Merge branch 'upstream-linus' of master.kernel.org:/pub/scm/linux/kernel/git/jgarzik...
[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 "s390mach.h"
25
26 static struct semaphore m_sem;
27
28 static NORET_TYPE void
29 s390_handle_damage(char *msg)
30 {
31 #ifdef CONFIG_SMP
32         smp_send_stop();
33 #endif
34         disabled_wait((unsigned long) __builtin_return_address(0));
35         for(;;);
36 }
37
38 /*
39  * Retrieve CRWs and call function to handle event.
40  *
41  * Note : we currently process CRWs for io and chsc subchannels only
42  */
43 static int
44 s390_collect_crw_info(void *param)
45 {
46         struct crw crw[2];
47         int ccode, ret, slow;
48         struct semaphore *sem;
49         unsigned int chain;
50
51         sem = (struct semaphore *)param;
52 repeat:
53         down_interruptible(sem);
54         slow = 0;
55         chain = 0;
56         while (1) {
57                 if (unlikely(chain > 1)) {
58                         struct crw tmp_crw;
59
60                         printk(KERN_WARNING"%s: Code does not support more "
61                                "than two chained crws; please report to "
62                                "linux390@de.ibm.com!\n", __FUNCTION__);
63                         ccode = stcrw(&tmp_crw);
64                         printk(KERN_WARNING"%s: crw reports slct=%d, oflw=%d, "
65                                "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
66                                __FUNCTION__, tmp_crw.slct, tmp_crw.oflw,
67                                tmp_crw.chn, tmp_crw.rsc, tmp_crw.anc,
68                                tmp_crw.erc, tmp_crw.rsid);
69                         printk(KERN_WARNING"%s: This was crw number %x in the "
70                                "chain\n", __FUNCTION__, chain);
71                         if (ccode != 0)
72                                 break;
73                         chain = tmp_crw.chn ? chain + 1 : 0;
74                         continue;
75                 }
76                 ccode = stcrw(&crw[chain]);
77                 if (ccode != 0)
78                         break;
79                 printk(KERN_DEBUG "crw_info : CRW reports slct=%d, oflw=%d, "
80                        "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
81                        crw[chain].slct, crw[chain].oflw, crw[chain].chn,
82                        crw[chain].rsc, crw[chain].anc, crw[chain].erc,
83                        crw[chain].rsid);
84                 /* Check for overflows. */
85                 if (crw[chain].oflw) {
86                         pr_debug("%s: crw overflow detected!\n", __FUNCTION__);
87                         css_reiterate_subchannels();
88                         chain = 0;
89                         slow = 1;
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                         ret = css_process_crw (crw[0].rsid,
98                                                chain ? crw[1].rsid : 0);
99                         if (ret == -EAGAIN)
100                                 slow = 1;
101                         break;
102                 case CRW_RSC_MONITOR:
103                         pr_debug("source is monitoring facility\n");
104                         break;
105                 case CRW_RSC_CPATH:
106                         pr_debug("source is channel path %02X\n", crw[0].rsid);
107                         /*
108                          * Check for solicited machine checks. These are
109                          * created by reset channel path and need not be
110                          * reported to the common I/O layer.
111                          */
112                         if (crw[chain].slct) {
113                                 pr_debug("solicited machine check for "
114                                          "channel path %02X\n", crw[0].rsid);
115                                 break;
116                         }
117                         switch (crw[0].erc) {
118                         case CRW_ERC_IPARM: /* Path has come. */
119                                 ret = chp_process_crw(crw[0].rsid, 1);
120                                 break;
121                         case CRW_ERC_PERRI: /* Path has gone. */
122                         case CRW_ERC_PERRN:
123                                 ret = chp_process_crw(crw[0].rsid, 0);
124                                 break;
125                         default:
126                                 pr_debug("Don't know how to handle erc=%x\n",
127                                          crw[0].erc);
128                                 ret = 0;
129                         }
130                         if (ret == -EAGAIN)
131                                 slow = 1;
132                         break;
133                 case CRW_RSC_CONFIG:
134                         pr_debug("source is configuration-alert facility\n");
135                         break;
136                 case CRW_RSC_CSS:
137                         pr_debug("source is channel subsystem\n");
138                         ret = chsc_process_crw();
139                         if (ret == -EAGAIN)
140                                 slow = 1;
141                         break;
142                 default:
143                         pr_debug("unknown source\n");
144                         break;
145                 }
146                 /* chain is always 0 or 1 here. */
147                 chain = crw[chain].chn ? chain + 1 : 0;
148         }
149         if (slow)
150                 queue_work(slow_path_wq, &slow_path_work);
151         goto repeat;
152         return 0;
153 }
154
155 struct mcck_struct {
156         int kill_task;
157         int channel_report;
158         int warning;
159         unsigned long long mcck_code;
160 };
161
162 static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck);
163
164 /*
165  * Main machine check handler function. Will be called with interrupts enabled
166  * or disabled and machine checks enabled or disabled.
167  */
168 void
169 s390_handle_mcck(void)
170 {
171         unsigned long flags;
172         struct mcck_struct mcck;
173
174         /*
175          * Disable machine checks and get the current state of accumulated
176          * machine checks. Afterwards delete the old state and enable machine
177          * checks again.
178          */
179         local_irq_save(flags);
180         local_mcck_disable();
181         mcck = __get_cpu_var(cpu_mcck);
182         memset(&__get_cpu_var(cpu_mcck), 0, sizeof(struct mcck_struct));
183         clear_thread_flag(TIF_MCCK_PENDING);
184         local_mcck_enable();
185         local_irq_restore(flags);
186
187         if (mcck.channel_report)
188                 up(&m_sem);
189
190 #ifdef CONFIG_MACHCHK_WARNING
191 /*
192  * The warning may remain for a prolonged period on the bare iron.
193  * (actually till the machine is powered off, or until the problem is gone)
194  * So we just stop listening for the WARNING MCH and prevent continuously
195  * being interrupted.  One caveat is however, that we must do this per
196  * processor and cannot use the smp version of ctl_clear_bit().
197  * On VM we only get one interrupt per virtally presented machinecheck.
198  * Though one suffices, we may get one interrupt per (virtual) processor.
199  */
200         if (mcck.warning) {     /* WARNING pending ? */
201                 static int mchchk_wng_posted = 0;
202                 /*
203                  * Use single machine clear, as we cannot handle smp right now
204                  */
205                 __ctl_clear_bit(14, 24);        /* Disable WARNING MCH */
206                 if (xchg(&mchchk_wng_posted, 1) == 0)
207                         kill_cad_pid(SIGPWR, 1);
208         }
209 #endif
210
211         if (mcck.kill_task) {
212                 local_irq_enable();
213                 printk(KERN_EMERG "mcck: Terminating task because of machine "
214                        "malfunction (code 0x%016llx).\n", mcck.mcck_code);
215                 printk(KERN_EMERG "mcck: task: %s, pid: %d.\n",
216                        current->comm, current->pid);
217                 do_exit(SIGSEGV);
218         }
219 }
220
221 /*
222  * returns 0 if all registers could be validated
223  * returns 1 otherwise
224  */
225 static int
226 s390_revalidate_registers(struct mci *mci)
227 {
228         int kill_task;
229         u64 tmpclock;
230         u64 zero;
231         void *fpt_save_area, *fpt_creg_save_area;
232
233         kill_task = 0;
234         zero = 0;
235         /* General purpose registers */
236         if (!mci->gr)
237                 /*
238                  * General purpose registers couldn't be restored and have
239                  * unknown contents. Process needs to be terminated.
240                  */
241                 kill_task = 1;
242
243         /* Revalidate floating point registers */
244         if (!mci->fp)
245                 /*
246                  * Floating point registers can't be restored and
247                  * therefore the process needs to be terminated.
248                  */
249                 kill_task = 1;
250
251 #ifndef CONFIG_64BIT
252         asm volatile(
253                 "       ld      0,0(%0)\n"
254                 "       ld      2,8(%0)\n"
255                 "       ld      4,16(%0)\n"
256                 "       ld      6,24(%0)"
257                 : : "a" (&S390_lowcore.floating_pt_save_area));
258 #endif
259
260         if (MACHINE_HAS_IEEE) {
261 #ifdef CONFIG_64BIT
262                 fpt_save_area = &S390_lowcore.floating_pt_save_area;
263                 fpt_creg_save_area = &S390_lowcore.fpt_creg_save_area;
264 #else
265                 fpt_save_area = (void *) S390_lowcore.extended_save_area_addr;
266                 fpt_creg_save_area = fpt_save_area+128;
267 #endif
268                 /* Floating point control register */
269                 if (!mci->fc) {
270                         /*
271                          * Floating point control register can't be restored.
272                          * Task will be terminated.
273                          */
274                         asm volatile("lfpc 0(%0)" : : "a" (&zero), "m" (zero));
275                         kill_task = 1;
276
277                 } else
278                         asm volatile("lfpc 0(%0)" : : "a" (fpt_creg_save_area));
279
280                 asm volatile(
281                         "       ld      0,0(%0)\n"
282                         "       ld      1,8(%0)\n"
283                         "       ld      2,16(%0)\n"
284                         "       ld      3,24(%0)\n"
285                         "       ld      4,32(%0)\n"
286                         "       ld      5,40(%0)\n"
287                         "       ld      6,48(%0)\n"
288                         "       ld      7,56(%0)\n"
289                         "       ld      8,64(%0)\n"
290                         "       ld      9,72(%0)\n"
291                         "       ld      10,80(%0)\n"
292                         "       ld      11,88(%0)\n"
293                         "       ld      12,96(%0)\n"
294                         "       ld      13,104(%0)\n"
295                         "       ld      14,112(%0)\n"
296                         "       ld      15,120(%0)\n"
297                         : : "a" (fpt_save_area));
298         }
299
300         /* Revalidate access registers */
301         asm volatile(
302                 "       lam     0,15,0(%0)"
303                 : : "a" (&S390_lowcore.access_regs_save_area));
304         if (!mci->ar)
305                 /*
306                  * Access registers have unknown contents.
307                  * Terminating task.
308                  */
309                 kill_task = 1;
310
311         /* Revalidate control registers */
312         if (!mci->cr)
313                 /*
314                  * Control registers have unknown contents.
315                  * Can't recover and therefore stopping machine.
316                  */
317                 s390_handle_damage("invalid control registers.");
318         else
319 #ifdef CONFIG_64BIT
320                 asm volatile(
321                         "       lctlg   0,15,0(%0)"
322                         : : "a" (&S390_lowcore.cregs_save_area));
323 #else
324                 asm volatile(
325                         "       lctl    0,15,0(%0)"
326                         : : "a" (&S390_lowcore.cregs_save_area));
327 #endif
328
329         /*
330          * We don't even try to revalidate the TOD register, since we simply
331          * can't write something sensible into that register.
332          */
333
334 #ifdef CONFIG_64BIT
335         /*
336          * See if we can revalidate the TOD programmable register with its
337          * old contents (should be zero) otherwise set it to zero.
338          */
339         if (!mci->pr)
340                 asm volatile(
341                         "       sr      0,0\n"
342                         "       sckpf"
343                         : : : "0", "cc");
344         else
345                 asm volatile(
346                         "       l       0,0(%0)\n"
347                         "       sckpf"
348                         : : "a" (&S390_lowcore.tod_progreg_save_area)
349                         : "0", "cc");
350 #endif
351
352         /* Revalidate clock comparator register */
353         asm volatile(
354                 "       stck    0(%1)\n"
355                 "       sckc    0(%1)"
356                 : "=m" (tmpclock) : "a" (&(tmpclock)) : "cc", "memory");
357
358         /* Check if old PSW is valid */
359         if (!mci->wp)
360                 /*
361                  * Can't tell if we come from user or kernel mode
362                  * -> stopping machine.
363                  */
364                 s390_handle_damage("old psw invalid.");
365
366         if (!mci->ms || !mci->pm || !mci->ia)
367                 kill_task = 1;
368
369         return kill_task;
370 }
371
372 #define MAX_IPD_COUNT   29
373 #define MAX_IPD_TIME    (5 * 60 * USEC_PER_SEC) /* 5 minutes */
374
375 /*
376  * machine check handler.
377  */
378 void
379 s390_do_machine_check(struct pt_regs *regs)
380 {
381         static DEFINE_SPINLOCK(ipd_lock);
382         static unsigned long long last_ipd;
383         static int ipd_count;
384         unsigned long long tmp;
385         struct mci *mci;
386         struct mcck_struct *mcck;
387         int umode;
388
389         lockdep_off();
390
391         mci = (struct mci *) &S390_lowcore.mcck_interruption_code;
392         mcck = &__get_cpu_var(cpu_mcck);
393         umode = user_mode(regs);
394
395         if (mci->sd)
396                 /* System damage -> stopping machine */
397                 s390_handle_damage("received system damage machine check.");
398
399         if (mci->pd) {
400                 if (mci->b) {
401                         /* Processing backup -> verify if we can survive this */
402                         u64 z_mcic, o_mcic, t_mcic;
403 #ifdef CONFIG_64BIT
404                         z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29);
405                         o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
406                                   1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
407                                   1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 |
408                                   1ULL<<16);
409 #else
410                         z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<57 | 1ULL<<50 |
411                                   1ULL<<29);
412                         o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
413                                   1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
414                                   1ULL<<30 | 1ULL<<20 | 1ULL<<17 | 1ULL<<16);
415 #endif
416                         t_mcic = *(u64 *)mci;
417
418                         if (((t_mcic & z_mcic) != 0) ||
419                             ((t_mcic & o_mcic) != o_mcic)) {
420                                 s390_handle_damage("processing backup machine "
421                                                    "check with damage.");
422                         }
423
424                         /*
425                          * Nullifying exigent condition, therefore we might
426                          * retry this instruction.
427                          */
428
429                         spin_lock(&ipd_lock);
430
431                         tmp = get_clock();
432
433                         if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME)
434                                 ipd_count++;
435                         else
436                                 ipd_count = 1;
437
438                         last_ipd = tmp;
439
440                         if (ipd_count == MAX_IPD_COUNT)
441                                 s390_handle_damage("too many ipd retries.");
442
443                         spin_unlock(&ipd_lock);
444                 }
445                 else {
446                         /* Processing damage -> stopping machine */
447                         s390_handle_damage("received instruction processing "
448                                            "damage machine check.");
449                 }
450         }
451         if (s390_revalidate_registers(mci)) {
452                 if (umode) {
453                         /*
454                          * Couldn't restore all register contents while in
455                          * user mode -> mark task for termination.
456                          */
457                         mcck->kill_task = 1;
458                         mcck->mcck_code = *(unsigned long long *) mci;
459                         set_thread_flag(TIF_MCCK_PENDING);
460                 }
461                 else
462                         /*
463                          * Couldn't restore all register contents while in
464                          * kernel mode -> stopping machine.
465                          */
466                         s390_handle_damage("unable to revalidate registers.");
467         }
468
469         if (mci->cd) {
470                 /* Timing facility damage */
471                 s390_handle_damage("TOD clock damaged");
472         }
473
474         if (mci->ed && mci->ec) {
475                 /* External damage */
476                 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SYNC))
477                         etr_sync_check();
478                 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SWITCH))
479                         etr_switch_to_local();
480         }
481
482         if (mci->se)
483                 /* Storage error uncorrected */
484                 s390_handle_damage("received storage error uncorrected "
485                                    "machine check.");
486
487         if (mci->ke)
488                 /* Storage key-error uncorrected */
489                 s390_handle_damage("received storage key-error uncorrected "
490                                    "machine check.");
491
492         if (mci->ds && mci->fa)
493                 /* Storage degradation */
494                 s390_handle_damage("received storage degradation machine "
495                                    "check.");
496
497         if (mci->cp) {
498                 /* Channel report word pending */
499                 mcck->channel_report = 1;
500                 set_thread_flag(TIF_MCCK_PENDING);
501         }
502
503         if (mci->w) {
504                 /* Warning pending */
505                 mcck->warning = 1;
506                 set_thread_flag(TIF_MCCK_PENDING);
507         }
508         lockdep_on();
509 }
510
511 /*
512  * s390_init_machine_check
513  *
514  * initialize machine check handling
515  */
516 static int
517 machine_check_init(void)
518 {
519         init_MUTEX_LOCKED(&m_sem);
520         ctl_set_bit(14, 25);    /* enable external damage MCH */
521         ctl_set_bit(14, 27);    /* enable system recovery MCH */
522 #ifdef CONFIG_MACHCHK_WARNING
523         ctl_set_bit(14, 24);    /* enable warning MCH */
524 #endif
525         return 0;
526 }
527
528 /*
529  * Initialize the machine check handler really early to be able to
530  * catch all machine checks that happen during boot
531  */
532 arch_initcall(machine_check_init);
533
534 /*
535  * Machine checks for the channel subsystem must be enabled
536  * after the channel subsystem is initialized
537  */
538 static int __init
539 machine_check_crw_init (void)
540 {
541         struct task_struct *task;
542
543         task = kthread_run(s390_collect_crw_info, &m_sem, "kmcheck");
544         if (IS_ERR(task))
545                 return PTR_ERR(task);
546         ctl_set_bit(14, 28);    /* enable channel report MCH */
547         return 0;
548 }
549
550 device_initcall (machine_check_crw_init);