Loading...
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
24struct mcck_struct {
25 int kill_task;
26 int channel_report;
27 int warning;
28 unsigned long long mcck_code;
29};
30
31static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck);
32
33static NORET_TYPE void s390_handle_damage(char *msg)
34{
35 smp_send_stop();
36 disabled_wait((unsigned long) __builtin_return_address(0));
37 while (1);
38}
39
40/*
41 * Main machine check handler function. Will be called with interrupts enabled
42 * or disabled and machine checks enabled or disabled.
43 */
44void s390_handle_mcck(void)
45{
46 unsigned long flags;
47 struct mcck_struct mcck;
48
49 /*
50 * Disable machine checks and get the current state of accumulated
51 * machine checks. Afterwards delete the old state and enable machine
52 * checks again.
53 */
54 local_irq_save(flags);
55 local_mcck_disable();
56 mcck = __get_cpu_var(cpu_mcck);
57 memset(&__get_cpu_var(cpu_mcck), 0, sizeof(struct mcck_struct));
58 clear_thread_flag(TIF_MCCK_PENDING);
59 local_mcck_enable();
60 local_irq_restore(flags);
61
62 if (mcck.channel_report)
63 crw_handle_channel_report();
64 /*
65 * A warning may remain for a prolonged period on the bare iron.
66 * (actually until the machine is powered off, or the problem is gone)
67 * So we just stop listening for the WARNING MCH and avoid continuously
68 * being interrupted. One caveat is however, that we must do this per
69 * processor and cannot use the smp version of ctl_clear_bit().
70 * On VM we only get one interrupt per virtally presented machinecheck.
71 * Though one suffices, we may get one interrupt per (virtual) cpu.
72 */
73 if (mcck.warning) { /* WARNING pending ? */
74 static int mchchk_wng_posted = 0;
75
76 /* Use single cpu clear, as we cannot handle smp here. */
77 __ctl_clear_bit(14, 24); /* Disable WARNING MCH */
78 if (xchg(&mchchk_wng_posted, 1) == 0)
79 kill_cad_pid(SIGPWR, 1);
80 }
81 if (mcck.kill_task) {
82 local_irq_enable();
83 printk(KERN_EMERG "mcck: Terminating task because of machine "
84 "malfunction (code 0x%016llx).\n", mcck.mcck_code);
85 printk(KERN_EMERG "mcck: task: %s, pid: %d.\n",
86 current->comm, current->pid);
87 do_exit(SIGSEGV);
88 }
89}
90EXPORT_SYMBOL_GPL(s390_handle_mcck);
91
92/*
93 * returns 0 if all registers could be validated
94 * returns 1 otherwise
95 */
96static int notrace s390_revalidate_registers(struct mci *mci)
97{
98 int kill_task;
99 u64 zero;
100 void *fpt_save_area, *fpt_creg_save_area;
101
102 kill_task = 0;
103 zero = 0;
104
105 if (!mci->gr) {
106 /*
107 * General purpose registers couldn't be restored and have
108 * unknown contents. Process needs to be terminated.
109 */
110 kill_task = 1;
111 }
112 if (!mci->fp) {
113 /*
114 * Floating point registers can't be restored and
115 * therefore the process needs to be terminated.
116 */
117 kill_task = 1;
118 }
119#ifndef CONFIG_64BIT
120 asm volatile(
121 " ld 0,0(%0)\n"
122 " ld 2,8(%0)\n"
123 " ld 4,16(%0)\n"
124 " ld 6,24(%0)"
125 : : "a" (&S390_lowcore.floating_pt_save_area));
126#endif
127
128 if (MACHINE_HAS_IEEE) {
129#ifdef CONFIG_64BIT
130 fpt_save_area = &S390_lowcore.floating_pt_save_area;
131 fpt_creg_save_area = &S390_lowcore.fpt_creg_save_area;
132#else
133 fpt_save_area = (void *) S390_lowcore.extended_save_area_addr;
134 fpt_creg_save_area = fpt_save_area + 128;
135#endif
136 if (!mci->fc) {
137 /*
138 * Floating point control register can't be restored.
139 * Task will be terminated.
140 */
141 asm volatile("lfpc 0(%0)" : : "a" (&zero), "m" (zero));
142 kill_task = 1;
143
144 } else
145 asm volatile("lfpc 0(%0)" : : "a" (fpt_creg_save_area));
146
147 asm volatile(
148 " ld 0,0(%0)\n"
149 " ld 1,8(%0)\n"
150 " ld 2,16(%0)\n"
151 " ld 3,24(%0)\n"
152 " ld 4,32(%0)\n"
153 " ld 5,40(%0)\n"
154 " ld 6,48(%0)\n"
155 " ld 7,56(%0)\n"
156 " ld 8,64(%0)\n"
157 " ld 9,72(%0)\n"
158 " ld 10,80(%0)\n"
159 " ld 11,88(%0)\n"
160 " ld 12,96(%0)\n"
161 " ld 13,104(%0)\n"
162 " ld 14,112(%0)\n"
163 " ld 15,120(%0)\n"
164 : : "a" (fpt_save_area));
165 }
166 /* Revalidate access registers */
167 asm volatile(
168 " lam 0,15,0(%0)"
169 : : "a" (&S390_lowcore.access_regs_save_area));
170 if (!mci->ar) {
171 /*
172 * Access registers have unknown contents.
173 * Terminating task.
174 */
175 kill_task = 1;
176 }
177 /* Revalidate control registers */
178 if (!mci->cr) {
179 /*
180 * Control registers have unknown contents.
181 * Can't recover and therefore stopping machine.
182 */
183 s390_handle_damage("invalid control registers.");
184 } else {
185#ifdef CONFIG_64BIT
186 asm volatile(
187 " lctlg 0,15,0(%0)"
188 : : "a" (&S390_lowcore.cregs_save_area));
189#else
190 asm volatile(
191 " lctl 0,15,0(%0)"
192 : : "a" (&S390_lowcore.cregs_save_area));
193#endif
194 }
195 /*
196 * We don't even try to revalidate the TOD register, since we simply
197 * can't write something sensible into that register.
198 */
199#ifdef CONFIG_64BIT
200 /*
201 * See if we can revalidate the TOD programmable register with its
202 * old contents (should be zero) otherwise set it to zero.
203 */
204 if (!mci->pr)
205 asm volatile(
206 " sr 0,0\n"
207 " sckpf"
208 : : : "0", "cc");
209 else
210 asm volatile(
211 " l 0,0(%0)\n"
212 " sckpf"
213 : : "a" (&S390_lowcore.tod_progreg_save_area)
214 : "0", "cc");
215#endif
216 /* Revalidate clock comparator register */
217 if (S390_lowcore.clock_comparator == -1)
218 set_clock_comparator(S390_lowcore.mcck_clock);
219 else
220 set_clock_comparator(S390_lowcore.clock_comparator);
221 /* Check if old PSW is valid */
222 if (!mci->wp)
223 /*
224 * Can't tell if we come from user or kernel mode
225 * -> stopping machine.
226 */
227 s390_handle_damage("old psw invalid.");
228
229 if (!mci->ms || !mci->pm || !mci->ia)
230 kill_task = 1;
231
232 return kill_task;
233}
234
235#define MAX_IPD_COUNT 29
236#define MAX_IPD_TIME (5 * 60 * USEC_PER_SEC) /* 5 minutes */
237
238#define ED_STP_ISLAND 6 /* External damage STP island check */
239#define ED_STP_SYNC 7 /* External damage STP sync check */
240#define ED_ETR_SYNC 12 /* External damage ETR sync check */
241#define ED_ETR_SWITCH 13 /* External damage ETR switch to local */
242
243/*
244 * machine check handler.
245 */
246void notrace s390_do_machine_check(struct pt_regs *regs)
247{
248 static int ipd_count;
249 static DEFINE_SPINLOCK(ipd_lock);
250 static unsigned long long last_ipd;
251 struct mcck_struct *mcck;
252 unsigned long long tmp;
253 struct mci *mci;
254 int umode;
255
256 nmi_enter();
257 s390_idle_check(regs, S390_lowcore.mcck_clock,
258 S390_lowcore.mcck_enter_timer);
259 kstat_cpu(smp_processor_id()).irqs[NMI_NMI]++;
260 mci = (struct mci *) &S390_lowcore.mcck_interruption_code;
261 mcck = &__get_cpu_var(cpu_mcck);
262 umode = user_mode(regs);
263
264 if (mci->sd) {
265 /* System damage -> stopping machine */
266 s390_handle_damage("received system damage machine check.");
267 }
268 if (mci->pd) {
269 if (mci->b) {
270 /* Processing backup -> verify if we can survive this */
271 u64 z_mcic, o_mcic, t_mcic;
272#ifdef CONFIG_64BIT
273 z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29);
274 o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
275 1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
276 1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 |
277 1ULL<<16);
278#else
279 z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<57 | 1ULL<<50 |
280 1ULL<<29);
281 o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
282 1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
283 1ULL<<30 | 1ULL<<20 | 1ULL<<17 | 1ULL<<16);
284#endif
285 t_mcic = *(u64 *)mci;
286
287 if (((t_mcic & z_mcic) != 0) ||
288 ((t_mcic & o_mcic) != o_mcic)) {
289 s390_handle_damage("processing backup machine "
290 "check with damage.");
291 }
292
293 /*
294 * Nullifying exigent condition, therefore we might
295 * retry this instruction.
296 */
297 spin_lock(&ipd_lock);
298 tmp = get_clock();
299 if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME)
300 ipd_count++;
301 else
302 ipd_count = 1;
303 last_ipd = tmp;
304 if (ipd_count == MAX_IPD_COUNT)
305 s390_handle_damage("too many ipd retries.");
306 spin_unlock(&ipd_lock);
307 } else {
308 /* Processing damage -> stopping machine */
309 s390_handle_damage("received instruction processing "
310 "damage machine check.");
311 }
312 }
313 if (s390_revalidate_registers(mci)) {
314 if (umode) {
315 /*
316 * Couldn't restore all register contents while in
317 * user mode -> mark task for termination.
318 */
319 mcck->kill_task = 1;
320 mcck->mcck_code = *(unsigned long long *) mci;
321 set_thread_flag(TIF_MCCK_PENDING);
322 } else {
323 /*
324 * Couldn't restore all register contents while in
325 * kernel mode -> stopping machine.
326 */
327 s390_handle_damage("unable to revalidate registers.");
328 }
329 }
330 if (mci->cd) {
331 /* Timing facility damage */
332 s390_handle_damage("TOD clock damaged");
333 }
334 if (mci->ed && mci->ec) {
335 /* External damage */
336 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SYNC))
337 etr_sync_check();
338 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SWITCH))
339 etr_switch_to_local();
340 if (S390_lowcore.external_damage_code & (1U << ED_STP_SYNC))
341 stp_sync_check();
342 if (S390_lowcore.external_damage_code & (1U << ED_STP_ISLAND))
343 stp_island_check();
344 }
345 if (mci->se)
346 /* Storage error uncorrected */
347 s390_handle_damage("received storage error uncorrected "
348 "machine check.");
349 if (mci->ke)
350 /* Storage key-error uncorrected */
351 s390_handle_damage("received storage key-error uncorrected "
352 "machine check.");
353 if (mci->ds && mci->fa)
354 /* Storage degradation */
355 s390_handle_damage("received storage degradation machine "
356 "check.");
357 if (mci->cp) {
358 /* Channel report word pending */
359 mcck->channel_report = 1;
360 set_thread_flag(TIF_MCCK_PENDING);
361 }
362 if (mci->w) {
363 /* Warning pending */
364 mcck->warning = 1;
365 set_thread_flag(TIF_MCCK_PENDING);
366 }
367 nmi_exit();
368}
369
370static int __init machine_check_init(void)
371{
372 ctl_set_bit(14, 25); /* enable external damage MCH */
373 ctl_set_bit(14, 27); /* enable system recovery MCH */
374 ctl_set_bit(14, 24); /* enable warning MCH */
375 return 0;
376}
377arch_initcall(machine_check_init);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Machine check handler
4 *
5 * Copyright IBM Corp. 2000, 2009
6 * Author(s): Ingo Adlung <adlung@de.ibm.com>,
7 * Martin Schwidefsky <schwidefsky@de.ibm.com>,
8 * Cornelia Huck <cornelia.huck@de.ibm.com>,
9 */
10
11#include <linux/kernel_stat.h>
12#include <linux/init.h>
13#include <linux/errno.h>
14#include <linux/entry-common.h>
15#include <linux/hardirq.h>
16#include <linux/log2.h>
17#include <linux/kprobes.h>
18#include <linux/kmemleak.h>
19#include <linux/time.h>
20#include <linux/module.h>
21#include <linux/sched/signal.h>
22#include <linux/kvm_host.h>
23#include <linux/export.h>
24#include <asm/lowcore.h>
25#include <asm/ctlreg.h>
26#include <asm/fpu.h>
27#include <asm/smp.h>
28#include <asm/stp.h>
29#include <asm/cputime.h>
30#include <asm/nmi.h>
31#include <asm/crw.h>
32#include <asm/asm-offsets.h>
33#include <asm/pai.h>
34
35struct mcck_struct {
36 unsigned int kill_task : 1;
37 unsigned int channel_report : 1;
38 unsigned int warning : 1;
39 unsigned int stp_queue : 1;
40 unsigned long mcck_code;
41};
42
43static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck);
44
45static inline int nmi_needs_mcesa(void)
46{
47 return cpu_has_vx() || MACHINE_HAS_GS;
48}
49
50/*
51 * The initial machine check extended save area for the boot CPU.
52 * It will be replaced on the boot CPU reinit with an allocated
53 * structure. The structure is required for machine check happening
54 * early in the boot process.
55 */
56static struct mcesa boot_mcesa __aligned(MCESA_MAX_SIZE);
57
58void __init nmi_alloc_mcesa_early(u64 *mcesad)
59{
60 if (!nmi_needs_mcesa())
61 return;
62 *mcesad = __pa(&boot_mcesa);
63 if (MACHINE_HAS_GS)
64 *mcesad |= ilog2(MCESA_MAX_SIZE);
65}
66
67int nmi_alloc_mcesa(u64 *mcesad)
68{
69 unsigned long size;
70 void *origin;
71
72 *mcesad = 0;
73 if (!nmi_needs_mcesa())
74 return 0;
75 size = MACHINE_HAS_GS ? MCESA_MAX_SIZE : MCESA_MIN_SIZE;
76 origin = kmalloc(size, GFP_KERNEL);
77 if (!origin)
78 return -ENOMEM;
79 /* The pointer is stored with mcesa_bits ORed in */
80 kmemleak_not_leak(origin);
81 *mcesad = __pa(origin);
82 if (MACHINE_HAS_GS)
83 *mcesad |= ilog2(MCESA_MAX_SIZE);
84 return 0;
85}
86
87void nmi_free_mcesa(u64 *mcesad)
88{
89 if (!nmi_needs_mcesa())
90 return;
91 kfree(__va(*mcesad & MCESA_ORIGIN_MASK));
92}
93
94static __always_inline char *nmi_puts(char *dest, const char *src)
95{
96 while (*src)
97 *dest++ = *src++;
98 *dest = 0;
99 return dest;
100}
101
102static __always_inline char *u64_to_hex(char *dest, u64 val)
103{
104 int i, num;
105
106 for (i = 1; i <= 16; i++) {
107 num = (val >> (64 - 4 * i)) & 0xf;
108 if (num >= 10)
109 *dest++ = 'A' + num - 10;
110 else
111 *dest++ = '0' + num;
112 }
113 *dest = 0;
114 return dest;
115}
116
117static notrace void s390_handle_damage(void)
118{
119 union ctlreg0 cr0, cr0_new;
120 char message[100];
121 psw_t psw_save;
122 char *ptr;
123
124 smp_emergency_stop();
125 diag_amode31_ops.diag308_reset();
126 ptr = nmi_puts(message, "System stopped due to unrecoverable machine check, code: 0x");
127 u64_to_hex(ptr, S390_lowcore.mcck_interruption_code);
128
129 /*
130 * Disable low address protection and make machine check new PSW a
131 * disabled wait PSW. Any additional machine check cannot be handled.
132 */
133 local_ctl_store(0, &cr0.reg);
134 cr0_new = cr0;
135 cr0_new.lap = 0;
136 local_ctl_load(0, &cr0_new.reg);
137 psw_save = S390_lowcore.mcck_new_psw;
138 psw_bits(S390_lowcore.mcck_new_psw).io = 0;
139 psw_bits(S390_lowcore.mcck_new_psw).ext = 0;
140 psw_bits(S390_lowcore.mcck_new_psw).wait = 1;
141 sclp_emergency_printk(message);
142
143 /*
144 * Restore machine check new PSW and control register 0 to original
145 * values. This makes possible system dump analysis easier.
146 */
147 S390_lowcore.mcck_new_psw = psw_save;
148 local_ctl_load(0, &cr0.reg);
149 disabled_wait();
150 while (1);
151}
152NOKPROBE_SYMBOL(s390_handle_damage);
153
154/*
155 * Main machine check handler function. Will be called with interrupts disabled
156 * and machine checks enabled.
157 */
158void s390_handle_mcck(void)
159{
160 struct mcck_struct mcck;
161 unsigned long mflags;
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_mcck_save(mflags);
169 mcck = *this_cpu_ptr(&cpu_mcck);
170 memset(this_cpu_ptr(&cpu_mcck), 0, sizeof(mcck));
171 local_mcck_restore(mflags);
172
173 if (mcck.channel_report)
174 crw_handle_channel_report();
175 /*
176 * A warning may remain for a prolonged period on the bare iron.
177 * (actually until the machine is powered off, or the problem is gone)
178 * So we just stop listening for the WARNING MCH and avoid continuously
179 * being interrupted. One caveat is however, that we must do this per
180 * processor and cannot use the smp version of ctl_clear_bit().
181 * On VM we only get one interrupt per virtally presented machinecheck.
182 * Though one suffices, we may get one interrupt per (virtual) cpu.
183 */
184 if (mcck.warning) { /* WARNING pending ? */
185 static int mchchk_wng_posted = 0;
186
187 /* Use single cpu clear, as we cannot handle smp here. */
188 local_ctl_clear_bit(14, CR14_WARNING_SUBMASK_BIT);
189 if (xchg(&mchchk_wng_posted, 1) == 0)
190 kill_cad_pid(SIGPWR, 1);
191 }
192 if (mcck.stp_queue)
193 stp_queue_work();
194 if (mcck.kill_task) {
195 printk(KERN_EMERG "mcck: Terminating task because of machine "
196 "malfunction (code 0x%016lx).\n", mcck.mcck_code);
197 printk(KERN_EMERG "mcck: task: %s, pid: %d.\n",
198 current->comm, current->pid);
199 if (is_global_init(current))
200 panic("mcck: Attempting to kill init!\n");
201 do_send_sig_info(SIGKILL, SEND_SIG_PRIV, current, PIDTYPE_PID);
202 }
203}
204
205/**
206 * nmi_registers_valid - verify if registers are valid
207 * @mci: machine check interruption code
208 *
209 * Inspect a machine check interruption code and verify if all required
210 * registers are valid. For some registers the corresponding validity bit is
211 * ignored and the registers are set to the expected value.
212 * Returns true if all registers are valid, otherwise false.
213 */
214static bool notrace nmi_registers_valid(union mci mci)
215{
216 union ctlreg2 cr2;
217
218 /*
219 * The getcpu vdso syscall reads the CPU number from the programmable
220 * field of the TOD clock. Disregard the TOD programmable register
221 * validity bit and load the CPU number into the TOD programmable field
222 * unconditionally.
223 */
224 set_tod_programmable_field(raw_smp_processor_id());
225 /*
226 * Set the clock comparator register to the next expected value.
227 */
228 set_clock_comparator(S390_lowcore.clock_comparator);
229 if (!mci.gr || !mci.fp || !mci.fc)
230 return false;
231 /*
232 * The vector validity must only be checked if not running a
233 * KVM guest. For KVM guests the machine check is forwarded by
234 * KVM and it is the responsibility of the guest to take
235 * appropriate actions. The host vector or FPU values have been
236 * saved by KVM and will be restored by KVM.
237 */
238 if (!mci.vr && !test_cpu_flag(CIF_MCCK_GUEST))
239 return false;
240 if (!mci.ar)
241 return false;
242 /*
243 * Two cases for guarded storage registers:
244 * - machine check in kernel or userspace
245 * - machine check while running SIE (KVM guest)
246 * For kernel or userspace the userspace values of guarded storage
247 * control can not be recreated, the process must be terminated.
248 * For SIE the guest values of guarded storage can not be recreated.
249 * This is either due to a bug or due to GS being disabled in the
250 * guest. The guest will be notified by KVM code and the guests machine
251 * check handling must take care of this. The host values are saved by
252 * KVM and are not affected.
253 */
254 cr2.reg = S390_lowcore.cregs_save_area[2];
255 if (cr2.gse && !mci.gs && !test_cpu_flag(CIF_MCCK_GUEST))
256 return false;
257 if (!mci.ms || !mci.pm || !mci.ia)
258 return false;
259 return true;
260}
261NOKPROBE_SYMBOL(nmi_registers_valid);
262
263/*
264 * Backup the guest's machine check info to its description block
265 */
266static void notrace s390_backup_mcck_info(struct pt_regs *regs)
267{
268 struct mcck_volatile_info *mcck_backup;
269 struct sie_page *sie_page;
270
271 /* r14 contains the sie block, which was set in sie64a */
272 struct kvm_s390_sie_block *sie_block = phys_to_virt(regs->gprs[14]);
273
274 if (sie_block == NULL)
275 /* Something's seriously wrong, stop system. */
276 s390_handle_damage();
277
278 sie_page = container_of(sie_block, struct sie_page, sie_block);
279 mcck_backup = &sie_page->mcck_info;
280 mcck_backup->mcic = S390_lowcore.mcck_interruption_code &
281 ~(MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE);
282 mcck_backup->ext_damage_code = S390_lowcore.external_damage_code;
283 mcck_backup->failing_storage_address
284 = S390_lowcore.failing_storage_address;
285}
286NOKPROBE_SYMBOL(s390_backup_mcck_info);
287
288#define MAX_IPD_COUNT 29
289#define MAX_IPD_TIME (5 * 60 * USEC_PER_SEC) /* 5 minutes */
290
291#define ED_STP_ISLAND 6 /* External damage STP island check */
292#define ED_STP_SYNC 7 /* External damage STP sync check */
293
294#define MCCK_CODE_NO_GUEST (MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE)
295
296/*
297 * machine check handler.
298 */
299void notrace s390_do_machine_check(struct pt_regs *regs)
300{
301 static int ipd_count;
302 static DEFINE_SPINLOCK(ipd_lock);
303 static unsigned long long last_ipd;
304 struct mcck_struct *mcck;
305 unsigned long long tmp;
306 irqentry_state_t irq_state;
307 union mci mci;
308 unsigned long mcck_dam_code;
309 int mcck_pending = 0;
310
311 irq_state = irqentry_nmi_enter(regs);
312
313 if (user_mode(regs))
314 update_timer_mcck();
315 inc_irq_stat(NMI_NMI);
316 mci.val = S390_lowcore.mcck_interruption_code;
317 mcck = this_cpu_ptr(&cpu_mcck);
318
319 /*
320 * Reinject the instruction processing damages' machine checks
321 * including Delayed Access Exception into the guest
322 * instead of damaging the host if they happen in the guest.
323 */
324 if (mci.pd && !test_cpu_flag(CIF_MCCK_GUEST)) {
325 if (mci.b) {
326 /* Processing backup -> verify if we can survive this */
327 u64 z_mcic, o_mcic, t_mcic;
328 z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29);
329 o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
330 1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
331 1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 |
332 1ULL<<16);
333 t_mcic = mci.val;
334
335 if (((t_mcic & z_mcic) != 0) ||
336 ((t_mcic & o_mcic) != o_mcic)) {
337 s390_handle_damage();
338 }
339
340 /*
341 * Nullifying exigent condition, therefore we might
342 * retry this instruction.
343 */
344 spin_lock(&ipd_lock);
345 tmp = get_tod_clock();
346 if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME)
347 ipd_count++;
348 else
349 ipd_count = 1;
350 last_ipd = tmp;
351 if (ipd_count == MAX_IPD_COUNT)
352 s390_handle_damage();
353 spin_unlock(&ipd_lock);
354 } else {
355 /* Processing damage -> stopping machine */
356 s390_handle_damage();
357 }
358 }
359 if (!nmi_registers_valid(mci)) {
360 if (!user_mode(regs))
361 s390_handle_damage();
362 /*
363 * Couldn't restore all register contents for the
364 * user space process -> mark task for termination.
365 */
366 mcck->kill_task = 1;
367 mcck->mcck_code = mci.val;
368 mcck_pending = 1;
369 }
370
371 /*
372 * Backup the machine check's info if it happens when the guest
373 * is running.
374 */
375 if (test_cpu_flag(CIF_MCCK_GUEST))
376 s390_backup_mcck_info(regs);
377
378 if (mci.cd) {
379 /* Timing facility damage */
380 s390_handle_damage();
381 }
382 if (mci.ed && mci.ec) {
383 /* External damage */
384 if (S390_lowcore.external_damage_code & (1U << ED_STP_SYNC))
385 mcck->stp_queue |= stp_sync_check();
386 if (S390_lowcore.external_damage_code & (1U << ED_STP_ISLAND))
387 mcck->stp_queue |= stp_island_check();
388 mcck_pending = 1;
389 }
390 /*
391 * Reinject storage related machine checks into the guest if they
392 * happen when the guest is running.
393 */
394 if (!test_cpu_flag(CIF_MCCK_GUEST)) {
395 /* Storage error uncorrected */
396 if (mci.se)
397 s390_handle_damage();
398 /* Storage key-error uncorrected */
399 if (mci.ke)
400 s390_handle_damage();
401 /* Storage degradation */
402 if (mci.ds && mci.fa)
403 s390_handle_damage();
404 }
405 if (mci.cp) {
406 /* Channel report word pending */
407 mcck->channel_report = 1;
408 mcck_pending = 1;
409 }
410 if (mci.w) {
411 /* Warning pending */
412 mcck->warning = 1;
413 mcck_pending = 1;
414 }
415
416 /*
417 * If there are only Channel Report Pending and External Damage
418 * machine checks, they will not be reinjected into the guest
419 * because they refer to host conditions only.
420 */
421 mcck_dam_code = (mci.val & MCIC_SUBCLASS_MASK);
422 if (test_cpu_flag(CIF_MCCK_GUEST) &&
423 (mcck_dam_code & MCCK_CODE_NO_GUEST) != mcck_dam_code) {
424 /* Set exit reason code for host's later handling */
425 *((long *)(regs->gprs[15] + __SF_SIE_REASON)) = -EINTR;
426 }
427 clear_cpu_flag(CIF_MCCK_GUEST);
428
429 if (mcck_pending)
430 schedule_mcck_handler();
431
432 irqentry_nmi_exit(regs, irq_state);
433}
434NOKPROBE_SYMBOL(s390_do_machine_check);
435
436static int __init machine_check_init(void)
437{
438 system_ctl_set_bit(14, CR14_EXTERNAL_DAMAGE_SUBMASK_BIT);
439 system_ctl_set_bit(14, CR14_RECOVERY_SUBMASK_BIT);
440 system_ctl_set_bit(14, CR14_WARNING_SUBMASK_BIT);
441 return 0;
442}
443early_initcall(machine_check_init);