[S390] Inline assembly cleanup.
[linux-2.6.git] / 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(
257                 "       ld      0,0(%0)\n"
258                 "       ld      2,8(%0)\n"
259                 "       ld      4,16(%0)\n"
260                 "       ld      6,24(%0)"
261                 : : "a" (&S390_lowcore.floating_pt_save_area));
262 #endif
263
264         if (MACHINE_HAS_IEEE) {
265 #ifdef CONFIG_64BIT
266                 fpt_save_area = &S390_lowcore.floating_pt_save_area;
267                 fpt_creg_save_area = &S390_lowcore.fpt_creg_save_area;
268 #else
269                 fpt_save_area = (void *) S390_lowcore.extended_save_area_addr;
270                 fpt_creg_save_area = fpt_save_area+128;
271 #endif
272                 /* Floating point control register */
273                 if (!mci->fc) {
274                         /*
275                          * Floating point control register can't be restored.
276                          * Task will be terminated.
277                          */
278                         asm volatile("lfpc 0(%0)" : : "a" (&zero), "m" (zero));
279                         kill_task = 1;
280
281                 } else
282                         asm volatile("lfpc 0(%0)" : : "a" (fpt_creg_save_area));
283
284                 asm volatile(
285                         "       ld      0,0(%0)\n"
286                         "       ld      1,8(%0)\n"
287                         "       ld      2,16(%0)\n"
288                         "       ld      3,24(%0)\n"
289                         "       ld      4,32(%0)\n"
290                         "       ld      5,40(%0)\n"
291                         "       ld      6,48(%0)\n"
292                         "       ld      7,56(%0)\n"
293                         "       ld      8,64(%0)\n"
294                         "       ld      9,72(%0)\n"
295                         "       ld      10,80(%0)\n"
296                         "       ld      11,88(%0)\n"
297                         "       ld      12,96(%0)\n"
298                         "       ld      13,104(%0)\n"
299                         "       ld      14,112(%0)\n"
300                         "       ld      15,120(%0)\n"
301                         : : "a" (fpt_save_area));
302         }
303
304         /* Revalidate access registers */
305         asm volatile(
306                 "       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(
325                         "       lctlg   0,15,0(%0)"
326                         : : "a" (&S390_lowcore.cregs_save_area));
327 #else
328                 asm volatile(
329                         "       lctl    0,15,0(%0)"
330                         : : "a" (&S390_lowcore.cregs_save_area));
331 #endif
332
333         /*
334          * We don't even try to revalidate the TOD register, since we simply
335          * can't write something sensible into that register.
336          */
337
338 #ifdef CONFIG_64BIT
339         /*
340          * See if we can revalidate the TOD programmable register with its
341          * old contents (should be zero) otherwise set it to zero.
342          */
343         if (!mci->pr)
344                 asm volatile(
345                         "       sr      0,0\n"
346                         "       sckpf"
347                         : : : "0", "cc");
348         else
349                 asm volatile(
350                         "       l       0,0(%0)\n"
351                         "       sckpf"
352                         : : "a" (&S390_lowcore.tod_progreg_save_area)
353                         : "0", "cc");
354 #endif
355
356         /* Revalidate clock comparator register */
357         asm volatile(
358                 "       stck    0(%1)\n"
359                 "       sckc    0(%1)"
360                 : "=m" (tmpclock) : "a" (&(tmpclock)) : "cc", "memory");
361
362         /* Check if old PSW is valid */
363         if (!mci->wp)
364                 /*
365                  * Can't tell if we come from user or kernel mode
366                  * -> stopping machine.
367                  */
368                 s390_handle_damage("old psw invalid.");
369
370         if (!mci->ms || !mci->pm || !mci->ia)
371                 kill_task = 1;
372
373         return kill_task;
374 }
375
376 #define MAX_IPD_COUNT   29
377 #define MAX_IPD_TIME    (5 * 60 * USEC_PER_SEC) /* 5 minutes */
378
379 /*
380  * machine check handler.
381  */
382 void
383 s390_do_machine_check(struct pt_regs *regs)
384 {
385         static DEFINE_SPINLOCK(ipd_lock);
386         static unsigned long long last_ipd;
387         static int ipd_count;
388         unsigned long long tmp;
389         struct mci *mci;
390         struct mcck_struct *mcck;
391         int umode;
392
393         lockdep_off();
394
395         mci = (struct mci *) &S390_lowcore.mcck_interruption_code;
396         mcck = &__get_cpu_var(cpu_mcck);
397         umode = user_mode(regs);
398
399         if (mci->sd)
400                 /* System damage -> stopping machine */
401                 s390_handle_damage("received system damage machine check.");
402
403         if (mci->pd) {
404                 if (mci->b) {
405                         /* Processing backup -> verify if we can survive this */
406                         u64 z_mcic, o_mcic, t_mcic;
407 #ifdef CONFIG_64BIT
408                         z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29);
409                         o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
410                                   1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
411                                   1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 |
412                                   1ULL<<16);
413 #else
414                         z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<57 | 1ULL<<50 |
415                                   1ULL<<29);
416                         o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
417                                   1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
418                                   1ULL<<30 | 1ULL<<20 | 1ULL<<17 | 1ULL<<16);
419 #endif
420                         t_mcic = *(u64 *)mci;
421
422                         if (((t_mcic & z_mcic) != 0) ||
423                             ((t_mcic & o_mcic) != o_mcic)) {
424                                 s390_handle_damage("processing backup machine "
425                                                    "check with damage.");
426                         }
427
428                         /*
429                          * Nullifying exigent condition, therefore we might
430                          * retry this instruction.
431                          */
432
433                         spin_lock(&ipd_lock);
434
435                         tmp = get_clock();
436
437                         if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME)
438                                 ipd_count++;
439                         else
440                                 ipd_count = 1;
441
442                         last_ipd = tmp;
443
444                         if (ipd_count == MAX_IPD_COUNT)
445                                 s390_handle_damage("too many ipd retries.");
446
447                         spin_unlock(&ipd_lock);
448                 }
449                 else {
450                         /* Processing damage -> stopping machine */
451                         s390_handle_damage("received instruction processing "
452                                            "damage machine check.");
453                 }
454         }
455         if (s390_revalidate_registers(mci)) {
456                 if (umode) {
457                         /*
458                          * Couldn't restore all register contents while in
459                          * user mode -> mark task for termination.
460                          */
461                         mcck->kill_task = 1;
462                         mcck->mcck_code = *(unsigned long long *) mci;
463                         set_thread_flag(TIF_MCCK_PENDING);
464                 }
465                 else
466                         /*
467                          * Couldn't restore all register contents while in
468                          * kernel mode -> stopping machine.
469                          */
470                         s390_handle_damage("unable to revalidate registers.");
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_clear_bit(14, 25);  /* disable 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         kthread_run(s390_collect_crw_info, &m_sem, "kmcheck");
533         ctl_set_bit(14, 28);    /* enable channel report MCH */
534         return 0;
535 }
536
537 device_initcall (machine_check_crw_init);