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1 /*
2 * Machine check handler
3 *
4 * Copyright IBM Corp. 2000, 2009
5 * Author(s): Ingo Adlung <adlung@de.ibm.com>,
6 * Martin Schwidefsky <schwidefsky@de.ibm.com>,
7 * Cornelia Huck <cornelia.huck@de.ibm.com>,
8 * Heiko Carstens <heiko.carstens@de.ibm.com>,
9 */
10
11 #include <linux/kernel_stat.h>
12 #include <linux/init.h>
13 #include <linux/errno.h>
14 #include <linux/hardirq.h>
15 #include <linux/time.h>
16 #include <linux/module.h>
17 #include <asm/lowcore.h>
18 #include <asm/smp.h>
19 #include <asm/etr.h>
20 #include <asm/cputime.h>
21 #include <asm/nmi.h>
22 #include <asm/crw.h>
23 #include <asm/switch_to.h>
24 #include <asm/fpu-internal.h>
25 #include <asm/ctl_reg.h>
26
27 struct mcck_struct {
28 int kill_task;
29 int channel_report;
30 int warning;
31 unsigned long long mcck_code;
32 };
33
34 static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck);
35
36 static void s390_handle_damage(char *msg)
37 {
38 smp_send_stop();
39 disabled_wait((unsigned long) __builtin_return_address(0));
40 while (1);
41 }
42
43 /*
44 * Main machine check handler function. Will be called with interrupts enabled
45 * or disabled and machine checks enabled or disabled.
46 */
47 void s390_handle_mcck(void)
48 {
49 unsigned long flags;
50 struct mcck_struct mcck;
51
52 /*
53 * Disable machine checks and get the current state of accumulated
54 * machine checks. Afterwards delete the old state and enable machine
55 * checks again.
56 */
57 local_irq_save(flags);
58 local_mcck_disable();
59 mcck = *this_cpu_ptr(&cpu_mcck);
60 memset(this_cpu_ptr(&cpu_mcck), 0, sizeof(mcck));
61 clear_cpu_flag(CIF_MCCK_PENDING);
62 local_mcck_enable();
63 local_irq_restore(flags);
64
65 if (mcck.channel_report)
66 crw_handle_channel_report();
67 /*
68 * A warning may remain for a prolonged period on the bare iron.
69 * (actually until the machine is powered off, or the problem is gone)
70 * So we just stop listening for the WARNING MCH and avoid continuously
71 * being interrupted. One caveat is however, that we must do this per
72 * processor and cannot use the smp version of ctl_clear_bit().
73 * On VM we only get one interrupt per virtally presented machinecheck.
74 * Though one suffices, we may get one interrupt per (virtual) cpu.
75 */
76 if (mcck.warning) { /* WARNING pending ? */
77 static int mchchk_wng_posted = 0;
78
79 /* Use single cpu clear, as we cannot handle smp here. */
80 __ctl_clear_bit(14, 24); /* Disable WARNING MCH */
81 if (xchg(&mchchk_wng_posted, 1) == 0)
82 kill_cad_pid(SIGPWR, 1);
83 }
84 if (mcck.kill_task) {
85 local_irq_enable();
86 printk(KERN_EMERG "mcck: Terminating task because of machine "
87 "malfunction (code 0x%016llx).\n", mcck.mcck_code);
88 printk(KERN_EMERG "mcck: task: %s, pid: %d.\n",
89 current->comm, current->pid);
90 do_exit(SIGSEGV);
91 }
92 }
93 EXPORT_SYMBOL_GPL(s390_handle_mcck);
94
95 /*
96 * returns 0 if all registers could be validated
97 * returns 1 otherwise
98 */
99 static int notrace s390_revalidate_registers(struct mci *mci)
100 {
101 int kill_task;
102 u64 zero;
103 void *fpt_save_area, *fpt_creg_save_area;
104
105 kill_task = 0;
106 zero = 0;
107
108 if (!mci->gr) {
109 /*
110 * General purpose registers couldn't be restored and have
111 * unknown contents. Process needs to be terminated.
112 */
113 kill_task = 1;
114 }
115 if (!mci->fp) {
116 /*
117 * Floating point registers can't be restored and
118 * therefore the process needs to be terminated.
119 */
120 kill_task = 1;
121 }
122 fpt_save_area = &S390_lowcore.floating_pt_save_area;
123 fpt_creg_save_area = &S390_lowcore.fpt_creg_save_area;
124 if (!mci->fc) {
125 /*
126 * Floating point control register can't be restored.
127 * Task will be terminated.
128 */
129 asm volatile("lfpc 0(%0)" : : "a" (&zero), "m" (zero));
130 kill_task = 1;
131 } else
132 asm volatile("lfpc 0(%0)" : : "a" (fpt_creg_save_area));
133
134 if (!MACHINE_HAS_VX) {
135 /* Revalidate floating point registers */
136 asm volatile(
137 " ld 0,0(%0)\n"
138 " ld 1,8(%0)\n"
139 " ld 2,16(%0)\n"
140 " ld 3,24(%0)\n"
141 " ld 4,32(%0)\n"
142 " ld 5,40(%0)\n"
143 " ld 6,48(%0)\n"
144 " ld 7,56(%0)\n"
145 " ld 8,64(%0)\n"
146 " ld 9,72(%0)\n"
147 " ld 10,80(%0)\n"
148 " ld 11,88(%0)\n"
149 " ld 12,96(%0)\n"
150 " ld 13,104(%0)\n"
151 " ld 14,112(%0)\n"
152 " ld 15,120(%0)\n"
153 : : "a" (fpt_save_area));
154 } else {
155 /* Revalidate vector registers */
156 union ctlreg0 cr0;
157
158 if (!mci->vr) {
159 /*
160 * Vector registers can't be restored and therefore
161 * the process needs to be terminated.
162 */
163 kill_task = 1;
164 }
165 cr0.val = S390_lowcore.cregs_save_area[0];
166 cr0.afp = cr0.vx = 1;
167 __ctl_load(cr0.val, 0, 0);
168 asm volatile(
169 " la 1,%0\n"
170 " .word 0xe70f,0x1000,0x0036\n" /* vlm 0,15,0(1) */
171 " .word 0xe70f,0x1100,0x0c36\n" /* vlm 16,31,256(1) */
172 : : "Q" (*(struct vx_array *)
173 &S390_lowcore.vector_save_area) : "1");
174 __ctl_load(S390_lowcore.cregs_save_area[0], 0, 0);
175 }
176 /* Revalidate access registers */
177 asm volatile(
178 " lam 0,15,0(%0)"
179 : : "a" (&S390_lowcore.access_regs_save_area));
180 if (!mci->ar) {
181 /*
182 * Access registers have unknown contents.
183 * Terminating task.
184 */
185 kill_task = 1;
186 }
187 /* Revalidate control registers */
188 if (!mci->cr) {
189 /*
190 * Control registers have unknown contents.
191 * Can't recover and therefore stopping machine.
192 */
193 s390_handle_damage("invalid control registers.");
194 } else {
195 asm volatile(
196 " lctlg 0,15,0(%0)"
197 : : "a" (&S390_lowcore.cregs_save_area));
198 }
199 /*
200 * We don't even try to revalidate the TOD register, since we simply
201 * can't write something sensible into that register.
202 */
203 /*
204 * See if we can revalidate the TOD programmable register with its
205 * old contents (should be zero) otherwise set it to zero.
206 */
207 if (!mci->pr)
208 asm volatile(
209 " sr 0,0\n"
210 " sckpf"
211 : : : "0", "cc");
212 else
213 asm volatile(
214 " l 0,0(%0)\n"
215 " sckpf"
216 : : "a" (&S390_lowcore.tod_progreg_save_area)
217 : "0", "cc");
218 /* Revalidate clock comparator register */
219 set_clock_comparator(S390_lowcore.clock_comparator);
220 /* Check if old PSW is valid */
221 if (!mci->wp)
222 /*
223 * Can't tell if we come from user or kernel mode
224 * -> stopping machine.
225 */
226 s390_handle_damage("old psw invalid.");
227
228 if (!mci->ms || !mci->pm || !mci->ia)
229 kill_task = 1;
230
231 return kill_task;
232 }
233
234 #define MAX_IPD_COUNT 29
235 #define MAX_IPD_TIME (5 * 60 * USEC_PER_SEC) /* 5 minutes */
236
237 #define ED_STP_ISLAND 6 /* External damage STP island check */
238 #define ED_STP_SYNC 7 /* External damage STP sync check */
239 #define ED_ETR_SYNC 12 /* External damage ETR sync check */
240 #define ED_ETR_SWITCH 13 /* External damage ETR switch to local */
241
242 /*
243 * machine check handler.
244 */
245 void notrace s390_do_machine_check(struct pt_regs *regs)
246 {
247 static int ipd_count;
248 static DEFINE_SPINLOCK(ipd_lock);
249 static unsigned long long last_ipd;
250 struct mcck_struct *mcck;
251 unsigned long long tmp;
252 struct mci *mci;
253 int umode;
254
255 nmi_enter();
256 inc_irq_stat(NMI_NMI);
257 mci = (struct mci *) &S390_lowcore.mcck_interruption_code;
258 mcck = this_cpu_ptr(&cpu_mcck);
259 umode = user_mode(regs);
260
261 if (mci->sd) {
262 /* System damage -> stopping machine */
263 s390_handle_damage("received system damage machine check.");
264 }
265 if (mci->pd) {
266 if (mci->b) {
267 /* Processing backup -> verify if we can survive this */
268 u64 z_mcic, o_mcic, t_mcic;
269 z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29);
270 o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
271 1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
272 1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 |
273 1ULL<<16);
274 t_mcic = *(u64 *)mci;
275
276 if (((t_mcic & z_mcic) != 0) ||
277 ((t_mcic & o_mcic) != o_mcic)) {
278 s390_handle_damage("processing backup machine "
279 "check with damage.");
280 }
281
282 /*
283 * Nullifying exigent condition, therefore we might
284 * retry this instruction.
285 */
286 spin_lock(&ipd_lock);
287 tmp = get_tod_clock();
288 if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME)
289 ipd_count++;
290 else
291 ipd_count = 1;
292 last_ipd = tmp;
293 if (ipd_count == MAX_IPD_COUNT)
294 s390_handle_damage("too many ipd retries.");
295 spin_unlock(&ipd_lock);
296 } else {
297 /* Processing damage -> stopping machine */
298 s390_handle_damage("received instruction processing "
299 "damage machine check.");
300 }
301 }
302 if (s390_revalidate_registers(mci)) {
303 if (umode) {
304 /*
305 * Couldn't restore all register contents while in
306 * user mode -> mark task for termination.
307 */
308 mcck->kill_task = 1;
309 mcck->mcck_code = *(unsigned long long *) mci;
310 set_cpu_flag(CIF_MCCK_PENDING);
311 } else {
312 /*
313 * Couldn't restore all register contents while in
314 * kernel mode -> stopping machine.
315 */
316 s390_handle_damage("unable to revalidate registers.");
317 }
318 }
319 if (mci->cd) {
320 /* Timing facility damage */
321 s390_handle_damage("TOD clock damaged");
322 }
323 if (mci->ed && mci->ec) {
324 /* External damage */
325 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SYNC))
326 etr_sync_check();
327 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SWITCH))
328 etr_switch_to_local();
329 if (S390_lowcore.external_damage_code & (1U << ED_STP_SYNC))
330 stp_sync_check();
331 if (S390_lowcore.external_damage_code & (1U << ED_STP_ISLAND))
332 stp_island_check();
333 }
334 if (mci->se)
335 /* Storage error uncorrected */
336 s390_handle_damage("received storage error uncorrected "
337 "machine check.");
338 if (mci->ke)
339 /* Storage key-error uncorrected */
340 s390_handle_damage("received storage key-error uncorrected "
341 "machine check.");
342 if (mci->ds && mci->fa)
343 /* Storage degradation */
344 s390_handle_damage("received storage degradation machine "
345 "check.");
346 if (mci->cp) {
347 /* Channel report word pending */
348 mcck->channel_report = 1;
349 set_cpu_flag(CIF_MCCK_PENDING);
350 }
351 if (mci->w) {
352 /* Warning pending */
353 mcck->warning = 1;
354 set_cpu_flag(CIF_MCCK_PENDING);
355 }
356 nmi_exit();
357 }
358
359 static int __init machine_check_init(void)
360 {
361 ctl_set_bit(14, 25); /* enable external damage MCH */
362 ctl_set_bit(14, 27); /* enable system recovery MCH */
363 ctl_set_bit(14, 24); /* enable warning MCH */
364 return 0;
365 }
366 early_initcall(machine_check_init);