Linux 2.6.17.7

[linux/fpc-iii.git] / drivers / s390 / s390mach.c

/*
 *  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 <linux/time.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, 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[2];
        int ccode, ret, slow;
        struct semaphore *sem;
        unsigned int chain;

        sem = (struct semaphore *)param;
        /* Set a nice name. */
        daemonize("kmcheck");
repeat:
        down_interruptible(sem);
        slow = 0;
        chain = 0;
        while (1) {
                if (unlikely(chain > 1)) {
                        struct crw tmp_crw;

                        printk(KERN_WARNING"%s: Code does not support more "
                               "than two chained crws; please report to "
                               "linux390@de.ibm.com!\n", __FUNCTION__);
                        ccode = stcrw(&tmp_crw);
                        printk(KERN_WARNING"%s: crw reports slct=%d, oflw=%d, "
                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
                               __FUNCTION__, tmp_crw.slct, tmp_crw.oflw,
                               tmp_crw.chn, tmp_crw.rsc, tmp_crw.anc,
                               tmp_crw.erc, tmp_crw.rsid);
                        printk(KERN_WARNING"%s: This was crw number %x in the "
                               "chain\n", __FUNCTION__, chain);
                        if (ccode != 0)
                                break;
                        chain = tmp_crw.chn ? chain + 1 : 0;
                        continue;
                }
                ccode = stcrw(&crw[chain]);
                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[chain].slct, crw[chain].oflw, crw[chain].chn,
                    crw[chain].rsc, crw[chain].anc, crw[chain].erc,
                    crw[chain].rsid);
                /* Check for overflows. */
                if (crw[chain].oflw) {
                        pr_debug("%s: crw overflow detected!\n", __FUNCTION__);
                        css_reiterate_subchannels();
                        chain = 0;
                        slow = 1;
                        continue;
                }
                switch (crw[chain].rsc) {
                case CRW_RSC_SCH:
                        if (crw[0].chn && !chain)
                                break;
                        pr_debug("source is subchannel %04X\n", crw[0].rsid);
                        ret = css_process_crw (crw[0].rsid,
                                               chain ? crw[1].rsid : 0);
                        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[0].rsid);
                        switch (crw[0].erc) {
                        case CRW_ERC_IPARM: /* Path has come. */
                                ret = chp_process_crw(crw[0].rsid, 1);
                                break;
                        case CRW_ERC_PERRI: /* Path has gone. */
                        case CRW_ERC_PERRN:
                                ret = chp_process_crw(crw[0].rsid, 0);
                                break;
                        default:
                                pr_debug("Don't know how to handle erc=%x\n",
                                         crw[0].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;
                }
                /* chain is always 0 or 1 here. */
                chain = crw[chain].chn ? chain + 1 : 0;
        }
        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 CONFIG_64BIT
        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 CONFIG_64BIT
                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 CONFIG_64BIT
                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 CONFIG_64BIT
        /*
         * 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;
}

#define MAX_IPD_COUNT   29
#define MAX_IPD_TIME    (5 * 60 * USEC_PER_SEC) /* 5 minutes */

/*
 * machine check handler.
 */
void
s390_do_machine_check(struct pt_regs *regs)
{
        static DEFINE_SPINLOCK(ipd_lock);
        static unsigned long long last_ipd;
        static int ipd_count;
        unsigned long long tmp;
        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 CONFIG_64BIT
                        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.");
                        }

                        /*
                         * Nullifying exigent condition, therefore we might
                         * retry this instruction.
                         */

                        spin_lock(&ipd_lock);

                        tmp = get_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("too many ipd retries.");

                        spin_unlock(&ipd_lock);
                }
                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);