1 // SPDX-License-Identifier: GPL-2.0
3 * Machine check handler
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>,
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>
27 #include <asm/cputime.h>
30 #include <asm/switch_to.h>
31 #include <asm/ctl_reg.h>
32 #include <asm/asm-offsets.h>
34 #include <asm/vx-insn.h>
37 unsigned int kill_task : 1;
38 unsigned int channel_report : 1;
39 unsigned int warning : 1;
40 unsigned int stp_queue : 1;
41 unsigned long mcck_code;
44 static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck);
46 static inline int nmi_needs_mcesa(void)
48 return MACHINE_HAS_VX || MACHINE_HAS_GS;
52 * The initial machine check extended save area for the boot CPU.
53 * It will be replaced on the boot CPU reinit with an allocated
54 * structure. The structure is required for machine check happening
55 * early in the boot process.
57 static struct mcesa boot_mcesa __aligned(MCESA_MAX_SIZE);
59 void __init nmi_alloc_mcesa_early(u64 *mcesad)
61 if (!nmi_needs_mcesa())
63 *mcesad = __pa(&boot_mcesa);
65 *mcesad |= ilog2(MCESA_MAX_SIZE);
68 int nmi_alloc_mcesa(u64 *mcesad)
74 if (!nmi_needs_mcesa())
76 size = MACHINE_HAS_GS ? MCESA_MAX_SIZE : MCESA_MIN_SIZE;
77 origin = kmalloc(size, GFP_KERNEL);
80 /* The pointer is stored with mcesa_bits ORed in */
81 kmemleak_not_leak(origin);
82 *mcesad = __pa(origin);
84 *mcesad |= ilog2(MCESA_MAX_SIZE);
88 void nmi_free_mcesa(u64 *mcesad)
90 if (!nmi_needs_mcesa())
92 kfree(__va(*mcesad & MCESA_ORIGIN_MASK));
95 static __always_inline char *nmi_puts(char *dest, const char *src)
103 static __always_inline char *u64_to_hex(char *dest, u64 val)
107 for (i = 1; i <= 16; i++) {
108 num = (val >> (64 - 4 * i)) & 0xf;
110 *dest++ = 'A' + num - 10;
118 static notrace void s390_handle_damage(void)
120 union ctlreg0 cr0, cr0_new;
125 smp_emergency_stop();
126 diag_amode31_ops.diag308_reset();
127 ptr = nmi_puts(message, "System stopped due to unrecoverable machine check, code: 0x");
128 u64_to_hex(ptr, S390_lowcore.mcck_interruption_code);
131 * Disable low address protection and make machine check new PSW a
132 * disabled wait PSW. Any additional machine check cannot be handled.
134 __ctl_store(cr0.val, 0, 0);
137 __ctl_load(cr0_new.val, 0, 0);
138 psw_save = S390_lowcore.mcck_new_psw;
139 psw_bits(S390_lowcore.mcck_new_psw).io = 0;
140 psw_bits(S390_lowcore.mcck_new_psw).ext = 0;
141 psw_bits(S390_lowcore.mcck_new_psw).wait = 1;
142 sclp_emergency_printk(message);
145 * Restore machine check new PSW and control register 0 to original
146 * values. This makes possible system dump analysis easier.
148 S390_lowcore.mcck_new_psw = psw_save;
149 __ctl_load(cr0.val, 0, 0);
153 NOKPROBE_SYMBOL(s390_handle_damage);
156 * Main machine check handler function. Will be called with interrupts disabled
157 * and machine checks enabled.
159 void s390_handle_mcck(void)
161 struct mcck_struct mcck;
164 * Disable machine checks and get the current state of accumulated
165 * machine checks. Afterwards delete the old state and enable machine
168 local_mcck_disable();
169 mcck = *this_cpu_ptr(&cpu_mcck);
170 memset(this_cpu_ptr(&cpu_mcck), 0, sizeof(mcck));
173 if (mcck.channel_report)
174 crw_handle_channel_report();
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.
184 if (mcck.warning) { /* WARNING pending ? */
185 static int mchchk_wng_posted = 0;
187 /* Use single cpu clear, as we cannot handle smp here. */
188 __ctl_clear_bit(14, 24); /* Disable WARNING MCH */
189 if (xchg(&mchchk_wng_posted, 1) == 0)
190 kill_cad_pid(SIGPWR, 1);
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);
206 * returns 0 if register contents could be validated
207 * returns 1 otherwise
209 static int notrace s390_validate_registers(union mci mci)
220 if (!mci.gr || !mci.fp)
222 fpt_save_area = &S390_lowcore.floating_pt_save_area;
233 : "Q" (S390_lowcore.fpt_creg_save_area));
236 mcesa = __va(S390_lowcore.mcesad & MCESA_ORIGIN_MASK);
237 if (!MACHINE_HAS_VX) {
238 /* Validate floating point registers */
257 : "a" (fpt_save_area)
260 /* Validate vector registers */
264 * The vector validity must only be checked if not running a
265 * KVM guest. For KVM guests the machine check is forwarded by
266 * KVM and it is the responsibility of the guest to take
267 * appropriate actions. The host vector or FPU values have been
268 * saved by KVM and will be restored by KVM.
270 if (!mci.vr && !test_cpu_flag(CIF_MCCK_GUEST))
272 cr0.val = S390_lowcore.cregs_save_area[0];
273 cr0.afp = cr0.vx = 1;
274 __ctl_load(cr0.val, 0, 0);
280 : "Q" (*(struct vx_array *)mcesa->vector_save_area)
282 __ctl_load(S390_lowcore.cregs_save_area[0], 0, 0);
284 /* Validate access registers */
288 : "a" (&S390_lowcore.access_regs_save_area)
292 /* Validate guarded storage registers */
293 cr2.val = S390_lowcore.cregs_save_area[2];
298 * - machine check in kernel or userspace
299 * - machine check while running SIE (KVM guest)
300 * For kernel or userspace the userspace values of
301 * guarded storage control can not be recreated, the
302 * process must be terminated.
303 * For SIE the guest values of guarded storage can not
304 * be recreated. This is either due to a bug or due to
305 * GS being disabled in the guest. The guest will be
306 * notified by KVM code and the guests machine check
307 * handling must take care of this. The host values
308 * are saved by KVM and are not affected.
310 if (!test_cpu_flag(CIF_MCCK_GUEST))
313 load_gs_cb((struct gs_cb *)mcesa->guarded_storage_save_area);
317 * The getcpu vdso syscall reads CPU number from the programmable
318 * field of the TOD clock. Disregard the TOD programmable register
319 * validity bit and load the CPU number into the TOD programmable
320 * field unconditionally.
322 set_tod_programmable_field(raw_smp_processor_id());
323 /* Validate clock comparator register */
324 set_clock_comparator(S390_lowcore.clock_comparator);
326 if (!mci.ms || !mci.pm || !mci.ia)
331 NOKPROBE_SYMBOL(s390_validate_registers);
334 * Backup the guest's machine check info to its description block
336 static void notrace s390_backup_mcck_info(struct pt_regs *regs)
338 struct mcck_volatile_info *mcck_backup;
339 struct sie_page *sie_page;
341 /* r14 contains the sie block, which was set in sie64a */
342 struct kvm_s390_sie_block *sie_block = phys_to_virt(regs->gprs[14]);
344 if (sie_block == NULL)
345 /* Something's seriously wrong, stop system. */
346 s390_handle_damage();
348 sie_page = container_of(sie_block, struct sie_page, sie_block);
349 mcck_backup = &sie_page->mcck_info;
350 mcck_backup->mcic = S390_lowcore.mcck_interruption_code &
351 ~(MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE);
352 mcck_backup->ext_damage_code = S390_lowcore.external_damage_code;
353 mcck_backup->failing_storage_address
354 = S390_lowcore.failing_storage_address;
356 NOKPROBE_SYMBOL(s390_backup_mcck_info);
358 #define MAX_IPD_COUNT 29
359 #define MAX_IPD_TIME (5 * 60 * USEC_PER_SEC) /* 5 minutes */
361 #define ED_STP_ISLAND 6 /* External damage STP island check */
362 #define ED_STP_SYNC 7 /* External damage STP sync check */
364 #define MCCK_CODE_NO_GUEST (MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE)
367 * machine check handler.
369 void notrace s390_do_machine_check(struct pt_regs *regs)
371 static int ipd_count;
372 static DEFINE_SPINLOCK(ipd_lock);
373 static unsigned long long last_ipd;
374 struct mcck_struct *mcck;
375 unsigned long long tmp;
376 irqentry_state_t irq_state;
378 unsigned long mcck_dam_code;
379 int mcck_pending = 0;
381 irq_state = irqentry_nmi_enter(regs);
385 inc_irq_stat(NMI_NMI);
386 mci.val = S390_lowcore.mcck_interruption_code;
387 mcck = this_cpu_ptr(&cpu_mcck);
390 * Reinject the instruction processing damages' machine checks
391 * including Delayed Access Exception into the guest
392 * instead of damaging the host if they happen in the guest.
394 if (mci.pd && !test_cpu_flag(CIF_MCCK_GUEST)) {
396 /* Processing backup -> verify if we can survive this */
397 u64 z_mcic, o_mcic, t_mcic;
398 z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29);
399 o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
400 1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
401 1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 |
405 if (((t_mcic & z_mcic) != 0) ||
406 ((t_mcic & o_mcic) != o_mcic)) {
407 s390_handle_damage();
411 * Nullifying exigent condition, therefore we might
412 * retry this instruction.
414 spin_lock(&ipd_lock);
415 tmp = get_tod_clock();
416 if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME)
421 if (ipd_count == MAX_IPD_COUNT)
422 s390_handle_damage();
423 spin_unlock(&ipd_lock);
425 /* Processing damage -> stopping machine */
426 s390_handle_damage();
429 if (s390_validate_registers(mci)) {
430 if (!user_mode(regs))
431 s390_handle_damage();
433 * Couldn't restore all register contents for the
434 * user space process -> mark task for termination.
437 mcck->mcck_code = mci.val;
442 * Backup the machine check's info if it happens when the guest
445 if (test_cpu_flag(CIF_MCCK_GUEST))
446 s390_backup_mcck_info(regs);
449 /* Timing facility damage */
450 s390_handle_damage();
452 if (mci.ed && mci.ec) {
453 /* External damage */
454 if (S390_lowcore.external_damage_code & (1U << ED_STP_SYNC))
455 mcck->stp_queue |= stp_sync_check();
456 if (S390_lowcore.external_damage_code & (1U << ED_STP_ISLAND))
457 mcck->stp_queue |= stp_island_check();
461 * Reinject storage related machine checks into the guest if they
462 * happen when the guest is running.
464 if (!test_cpu_flag(CIF_MCCK_GUEST)) {
465 /* Storage error uncorrected */
467 s390_handle_damage();
468 /* Storage key-error uncorrected */
470 s390_handle_damage();
471 /* Storage degradation */
472 if (mci.ds && mci.fa)
473 s390_handle_damage();
476 /* Channel report word pending */
477 mcck->channel_report = 1;
481 /* Warning pending */
487 * If there are only Channel Report Pending and External Damage
488 * machine checks, they will not be reinjected into the guest
489 * because they refer to host conditions only.
491 mcck_dam_code = (mci.val & MCIC_SUBCLASS_MASK);
492 if (test_cpu_flag(CIF_MCCK_GUEST) &&
493 (mcck_dam_code & MCCK_CODE_NO_GUEST) != mcck_dam_code) {
494 /* Set exit reason code for host's later handling */
495 *((long *)(regs->gprs[15] + __SF_SIE_REASON)) = -EINTR;
497 clear_cpu_flag(CIF_MCCK_GUEST);
500 schedule_mcck_handler();
502 irqentry_nmi_exit(regs, irq_state);
504 NOKPROBE_SYMBOL(s390_do_machine_check);
506 static int __init machine_check_init(void)
508 ctl_set_bit(14, 25); /* enable external damage MCH */
509 ctl_set_bit(14, 27); /* enable system recovery MCH */
510 ctl_set_bit(14, 24); /* enable warning MCH */
513 early_initcall(machine_check_init);