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V4L/DVB (6715): ivtv: Remove unnecessary register update
[linux-2.6/verdex.git] / drivers / s390 / s390mach.c
blob644a06eba828d7d48e386fdfdfe64424b36f13db
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
52 sem = (struct semaphore *)param;
53 repeat:
54 down_interruptible(sem);
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_schedule_eval_all();
88 chain = 0;
89 continue;
90 }
91 switch (crw[chain].rsc) {
92 case CRW_RSC_SCH:
93 if (crw[0].chn && !chain)
94 break;
95 pr_debug("source is subchannel %04X\n", crw[0].rsid);
96 css_process_crw(crw[0].rsid, chain ? crw[1].rsid : 0);
97 break;
98 case CRW_RSC_MONITOR:
99 pr_debug("source is monitoring facility\n");
100 break;
101 case CRW_RSC_CPATH:
102 pr_debug("source is channel path %02X\n", crw[0].rsid);
103 /*
104 * Check for solicited machine checks. These are
105 * created by reset channel path and need not be
106 * reported to the common I/O layer.
107 */
108 if (crw[chain].slct) {
109 pr_debug("solicited machine check for "
110 "channel path %02X\n", crw[0].rsid);
111 break;
112 }
113 switch (crw[0].erc) {
114 case CRW_ERC_IPARM: /* Path has come. */
115 chp_process_crw(crw[0].rsid, 1);
116 break;
117 case CRW_ERC_PERRI: /* Path has gone. */
118 case CRW_ERC_PERRN:
119 chp_process_crw(crw[0].rsid, 0);
120 break;
121 default:
122 pr_debug("Don't know how to handle erc=%x\n",
123 crw[0].erc);
124 }
125 break;
126 case CRW_RSC_CONFIG:
127 pr_debug("source is configuration-alert facility\n");
128 break;
129 case CRW_RSC_CSS:
130 pr_debug("source is channel subsystem\n");
131 chsc_process_crw();
132 break;
133 default:
134 pr_debug("unknown source\n");
135 break;
136 }
137 /* chain is always 0 or 1 here. */
138 chain = crw[chain].chn ? chain + 1 : 0;
139 }
140 goto repeat;
141 return 0;
142 }
143
144 struct mcck_struct {
145 int kill_task;
146 int channel_report;
147 int warning;
148 unsigned long long mcck_code;
149 };
150
151 static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck);
152
153 /*
154 * Main machine check handler function. Will be called with interrupts enabled
155 * or disabled and machine checks enabled or disabled.
156 */
157 void
158 s390_handle_mcck(void)
159 {
160 unsigned long flags;
161 struct mcck_struct mcck;
162
163 /*
164 * Disable machine checks and get the current state of accumulated
165 * machine checks. Afterwards delete the old state and enable machine
166 * checks again.
167 */
168 local_irq_save(flags);
169 local_mcck_disable();
170 mcck = __get_cpu_var(cpu_mcck);
171 memset(&__get_cpu_var(cpu_mcck), 0, sizeof(struct mcck_struct));
172 clear_thread_flag(TIF_MCCK_PENDING);
173 local_mcck_enable();
174 local_irq_restore(flags);
175
176 if (mcck.channel_report)
177 up(&m_sem);
178
179 #ifdef CONFIG_MACHCHK_WARNING
180 /*
181 * The warning may remain for a prolonged period on the bare iron.
182 * (actually till the machine is powered off, or until the problem is gone)
183 * So we just stop listening for the WARNING MCH and prevent continuously
184 * being interrupted. One caveat is however, that we must do this per
185 * processor and cannot use the smp version of ctl_clear_bit().
186 * On VM we only get one interrupt per virtally presented machinecheck.
187 * Though one suffices, we may get one interrupt per (virtual) processor.
188 */
189 if (mcck.warning) { /* WARNING pending ? */
190 static int mchchk_wng_posted = 0;
191 /*
192 * Use single machine clear, as we cannot handle smp right now
193 */
194 __ctl_clear_bit(14, 24); /* Disable WARNING MCH */
195 if (xchg(&mchchk_wng_posted, 1) == 0)
196 kill_cad_pid(SIGPWR, 1);
197 }
198 #endif
199
200 if (mcck.kill_task) {
201 local_irq_enable();
202 printk(KERN_EMERG "mcck: Terminating task because of machine "
203 "malfunction (code 0x%016llx).\n", mcck.mcck_code);
204 printk(KERN_EMERG "mcck: task: %s, pid: %d.\n",
205 current->comm, current->pid);
206 do_exit(SIGSEGV);
207 }
208 }
209
210 /*
211 * returns 0 if all registers could be validated
212 * returns 1 otherwise
213 */
214 static int
215 s390_revalidate_registers(struct mci *mci)
216 {
217 int kill_task;
218 u64 tmpclock;
219 u64 zero;
220 void *fpt_save_area, *fpt_creg_save_area;
221
222 kill_task = 0;
223 zero = 0;
224 /* General purpose registers */
225 if (!mci->gr)
226 /*
227 * General purpose registers couldn't be restored and have
228 * unknown contents. Process needs to be terminated.
229 */
230 kill_task = 1;
231
232 /* Revalidate floating point registers */
233 if (!mci->fp)
234 /*
235 * Floating point registers can't be restored and
236 * therefore the process needs to be terminated.
237 */
238 kill_task = 1;
239
240 #ifndef CONFIG_64BIT
241 asm volatile(
242 " ld 0,0(%0)\n"
243 " ld 2,8(%0)\n"
244 " ld 4,16(%0)\n"
245 " ld 6,24(%0)"
246 : : "a" (&S390_lowcore.floating_pt_save_area));
247 #endif
248
249 if (MACHINE_HAS_IEEE) {
250 #ifdef CONFIG_64BIT
251 fpt_save_area = &S390_lowcore.floating_pt_save_area;
252 fpt_creg_save_area = &S390_lowcore.fpt_creg_save_area;
253 #else
254 fpt_save_area = (void *) S390_lowcore.extended_save_area_addr;
255 fpt_creg_save_area = fpt_save_area+128;
256 #endif
257 /* Floating point control register */
258 if (!mci->fc) {
259 /*
260 * Floating point control register can't be restored.
261 * Task will be terminated.
262 */
263 asm volatile("lfpc 0(%0)" : : "a" (&zero), "m" (zero));
264 kill_task = 1;
265
266 } else
267 asm volatile("lfpc 0(%0)" : : "a" (fpt_creg_save_area));
268
269 asm volatile(
270 " ld 0,0(%0)\n"
271 " ld 1,8(%0)\n"
272 " ld 2,16(%0)\n"
273 " ld 3,24(%0)\n"
274 " ld 4,32(%0)\n"
275 " ld 5,40(%0)\n"
276 " ld 6,48(%0)\n"
277 " ld 7,56(%0)\n"
278 " ld 8,64(%0)\n"
279 " ld 9,72(%0)\n"
280 " ld 10,80(%0)\n"
281 " ld 11,88(%0)\n"
282 " ld 12,96(%0)\n"
283 " ld 13,104(%0)\n"
284 " ld 14,112(%0)\n"
285 " ld 15,120(%0)\n"
286 : : "a" (fpt_save_area));
287 }
288
289 /* Revalidate access registers */
290 asm volatile(
291 " lam 0,15,0(%0)"
292 : : "a" (&S390_lowcore.access_regs_save_area));
293 if (!mci->ar)
294 /*
295 * Access registers have unknown contents.
296 * Terminating task.
297 */
298 kill_task = 1;
299
300 /* Revalidate control registers */
301 if (!mci->cr)
302 /*
303 * Control registers have unknown contents.
304 * Can't recover and therefore stopping machine.
305 */
306 s390_handle_damage("invalid control registers.");
307 else
308 #ifdef CONFIG_64BIT
309 asm volatile(
310 " lctlg 0,15,0(%0)"
311 : : "a" (&S390_lowcore.cregs_save_area));
312 #else
313 asm volatile(
314 " lctl 0,15,0(%0)"
315 : : "a" (&S390_lowcore.cregs_save_area));
316 #endif
317
318 /*
319 * We don't even try to revalidate the TOD register, since we simply
320 * can't write something sensible into that register.
321 */
322
323 #ifdef CONFIG_64BIT
324 /*
325 * See if we can revalidate the TOD programmable register with its
326 * old contents (should be zero) otherwise set it to zero.
327 */
328 if (!mci->pr)
329 asm volatile(
330 " sr 0,0\n"
331 " sckpf"
332 : : : "0", "cc");
333 else
334 asm volatile(
335 " l 0,0(%0)\n"
336 " sckpf"
337 : : "a" (&S390_lowcore.tod_progreg_save_area)
338 : "0", "cc");
339 #endif
340
341 /* Revalidate clock comparator register */
342 asm volatile(
343 " stck 0(%1)\n"
344 " sckc 0(%1)"
345 : "=m" (tmpclock) : "a" (&(tmpclock)) : "cc", "memory");
346
347 /* Check if old PSW is valid */
348 if (!mci->wp)
349 /*
350 * Can't tell if we come from user or kernel mode
351 * -> stopping machine.
352 */
353 s390_handle_damage("old psw invalid.");
354
355 if (!mci->ms || !mci->pm || !mci->ia)
356 kill_task = 1;
357
358 return kill_task;
359 }
360
361 #define MAX_IPD_COUNT 29
362 #define MAX_IPD_TIME (5 * 60 * USEC_PER_SEC) /* 5 minutes */
363
364 /*
365 * machine check handler.
366 */
367 void
368 s390_do_machine_check(struct pt_regs *regs)
369 {
370 static DEFINE_SPINLOCK(ipd_lock);
371 static unsigned long long last_ipd;
372 static int ipd_count;
373 unsigned long long tmp;
374 struct mci *mci;
375 struct mcck_struct *mcck;
376 int umode;
377
378 lockdep_off();
379
380 mci = (struct mci *) &S390_lowcore.mcck_interruption_code;
381 mcck = &__get_cpu_var(cpu_mcck);
382 umode = user_mode(regs);
383
384 if (mci->sd)
385 /* System damage -> stopping machine */
386 s390_handle_damage("received system damage machine check.");
387
388 if (mci->pd) {
389 if (mci->b) {
390 /* Processing backup -> verify if we can survive this */
391 u64 z_mcic, o_mcic, t_mcic;
392 #ifdef CONFIG_64BIT
393 z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29);
394 o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
395 1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
396 1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 |
397 1ULL<<16);
398 #else
399 z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<57 | 1ULL<<50 |
400 1ULL<<29);
401 o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
402 1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
403 1ULL<<30 | 1ULL<<20 | 1ULL<<17 | 1ULL<<16);
404 #endif
405 t_mcic = *(u64 *)mci;
406
407 if (((t_mcic & z_mcic) != 0) ||
408 ((t_mcic & o_mcic) != o_mcic)) {
409 s390_handle_damage("processing backup machine "
410 "check with damage.");
411 }
412
413 /*
414 * Nullifying exigent condition, therefore we might
415 * retry this instruction.
416 */
417
418 spin_lock(&ipd_lock);
419
420 tmp = get_clock();
421
422 if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME)
423 ipd_count++;
424 else
425 ipd_count = 1;
426
427 last_ipd = tmp;
428
429 if (ipd_count == MAX_IPD_COUNT)
430 s390_handle_damage("too many ipd retries.");
431
432 spin_unlock(&ipd_lock);
433 }
434 else {
435 /* Processing damage -> stopping machine */
436 s390_handle_damage("received instruction processing "
437 "damage machine check.");
438 }
439 }
440 if (s390_revalidate_registers(mci)) {
441 if (umode) {
442 /*
443 * Couldn't restore all register contents while in
444 * user mode -> mark task for termination.
445 */
446 mcck->kill_task = 1;
447 mcck->mcck_code = *(unsigned long long *) mci;
448 set_thread_flag(TIF_MCCK_PENDING);
449 }
450 else
451 /*
452 * Couldn't restore all register contents while in
453 * kernel mode -> stopping machine.
454 */
455 s390_handle_damage("unable to revalidate registers.");
456 }
457
458 if (mci->cd) {
459 /* Timing facility damage */
460 s390_handle_damage("TOD clock damaged");
461 }
462
463 if (mci->ed && mci->ec) {
464 /* External damage */
465 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SYNC))
466 etr_sync_check();
467 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SWITCH))
468 etr_switch_to_local();
469 }
470
471 if (mci->se)
472 /* Storage error uncorrected */
473 s390_handle_damage("received storage error uncorrected "
474 "machine check.");
475
476 if (mci->ke)
477 /* Storage key-error uncorrected */
478 s390_handle_damage("received storage key-error uncorrected "
479 "machine check.");
480
481 if (mci->ds && mci->fa)
482 /* Storage degradation */
483 s390_handle_damage("received storage degradation machine "
484 "check.");
485
486 if (mci->cp) {
487 /* Channel report word pending */
488 mcck->channel_report = 1;
489 set_thread_flag(TIF_MCCK_PENDING);
490 }
491
492 if (mci->w) {
493 /* Warning pending */
494 mcck->warning = 1;
495 set_thread_flag(TIF_MCCK_PENDING);
496 }
497 lockdep_on();
498 }
499
500 /*
501 * s390_init_machine_check
502 *
503 * initialize machine check handling
504 */
505 static int
506 machine_check_init(void)
507 {
508 init_MUTEX_LOCKED(&m_sem);
509 ctl_set_bit(14, 25); /* enable external damage MCH */
510 ctl_set_bit(14, 27); /* enable system recovery MCH */
511 #ifdef CONFIG_MACHCHK_WARNING
512 ctl_set_bit(14, 24); /* enable warning MCH */
513 #endif
514 return 0;
515 }
516
517 /*
518 * Initialize the machine check handler really early to be able to
519 * catch all machine checks that happen during boot
520 */
521 arch_initcall(machine_check_init);
522
523 /*
524 * Machine checks for the channel subsystem must be enabled
525 * after the channel subsystem is initialized
526 */
527 static int __init
528 machine_check_crw_init (void)
529 {
530 struct task_struct *task;
531
532 task = kthread_run(s390_collect_crw_info, &m_sem, "kmcheck");
533 if (IS_ERR(task))
534 return PTR_ERR(task);
535 ctl_set_bit(14, 28); /* enable channel report MCH */
536 return 0;
537 }
538
539 device_initcall (machine_check_crw_init);
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