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