Merge branch 'linus' into core/printk
[linux-2.6] / drivers / s390 / s390mach.c
1 /*
2  *  drivers/s390/s390mach.c
3  *   S/390 machine check handler
4  *
5  *  S390 version
6  *    Copyright (C) 2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
7  *    Author(s): Ingo Adlung (adlung@de.ibm.com)
8  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
9  */
10
11 #include <linux/init.h>
12 #include <linux/sched.h>
13 #include <linux/errno.h>
14 #include <linux/workqueue.h>
15 #include <linux/time.h>
16 #include <linux/device.h>
17 #include <linux/kthread.h>
18 #include <asm/etr.h>
19 #include <asm/lowcore.h>
20 #include <asm/cio.h>
21 #include "cio/cio.h"
22 #include "cio/chsc.h"
23 #include "cio/css.h"
24 #include "cio/chp.h"
25 #include "s390mach.h"
26
27 static struct semaphore m_sem;
28
29 static NORET_TYPE void
30 s390_handle_damage(char *msg)
31 {
32 #ifdef CONFIG_SMP
33         smp_send_stop();
34 #endif
35         disabled_wait((unsigned long) __builtin_return_address(0));
36         for(;;);
37 }
38
39 /*
40  * Retrieve CRWs and call function to handle event.
41  *
42  * Note : we currently process CRWs for io and chsc subchannels only
43  */
44 static int
45 s390_collect_crw_info(void *param)
46 {
47         struct crw crw[2];
48         int ccode;
49         struct semaphore *sem;
50         unsigned int chain;
51         int ignore;
52
53         sem = (struct semaphore *)param;
54 repeat:
55         ignore = down_interruptible(sem);
56         chain = 0;
57         while (1) {
58                 if (unlikely(chain > 1)) {
59                         struct crw tmp_crw;
60
61                         printk(KERN_WARNING"%s: Code does not support more "
62                                "than two chained crws; please report to "
63                                "linux390@de.ibm.com!\n", __func__);
64                         ccode = stcrw(&tmp_crw);
65                         printk(KERN_WARNING"%s: crw reports slct=%d, oflw=%d, "
66                                "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
67                                __func__, tmp_crw.slct, tmp_crw.oflw,
68                                tmp_crw.chn, tmp_crw.rsc, tmp_crw.anc,
69                                tmp_crw.erc, tmp_crw.rsid);
70                         printk(KERN_WARNING"%s: This was crw number %x in the "
71                                "chain\n", __func__, chain);
72                         if (ccode != 0)
73                                 break;
74                         chain = tmp_crw.chn ? chain + 1 : 0;
75                         continue;
76                 }
77                 ccode = stcrw(&crw[chain]);
78                 if (ccode != 0)
79                         break;
80                 printk(KERN_DEBUG "crw_info : CRW reports slct=%d, oflw=%d, "
81                        "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
82                        crw[chain].slct, crw[chain].oflw, crw[chain].chn,
83                        crw[chain].rsc, crw[chain].anc, crw[chain].erc,
84                        crw[chain].rsid);
85                 /* Check for overflows. */
86                 if (crw[chain].oflw) {
87                         pr_debug("%s: crw overflow detected!\n", __func__);
88                         css_schedule_eval_all();
89                         chain = 0;
90                         continue;
91                 }
92                 switch (crw[chain].rsc) {
93                 case CRW_RSC_SCH:
94                         if (crw[0].chn && !chain)
95                                 break;
96                         pr_debug("source is subchannel %04X\n", crw[0].rsid);
97                         css_process_crw(crw[0].rsid, chain ? crw[1].rsid : 0);
98                         break;
99                 case CRW_RSC_MONITOR:
100                         pr_debug("source is monitoring facility\n");
101                         break;
102                 case CRW_RSC_CPATH:
103                         pr_debug("source is channel path %02X\n", crw[0].rsid);
104                         /*
105                          * Check for solicited machine checks. These are
106                          * created by reset channel path and need not be
107                          * reported to the common I/O layer.
108                          */
109                         if (crw[chain].slct) {
110                                 pr_debug("solicited machine check for "
111                                          "channel path %02X\n", crw[0].rsid);
112                                 break;
113                         }
114                         switch (crw[0].erc) {
115                         case CRW_ERC_IPARM: /* Path has come. */
116                                 chp_process_crw(crw[0].rsid, 1);
117                                 break;
118                         case CRW_ERC_PERRI: /* Path has gone. */
119                         case CRW_ERC_PERRN:
120                                 chp_process_crw(crw[0].rsid, 0);
121                                 break;
122                         default:
123                                 pr_debug("Don't know how to handle erc=%x\n",
124                                          crw[0].erc);
125                         }
126                         break;
127                 case CRW_RSC_CONFIG:
128                         pr_debug("source is configuration-alert facility\n");
129                         break;
130                 case CRW_RSC_CSS:
131                         pr_debug("source is channel subsystem\n");
132                         chsc_process_crw();
133                         break;
134                 default:
135                         pr_debug("unknown source\n");
136                         break;
137                 }
138                 /* chain is always 0 or 1 here. */
139                 chain = crw[chain].chn ? chain + 1 : 0;
140         }
141         goto repeat;
142         return 0;
143 }
144
145 struct mcck_struct {
146         int kill_task;
147         int channel_report;
148         int warning;
149         unsigned long long mcck_code;
150 };
151
152 static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck);
153
154 /*
155  * Main machine check handler function. Will be called with interrupts enabled
156  * or disabled and machine checks enabled or disabled.
157  */
158 void
159 s390_handle_mcck(void)
160 {
161         unsigned long flags;
162         struct mcck_struct mcck;
163
164         /*
165          * Disable machine checks and get the current state of accumulated
166          * machine checks. Afterwards delete the old state and enable machine
167          * checks again.
168          */
169         local_irq_save(flags);
170         local_mcck_disable();
171         mcck = __get_cpu_var(cpu_mcck);
172         memset(&__get_cpu_var(cpu_mcck), 0, sizeof(struct mcck_struct));
173         clear_thread_flag(TIF_MCCK_PENDING);
174         local_mcck_enable();
175         local_irq_restore(flags);
176
177         if (mcck.channel_report)
178                 up(&m_sem);
179
180 #ifdef CONFIG_MACHCHK_WARNING
181 /*
182  * The warning may remain for a prolonged period on the bare iron.
183  * (actually till the machine is powered off, or until the problem is gone)
184  * So we just stop listening for the WARNING MCH and prevent continuously
185  * being interrupted.  One caveat is however, that we must do this per
186  * processor and cannot use the smp version of ctl_clear_bit().
187  * On VM we only get one interrupt per virtally presented machinecheck.
188  * Though one suffices, we may get one interrupt per (virtual) processor.
189  */
190         if (mcck.warning) {     /* WARNING pending ? */
191                 static int mchchk_wng_posted = 0;
192                 /*
193                  * Use single machine clear, as we cannot handle smp right now
194                  */
195                 __ctl_clear_bit(14, 24);        /* Disable WARNING MCH */
196                 if (xchg(&mchchk_wng_posted, 1) == 0)
197                         kill_cad_pid(SIGPWR, 1);
198         }
199 #endif
200
201         if (mcck.kill_task) {
202                 local_irq_enable();
203                 printk(KERN_EMERG "mcck: Terminating task because of machine "
204                        "malfunction (code 0x%016llx).\n", mcck.mcck_code);
205                 printk(KERN_EMERG "mcck: task: %s, pid: %d.\n",
206                        current->comm, current->pid);
207                 do_exit(SIGSEGV);
208         }
209 }
210 EXPORT_SYMBOL_GPL(s390_handle_mcck);
211
212 /*
213  * returns 0 if all registers could be validated
214  * returns 1 otherwise
215  */
216 static int
217 s390_revalidate_registers(struct mci *mci)
218 {
219         int kill_task;
220         u64 tmpclock;
221         u64 zero;
222         void *fpt_save_area, *fpt_creg_save_area;
223
224         kill_task = 0;
225         zero = 0;
226         /* General purpose registers */
227         if (!mci->gr)
228                 /*
229                  * General purpose registers couldn't be restored and have
230                  * unknown contents. Process needs to be terminated.
231                  */
232                 kill_task = 1;
233
234         /* Revalidate floating point registers */
235         if (!mci->fp)
236                 /*
237                  * Floating point registers can't be restored and
238                  * therefore the process needs to be terminated.
239                  */
240                 kill_task = 1;
241
242 #ifndef CONFIG_64BIT
243         asm volatile(
244                 "       ld      0,0(%0)\n"
245                 "       ld      2,8(%0)\n"
246                 "       ld      4,16(%0)\n"
247                 "       ld      6,24(%0)"
248                 : : "a" (&S390_lowcore.floating_pt_save_area));
249 #endif
250
251         if (MACHINE_HAS_IEEE) {
252 #ifdef CONFIG_64BIT
253                 fpt_save_area = &S390_lowcore.floating_pt_save_area;
254                 fpt_creg_save_area = &S390_lowcore.fpt_creg_save_area;
255 #else
256                 fpt_save_area = (void *) S390_lowcore.extended_save_area_addr;
257                 fpt_creg_save_area = fpt_save_area+128;
258 #endif
259                 /* Floating point control register */
260                 if (!mci->fc) {
261                         /*
262                          * Floating point control register can't be restored.
263                          * Task will be terminated.
264                          */
265                         asm volatile("lfpc 0(%0)" : : "a" (&zero), "m" (zero));
266                         kill_task = 1;
267
268                 } else
269                         asm volatile("lfpc 0(%0)" : : "a" (fpt_creg_save_area));
270
271                 asm volatile(
272                         "       ld      0,0(%0)\n"
273                         "       ld      1,8(%0)\n"
274                         "       ld      2,16(%0)\n"
275                         "       ld      3,24(%0)\n"
276                         "       ld      4,32(%0)\n"
277                         "       ld      5,40(%0)\n"
278                         "       ld      6,48(%0)\n"
279                         "       ld      7,56(%0)\n"
280                         "       ld      8,64(%0)\n"
281                         "       ld      9,72(%0)\n"
282                         "       ld      10,80(%0)\n"
283                         "       ld      11,88(%0)\n"
284                         "       ld      12,96(%0)\n"
285                         "       ld      13,104(%0)\n"
286                         "       ld      14,112(%0)\n"
287                         "       ld      15,120(%0)\n"
288                         : : "a" (fpt_save_area));
289         }
290
291         /* Revalidate access registers */
292         asm volatile(
293                 "       lam     0,15,0(%0)"
294                 : : "a" (&S390_lowcore.access_regs_save_area));
295         if (!mci->ar)
296                 /*
297                  * Access registers have unknown contents.
298                  * Terminating task.
299                  */
300                 kill_task = 1;
301
302         /* Revalidate control registers */
303         if (!mci->cr)
304                 /*
305                  * Control registers have unknown contents.
306                  * Can't recover and therefore stopping machine.
307                  */
308                 s390_handle_damage("invalid control registers.");
309         else
310 #ifdef CONFIG_64BIT
311                 asm volatile(
312                         "       lctlg   0,15,0(%0)"
313                         : : "a" (&S390_lowcore.cregs_save_area));
314 #else
315                 asm volatile(
316                         "       lctl    0,15,0(%0)"
317                         : : "a" (&S390_lowcore.cregs_save_area));
318 #endif
319
320         /*
321          * We don't even try to revalidate the TOD register, since we simply
322          * can't write something sensible into that register.
323          */
324
325 #ifdef CONFIG_64BIT
326         /*
327          * See if we can revalidate the TOD programmable register with its
328          * old contents (should be zero) otherwise set it to zero.
329          */
330         if (!mci->pr)
331                 asm volatile(
332                         "       sr      0,0\n"
333                         "       sckpf"
334                         : : : "0", "cc");
335         else
336                 asm volatile(
337                         "       l       0,0(%0)\n"
338                         "       sckpf"
339                         : : "a" (&S390_lowcore.tod_progreg_save_area)
340                         : "0", "cc");
341 #endif
342
343         /* Revalidate clock comparator register */
344         asm volatile(
345                 "       stck    0(%1)\n"
346                 "       sckc    0(%1)"
347                 : "=m" (tmpclock) : "a" (&(tmpclock)) : "cc", "memory");
348
349         /* Check if old PSW is valid */
350         if (!mci->wp)
351                 /*
352                  * Can't tell if we come from user or kernel mode
353                  * -> stopping machine.
354                  */
355                 s390_handle_damage("old psw invalid.");
356
357         if (!mci->ms || !mci->pm || !mci->ia)
358                 kill_task = 1;
359
360         return kill_task;
361 }
362
363 #define MAX_IPD_COUNT   29
364 #define MAX_IPD_TIME    (5 * 60 * USEC_PER_SEC) /* 5 minutes */
365
366 /*
367  * machine check handler.
368  */
369 void
370 s390_do_machine_check(struct pt_regs *regs)
371 {
372         static DEFINE_SPINLOCK(ipd_lock);
373         static unsigned long long last_ipd;
374         static int ipd_count;
375         unsigned long long tmp;
376         struct mci *mci;
377         struct mcck_struct *mcck;
378         int umode;
379
380         lockdep_off();
381
382         mci = (struct mci *) &S390_lowcore.mcck_interruption_code;
383         mcck = &__get_cpu_var(cpu_mcck);
384         umode = user_mode(regs);
385
386         if (mci->sd)
387                 /* System damage -> stopping machine */
388                 s390_handle_damage("received system damage machine check.");
389
390         if (mci->pd) {
391                 if (mci->b) {
392                         /* Processing backup -> verify if we can survive this */
393                         u64 z_mcic, o_mcic, t_mcic;
394 #ifdef CONFIG_64BIT
395                         z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29);
396                         o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
397                                   1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
398                                   1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 |
399                                   1ULL<<16);
400 #else
401                         z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<57 | 1ULL<<50 |
402                                   1ULL<<29);
403                         o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
404                                   1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
405                                   1ULL<<30 | 1ULL<<20 | 1ULL<<17 | 1ULL<<16);
406 #endif
407                         t_mcic = *(u64 *)mci;
408
409                         if (((t_mcic & z_mcic) != 0) ||
410                             ((t_mcic & o_mcic) != o_mcic)) {
411                                 s390_handle_damage("processing backup machine "
412                                                    "check with damage.");
413                         }
414
415                         /*
416                          * Nullifying exigent condition, therefore we might
417                          * retry this instruction.
418                          */
419
420                         spin_lock(&ipd_lock);
421
422                         tmp = get_clock();
423
424                         if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME)
425                                 ipd_count++;
426                         else
427                                 ipd_count = 1;
428
429                         last_ipd = tmp;
430
431                         if (ipd_count == MAX_IPD_COUNT)
432                                 s390_handle_damage("too many ipd retries.");
433
434                         spin_unlock(&ipd_lock);
435                 }
436                 else {
437                         /* Processing damage -> stopping machine */
438                         s390_handle_damage("received instruction processing "
439                                            "damage machine check.");
440                 }
441         }
442         if (s390_revalidate_registers(mci)) {
443                 if (umode) {
444                         /*
445                          * Couldn't restore all register contents while in
446                          * user mode -> mark task for termination.
447                          */
448                         mcck->kill_task = 1;
449                         mcck->mcck_code = *(unsigned long long *) mci;
450                         set_thread_flag(TIF_MCCK_PENDING);
451                 }
452                 else
453                         /*
454                          * Couldn't restore all register contents while in
455                          * kernel mode -> stopping machine.
456                          */
457                         s390_handle_damage("unable to revalidate registers.");
458         }
459
460         if (mci->cd) {
461                 /* Timing facility damage */
462                 s390_handle_damage("TOD clock damaged");
463         }
464
465         if (mci->ed && mci->ec) {
466                 /* External damage */
467                 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SYNC))
468                         etr_sync_check();
469                 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SWITCH))
470                         etr_switch_to_local();
471         }
472
473         if (mci->se)
474                 /* Storage error uncorrected */
475                 s390_handle_damage("received storage error uncorrected "
476                                    "machine check.");
477
478         if (mci->ke)
479                 /* Storage key-error uncorrected */
480                 s390_handle_damage("received storage key-error uncorrected "
481                                    "machine check.");
482
483         if (mci->ds && mci->fa)
484                 /* Storage degradation */
485                 s390_handle_damage("received storage degradation machine "
486                                    "check.");
487
488         if (mci->cp) {
489                 /* Channel report word pending */
490                 mcck->channel_report = 1;
491                 set_thread_flag(TIF_MCCK_PENDING);
492         }
493
494         if (mci->w) {
495                 /* Warning pending */
496                 mcck->warning = 1;
497                 set_thread_flag(TIF_MCCK_PENDING);
498         }
499         lockdep_on();
500 }
501
502 /*
503  * s390_init_machine_check
504  *
505  * initialize machine check handling
506  */
507 static int
508 machine_check_init(void)
509 {
510         init_MUTEX_LOCKED(&m_sem);
511         ctl_set_bit(14, 25);    /* enable external damage MCH */
512         ctl_set_bit(14, 27);    /* enable system recovery MCH */
513 #ifdef CONFIG_MACHCHK_WARNING
514         ctl_set_bit(14, 24);    /* enable warning MCH */
515 #endif
516         return 0;
517 }
518
519 /*
520  * Initialize the machine check handler really early to be able to
521  * catch all machine checks that happen during boot
522  */
523 arch_initcall(machine_check_init);
524
525 /*
526  * Machine checks for the channel subsystem must be enabled
527  * after the channel subsystem is initialized
528  */
529 static int __init
530 machine_check_crw_init (void)
531 {
532         struct task_struct *task;
533
534         task = kthread_run(s390_collect_crw_info, &m_sem, "kmcheck");
535         if (IS_ERR(task))
536                 return PTR_ERR(task);
537         ctl_set_bit(14, 28);    /* enable channel report MCH */
538         return 0;
539 }
540
541 device_initcall (machine_check_crw_init);