1 files changed, 287 insertions, 34 deletions

diff --git a/drivers/s390/s390mach.c b/drivers/s390/s390mach.c
index ffa996c8a908..5bb255e02acc 100644
--- a/drivers/s390/s390mach.c
+++ b/drivers/s390/s390mach.c
@@ -31,14 +31,14 @@ extern void css_reiterate_subchannels(void);
 extern struct workqueue_struct *slow_path_wq;
 extern struct work_struct slow_path_work;
 
-static void
+static NORET_TYPE void
 s390_handle_damage(char *msg)
 {
-        printk(KERN_EMERG "%s\n", msg);
 #ifdef CONFIG_SMP
         smp_send_stop();
 #endif
         disabled_wait((unsigned long) __builtin_return_address(0));
+        for(;;);
 }
 
 /*
@@ -122,40 +122,39 @@ 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);
+
 /*
- * machine check handler.
+ * Main machine check handler function. Will be called with interrupts enabled
+ * or disabled and machine checks enabled or disabled.
  */
 void
-s390_do_machine_check(void)
+s390_handle_mcck(void)
 {
-        struct mci *mci;
-
-        mci = (struct mci *) &S390_lowcore.mcck_interruption_code;
+        unsigned long flags;
+        struct mcck_struct mcck;
 
-        if (mci->sd)            /* system damage */
-                s390_handle_damage("received system damage machine check\n");
+        /*
+         * 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 (mci->pd)            /* instruction processing damage */
-                s390_handle_damage("received instruction processing "
-                                   "damage machine check\n");
-
-        if (mci->se)            /* storage error uncorrected */
-                s390_handle_damage("received storage error uncorrected "
-                                   "machine check\n");
-
-        if (mci->sc)            /* storage error corrected */
-                printk(KERN_WARNING
-                       "received storage error corrected machine check\n");
-
-        if (mci->ke)            /* storage key-error uncorrected */
-                s390_handle_damage("received storage key-error uncorrected "
-                                   "machine check\n");
-
-        if (mci->ds && mci->fa) /* storage degradation */
-                s390_handle_damage("received storage degradation machine "
-                                   "check\n");
-
-        if (mci->cp)            /* channel report word pending */
+        if (mcck.channel_report)
                 up(&m_sem);
 
 #ifdef CONFIG_MACHCHK_WARNING
@@ -168,7 +167,7 @@ s390_do_machine_check(void)
  * On VM we only get one interrupt per virtally presented machinecheck.
  * Though one suffices, we may get one interrupt per (virtual) processor.
  */
-        if (mci->w) {   /* WARNING pending ? */
+        if (mcck.warning) {     /* WARNING pending ? */
                 static int mchchk_wng_posted = 0;
                 /*
                  * Use single machine clear, as we cannot handle smp right now
@@ -178,6 +177,261 @@ s390_do_machine_check(void)
                         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));
+                        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);
+        }
 }
 
 /*
@@ -189,9 +443,8 @@ static int
 machine_check_init(void)
 {
         init_MUTEX_LOCKED(&m_sem);
-        ctl_clear_bit(14, 25);  /* disable damage MCH */
-        ctl_set_bit(14, 26);    /* enable degradation MCH */
-        ctl_set_bit(14, 27);    /* enable system recovery MCH */
+        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