+
+ /*
+ * 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;
+
+ lockdep_off();
+
+ 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);
+ }
+ lockdep_on();