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 #include <linux/stdarg.h>
11 #include <linux/kernel.h>
12 #include <linux/types.h>
13 #include <linux/spinlock.h>
14 #include <linux/export.h>
15 #include <linux/init.h>
16 #include <linux/capability.h>
17 #include <linux/delay.h>
18 #include <linux/cpu.h>
19 #include <linux/sched.h>
20 #include <linux/smp.h>
21 #include <linux/completion.h>
22 #include <linux/cpumask.h>
23 #include <linux/memblock.h>
24 #include <linux/slab.h>
25 #include <linux/reboot.h>
26 #include <linux/security.h>
27 #include <linux/syscalls.h>
28 #include <linux/of.h>
29 #include <linux/of_fdt.h>
30
31 #include <asm/interrupt.h>
32 #include <asm/rtas.h>
33 #include <asm/hvcall.h>
34 #include <asm/machdep.h>
35 #include <asm/firmware.h>
36 #include <asm/page.h>
37 #include <asm/param.h>
38 #include <asm/delay.h>
39 #include <linux/uaccess.h>
40 #include <asm/udbg.h>
41 #include <asm/syscalls.h>
42 #include <asm/smp.h>
43 #include <linux/atomic.h>
44 #include <asm/time.h>
45 #include <asm/mmu.h>
46 #include <asm/topology.h>
47
48 /* This is here deliberately so it's only used in this file */
49 void enter_rtas(unsigned long);
50
do_enter_rtas(unsigned long args)51 static inline void do_enter_rtas(unsigned long args)
52 {
53 unsigned long msr;
54
55 /*
56 * Make sure MSR[RI] is currently enabled as it will be forced later
57 * in enter_rtas.
58 */
59 msr = mfmsr();
60 BUG_ON(!(msr & MSR_RI));
61
62 BUG_ON(!irqs_disabled());
63
64 hard_irq_disable(); /* Ensure MSR[EE] is disabled on PPC64 */
65
66 enter_rtas(args);
67
68 srr_regs_clobbered(); /* rtas uses SRRs, invalidate */
69 }
70
71 struct rtas_t rtas = {
72 .lock = __ARCH_SPIN_LOCK_UNLOCKED
73 };
74 EXPORT_SYMBOL(rtas);
75
76 DEFINE_SPINLOCK(rtas_data_buf_lock);
77 EXPORT_SYMBOL(rtas_data_buf_lock);
78
79 char rtas_data_buf[RTAS_DATA_BUF_SIZE] __cacheline_aligned;
80 EXPORT_SYMBOL(rtas_data_buf);
81
82 unsigned long rtas_rmo_buf;
83
84 /*
85 * If non-NULL, this gets called when the kernel terminates.
86 * This is done like this so rtas_flash can be a module.
87 */
88 void (*rtas_flash_term_hook)(int);
89 EXPORT_SYMBOL(rtas_flash_term_hook);
90
91 /* RTAS use home made raw locking instead of spin_lock_irqsave
92 * because those can be called from within really nasty contexts
93 * such as having the timebase stopped which would lockup with
94 * normal locks and spinlock debugging enabled
95 */
lock_rtas(void)96 static unsigned long lock_rtas(void)
97 {
98 unsigned long flags;
99
100 local_irq_save(flags);
101 preempt_disable();
102 arch_spin_lock(&rtas.lock);
103 return flags;
104 }
105
unlock_rtas(unsigned long flags)106 static void unlock_rtas(unsigned long flags)
107 {
108 arch_spin_unlock(&rtas.lock);
109 local_irq_restore(flags);
110 preempt_enable();
111 }
112
113 /*
114 * call_rtas_display_status and call_rtas_display_status_delay
115 * are designed only for very early low-level debugging, which
116 * is why the token is hard-coded to 10.
117 */
call_rtas_display_status(unsigned char c)118 static void call_rtas_display_status(unsigned char c)
119 {
120 unsigned long s;
121
122 if (!rtas.base)
123 return;
124
125 s = lock_rtas();
126 rtas_call_unlocked(&rtas.args, 10, 1, 1, NULL, c);
127 unlock_rtas(s);
128 }
129
call_rtas_display_status_delay(char c)130 static void call_rtas_display_status_delay(char c)
131 {
132 static int pending_newline = 0; /* did last write end with unprinted newline? */
133 static int width = 16;
134
135 if (c == '\n') {
136 while (width-- > 0)
137 call_rtas_display_status(' ');
138 width = 16;
139 mdelay(500);
140 pending_newline = 1;
141 } else {
142 if (pending_newline) {
143 call_rtas_display_status('\r');
144 call_rtas_display_status('\n');
145 }
146 pending_newline = 0;
147 if (width--) {
148 call_rtas_display_status(c);
149 udelay(10000);
150 }
151 }
152 }
153
udbg_init_rtas_panel(void)154 void __init udbg_init_rtas_panel(void)
155 {
156 udbg_putc = call_rtas_display_status_delay;
157 }
158
159 #ifdef CONFIG_UDBG_RTAS_CONSOLE
160
161 /* If you think you're dying before early_init_dt_scan_rtas() does its
162 * work, you can hard code the token values for your firmware here and
163 * hardcode rtas.base/entry etc.
164 */
165 static unsigned int rtas_putchar_token = RTAS_UNKNOWN_SERVICE;
166 static unsigned int rtas_getchar_token = RTAS_UNKNOWN_SERVICE;
167
udbg_rtascon_putc(char c)168 static void udbg_rtascon_putc(char c)
169 {
170 int tries;
171
172 if (!rtas.base)
173 return;
174
175 /* Add CRs before LFs */
176 if (c == '\n')
177 udbg_rtascon_putc('\r');
178
179 /* if there is more than one character to be displayed, wait a bit */
180 for (tries = 0; tries < 16; tries++) {
181 if (rtas_call(rtas_putchar_token, 1, 1, NULL, c) == 0)
182 break;
183 udelay(1000);
184 }
185 }
186
udbg_rtascon_getc_poll(void)187 static int udbg_rtascon_getc_poll(void)
188 {
189 int c;
190
191 if (!rtas.base)
192 return -1;
193
194 if (rtas_call(rtas_getchar_token, 0, 2, &c))
195 return -1;
196
197 return c;
198 }
199
udbg_rtascon_getc(void)200 static int udbg_rtascon_getc(void)
201 {
202 int c;
203
204 while ((c = udbg_rtascon_getc_poll()) == -1)
205 ;
206
207 return c;
208 }
209
210
udbg_init_rtas_console(void)211 void __init udbg_init_rtas_console(void)
212 {
213 udbg_putc = udbg_rtascon_putc;
214 udbg_getc = udbg_rtascon_getc;
215 udbg_getc_poll = udbg_rtascon_getc_poll;
216 }
217 #endif /* CONFIG_UDBG_RTAS_CONSOLE */
218
rtas_progress(char * s,unsigned short hex)219 void rtas_progress(char *s, unsigned short hex)
220 {
221 struct device_node *root;
222 int width;
223 const __be32 *p;
224 char *os;
225 static int display_character, set_indicator;
226 static int display_width, display_lines, form_feed;
227 static const int *row_width;
228 static DEFINE_SPINLOCK(progress_lock);
229 static int current_line;
230 static int pending_newline = 0; /* did last write end with unprinted newline? */
231
232 if (!rtas.base)
233 return;
234
235 if (display_width == 0) {
236 display_width = 0x10;
237 if ((root = of_find_node_by_path("/rtas"))) {
238 if ((p = of_get_property(root,
239 "ibm,display-line-length", NULL)))
240 display_width = be32_to_cpu(*p);
241 if ((p = of_get_property(root,
242 "ibm,form-feed", NULL)))
243 form_feed = be32_to_cpu(*p);
244 if ((p = of_get_property(root,
245 "ibm,display-number-of-lines", NULL)))
246 display_lines = be32_to_cpu(*p);
247 row_width = of_get_property(root,
248 "ibm,display-truncation-length", NULL);
249 of_node_put(root);
250 }
251 display_character = rtas_token("display-character");
252 set_indicator = rtas_token("set-indicator");
253 }
254
255 if (display_character == RTAS_UNKNOWN_SERVICE) {
256 /* use hex display if available */
257 if (set_indicator != RTAS_UNKNOWN_SERVICE)
258 rtas_call(set_indicator, 3, 1, NULL, 6, 0, hex);
259 return;
260 }
261
262 spin_lock(&progress_lock);
263
264 /*
265 * Last write ended with newline, but we didn't print it since
266 * it would just clear the bottom line of output. Print it now
267 * instead.
268 *
269 * If no newline is pending and form feed is supported, clear the
270 * display with a form feed; otherwise, print a CR to start output
271 * at the beginning of the line.
272 */
273 if (pending_newline) {
274 rtas_call(display_character, 1, 1, NULL, '\r');
275 rtas_call(display_character, 1, 1, NULL, '\n');
276 pending_newline = 0;
277 } else {
278 current_line = 0;
279 if (form_feed)
280 rtas_call(display_character, 1, 1, NULL,
281 (char)form_feed);
282 else
283 rtas_call(display_character, 1, 1, NULL, '\r');
284 }
285
286 if (row_width)
287 width = row_width[current_line];
288 else
289 width = display_width;
290 os = s;
291 while (*os) {
292 if (*os == '\n' || *os == '\r') {
293 /* If newline is the last character, save it
294 * until next call to avoid bumping up the
295 * display output.
296 */
297 if (*os == '\n' && !os[1]) {
298 pending_newline = 1;
299 current_line++;
300 if (current_line > display_lines-1)
301 current_line = display_lines-1;
302 spin_unlock(&progress_lock);
303 return;
304 }
305
306 /* RTAS wants CR-LF, not just LF */
307
308 if (*os == '\n') {
309 rtas_call(display_character, 1, 1, NULL, '\r');
310 rtas_call(display_character, 1, 1, NULL, '\n');
311 } else {
312 /* CR might be used to re-draw a line, so we'll
313 * leave it alone and not add LF.
314 */
315 rtas_call(display_character, 1, 1, NULL, *os);
316 }
317
318 if (row_width)
319 width = row_width[current_line];
320 else
321 width = display_width;
322 } else {
323 width--;
324 rtas_call(display_character, 1, 1, NULL, *os);
325 }
326
327 os++;
328
329 /* if we overwrite the screen length */
330 if (width <= 0)
331 while ((*os != 0) && (*os != '\n') && (*os != '\r'))
332 os++;
333 }
334
335 spin_unlock(&progress_lock);
336 }
337 EXPORT_SYMBOL(rtas_progress); /* needed by rtas_flash module */
338
rtas_token(const char * service)339 int rtas_token(const char *service)
340 {
341 const __be32 *tokp;
342 if (rtas.dev == NULL)
343 return RTAS_UNKNOWN_SERVICE;
344 tokp = of_get_property(rtas.dev, service, NULL);
345 return tokp ? be32_to_cpu(*tokp) : RTAS_UNKNOWN_SERVICE;
346 }
347 EXPORT_SYMBOL(rtas_token);
348
rtas_service_present(const char * service)349 int rtas_service_present(const char *service)
350 {
351 return rtas_token(service) != RTAS_UNKNOWN_SERVICE;
352 }
353 EXPORT_SYMBOL(rtas_service_present);
354
355 #ifdef CONFIG_RTAS_ERROR_LOGGING
356 /*
357 * Return the firmware-specified size of the error log buffer
358 * for all rtas calls that require an error buffer argument.
359 * This includes 'check-exception' and 'rtas-last-error'.
360 */
rtas_get_error_log_max(void)361 int rtas_get_error_log_max(void)
362 {
363 static int rtas_error_log_max;
364 if (rtas_error_log_max)
365 return rtas_error_log_max;
366
367 rtas_error_log_max = rtas_token ("rtas-error-log-max");
368 if ((rtas_error_log_max == RTAS_UNKNOWN_SERVICE) ||
369 (rtas_error_log_max > RTAS_ERROR_LOG_MAX)) {
370 printk (KERN_WARNING "RTAS: bad log buffer size %d\n",
371 rtas_error_log_max);
372 rtas_error_log_max = RTAS_ERROR_LOG_MAX;
373 }
374 return rtas_error_log_max;
375 }
376 EXPORT_SYMBOL(rtas_get_error_log_max);
377
378
379 static char rtas_err_buf[RTAS_ERROR_LOG_MAX];
380 static int rtas_last_error_token;
381
382 /** Return a copy of the detailed error text associated with the
383 * most recent failed call to rtas. Because the error text
384 * might go stale if there are any other intervening rtas calls,
385 * this routine must be called atomically with whatever produced
386 * the error (i.e. with rtas.lock still held from the previous call).
387 */
__fetch_rtas_last_error(char * altbuf)388 static char *__fetch_rtas_last_error(char *altbuf)
389 {
390 struct rtas_args err_args, save_args;
391 u32 bufsz;
392 char *buf = NULL;
393
394 if (rtas_last_error_token == -1)
395 return NULL;
396
397 bufsz = rtas_get_error_log_max();
398
399 err_args.token = cpu_to_be32(rtas_last_error_token);
400 err_args.nargs = cpu_to_be32(2);
401 err_args.nret = cpu_to_be32(1);
402 err_args.args[0] = cpu_to_be32(__pa(rtas_err_buf));
403 err_args.args[1] = cpu_to_be32(bufsz);
404 err_args.args[2] = 0;
405
406 save_args = rtas.args;
407 rtas.args = err_args;
408
409 do_enter_rtas(__pa(&rtas.args));
410
411 err_args = rtas.args;
412 rtas.args = save_args;
413
414 /* Log the error in the unlikely case that there was one. */
415 if (unlikely(err_args.args[2] == 0)) {
416 if (altbuf) {
417 buf = altbuf;
418 } else {
419 buf = rtas_err_buf;
420 if (slab_is_available())
421 buf = kmalloc(RTAS_ERROR_LOG_MAX, GFP_ATOMIC);
422 }
423 if (buf)
424 memcpy(buf, rtas_err_buf, RTAS_ERROR_LOG_MAX);
425 }
426
427 return buf;
428 }
429
430 #define get_errorlog_buffer() kmalloc(RTAS_ERROR_LOG_MAX, GFP_KERNEL)
431
432 #else /* CONFIG_RTAS_ERROR_LOGGING */
433 #define __fetch_rtas_last_error(x) NULL
434 #define get_errorlog_buffer() NULL
435 #endif
436
437
438 static void
va_rtas_call_unlocked(struct rtas_args * args,int token,int nargs,int nret,va_list list)439 va_rtas_call_unlocked(struct rtas_args *args, int token, int nargs, int nret,
440 va_list list)
441 {
442 int i;
443
444 args->token = cpu_to_be32(token);
445 args->nargs = cpu_to_be32(nargs);
446 args->nret = cpu_to_be32(nret);
447 args->rets = &(args->args[nargs]);
448
449 for (i = 0; i < nargs; ++i)
450 args->args[i] = cpu_to_be32(va_arg(list, __u32));
451
452 for (i = 0; i < nret; ++i)
453 args->rets[i] = 0;
454
455 do_enter_rtas(__pa(args));
456 }
457
rtas_call_unlocked(struct rtas_args * args,int token,int nargs,int nret,...)458 void rtas_call_unlocked(struct rtas_args *args, int token, int nargs, int nret, ...)
459 {
460 va_list list;
461
462 va_start(list, nret);
463 va_rtas_call_unlocked(args, token, nargs, nret, list);
464 va_end(list);
465 }
466
467 static int ibm_open_errinjct_token;
468 static int ibm_errinjct_token;
469
rtas_call(int token,int nargs,int nret,int * outputs,...)470 int rtas_call(int token, int nargs, int nret, int *outputs, ...)
471 {
472 va_list list;
473 int i;
474 unsigned long s;
475 struct rtas_args *rtas_args;
476 char *buff_copy = NULL;
477 int ret;
478
479 if (!rtas.entry || token == RTAS_UNKNOWN_SERVICE)
480 return -1;
481
482 if (token == ibm_open_errinjct_token || token == ibm_errinjct_token) {
483 /*
484 * It would be nicer to not discard the error value
485 * from security_locked_down(), but callers expect an
486 * RTAS status, not an errno.
487 */
488 if (security_locked_down(LOCKDOWN_RTAS_ERROR_INJECTION))
489 return -1;
490 }
491
492 if ((mfmsr() & (MSR_IR|MSR_DR)) != (MSR_IR|MSR_DR)) {
493 WARN_ON_ONCE(1);
494 return -1;
495 }
496
497 s = lock_rtas();
498
499 /* We use the global rtas args buffer */
500 rtas_args = &rtas.args;
501
502 va_start(list, outputs);
503 va_rtas_call_unlocked(rtas_args, token, nargs, nret, list);
504 va_end(list);
505
506 /* A -1 return code indicates that the last command couldn't
507 be completed due to a hardware error. */
508 if (be32_to_cpu(rtas_args->rets[0]) == -1)
509 buff_copy = __fetch_rtas_last_error(NULL);
510
511 if (nret > 1 && outputs != NULL)
512 for (i = 0; i < nret-1; ++i)
513 outputs[i] = be32_to_cpu(rtas_args->rets[i+1]);
514 ret = (nret > 0)? be32_to_cpu(rtas_args->rets[0]): 0;
515
516 unlock_rtas(s);
517
518 if (buff_copy) {
519 log_error(buff_copy, ERR_TYPE_RTAS_LOG, 0);
520 if (slab_is_available())
521 kfree(buff_copy);
522 }
523 return ret;
524 }
525 EXPORT_SYMBOL(rtas_call);
526
527 /**
528 * rtas_busy_delay_time() - From an RTAS status value, calculate the
529 * suggested delay time in milliseconds.
530 *
531 * @status: a value returned from rtas_call() or similar APIs which return
532 * the status of a RTAS function call.
533 *
534 * Context: Any context.
535 *
536 * Return:
537 * * 100000 - If @status is 9905.
538 * * 10000 - If @status is 9904.
539 * * 1000 - If @status is 9903.
540 * * 100 - If @status is 9902.
541 * * 10 - If @status is 9901.
542 * * 1 - If @status is either 9900 or -2. This is "wrong" for -2, but
543 * some callers depend on this behavior, and the worst outcome
544 * is that they will delay for longer than necessary.
545 * * 0 - If @status is not a busy or extended delay value.
546 */
rtas_busy_delay_time(int status)547 unsigned int rtas_busy_delay_time(int status)
548 {
549 int order;
550 unsigned int ms = 0;
551
552 if (status == RTAS_BUSY) {
553 ms = 1;
554 } else if (status >= RTAS_EXTENDED_DELAY_MIN &&
555 status <= RTAS_EXTENDED_DELAY_MAX) {
556 order = status - RTAS_EXTENDED_DELAY_MIN;
557 for (ms = 1; order > 0; order--)
558 ms *= 10;
559 }
560
561 return ms;
562 }
563 EXPORT_SYMBOL(rtas_busy_delay_time);
564
565 /**
566 * rtas_busy_delay() - helper for RTAS busy and extended delay statuses
567 *
568 * @status: a value returned from rtas_call() or similar APIs which return
569 * the status of a RTAS function call.
570 *
571 * Context: Process context. May sleep or schedule.
572 *
573 * Return:
574 * * true - @status is RTAS_BUSY or an extended delay hint. The
575 * caller may assume that the CPU has been yielded if necessary,
576 * and that an appropriate delay for @status has elapsed.
577 * Generally the caller should reattempt the RTAS call which
578 * yielded @status.
579 *
580 * * false - @status is not @RTAS_BUSY nor an extended delay hint. The
581 * caller is responsible for handling @status.
582 */
rtas_busy_delay(int status)583 bool rtas_busy_delay(int status)
584 {
585 unsigned int ms;
586 bool ret;
587
588 switch (status) {
589 case RTAS_EXTENDED_DELAY_MIN...RTAS_EXTENDED_DELAY_MAX:
590 ret = true;
591 ms = rtas_busy_delay_time(status);
592 /*
593 * The extended delay hint can be as high as 100 seconds.
594 * Surely any function returning such a status is either
595 * buggy or isn't going to be significantly slowed by us
596 * polling at 1HZ. Clamp the sleep time to one second.
597 */
598 ms = clamp(ms, 1U, 1000U);
599 /*
600 * The delay hint is an order-of-magnitude suggestion, not
601 * a minimum. It is fine, possibly even advantageous, for
602 * us to pause for less time than hinted. For small values,
603 * use usleep_range() to ensure we don't sleep much longer
604 * than actually needed.
605 *
606 * See Documentation/timers/timers-howto.rst for
607 * explanation of the threshold used here. In effect we use
608 * usleep_range() for 9900 and 9901, msleep() for
609 * 9902-9905.
610 */
611 if (ms <= 20)
612 usleep_range(ms * 100, ms * 1000);
613 else
614 msleep(ms);
615 break;
616 case RTAS_BUSY:
617 ret = true;
618 /*
619 * We should call again immediately if there's no other
620 * work to do.
621 */
622 cond_resched();
623 break;
624 default:
625 ret = false;
626 /*
627 * Not a busy or extended delay status; the caller should
628 * handle @status itself. Ensure we warn on misuses in
629 * atomic context regardless.
630 */
631 might_sleep();
632 break;
633 }
634
635 return ret;
636 }
637 EXPORT_SYMBOL(rtas_busy_delay);
638
rtas_error_rc(int rtas_rc)639 static int rtas_error_rc(int rtas_rc)
640 {
641 int rc;
642
643 switch (rtas_rc) {
644 case -1: /* Hardware Error */
645 rc = -EIO;
646 break;
647 case -3: /* Bad indicator/domain/etc */
648 rc = -EINVAL;
649 break;
650 case -9000: /* Isolation error */
651 rc = -EFAULT;
652 break;
653 case -9001: /* Outstanding TCE/PTE */
654 rc = -EEXIST;
655 break;
656 case -9002: /* No usable slot */
657 rc = -ENODEV;
658 break;
659 default:
660 printk(KERN_ERR "%s: unexpected RTAS error %d\n",
661 __func__, rtas_rc);
662 rc = -ERANGE;
663 break;
664 }
665 return rc;
666 }
667
rtas_get_power_level(int powerdomain,int * level)668 int rtas_get_power_level(int powerdomain, int *level)
669 {
670 int token = rtas_token("get-power-level");
671 int rc;
672
673 if (token == RTAS_UNKNOWN_SERVICE)
674 return -ENOENT;
675
676 while ((rc = rtas_call(token, 1, 2, level, powerdomain)) == RTAS_BUSY)
677 udelay(1);
678
679 if (rc < 0)
680 return rtas_error_rc(rc);
681 return rc;
682 }
683 EXPORT_SYMBOL(rtas_get_power_level);
684
rtas_set_power_level(int powerdomain,int level,int * setlevel)685 int rtas_set_power_level(int powerdomain, int level, int *setlevel)
686 {
687 int token = rtas_token("set-power-level");
688 int rc;
689
690 if (token == RTAS_UNKNOWN_SERVICE)
691 return -ENOENT;
692
693 do {
694 rc = rtas_call(token, 2, 2, setlevel, powerdomain, level);
695 } while (rtas_busy_delay(rc));
696
697 if (rc < 0)
698 return rtas_error_rc(rc);
699 return rc;
700 }
701 EXPORT_SYMBOL(rtas_set_power_level);
702
rtas_get_sensor(int sensor,int index,int * state)703 int rtas_get_sensor(int sensor, int index, int *state)
704 {
705 int token = rtas_token("get-sensor-state");
706 int rc;
707
708 if (token == RTAS_UNKNOWN_SERVICE)
709 return -ENOENT;
710
711 do {
712 rc = rtas_call(token, 2, 2, state, sensor, index);
713 } while (rtas_busy_delay(rc));
714
715 if (rc < 0)
716 return rtas_error_rc(rc);
717 return rc;
718 }
719 EXPORT_SYMBOL(rtas_get_sensor);
720
rtas_get_sensor_fast(int sensor,int index,int * state)721 int rtas_get_sensor_fast(int sensor, int index, int *state)
722 {
723 int token = rtas_token("get-sensor-state");
724 int rc;
725
726 if (token == RTAS_UNKNOWN_SERVICE)
727 return -ENOENT;
728
729 rc = rtas_call(token, 2, 2, state, sensor, index);
730 WARN_ON(rc == RTAS_BUSY || (rc >= RTAS_EXTENDED_DELAY_MIN &&
731 rc <= RTAS_EXTENDED_DELAY_MAX));
732
733 if (rc < 0)
734 return rtas_error_rc(rc);
735 return rc;
736 }
737
rtas_indicator_present(int token,int * maxindex)738 bool rtas_indicator_present(int token, int *maxindex)
739 {
740 int proplen, count, i;
741 const struct indicator_elem {
742 __be32 token;
743 __be32 maxindex;
744 } *indicators;
745
746 indicators = of_get_property(rtas.dev, "rtas-indicators", &proplen);
747 if (!indicators)
748 return false;
749
750 count = proplen / sizeof(struct indicator_elem);
751
752 for (i = 0; i < count; i++) {
753 if (__be32_to_cpu(indicators[i].token) != token)
754 continue;
755 if (maxindex)
756 *maxindex = __be32_to_cpu(indicators[i].maxindex);
757 return true;
758 }
759
760 return false;
761 }
762 EXPORT_SYMBOL(rtas_indicator_present);
763
rtas_set_indicator(int indicator,int index,int new_value)764 int rtas_set_indicator(int indicator, int index, int new_value)
765 {
766 int token = rtas_token("set-indicator");
767 int rc;
768
769 if (token == RTAS_UNKNOWN_SERVICE)
770 return -ENOENT;
771
772 do {
773 rc = rtas_call(token, 3, 1, NULL, indicator, index, new_value);
774 } while (rtas_busy_delay(rc));
775
776 if (rc < 0)
777 return rtas_error_rc(rc);
778 return rc;
779 }
780 EXPORT_SYMBOL(rtas_set_indicator);
781
782 /*
783 * Ignoring RTAS extended delay
784 */
rtas_set_indicator_fast(int indicator,int index,int new_value)785 int rtas_set_indicator_fast(int indicator, int index, int new_value)
786 {
787 int rc;
788 int token = rtas_token("set-indicator");
789
790 if (token == RTAS_UNKNOWN_SERVICE)
791 return -ENOENT;
792
793 rc = rtas_call(token, 3, 1, NULL, indicator, index, new_value);
794
795 WARN_ON(rc == RTAS_BUSY || (rc >= RTAS_EXTENDED_DELAY_MIN &&
796 rc <= RTAS_EXTENDED_DELAY_MAX));
797
798 if (rc < 0)
799 return rtas_error_rc(rc);
800
801 return rc;
802 }
803
804 /**
805 * rtas_ibm_suspend_me() - Call ibm,suspend-me to suspend the LPAR.
806 *
807 * @fw_status: RTAS call status will be placed here if not NULL.
808 *
809 * rtas_ibm_suspend_me() should be called only on a CPU which has
810 * received H_CONTINUE from the H_JOIN hcall. All other active CPUs
811 * should be waiting to return from H_JOIN.
812 *
813 * rtas_ibm_suspend_me() may suspend execution of the OS
814 * indefinitely. Callers should take appropriate measures upon return, such as
815 * resetting watchdog facilities.
816 *
817 * Callers may choose to retry this call if @fw_status is
818 * %RTAS_THREADS_ACTIVE.
819 *
820 * Return:
821 * 0 - The partition has resumed from suspend, possibly after
822 * migration to a different host.
823 * -ECANCELED - The operation was aborted.
824 * -EAGAIN - There were other CPUs not in H_JOIN at the time of the call.
825 * -EBUSY - Some other condition prevented the suspend from succeeding.
826 * -EIO - Hardware/platform error.
827 */
rtas_ibm_suspend_me(int * fw_status)828 int rtas_ibm_suspend_me(int *fw_status)
829 {
830 int fwrc;
831 int ret;
832
833 fwrc = rtas_call(rtas_token("ibm,suspend-me"), 0, 1, NULL);
834
835 switch (fwrc) {
836 case 0:
837 ret = 0;
838 break;
839 case RTAS_SUSPEND_ABORTED:
840 ret = -ECANCELED;
841 break;
842 case RTAS_THREADS_ACTIVE:
843 ret = -EAGAIN;
844 break;
845 case RTAS_NOT_SUSPENDABLE:
846 case RTAS_OUTSTANDING_COPROC:
847 ret = -EBUSY;
848 break;
849 case -1:
850 default:
851 ret = -EIO;
852 break;
853 }
854
855 if (fw_status)
856 *fw_status = fwrc;
857
858 return ret;
859 }
860
rtas_restart(char * cmd)861 void __noreturn rtas_restart(char *cmd)
862 {
863 if (rtas_flash_term_hook)
864 rtas_flash_term_hook(SYS_RESTART);
865 printk("RTAS system-reboot returned %d\n",
866 rtas_call(rtas_token("system-reboot"), 0, 1, NULL));
867 for (;;);
868 }
869
rtas_power_off(void)870 void rtas_power_off(void)
871 {
872 if (rtas_flash_term_hook)
873 rtas_flash_term_hook(SYS_POWER_OFF);
874 /* allow power on only with power button press */
875 printk("RTAS power-off returned %d\n",
876 rtas_call(rtas_token("power-off"), 2, 1, NULL, -1, -1));
877 for (;;);
878 }
879
rtas_halt(void)880 void __noreturn rtas_halt(void)
881 {
882 if (rtas_flash_term_hook)
883 rtas_flash_term_hook(SYS_HALT);
884 /* allow power on only with power button press */
885 printk("RTAS power-off returned %d\n",
886 rtas_call(rtas_token("power-off"), 2, 1, NULL, -1, -1));
887 for (;;);
888 }
889
890 /* Must be in the RMO region, so we place it here */
891 static char rtas_os_term_buf[2048];
892 static s32 ibm_os_term_token = RTAS_UNKNOWN_SERVICE;
893
rtas_os_term(char * str)894 void rtas_os_term(char *str)
895 {
896 int status;
897
898 /*
899 * Firmware with the ibm,extended-os-term property is guaranteed
900 * to always return from an ibm,os-term call. Earlier versions without
901 * this property may terminate the partition which we want to avoid
902 * since it interferes with panic_timeout.
903 */
904 if (ibm_os_term_token == RTAS_UNKNOWN_SERVICE)
905 return;
906
907 snprintf(rtas_os_term_buf, 2048, "OS panic: %s", str);
908
909 /*
910 * Keep calling as long as RTAS returns a "try again" status,
911 * but don't use rtas_busy_delay(), which potentially
912 * schedules.
913 */
914 do {
915 status = rtas_call(ibm_os_term_token, 1, 1, NULL,
916 __pa(rtas_os_term_buf));
917 } while (rtas_busy_delay_time(status));
918
919 if (status != 0)
920 printk(KERN_EMERG "ibm,os-term call failed %d\n", status);
921 }
922
923 /**
924 * rtas_activate_firmware() - Activate a new version of firmware.
925 *
926 * Context: This function may sleep.
927 *
928 * Activate a new version of partition firmware. The OS must call this
929 * after resuming from a partition hibernation or migration in order
930 * to maintain the ability to perform live firmware updates. It's not
931 * catastrophic for this method to be absent or to fail; just log the
932 * condition in that case.
933 */
rtas_activate_firmware(void)934 void rtas_activate_firmware(void)
935 {
936 int token;
937 int fwrc;
938
939 token = rtas_token("ibm,activate-firmware");
940 if (token == RTAS_UNKNOWN_SERVICE) {
941 pr_notice("ibm,activate-firmware method unavailable\n");
942 return;
943 }
944
945 do {
946 fwrc = rtas_call(token, 0, 1, NULL);
947 } while (rtas_busy_delay(fwrc));
948
949 if (fwrc)
950 pr_err("ibm,activate-firmware failed (%i)\n", fwrc);
951 }
952
953 /**
954 * get_pseries_errorlog() - Find a specific pseries error log in an RTAS
955 * extended event log.
956 * @log: RTAS error/event log
957 * @section_id: two character section identifier
958 *
959 * Return: A pointer to the specified errorlog or NULL if not found.
960 */
get_pseries_errorlog(struct rtas_error_log * log,uint16_t section_id)961 noinstr struct pseries_errorlog *get_pseries_errorlog(struct rtas_error_log *log,
962 uint16_t section_id)
963 {
964 struct rtas_ext_event_log_v6 *ext_log =
965 (struct rtas_ext_event_log_v6 *)log->buffer;
966 struct pseries_errorlog *sect;
967 unsigned char *p, *log_end;
968 uint32_t ext_log_length = rtas_error_extended_log_length(log);
969 uint8_t log_format = rtas_ext_event_log_format(ext_log);
970 uint32_t company_id = rtas_ext_event_company_id(ext_log);
971
972 /* Check that we understand the format */
973 if (ext_log_length < sizeof(struct rtas_ext_event_log_v6) ||
974 log_format != RTAS_V6EXT_LOG_FORMAT_EVENT_LOG ||
975 company_id != RTAS_V6EXT_COMPANY_ID_IBM)
976 return NULL;
977
978 log_end = log->buffer + ext_log_length;
979 p = ext_log->vendor_log;
980
981 while (p < log_end) {
982 sect = (struct pseries_errorlog *)p;
983 if (pseries_errorlog_id(sect) == section_id)
984 return sect;
985 p += pseries_errorlog_length(sect);
986 }
987
988 return NULL;
989 }
990
991 #ifdef CONFIG_PPC_RTAS_FILTER
992
993 /*
994 * The sys_rtas syscall, as originally designed, allows root to pass
995 * arbitrary physical addresses to RTAS calls. A number of RTAS calls
996 * can be abused to write to arbitrary memory and do other things that
997 * are potentially harmful to system integrity, and thus should only
998 * be used inside the kernel and not exposed to userspace.
999 *
1000 * All known legitimate users of the sys_rtas syscall will only ever
1001 * pass addresses that fall within the RMO buffer, and use a known
1002 * subset of RTAS calls.
1003 *
1004 * Accordingly, we filter RTAS requests to check that the call is
1005 * permitted, and that provided pointers fall within the RMO buffer.
1006 * The rtas_filters list contains an entry for each permitted call,
1007 * with the indexes of the parameters which are expected to contain
1008 * addresses and sizes of buffers allocated inside the RMO buffer.
1009 */
1010 struct rtas_filter {
1011 const char *name;
1012 int token;
1013 /* Indexes into the args buffer, -1 if not used */
1014 int buf_idx1;
1015 int size_idx1;
1016 int buf_idx2;
1017 int size_idx2;
1018
1019 int fixed_size;
1020 };
1021
1022 static struct rtas_filter rtas_filters[] __ro_after_init = {
1023 { "ibm,activate-firmware", -1, -1, -1, -1, -1 },
1024 { "ibm,configure-connector", -1, 0, -1, 1, -1, 4096 }, /* Special cased */
1025 { "display-character", -1, -1, -1, -1, -1 },
1026 { "ibm,display-message", -1, 0, -1, -1, -1 },
1027 { "ibm,errinjct", -1, 2, -1, -1, -1, 1024 },
1028 { "ibm,close-errinjct", -1, -1, -1, -1, -1 },
1029 { "ibm,open-errinjct", -1, -1, -1, -1, -1 },
1030 { "ibm,get-config-addr-info2", -1, -1, -1, -1, -1 },
1031 { "ibm,get-dynamic-sensor-state", -1, 1, -1, -1, -1 },
1032 { "ibm,get-indices", -1, 2, 3, -1, -1 },
1033 { "get-power-level", -1, -1, -1, -1, -1 },
1034 { "get-sensor-state", -1, -1, -1, -1, -1 },
1035 { "ibm,get-system-parameter", -1, 1, 2, -1, -1 },
1036 { "get-time-of-day", -1, -1, -1, -1, -1 },
1037 { "ibm,get-vpd", -1, 0, -1, 1, 2 },
1038 { "ibm,lpar-perftools", -1, 2, 3, -1, -1 },
1039 { "ibm,platform-dump", -1, 4, 5, -1, -1 }, /* Special cased */
1040 { "ibm,read-slot-reset-state", -1, -1, -1, -1, -1 },
1041 { "ibm,scan-log-dump", -1, 0, 1, -1, -1 },
1042 { "ibm,set-dynamic-indicator", -1, 2, -1, -1, -1 },
1043 { "ibm,set-eeh-option", -1, -1, -1, -1, -1 },
1044 { "set-indicator", -1, -1, -1, -1, -1 },
1045 { "set-power-level", -1, -1, -1, -1, -1 },
1046 { "set-time-for-power-on", -1, -1, -1, -1, -1 },
1047 { "ibm,set-system-parameter", -1, 1, -1, -1, -1 },
1048 { "set-time-of-day", -1, -1, -1, -1, -1 },
1049 #ifdef CONFIG_CPU_BIG_ENDIAN
1050 { "ibm,suspend-me", -1, -1, -1, -1, -1 },
1051 { "ibm,update-nodes", -1, 0, -1, -1, -1, 4096 },
1052 { "ibm,update-properties", -1, 0, -1, -1, -1, 4096 },
1053 #endif
1054 { "ibm,physical-attestation", -1, 0, 1, -1, -1 },
1055 };
1056
in_rmo_buf(u32 base,u32 end)1057 static bool in_rmo_buf(u32 base, u32 end)
1058 {
1059 return base >= rtas_rmo_buf &&
1060 base < (rtas_rmo_buf + RTAS_USER_REGION_SIZE) &&
1061 base <= end &&
1062 end >= rtas_rmo_buf &&
1063 end < (rtas_rmo_buf + RTAS_USER_REGION_SIZE);
1064 }
1065
block_rtas_call(int token,int nargs,struct rtas_args * args)1066 static bool block_rtas_call(int token, int nargs,
1067 struct rtas_args *args)
1068 {
1069 int i;
1070
1071 for (i = 0; i < ARRAY_SIZE(rtas_filters); i++) {
1072 struct rtas_filter *f = &rtas_filters[i];
1073 u32 base, size, end;
1074
1075 if (token != f->token)
1076 continue;
1077
1078 if (f->buf_idx1 != -1) {
1079 base = be32_to_cpu(args->args[f->buf_idx1]);
1080 if (f->size_idx1 != -1)
1081 size = be32_to_cpu(args->args[f->size_idx1]);
1082 else if (f->fixed_size)
1083 size = f->fixed_size;
1084 else
1085 size = 1;
1086
1087 end = base + size - 1;
1088
1089 /*
1090 * Special case for ibm,platform-dump - NULL buffer
1091 * address is used to indicate end of dump processing
1092 */
1093 if (!strcmp(f->name, "ibm,platform-dump") &&
1094 base == 0)
1095 return false;
1096
1097 if (!in_rmo_buf(base, end))
1098 goto err;
1099 }
1100
1101 if (f->buf_idx2 != -1) {
1102 base = be32_to_cpu(args->args[f->buf_idx2]);
1103 if (f->size_idx2 != -1)
1104 size = be32_to_cpu(args->args[f->size_idx2]);
1105 else if (f->fixed_size)
1106 size = f->fixed_size;
1107 else
1108 size = 1;
1109 end = base + size - 1;
1110
1111 /*
1112 * Special case for ibm,configure-connector where the
1113 * address can be 0
1114 */
1115 if (!strcmp(f->name, "ibm,configure-connector") &&
1116 base == 0)
1117 return false;
1118
1119 if (!in_rmo_buf(base, end))
1120 goto err;
1121 }
1122
1123 return false;
1124 }
1125
1126 err:
1127 pr_err_ratelimited("sys_rtas: RTAS call blocked - exploit attempt?\n");
1128 pr_err_ratelimited("sys_rtas: token=0x%x, nargs=%d (called by %s)\n",
1129 token, nargs, current->comm);
1130 return true;
1131 }
1132
rtas_syscall_filter_init(void)1133 static void __init rtas_syscall_filter_init(void)
1134 {
1135 unsigned int i;
1136
1137 for (i = 0; i < ARRAY_SIZE(rtas_filters); i++)
1138 rtas_filters[i].token = rtas_token(rtas_filters[i].name);
1139 }
1140
1141 #else
1142
block_rtas_call(int token,int nargs,struct rtas_args * args)1143 static bool block_rtas_call(int token, int nargs,
1144 struct rtas_args *args)
1145 {
1146 return false;
1147 }
1148
rtas_syscall_filter_init(void)1149 static void __init rtas_syscall_filter_init(void)
1150 {
1151 }
1152
1153 #endif /* CONFIG_PPC_RTAS_FILTER */
1154
1155 /* We assume to be passed big endian arguments */
SYSCALL_DEFINE1(rtas,struct rtas_args __user *,uargs)1156 SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs)
1157 {
1158 struct rtas_args args;
1159 unsigned long flags;
1160 char *buff_copy, *errbuf = NULL;
1161 int nargs, nret, token;
1162
1163 if (!capable(CAP_SYS_ADMIN))
1164 return -EPERM;
1165
1166 if (!rtas.entry)
1167 return -EINVAL;
1168
1169 if (copy_from_user(&args, uargs, 3 * sizeof(u32)) != 0)
1170 return -EFAULT;
1171
1172 nargs = be32_to_cpu(args.nargs);
1173 nret = be32_to_cpu(args.nret);
1174 token = be32_to_cpu(args.token);
1175
1176 if (nargs >= ARRAY_SIZE(args.args)
1177 || nret > ARRAY_SIZE(args.args)
1178 || nargs + nret > ARRAY_SIZE(args.args))
1179 return -EINVAL;
1180
1181 /* Copy in args. */
1182 if (copy_from_user(args.args, uargs->args,
1183 nargs * sizeof(rtas_arg_t)) != 0)
1184 return -EFAULT;
1185
1186 if (token == RTAS_UNKNOWN_SERVICE)
1187 return -EINVAL;
1188
1189 args.rets = &args.args[nargs];
1190 memset(args.rets, 0, nret * sizeof(rtas_arg_t));
1191
1192 if (block_rtas_call(token, nargs, &args))
1193 return -EINVAL;
1194
1195 if (token == ibm_open_errinjct_token || token == ibm_errinjct_token) {
1196 int err;
1197
1198 err = security_locked_down(LOCKDOWN_RTAS_ERROR_INJECTION);
1199 if (err)
1200 return err;
1201 }
1202
1203 /* Need to handle ibm,suspend_me call specially */
1204 if (token == rtas_token("ibm,suspend-me")) {
1205
1206 /*
1207 * rtas_ibm_suspend_me assumes the streamid handle is in cpu
1208 * endian, or at least the hcall within it requires it.
1209 */
1210 int rc = 0;
1211 u64 handle = ((u64)be32_to_cpu(args.args[0]) << 32)
1212 | be32_to_cpu(args.args[1]);
1213 rc = rtas_syscall_dispatch_ibm_suspend_me(handle);
1214 if (rc == -EAGAIN)
1215 args.rets[0] = cpu_to_be32(RTAS_NOT_SUSPENDABLE);
1216 else if (rc == -EIO)
1217 args.rets[0] = cpu_to_be32(-1);
1218 else if (rc)
1219 return rc;
1220 goto copy_return;
1221 }
1222
1223 buff_copy = get_errorlog_buffer();
1224
1225 flags = lock_rtas();
1226
1227 rtas.args = args;
1228 do_enter_rtas(__pa(&rtas.args));
1229 args = rtas.args;
1230
1231 /* A -1 return code indicates that the last command couldn't
1232 be completed due to a hardware error. */
1233 if (be32_to_cpu(args.rets[0]) == -1)
1234 errbuf = __fetch_rtas_last_error(buff_copy);
1235
1236 unlock_rtas(flags);
1237
1238 if (buff_copy) {
1239 if (errbuf)
1240 log_error(errbuf, ERR_TYPE_RTAS_LOG, 0);
1241 kfree(buff_copy);
1242 }
1243
1244 copy_return:
1245 /* Copy out args. */
1246 if (copy_to_user(uargs->args + nargs,
1247 args.args + nargs,
1248 nret * sizeof(rtas_arg_t)) != 0)
1249 return -EFAULT;
1250
1251 return 0;
1252 }
1253
1254 /*
1255 * Call early during boot, before mem init, to retrieve the RTAS
1256 * information from the device-tree and allocate the RMO buffer for userland
1257 * accesses.
1258 */
rtas_initialize(void)1259 void __init rtas_initialize(void)
1260 {
1261 unsigned long rtas_region = RTAS_INSTANTIATE_MAX;
1262 u32 base, size, entry;
1263 int no_base, no_size, no_entry;
1264
1265 /* Get RTAS dev node and fill up our "rtas" structure with infos
1266 * about it.
1267 */
1268 rtas.dev = of_find_node_by_name(NULL, "rtas");
1269 if (!rtas.dev)
1270 return;
1271
1272 no_base = of_property_read_u32(rtas.dev, "linux,rtas-base", &base);
1273 no_size = of_property_read_u32(rtas.dev, "rtas-size", &size);
1274 if (no_base || no_size) {
1275 of_node_put(rtas.dev);
1276 rtas.dev = NULL;
1277 return;
1278 }
1279
1280 rtas.base = base;
1281 rtas.size = size;
1282 no_entry = of_property_read_u32(rtas.dev, "linux,rtas-entry", &entry);
1283 rtas.entry = no_entry ? rtas.base : entry;
1284
1285 /*
1286 * Discover these now to avoid device tree lookups in the
1287 * panic path.
1288 */
1289 if (of_property_read_bool(rtas.dev, "ibm,extended-os-term"))
1290 ibm_os_term_token = rtas_token("ibm,os-term");
1291
1292 /* If RTAS was found, allocate the RMO buffer for it and look for
1293 * the stop-self token if any
1294 */
1295 #ifdef CONFIG_PPC64
1296 if (firmware_has_feature(FW_FEATURE_LPAR))
1297 rtas_region = min(ppc64_rma_size, RTAS_INSTANTIATE_MAX);
1298 #endif
1299 rtas_rmo_buf = memblock_phys_alloc_range(RTAS_USER_REGION_SIZE, PAGE_SIZE,
1300 0, rtas_region);
1301 if (!rtas_rmo_buf)
1302 panic("ERROR: RTAS: Failed to allocate %lx bytes below %pa\n",
1303 PAGE_SIZE, &rtas_region);
1304
1305 #ifdef CONFIG_RTAS_ERROR_LOGGING
1306 rtas_last_error_token = rtas_token("rtas-last-error");
1307 #endif
1308 ibm_open_errinjct_token = rtas_token("ibm,open-errinjct");
1309 ibm_errinjct_token = rtas_token("ibm,errinjct");
1310 rtas_syscall_filter_init();
1311 }
1312
early_init_dt_scan_rtas(unsigned long node,const char * uname,int depth,void * data)1313 int __init early_init_dt_scan_rtas(unsigned long node,
1314 const char *uname, int depth, void *data)
1315 {
1316 const u32 *basep, *entryp, *sizep;
1317
1318 if (depth != 1 || strcmp(uname, "rtas") != 0)
1319 return 0;
1320
1321 basep = of_get_flat_dt_prop(node, "linux,rtas-base", NULL);
1322 entryp = of_get_flat_dt_prop(node, "linux,rtas-entry", NULL);
1323 sizep = of_get_flat_dt_prop(node, "rtas-size", NULL);
1324
1325 #ifdef CONFIG_PPC64
1326 /* need this feature to decide the crashkernel offset */
1327 if (of_get_flat_dt_prop(node, "ibm,hypertas-functions", NULL))
1328 powerpc_firmware_features |= FW_FEATURE_LPAR;
1329 #endif
1330
1331 if (basep && entryp && sizep) {
1332 rtas.base = *basep;
1333 rtas.entry = *entryp;
1334 rtas.size = *sizep;
1335 }
1336
1337 #ifdef CONFIG_UDBG_RTAS_CONSOLE
1338 basep = of_get_flat_dt_prop(node, "put-term-char", NULL);
1339 if (basep)
1340 rtas_putchar_token = *basep;
1341
1342 basep = of_get_flat_dt_prop(node, "get-term-char", NULL);
1343 if (basep)
1344 rtas_getchar_token = *basep;
1345
1346 if (rtas_putchar_token != RTAS_UNKNOWN_SERVICE &&
1347 rtas_getchar_token != RTAS_UNKNOWN_SERVICE)
1348 udbg_init_rtas_console();
1349
1350 #endif
1351
1352 /* break now */
1353 return 1;
1354 }
1355
1356 static arch_spinlock_t timebase_lock;
1357 static u64 timebase = 0;
1358
rtas_give_timebase(void)1359 void rtas_give_timebase(void)
1360 {
1361 unsigned long flags;
1362
1363 local_irq_save(flags);
1364 hard_irq_disable();
1365 arch_spin_lock(&timebase_lock);
1366 rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL);
1367 timebase = get_tb();
1368 arch_spin_unlock(&timebase_lock);
1369
1370 while (timebase)
1371 barrier();
1372 rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL);
1373 local_irq_restore(flags);
1374 }
1375
rtas_take_timebase(void)1376 void rtas_take_timebase(void)
1377 {
1378 while (!timebase)
1379 barrier();
1380 arch_spin_lock(&timebase_lock);
1381 set_tb(timebase >> 32, timebase & 0xffffffff);
1382 timebase = 0;
1383 arch_spin_unlock(&timebase_lock);
1384 }
1385