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