[GFS2] Fix up merge of Linus' kernel into GFS2
[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/kthread.h>
17
18 #include <asm/lowcore.h>
19
20 #include "s390mach.h"
21
22 static struct semaphore m_sem;
23
24 extern int css_process_crw(int, int);
25 extern int chsc_process_crw(void);
26 extern int chp_process_crw(int, int);
27 extern void css_reiterate_subchannels(void);
28
29 extern struct workqueue_struct *slow_path_wq;
30 extern struct work_struct slow_path_work;
31
32 static NORET_TYPE void
33 s390_handle_damage(char *msg)
34 {
35 #ifdef CONFIG_SMP
36         smp_send_stop();
37 #endif
38         disabled_wait((unsigned long) __builtin_return_address(0));
39         for(;;);
40 }
41
42 /*
43  * Retrieve CRWs and call function to handle event.
44  *
45  * Note : we currently process CRWs for io and chsc subchannels only
46  */
47 static int
48 s390_collect_crw_info(void *param)
49 {
50         struct crw crw[2];
51         int ccode, ret, slow;
52         struct semaphore *sem;
53         unsigned int chain;
54
55         sem = (struct semaphore *)param;
56 repeat:
57         down_interruptible(sem);
58         slow = 0;
59         chain = 0;
60         while (1) {
61                 if (unlikely(chain > 1)) {
62                         struct crw tmp_crw;
63
64                         printk(KERN_WARNING"%s: Code does not support more "
65                                "than two chained crws; please report to "
66                                "linux390@de.ibm.com!\n", __FUNCTION__);
67                         ccode = stcrw(&tmp_crw);
68                         printk(KERN_WARNING"%s: crw reports slct=%d, oflw=%d, "
69                                "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
70                                __FUNCTION__, tmp_crw.slct, tmp_crw.oflw,
71                                tmp_crw.chn, tmp_crw.rsc, tmp_crw.anc,
72                                tmp_crw.erc, tmp_crw.rsid);
73                         printk(KERN_WARNING"%s: This was crw number %x in the "
74                                "chain\n", __FUNCTION__, chain);
75                         if (ccode != 0)
76                                 break;
77                         chain = tmp_crw.chn ? chain + 1 : 0;
78                         continue;
79                 }
80                 ccode = stcrw(&crw[chain]);
81                 if (ccode != 0)
82                         break;
83                 printk(KERN_DEBUG "crw_info : CRW reports slct=%d, oflw=%d, "
84                        "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
85                        crw[chain].slct, crw[chain].oflw, crw[chain].chn,
86                        crw[chain].rsc, crw[chain].anc, crw[chain].erc,
87                        crw[chain].rsid);
88                 /* Check for overflows. */
89                 if (crw[chain].oflw) {
90                         pr_debug("%s: crw overflow detected!\n", __FUNCTION__);
91                         css_reiterate_subchannels();
92                         chain = 0;
93                         slow = 1;
94                         continue;
95                 }
96                 switch (crw[chain].rsc) {
97                 case CRW_RSC_SCH:
98                         if (crw[0].chn && !chain)
99                                 break;
100                         pr_debug("source is subchannel %04X\n", crw[0].rsid);
101                         ret = css_process_crw (crw[0].rsid,
102                                                chain ? crw[1].rsid : 0);
103                         if (ret == -EAGAIN)
104                                 slow = 1;
105                         break;
106                 case CRW_RSC_MONITOR:
107                         pr_debug("source is monitoring facility\n");
108                         break;
109                 case CRW_RSC_CPATH:
110                         pr_debug("source is channel path %02X\n", crw[0].rsid);
111                         /*
112                          * Check for solicited machine checks. These are
113                          * created by reset channel path and need not be
114                          * reported to the common I/O layer.
115                          */
116                         if (crw[chain].slct) {
117                                 pr_debug("solicited machine check for "
118                                          "channel path %02X\n", crw[0].rsid);
119                                 break;
120                         }
121                         switch (crw[0].erc) {
122                         case CRW_ERC_IPARM: /* Path has come. */
123                                 ret = chp_process_crw(crw[0].rsid, 1);
124                                 break;
125                         case CRW_ERC_PERRI: /* Path has gone. */
126                         case CRW_ERC_PERRN:
127                                 ret = chp_process_crw(crw[0].rsid, 0);
128                                 break;
129                         default:
130                                 pr_debug("Don't know how to handle erc=%x\n",
131                                          crw[0].erc);
132                                 ret = 0;
133                         }
134                         if (ret == -EAGAIN)
135                                 slow = 1;
136                         break;
137                 case CRW_RSC_CONFIG:
138                         pr_debug("source is configuration-alert facility\n");
139                         break;
140                 case CRW_RSC_CSS:
141                         pr_debug("source is channel subsystem\n");
142                         ret = chsc_process_crw();
143                         if (ret == -EAGAIN)
144                                 slow = 1;
145                         break;
146                 default:
147                         pr_debug("unknown source\n");
148                         break;
149                 }
150                 /* chain is always 0 or 1 here. */
151                 chain = crw[chain].chn ? chain + 1 : 0;
152         }
153         if (slow)
154                 queue_work(slow_path_wq, &slow_path_work);
155         goto repeat;
156         return 0;
157 }
158
159 struct mcck_struct {
160         int kill_task;
161         int channel_report;
162         int warning;
163         unsigned long long mcck_code;
164 };
165
166 static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck);
167
168 /*
169  * Main machine check handler function. Will be called with interrupts enabled
170  * or disabled and machine checks enabled or disabled.
171  */
172 void
173 s390_handle_mcck(void)
174 {
175         unsigned long flags;
176         struct mcck_struct mcck;
177
178         /*
179          * Disable machine checks and get the current state of accumulated
180          * machine checks. Afterwards delete the old state and enable machine
181          * checks again.
182          */
183         local_irq_save(flags);
184         local_mcck_disable();
185         mcck = __get_cpu_var(cpu_mcck);
186         memset(&__get_cpu_var(cpu_mcck), 0, sizeof(struct mcck_struct));
187         clear_thread_flag(TIF_MCCK_PENDING);
188         local_mcck_enable();
189         local_irq_restore(flags);
190
191         if (mcck.channel_report)
192                 up(&m_sem);
193
194 #ifdef CONFIG_MACHCHK_WARNING
195 /*
196  * The warning may remain for a prolonged period on the bare iron.
197  * (actually till the machine is powered off, or until the problem is gone)
198  * So we just stop listening for the WARNING MCH and prevent continuously
199  * being interrupted.  One caveat is however, that we must do this per
200  * processor and cannot use the smp version of ctl_clear_bit().
201  * On VM we only get one interrupt per virtally presented machinecheck.
202  * Though one suffices, we may get one interrupt per (virtual) processor.
203  */
204         if (mcck.warning) {     /* WARNING pending ? */
205                 static int mchchk_wng_posted = 0;
206                 /*
207                  * Use single machine clear, as we cannot handle smp right now
208                  */
209                 __ctl_clear_bit(14, 24);        /* Disable WARNING MCH */
210                 if (xchg(&mchchk_wng_posted, 1) == 0)
211                         kill_proc(1, SIGPWR, 1);
212         }
213 #endif
214
215         if (mcck.kill_task) {
216                 local_irq_enable();
217                 printk(KERN_EMERG "mcck: Terminating task because of machine "
218                        "malfunction (code 0x%016llx).\n", mcck.mcck_code);
219                 printk(KERN_EMERG "mcck: task: %s, pid: %d.\n",
220                        current->comm, current->pid);
221                 do_exit(SIGSEGV);
222         }
223 }
224
225 /*
226  * returns 0 if all registers could be validated
227  * returns 1 otherwise
228  */
229 static int
230 s390_revalidate_registers(struct mci *mci)
231 {
232         int kill_task;
233         u64 tmpclock;
234         u64 zero;
235         void *fpt_save_area, *fpt_creg_save_area;
236
237         kill_task = 0;
238         zero = 0;
239         /* General purpose registers */
240         if (!mci->gr)
241                 /*
242                  * General purpose registers couldn't be restored and have
243                  * unknown contents. Process needs to be terminated.
244                  */
245                 kill_task = 1;
246
247         /* Revalidate floating point registers */
248         if (!mci->fp)
249                 /*
250                  * Floating point registers can't be restored and
251                  * therefore the process needs to be terminated.
252                  */
253                 kill_task = 1;
254
255 #ifndef CONFIG_64BIT
256         asm volatile("ld 0,0(%0)\n"
257                      "ld 2,8(%0)\n"
258                      "ld 4,16(%0)\n"
259                      "ld 6,24(%0)"
260                      : : "a" (&S390_lowcore.floating_pt_save_area));
261 #endif
262
263         if (MACHINE_HAS_IEEE) {
264 #ifdef CONFIG_64BIT
265                 fpt_save_area = &S390_lowcore.floating_pt_save_area;
266                 fpt_creg_save_area = &S390_lowcore.fpt_creg_save_area;
267 #else
268                 fpt_save_area = (void *) S390_lowcore.extended_save_area_addr;
269                 fpt_creg_save_area = fpt_save_area+128;
270 #endif
271                 /* Floating point control register */
272                 if (!mci->fc) {
273                         /*
274                          * Floating point control register can't be restored.
275                          * Task will be terminated.
276                          */
277                         asm volatile ("lfpc 0(%0)" : : "a" (&zero), "m" (zero));
278                         kill_task = 1;
279
280                 }
281                 else
282                         asm volatile (
283                                 "lfpc 0(%0)"
284                                 : : "a" (fpt_creg_save_area));
285
286                 asm volatile("ld  0,0(%0)\n"
287                              "ld  1,8(%0)\n"
288                              "ld  2,16(%0)\n"
289                              "ld  3,24(%0)\n"
290                              "ld  4,32(%0)\n"
291                              "ld  5,40(%0)\n"
292                              "ld  6,48(%0)\n"
293                              "ld  7,56(%0)\n"
294                              "ld  8,64(%0)\n"
295                              "ld  9,72(%0)\n"
296                              "ld 10,80(%0)\n"
297                              "ld 11,88(%0)\n"
298                              "ld 12,96(%0)\n"
299                              "ld 13,104(%0)\n"
300                              "ld 14,112(%0)\n"
301                              "ld 15,120(%0)\n"
302                              : : "a" (fpt_save_area));
303         }
304
305         /* Revalidate access registers */
306         asm volatile("lam 0,15,0(%0)"
307                      : : "a" (&S390_lowcore.access_regs_save_area));
308         if (!mci->ar)
309                 /*
310                  * Access registers have unknown contents.
311                  * Terminating task.
312                  */
313                 kill_task = 1;
314
315         /* Revalidate control registers */
316         if (!mci->cr)
317                 /*
318                  * Control registers have unknown contents.
319                  * Can't recover and therefore stopping machine.
320                  */
321                 s390_handle_damage("invalid control registers.");
322         else
323 #ifdef CONFIG_64BIT
324                 asm volatile("lctlg 0,15,0(%0)"
325                              : : "a" (&S390_lowcore.cregs_save_area));
326 #else
327                 asm volatile("lctl 0,15,0(%0)"
328                              : : "a" (&S390_lowcore.cregs_save_area));
329 #endif
330
331         /*
332          * We don't even try to revalidate the TOD register, since we simply
333          * can't write something sensible into that register.
334          */
335
336 #ifdef CONFIG_64BIT
337         /*
338          * See if we can revalidate the TOD programmable register with its
339          * old contents (should be zero) otherwise set it to zero.
340          */
341         if (!mci->pr)
342                 asm volatile("sr 0,0\n"
343                              "sckpf"
344                              : : : "0", "cc");
345         else
346                 asm volatile(
347                         "l 0,0(%0)\n"
348                         "sckpf"
349                         : : "a" (&S390_lowcore.tod_progreg_save_area) : "0", "cc");
350 #endif
351
352         /* Revalidate clock comparator register */
353         asm volatile ("stck 0(%1)\n"
354                       "sckc 0(%1)"
355                       : "=m" (tmpclock) : "a" (&(tmpclock)) : "cc", "memory");
356
357         /* Check if old PSW is valid */
358         if (!mci->wp)
359                 /*
360                  * Can't tell if we come from user or kernel mode
361                  * -> stopping machine.
362                  */
363                 s390_handle_damage("old psw invalid.");
364
365         if (!mci->ms || !mci->pm || !mci->ia)
366                 kill_task = 1;
367
368         return kill_task;
369 }
370
371 #define MAX_IPD_COUNT   29
372 #define MAX_IPD_TIME    (5 * 60 * USEC_PER_SEC) /* 5 minutes */
373
374 /*
375  * machine check handler.
376  */
377 void
378 s390_do_machine_check(struct pt_regs *regs)
379 {
380         static DEFINE_SPINLOCK(ipd_lock);
381         static unsigned long long last_ipd;
382         static int ipd_count;
383         unsigned long long tmp;
384         struct mci *mci;
385         struct mcck_struct *mcck;
386         int umode;
387
388         lockdep_off();
389
390         mci = (struct mci *) &S390_lowcore.mcck_interruption_code;
391         mcck = &__get_cpu_var(cpu_mcck);
392         umode = user_mode(regs);
393
394         if (mci->sd)
395                 /* System damage -> stopping machine */
396                 s390_handle_damage("received system damage machine check.");
397
398         if (mci->pd) {
399                 if (mci->b) {
400                         /* Processing backup -> verify if we can survive this */
401                         u64 z_mcic, o_mcic, t_mcic;
402 #ifdef CONFIG_64BIT
403                         z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29);
404                         o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
405                                   1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
406                                   1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 |
407                                   1ULL<<16);
408 #else
409                         z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<57 | 1ULL<<50 |
410                                   1ULL<<29);
411                         o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
412                                   1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
413                                   1ULL<<30 | 1ULL<<20 | 1ULL<<17 | 1ULL<<16);
414 #endif
415                         t_mcic = *(u64 *)mci;
416
417                         if (((t_mcic & z_mcic) != 0) ||
418                             ((t_mcic & o_mcic) != o_mcic)) {
419                                 s390_handle_damage("processing backup machine "
420                                                    "check with damage.");
421                         }
422
423                         /*
424                          * Nullifying exigent condition, therefore we might
425                          * retry this instruction.
426                          */
427
428                         spin_lock(&ipd_lock);
429
430                         tmp = get_clock();
431
432                         if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME)
433                                 ipd_count++;
434                         else
435                                 ipd_count = 1;
436
437                         last_ipd = tmp;
438
439                         if (ipd_count == MAX_IPD_COUNT)
440                                 s390_handle_damage("too many ipd retries.");
441
442                         spin_unlock(&ipd_lock);
443                 }
444                 else {
445                         /* Processing damage -> stopping machine */
446                         s390_handle_damage("received instruction processing "
447                                            "damage machine check.");
448                 }
449         }
450         if (s390_revalidate_registers(mci)) {
451                 if (umode) {
452                         /*
453                          * Couldn't restore all register contents while in
454                          * user mode -> mark task for termination.
455                          */
456                         mcck->kill_task = 1;
457                         mcck->mcck_code = *(unsigned long long *) mci;
458                         set_thread_flag(TIF_MCCK_PENDING);
459                 }
460                 else
461                         /*
462                          * Couldn't restore all register contents while in
463                          * kernel mode -> stopping machine.
464                          */
465                         s390_handle_damage("unable to revalidate registers.");
466         }
467
468         if (mci->se)
469                 /* Storage error uncorrected */
470                 s390_handle_damage("received storage error uncorrected "
471                                    "machine check.");
472
473         if (mci->ke)
474                 /* Storage key-error uncorrected */
475                 s390_handle_damage("received storage key-error uncorrected "
476                                    "machine check.");
477
478         if (mci->ds && mci->fa)
479                 /* Storage degradation */
480                 s390_handle_damage("received storage degradation machine "
481                                    "check.");
482
483         if (mci->cp) {
484                 /* Channel report word pending */
485                 mcck->channel_report = 1;
486                 set_thread_flag(TIF_MCCK_PENDING);
487         }
488
489         if (mci->w) {
490                 /* Warning pending */
491                 mcck->warning = 1;
492                 set_thread_flag(TIF_MCCK_PENDING);
493         }
494         lockdep_on();
495 }
496
497 /*
498  * s390_init_machine_check
499  *
500  * initialize machine check handling
501  */
502 static int
503 machine_check_init(void)
504 {
505         init_MUTEX_LOCKED(&m_sem);
506         ctl_clear_bit(14, 25);  /* disable external damage MCH */
507         ctl_set_bit(14, 27);    /* enable system recovery MCH */
508 #ifdef CONFIG_MACHCHK_WARNING
509         ctl_set_bit(14, 24);    /* enable warning MCH */
510 #endif
511         return 0;
512 }
513
514 /*
515  * Initialize the machine check handler really early to be able to
516  * catch all machine checks that happen during boot
517  */
518 arch_initcall(machine_check_init);
519
520 /*
521  * Machine checks for the channel subsystem must be enabled
522  * after the channel subsystem is initialized
523  */
524 static int __init
525 machine_check_crw_init (void)
526 {
527         kthread_run(s390_collect_crw_info, &m_sem, "kmcheck");
528         ctl_set_bit(14, 28);    /* enable channel report MCH */
529         return 0;
530 }
531
532 device_initcall (machine_check_crw_init);