}
1091 
1092 	return buf;
1093 }
1094 
1095 #define get_errorlog_buffer()	kmalloc(RTAS_ERROR_LOG_MAX, GFP_KERNEL)
1096 
1097 #else /* CONFIG_RTAS_ERROR_LOGGING */
1098 #define __fetch_rtas_last_error(x)	NULL
1099 #define get_errorlog_buffer()		NULL
1100 static void __init init_error_log_max(void) {}
1101 #endif
1102 
1103 
1104 static void
1105 va_rtas_call_unlocked(struct rtas_args *args, int token, int nargs, int nret,
1106 		      va_list list)
1107 {
1108 	int i;
1109 
1110 	args->token = cpu_to_be32(token);
1111 	args->nargs = cpu_to_be32(nargs);
1112 	args->nret  = cpu_to_be32(nret);
1113 	args->rets  = &(args->args[nargs]);
1114 
1115 	for (i = 0; i < nargs; ++i)
1116 		args->args[i] = cpu_to_be32(va_arg(list, __u32));
1117 
1118 	for (i = 0; i < nret; ++i)
1119 		args->rets[i] = 0;
1120 
1121 	do_enter_rtas(args);
1122 }
1123 
1124 /**
1125  * rtas_call_unlocked() - Invoke an RTAS firmware function without synchronization.
1126  * @args: RTAS parameter block to be used for the call, must obey RTAS addressing
1127  *        constraints.
1128  * @token: Identifies the function being invoked.
1129  * @nargs: Number of input parameters. Does not include token.
1130  * @nret: Number of output parameters, including the call status.
1131  * @....: List of @nargs input parameters.
1132  *
1133  * Invokes the RTAS function indicated by @token, which the caller
1134  * should obtain via rtas_function_token().
1135  *
1136  * This function is similar to rtas_call(), but must be used with a
1137  * limited set of RTAS calls specifically exempted from the general
1138  * requirement that only one RTAS call may be in progress at any
1139  * time. Examples include stop-self and ibm,nmi-interlock.
1140  */
1141 void rtas_call_unlocked(struct rtas_args *args, int token, int nargs, int nret, ...)
1142 {
1143 	va_list list;
1144 
1145 	va_start(list, nret);
1146 	va_rtas_call_unlocked(args, token, nargs, nret, list);
1147 	va_end(list);
1148 }
1149 
1150 static bool token_is_restricted_errinjct(s32 token)
1151 {
1152 	return token == rtas_function_token(RTAS_FN_IBM_OPEN_ERRINJCT) ||
1153 	       token == rtas_function_token(RTAS_FN_IBM_ERRINJCT);
1154 }
1155 
1156 /**
1157  * rtas_call() - Invoke an RTAS firmware function.
1158  * @token: Identifies the function being invoked.
1159  * @nargs: Number of input parameters. Does not include token.
1160  * @nret: Number of output parameters, including the call status.
1161  * @outputs: Array of @nret output words.
1162  * @....: List of @nargs input parameters.
1163  *
1164  * Invokes the RTAS function indicated by @token, which the caller
1165  * should obtain via rtas_function_token().
1166  *
1167  * The @nargs and @nret arguments must match the number of input and
1168  * output parameters specified for the RTAS function.
1169  *
1170  * rtas_call() returns RTAS status codes, not conventional Linux errno
1171  * values. Callers must translate any failure to an appropriate errno
1172  * in syscall context. Most callers of RTAS functions that can return
1173  * -2 or 990x should use rtas_busy_delay() to correctly handle those
1174  * statuses before calling again.
1175  *
1176  * The return value descriptions are adapted from 7.2.8 [RTAS] Return
1177  * Codes of the PAPR and CHRP specifications.
1178  *
1179  * Context: Process context preferably, interrupt context if
1180  *          necessary.  Acquires an internal spinlock and may perform
1181  *          GFP_ATOMIC slab allocation in error path. Unsafe for NMI
1182  *          context.
1183  * Return:
1184  * *                          0 - RTAS function call succeeded.
1185  * *                         -1 - RTAS function encountered a hardware or
1186  *                                platform error, or the token is invalid,
1187  *                                or the function is restricted by kernel policy.
1188  * *                         -2 - Specs say "A necessary hardware device was busy,
1189  *                                and the requested function could not be
1190  *                                performed. The operation should be retried at
1191  *                                a later time." This is misleading, at least with
1192  *                                respect to current RTAS implementations. What it
1193  *                                usually means in practice is that the function
1194  *                                could not be completed while meeting RTAS's
1195  *                                deadline for returning control to the OS (250us
1196  *                                for PAPR/PowerVM, typically), but the call may be
1197  *                                immediately reattempted to resume work on it.
1198  * *                         -3 - Parameter error.
1199  * *                         -7 - Unexpected state change.
1200  * *                9000...9899 - Vendor-specific success codes.
1201  * *                9900...9905 - Advisory extended delay. Caller should try
1202  *                                again after ~10^x ms has elapsed, where x is
1203  *                                the last digit of the status [0-5]. Again going
1204  *                                beyond the PAPR text, 990x on PowerVM indicates
1205  *                                contention for RTAS-internal resources. Other
1206  *                                RTAS call sequences in progress should be
1207  *                                allowed to complete before reattempting the
1208  *                                call.
1209  * *                      -9000 - Multi-level isolation error.
1210  * *              -9999...-9004 - Vendor-specific error codes.
1211  * * Additional negative values - Function-specific error.
1212  * * Additional positive values - Function-specific success.
1213  */
1214 int rtas_call(int token, int nargs, int nret, int *outputs, ...)
1215 {
1216 	struct pin_cookie cookie;
1217 	va_list list;
1218 	int i;
1219 	unsigned long flags;
1220 	struct rtas_args *args;
1221 	char *buff_copy = NULL;
1222 	int ret;
1223 
1224 	if (!rtas.entry || token == RTAS_UNKNOWN_SERVICE)
1225 		return -1;
1226 
1227 	if (token_is_restricted_errinjct(token)) {
1228 		/*
1229 		 * It would be nicer to not discard the error value
1230 		 * from security_locked_down(), but callers expect an
1231 		 * RTAS status, not an errno.
1232 		 */
1233 		if (security_locked_down(LOCKDOWN_RTAS_ERROR_INJECTION))
1234 			return -1;
1235 	}
1236 
1237 	if ((mfmsr() & (MSR_IR|MSR_DR)) != (MSR_IR|MSR_DR)) {
1238 		WARN_ON_ONCE(1);
1239 		return -1;
1240 	}
1241 
1242 	raw_spin_lock_irqsave(&rtas_lock, flags);
1243 	cookie = lockdep_pin_lock(&rtas_lock);
1244 
1245 	/* We use the global rtas args buffer */
1246 	args = &rtas_args;
1247 
1248 	va_start(list, outputs);
1249 	va_rtas_call_unlocked(args, token, nargs, nret, list);
1250 	va_end(list);
1251 
1252 	/* A -1 return code indicates that the last command couldn't
1253 	   be completed due to a hardware error. */
1254 	if (be32_to_cpu(args->rets[0]) == -1)
1255 		buff_copy = __fetch_rtas_last_error(NULL);
1256 
1257 	if (nret > 1 && outputs != NULL)
1258 		for (i = 0; i < nret-1; ++i)
1259 			outputs[i] = be32_to_cpu(args->rets[i + 1]);
1260 	ret = (nret > 0) ? be32_to_cpu(args->rets[0]) : 0;
1261 
1262 	lockdep_unpin_lock(&rtas_lock, cookie);
1263 	raw_spin_unlock_irqrestore(&rtas_lock, flags);
1264 
1265 	if (buff_copy) {
1266 		log_error(buff_copy, ERR_TYPE_RTAS_LOG, 0);
1267 		if (slab_is_available())
1268 			kfree(buff_copy);
1269 	}
1270 	return ret;
1271 }
1272 EXPORT_SYMBOL_GPL(rtas_call);
1273 
1274 /**
1275  * rtas_busy_delay_time() - From an RTAS status value, calculate the
1276  *                          suggested delay time in milliseconds.
1277  *
1278  * @status: a value returned from rtas_call() or similar APIs which return
1279  *          the status of a RTAS function call.
1280  *
1281  * Context: Any context.
1282  *
1283  * Return:
1284  * * 100000 - If @status is 9905.
1285  * * 10000  - If @status is 9904.
1286  * * 1000   - If @status is 9903.
1287  * * 100    - If @status is 9902.
1288  * * 10     - If @status is 9901.
1289  * * 1      - If @status is either 9900 or -2. This is "wrong" for -2, but
1290  *            some callers depend on this behavior, and the worst outcome
1291  *            is that they will delay for longer than necessary.
1292  * * 0      - If @status is not a busy or extended delay value.
1293  */
1294 unsigned int rtas_busy_delay_time(int status)
1295 {
1296 	int order;
1297 	unsigned int ms = 0;
1298 
1299 	if (status == RTAS_BUSY) {
1300 		ms = 1;
1301 	} else if (status >= RTAS_EXTENDED_DELAY_MIN &&
1302 		   status <= RTAS_EXTENDED_DELAY_MAX) {
1303 		order = status - RTAS_EXTENDED_DELAY_MIN;
1304 		for (ms = 1; order > 0; order--)
1305 			ms *= 10;
1306 	}
1307 
1308 	return ms;
1309 }
1310 
1311 /*
1312  * Early boot fallback for rtas_busy_delay().
1313  */
1314 static bool __init rtas_busy_delay_early(int status)
1315 {
1316 	static size_t successive_ext_delays __initdata;
1317 	bool retry;
1318 
1319 	switch (status) {
1320 	case RTAS_EXTENDED_DELAY_MIN...RTAS_EXTENDED_DELAY_MAX:
1321 		/*
1322 		 * In the unlikely case that we receive an extended
1323 		 * delay status in early boot, the OS is probably not
1324 		 * the cause, and there's nothing we can do to clear
1325 		 * the condition. Best we can do is delay for a bit
1326 		 * and hope it's transient. Lie to the caller if it
1327 		 * seems like we're stuck in a retry loop.
1328 		 */
1329 		mdelay(1);
1330 		retry = true;
1331 		successive_ext_delays += 1;
1332 		if (successive_ext_delays > 1000) {
1333 			pr_err("too many extended delays, giving up\n");
1334 			dump_stack();
1335 			retry = false;
1336 			successive_ext_delays = 0;
1337 		}
1338 		break;
1339 	case RTAS_BUSY:
1340 		retry = true;
1341 		successive_ext_delays = 0;
1342 		break;
1343 	default:
1344 		retry = false;
1345 		successive_ext_delays = 0;
1346 		break;
1347 	}
1348 
1349 	return retry;
1350 }
1351 
1352 /**
1353  * rtas_busy_delay() - helper for RTAS busy and extended delay statuses
1354  *
1355  * @status: a value returned from rtas_call() or similar APIs which return
1356  *          the status of a RTAS function call.
1357  *
1358  * Context: Process context. May sleep or schedule.
1359  *
1360  * Return:
1361  * * true  - @status is RTAS_BUSY or an extended delay hint. The
1362  *           caller may assume that the CPU has been yielded if necessary,
1363  *           and that an appropriate delay for @status has elapsed.
1364  *           Generally the caller should reattempt the RTAS call which
1365  *           yielded @status.
1366  *
1367  * * false - @status is not @RTAS_BUSY nor an extended delay hint. The
1368  *           caller is responsible for handling @status.
1369  */
1370 bool __ref rtas_busy_delay(int status)
1371 {
1372 	unsigned int ms;
1373 	bool ret;
1374 
1375 	/*
1376 	 * Can't do timed sleeps before timekeeping is up.
1377 	 */
1378 	if (system_state < SYSTEM_SCHEDULING)
1379 		return rtas_busy_delay_early(status);
1380 
1381 	switch (status) {
1382 	case RTAS_EXTENDED_DELAY_MIN...RTAS_EXTENDED_DELAY_MAX:
1383 		ret = true;
1384 		ms = rtas_busy_delay_time(status);
1385 		/*
1386 		 * The extended delay hint can be as high as 100 seconds.
1387 		 * Surely any function returning such a status is either
1388 		 * buggy or isn't going to be significantly slowed by us
1389 		 * polling at 1HZ. Clamp the sleep time to one second.
1390 		 */
1391 		ms = clamp(ms, 1U, 1000U);
1392 		/*
1393 		 * The delay hint is an order-of-magnitude suggestion, not a
1394 		 * minimum. It is fine, possibly even advantageous, for us to
1395 		 * pause for less time than hinted. To make sure pause time will
1396 		 * not be way longer than requested independent of HZ
1397 		 * configuration, use fsleep(). See fsleep() for details of
1398 		 * used sleeping functions.
1399 		 */
1400 		fsleep(ms * 1000);
1401 		break;
1402 	case RTAS_BUSY:
1403 		ret = true;
1404 		/*
1405 		 * We should call again immediately if there's no other
1406 		 * work to do.
1407 		 */
1408 		cond_resched();
1409 		break;
1410 	default:
1411 		ret = false;
1412 		/*
1413 		 * Not a busy or extended delay status; the caller should
1414 		 * handle @status itself. Ensure we warn on misuses in
1415 		 * atomic context regardless.
1416 		 */
1417 		might_sleep();
1418 		break;
1419 	}
1420 
1421 	return ret;
1422 }
1423 EXPORT_SYMBOL_GPL(rtas_busy_delay);
1424 
1425 int rtas_error_rc(int rtas_rc)
1426 {
1427 	int rc;
1428 
1429 	switch (rtas_rc) {
1430 	case RTAS_HARDWARE_ERROR:	/* Hardware Error */
1431 		rc = -EIO;
1432 		break;
1433 	case RTAS_INVALID_PARAMETER:	/* Bad indicator/domain/etc */
1434 		rc = -EINVAL;
1435 		break;
1436 	case -9000:			/* Isolation error */
1437 		rc = -EFAULT;
1438 		break;
1439 	case -9001:			/* Outstanding TCE/PTE */
1440 		rc = -EEXIST;
1441 		break;
1442 	case -9002:			/* No usable slot */
1443 		rc = -ENODEV;
1444 		break;
1445 	default:
1446 		pr_err("%s: unexpected error %d\n", __func__, rtas_rc);
1447 		rc = -ERANGE;
1448 		break;
1449 	}
1450 	return rc;
1451 }
1452 EXPORT_SYMBOL_GPL(rtas_error_rc);
1453 
1454 int rtas_get_power_level(int powerdomain, int *level)
1455 {
1456 	int token = rtas_function_token(RTAS_FN_GET_POWER_LEVEL);
1457 	int rc;
1458 
1459 	if (token == RTAS_UNKNOWN_SERVICE)
1460 		return -ENOENT;
1461 
1462 	while ((rc = rtas_call(token, 1, 2, level, powerdomain)) == RTAS_BUSY)
1463 		udelay(1);
1464 
1465 	if (rc < 0)
1466 		return rtas_error_rc(rc);
1467 	return rc;
1468 }
1469 EXPORT_SYMBOL_GPL(rtas_get_power_level);
1470 
1471 int rtas_set_power_level(int powerdomain, int level, int *setlevel)
1472 {
1473 	int token = rtas_function_token(RTAS_FN_SET_POWER_LEVEL);
1474 	int rc;
1475 
1476 	if (token == RTAS_UNKNOWN_SERVICE)
1477 		return -ENOENT;
1478 
1479 	do {
1480 		rc = rtas_call(token, 2, 2, setlevel, powerdomain, level);
1481 	} while (rtas_busy_delay(rc));
1482 
1483 	if (rc < 0)
1484 		return rtas_error_rc(rc);
1485 	return rc;
1486 }
1487 EXPORT_SYMBOL_GPL(rtas_set_power_level);
1488 
1489 int rtas_get_sensor(int sensor, int index, int *state)
1490 {
1491 	int token = rtas_function_token(RTAS_FN_GET_SENSOR_STATE);
1492 	int rc;
1493 
1494 	if (token == RTAS_UNKNOWN_SERVICE)
1495 		return -ENOENT;
1496 
1497 	do {
1498 		rc = rtas_call(token, 2, 2, state, sensor, index);
1499 	} while (rtas_busy_delay(rc));
1500 
1501 	if (rc < 0)
1502 		return rtas_error_rc(rc);
1503 	return rc;
1504 }
1505 EXPORT_SYMBOL_GPL(rtas_get_sensor);
1506 
1507 int rtas_get_sensor_fast(int sensor, int index, int *state)
1508 {
1509 	int token = rtas_function_token(RTAS_FN_GET_SENSOR_STATE);
1510 	int rc;
1511 
1512 	if (token == RTAS_UNKNOWN_SERVICE)
1513 		return -ENOENT;
1514 
1515 	rc = rtas_call(token, 2, 2, state, sensor, index);
1516 	WARN_ON(rc == RTAS_BUSY || (rc >= RTAS_EXTENDED_DELAY_MIN &&
1517 				    rc <= RTAS_EXTENDED_DELAY_MAX));
1518 
1519 	if (rc < 0)
1520 		return rtas_error_rc(rc);
1521 	return rc;
1522 }
1523 
1524 bool rtas_indicator_present(int token, int *maxindex)
1525 {
1526 	int proplen, count, i;
1527 	const struct indicator_elem {
1528 		__be32 token;
1529 		__be32 maxindex;
1530 	} *indicators;
1531 
1532 	indicators = of_get_property(rtas.dev, "rtas-indicators", &proplen);
1533 	if (!indicators)
1534 		return false;
1535 
1536 	count = proplen / sizeof(struct indicator_elem);
1537 
1538 	for (i = 0; i < count; i++) {
1539 		if (__be32_to_cpu(indicators[i].token) != token)
1540 			continue;
1541 		if (maxindex)
1542 			*maxindex = __be32_to_cpu(indicators[i].maxindex);
1543 		return true;
1544 	}
1545 
1546 	return false;
1547 }
1548 
1549 int rtas_set_indicator(int indicator, int index, int new_value)
1550 {
1551 	int token = rtas_function_token(RTAS_FN_SET_INDICATOR);
1552 	int rc;
1553 
1554 	if (token == RTAS_UNKNOWN_SERVICE)
1555 		return -ENOENT;
1556 
1557 	do {
1558 		rc = rtas_call(token, 3, 1, NULL, indicator, index, new_value);
1559 	} while (rtas_busy_delay(rc));
1560 
1561 	if (rc < 0)
1562 		return rtas_error_rc(rc);
1563 	return rc;
1564 }
1565 EXPORT_SYMBOL_GPL(rtas_set_indicator);
1566 
1567 /*
1568  * Ignoring RTAS extended delay
1569  */
1570 int rtas_set_indicator_fast(int indicator, int index, int new_value)
1571 {
1572 	int token = rtas_function_token(RTAS_FN_SET_INDICATOR);
1573 	int rc;
1574 
1575 	if (token == RTAS_UNKNOWN_SERVICE)
1576 		return -ENOENT;
1577 
1578 	rc = rtas_call(token, 3, 1, NULL, indicator, index, new_value);
1579 
1580 	WARN_ON(rc == RTAS_BUSY || (rc >= RTAS_EXTENDED_DELAY_MIN &&
1581 				    rc <= RTAS_EXTENDED_DELAY_MAX));
1582 
1583 	if (rc < 0)
1584 		return rtas_error_rc(rc);
1585 
1586 	return rc;
1587 }
1588 
1589 /**
1590  * rtas_ibm_suspend_me() - Call ibm,suspend-me to suspend the LPAR.
1591  *
1592  * @fw_status: RTAS call status will be placed here if not NULL.
1593  *
1594  * rtas_ibm_suspend_me() should be called only on a CPU which has
1595  * received H_CONTINUE from the H_JOIN hcall. All other active CPUs
1596  * should be waiting to return from H_JOIN.
1597  *
1598  * rtas_ibm_suspend_me() may suspend execution of the OS
1599  * indefinitely. Callers should take appropriate measures upon return, such as
1600  * resetting watchdog facilities.
1601  *
1602  * Callers may choose to retry this call if @fw_status is
1603  * %RTAS_THREADS_ACTIVE.
1604  *
1605  * Return:
1606  * 0          - The partition has resumed from suspend, possibly after
1607  *              migration to a different host.
1608  * -ECANCELED - The operation was aborted.
1609  * -EAGAIN    - There were other CPUs not in H_JOIN at the time of the call.
1610  * -EBUSY     - Some other condition prevented the suspend from succeeding.
1611  * -EIO       - Hardware/platform error.
1612  */
1613 int rtas_ibm_suspend_me(int *fw_status)
1614 {
1615 	int token = rtas_function_token(RTAS_FN_IBM_SUSPEND_ME);
1616 	int fwrc;
1617 	int ret;
1618 
1619 	fwrc = rtas_call(token, 0, 1, NULL);
1620 
1621 	switch (fwrc) {
1622 	case 0:
1623 		ret = 0;
1624 		break;
1625 	case RTAS_SUSPEND_ABORTED:
1626 		ret = -ECANCELED;
1627 		break;
1628 	case RTAS_THREADS_ACTIVE:
1629 		ret = -EAGAIN;
1630 		break;
1631 	case RTAS_NOT_SUSPENDABLE:
1632 	case RTAS_OUTSTANDING_COPROC:
1633 		ret = -EBUSY;
1634 		break;
1635 	case -1:
1636 	default:
1637 		ret = -EIO;
1638 		break;
1639 	}
1640 
1641 	if (fw_status)
1642 		*fw_status = fwrc;
1643 
1644 	return ret;
1645 }
1646 
1647 void __noreturn rtas_restart(char *cmd)
1648 {
1649 	if (rtas_flash_term_hook)
1650 		rtas_flash_term_hook(SYS_RESTART);
1651 	pr_emerg("system-reboot returned %d\n",
1652 		 rtas_call(rtas_function_token(RTAS_FN_SYSTEM_REBOOT), 0, 1, NULL));
1653 	for (;;);
1654 }
1655 
1656 void rtas_power_off(void)
1657 {
1658 	if (rtas_flash_term_hook)
1659 		rtas_flash_term_hook(SYS_POWER_OFF);
1660 	/* allow power on only with power button press */
1661 	pr_emerg("power-off returned %d\n",
1662 		 rtas_call(rtas_function_token(RTAS_FN_POWER_OFF), 2, 1, NULL, -1, -1));
1663 	for (;;);
1664 }
1665 
1666 void __noreturn rtas_halt(void)
1667 {
1668 	if (rtas_flash_term_hook)
1669 		rtas_flash_term_hook(SYS_HALT);
1670 	/* allow power on only with power button press */
1671 	pr_emerg("power-off returned %d\n",
1672 		 rtas_call(rtas_function_token(RTAS_FN_POWER_OFF), 2, 1, NULL, -1, -1));
1673 	for (;;);
1674 }
1675 
1676 /* Must be in the RMO region, so we place it here */
1677 static char rtas_os_term_buf[2048];
1678 static bool ibm_extended_os_term;
1679 
1680 void rtas_os_term(char *str)
1681 {
1682 	s32 token = rtas_function_token(RTAS_FN_IBM_OS_TERM);
1683 	static struct rtas_args args;
1684 	int status;
1685 
1686 	/*
1687 	 * Firmware with the ibm,extended-os-term property is guaranteed
1688 	 * to always return from an ibm,os-term call. Earlier versions without
1689 	 * this property may terminate the partition which we want to avoid
1690 	 * since it interferes with panic_timeout.
1691 	 */
1692 
1693 	if (token == RTAS_UNKNOWN_SERVICE || !ibm_extended_os_term)
1694 		return;
1695 
1696 	snprintf(rtas_os_term_buf, 2048, "OS panic: %s", str);
1697 
1698 	/*
1699 	 * Keep calling as long as RTAS returns a "try again" status,
1700 	 * but don't use rtas_busy_delay(), which potentially
1701 	 * schedules.
1702 	 */
1703 	do {
1704 		rtas_call_unlocked(&args, token, 1, 1, NULL, __pa(rtas_os_term_buf));
1705 		status = be32_to_cpu(args.rets[0]);
1706 	} while (rtas_busy_delay_time(status));
1707 
1708 	if (status != 0)
1709 		pr_emerg("ibm,os-term call failed %d\n", status);
1710 }
1711 
1712 /**
1713  * rtas_activate_firmware() - Activate a new version of firmware.
1714  *
1715  * Context: This function may sleep.
1716  *
1717  * Activate a new version of partition firmware. The OS must call this
1718  * after resuming from a partition hibernation or migration in order
1719  * to maintain the ability to perform live firmware updates. It's not
1720  * catastrophic for this method to be absent or to fail; just log the
1721  * condition in that case.
1722  */
1723 void rtas_activate_firmware(void)
1724 {
1725 	int token = rtas_function_token(RTAS_FN_IBM_ACTIVATE_FIRMWARE);
1726 	int fwrc;
1727 
1728 	if (token == RTAS_UNKNOWN_SERVICE) {
1729 		pr_notice("ibm,activate-firmware method unavailable\n");
1730 		return;
1731 	}
1732 
1733 	mutex_lock(&rtas_ibm_activate_firmware_lock);
1734 
1735 	do {
1736 		fwrc = rtas_call(token, 0, 1, NULL);
1737 	} while (rtas_busy_delay(fwrc));
1738 
1739 	mutex_unlock(&rtas_ibm_activate_firmware_lock);
1740 
1741 	if (fwrc)
1742 		pr_err("ibm,activate-firmware failed (%i)\n", fwrc);
1743 }
1744 
1745 /**
1746  * get_pseries_errorlog() - Find a specific pseries error log in an RTAS
1747  *                          extended event log.
1748  * @log: RTAS error/event log
1749  * @section_id: two character section identifier
1750  *
1751  * Return: A pointer to the specified errorlog or NULL if not found.
1752  */
1753 noinstr struct pseries_errorlog *get_pseries_errorlog(struct rtas_error_log *log,
1754 						      uint16_t section_id)
1755 {
1756 	struct rtas_ext_event_log_v6 *ext_log =
1757 		(struct rtas_ext_event_log_v6 *)log->buffer;
1758 	struct pseries_errorlog *sect;
1759 	unsigned char *p, *log_end;
1760 	uint32_t ext_log_length = rtas_error_extended_log_length(log);
1761 	uint8_t log_format = rtas_ext_event_log_format(ext_log);
1762 	uint32_t company_id = rtas_ext_event_company_id(ext_log);
1763 
1764 	/* Check that we understand the format */
1765 	if (ext_log_length < sizeof(struct rtas_ext_event_log_v6) ||
1766 	    log_format != RTAS_V6EXT_LOG_FORMAT_EVENT_LOG ||
1767 	    company_id != RTAS_V6EXT_COMPANY_ID_IBM)
1768 		return NULL;
1769 
1770 	log_end = log->buffer + ext_log_length;
1771 	p = ext_log->vendor_log;
1772 
1773 	while (p < log_end) {
1774 		sect = (struct pseries_errorlog *)p;
1775 		if (pseries_errorlog_id(sect) == section_id)
1776 			return sect;
1777 		p += pseries_errorlog_length(sect);
1778 	}
1779 
1780 	return NULL;
1781 }
1782 
1783 /*
1784  * The sys_rtas syscall, as originally designed, allows root to pass
1785  * arbitrary physical addresses to RTAS calls. A number of RTAS calls
1786  * can be abused to write to arbitrary memory and do other things that
1787  * are potentially harmful to system integrity, and thus should only
1788  * be used inside the kernel and not exposed to userspace.
1789  *
1790  * All known legitimate users of the sys_rtas syscall will only ever
1791  * pass addresses that fall within the RMO buffer, and use a known
1792  * subset of RTAS calls.
1793  *
1794  * Accordingly, we filter RTAS requests to check that the call is
1795  * permitted, and that provided pointers fall within the RMO buffer.
1796  * If a function is allowed to be invoked via the syscall, then its
1797  * entry in the rtas_functions table points to a rtas_filter that
1798  * describes its constraints, with the indexes of the parameters which
1799  * are expected to contain addresses and sizes of buffers allocated
1800  * inside the RMO buffer.
1801  */
1802 
1803 static bool in_rmo_buf(u32 base, u32 end)
1804 {
1805 	return base >= rtas_rmo_buf &&
1806 		base < (rtas_rmo_buf + RTAS_USER_REGION_SIZE) &&
1807 		base <= end &&
1808 		end >= rtas_rmo_buf &&
1809 		end < (rtas_rmo_buf + RTAS_USER_REGION_SIZE);
1810 }
1811 
1812 static bool block_rtas_call(const struct rtas_function *func, int nargs,
1813 			    struct rtas_args *args)
1814 {
1815 	const struct rtas_filter *f;
1816 	const bool is_platform_dump =
1817 		func == &rtas_function_table[RTAS_FNIDX__IBM_PLATFORM_DUMP];
1818 	const bool is_config_conn =
1819 		func == &rtas_function_table[RTAS_FNIDX__IBM_CONFIGURE_CONNECTOR];
1820 	u32 base, size, end;
1821 
1822 	/*
1823 	 * Only functions with filters attached are allowed.
1824 	 */
1825 	f = func->filter;
1826 	if (!f)
1827 		goto err;
1828 	/*
1829 	 * And some functions aren't allowed on LE.
1830 	 */
1831 	if (IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN) && func->banned_for_syscall_on_le)
1832 		goto err;
1833 
1834 	if (f->buf_idx1 != -1) {
1835 		base = be32_to_cpu(args->args[f->buf_idx1]);
1836 		if (f->size_idx1 != -1)
1837 			size = be32_to_cpu(args->args[f->size_idx1]);
1838 		else if (f->fixed_size)
1839 			size = f->fixed_size;
1840 		else
1841 			size = 1;
1842 
1843 		end = base + size - 1;
1844 
1845 		/*
1846 		 * Special case for ibm,platform-dump - NULL buffer
1847 		 * address is used to indicate end of dump processing
1848 		 */
1849 		if (is_platform_dump && base == 0)
1850 			return false;
1851 
1852 		if (!in_rmo_buf(base, end))
1853 			goto err;
1854 	}
1855 
1856 	if (f->buf_idx2 != -1) {
1857 		base = be32_to_cpu(args->args[f->buf_idx2]);
1858 		if (f->size_idx2 != -1)
1859 			size = be32_to_cpu(args->args[f->size_idx2]);
1860 		else if (f->fixed_size)
1861 			size = f->fixed_size;
1862 		else
1863 			size = 1;
1864 		end = base + size - 1;
1865 
1866 		/*
1867 		 * Special case for ibm,configure-connector where the
1868 		 * address can be 0
1869 		 */
1870 		if (is_config_conn && base == 0)
1871 			return false;
1872 
1873 		if (!in_rmo_buf(base, end))
1874 			goto err;
1875 	}
1876 
1877 	return false;
1878 err:
1879 	pr_err_ratelimited("sys_rtas: RTAS call blocked - exploit attempt?\n");
1880 	pr_err_ratelimited("sys_rtas: %s nargs=%d (called by %s)\n",
1881 			   func->name, nargs, current->comm);
1882 	return true;
1883 }
1884 
1885 /* We assume to be passed big endian arguments */
1886 SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs)
1887 {
1888 	const struct rtas_function *func;
1889 	struct pin_cookie cookie;
1890 	struct rtas_args args;
1891 	unsigned long flags;
1892 	char *buff_copy, *errbuf = NULL;
1893 	int nargs, nret, token;
1894 
1895 	if (!capable(CAP_SYS_ADMIN))
1896 		return -EPERM;
1897 
1898 	if (!rtas.entry)
1899 		return -EINVAL;
1900 
1901 	if (copy_from_user(&args, uargs, 3 * sizeof(u32)) != 0)
1902 		return -EFAULT;
1903 
1904 	nargs = be32_to_cpu(args.nargs);
1905 	nret  = be32_to_cpu(args.nret);
1906 	token = be32_to_cpu(args.token);
1907 
1908 	if (nargs >= ARRAY_SIZE(args.args)
1909 	    || nret > ARRAY_SIZE(args.args)
1910 	    || nargs + nret > ARRAY_SIZE(args.args))
1911 		return -EINVAL;
1912 
1913 	nargs = array_index_nospec(nargs, ARRAY_SIZE(args.args));
1914 	nret = array_index_nospec(nret, ARRAY_SIZE(args.args) - nargs);
1915 
1916 	/* Copy in args. */
1917 	if (copy_from_user(args.args, uargs->args,
1918 			   nargs * sizeof(rtas_arg_t)) != 0)
1919 		return -EFAULT;
1920 
1921 	/*
1922 	 * If this token doesn't correspond to a function the kernel
1923 	 * understands, you're not allowed to call it.
1924 	 */
1925 	func = rtas_token_to_function_untrusted(token);
1926 	if (!func)
1927 		return -EINVAL;
1928 
1929 	args.rets = &args.args[nargs];
1930 	memset(args.rets, 0, nret * sizeof(rtas_arg_t));
1931 
1932 	if (block_rtas_call(func, nargs, &args))
1933 		return -EINVAL;
1934 
1935 	if (token_is_restricted_errinjct(token)) {
1936 		int err;
1937 
1938 		err = security_locked_down(LOCKDOWN_RTAS_ERROR_INJECTION);
1939 		if (err)
1940 			return err;
1941 	}
1942 
1943 	/* Need to handle ibm,suspend_me call specially */
1944 	if (token == rtas_function_token(RTAS_FN_IBM_SUSPEND_ME)) {
1945 
1946 		/*
1947 		 * rtas_ibm_suspend_me assumes the streamid handle is in cpu
1948 		 * endian, or at least the hcall within it requires it.
1949 		 */
1950 		int rc = 0;
1951 		u64 handle = ((u64)be32_to_cpu(args.args[0]) << 32)
1952 		              | be32_to_cpu(args.args[1]);
1953 		rc = rtas_syscall_dispatch_ibm_suspend_me(handle);
1954 		if (rc == -EAGAIN)
1955 			args.rets[0] = cpu_to_be32(RTAS_NOT_SUSPENDABLE);
1956 		else if (rc == -EIO)
1957 			args.rets[0] = cpu_to_be32(-1);
1958 		else if (rc)
1959 			return rc;
1960 		goto copy_return;
1961 	}
1962 
1963 	buff_copy = get_errorlog_buffer();
1964 
1965 	/*
1966 	 * If this function has a mutex assigned to it, we must
1967 	 * acquire it to avoid interleaving with any kernel-based uses
1968 	 * of the same function. Kernel-based sequences acquire the
1969 	 * appropriate mutex explicitly.
1970 	 */
1971 	if (func->lock)
1972 		mutex_lock(func->lock);
1973 
1974 	raw_spin_lock_irqsave(&rtas_lock, flags);
1975 	cookie = lockdep_pin_lock(&rtas_lock);
1976 
1977 	rtas_args = args;
1978 	do_enter_rtas(&rtas_args);
1979 	args = rtas_args;
1980 
1981 	/* A -1 return code indicates that the last command couldn't
1982 	   be completed due to a hardware error. */
1983 	if (be32_to_cpu(args.rets[0]) == -1)
1984 		errbuf = __fetch_rtas_last_error(buff_copy);
1985 
1986 	lockdep_unpin_lock(&rtas_lock, cookie);
1987 	raw_spin_unlock_irqrestore(&rtas_lock, flags);
1988 
1989 	if (func->lock)
1990 		mutex_unlock(func->lock);
1991 
1992 	if (buff_copy) {
1993 		if (errbuf)
1994 			log_error(errbuf, ERR_TYPE_RTAS_LOG, 0);
1995 		kfree(buff_copy);
1996 	}
1997 
1998  copy_return:
1999 	/* Copy out args. */
2000 	if (copy_to_user(uargs->args + nargs,
2001 			 args.args + nargs,
2002 			 nret * sizeof(rtas_arg_t)) != 0)
2003 		return -EFAULT;
2004 
2005 	return 0;
2006 }
2007 
2008 static void __init rtas_function_table_init(void)
2009 {
2010 	struct property *prop;
2011 
2012 	for (size_t i = 0; i < ARRAY_SIZE(rtas_function_table); ++i) {
2013 		struct rtas_function *curr = &rtas_function_table[i];
2014 		struct rtas_function *prior;
2015 		int cmp;
2016 
2017 		curr->token = RTAS_UNKNOWN_SERVICE;
2018 
2019 		if (i == 0)
2020 			continue;
2021 		/*
2022 		 * Ensure table is sorted correctly for binary search
2023 		 * on function names.
2024 		 */
2025 		prior = &rtas_function_table[i - 1];
2026 
2027 		cmp = strcmp(prior->name, curr->name);
2028 		if (cmp < 0)
2029 			continue;
2030 
2031 		if (cmp == 0) {
2032 			pr_err("'%s' has duplicate function table entries\n",
2033 			       curr->name);
2034 		} else {
2035 			pr_err("function table unsorted: '%s' wrongly precedes '%s'\n",
2036 			       prior->name, curr->name);
2037 		}
2038 	}
2039 
2040 	for_each_property_of_node(rtas.dev, prop) {
2041 		struct rtas_function *func;
2042 
2043 		if (prop->length != sizeof(u32))
2044 			continue;
2045 
2046 		func = __rtas_name_to_function(prop->name);
2047 		if (!func)
2048 			continue;
2049 
2050 		func->token = be32_to_cpup((__be32 *)prop->value);
2051 
2052 		pr_debug("function %s has token %u\n", func->name, func->token);
2053 	}
2054 }
2055 
2056 /*
2057  * Call early during boot, before mem init, to retrieve the RTAS
2058  * information from the device-tree and allocate the RMO buffer for userland
2059  * accesses.
2060  */
2061 void __init rtas_initialize(void)
2062 {
2063 	unsigned long rtas_region = RTAS_INSTANTIATE_MAX;
2064 	u32 base, size, entry;
2065 	int no_base, no_size, no_entry;
2066 
2067 	/* Get RTAS dev node and fill up our "rtas" structure with infos
2068 	 * about it.
2069 	 */
2070 	rtas.dev = of_find_node_by_name(NULL, "rtas");
2071 	if (!rtas.dev)
2072 		return;
2073 
2074 	no_base = of_property_read_u32(rtas.dev, "linux,rtas-base", &base);
2075 	no_size = of_property_read_u32(rtas.dev, "rtas-size", &size);
2076 	if (no_base || no_size) {
2077 		of_node_put(rtas.dev);
2078 		rtas.dev = NULL;
2079 		return;
2080 	}
2081 
2082 	rtas.base = base;
2083 	rtas.size = size;
2084 	no_entry = of_property_read_u32(rtas.dev, "linux,rtas-entry", &entry);
2085 	rtas.entry = no_entry ? rtas.base : entry;
2086 
2087 	init_error_log_max();
2088 
2089 	/* Must be called before any function token lookups */
2090 	rtas_function_table_init();
2091 
2092 	/*
2093 	 * Discover this now to avoid a device tree lookup in the
2094 	 * panic path.
2095 	 */
2096 	ibm_extended_os_term = of_property_read_bool(rtas.dev, "ibm,extended-os-term");
2097 
2098 	/* If RTAS was found, allocate the RMO buffer for it and look for
2099 	 * the stop-self token if any
2100 	 */
2101 #ifdef CONFIG_PPC64
2102 	if (firmware_has_feature(FW_FEATURE_LPAR))
2103 		rtas_region = min(ppc64_rma_size, RTAS_INSTANTIATE_MAX);
2104 #endif
2105 	rtas_rmo_buf = memblock_phys_alloc_range(RTAS_USER_REGION_SIZE, PAGE_SIZE,
2106 						 0, rtas_region);
2107 	if (!rtas_rmo_buf)
2108 		panic("ERROR: RTAS: Failed to allocate %lx bytes below %pa\n",
2109 		      PAGE_SIZE, &rtas_region);
2110 
2111 	rtas_work_area_reserve_arena(rtas_region);
2112 }
2113 
2114 int __init early_init_dt_scan_rtas(unsigned long node,
2115 		const char *uname, int depth, void *data)
2116 {
2117 	const u32 *basep, *entryp, *sizep;
2118 
2119 	if (depth != 1 || strcmp(uname, "rtas") != 0)
2120 		return 0;
2121 
2122 	basep  = of_get_flat_dt_prop(node, "linux,rtas-base", NULL);
2123 	entryp = of_get_flat_dt_prop(node, "linux,rtas-entry", NULL);
2124 	sizep  = of_get_flat_dt_prop(node, "rtas-size", NULL);
2125 
2126 #ifdef CONFIG_PPC64
2127 	/* need this feature to decide the crashkernel offset */
2128 	if (of_get_flat_dt_prop(node, "ibm,hypertas-functions", NULL))
2129 		powerpc_firmware_features |= FW_FEATURE_LPAR;
2130 #endif
2131 
2132 	if (basep && entryp && sizep) {
2133 		rtas.base = *basep;
2134 		rtas.entry = *entryp;
2135 		rtas.size = *sizep;
2136 	}
2137 
2138 #ifdef CONFIG_UDBG_RTAS_CONSOLE
2139 	basep = of_get_flat_dt_prop(node, "put-term-char", NULL);
2140 	if (basep)
2141 		rtas_putchar_token = *basep;
2142 
2143 	basep = of_get_flat_dt_prop(node, "get-term-char", NULL);
2144 	if (basep)
2145 		rtas_getchar_token = *basep;
2146 
2147 	if (rtas_putchar_token != RTAS_UNKNOWN_SERVICE &&
2148 	    rtas_getchar_token != RTAS_UNKNOWN_SERVICE)
2149 		udbg_init_rtas_console();
2150 
2151 #endif
2152 
2153 	/* break now */
2154 	return 1;
2155 }
2156 
2157 static DEFINE_RAW_SPINLOCK(timebase_lock);
2158 static u64 timebase = 0;
2159 
2160 void rtas_give_timebase(void)
2161 {
2162 	unsigned long flags;
2163 
2164 	raw_spin_lock_irqsave(&timebase_lock, flags);
2165 	hard_irq_disable();
2166 	rtas_call(rtas_function_token(RTAS_FN_FREEZE_TIME_BASE), 0, 1, NULL);
2167 	timebase = get_tb();
2168 	raw_spin_unlock(&timebase_lock);
2169 
2170 	while (timebase)
2171 		barrier();
2172 	rtas_call(rtas_function_token(RTAS_FN_THAW_TIME_BASE), 0, 1, NULL);
2173 	local_irq_restore(flags);
2174 }
2175 
2176 void rtas_take_timebase(void)
2177 {
2178 	while (!timebase)
2179 		barrier();
2180 	raw_spin_lock(&timebase_lock);
2181 	set_tb(timebase >> 32, timebase & 0xffffffff);
2182 	timebase = 0;
2183 	raw_spin_unlock(&timebase_lock);
2184 }
2185