| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Machine check handler |
| * |
| * Copyright IBM Corp. 2000, 2009 |
| * Author(s): Ingo Adlung <adlung@de.ibm.com>, |
| * Martin Schwidefsky <schwidefsky@de.ibm.com>, |
| * Cornelia Huck <cornelia.huck@de.ibm.com>, |
| */ |
| |
| #include <linux/kernel_stat.h> |
| #include <linux/init.h> |
| #include <linux/errno.h> |
| #include <linux/entry-common.h> |
| #include <linux/hardirq.h> |
| #include <linux/log2.h> |
| #include <linux/kprobes.h> |
| #include <linux/kmemleak.h> |
| #include <linux/time.h> |
| #include <linux/module.h> |
| #include <linux/sched/signal.h> |
| #include <linux/kvm_host.h> |
| #include <linux/export.h> |
| #include <asm/lowcore.h> |
| #include <asm/ctlreg.h> |
| #include <asm/smp.h> |
| #include <asm/stp.h> |
| #include <asm/cputime.h> |
| #include <asm/nmi.h> |
| #include <asm/crw.h> |
| #include <asm/switch_to.h> |
| #include <asm/asm-offsets.h> |
| #include <asm/pai.h> |
| #include <asm/vx-insn.h> |
| #include <asm/fpu/api.h> |
| |
| struct mcck_struct { |
| unsigned int kill_task : 1; |
| unsigned int channel_report : 1; |
| unsigned int warning : 1; |
| unsigned int stp_queue : 1; |
| unsigned long mcck_code; |
| }; |
| |
| static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck); |
| |
| static inline int nmi_needs_mcesa(void) |
| { |
| return cpu_has_vx() || MACHINE_HAS_GS; |
| } |
| |
| /* |
| * The initial machine check extended save area for the boot CPU. |
| * It will be replaced on the boot CPU reinit with an allocated |
| * structure. The structure is required for machine check happening |
| * early in the boot process. |
| */ |
| static struct mcesa boot_mcesa __aligned(MCESA_MAX_SIZE); |
| |
| void __init nmi_alloc_mcesa_early(u64 *mcesad) |
| { |
| if (!nmi_needs_mcesa()) |
| return; |
| *mcesad = __pa(&boot_mcesa); |
| if (MACHINE_HAS_GS) |
| *mcesad |= ilog2(MCESA_MAX_SIZE); |
| } |
| |
| int nmi_alloc_mcesa(u64 *mcesad) |
| { |
| unsigned long size; |
| void *origin; |
| |
| *mcesad = 0; |
| if (!nmi_needs_mcesa()) |
| return 0; |
| size = MACHINE_HAS_GS ? MCESA_MAX_SIZE : MCESA_MIN_SIZE; |
| origin = kmalloc(size, GFP_KERNEL); |
| if (!origin) |
| return -ENOMEM; |
| /* The pointer is stored with mcesa_bits ORed in */ |
| kmemleak_not_leak(origin); |
| *mcesad = __pa(origin); |
| if (MACHINE_HAS_GS) |
| *mcesad |= ilog2(MCESA_MAX_SIZE); |
| return 0; |
| } |
| |
| void nmi_free_mcesa(u64 *mcesad) |
| { |
| if (!nmi_needs_mcesa()) |
| return; |
| kfree(__va(*mcesad & MCESA_ORIGIN_MASK)); |
| } |
| |
| static __always_inline char *nmi_puts(char *dest, const char *src) |
| { |
| while (*src) |
| *dest++ = *src++; |
| *dest = 0; |
| return dest; |
| } |
| |
| static __always_inline char *u64_to_hex(char *dest, u64 val) |
| { |
| int i, num; |
| |
| for (i = 1; i <= 16; i++) { |
| num = (val >> (64 - 4 * i)) & 0xf; |
| if (num >= 10) |
| *dest++ = 'A' + num - 10; |
| else |
| *dest++ = '0' + num; |
| } |
| *dest = 0; |
| return dest; |
| } |
| |
| static notrace void s390_handle_damage(void) |
| { |
| union ctlreg0 cr0, cr0_new; |
| char message[100]; |
| psw_t psw_save; |
| char *ptr; |
| |
| smp_emergency_stop(); |
| diag_amode31_ops.diag308_reset(); |
| ptr = nmi_puts(message, "System stopped due to unrecoverable machine check, code: 0x"); |
| u64_to_hex(ptr, S390_lowcore.mcck_interruption_code); |
| |
| /* |
| * Disable low address protection and make machine check new PSW a |
| * disabled wait PSW. Any additional machine check cannot be handled. |
| */ |
| local_ctl_store(0, &cr0.reg); |
| cr0_new = cr0; |
| cr0_new.lap = 0; |
| local_ctl_load(0, &cr0_new.reg); |
| psw_save = S390_lowcore.mcck_new_psw; |
| psw_bits(S390_lowcore.mcck_new_psw).io = 0; |
| psw_bits(S390_lowcore.mcck_new_psw).ext = 0; |
| psw_bits(S390_lowcore.mcck_new_psw).wait = 1; |
| sclp_emergency_printk(message); |
| |
| /* |
| * Restore machine check new PSW and control register 0 to original |
| * values. This makes possible system dump analysis easier. |
| */ |
| S390_lowcore.mcck_new_psw = psw_save; |
| local_ctl_load(0, &cr0.reg); |
| disabled_wait(); |
| while (1); |
| } |
| NOKPROBE_SYMBOL(s390_handle_damage); |
| |
| /* |
| * Main machine check handler function. Will be called with interrupts disabled |
| * and machine checks enabled. |
| */ |
| void s390_handle_mcck(void) |
| { |
| struct mcck_struct mcck; |
| unsigned long mflags; |
| |
| /* |
| * Disable machine checks and get the current state of accumulated |
| * machine checks. Afterwards delete the old state and enable machine |
| * checks again. |
| */ |
| local_mcck_save(mflags); |
| mcck = *this_cpu_ptr(&cpu_mcck); |
| memset(this_cpu_ptr(&cpu_mcck), 0, sizeof(mcck)); |
| local_mcck_restore(mflags); |
| |
| if (mcck.channel_report) |
| crw_handle_channel_report(); |
| /* |
| * A warning may remain for a prolonged period on the bare iron. |
| * (actually until the machine is powered off, or the problem is gone) |
| * So we just stop listening for the WARNING MCH and avoid continuously |
| * being interrupted. One caveat is however, that we must do this per |
| * processor and cannot use the smp version of ctl_clear_bit(). |
| * On VM we only get one interrupt per virtally presented machinecheck. |
| * Though one suffices, we may get one interrupt per (virtual) cpu. |
| */ |
| if (mcck.warning) { /* WARNING pending ? */ |
| static int mchchk_wng_posted = 0; |
| |
| /* Use single cpu clear, as we cannot handle smp here. */ |
| local_ctl_clear_bit(14, CR14_WARNING_SUBMASK_BIT); |
| if (xchg(&mchchk_wng_posted, 1) == 0) |
| kill_cad_pid(SIGPWR, 1); |
| } |
| if (mcck.stp_queue) |
| stp_queue_work(); |
| if (mcck.kill_task) { |
| printk(KERN_EMERG "mcck: Terminating task because of machine " |
| "malfunction (code 0x%016lx).\n", mcck.mcck_code); |
| printk(KERN_EMERG "mcck: task: %s, pid: %d.\n", |
| current->comm, current->pid); |
| if (is_global_init(current)) |
| panic("mcck: Attempting to kill init!\n"); |
| do_send_sig_info(SIGKILL, SEND_SIG_PRIV, current, PIDTYPE_PID); |
| } |
| } |
| |
| /* |
| * returns 0 if register contents could be validated |
| * returns 1 otherwise |
| */ |
| static int notrace s390_validate_registers(union mci mci) |
| { |
| struct mcesa *mcesa; |
| void *fpt_save_area; |
| union ctlreg2 cr2; |
| int kill_task; |
| u64 zero; |
| |
| kill_task = 0; |
| zero = 0; |
| |
| if (!mci.gr || !mci.fp) |
| kill_task = 1; |
| fpt_save_area = &S390_lowcore.floating_pt_save_area; |
| if (!mci.fc) { |
| kill_task = 1; |
| asm volatile( |
| " lfpc %0\n" |
| : |
| : "Q" (zero)); |
| } else { |
| asm volatile( |
| " lfpc %0\n" |
| : |
| : "Q" (S390_lowcore.fpt_creg_save_area)); |
| } |
| |
| mcesa = __va(S390_lowcore.mcesad & MCESA_ORIGIN_MASK); |
| if (!cpu_has_vx()) { |
| /* Validate floating point registers */ |
| asm volatile( |
| " ld 0,0(%0)\n" |
| " ld 1,8(%0)\n" |
| " ld 2,16(%0)\n" |
| " ld 3,24(%0)\n" |
| " ld 4,32(%0)\n" |
| " ld 5,40(%0)\n" |
| " ld 6,48(%0)\n" |
| " ld 7,56(%0)\n" |
| " ld 8,64(%0)\n" |
| " ld 9,72(%0)\n" |
| " ld 10,80(%0)\n" |
| " ld 11,88(%0)\n" |
| " ld 12,96(%0)\n" |
| " ld 13,104(%0)\n" |
| " ld 14,112(%0)\n" |
| " ld 15,120(%0)\n" |
| : |
| : "a" (fpt_save_area) |
| : "memory"); |
| } else { |
| /* Validate vector registers */ |
| union ctlreg0 cr0; |
| |
| /* |
| * The vector validity must only be checked if not running a |
| * KVM guest. For KVM guests the machine check is forwarded by |
| * KVM and it is the responsibility of the guest to take |
| * appropriate actions. The host vector or FPU values have been |
| * saved by KVM and will be restored by KVM. |
| */ |
| if (!mci.vr && !test_cpu_flag(CIF_MCCK_GUEST)) |
| kill_task = 1; |
| cr0.reg = S390_lowcore.cregs_save_area[0]; |
| cr0.afp = cr0.vx = 1; |
| local_ctl_load(0, &cr0.reg); |
| asm volatile( |
| " la 1,%0\n" |
| " VLM 0,15,0,1\n" |
| " VLM 16,31,256,1\n" |
| : |
| : "Q" (*(struct vx_array *)mcesa->vector_save_area) |
| : "1"); |
| local_ctl_load(0, &S390_lowcore.cregs_save_area[0]); |
| } |
| /* Validate access registers */ |
| asm volatile( |
| " lam 0,15,0(%0)\n" |
| : |
| : "a" (&S390_lowcore.access_regs_save_area) |
| : "memory"); |
| if (!mci.ar) |
| kill_task = 1; |
| /* Validate guarded storage registers */ |
| cr2.reg = S390_lowcore.cregs_save_area[2]; |
| if (cr2.gse) { |
| if (!mci.gs) { |
| /* |
| * 2 cases: |
| * - machine check in kernel or userspace |
| * - machine check while running SIE (KVM guest) |
| * For kernel or userspace the userspace values of |
| * guarded storage control can not be recreated, the |
| * process must be terminated. |
| * For SIE the guest values of guarded storage can not |
| * be recreated. This is either due to a bug or due to |
| * GS being disabled in the guest. The guest will be |
| * notified by KVM code and the guests machine check |
| * handling must take care of this. The host values |
| * are saved by KVM and are not affected. |
| */ |
| if (!test_cpu_flag(CIF_MCCK_GUEST)) |
| kill_task = 1; |
| } else { |
| load_gs_cb((struct gs_cb *)mcesa->guarded_storage_save_area); |
| } |
| } |
| /* |
| * The getcpu vdso syscall reads CPU number from the programmable |
| * field of the TOD clock. Disregard the TOD programmable register |
| * validity bit and load the CPU number into the TOD programmable |
| * field unconditionally. |
| */ |
| set_tod_programmable_field(raw_smp_processor_id()); |
| /* Validate clock comparator register */ |
| set_clock_comparator(S390_lowcore.clock_comparator); |
| |
| if (!mci.ms || !mci.pm || !mci.ia) |
| kill_task = 1; |
| |
| return kill_task; |
| } |
| NOKPROBE_SYMBOL(s390_validate_registers); |
| |
| /* |
| * Backup the guest's machine check info to its description block |
| */ |
| static void notrace s390_backup_mcck_info(struct pt_regs *regs) |
| { |
| struct mcck_volatile_info *mcck_backup; |
| struct sie_page *sie_page; |
| |
| /* r14 contains the sie block, which was set in sie64a */ |
| struct kvm_s390_sie_block *sie_block = phys_to_virt(regs->gprs[14]); |
| |
| if (sie_block == NULL) |
| /* Something's seriously wrong, stop system. */ |
| s390_handle_damage(); |
| |
| sie_page = container_of(sie_block, struct sie_page, sie_block); |
| mcck_backup = &sie_page->mcck_info; |
| mcck_backup->mcic = S390_lowcore.mcck_interruption_code & |
| ~(MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE); |
| mcck_backup->ext_damage_code = S390_lowcore.external_damage_code; |
| mcck_backup->failing_storage_address |
| = S390_lowcore.failing_storage_address; |
| } |
| NOKPROBE_SYMBOL(s390_backup_mcck_info); |
| |
| #define MAX_IPD_COUNT 29 |
| #define MAX_IPD_TIME (5 * 60 * USEC_PER_SEC) /* 5 minutes */ |
| |
| #define ED_STP_ISLAND 6 /* External damage STP island check */ |
| #define ED_STP_SYNC 7 /* External damage STP sync check */ |
| |
| #define MCCK_CODE_NO_GUEST (MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE) |
| |
| /* |
| * machine check handler. |
| */ |
| void notrace s390_do_machine_check(struct pt_regs *regs) |
| { |
| static int ipd_count; |
| static DEFINE_SPINLOCK(ipd_lock); |
| static unsigned long long last_ipd; |
| struct mcck_struct *mcck; |
| unsigned long long tmp; |
| irqentry_state_t irq_state; |
| union mci mci; |
| unsigned long mcck_dam_code; |
| int mcck_pending = 0; |
| |
| irq_state = irqentry_nmi_enter(regs); |
| |
| if (user_mode(regs)) |
| update_timer_mcck(); |
| inc_irq_stat(NMI_NMI); |
| mci.val = S390_lowcore.mcck_interruption_code; |
| mcck = this_cpu_ptr(&cpu_mcck); |
| |
| /* |
| * Reinject the instruction processing damages' machine checks |
| * including Delayed Access Exception into the guest |
| * instead of damaging the host if they happen in the guest. |
| */ |
| if (mci.pd && !test_cpu_flag(CIF_MCCK_GUEST)) { |
| if (mci.b) { |
| /* Processing backup -> verify if we can survive this */ |
| u64 z_mcic, o_mcic, t_mcic; |
| z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29); |
| o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 | |
| 1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 | |
| 1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 | |
| 1ULL<<16); |
| t_mcic = mci.val; |
| |
| if (((t_mcic & z_mcic) != 0) || |
| ((t_mcic & o_mcic) != o_mcic)) { |
| s390_handle_damage(); |
| } |
| |
| /* |
| * Nullifying exigent condition, therefore we might |
| * retry this instruction. |
| */ |
| spin_lock(&ipd_lock); |
| tmp = get_tod_clock(); |
| if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME) |
| ipd_count++; |
| else |
| ipd_count = 1; |
| last_ipd = tmp; |
| if (ipd_count == MAX_IPD_COUNT) |
| s390_handle_damage(); |
| spin_unlock(&ipd_lock); |
| } else { |
| /* Processing damage -> stopping machine */ |
| s390_handle_damage(); |
| } |
| } |
| if (s390_validate_registers(mci)) { |
| if (!user_mode(regs)) |
| s390_handle_damage(); |
| /* |
| * Couldn't restore all register contents for the |
| * user space process -> mark task for termination. |
| */ |
| mcck->kill_task = 1; |
| mcck->mcck_code = mci.val; |
| mcck_pending = 1; |
| } |
| |
| /* |
| * Backup the machine check's info if it happens when the guest |
| * is running. |
| */ |
| if (test_cpu_flag(CIF_MCCK_GUEST)) |
| s390_backup_mcck_info(regs); |
| |
| if (mci.cd) { |
| /* Timing facility damage */ |
| s390_handle_damage(); |
| } |
| if (mci.ed && mci.ec) { |
| /* External damage */ |
| if (S390_lowcore.external_damage_code & (1U << ED_STP_SYNC)) |
| mcck->stp_queue |= stp_sync_check(); |
| if (S390_lowcore.external_damage_code & (1U << ED_STP_ISLAND)) |
| mcck->stp_queue |= stp_island_check(); |
| mcck_pending = 1; |
| } |
| /* |
| * Reinject storage related machine checks into the guest if they |
| * happen when the guest is running. |
| */ |
| if (!test_cpu_flag(CIF_MCCK_GUEST)) { |
| /* Storage error uncorrected */ |
| if (mci.se) |
| s390_handle_damage(); |
| /* Storage key-error uncorrected */ |
| if (mci.ke) |
| s390_handle_damage(); |
| /* Storage degradation */ |
| if (mci.ds && mci.fa) |
| s390_handle_damage(); |
| } |
| if (mci.cp) { |
| /* Channel report word pending */ |
| mcck->channel_report = 1; |
| mcck_pending = 1; |
| } |
| if (mci.w) { |
| /* Warning pending */ |
| mcck->warning = 1; |
| mcck_pending = 1; |
| } |
| |
| /* |
| * If there are only Channel Report Pending and External Damage |
| * machine checks, they will not be reinjected into the guest |
| * because they refer to host conditions only. |
| */ |
| mcck_dam_code = (mci.val & MCIC_SUBCLASS_MASK); |
| if (test_cpu_flag(CIF_MCCK_GUEST) && |
| (mcck_dam_code & MCCK_CODE_NO_GUEST) != mcck_dam_code) { |
| /* Set exit reason code for host's later handling */ |
| *((long *)(regs->gprs[15] + __SF_SIE_REASON)) = -EINTR; |
| } |
| clear_cpu_flag(CIF_MCCK_GUEST); |
| |
| if (mcck_pending) |
| schedule_mcck_handler(); |
| |
| irqentry_nmi_exit(regs, irq_state); |
| } |
| NOKPROBE_SYMBOL(s390_do_machine_check); |
| |
| static int __init machine_check_init(void) |
| { |
| system_ctl_set_bit(14, CR14_EXTERNAL_DAMAGE_SUBMASK_BIT); |
| system_ctl_set_bit(14, CR14_RECOVERY_SUBMASK_BIT); |
| system_ctl_set_bit(14, CR14_WARNING_SUBMASK_BIT); |
| return 0; |
| } |
| early_initcall(machine_check_init); |