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>,
9 * Heiko Carstens <heiko.carstens@de.ibm.com>,
12 #include <linux/kernel_stat.h>
13 #include <linux/init.h>
14 #include <linux/errno.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>
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>
33 #include <linux/kvm_host.h>
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;
43 static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck);
44 static struct kmem_cache *mcesa_cache;
45 static unsigned long mcesa_origin_lc;
47 static inline int nmi_needs_mcesa(void)
49 return MACHINE_HAS_VX || MACHINE_HAS_GS;
52 static inline unsigned long nmi_get_mcesa_size(void)
55 return MCESA_MAX_SIZE;
56 return MCESA_MIN_SIZE;
60 * The initial machine check extended save area for the boot CPU.
61 * It will be replaced on the boot CPU reinit with an allocated
62 * structure. The structure is required for machine check happening
63 * early in the boot process.
65 static struct mcesa boot_mcesa __initdata __aligned(MCESA_MAX_SIZE);
67 void __init nmi_alloc_mcesa_early(u64 *mcesad)
69 if (!nmi_needs_mcesa())
71 *mcesad = __pa(&boot_mcesa);
73 *mcesad |= ilog2(MCESA_MAX_SIZE);
76 static void __init nmi_alloc_cache(void)
80 if (!nmi_needs_mcesa())
82 size = nmi_get_mcesa_size();
83 if (size > MCESA_MIN_SIZE)
84 mcesa_origin_lc = ilog2(size);
85 /* create slab cache for the machine-check-extended-save-areas */
86 mcesa_cache = kmem_cache_create("nmi_save_areas", size, size, 0, NULL);
88 panic("Couldn't create nmi save area cache");
91 int __ref nmi_alloc_mcesa(u64 *mcesad)
96 if (!nmi_needs_mcesa())
100 origin = (unsigned long) kmem_cache_alloc(mcesa_cache, GFP_KERNEL);
103 /* The pointer is stored with mcesa_bits ORed in */
104 kmemleak_not_leak((void *) origin);
105 *mcesad = __pa(origin) | mcesa_origin_lc;
109 void nmi_free_mcesa(u64 *mcesad)
111 if (!nmi_needs_mcesa())
113 kmem_cache_free(mcesa_cache, __va(*mcesad & MCESA_ORIGIN_MASK));
116 static notrace void s390_handle_damage(void)
118 smp_emergency_stop();
122 NOKPROBE_SYMBOL(s390_handle_damage);
125 * Main machine check handler function. Will be called with interrupts disabled
126 * and machine checks enabled.
128 void __s390_handle_mcck(void)
130 struct mcck_struct mcck;
133 * Disable machine checks and get the current state of accumulated
134 * machine checks. Afterwards delete the old state and enable machine
137 local_mcck_disable();
138 mcck = *this_cpu_ptr(&cpu_mcck);
139 memset(this_cpu_ptr(&cpu_mcck), 0, sizeof(mcck));
142 if (mcck.channel_report)
143 crw_handle_channel_report();
145 * A warning may remain for a prolonged period on the bare iron.
146 * (actually until the machine is powered off, or the problem is gone)
147 * So we just stop listening for the WARNING MCH and avoid continuously
148 * being interrupted. One caveat is however, that we must do this per
149 * processor and cannot use the smp version of ctl_clear_bit().
150 * On VM we only get one interrupt per virtally presented machinecheck.
151 * Though one suffices, we may get one interrupt per (virtual) cpu.
153 if (mcck.warning) { /* WARNING pending ? */
154 static int mchchk_wng_posted = 0;
156 /* Use single cpu clear, as we cannot handle smp here. */
157 __ctl_clear_bit(14, 24); /* Disable WARNING MCH */
158 if (xchg(&mchchk_wng_posted, 1) == 0)
159 kill_cad_pid(SIGPWR, 1);
163 if (mcck.kill_task) {
165 printk(KERN_EMERG "mcck: Terminating task because of machine "
166 "malfunction (code 0x%016lx).\n", mcck.mcck_code);
167 printk(KERN_EMERG "mcck: task: %s, pid: %d.\n",
168 current->comm, current->pid);
169 make_task_dead(SIGSEGV);
173 void noinstr s390_handle_mcck(void)
175 trace_hardirqs_off();
176 __s390_handle_mcck();
180 * returns 0 if all required registers are available
181 * returns 1 otherwise
183 static int notrace s390_validate_registers(union mci mci, int umode)
196 * General purpose registers couldn't be restored and have
197 * unknown contents. Stop system or terminate process.
200 s390_handle_damage();
205 * Floating point registers can't be restored. If the
206 * kernel currently uses floating point registers the
207 * system is stopped. If the process has its floating
208 * pointer registers loaded it is terminated.
210 if (S390_lowcore.fpu_flags & KERNEL_VXR_V0V7)
211 s390_handle_damage();
212 if (!test_cpu_flag(CIF_FPU))
215 fpt_save_area = &S390_lowcore.floating_pt_save_area;
218 * Floating point control register can't be restored.
219 * If the kernel currently uses the floating pointer
220 * registers and needs the FPC register the system is
221 * stopped. If the process has its floating pointer
222 * registers loaded it is terminated. Otherwise the
223 * FPC is just validated.
225 if (S390_lowcore.fpu_flags & KERNEL_FPC)
226 s390_handle_damage();
231 if (!test_cpu_flag(CIF_FPU))
237 : "Q" (S390_lowcore.fpt_creg_save_area));
240 mcesa = __va(S390_lowcore.mcesad & MCESA_ORIGIN_MASK);
241 if (!MACHINE_HAS_VX) {
242 /* Validate floating point registers */
261 : "a" (fpt_save_area)
264 /* Validate vector registers */
269 * Vector registers can't be restored. If the kernel
270 * currently uses vector registers the system is
271 * stopped. If the process has its vector registers
272 * loaded it is terminated. Otherwise just validate
275 if (S390_lowcore.fpu_flags & KERNEL_VXR)
276 s390_handle_damage();
277 if (!test_cpu_flag(CIF_FPU))
280 cr0.val = S390_lowcore.cregs_save_area[0];
281 cr0.afp = cr0.vx = 1;
282 __ctl_load(cr0.val, 0, 0);
285 " .word 0xe70f,0x1000,0x0036\n" /* vlm 0,15,0(1) */
286 " .word 0xe70f,0x1100,0x0c36\n" /* vlm 16,31,256(1) */
288 : "Q" (*(struct vx_array *)mcesa->vector_save_area)
290 __ctl_load(S390_lowcore.cregs_save_area[0], 0, 0);
292 /* Validate access registers */
296 : "a" (&S390_lowcore.access_regs_save_area)
300 * Access registers have unknown contents.
305 /* Validate guarded storage registers */
306 cr2.val = S390_lowcore.cregs_save_area[2];
310 * Guarded storage register can't be restored and
311 * the current processes uses guarded storage.
312 * It has to be terminated.
316 load_gs_cb((struct gs_cb *)mcesa->guarded_storage_save_area);
320 * The getcpu vdso syscall reads CPU number from the programmable
321 * field of the TOD clock. Disregard the TOD programmable register
322 * validity bit and load the CPU number into the TOD programmable
323 * field unconditionally.
325 set_tod_programmable_field(raw_smp_processor_id());
326 /* Validate clock comparator register */
327 set_clock_comparator(S390_lowcore.clock_comparator);
329 if (!mci.ms || !mci.pm || !mci.ia)
334 NOKPROBE_SYMBOL(s390_validate_registers);
337 * Backup the guest's machine check info to its description block
339 static void notrace s390_backup_mcck_info(struct pt_regs *regs)
341 struct mcck_volatile_info *mcck_backup;
342 struct sie_page *sie_page;
344 /* r14 contains the sie block, which was set in sie64a */
345 struct kvm_s390_sie_block *sie_block =
346 (struct kvm_s390_sie_block *) regs->gprs[14];
348 if (sie_block == NULL)
349 /* Something's seriously wrong, stop system. */
350 s390_handle_damage();
352 sie_page = container_of(sie_block, struct sie_page, sie_block);
353 mcck_backup = &sie_page->mcck_info;
354 mcck_backup->mcic = S390_lowcore.mcck_interruption_code &
355 ~(MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE);
356 mcck_backup->ext_damage_code = S390_lowcore.external_damage_code;
357 mcck_backup->failing_storage_address
358 = S390_lowcore.failing_storage_address;
360 NOKPROBE_SYMBOL(s390_backup_mcck_info);
362 #define MAX_IPD_COUNT 29
363 #define MAX_IPD_TIME (5 * 60 * USEC_PER_SEC) /* 5 minutes */
365 #define ED_STP_ISLAND 6 /* External damage STP island check */
366 #define ED_STP_SYNC 7 /* External damage STP sync check */
368 #define MCCK_CODE_NO_GUEST (MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE)
371 * machine check handler.
373 int notrace s390_do_machine_check(struct pt_regs *regs)
375 static int ipd_count;
376 static DEFINE_SPINLOCK(ipd_lock);
377 static unsigned long long last_ipd;
378 struct mcck_struct *mcck;
379 unsigned long long tmp;
381 unsigned long mcck_dam_code;
382 int mcck_pending = 0;
388 inc_irq_stat(NMI_NMI);
389 mci.val = S390_lowcore.mcck_interruption_code;
390 mcck = this_cpu_ptr(&cpu_mcck);
393 * Reinject the instruction processing damages' machine checks
394 * including Delayed Access Exception into the guest
395 * instead of damaging the host if they happen in the guest.
397 if (mci.pd && !test_cpu_flag(CIF_MCCK_GUEST)) {
399 /* Processing backup -> verify if we can survive this */
400 u64 z_mcic, o_mcic, t_mcic;
401 z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29);
402 o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
403 1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
404 1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 |
408 if (((t_mcic & z_mcic) != 0) ||
409 ((t_mcic & o_mcic) != o_mcic)) {
410 s390_handle_damage();
414 * Nullifying exigent condition, therefore we might
415 * retry this instruction.
417 spin_lock(&ipd_lock);
418 tmp = get_tod_clock();
419 if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME)
424 if (ipd_count == MAX_IPD_COUNT)
425 s390_handle_damage();
426 spin_unlock(&ipd_lock);
428 /* Processing damage -> stopping machine */
429 s390_handle_damage();
432 if (s390_validate_registers(mci, user_mode(regs))) {
434 * Couldn't restore all register contents for the
435 * user space process -> mark task for termination.
438 mcck->mcck_code = mci.val;
443 * Backup the machine check's info if it happens when the guest
446 if (test_cpu_flag(CIF_MCCK_GUEST))
447 s390_backup_mcck_info(regs);
450 /* Timing facility damage */
451 s390_handle_damage();
453 if (mci.ed && mci.ec) {
454 /* External damage */
455 if (S390_lowcore.external_damage_code & (1U << ED_STP_SYNC))
456 mcck->stp_queue |= stp_sync_check();
457 if (S390_lowcore.external_damage_code & (1U << ED_STP_ISLAND))
458 mcck->stp_queue |= stp_island_check();
463 /* Channel report word pending */
464 mcck->channel_report = 1;
468 /* Warning pending */
474 * If there are only Channel Report Pending and External Damage
475 * machine checks, they will not be reinjected into the guest
476 * because they refer to host conditions only.
478 mcck_dam_code = (mci.val & MCIC_SUBCLASS_MASK);
479 if (test_cpu_flag(CIF_MCCK_GUEST) &&
480 (mcck_dam_code & MCCK_CODE_NO_GUEST) != mcck_dam_code) {
481 /* Set exit reason code for host's later handling */
482 *((long *)(regs->gprs[15] + __SF_SIE_REASON)) = -EINTR;
484 clear_cpu_flag(CIF_MCCK_GUEST);
486 if (user_mode(regs) && mcck_pending) {
492 schedule_mcck_handler();
497 NOKPROBE_SYMBOL(s390_do_machine_check);
499 static int __init machine_check_init(void)
501 ctl_set_bit(14, 25); /* enable external damage MCH */
502 ctl_set_bit(14, 27); /* enable system recovery MCH */
503 ctl_set_bit(14, 24); /* enable warning MCH */
506 early_initcall(machine_check_init);