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/arch/powerpc/platforms/pseries/ras.c

https://github.com/othane/linux
C | 424 lines | 262 code | 72 blank | 90 comment | 40 complexity | e146736169de98218f0b919d7a0424f9 MD5 | raw file
  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
 32static unsigned char ras_log_buf[RTAS_ERROR_LOG_MAX];
 33static DEFINE_SPINLOCK(ras_log_buf_lock);
 34
 35static char global_mce_data_buf[RTAS_ERROR_LOG_MAX];
 36static DEFINE_PER_CPU(__u64, mce_data_buf);
 37
 38static int ras_check_exception_token;
 39
 40#define EPOW_SENSOR_TOKEN	9
 41#define EPOW_SENSOR_INDEX	0
 42
 43/* EPOW events counter variable */
 44static int num_epow_events;
 45
 46static irqreturn_t ras_epow_interrupt(int irq, void *dev_id);
 47static irqreturn_t ras_error_interrupt(int irq, void *dev_id);
 48
 49
 50/*
 51 * Initialize handlers for the set of interrupts caused by hardware errors
 52 * and power system events.
 53 */
 54static int __init init_ras_IRQ(void)
 55{
 56	struct device_node *np;
 57
 58	ras_check_exception_token = rtas_token("check-exception");
 59
 60	/* Internal Errors */
 61	np = of_find_node_by_path("/event-sources/internal-errors");
 62	if (np != NULL) {
 63		request_event_sources_irqs(np, ras_error_interrupt,
 64					   "RAS_ERROR");
 65		of_node_put(np);
 66	}
 67
 68	/* EPOW Events */
 69	np = of_find_node_by_path("/event-sources/epow-events");
 70	if (np != NULL) {
 71		request_event_sources_irqs(np, ras_epow_interrupt, "RAS_EPOW");
 72		of_node_put(np);
 73	}
 74
 75	return 0;
 76}
 77machine_subsys_initcall(pseries, init_ras_IRQ);
 78
 79#define EPOW_SHUTDOWN_NORMAL				1
 80#define EPOW_SHUTDOWN_ON_UPS				2
 81#define EPOW_SHUTDOWN_LOSS_OF_CRITICAL_FUNCTIONS	3
 82#define EPOW_SHUTDOWN_AMBIENT_TEMPERATURE_TOO_HIGH	4
 83
 84static void handle_system_shutdown(char event_modifier)
 85{
 86	switch (event_modifier) {
 87	case EPOW_SHUTDOWN_NORMAL:
 88		pr_emerg("Power off requested\n");
 89		orderly_poweroff(true);
 90		break;
 91
 92	case EPOW_SHUTDOWN_ON_UPS:
 93		pr_emerg("Loss of system power detected. System is running on"
 94			 " UPS/battery. Check RTAS error log for details\n");
 95		orderly_poweroff(true);
 96		break;
 97
 98	case EPOW_SHUTDOWN_LOSS_OF_CRITICAL_FUNCTIONS:
 99		pr_emerg("Loss of system critical functions detected. Check"
100			 " RTAS error log for details\n");
101		orderly_poweroff(true);
102		break;
103
104	case EPOW_SHUTDOWN_AMBIENT_TEMPERATURE_TOO_HIGH:
105		pr_emerg("High ambient temperature detected. Check RTAS"
106			 " error log for details\n");
107		orderly_poweroff(true);
108		break;
109
110	default:
111		pr_err("Unknown power/cooling shutdown event (modifier = %d)\n",
112			event_modifier);
113	}
114}
115
116struct epow_errorlog {
117	unsigned char sensor_value;
118	unsigned char event_modifier;
119	unsigned char extended_modifier;
120	unsigned char reserved;
121	unsigned char platform_reason;
122};
123
124#define EPOW_RESET			0
125#define EPOW_WARN_COOLING		1
126#define EPOW_WARN_POWER			2
127#define EPOW_SYSTEM_SHUTDOWN		3
128#define EPOW_SYSTEM_HALT		4
129#define EPOW_MAIN_ENCLOSURE		5
130#define EPOW_POWER_OFF			7
131
132static void rtas_parse_epow_errlog(struct rtas_error_log *log)
133{
134	struct pseries_errorlog *pseries_log;
135	struct epow_errorlog *epow_log;
136	char action_code;
137	char modifier;
138
139	pseries_log = get_pseries_errorlog(log, PSERIES_ELOG_SECT_ID_EPOW);
140	if (pseries_log == NULL)
141		return;
142
143	epow_log = (struct epow_errorlog *)pseries_log->data;
144	action_code = epow_log->sensor_value & 0xF;	/* bottom 4 bits */
145	modifier = epow_log->event_modifier & 0xF;	/* bottom 4 bits */
146
147	switch (action_code) {
148	case EPOW_RESET:
149		if (num_epow_events) {
150			pr_info("Non critical power/cooling issue cleared\n");
151			num_epow_events--;
152		}
153		break;
154
155	case EPOW_WARN_COOLING:
156		pr_info("Non-critical cooling issue detected. Check RTAS error"
157			" log for details\n");
158		break;
159
160	case EPOW_WARN_POWER:
161		pr_info("Non-critical power issue detected. Check RTAS error"
162			" log for details\n");
163		break;
164
165	case EPOW_SYSTEM_SHUTDOWN:
166		handle_system_shutdown(epow_log->event_modifier);
167		break;
168
169	case EPOW_SYSTEM_HALT:
170		pr_emerg("Critical power/cooling issue detected. Check RTAS"
171			 " error log for details. Powering off.\n");
172		orderly_poweroff(true);
173		break;
174
175	case EPOW_MAIN_ENCLOSURE:
176	case EPOW_POWER_OFF:
177		pr_emerg("System about to lose power. Check RTAS error log "
178			 " for details. Powering off immediately.\n");
179		emergency_sync();
180		kernel_power_off();
181		break;
182
183	default:
184		pr_err("Unknown power/cooling event (action code  = %d)\n",
185			action_code);
186	}
187
188	/* Increment epow events counter variable */
189	if (action_code != EPOW_RESET)
190		num_epow_events++;
191}
192
193/* Handle environmental and power warning (EPOW) interrupts. */
194static irqreturn_t ras_epow_interrupt(int irq, void *dev_id)
195{
196	int status;
197	int state;
198	int critical;
199
200	status = rtas_get_sensor_fast(EPOW_SENSOR_TOKEN, EPOW_SENSOR_INDEX,
201				      &state);
202
203	if (state > 3)
204		critical = 1;		/* Time Critical */
205	else
206		critical = 0;
207
208	spin_lock(&ras_log_buf_lock);
209
210	status = rtas_call(ras_check_exception_token, 6, 1, NULL,
211			   RTAS_VECTOR_EXTERNAL_INTERRUPT,
212			   virq_to_hw(irq),
213			   RTAS_EPOW_WARNING,
214			   critical, __pa(&ras_log_buf),
215				rtas_get_error_log_max());
216
217	log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, 0);
218
219	rtas_parse_epow_errlog((struct rtas_error_log *)ras_log_buf);
220
221	spin_unlock(&ras_log_buf_lock);
222	return IRQ_HANDLED;
223}
224
225/*
226 * Handle hardware error interrupts.
227 *
228 * RTAS check-exception is called to collect data on the exception.  If
229 * the error is deemed recoverable, we log a warning and return.
230 * For nonrecoverable errors, an error is logged and we stop all processing
231 * as quickly as possible in order to prevent propagation of the failure.
232 */
233static irqreturn_t ras_error_interrupt(int irq, void *dev_id)
234{
235	struct rtas_error_log *rtas_elog;
236	int status;
237	int fatal;
238
239	spin_lock(&ras_log_buf_lock);
240
241	status = rtas_call(ras_check_exception_token, 6, 1, NULL,
242			   RTAS_VECTOR_EXTERNAL_INTERRUPT,
243			   virq_to_hw(irq),
244			   RTAS_INTERNAL_ERROR, 1 /* Time Critical */,
245			   __pa(&ras_log_buf),
246				rtas_get_error_log_max());
247
248	rtas_elog = (struct rtas_error_log *)ras_log_buf;
249
250	if (status == 0 &&
251	    rtas_error_severity(rtas_elog) >= RTAS_SEVERITY_ERROR_SYNC)
252		fatal = 1;
253	else
254		fatal = 0;
255
256	/* format and print the extended information */
257	log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, fatal);
258
259	if (fatal) {
260		pr_emerg("Fatal hardware error detected. Check RTAS error"
261			 " log for details. Powering off immediately\n");
262		emergency_sync();
263		kernel_power_off();
264	} else {
265		pr_err("Recoverable hardware error detected\n");
266	}
267
268	spin_unlock(&ras_log_buf_lock);
269	return IRQ_HANDLED;
270}
271
272/*
273 * Some versions of FWNMI place the buffer inside the 4kB page starting at
274 * 0x7000. Other versions place it inside the rtas buffer. We check both.
275 */
276#define VALID_FWNMI_BUFFER(A) \
277	((((A) >= 0x7000) && ((A) < 0x7ff0)) || \
278	(((A) >= rtas.base) && ((A) < (rtas.base + rtas.size - 16))))
279
280/*
281 * Get the error information for errors coming through the
282 * FWNMI vectors.  The pt_regs' r3 will be updated to reflect
283 * the actual r3 if possible, and a ptr to the error log entry
284 * will be returned if found.
285 *
286 * If the RTAS error is not of the extended type, then we put it in a per
287 * cpu 64bit buffer. If it is the extended type we use global_mce_data_buf.
288 *
289 * The global_mce_data_buf does not have any locks or protection around it,
290 * if a second machine check comes in, or a system reset is done
291 * before we have logged the error, then we will get corruption in the
292 * error log.  This is preferable over holding off on calling
293 * ibm,nmi-interlock which would result in us checkstopping if a
294 * second machine check did come in.
295 */
296static struct rtas_error_log *fwnmi_get_errinfo(struct pt_regs *regs)
297{
298	unsigned long *savep;
299	struct rtas_error_log *h, *errhdr = NULL;
300
301	/* Mask top two bits */
302	regs->gpr[3] &= ~(0x3UL << 62);
303
304	if (!VALID_FWNMI_BUFFER(regs->gpr[3])) {
305		printk(KERN_ERR "FWNMI: corrupt r3 0x%016lx\n", regs->gpr[3]);
306		return NULL;
307	}
308
309	savep = __va(regs->gpr[3]);
310	regs->gpr[3] = savep[0];	/* restore original r3 */
311
312	/* If it isn't an extended log we can use the per cpu 64bit buffer */
313	h = (struct rtas_error_log *)&savep[1];
314	if (!rtas_error_extended(h)) {
315		memcpy(this_cpu_ptr(&mce_data_buf), h, sizeof(__u64));
316		errhdr = (struct rtas_error_log *)this_cpu_ptr(&mce_data_buf);
317	} else {
318		int len, error_log_length;
319
320		error_log_length = 8 + rtas_error_extended_log_length(h);
321		len = max_t(int, error_log_length, RTAS_ERROR_LOG_MAX);
322		memset(global_mce_data_buf, 0, RTAS_ERROR_LOG_MAX);
323		memcpy(global_mce_data_buf, h, len);
324		errhdr = (struct rtas_error_log *)global_mce_data_buf;
325	}
326
327	return errhdr;
328}
329
330/* Call this when done with the data returned by FWNMI_get_errinfo.
331 * It will release the saved data area for other CPUs in the
332 * partition to receive FWNMI errors.
333 */
334static void fwnmi_release_errinfo(void)
335{
336	int ret = rtas_call(rtas_token("ibm,nmi-interlock"), 0, 1, NULL);
337	if (ret != 0)
338		printk(KERN_ERR "FWNMI: nmi-interlock failed: %d\n", ret);
339}
340
341int pSeries_system_reset_exception(struct pt_regs *regs)
342{
343	if (fwnmi_active) {
344		struct rtas_error_log *errhdr = fwnmi_get_errinfo(regs);
345		if (errhdr) {
346			/* XXX Should look at FWNMI information */
347		}
348		fwnmi_release_errinfo();
349	}
350	return 0; /* need to perform reset */
351}
352
353/*
354 * See if we can recover from a machine check exception.
355 * This is only called on power4 (or above) and only via
356 * the Firmware Non-Maskable Interrupts (fwnmi) handler
357 * which provides the error analysis for us.
358 *
359 * Return 1 if corrected (or delivered a signal).
360 * Return 0 if there is nothing we can do.
361 */
362static int recover_mce(struct pt_regs *regs, struct rtas_error_log *err)
363{
364	int recovered = 0;
365	int disposition = rtas_error_disposition(err);
366
367	if (!(regs->msr & MSR_RI)) {
368		/* If MSR_RI isn't set, we cannot recover */
369		recovered = 0;
370
371	} else if (disposition == RTAS_DISP_FULLY_RECOVERED) {
372		/* Platform corrected itself */
373		recovered = 1;
374
375	} else if (disposition == RTAS_DISP_LIMITED_RECOVERY) {
376		/* Platform corrected itself but could be degraded */
377		printk(KERN_ERR "MCE: limited recovery, system may "
378		       "be degraded\n");
379		recovered = 1;
380
381	} else if (user_mode(regs) && !is_global_init(current) &&
382		   rtas_error_severity(err) == RTAS_SEVERITY_ERROR_SYNC) {
383
384		/*
385		 * If we received a synchronous error when in userspace
386		 * kill the task. Firmware may report details of the fail
387		 * asynchronously, so we can't rely on the target and type
388		 * fields being valid here.
389		 */
390		printk(KERN_ERR "MCE: uncorrectable error, killing task "
391		       "%s:%d\n", current->comm, current->pid);
392
393		_exception(SIGBUS, regs, BUS_MCEERR_AR, regs->nip);
394		recovered = 1;
395	}
396
397	log_error((char *)err, ERR_TYPE_RTAS_LOG, 0);
398
399	return recovered;
400}
401
402/*
403 * Handle a machine check.
404 *
405 * Note that on Power 4 and beyond Firmware Non-Maskable Interrupts (fwnmi)
406 * should be present.  If so the handler which called us tells us if the
407 * error was recovered (never true if RI=0).
408 *
409 * On hardware prior to Power 4 these exceptions were asynchronous which
410 * means we can't tell exactly where it occurred and so we can't recover.
411 */
412int pSeries_machine_check_exception(struct pt_regs *regs)
413{
414	struct rtas_error_log *errp;
415
416	if (fwnmi_active) {
417		errp = fwnmi_get_errinfo(regs);
418		fwnmi_release_errinfo();
419		if (errp && recover_mce(regs, errp))
420			return 1;
421	}
422
423	return 0;
424}