| /* |
| * 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>, |
| * Heiko Carstens <heiko.carstens@de.ibm.com>, |
| */ |
| |
| #include <linux/kernel_stat.h> |
| #include <linux/init.h> |
| #include <linux/errno.h> |
| #include <linux/hardirq.h> |
| #include <linux/time.h> |
| #include <linux/module.h> |
| #include <asm/lowcore.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/ctl_reg.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 void s390_handle_damage(void) |
| { |
| smp_send_stop(); |
| disabled_wait((unsigned long) __builtin_return_address(0)); |
| while (1); |
| } |
| |
| /* |
| * Main machine check handler function. Will be called with interrupts enabled |
| * or disabled and machine checks enabled or disabled. |
| */ |
| void s390_handle_mcck(void) |
| { |
| unsigned long flags; |
| struct mcck_struct mcck; |
| |
| /* |
| * Disable machine checks and get the current state of accumulated |
| * machine checks. Afterwards delete the old state and enable machine |
| * checks again. |
| */ |
| local_irq_save(flags); |
| local_mcck_disable(); |
| mcck = *this_cpu_ptr(&cpu_mcck); |
| memset(this_cpu_ptr(&cpu_mcck), 0, sizeof(mcck)); |
| clear_cpu_flag(CIF_MCCK_PENDING); |
| local_mcck_enable(); |
| local_irq_restore(flags); |
| |
| 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. */ |
| __ctl_clear_bit(14, 24); /* Disable WARNING MCH */ |
| if (xchg(&mchchk_wng_posted, 1) == 0) |
| kill_cad_pid(SIGPWR, 1); |
| } |
| if (mcck.stp_queue) |
| stp_queue_work(); |
| if (mcck.kill_task) { |
| local_irq_enable(); |
| 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); |
| do_exit(SIGSEGV); |
| } |
| } |
| EXPORT_SYMBOL_GPL(s390_handle_mcck); |
| |
| /* |
| * returns 0 if all registers could be validated |
| * returns 1 otherwise |
| */ |
| static int notrace s390_validate_registers(union mci mci, int umode) |
| { |
| int kill_task; |
| u64 zero; |
| void *fpt_save_area, *fpt_creg_save_area; |
| |
| kill_task = 0; |
| zero = 0; |
| |
| if (!mci.gr) { |
| /* |
| * General purpose registers couldn't be restored and have |
| * unknown contents. Stop system or terminate process. |
| */ |
| if (!umode) |
| s390_handle_damage(); |
| kill_task = 1; |
| } |
| if (!mci.fp) { |
| /* |
| * Floating point registers can't be restored. If the |
| * kernel currently uses floating point registers the |
| * system is stopped. If the process has its floating |
| * pointer registers loaded it is terminated. |
| * Otherwise just revalidate the registers. |
| */ |
| if (S390_lowcore.fpu_flags & KERNEL_VXR_V0V7) |
| s390_handle_damage(); |
| if (!test_cpu_flag(CIF_FPU)) |
| kill_task = 1; |
| } |
| fpt_save_area = &S390_lowcore.floating_pt_save_area; |
| fpt_creg_save_area = &S390_lowcore.fpt_creg_save_area; |
| if (!mci.fc) { |
| /* |
| * Floating point control register can't be restored. |
| * If the kernel currently uses the floating pointer |
| * registers and needs the FPC register the system is |
| * stopped. If the process has its floating pointer |
| * registers loaded it is terminated. Otherwiese the |
| * FPC is just revalidated. |
| */ |
| if (S390_lowcore.fpu_flags & KERNEL_FPC) |
| s390_handle_damage(); |
| asm volatile("lfpc 0(%0)" : : "a" (&zero), "m" (zero)); |
| if (!test_cpu_flag(CIF_FPU)) |
| kill_task = 1; |
| } else |
| asm volatile("lfpc 0(%0)" : : "a" (fpt_creg_save_area)); |
| |
| if (!MACHINE_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)); |
| } else { |
| /* Validate vector registers */ |
| union ctlreg0 cr0; |
| |
| if (!mci.vr) { |
| /* |
| * Vector registers can't be restored. If the kernel |
| * currently uses vector registers the system is |
| * stopped. If the process has its vector registers |
| * loaded it is terminated. Otherwise just revalidate |
| * the registers. |
| */ |
| if (S390_lowcore.fpu_flags & KERNEL_VXR) |
| s390_handle_damage(); |
| if (!test_cpu_flag(CIF_FPU)) |
| kill_task = 1; |
| } |
| cr0.val = S390_lowcore.cregs_save_area[0]; |
| cr0.afp = cr0.vx = 1; |
| __ctl_load(cr0.val, 0, 0); |
| asm volatile( |
| " la 1,%0\n" |
| " .word 0xe70f,0x1000,0x0036\n" /* vlm 0,15,0(1) */ |
| " .word 0xe70f,0x1100,0x0c36\n" /* vlm 16,31,256(1) */ |
| : : "Q" (*(struct vx_array *) |
| &S390_lowcore.vector_save_area) : "1"); |
| __ctl_load(S390_lowcore.cregs_save_area[0], 0, 0); |
| } |
| /* Validate access registers */ |
| asm volatile( |
| " lam 0,15,0(%0)" |
| : : "a" (&S390_lowcore.access_regs_save_area)); |
| if (!mci.ar) { |
| /* |
| * Access registers have unknown contents. |
| * Terminating task. |
| */ |
| kill_task = 1; |
| } |
| /* Validate control registers */ |
| if (!mci.cr) { |
| /* |
| * Control registers have unknown contents. |
| * Can't recover and therefore stopping machine. |
| */ |
| s390_handle_damage(); |
| } else { |
| asm volatile( |
| " lctlg 0,15,0(%0)" |
| : : "a" (&S390_lowcore.cregs_save_area)); |
| } |
| /* |
| * We don't even try to validate the TOD register, since we simply |
| * can't write something sensible into that register. |
| */ |
| /* |
| * See if we can validate the TOD programmable register with its |
| * old contents (should be zero) otherwise set it to zero. |
| */ |
| if (!mci.pr) |
| asm volatile( |
| " sr 0,0\n" |
| " sckpf" |
| : : : "0", "cc"); |
| else |
| asm volatile( |
| " l 0,0(%0)\n" |
| " sckpf" |
| : : "a" (&S390_lowcore.tod_progreg_save_area) |
| : "0", "cc"); |
| /* Validate clock comparator register */ |
| set_clock_comparator(S390_lowcore.clock_comparator); |
| /* Check if old PSW is valid */ |
| if (!mci.wp) |
| /* |
| * Can't tell if we come from user or kernel mode |
| * -> stopping machine. |
| */ |
| s390_handle_damage(); |
| |
| if (!mci.ms || !mci.pm || !mci.ia) |
| kill_task = 1; |
| |
| return kill_task; |
| } |
| |
| #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 */ |
| |
| /* |
| * 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; |
| union mci mci; |
| |
| nmi_enter(); |
| inc_irq_stat(NMI_NMI); |
| mci.val = S390_lowcore.mcck_interruption_code; |
| mcck = this_cpu_ptr(&cpu_mcck); |
| |
| if (mci.sd) { |
| /* System damage -> stopping machine */ |
| s390_handle_damage(); |
| } |
| if (mci.pd) { |
| 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, user_mode(regs))) { |
| /* |
| * Couldn't restore all register contents for the |
| * user space process -> mark task for termination. |
| */ |
| mcck->kill_task = 1; |
| mcck->mcck_code = mci.val; |
| set_cpu_flag(CIF_MCCK_PENDING); |
| } |
| 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(); |
| if (mcck->stp_queue) |
| set_cpu_flag(CIF_MCCK_PENDING); |
| } |
| if (mci.se) |
| /* Storage error uncorrected */ |
| s390_handle_damage(); |
| if (mci.ke) |
| /* Storage key-error uncorrected */ |
| s390_handle_damage(); |
| if (mci.ds && mci.fa) |
| /* Storage degradation */ |
| s390_handle_damage(); |
| if (mci.cp) { |
| /* Channel report word pending */ |
| mcck->channel_report = 1; |
| set_cpu_flag(CIF_MCCK_PENDING); |
| } |
| if (mci.w) { |
| /* Warning pending */ |
| mcck->warning = 1; |
| set_cpu_flag(CIF_MCCK_PENDING); |
| } |
| nmi_exit(); |
| } |
| |
| static int __init machine_check_init(void) |
| { |
| ctl_set_bit(14, 25); /* enable external damage MCH */ |
| ctl_set_bit(14, 27); /* enable system recovery MCH */ |
| ctl_set_bit(14, 24); /* enable warning MCH */ |
| return 0; |
| } |
| early_initcall(machine_check_init); |