fe75152a5084126043fbbbfdb0d955d3b4414afa
[linux-2.6.git] / drivers / s390 / s390mach.c
1 /*
2  *  drivers/s390/s390mach.c
3  *   S/390 machine check handler
4  *
5  *    Copyright IBM Corp. 2000,2008
6  *    Author(s): Ingo Adlung (adlung@de.ibm.com)
7  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
8  *               Cornelia Huck <cornelia.huck@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 "s390mach.h"
22
23 static struct semaphore m_sem;
24
25 static NORET_TYPE void
26 s390_handle_damage(char *msg)
27 {
28 #ifdef CONFIG_SMP
29         smp_send_stop();
30 #endif
31         disabled_wait((unsigned long) __builtin_return_address(0));
32         for(;;);
33 }
34
35 static crw_handler_t crw_handlers[NR_RSCS];
36
37 /**
38  * s390_register_crw_handler() - register a channel report word handler
39  * @rsc: reporting source code to handle
40  * @handler: handler to be registered
41  *
42  * Returns %0 on success and a negative error value otherwise.
43  */
44 int s390_register_crw_handler(int rsc, crw_handler_t handler)
45 {
46         if ((rsc < 0) || (rsc >= NR_RSCS))
47                 return -EINVAL;
48         if (!cmpxchg(&crw_handlers[rsc], NULL, handler))
49                 return 0;
50         return -EBUSY;
51 }
52
53 /**
54  * s390_unregister_crw_handler() - unregister a channel report word handler
55  * @rsc: reporting source code to handle
56  */
57 void s390_unregister_crw_handler(int rsc)
58 {
59         if ((rsc < 0) || (rsc >= NR_RSCS))
60                 return;
61         xchg(&crw_handlers[rsc], NULL);
62         synchronize_sched();
63 }
64
65 /*
66  * Retrieve CRWs and call function to handle event.
67  */
68 static int s390_collect_crw_info(void *param)
69 {
70         struct crw crw[2];
71         int ccode;
72         struct semaphore *sem;
73         unsigned int chain;
74         int ignore;
75
76         sem = (struct semaphore *)param;
77 repeat:
78         ignore = down_interruptible(sem);
79         chain = 0;
80         while (1) {
81                 if (unlikely(chain > 1)) {
82                         struct crw tmp_crw;
83
84                         printk(KERN_WARNING"%s: Code does not support more "
85                                "than two chained crws; please report to "
86                                "linux390@de.ibm.com!\n", __func__);
87                         ccode = stcrw(&tmp_crw);
88                         printk(KERN_WARNING"%s: crw reports slct=%d, oflw=%d, "
89                                "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
90                                __func__, tmp_crw.slct, tmp_crw.oflw,
91                                tmp_crw.chn, tmp_crw.rsc, tmp_crw.anc,
92                                tmp_crw.erc, tmp_crw.rsid);
93                         printk(KERN_WARNING"%s: This was crw number %x in the "
94                                "chain\n", __func__, chain);
95                         if (ccode != 0)
96                                 break;
97                         chain = tmp_crw.chn ? chain + 1 : 0;
98                         continue;
99                 }
100                 ccode = stcrw(&crw[chain]);
101                 if (ccode != 0)
102                         break;
103                 printk(KERN_DEBUG "crw_info : CRW reports slct=%d, oflw=%d, "
104                        "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
105                        crw[chain].slct, crw[chain].oflw, crw[chain].chn,
106                        crw[chain].rsc, crw[chain].anc, crw[chain].erc,
107                        crw[chain].rsid);
108                 /* Check for overflows. */
109                 if (crw[chain].oflw) {
110                         int i;
111
112                         pr_debug("%s: crw overflow detected!\n", __func__);
113                         for (i = 0; i < NR_RSCS; i++) {
114                                 if (crw_handlers[i])
115                                         crw_handlers[i](NULL, NULL, 1);
116                         }
117                         chain = 0;
118                         continue;
119                 }
120                 if (crw[0].chn && !chain) {
121                         chain++;
122                         continue;
123                 }
124                 if (crw_handlers[crw[chain].rsc])
125                         crw_handlers[crw[chain].rsc](&crw[0],
126                                                      chain ? &crw[1] : NULL,
127                                                      0);
128                 /* chain is always 0 or 1 here. */
129                 chain = crw[chain].chn ? chain + 1 : 0;
130         }
131         goto repeat;
132         return 0;
133 }
134
135 struct mcck_struct {
136         int kill_task;
137         int channel_report;
138         int warning;
139         unsigned long long mcck_code;
140 };
141
142 static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck);
143
144 /*
145  * Main machine check handler function. Will be called with interrupts enabled
146  * or disabled and machine checks enabled or disabled.
147  */
148 void
149 s390_handle_mcck(void)
150 {
151         unsigned long flags;
152         struct mcck_struct mcck;
153
154         /*
155          * Disable machine checks and get the current state of accumulated
156          * machine checks. Afterwards delete the old state and enable machine
157          * checks again.
158          */
159         local_irq_save(flags);
160         local_mcck_disable();
161         mcck = __get_cpu_var(cpu_mcck);
162         memset(&__get_cpu_var(cpu_mcck), 0, sizeof(struct mcck_struct));
163         clear_thread_flag(TIF_MCCK_PENDING);
164         local_mcck_enable();
165         local_irq_restore(flags);
166
167         if (mcck.channel_report)
168                 up(&m_sem);
169
170 #ifdef CONFIG_MACHCHK_WARNING
171 /*
172  * The warning may remain for a prolonged period on the bare iron.
173  * (actually till the machine is powered off, or until the problem is gone)
174  * So we just stop listening for the WARNING MCH and prevent continuously
175  * being interrupted.  One caveat is however, that we must do this per
176  * processor and cannot use the smp version of ctl_clear_bit().
177  * On VM we only get one interrupt per virtally presented machinecheck.
178  * Though one suffices, we may get one interrupt per (virtual) processor.
179  */
180         if (mcck.warning) {     /* WARNING pending ? */
181                 static int mchchk_wng_posted = 0;
182                 /*
183                  * Use single machine clear, as we cannot handle smp right now
184                  */
185                 __ctl_clear_bit(14, 24);        /* Disable WARNING MCH */
186                 if (xchg(&mchchk_wng_posted, 1) == 0)
187                         kill_cad_pid(SIGPWR, 1);
188         }
189 #endif
190
191         if (mcck.kill_task) {
192                 local_irq_enable();
193                 printk(KERN_EMERG "mcck: Terminating task because of machine "
194                        "malfunction (code 0x%016llx).\n", mcck.mcck_code);
195                 printk(KERN_EMERG "mcck: task: %s, pid: %d.\n",
196                        current->comm, current->pid);
197                 do_exit(SIGSEGV);
198         }
199 }
200 EXPORT_SYMBOL_GPL(s390_handle_mcck);
201
202 /*
203  * returns 0 if all registers could be validated
204  * returns 1 otherwise
205  */
206 static int
207 s390_revalidate_registers(struct mci *mci)
208 {
209         int kill_task;
210         u64 tmpclock;
211         u64 zero;
212         void *fpt_save_area, *fpt_creg_save_area;
213
214         kill_task = 0;
215         zero = 0;
216         /* General purpose registers */
217         if (!mci->gr)
218                 /*
219                  * General purpose registers couldn't be restored and have
220                  * unknown contents. Process needs to be terminated.
221                  */
222                 kill_task = 1;
223
224         /* Revalidate floating point registers */
225         if (!mci->fp)
226                 /*
227                  * Floating point registers can't be restored and
228                  * therefore the process needs to be terminated.
229                  */
230                 kill_task = 1;
231
232 #ifndef CONFIG_64BIT
233         asm volatile(
234                 "       ld      0,0(%0)\n"
235                 "       ld      2,8(%0)\n"
236                 "       ld      4,16(%0)\n"
237                 "       ld      6,24(%0)"
238                 : : "a" (&S390_lowcore.floating_pt_save_area));
239 #endif
240
241         if (MACHINE_HAS_IEEE) {
242 #ifdef CONFIG_64BIT
243                 fpt_save_area = &S390_lowcore.floating_pt_save_area;
244                 fpt_creg_save_area = &S390_lowcore.fpt_creg_save_area;
245 #else
246                 fpt_save_area = (void *) S390_lowcore.extended_save_area_addr;
247                 fpt_creg_save_area = fpt_save_area+128;
248 #endif
249                 /* Floating point control register */
250                 if (!mci->fc) {
251                         /*
252                          * Floating point control register can't be restored.
253                          * Task will be terminated.
254                          */
255                         asm volatile("lfpc 0(%0)" : : "a" (&zero), "m" (zero));
256                         kill_task = 1;
257
258                 } else
259                         asm volatile("lfpc 0(%0)" : : "a" (fpt_creg_save_area));
260
261                 asm volatile(
262                         "       ld      0,0(%0)\n"
263                         "       ld      1,8(%0)\n"
264                         "       ld      2,16(%0)\n"
265                         "       ld      3,24(%0)\n"
266                         "       ld      4,32(%0)\n"
267                         "       ld      5,40(%0)\n"
268                         "       ld      6,48(%0)\n"
269                         "       ld      7,56(%0)\n"
270                         "       ld      8,64(%0)\n"
271                         "       ld      9,72(%0)\n"
272                         "       ld      10,80(%0)\n"
273                         "       ld      11,88(%0)\n"
274                         "       ld      12,96(%0)\n"
275                         "       ld      13,104(%0)\n"
276                         "       ld      14,112(%0)\n"
277                         "       ld      15,120(%0)\n"
278                         : : "a" (fpt_save_area));
279         }
280
281         /* Revalidate access registers */
282         asm volatile(
283                 "       lam     0,15,0(%0)"
284                 : : "a" (&S390_lowcore.access_regs_save_area));
285         if (!mci->ar)
286                 /*
287                  * Access registers have unknown contents.
288                  * Terminating task.
289                  */
290                 kill_task = 1;
291
292         /* Revalidate control registers */
293         if (!mci->cr)
294                 /*
295                  * Control registers have unknown contents.
296                  * Can't recover and therefore stopping machine.
297                  */
298                 s390_handle_damage("invalid control registers.");
299         else
300 #ifdef CONFIG_64BIT
301                 asm volatile(
302                         "       lctlg   0,15,0(%0)"
303                         : : "a" (&S390_lowcore.cregs_save_area));
304 #else
305                 asm volatile(
306                         "       lctl    0,15,0(%0)"
307                         : : "a" (&S390_lowcore.cregs_save_area));
308 #endif
309
310         /*
311          * We don't even try to revalidate the TOD register, since we simply
312          * can't write something sensible into that register.
313          */
314
315 #ifdef CONFIG_64BIT
316         /*
317          * See if we can revalidate the TOD programmable register with its
318          * old contents (should be zero) otherwise set it to zero.
319          */
320         if (!mci->pr)
321                 asm volatile(
322                         "       sr      0,0\n"
323                         "       sckpf"
324                         : : : "0", "cc");
325         else
326                 asm volatile(
327                         "       l       0,0(%0)\n"
328                         "       sckpf"
329                         : : "a" (&S390_lowcore.tod_progreg_save_area)
330                         : "0", "cc");
331 #endif
332
333         /* Revalidate clock comparator register */
334         asm volatile(
335                 "       stck    0(%1)\n"
336                 "       sckc    0(%1)"
337                 : "=m" (tmpclock) : "a" (&(tmpclock)) : "cc", "memory");
338
339         /* Check if old PSW is valid */
340         if (!mci->wp)
341                 /*
342                  * Can't tell if we come from user or kernel mode
343                  * -> stopping machine.
344                  */
345                 s390_handle_damage("old psw invalid.");
346
347         if (!mci->ms || !mci->pm || !mci->ia)
348                 kill_task = 1;
349
350         return kill_task;
351 }
352
353 #define MAX_IPD_COUNT   29
354 #define MAX_IPD_TIME    (5 * 60 * USEC_PER_SEC) /* 5 minutes */
355
356 /*
357  * machine check handler.
358  */
359 void
360 s390_do_machine_check(struct pt_regs *regs)
361 {
362         static DEFINE_SPINLOCK(ipd_lock);
363         static unsigned long long last_ipd;
364         static int ipd_count;
365         unsigned long long tmp;
366         struct mci *mci;
367         struct mcck_struct *mcck;
368         int umode;
369
370         lockdep_off();
371
372         mci = (struct mci *) &S390_lowcore.mcck_interruption_code;
373         mcck = &__get_cpu_var(cpu_mcck);
374         umode = user_mode(regs);
375
376         if (mci->sd)
377                 /* System damage -> stopping machine */
378                 s390_handle_damage("received system damage machine check.");
379
380         if (mci->pd) {
381                 if (mci->b) {
382                         /* Processing backup -> verify if we can survive this */
383                         u64 z_mcic, o_mcic, t_mcic;
384 #ifdef CONFIG_64BIT
385                         z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29);
386                         o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
387                                   1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
388                                   1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 |
389                                   1ULL<<16);
390 #else
391                         z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<57 | 1ULL<<50 |
392                                   1ULL<<29);
393                         o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
394                                   1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
395                                   1ULL<<30 | 1ULL<<20 | 1ULL<<17 | 1ULL<<16);
396 #endif
397                         t_mcic = *(u64 *)mci;
398
399                         if (((t_mcic & z_mcic) != 0) ||
400                             ((t_mcic & o_mcic) != o_mcic)) {
401                                 s390_handle_damage("processing backup machine "
402                                                    "check with damage.");
403                         }
404
405                         /*
406                          * Nullifying exigent condition, therefore we might
407                          * retry this instruction.
408                          */
409
410                         spin_lock(&ipd_lock);
411
412                         tmp = get_clock();
413
414                         if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME)
415                                 ipd_count++;
416                         else
417                                 ipd_count = 1;
418
419                         last_ipd = tmp;
420
421                         if (ipd_count == MAX_IPD_COUNT)
422                                 s390_handle_damage("too many ipd retries.");
423
424                         spin_unlock(&ipd_lock);
425                 }
426                 else {
427                         /* Processing damage -> stopping machine */
428                         s390_handle_damage("received instruction processing "
429                                            "damage machine check.");
430                 }
431         }
432         if (s390_revalidate_registers(mci)) {
433                 if (umode) {
434                         /*
435                          * Couldn't restore all register contents while in
436                          * user mode -> mark task for termination.
437                          */
438                         mcck->kill_task = 1;
439                         mcck->mcck_code = *(unsigned long long *) mci;
440                         set_thread_flag(TIF_MCCK_PENDING);
441                 }
442                 else
443                         /*
444                          * Couldn't restore all register contents while in
445                          * kernel mode -> stopping machine.
446                          */
447                         s390_handle_damage("unable to revalidate registers.");
448         }
449
450         if (mci->cd) {
451                 /* Timing facility damage */
452                 s390_handle_damage("TOD clock damaged");
453         }
454
455         if (mci->ed && mci->ec) {
456                 /* External damage */
457                 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SYNC))
458                         etr_sync_check();
459                 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SWITCH))
460                         etr_switch_to_local();
461         }
462
463         if (mci->se)
464                 /* Storage error uncorrected */
465                 s390_handle_damage("received storage error uncorrected "
466                                    "machine check.");
467
468         if (mci->ke)
469                 /* Storage key-error uncorrected */
470                 s390_handle_damage("received storage key-error uncorrected "
471                                    "machine check.");
472
473         if (mci->ds && mci->fa)
474                 /* Storage degradation */
475                 s390_handle_damage("received storage degradation machine "
476                                    "check.");
477
478         if (mci->cp) {
479                 /* Channel report word pending */
480                 mcck->channel_report = 1;
481                 set_thread_flag(TIF_MCCK_PENDING);
482         }
483
484         if (mci->w) {
485                 /* Warning pending */
486                 mcck->warning = 1;
487                 set_thread_flag(TIF_MCCK_PENDING);
488         }
489         lockdep_on();
490 }
491
492 /*
493  * s390_init_machine_check
494  *
495  * initialize machine check handling
496  */
497 static int
498 machine_check_init(void)
499 {
500         init_MUTEX_LOCKED(&m_sem);
501         ctl_set_bit(14, 25);    /* enable external damage MCH */
502         ctl_set_bit(14, 27);    /* enable system recovery MCH */
503 #ifdef CONFIG_MACHCHK_WARNING
504         ctl_set_bit(14, 24);    /* enable warning MCH */
505 #endif
506         return 0;
507 }
508
509 /*
510  * Initialize the machine check handler really early to be able to
511  * catch all machine checks that happen during boot
512  */
513 arch_initcall(machine_check_init);
514
515 /*
516  * Machine checks for the channel subsystem must be enabled
517  * after the channel subsystem is initialized
518  */
519 static int __init
520 machine_check_crw_init (void)
521 {
522         struct task_struct *task;
523
524         task = kthread_run(s390_collect_crw_info, &m_sem, "kmcheck");
525         if (IS_ERR(task))
526                 return PTR_ERR(task);
527         ctl_set_bit(14, 28);    /* enable channel report MCH */
528         return 0;
529 }
530
531 device_initcall (machine_check_crw_init);