/* * drivers/s390/s390mach.c * S/390 machine check handler * * S390 version * Copyright (C) 2000 IBM Deutschland Entwicklung GmbH, IBM Corporation * Author(s): Ingo Adlung (adlung@de.ibm.com) * Martin Schwidefsky (schwidefsky@de.ibm.com) */ #include <linux/config.h> #include <linux/init.h> #include <linux/sched.h> #include <linux/errno.h> #include <linux/workqueue.h> #include <asm/lowcore.h> #include "s390mach.h" #define DBG printk // #define DBG(args,...) do {} while (0); static struct semaphore m_sem; extern int css_process_crw(int); extern int chsc_process_crw(void); extern int chp_process_crw(int, int); extern void css_reiterate_subchannels(void); extern struct workqueue_struct *slow_path_wq; extern struct work_struct slow_path_work; static NORET_TYPE void s390_handle_damage(char *msg) { #ifdef CONFIG_SMP smp_send_stop(); #endif disabled_wait((unsigned long) __builtin_return_address(0)); for(;;); } /* * Retrieve CRWs and call function to handle event. * * Note : we currently process CRWs for io and chsc subchannels only */ static int s390_collect_crw_info(void *param) { struct crw crw; int ccode, ret, slow; struct semaphore *sem; sem = (struct semaphore *)param; /* Set a nice name. */ daemonize("kmcheck"); repeat: down_interruptible(sem); slow = 0; while (1) { ccode = stcrw(&crw); if (ccode != 0) break; DBG(KERN_DEBUG "crw_info : CRW reports slct=%d, oflw=%d, " "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n", crw.slct, crw.oflw, crw.chn, crw.rsc, crw.anc, crw.erc, crw.rsid); /* Check for overflows. */ if (crw.oflw) { pr_debug("%s: crw overflow detected!\n", __FUNCTION__); css_reiterate_subchannels(); slow = 1; continue; } switch (crw.rsc) { case CRW_RSC_SCH: pr_debug("source is subchannel %04X\n", crw.rsid); ret = css_process_crw (crw.rsid); if (ret == -EAGAIN) slow = 1; break; case CRW_RSC_MONITOR: pr_debug("source is monitoring facility\n"); break; case CRW_RSC_CPATH: pr_debug("source is channel path %02X\n", crw.rsid); switch (crw.erc) { case CRW_ERC_IPARM: /* Path has come. */ ret = chp_process_crw(crw.rsid, 1); break; case CRW_ERC_PERRI: /* Path has gone. */ case CRW_ERC_PERRN: ret = chp_process_crw(crw.rsid, 0); break; default: pr_debug("Don't know how to handle erc=%x\n", crw.erc); ret = 0; } if (ret == -EAGAIN) slow = 1; break; case CRW_RSC_CONFIG: pr_debug("source is configuration-alert facility\n"); break; case CRW_RSC_CSS: pr_debug("source is channel subsystem\n"); ret = chsc_process_crw(); if (ret == -EAGAIN) slow = 1; break; default: pr_debug("unknown source\n"); break; } } if (slow) queue_work(slow_path_wq, &slow_path_work); goto repeat; return 0; } struct mcck_struct { int kill_task; int channel_report; int warning; unsigned long long mcck_code; }; static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck); /* * 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 = __get_cpu_var(cpu_mcck); memset(&__get_cpu_var(cpu_mcck), 0, sizeof(struct mcck_struct)); clear_thread_flag(TIF_MCCK_PENDING); local_mcck_enable(); local_irq_restore(flags); if (mcck.channel_report) up(&m_sem); #ifdef CONFIG_MACHCHK_WARNING /* * The warning may remain for a prolonged period on the bare iron. * (actually till the machine is powered off, or until the problem is gone) * So we just stop listening for the WARNING MCH and prevent 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) processor. */ if (mcck.warning) { /* WARNING pending ? */ static int mchchk_wng_posted = 0; /* * Use single machine clear, as we cannot handle smp right now */ __ctl_clear_bit(14, 24); /* Disable WARNING MCH */ if (xchg(&mchchk_wng_posted, 1) == 0) kill_proc(1, SIGPWR, 1); } #endif if (mcck.kill_task) { local_irq_enable(); printk(KERN_EMERG "mcck: Terminating task because of machine " "malfunction (code 0x%016llx).\n", mcck.mcck_code); printk(KERN_EMERG "mcck: task: %s, pid: %d.\n", current->comm, current->pid); do_exit(SIGSEGV); } } /* * returns 0 if all registers could be validated * returns 1 otherwise */ static int s390_revalidate_registers(struct mci *mci) { int kill_task; u64 tmpclock; u64 zero; void *fpt_save_area, *fpt_creg_save_area; kill_task = 0; zero = 0; /* General purpose registers */ if (!mci->gr) /* * General purpose registers couldn't be restored and have * unknown contents. Process needs to be terminated. */ kill_task = 1; /* Revalidate floating point registers */ if (!mci->fp) /* * Floating point registers can't be restored and * therefore the process needs to be terminated. */ kill_task = 1; #ifndef __s390x__ asm volatile("ld 0,0(%0)\n" "ld 2,8(%0)\n" "ld 4,16(%0)\n" "ld 6,24(%0)" : : "a" (&S390_lowcore.floating_pt_save_area)); #endif if (MACHINE_HAS_IEEE) { #ifdef __s390x__ fpt_save_area = &S390_lowcore.floating_pt_save_area; fpt_creg_save_area = &S390_lowcore.fpt_creg_save_area; #else fpt_save_area = (void *) S390_lowcore.extended_save_area_addr; fpt_creg_save_area = fpt_save_area+128; #endif /* Floating point control register */ if (!mci->fc) { /* * Floating point control register can't be restored. * Task will be terminated. */ asm volatile ("lfpc 0(%0)" : : "a" (&zero), "m" (zero)); kill_task = 1; } else asm volatile ( "lfpc 0(%0)" : : "a" (fpt_creg_save_area)); 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)); } /* Revalidate 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; /* Revalidate control registers */ if (!mci->cr) /* * Control registers have unknown contents. * Can't recover and therefore stopping machine. */ s390_handle_damage("invalid control registers."); else #ifdef __s390x__ asm volatile("lctlg 0,15,0(%0)" : : "a" (&S390_lowcore.cregs_save_area)); #else asm volatile("lctl 0,15,0(%0)" : : "a" (&S390_lowcore.cregs_save_area)); #endif /* * We don't even try to revalidate the TOD register, since we simply * can't write something sensible into that register. */ #ifdef __s390x__ /* * See if we can revalidate 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"); #endif /* Revalidate clock comparator register */ asm volatile ("stck 0(%1)\n" "sckc 0(%1)" : "=m" (tmpclock) : "a" (&(tmpclock)) : "cc", "memory"); /* 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("old psw invalid."); if (!mci->ms || !mci->pm || !mci->ia) kill_task = 1; return kill_task; } /* * machine check handler. */ void s390_do_machine_check(struct pt_regs *regs) { struct mci *mci; struct mcck_struct *mcck; int umode; mci = (struct mci *) &S390_lowcore.mcck_interruption_code; mcck = &__get_cpu_var(cpu_mcck); umode = user_mode(regs); if (mci->sd) /* System damage -> stopping machine */ s390_handle_damage("received system damage machine check."); if (mci->pd) { if (mci->b) { /* Processing backup -> verify if we can survive this */ u64 z_mcic, o_mcic, t_mcic; #ifdef __s390x__ 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); #else z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<57 | 1ULL<<50 | 1ULL<<29); o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 | 1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 | 1ULL<<30 | 1ULL<<20 | 1ULL<<17 | 1ULL<<16); #endif t_mcic = *(u64 *)mci; if (((t_mcic & z_mcic) != 0) || ((t_mcic & o_mcic) != o_mcic)) { s390_handle_damage("processing backup machine " "check with damage."); } if (!umode) s390_handle_damage("processing backup machine " "check in kernel mode."); mcck->kill_task = 1; mcck->mcck_code = *(unsigned long long *) mci; } else { /* Processing damage -> stopping machine */ s390_handle_damage("received instruction processing " "damage machine check."); } } if (s390_revalidate_registers(mci)) { if (umode) { /* * Couldn't restore all register contents while in * user mode -> mark task for termination. */ mcck->kill_task = 1; mcck->mcck_code = *(unsigned long long *) mci; set_thread_flag(TIF_MCCK_PENDING); } else /* * Couldn't restore all register contents while in * kernel mode -> stopping machine. */ s390_handle_damage("unable to revalidate registers."); } if (mci->se) /* Storage error uncorrected */ s390_handle_damage("received storage error uncorrected " "machine check."); if (mci->ke) /* Storage key-error uncorrected */ s390_handle_damage("received storage key-error uncorrected " "machine check."); if (mci->ds && mci->fa) /* Storage degradation */ s390_handle_damage("received storage degradation machine " "check."); if (mci->cp) { /* Channel report word pending */ mcck->channel_report = 1; set_thread_flag(TIF_MCCK_PENDING); } if (mci->w) { /* Warning pending */ mcck->warning = 1; set_thread_flag(TIF_MCCK_PENDING); } } /* * s390_init_machine_check * * initialize machine check handling */ static int machine_check_init(void) { init_MUTEX_LOCKED(&m_sem); ctl_clear_bit(14, 25); /* disable external damage MCH */ ctl_set_bit(14, 27); /* enable system recovery MCH */ #ifdef CONFIG_MACHCHK_WARNING ctl_set_bit(14, 24); /* enable warning MCH */ #endif return 0; } /* * Initialize the machine check handler really early to be able to * catch all machine checks that happen during boot */ arch_initcall(machine_check_init); /* * Machine checks for the channel subsystem must be enabled * after the channel subsystem is initialized */ static int __init machine_check_crw_init (void) { kernel_thread(s390_collect_crw_info, &m_sem, CLONE_FS|CLONE_FILES); ctl_set_bit(14, 28); /* enable channel report MCH */ return 0; } device_initcall (machine_check_crw_init);