1 files changed, 205 insertions, 56 deletions

diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 0b499f5cbe19..a668993ff577 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -71,9 +71,30 @@ struct pcpu {
 };
 
 static u8 boot_cpu_type;
-static u16 boot_cpu_address;
 static struct pcpu pcpu_devices[NR_CPUS];
 
+unsigned int smp_cpu_mt_shift;
+EXPORT_SYMBOL(smp_cpu_mt_shift);
+
+unsigned int smp_cpu_mtid;
+EXPORT_SYMBOL(smp_cpu_mtid);
+
+static unsigned int smp_max_threads __initdata = -1U;
+
+static int __init early_nosmt(char *s)
+{
+	smp_max_threads = 1;
+	return 0;
+}
+early_param("nosmt", early_nosmt);
+
+static int __init early_smt(char *s)
+{
+	get_option(&s, &smp_max_threads);
+	return 0;
+}
+early_param("smt", early_smt);
+
 /*
  * The smp_cpu_state_mutex must be held when changing the state or polarization
  * member of a pcpu data structure within the pcpu_devices arreay.
@@ -132,7 +153,7 @@ static inline int pcpu_running(struct pcpu *pcpu)
 /*
  * Find struct pcpu by cpu address.
  */
-static struct pcpu *pcpu_find_address(const struct cpumask *mask, int address)
+static struct pcpu *pcpu_find_address(const struct cpumask *mask, u16 address)
 {
 	int cpu;
 
@@ -299,6 +320,32 @@ static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
 }
 
 /*
+ * Enable additional logical cpus for multi-threading.
+ */
+static int pcpu_set_smt(unsigned int mtid)
+{
+	register unsigned long reg1 asm ("1") = (unsigned long) mtid;
+	int cc;
+
+	if (smp_cpu_mtid == mtid)
+		return 0;
+	asm volatile(
+		"	sigp	%1,0,%2	# sigp set multi-threading\n"
+		"	ipm	%0\n"
+		"	srl	%0,28\n"
+		: "=d" (cc) : "d" (reg1), "K" (SIGP_SET_MULTI_THREADING)
+		: "cc");
+	if (cc == 0) {
+		smp_cpu_mtid = mtid;
+		smp_cpu_mt_shift = 0;
+		while (smp_cpu_mtid >= (1U << smp_cpu_mt_shift))
+			smp_cpu_mt_shift++;
+		pcpu_devices[0].address = stap();
+	}
+	return cc;
+}
+
+/*
  * Call function on an online CPU.
  */
 void smp_call_online_cpu(void (*func)(void *), void *data)
@@ -512,22 +559,17 @@ EXPORT_SYMBOL(smp_ctl_clear_bit);
 
 #ifdef CONFIG_CRASH_DUMP
 
-static void __init smp_get_save_area(int cpu, u16 address)
+static inline void __smp_store_cpu_state(int cpu, u16 address, int is_boot_cpu)
 {
 	void *lc = pcpu_devices[0].lowcore;
 	struct save_area_ext *sa_ext;
 	unsigned long vx_sa;
 
-	if (is_kdump_kernel())
-		return;
-	if (!OLDMEM_BASE && (address == boot_cpu_address ||
-			     ipl_info.type != IPL_TYPE_FCP_DUMP))
-		return;
 	sa_ext = dump_save_area_create(cpu);
 	if (!sa_ext)
 		panic("could not allocate memory for save area\n");
-	if (address == boot_cpu_address) {
-		/* Copy the registers of the boot cpu. */
+	if (is_boot_cpu) {
+		/* Copy the registers of the boot CPU. */
 		copy_oldmem_page(1, (void *) &sa_ext->sa, sizeof(sa_ext->sa),
 				 SAVE_AREA_BASE - PAGE_SIZE, 0);
 		if (MACHINE_HAS_VX)
@@ -548,6 +590,64 @@ static void __init smp_get_save_area(int cpu, u16 address)
 	free_page(vx_sa);
 }
 
+/*
+ * Collect CPU state of the previous, crashed system.
+ * There are four cases:
+ * 1) standard zfcp dump
+ *    condition: OLDMEM_BASE == NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
+ *    The state for all CPUs except the boot CPU needs to be collected
+ *    with sigp stop-and-store-status. The boot CPU state is located in
+ *    the absolute lowcore of the memory stored in the HSA. The zcore code
+ *    will allocate the save area and copy the boot CPU state from the HSA.
+ * 2) stand-alone kdump for SCSI (zfcp dump with swapped memory)
+ *    condition: OLDMEM_BASE != NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
+ *    The state for all CPUs except the boot CPU needs to be collected
+ *    with sigp stop-and-store-status. The firmware or the boot-loader
+ *    stored the registers of the boot CPU in the absolute lowcore in the
+ *    memory of the old system.
+ * 3) kdump and the old kernel did not store the CPU state,
+ *    or stand-alone kdump for DASD
+ *    condition: OLDMEM_BASE != NULL && !is_kdump_kernel()
+ *    The state for all CPUs except the boot CPU needs to be collected
+ *    with sigp stop-and-store-status. The kexec code or the boot-loader
+ *    stored the registers of the boot CPU in the memory of the old system.
+ * 4) kdump and the old kernel stored the CPU state
+ *    condition: OLDMEM_BASE != NULL && is_kdump_kernel()
+ *    The state of all CPUs is stored in ELF sections in the memory of the
+ *    old system. The ELF sections are picked up by the crash_dump code
+ *    via elfcorehdr_addr.
+ */
+static void __init smp_store_cpu_states(struct sclp_cpu_info *info)
+{
+	unsigned int cpu, address, i, j;
+	int is_boot_cpu;
+
+	if (is_kdump_kernel())
+		/* Previous system stored the CPU states. Nothing to do. */
+		return;
+	if (!(OLDMEM_BASE || ipl_info.type == IPL_TYPE_FCP_DUMP))
+		/* No previous system present, normal boot. */
+		return;
+	/* Set multi-threading state to the previous system. */
+	pcpu_set_smt(sclp_get_mtid_prev());
+	/* Collect CPU states. */
+	cpu = 0;
+	for (i = 0; i < info->configured; i++) {
+		/* Skip CPUs with different CPU type. */
+		if (info->has_cpu_type && info->cpu[i].type != boot_cpu_type)
+			continue;
+		for (j = 0; j <= smp_cpu_mtid; j++, cpu++) {
+			address = (info->cpu[i].core_id << smp_cpu_mt_shift) + j;
+			is_boot_cpu = (address == pcpu_devices[0].address);
+			if (is_boot_cpu && !OLDMEM_BASE)
+				/* Skip boot CPU for standard zfcp dump. */
+				continue;
+			/* Get state for this CPu. */
+			__smp_store_cpu_state(cpu, address, is_boot_cpu);
+		}
+	}
+}
+
 int smp_store_status(int cpu)
 {
 	unsigned long vx_sa;
@@ -565,10 +665,6 @@ int smp_store_status(int cpu)
 	return 0;
 }
 
-#else /* CONFIG_CRASH_DUMP */
-
-static inline void smp_get_save_area(int cpu, u16 address) { }
-
 #endif /* CONFIG_CRASH_DUMP */
 
 void smp_cpu_set_polarization(int cpu, int val)
@@ -590,11 +686,13 @@ static struct sclp_cpu_info *smp_get_cpu_info(void)
 	info = kzalloc(sizeof(*info), GFP_KERNEL);
 	if (info && (use_sigp_detection || sclp_get_cpu_info(info))) {
 		use_sigp_detection = 1;
-		for (address = 0; address <= MAX_CPU_ADDRESS; address++) {
+		for (address = 0; address <= MAX_CPU_ADDRESS;
+		     address += (1U << smp_cpu_mt_shift)) {
 			if (__pcpu_sigp_relax(address, SIGP_SENSE, 0, NULL) ==
 			    SIGP_CC_NOT_OPERATIONAL)
 				continue;
-			info->cpu[info->configured].address = address;
+			info->cpu[info->configured].core_id =
+				address >> smp_cpu_mt_shift;
 			info->configured++;
 		}
 		info->combined = info->configured;
@@ -608,7 +706,8 @@ static int __smp_rescan_cpus(struct sclp_cpu_info *info, int sysfs_add)
 {
 	struct pcpu *pcpu;
 	cpumask_t avail;
-	int cpu, nr, i;
+	int cpu, nr, i, j;
+	u16 address;
 
 	nr = 0;
 	cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
@@ -616,51 +715,76 @@ static int __smp_rescan_cpus(struct sclp_cpu_info *info, int sysfs_add)
 	for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
 		if (info->has_cpu_type && info->cpu[i].type != boot_cpu_type)
 			continue;
-		if (pcpu_find_address(cpu_present_mask, info->cpu[i].address))
-			continue;
-		pcpu = pcpu_devices + cpu;
-		pcpu->address = info->cpu[i].address;
-		pcpu->state = (i >= info->configured) ?
-			CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
-		smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
-		set_cpu_present(cpu, true);
-		if (sysfs_add && smp_add_present_cpu(cpu) != 0)
-			set_cpu_present(cpu, false);
-		else
-			nr++;
-		cpu = cpumask_next(cpu, &avail);
+		address = info->cpu[i].core_id << smp_cpu_mt_shift;
+		for (j = 0; j <= smp_cpu_mtid; j++) {
+			if (pcpu_find_address(cpu_present_mask, address + j))
+				continue;
+			pcpu = pcpu_devices + cpu;
+			pcpu->address = address + j;
+			pcpu->state =
+				(cpu >= info->configured*(smp_cpu_mtid + 1)) ?
+				CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
+			smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
+			set_cpu_present(cpu, true);
+			if (sysfs_add && smp_add_present_cpu(cpu) != 0)
+				set_cpu_present(cpu, false);
+			else
+				nr++;
+			cpu = cpumask_next(cpu, &avail);
+			if (cpu >= nr_cpu_ids)
+				break;
+		}
 	}
 	return nr;
 }
 
 static void __init smp_detect_cpus(void)
 {
-	unsigned int cpu, c_cpus, s_cpus;
+	unsigned int cpu, mtid, c_cpus, s_cpus;
 	struct sclp_cpu_info *info;
+	u16 address;
 
+	/* Get CPU information */
 	info = smp_get_cpu_info();
 	if (!info)
 		panic("smp_detect_cpus failed to allocate memory\n");
+
+	/* Find boot CPU type */
 	if (info->has_cpu_type) {
-		for (cpu = 0; cpu < info->combined; cpu++) {
-			if (info->cpu[cpu].address != boot_cpu_address)
-				continue;
-			/* The boot cpu dictates the cpu type. */
-			boot_cpu_type = info->cpu[cpu].type;
-			break;
-		}
+		address = stap();
+		for (cpu = 0; cpu < info->combined; cpu++)
+			if (info->cpu[cpu].core_id == address) {
+				/* The boot cpu dictates the cpu type. */
+				boot_cpu_type = info->cpu[cpu].type;
+				break;
+			}
+		if (cpu >= info->combined)
+			panic("Could not find boot CPU type");
 	}
+
+#ifdef CONFIG_CRASH_DUMP
+	/* Collect CPU state of previous system */
+	smp_store_cpu_states(info);
+#endif
+
+	/* Set multi-threading state for the current system */
+	mtid = sclp_get_mtid(boot_cpu_type);
+	mtid = (mtid < smp_max_threads) ? mtid : smp_max_threads - 1;
+	pcpu_set_smt(mtid);
+
+	/* Print number of CPUs */
 	c_cpus = s_cpus = 0;
 	for (cpu = 0; cpu < info->combined; cpu++) {
 		if (info->has_cpu_type && info->cpu[cpu].type != boot_cpu_type)
 			continue;
-		if (cpu < info->configured) {
-			smp_get_save_area(c_cpus, info->cpu[cpu].address);
-			c_cpus++;
-		} else
-			s_cpus++;
+		if (cpu < info->configured)
+			c_cpus += smp_cpu_mtid + 1;
+		else
+			s_cpus += smp_cpu_mtid + 1;
 	}
 	pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
+
+	/* Add CPUs present at boot */
 	get_online_cpus();
 	__smp_rescan_cpus(info, 0);
 	put_online_cpus();
@@ -696,12 +820,23 @@ static void smp_start_secondary(void *cpuvoid)
 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
 	struct pcpu *pcpu;
-	int rc;
+	int base, i, rc;
 
 	pcpu = pcpu_devices + cpu;
 	if (pcpu->state != CPU_STATE_CONFIGURED)
 		return -EIO;
-	if (pcpu_sigp_retry(pcpu, SIGP_INITIAL_CPU_RESET, 0) !=
+	base = cpu - (cpu % (smp_cpu_mtid + 1));
+	for (i = 0; i <= smp_cpu_mtid; i++) {
+		if (base + i < nr_cpu_ids)
+			if (cpu_online(base + i))
+				break;
+	}
+	/*
+	 * If this is the first CPU of the core to get online
+	 * do an initial CPU reset.
+	 */
+	if (i > smp_cpu_mtid &&
+	    pcpu_sigp_retry(pcpu_devices + base, SIGP_INITIAL_CPU_RESET, 0) !=
 	    SIGP_CC_ORDER_CODE_ACCEPTED)
 		return -EIO;
 
@@ -774,7 +909,8 @@ void __init smp_fill_possible_mask(void)
 {
 	unsigned int possible, sclp, cpu;
 
-	sclp = sclp_get_max_cpu() ?: nr_cpu_ids;
+	sclp = min(smp_max_threads, sclp_get_mtid_max() + 1);
+	sclp = sclp_get_max_cpu()*sclp ?: nr_cpu_ids;
 	possible = setup_possible_cpus ?: nr_cpu_ids;
 	possible = min(possible, sclp);
 	for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
@@ -796,9 +932,8 @@ void __init smp_prepare_boot_cpu(void)
 {
 	struct pcpu *pcpu = pcpu_devices;
 
-	boot_cpu_address = stap();
 	pcpu->state = CPU_STATE_CONFIGURED;
-	pcpu->address = boot_cpu_address;
+	pcpu->address = stap();
 	pcpu->lowcore = (struct _lowcore *)(unsigned long) store_prefix();
 	pcpu->async_stack = S390_lowcore.async_stack - ASYNC_SIZE
 		+ STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
@@ -848,7 +983,7 @@ static ssize_t cpu_configure_store(struct device *dev,
 				   const char *buf, size_t count)
 {
 	struct pcpu *pcpu;
-	int cpu, val, rc;
+	int cpu, val, rc, i;
 	char delim;
 
 	if (sscanf(buf, "%d %c", &val, &delim) != 1)
@@ -860,29 +995,43 @@ static ssize_t cpu_configure_store(struct device *dev,
 	rc = -EBUSY;
 	/* disallow configuration changes of online cpus and cpu 0 */
 	cpu = dev->id;
-	if (cpu_online(cpu) || cpu == 0)
+	cpu -= cpu % (smp_cpu_mtid + 1);
+	if (cpu == 0)
 		goto out;
+	for (i = 0; i <= smp_cpu_mtid; i++)
+		if (cpu_online(cpu + i))
+			goto out;
 	pcpu = pcpu_devices + cpu;
 	rc = 0;
 	switch (val) {
 	case 0:
 		if (pcpu->state != CPU_STATE_CONFIGURED)
 			break;
-		rc = sclp_cpu_deconfigure(pcpu->address);
+		rc = sclp_cpu_deconfigure(pcpu->address >> smp_cpu_mt_shift);
 		if (rc)
 			break;
-		pcpu->state = CPU_STATE_STANDBY;
-		smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
+		for (i = 0; i <= smp_cpu_mtid; i++) {
+			if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
+				continue;
+			pcpu[i].state = CPU_STATE_STANDBY;
+			smp_cpu_set_polarization(cpu + i,
+						 POLARIZATION_UNKNOWN);
+		}
 		topology_expect_change();
 		break;
 	case 1:
 		if (pcpu->state != CPU_STATE_STANDBY)
 			break;
-		rc = sclp_cpu_configure(pcpu->address);
+		rc = sclp_cpu_configure(pcpu->address >> smp_cpu_mt_shift);
 		if (rc)
 			break;
-		pcpu->state = CPU_STATE_CONFIGURED;
-		smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
+		for (i = 0; i <= smp_cpu_mtid; i++) {
+			if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
+				continue;
+			pcpu[i].state = CPU_STATE_CONFIGURED;
+			smp_cpu_set_polarization(cpu + i,
+						 POLARIZATION_UNKNOWN);
+		}
 		topology_expect_change();
 		break;
 	default: