1 /*
2  * Copyright (C) 2001 Dave Engebretsen IBM Corporation
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
17  */
18 
19 #include <linux/sched.h>
20 #include <linux/interrupt.h>
21 #include <linux/irq.h>
22 #include <linux/of.h>
23 #include <linux/fs.h>
24 #include <linux/reboot.h>
25 
26 #include <asm/machdep.h>
27 #include <asm/rtas.h>
28 #include <asm/firmware.h>
29 
30 #include "pseries.h"
31 
32 static unsigned char ras_log_buf[RTAS_ERROR_LOG_MAX];
33 static DEFINE_SPINLOCK(ras_log_buf_lock);
34 
35 static char global_mce_data_buf[RTAS_ERROR_LOG_MAX];
36 static DEFINE_PER_CPU(__u64, mce_data_buf);
37 
38 static int ras_check_exception_token;
39 
40 #define EPOW_SENSOR_TOKEN	9
41 #define EPOW_SENSOR_INDEX	0
42 
43 /* EPOW events counter variable */
44 static int num_epow_events;
45 
46 static irqreturn_t ras_hotplug_interrupt(int irq, void *dev_id);
47 static irqreturn_t ras_epow_interrupt(int irq, void *dev_id);
48 static irqreturn_t ras_error_interrupt(int irq, void *dev_id);
49 
50 
51 /*
52  * Initialize handlers for the set of interrupts caused by hardware errors
53  * and power system events.
54  */
55 static int __init init_ras_IRQ(void)
56 {
57 	struct device_node *np;
58 
59 	ras_check_exception_token = rtas_token("check-exception");
60 
61 	/* Internal Errors */
62 	np = of_find_node_by_path("/event-sources/internal-errors");
63 	if (np != NULL) {
64 		request_event_sources_irqs(np, ras_error_interrupt,
65 					   "RAS_ERROR");
66 		of_node_put(np);
67 	}
68 
69 	/* Hotplug Events */
70 	np = of_find_node_by_path("/event-sources/hot-plug-events");
71 	if (np != NULL) {
72 		request_event_sources_irqs(np, ras_hotplug_interrupt,
73 					   "RAS_HOTPLUG");
74 		of_node_put(np);
75 	}
76 
77 	/* EPOW Events */
78 	np = of_find_node_by_path("/event-sources/epow-events");
79 	if (np != NULL) {
80 		request_event_sources_irqs(np, ras_epow_interrupt, "RAS_EPOW");
81 		of_node_put(np);
82 	}
83 
84 	return 0;
85 }
86 machine_subsys_initcall(pseries, init_ras_IRQ);
87 
88 #define EPOW_SHUTDOWN_NORMAL				1
89 #define EPOW_SHUTDOWN_ON_UPS				2
90 #define EPOW_SHUTDOWN_LOSS_OF_CRITICAL_FUNCTIONS	3
91 #define EPOW_SHUTDOWN_AMBIENT_TEMPERATURE_TOO_HIGH	4
92 
93 static void handle_system_shutdown(char event_modifier)
94 {
95 	switch (event_modifier) {
96 	case EPOW_SHUTDOWN_NORMAL:
97 		pr_emerg("Power off requested\n");
98 		orderly_poweroff(true);
99 		break;
100 
101 	case EPOW_SHUTDOWN_ON_UPS:
102 		pr_emerg("Loss of system power detected. System is running on"
103 			 " UPS/battery. Check RTAS error log for details\n");
104 		orderly_poweroff(true);
105 		break;
106 
107 	case EPOW_SHUTDOWN_LOSS_OF_CRITICAL_FUNCTIONS:
108 		pr_emerg("Loss of system critical functions detected. Check"
109 			 " RTAS error log for details\n");
110 		orderly_poweroff(true);
111 		break;
112 
113 	case EPOW_SHUTDOWN_AMBIENT_TEMPERATURE_TOO_HIGH:
114 		pr_emerg("High ambient temperature detected. Check RTAS"
115 			 " error log for details\n");
116 		orderly_poweroff(true);
117 		break;
118 
119 	default:
120 		pr_err("Unknown power/cooling shutdown event (modifier = %d)\n",
121 			event_modifier);
122 	}
123 }
124 
125 struct epow_errorlog {
126 	unsigned char sensor_value;
127 	unsigned char event_modifier;
128 	unsigned char extended_modifier;
129 	unsigned char reserved;
130 	unsigned char platform_reason;
131 };
132 
133 #define EPOW_RESET			0
134 #define EPOW_WARN_COOLING		1
135 #define EPOW_WARN_POWER			2
136 #define EPOW_SYSTEM_SHUTDOWN		3
137 #define EPOW_SYSTEM_HALT		4
138 #define EPOW_MAIN_ENCLOSURE		5
139 #define EPOW_POWER_OFF			7
140 
141 static void rtas_parse_epow_errlog(struct rtas_error_log *log)
142 {
143 	struct pseries_errorlog *pseries_log;
144 	struct epow_errorlog *epow_log;
145 	char action_code;
146 	char modifier;
147 
148 	pseries_log = get_pseries_errorlog(log, PSERIES_ELOG_SECT_ID_EPOW);
149 	if (pseries_log == NULL)
150 		return;
151 
152 	epow_log = (struct epow_errorlog *)pseries_log->data;
153 	action_code = epow_log->sensor_value & 0xF;	/* bottom 4 bits */
154 	modifier = epow_log->event_modifier & 0xF;	/* bottom 4 bits */
155 
156 	switch (action_code) {
157 	case EPOW_RESET:
158 		if (num_epow_events) {
159 			pr_info("Non critical power/cooling issue cleared\n");
160 			num_epow_events--;
161 		}
162 		break;
163 
164 	case EPOW_WARN_COOLING:
165 		pr_info("Non-critical cooling issue detected. Check RTAS error"
166 			" log for details\n");
167 		break;
168 
169 	case EPOW_WARN_POWER:
170 		pr_info("Non-critical power issue detected. Check RTAS error"
171 			" log for details\n");
172 		break;
173 
174 	case EPOW_SYSTEM_SHUTDOWN:
175 		handle_system_shutdown(epow_log->event_modifier);
176 		break;
177 
178 	case EPOW_SYSTEM_HALT:
179 		pr_emerg("Critical power/cooling issue detected. Check RTAS"
180 			 " error log for details. Powering off.\n");
181 		orderly_poweroff(true);
182 		break;
183 
184 	case EPOW_MAIN_ENCLOSURE:
185 	case EPOW_POWER_OFF:
186 		pr_emerg("System about to lose power. Check RTAS error log "
187 			 " for details. Powering off immediately.\n");
188 		emergency_sync();
189 		kernel_power_off();
190 		break;
191 
192 	default:
193 		pr_err("Unknown power/cooling event (action code  = %d)\n",
194 			action_code);
195 	}
196 
197 	/* Increment epow events counter variable */
198 	if (action_code != EPOW_RESET)
199 		num_epow_events++;
200 }
201 
202 static irqreturn_t ras_hotplug_interrupt(int irq, void *dev_id)
203 {
204 	struct pseries_errorlog *pseries_log;
205 	struct pseries_hp_errorlog *hp_elog;
206 
207 	spin_lock(&ras_log_buf_lock);
208 
209 	rtas_call(ras_check_exception_token, 6, 1, NULL,
210 		  RTAS_VECTOR_EXTERNAL_INTERRUPT, virq_to_hw(irq),
211 		  RTAS_HOTPLUG_EVENTS, 0, __pa(&ras_log_buf),
212 		  rtas_get_error_log_max());
213 
214 	pseries_log = get_pseries_errorlog((struct rtas_error_log *)ras_log_buf,
215 					   PSERIES_ELOG_SECT_ID_HOTPLUG);
216 	hp_elog = (struct pseries_hp_errorlog *)pseries_log->data;
217 
218 	/*
219 	 * Since PCI hotplug is not currently supported on pseries, put PCI
220 	 * hotplug events on the ras_log_buf to be handled by rtas_errd.
221 	 */
222 	if (hp_elog->resource == PSERIES_HP_ELOG_RESOURCE_MEM ||
223 	    hp_elog->resource == PSERIES_HP_ELOG_RESOURCE_CPU)
224 		queue_hotplug_event(hp_elog, NULL, NULL);
225 	else
226 		log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, 0);
227 
228 	spin_unlock(&ras_log_buf_lock);
229 	return IRQ_HANDLED;
230 }
231 
232 /* Handle environmental and power warning (EPOW) interrupts. */
233 static irqreturn_t ras_epow_interrupt(int irq, void *dev_id)
234 {
235 	int status;
236 	int state;
237 	int critical;
238 
239 	status = rtas_get_sensor_fast(EPOW_SENSOR_TOKEN, EPOW_SENSOR_INDEX,
240 				      &state);
241 
242 	if (state > 3)
243 		critical = 1;		/* Time Critical */
244 	else
245 		critical = 0;
246 
247 	spin_lock(&ras_log_buf_lock);
248 
249 	status = rtas_call(ras_check_exception_token, 6, 1, NULL,
250 			   RTAS_VECTOR_EXTERNAL_INTERRUPT,
251 			   virq_to_hw(irq),
252 			   RTAS_EPOW_WARNING,
253 			   critical, __pa(&ras_log_buf),
254 				rtas_get_error_log_max());
255 
256 	log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, 0);
257 
258 	rtas_parse_epow_errlog((struct rtas_error_log *)ras_log_buf);
259 
260 	spin_unlock(&ras_log_buf_lock);
261 	return IRQ_HANDLED;
262 }
263 
264 /*
265  * Handle hardware error interrupts.
266  *
267  * RTAS check-exception is called to collect data on the exception.  If
268  * the error is deemed recoverable, we log a warning and return.
269  * For nonrecoverable errors, an error is logged and we stop all processing
270  * as quickly as possible in order to prevent propagation of the failure.
271  */
272 static irqreturn_t ras_error_interrupt(int irq, void *dev_id)
273 {
274 	struct rtas_error_log *rtas_elog;
275 	int status;
276 	int fatal;
277 
278 	spin_lock(&ras_log_buf_lock);
279 
280 	status = rtas_call(ras_check_exception_token, 6, 1, NULL,
281 			   RTAS_VECTOR_EXTERNAL_INTERRUPT,
282 			   virq_to_hw(irq),
283 			   RTAS_INTERNAL_ERROR, 1 /* Time Critical */,
284 			   __pa(&ras_log_buf),
285 				rtas_get_error_log_max());
286 
287 	rtas_elog = (struct rtas_error_log *)ras_log_buf;
288 
289 	if (status == 0 &&
290 	    rtas_error_severity(rtas_elog) >= RTAS_SEVERITY_ERROR_SYNC)
291 		fatal = 1;
292 	else
293 		fatal = 0;
294 
295 	/* format and print the extended information */
296 	log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, fatal);
297 
298 	if (fatal) {
299 		pr_emerg("Fatal hardware error detected. Check RTAS error"
300 			 " log for details. Powering off immediately\n");
301 		emergency_sync();
302 		kernel_power_off();
303 	} else {
304 		pr_err("Recoverable hardware error detected\n");
305 	}
306 
307 	spin_unlock(&ras_log_buf_lock);
308 	return IRQ_HANDLED;
309 }
310 
311 /*
312  * Some versions of FWNMI place the buffer inside the 4kB page starting at
313  * 0x7000. Other versions place it inside the rtas buffer. We check both.
314  */
315 #define VALID_FWNMI_BUFFER(A) \
316 	((((A) >= 0x7000) && ((A) < 0x7ff0)) || \
317 	(((A) >= rtas.base) && ((A) < (rtas.base + rtas.size - 16))))
318 
319 /*
320  * Get the error information for errors coming through the
321  * FWNMI vectors.  The pt_regs' r3 will be updated to reflect
322  * the actual r3 if possible, and a ptr to the error log entry
323  * will be returned if found.
324  *
325  * If the RTAS error is not of the extended type, then we put it in a per
326  * cpu 64bit buffer. If it is the extended type we use global_mce_data_buf.
327  *
328  * The global_mce_data_buf does not have any locks or protection around it,
329  * if a second machine check comes in, or a system reset is done
330  * before we have logged the error, then we will get corruption in the
331  * error log.  This is preferable over holding off on calling
332  * ibm,nmi-interlock which would result in us checkstopping if a
333  * second machine check did come in.
334  */
335 static struct rtas_error_log *fwnmi_get_errinfo(struct pt_regs *regs)
336 {
337 	unsigned long *savep;
338 	struct rtas_error_log *h, *errhdr = NULL;
339 
340 	/* Mask top two bits */
341 	regs->gpr[3] &= ~(0x3UL << 62);
342 
343 	if (!VALID_FWNMI_BUFFER(regs->gpr[3])) {
344 		printk(KERN_ERR "FWNMI: corrupt r3 0x%016lx\n", regs->gpr[3]);
345 		return NULL;
346 	}
347 
348 	savep = __va(regs->gpr[3]);
349 	regs->gpr[3] = savep[0];	/* restore original r3 */
350 
351 	/* If it isn't an extended log we can use the per cpu 64bit buffer */
352 	h = (struct rtas_error_log *)&savep[1];
353 	if (!rtas_error_extended(h)) {
354 		memcpy(this_cpu_ptr(&mce_data_buf), h, sizeof(__u64));
355 		errhdr = (struct rtas_error_log *)this_cpu_ptr(&mce_data_buf);
356 	} else {
357 		int len, error_log_length;
358 
359 		error_log_length = 8 + rtas_error_extended_log_length(h);
360 		len = max_t(int, error_log_length, RTAS_ERROR_LOG_MAX);
361 		memset(global_mce_data_buf, 0, RTAS_ERROR_LOG_MAX);
362 		memcpy(global_mce_data_buf, h, len);
363 		errhdr = (struct rtas_error_log *)global_mce_data_buf;
364 	}
365 
366 	return errhdr;
367 }
368 
369 /* Call this when done with the data returned by FWNMI_get_errinfo.
370  * It will release the saved data area for other CPUs in the
371  * partition to receive FWNMI errors.
372  */
373 static void fwnmi_release_errinfo(void)
374 {
375 	int ret = rtas_call(rtas_token("ibm,nmi-interlock"), 0, 1, NULL);
376 	if (ret != 0)
377 		printk(KERN_ERR "FWNMI: nmi-interlock failed: %d\n", ret);
378 }
379 
380 int pSeries_system_reset_exception(struct pt_regs *regs)
381 {
382 	if (fwnmi_active) {
383 		struct rtas_error_log *errhdr = fwnmi_get_errinfo(regs);
384 		if (errhdr) {
385 			/* XXX Should look at FWNMI information */
386 		}
387 		fwnmi_release_errinfo();
388 	}
389 	return 0; /* need to perform reset */
390 }
391 
392 /*
393  * See if we can recover from a machine check exception.
394  * This is only called on power4 (or above) and only via
395  * the Firmware Non-Maskable Interrupts (fwnmi) handler
396  * which provides the error analysis for us.
397  *
398  * Return 1 if corrected (or delivered a signal).
399  * Return 0 if there is nothing we can do.
400  */
401 static int recover_mce(struct pt_regs *regs, struct rtas_error_log *err)
402 {
403 	int recovered = 0;
404 	int disposition = rtas_error_disposition(err);
405 
406 	if (!(regs->msr & MSR_RI)) {
407 		/* If MSR_RI isn't set, we cannot recover */
408 		recovered = 0;
409 
410 	} else if (disposition == RTAS_DISP_FULLY_RECOVERED) {
411 		/* Platform corrected itself */
412 		recovered = 1;
413 
414 	} else if (disposition == RTAS_DISP_LIMITED_RECOVERY) {
415 		/* Platform corrected itself but could be degraded */
416 		printk(KERN_ERR "MCE: limited recovery, system may "
417 		       "be degraded\n");
418 		recovered = 1;
419 
420 	} else if (user_mode(regs) && !is_global_init(current) &&
421 		   rtas_error_severity(err) == RTAS_SEVERITY_ERROR_SYNC) {
422 
423 		/*
424 		 * If we received a synchronous error when in userspace
425 		 * kill the task. Firmware may report details of the fail
426 		 * asynchronously, so we can't rely on the target and type
427 		 * fields being valid here.
428 		 */
429 		printk(KERN_ERR "MCE: uncorrectable error, killing task "
430 		       "%s:%d\n", current->comm, current->pid);
431 
432 		_exception(SIGBUS, regs, BUS_MCEERR_AR, regs->nip);
433 		recovered = 1;
434 	}
435 
436 	log_error((char *)err, ERR_TYPE_RTAS_LOG, 0);
437 
438 	return recovered;
439 }
440 
441 /*
442  * Handle a machine check.
443  *
444  * Note that on Power 4 and beyond Firmware Non-Maskable Interrupts (fwnmi)
445  * should be present.  If so the handler which called us tells us if the
446  * error was recovered (never true if RI=0).
447  *
448  * On hardware prior to Power 4 these exceptions were asynchronous which
449  * means we can't tell exactly where it occurred and so we can't recover.
450  */
451 int pSeries_machine_check_exception(struct pt_regs *regs)
452 {
453 	struct rtas_error_log *errp;
454 
455 	if (fwnmi_active) {
456 		errp = fwnmi_get_errinfo(regs);
457 		fwnmi_release_errinfo();
458 		if (errp && recover_mce(regs, errp))
459 			return 1;
460 	}
461 
462 	return 0;
463 }
464