summaryrefslogtreecommitdiffstats
path: root/arch/s390/kernel/nmi.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/s390/kernel/nmi.c')
-rw-r--r--arch/s390/kernel/nmi.c376
1 files changed, 376 insertions, 0 deletions
diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
new file mode 100644
index 0000000..4bfdc42
--- /dev/null
+++ b/arch/s390/kernel/nmi.c
@@ -0,0 +1,376 @@
+/*
+ * 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();
+ /*
+ * 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.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 */
+ ctl_set_bit(14, 24); /* enable warning MCH */
+ return 0;
+}
+arch_initcall(machine_check_init);
OpenPOWER on IntegriCloud