[S390] split/move machine check handler code

Split machine check handler code and move it to cio and kernel code
where it belongs to. No functional change.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

3 files changed, 385 insertions, 2 deletions

diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index 33e7aee70513..228e3105ded7 100644
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -22,7 +22,7 @@ CFLAGS_sysinfo.o += -Iinclude/math-emu -Iarch/s390/math-emu -w
 obj-y   :=  bitmap.o traps.o time.o process.o base.o early.o setup.o \
             processor.o sys_s390.o ptrace.o signal.o cpcmd.o ebcdic.o \
             s390_ext.o debug.o irq.o ipl.o dis.o diag.o mem_detect.o \
-            vdso.o vtime.o sysinfo.o
+            vdso.o vtime.o sysinfo.o nmi.o
 
 obj-y   += $(if $(CONFIG_64BIT),entry64.o,entry.o)
 obj-y   += $(if $(CONFIG_64BIT),reipl64.o,reipl.o)
diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
new file mode 100644
index 000000000000..8d50eaf76a60
--- /dev/null
+++ b/arch/s390/kernel/nmi.c
@@ -0,0 +1,383 @@
+/*
+ *   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/init.h>
+#include <linux/errno.h>
+#include <linux/time.h>
+#include <linux/module.h>
+#include <asm/lowcore.h>
+#include <asm/smp.h>
+#include <asm/etr.h>
+#include <asm/cpu.h>
+#include <asm/nmi.h>
+#include <asm/crw.h>
+
+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);
+
+static NORET_TYPE void s390_handle_damage(char *msg)
+{
+        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 = __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)
+                crw_handle_channel_report();
+
+#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_cad_pid(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);
+        }
+}
+EXPORT_SYMBOL_GPL(s390_handle_mcck);
+
+/*
+ * returns 0 if all registers could be validated
+ * returns 1 otherwise
+ */
+static int notrace 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;
+
+        if (!mci->gr) {
+                /*
+                 * General purpose registers couldn't be restored and have
+                 * unknown contents. Process needs to be terminated.
+                 */
+                kill_task = 1;
+        }
+        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
+                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 */
+
+#define ED_STP_ISLAND   6       /* External damage STP island check */
+#define ED_STP_SYNC     7       /* External damage STP sync check */
+#define ED_ETR_SYNC     12      /* External damage ETR sync check */
+#define ED_ETR_SWITCH   13      /* External damage ETR switch to local */
+
+/*
+ * 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;
+        struct mci *mci;
+        int umode;
+
+        lockdep_off();
+        s390_idle_check();
+
+        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->cd) {
+                /* Timing facility damage */
+                s390_handle_damage("TOD clock damaged");
+        }
+        if (mci->ed && mci->ec) {
+                /* External damage */
+                if (S390_lowcore.external_damage_code & (1U << ED_ETR_SYNC))
+                        etr_sync_check();
+                if (S390_lowcore.external_damage_code & (1U << ED_ETR_SWITCH))
+                        etr_switch_to_local();
+                if (S390_lowcore.external_damage_code & (1U << ED_STP_SYNC))
+                        stp_sync_check();
+                if (S390_lowcore.external_damage_code & (1U << ED_STP_ISLAND))
+                        stp_island_check();
+        }
+        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);
+        }
+        lockdep_on();
+}
+
+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 */
+#ifdef CONFIG_MACHCHK_WARNING
+        ctl_set_bit(14, 24);    /* enable warning MCH */
+#endif
+        return 0;
+}
+arch_initcall(machine_check_init);
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index e6b480625cb3..bd616fb31e75 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -39,6 +39,7 @@
 #include <asm/processor.h>
 #include <asm/irq.h>
 #include <asm/timer.h>
+#include <asm/nmi.h>
 #include "entry.h"
 
 asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
@@ -68,7 +69,6 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
         return sf->gprs[8];
 }
 
-extern void s390_handle_mcck(void);
 /*
  * The idle loop on a S390...
  */