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

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  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 #include <linux/irq_work.h>
 26 
 27 #include <asm/machdep.h>
 28 #include <asm/rtas.h>
 29 #include <asm/firmware.h>
 30 
 31 #include "pseries.h"
 32 
 33 static unsigned char ras_log_buf[RTAS_ERROR_LOG_MAX];
 34 static DEFINE_SPINLOCK(ras_log_buf_lock);
 35 
 36 static int ras_check_exception_token;
 37 
 38 static void mce_process_errlog_event(struct irq_work *work);
 39 static struct irq_work mce_errlog_process_work = {
 40         .func = mce_process_errlog_event,
 41 };
 42 
 43 #define EPOW_SENSOR_TOKEN       9
 44 #define EPOW_SENSOR_INDEX       0
 45 
 46 /* EPOW events counter variable */
 47 static int num_epow_events;
 48 
 49 static irqreturn_t ras_hotplug_interrupt(int irq, void *dev_id);
 50 static irqreturn_t ras_epow_interrupt(int irq, void *dev_id);
 51 static irqreturn_t ras_error_interrupt(int irq, void *dev_id);
 52 
 53 
 54 /*
 55  * Enable the hotplug interrupt late because processing them may touch other
 56  * devices or systems (e.g. hugepages) that have not been initialized at the
 57  * subsys stage.
 58  */
 59 int __init init_ras_hotplug_IRQ(void)
 60 {
 61         struct device_node *np;
 62 
 63         /* Hotplug Events */
 64         np = of_find_node_by_path("/event-sources/hot-plug-events");
 65         if (np != NULL) {
 66                 if (dlpar_workqueue_init() == 0)
 67                         request_event_sources_irqs(np, ras_hotplug_interrupt,
 68                                                    "RAS_HOTPLUG");
 69                 of_node_put(np);
 70         }
 71 
 72         return 0;
 73 }
 74 machine_late_initcall(pseries, init_ras_hotplug_IRQ);
 75 
 76 /*
 77  * Initialize handlers for the set of interrupts caused by hardware errors
 78  * and power system events.
 79  */
 80 static int __init init_ras_IRQ(void)
 81 {
 82         struct device_node *np;
 83 
 84         ras_check_exception_token = rtas_token("check-exception");
 85 
 86         /* Internal Errors */
 87         np = of_find_node_by_path("/event-sources/internal-errors");
 88         if (np != NULL) {
 89                 request_event_sources_irqs(np, ras_error_interrupt,
 90                                            "RAS_ERROR");
 91                 of_node_put(np);
 92         }
 93 
 94         /* EPOW Events */
 95         np = of_find_node_by_path("/event-sources/epow-events");
 96         if (np != NULL) {
 97                 request_event_sources_irqs(np, ras_epow_interrupt, "RAS_EPOW");
 98                 of_node_put(np);
 99         }
100 
101         return 0;
102 }
103 machine_subsys_initcall(pseries, init_ras_IRQ);
104 
105 #define EPOW_SHUTDOWN_NORMAL                            1
106 #define EPOW_SHUTDOWN_ON_UPS                            2
107 #define EPOW_SHUTDOWN_LOSS_OF_CRITICAL_FUNCTIONS        3
108 #define EPOW_SHUTDOWN_AMBIENT_TEMPERATURE_TOO_HIGH      4
109 
110 static void handle_system_shutdown(char event_modifier)
111 {
112         switch (event_modifier) {
113         case EPOW_SHUTDOWN_NORMAL:
114                 pr_emerg("Power off requested\n");
115                 orderly_poweroff(true);
116                 break;
117 
118         case EPOW_SHUTDOWN_ON_UPS:
119                 pr_emerg("Loss of system power detected. System is running on"
120                          " UPS/battery. Check RTAS error log for details\n");
121                 orderly_poweroff(true);
122                 break;
123 
124         case EPOW_SHUTDOWN_LOSS_OF_CRITICAL_FUNCTIONS:
125                 pr_emerg("Loss of system critical functions detected. Check"
126                          " RTAS error log for details\n");
127                 orderly_poweroff(true);
128                 break;
129 
130         case EPOW_SHUTDOWN_AMBIENT_TEMPERATURE_TOO_HIGH:
131                 pr_emerg("High ambient temperature detected. Check RTAS"
132                          " error log for details\n");
133                 orderly_poweroff(true);
134                 break;
135 
136         default:
137                 pr_err("Unknown power/cooling shutdown event (modifier = %d)\n",
138                         event_modifier);
139         }
140 }
141 
142 struct epow_errorlog {
143         unsigned char sensor_value;
144         unsigned char event_modifier;
145         unsigned char extended_modifier;
146         unsigned char reserved;
147         unsigned char platform_reason;
148 };
149 
150 #define EPOW_RESET                      0
151 #define EPOW_WARN_COOLING               1
152 #define EPOW_WARN_POWER                 2
153 #define EPOW_SYSTEM_SHUTDOWN            3
154 #define EPOW_SYSTEM_HALT                4
155 #define EPOW_MAIN_ENCLOSURE             5
156 #define EPOW_POWER_OFF                  7
157 
158 static void rtas_parse_epow_errlog(struct rtas_error_log *log)
159 {
160         struct pseries_errorlog *pseries_log;
161         struct epow_errorlog *epow_log;
162         char action_code;
163         char modifier;
164 
165         pseries_log = get_pseries_errorlog(log, PSERIES_ELOG_SECT_ID_EPOW);
166         if (pseries_log == NULL)
167                 return;
168 
169         epow_log = (struct epow_errorlog *)pseries_log->data;
170         action_code = epow_log->sensor_value & 0xF;     /* bottom 4 bits */
171         modifier = epow_log->event_modifier & 0xF;      /* bottom 4 bits */
172 
173         switch (action_code) {
174         case EPOW_RESET:
175                 if (num_epow_events) {
176                         pr_info("Non critical power/cooling issue cleared\n");
177                         num_epow_events--;
178                 }
179                 break;
180 
181         case EPOW_WARN_COOLING:
182                 pr_info("Non-critical cooling issue detected. Check RTAS error"
183                         " log for details\n");
184                 break;
185 
186         case EPOW_WARN_POWER:
187                 pr_info("Non-critical power issue detected. Check RTAS error"
188                         " log for details\n");
189                 break;
190 
191         case EPOW_SYSTEM_SHUTDOWN:
192                 handle_system_shutdown(epow_log->event_modifier);
193                 break;
194 
195         case EPOW_SYSTEM_HALT:
196                 pr_emerg("Critical power/cooling issue detected. Check RTAS"
197                          " error log for details. Powering off.\n");
198                 orderly_poweroff(true);
199                 break;
200 
201         case EPOW_MAIN_ENCLOSURE:
202         case EPOW_POWER_OFF:
203                 pr_emerg("System about to lose power. Check RTAS error log "
204                          " for details. Powering off immediately.\n");
205                 emergency_sync();
206                 kernel_power_off();
207                 break;
208 
209         default:
210                 pr_err("Unknown power/cooling event (action code  = %d)\n",
211                         action_code);
212         }
213 
214         /* Increment epow events counter variable */
215         if (action_code != EPOW_RESET)
216                 num_epow_events++;
217 }
218 
219 static irqreturn_t ras_hotplug_interrupt(int irq, void *dev_id)
220 {
221         struct pseries_errorlog *pseries_log;
222         struct pseries_hp_errorlog *hp_elog;
223 
224         spin_lock(&ras_log_buf_lock);
225 
226         rtas_call(ras_check_exception_token, 6, 1, NULL,
227                   RTAS_VECTOR_EXTERNAL_INTERRUPT, virq_to_hw(irq),
228                   RTAS_HOTPLUG_EVENTS, 0, __pa(&ras_log_buf),
229                   rtas_get_error_log_max());
230 
231         pseries_log = get_pseries_errorlog((struct rtas_error_log *)ras_log_buf,
232                                            PSERIES_ELOG_SECT_ID_HOTPLUG);
233         hp_elog = (struct pseries_hp_errorlog *)pseries_log->data;
234 
235         /*
236          * Since PCI hotplug is not currently supported on pseries, put PCI
237          * hotplug events on the ras_log_buf to be handled by rtas_errd.
238          */
239         if (hp_elog->resource == PSERIES_HP_ELOG_RESOURCE_MEM ||
240             hp_elog->resource == PSERIES_HP_ELOG_RESOURCE_CPU)
241                 queue_hotplug_event(hp_elog, NULL, NULL);
242         else
243                 log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, 0);
244 
245         spin_unlock(&ras_log_buf_lock);
246         return IRQ_HANDLED;
247 }
248 
249 /* Handle environmental and power warning (EPOW) interrupts. */
250 static irqreturn_t ras_epow_interrupt(int irq, void *dev_id)
251 {
252         int status;
253         int state;
254         int critical;
255 
256         status = rtas_get_sensor_fast(EPOW_SENSOR_TOKEN, EPOW_SENSOR_INDEX,
257                                       &state);
258 
259         if (state > 3)
260                 critical = 1;           /* Time Critical */
261         else
262                 critical = 0;
263 
264         spin_lock(&ras_log_buf_lock);
265 
266         status = rtas_call(ras_check_exception_token, 6, 1, NULL,
267                            RTAS_VECTOR_EXTERNAL_INTERRUPT,
268                            virq_to_hw(irq),
269                            RTAS_EPOW_WARNING,
270                            critical, __pa(&ras_log_buf),
271                                 rtas_get_error_log_max());
272 
273         log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, 0);
274 
275         rtas_parse_epow_errlog((struct rtas_error_log *)ras_log_buf);
276 
277         spin_unlock(&ras_log_buf_lock);
278         return IRQ_HANDLED;
279 }
280 
281 /*
282  * Handle hardware error interrupts.
283  *
284  * RTAS check-exception is called to collect data on the exception.  If
285  * the error is deemed recoverable, we log a warning and return.
286  * For nonrecoverable errors, an error is logged and we stop all processing
287  * as quickly as possible in order to prevent propagation of the failure.
288  */
289 static irqreturn_t ras_error_interrupt(int irq, void *dev_id)
290 {
291         struct rtas_error_log *rtas_elog;
292         int status;
293         int fatal;
294 
295         spin_lock(&ras_log_buf_lock);
296 
297         status = rtas_call(ras_check_exception_token, 6, 1, NULL,
298                            RTAS_VECTOR_EXTERNAL_INTERRUPT,
299                            virq_to_hw(irq),
300                            RTAS_INTERNAL_ERROR, 1 /* Time Critical */,
301                            __pa(&ras_log_buf),
302                                 rtas_get_error_log_max());
303 
304         rtas_elog = (struct rtas_error_log *)ras_log_buf;
305 
306         if (status == 0 &&
307             rtas_error_severity(rtas_elog) >= RTAS_SEVERITY_ERROR_SYNC)
308                 fatal = 1;
309         else
310                 fatal = 0;
311 
312         /* format and print the extended information */
313         log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, fatal);
314 
315         if (fatal) {
316                 pr_emerg("Fatal hardware error detected. Check RTAS error"
317                          " log for details. Powering off immediately\n");
318                 emergency_sync();
319                 kernel_power_off();
320         } else {
321                 pr_err("Recoverable hardware error detected\n");
322         }
323 
324         spin_unlock(&ras_log_buf_lock);
325         return IRQ_HANDLED;
326 }
327 
328 /*
329  * Some versions of FWNMI place the buffer inside the 4kB page starting at
330  * 0x7000. Other versions place it inside the rtas buffer. We check both.
331  */
332 #define VALID_FWNMI_BUFFER(A) \
333         ((((A) >= 0x7000) && ((A) < 0x7ff0)) || \
334         (((A) >= rtas.base) && ((A) < (rtas.base + rtas.size - 16))))
335 
336 static inline struct rtas_error_log *fwnmi_get_errlog(void)
337 {
338         return (struct rtas_error_log *)local_paca->mce_data_buf;
339 }
340 
341 /*
342  * Get the error information for errors coming through the
343  * FWNMI vectors.  The pt_regs' r3 will be updated to reflect
344  * the actual r3 if possible, and a ptr to the error log entry
345  * will be returned if found.
346  *
347  * Use one buffer mce_data_buf per cpu to store RTAS error.
348  *
349  * The mce_data_buf does not have any locks or protection around it,
350  * if a second machine check comes in, or a system reset is done
351  * before we have logged the error, then we will get corruption in the
352  * error log.  This is preferable over holding off on calling
353  * ibm,nmi-interlock which would result in us checkstopping if a
354  * second machine check did come in.
355  */
356 static struct rtas_error_log *fwnmi_get_errinfo(struct pt_regs *regs)
357 {
358         unsigned long *savep;
359         struct rtas_error_log *h;
360 
361         /* Mask top two bits */
362         regs->gpr[3] &= ~(0x3UL << 62);
363 
364         if (!VALID_FWNMI_BUFFER(regs->gpr[3])) {
365                 printk(KERN_ERR "FWNMI: corrupt r3 0x%016lx\n", regs->gpr[3]);
366                 return NULL;
367         }
368 
369         savep = __va(regs->gpr[3]);
370         regs->gpr[3] = be64_to_cpu(savep[0]);   /* restore original r3 */
371 
372         h = (struct rtas_error_log *)&savep[1];
373         /* Use the per cpu buffer from paca to store rtas error log */
374         memset(local_paca->mce_data_buf, 0, RTAS_ERROR_LOG_MAX);
375         if (!rtas_error_extended(h)) {
376                 memcpy(local_paca->mce_data_buf, h, sizeof(__u64));
377         } else {
378                 int len, error_log_length;
379 
380                 error_log_length = 8 + rtas_error_extended_log_length(h);
381                 len = min_t(int, error_log_length, RTAS_ERROR_LOG_MAX);
382                 memcpy(local_paca->mce_data_buf, h, len);
383         }
384 
385         return (struct rtas_error_log *)local_paca->mce_data_buf;
386 }
387 
388 /* Call this when done with the data returned by FWNMI_get_errinfo.
389  * It will release the saved data area for other CPUs in the
390  * partition to receive FWNMI errors.
391  */
392 static void fwnmi_release_errinfo(void)
393 {
394         int ret = rtas_call(rtas_token("ibm,nmi-interlock"), 0, 1, NULL);
395         if (ret != 0)
396                 printk(KERN_ERR "FWNMI: nmi-interlock failed: %d\n", ret);
397 }
398 
399 int pSeries_system_reset_exception(struct pt_regs *regs)
400 {
401 #ifdef __LITTLE_ENDIAN__
402         /*
403          * Some firmware byteswaps SRR registers and gives incorrect SRR1. Try
404          * to detect the bad SRR1 pattern here. Flip the NIP back to correct
405          * endian for reporting purposes. Unfortunately the MSR can't be fixed,
406          * so clear it. It will be missing MSR_RI so we won't try to recover.
407          */
408         if ((be64_to_cpu(regs->msr) &
409                         (MSR_LE|MSR_RI|MSR_DR|MSR_IR|MSR_ME|MSR_PR|
410                          MSR_ILE|MSR_HV|MSR_SF)) == (MSR_DR|MSR_SF)) {
411                 regs->nip = be64_to_cpu((__be64)regs->nip);
412                 regs->msr = 0;
413         }
414 #endif
415 
416         if (fwnmi_active) {
417                 struct rtas_error_log *errhdr = fwnmi_get_errinfo(regs);
418                 if (errhdr) {
419                         /* XXX Should look at FWNMI information */
420                 }
421                 fwnmi_release_errinfo();
422         }
423 
424         if (smp_handle_nmi_ipi(regs))
425                 return 1;
426 
427         return 0; /* need to perform reset */
428 }
429 
430 /*
431  * Process MCE rtas errlog event.
432  */
433 static void mce_process_errlog_event(struct irq_work *work)
434 {
435         struct rtas_error_log *err;
436 
437         err = fwnmi_get_errlog();
438         log_error((char *)err, ERR_TYPE_RTAS_LOG, 0);
439 }
440 
441 /*
442  * See if we can recover from a machine check exception.
443  * This is only called on power4 (or above) and only via
444  * the Firmware Non-Maskable Interrupts (fwnmi) handler
445  * which provides the error analysis for us.
446  *
447  * Return 1 if corrected (or delivered a signal).
448  * Return 0 if there is nothing we can do.
449  */
450 static int recover_mce(struct pt_regs *regs, struct rtas_error_log *err)
451 {
452         int recovered = 0;
453         int disposition = rtas_error_disposition(err);
454 
455         if (!(regs->msr & MSR_RI)) {
456                 /* If MSR_RI isn't set, we cannot recover */
457                 recovered = 0;
458 
459         } else if (disposition == RTAS_DISP_FULLY_RECOVERED) {
460                 /* Platform corrected itself */
461                 recovered = 1;
462 
463         } else if (disposition == RTAS_DISP_LIMITED_RECOVERY) {
464                 /* Platform corrected itself but could be degraded */
465                 printk(KERN_ERR "MCE: limited recovery, system may "
466                        "be degraded\n");
467                 recovered = 1;
468 
469         } else if (user_mode(regs) && !is_global_init(current) &&
470                    rtas_error_severity(err) == RTAS_SEVERITY_ERROR_SYNC) {
471 
472                 /*
473                  * If we received a synchronous error when in userspace
474                  * kill the task. Firmware may report details of the fail
475                  * asynchronously, so we can't rely on the target and type
476                  * fields being valid here.
477                  */
478                 printk(KERN_ERR "MCE: uncorrectable error, killing task "
479                        "%s:%d\n", current->comm, current->pid);
480 
481                 _exception(SIGBUS, regs, BUS_MCEERR_AR, regs->nip);
482                 recovered = 1;
483         }
484 
485         /* Queue irq work to log this rtas event later. */
486         irq_work_queue(&mce_errlog_process_work);
487 
488         return recovered;
489 }
490 
491 /*
492  * Handle a machine check.
493  *
494  * Note that on Power 4 and beyond Firmware Non-Maskable Interrupts (fwnmi)
495  * should be present.  If so the handler which called us tells us if the
496  * error was recovered (never true if RI=0).
497  *
498  * On hardware prior to Power 4 these exceptions were asynchronous which
499  * means we can't tell exactly where it occurred and so we can't recover.
500  */
501 int pSeries_machine_check_exception(struct pt_regs *regs)
502 {
503         struct rtas_error_log *errp;
504 
505         if (fwnmi_active) {
506                 errp = fwnmi_get_errinfo(regs);
507                 fwnmi_release_errinfo();
508                 if (errp && recover_mce(regs, errp))
509                         return 1;
510         }
511 
512         return 0;
513 }
514 

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