Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1305 insertions, 0 deletions

diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
new file mode 100644
index 000000000..0031325ce
--- /dev/null
+++ b/arch/s390/kernel/smp.c
@@ -0,0 +1,1305 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  SMP related functions
+ *
+ *    Copyright IBM Corp. 1999, 2012
+ *    Author(s): Denis Joseph Barrow,
+ *		 Martin Schwidefsky <schwidefsky@de.ibm.com>,
+ *
+ *  based on other smp stuff by
+ *    (c) 1995 Alan Cox, CymruNET Ltd  <alan@cymru.net>
+ *    (c) 1998 Ingo Molnar
+ *
+ * The code outside of smp.c uses logical cpu numbers, only smp.c does
+ * the translation of logical to physical cpu ids. All new code that
+ * operates on physical cpu numbers needs to go into smp.c.
+ */
+
+#define KMSG_COMPONENT "cpu"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/workqueue.h>
+#include <linux/memblock.h>
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/err.h>
+#include <linux/spinlock.h>
+#include <linux/kernel_stat.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/irqflags.h>
+#include <linux/irq_work.h>
+#include <linux/cpu.h>
+#include <linux/slab.h>
+#include <linux/sched/hotplug.h>
+#include <linux/sched/task_stack.h>
+#include <linux/crash_dump.h>
+#include <linux/kprobes.h>
+#include <asm/asm-offsets.h>
+#include <asm/diag.h>
+#include <asm/switch_to.h>
+#include <asm/facility.h>
+#include <asm/ipl.h>
+#include <asm/setup.h>
+#include <asm/irq.h>
+#include <asm/tlbflush.h>
+#include <asm/vtimer.h>
+#include <asm/abs_lowcore.h>
+#include <asm/sclp.h>
+#include <asm/debug.h>
+#include <asm/os_info.h>
+#include <asm/sigp.h>
+#include <asm/idle.h>
+#include <asm/nmi.h>
+#include <asm/stacktrace.h>
+#include <asm/topology.h>
+#include <asm/vdso.h>
+#include <asm/maccess.h>
+#include "entry.h"
+
+enum {
+	ec_schedule = 0,
+	ec_call_function_single,
+	ec_stop_cpu,
+	ec_mcck_pending,
+	ec_irq_work,
+};
+
+enum {
+	CPU_STATE_STANDBY,
+	CPU_STATE_CONFIGURED,
+};
+
+static DEFINE_PER_CPU(struct cpu *, cpu_device);
+
+struct pcpu {
+	unsigned long ec_mask;		/* bit mask for ec_xxx functions */
+	unsigned long ec_clk;		/* sigp timestamp for ec_xxx */
+	signed char state;		/* physical cpu state */
+	signed char polarization;	/* physical polarization */
+	u16 address;			/* physical cpu address */
+};
+
+static u8 boot_core_type;
+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);
+
+#ifdef CONFIG_CRASH_DUMP
+__vector128 __initdata boot_cpu_vector_save_area[__NUM_VXRS];
+#endif
+
+static unsigned int smp_max_threads __initdata = -1U;
+cpumask_t cpu_setup_mask;
+
+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.
+ */
+DEFINE_MUTEX(smp_cpu_state_mutex);
+
+/*
+ * Signal processor helper functions.
+ */
+static inline int __pcpu_sigp_relax(u16 addr, u8 order, unsigned long parm)
+{
+	int cc;
+
+	while (1) {
+		cc = __pcpu_sigp(addr, order, parm, NULL);
+		if (cc != SIGP_CC_BUSY)
+			return cc;
+		cpu_relax();
+	}
+}
+
+static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
+{
+	int cc, retry;
+
+	for (retry = 0; ; retry++) {
+		cc = __pcpu_sigp(pcpu->address, order, parm, NULL);
+		if (cc != SIGP_CC_BUSY)
+			break;
+		if (retry >= 3)
+			udelay(10);
+	}
+	return cc;
+}
+
+static inline int pcpu_stopped(struct pcpu *pcpu)
+{
+	u32 status;
+
+	if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
+			0, &status) != SIGP_CC_STATUS_STORED)
+		return 0;
+	return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
+}
+
+static inline int pcpu_running(struct pcpu *pcpu)
+{
+	if (__pcpu_sigp(pcpu->address, SIGP_SENSE_RUNNING,
+			0, NULL) != SIGP_CC_STATUS_STORED)
+		return 1;
+	/* Status stored condition code is equivalent to cpu not running. */
+	return 0;
+}
+
+/*
+ * Find struct pcpu by cpu address.
+ */
+static struct pcpu *pcpu_find_address(const struct cpumask *mask, u16 address)
+{
+	int cpu;
+
+	for_each_cpu(cpu, mask)
+		if (pcpu_devices[cpu].address == address)
+			return pcpu_devices + cpu;
+	return NULL;
+}
+
+static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
+{
+	int order;
+
+	if (test_and_set_bit(ec_bit, &pcpu->ec_mask))
+		return;
+	order = pcpu_running(pcpu) ? SIGP_EXTERNAL_CALL : SIGP_EMERGENCY_SIGNAL;
+	pcpu->ec_clk = get_tod_clock_fast();
+	pcpu_sigp_retry(pcpu, order, 0);
+}
+
+static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
+{
+	unsigned long async_stack, nodat_stack, mcck_stack;
+	struct lowcore *lc;
+
+	lc = (struct lowcore *) __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
+	nodat_stack = __get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER);
+	async_stack = stack_alloc();
+	mcck_stack = stack_alloc();
+	if (!lc || !nodat_stack || !async_stack || !mcck_stack)
+		goto out;
+	memcpy(lc, &S390_lowcore, 512);
+	memset((char *) lc + 512, 0, sizeof(*lc) - 512);
+	lc->async_stack = async_stack + STACK_INIT_OFFSET;
+	lc->nodat_stack = nodat_stack + STACK_INIT_OFFSET;
+	lc->mcck_stack = mcck_stack + STACK_INIT_OFFSET;
+	lc->cpu_nr = cpu;
+	lc->spinlock_lockval = arch_spin_lockval(cpu);
+	lc->spinlock_index = 0;
+	lc->return_lpswe = gen_lpswe(__LC_RETURN_PSW);
+	lc->return_mcck_lpswe = gen_lpswe(__LC_RETURN_MCCK_PSW);
+	lc->preempt_count = PREEMPT_DISABLED;
+	if (nmi_alloc_mcesa(&lc->mcesad))
+		goto out;
+	if (abs_lowcore_map(cpu, lc, true))
+		goto out_mcesa;
+	lowcore_ptr[cpu] = lc;
+	pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, __pa(lc));
+	return 0;
+
+out_mcesa:
+	nmi_free_mcesa(&lc->mcesad);
+out:
+	stack_free(mcck_stack);
+	stack_free(async_stack);
+	free_pages(nodat_stack, THREAD_SIZE_ORDER);
+	free_pages((unsigned long) lc, LC_ORDER);
+	return -ENOMEM;
+}
+
+static void pcpu_free_lowcore(struct pcpu *pcpu)
+{
+	unsigned long async_stack, nodat_stack, mcck_stack;
+	struct lowcore *lc;
+	int cpu;
+
+	cpu = pcpu - pcpu_devices;
+	lc = lowcore_ptr[cpu];
+	nodat_stack = lc->nodat_stack - STACK_INIT_OFFSET;
+	async_stack = lc->async_stack - STACK_INIT_OFFSET;
+	mcck_stack = lc->mcck_stack - STACK_INIT_OFFSET;
+	pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, 0);
+	lowcore_ptr[cpu] = NULL;
+	abs_lowcore_unmap(cpu);
+	nmi_free_mcesa(&lc->mcesad);
+	stack_free(async_stack);
+	stack_free(mcck_stack);
+	free_pages(nodat_stack, THREAD_SIZE_ORDER);
+	free_pages((unsigned long) lc, LC_ORDER);
+}
+
+static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
+{
+	struct lowcore *lc = lowcore_ptr[cpu];
+
+	cpumask_set_cpu(cpu, &init_mm.context.cpu_attach_mask);
+	cpumask_set_cpu(cpu, mm_cpumask(&init_mm));
+	lc->cpu_nr = cpu;
+	lc->restart_flags = RESTART_FLAG_CTLREGS;
+	lc->spinlock_lockval = arch_spin_lockval(cpu);
+	lc->spinlock_index = 0;
+	lc->percpu_offset = __per_cpu_offset[cpu];
+	lc->kernel_asce = S390_lowcore.kernel_asce;
+	lc->user_asce = s390_invalid_asce;
+	lc->machine_flags = S390_lowcore.machine_flags;
+	lc->user_timer = lc->system_timer =
+		lc->steal_timer = lc->avg_steal_timer = 0;
+	__ctl_store(lc->cregs_save_area, 0, 15);
+	lc->cregs_save_area[1] = lc->kernel_asce;
+	lc->cregs_save_area[7] = lc->user_asce;
+	save_access_regs((unsigned int *) lc->access_regs_save_area);
+	arch_spin_lock_setup(cpu);
+}
+
+static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
+{
+	struct lowcore *lc;
+	int cpu;
+
+	cpu = pcpu - pcpu_devices;
+	lc = lowcore_ptr[cpu];
+	lc->kernel_stack = (unsigned long) task_stack_page(tsk)
+		+ THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
+	lc->current_task = (unsigned long) tsk;
+	lc->lpp = LPP_MAGIC;
+	lc->current_pid = tsk->pid;
+	lc->user_timer = tsk->thread.user_timer;
+	lc->guest_timer = tsk->thread.guest_timer;
+	lc->system_timer = tsk->thread.system_timer;
+	lc->hardirq_timer = tsk->thread.hardirq_timer;
+	lc->softirq_timer = tsk->thread.softirq_timer;
+	lc->steal_timer = 0;
+}
+
+static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
+{
+	struct lowcore *lc;
+	int cpu;
+
+	cpu = pcpu - pcpu_devices;
+	lc = lowcore_ptr[cpu];
+	lc->restart_stack = lc->kernel_stack;
+	lc->restart_fn = (unsigned long) func;
+	lc->restart_data = (unsigned long) data;
+	lc->restart_source = -1U;
+	pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
+}
+
+typedef void (pcpu_delegate_fn)(void *);
+
+/*
+ * Call function via PSW restart on pcpu and stop the current cpu.
+ */
+static void __pcpu_delegate(pcpu_delegate_fn *func, void *data)
+{
+	func(data);	/* should not return */
+}
+
+static void pcpu_delegate(struct pcpu *pcpu,
+			  pcpu_delegate_fn *func,
+			  void *data, unsigned long stack)
+{
+	struct lowcore *lc, *abs_lc;
+	unsigned int source_cpu;
+	unsigned long flags;
+
+	lc = lowcore_ptr[pcpu - pcpu_devices];
+	source_cpu = stap();
+	__load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
+	if (pcpu->address == source_cpu) {
+		call_on_stack(2, stack, void, __pcpu_delegate,
+			      pcpu_delegate_fn *, func, void *, data);
+	}
+	/* Stop target cpu (if func returns this stops the current cpu). */
+	pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
+	/* Restart func on the target cpu and stop the current cpu. */
+	if (lc) {
+		lc->restart_stack = stack;
+		lc->restart_fn = (unsigned long)func;
+		lc->restart_data = (unsigned long)data;
+		lc->restart_source = source_cpu;
+	} else {
+		abs_lc = get_abs_lowcore(&flags);
+		abs_lc->restart_stack = stack;
+		abs_lc->restart_fn = (unsigned long)func;
+		abs_lc->restart_data = (unsigned long)data;
+		abs_lc->restart_source = source_cpu;
+		put_abs_lowcore(abs_lc, flags);
+	}
+	__bpon();
+	asm volatile(
+		"0:	sigp	0,%0,%2	# sigp restart to target cpu\n"
+		"	brc	2,0b	# busy, try again\n"
+		"1:	sigp	0,%1,%3	# sigp stop to current cpu\n"
+		"	brc	2,1b	# busy, try again\n"
+		: : "d" (pcpu->address), "d" (source_cpu),
+		    "K" (SIGP_RESTART), "K" (SIGP_STOP)
+		: "0", "1", "cc");
+	for (;;) ;
+}
+
+/*
+ * Enable additional logical cpus for multi-threading.
+ */
+static int pcpu_set_smt(unsigned int mtid)
+{
+	int cc;
+
+	if (smp_cpu_mtid == mtid)
+		return 0;
+	cc = __pcpu_sigp(0, SIGP_SET_MULTI_THREADING, mtid, NULL);
+	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)
+{
+	struct pcpu *pcpu;
+
+	/* Use the current cpu if it is online. */
+	pcpu = pcpu_find_address(cpu_online_mask, stap());
+	if (!pcpu)
+		/* Use the first online cpu. */
+		pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
+	pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
+}
+
+/*
+ * Call function on the ipl CPU.
+ */
+void smp_call_ipl_cpu(void (*func)(void *), void *data)
+{
+	struct lowcore *lc = lowcore_ptr[0];
+
+	if (pcpu_devices[0].address == stap())
+		lc = &S390_lowcore;
+
+	pcpu_delegate(&pcpu_devices[0], func, data,
+		      lc->nodat_stack);
+}
+
+int smp_find_processor_id(u16 address)
+{
+	int cpu;
+
+	for_each_present_cpu(cpu)
+		if (pcpu_devices[cpu].address == address)
+			return cpu;
+	return -1;
+}
+
+void schedule_mcck_handler(void)
+{
+	pcpu_ec_call(pcpu_devices + smp_processor_id(), ec_mcck_pending);
+}
+
+bool notrace arch_vcpu_is_preempted(int cpu)
+{
+	if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu))
+		return false;
+	if (pcpu_running(pcpu_devices + cpu))
+		return false;
+	return true;
+}
+EXPORT_SYMBOL(arch_vcpu_is_preempted);
+
+void notrace smp_yield_cpu(int cpu)
+{
+	if (!MACHINE_HAS_DIAG9C)
+		return;
+	diag_stat_inc_norecursion(DIAG_STAT_X09C);
+	asm volatile("diag %0,0,0x9c"
+		     : : "d" (pcpu_devices[cpu].address));
+}
+EXPORT_SYMBOL_GPL(smp_yield_cpu);
+
+/*
+ * Send cpus emergency shutdown signal. This gives the cpus the
+ * opportunity to complete outstanding interrupts.
+ */
+void notrace smp_emergency_stop(void)
+{
+	static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
+	static cpumask_t cpumask;
+	u64 end;
+	int cpu;
+
+	arch_spin_lock(&lock);
+	cpumask_copy(&cpumask, cpu_online_mask);
+	cpumask_clear_cpu(smp_processor_id(), &cpumask);
+
+	end = get_tod_clock() + (1000000UL << 12);
+	for_each_cpu(cpu, &cpumask) {
+		struct pcpu *pcpu = pcpu_devices + cpu;
+		set_bit(ec_stop_cpu, &pcpu->ec_mask);
+		while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
+				   0, NULL) == SIGP_CC_BUSY &&
+		       get_tod_clock() < end)
+			cpu_relax();
+	}
+	while (get_tod_clock() < end) {
+		for_each_cpu(cpu, &cpumask)
+			if (pcpu_stopped(pcpu_devices + cpu))
+				cpumask_clear_cpu(cpu, &cpumask);
+		if (cpumask_empty(&cpumask))
+			break;
+		cpu_relax();
+	}
+	arch_spin_unlock(&lock);
+}
+NOKPROBE_SYMBOL(smp_emergency_stop);
+
+/*
+ * Stop all cpus but the current one.
+ */
+void smp_send_stop(void)
+{
+	int cpu;
+
+	/* Disable all interrupts/machine checks */
+	__load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
+	trace_hardirqs_off();
+
+	debug_set_critical();
+
+	if (oops_in_progress)
+		smp_emergency_stop();
+
+	/* stop all processors */
+	for_each_online_cpu(cpu) {
+		if (cpu == smp_processor_id())
+			continue;
+		pcpu_sigp_retry(pcpu_devices + cpu, SIGP_STOP, 0);
+		while (!pcpu_stopped(pcpu_devices + cpu))
+			cpu_relax();
+	}
+}
+
+/*
+ * This is the main routine where commands issued by other
+ * cpus are handled.
+ */
+static void smp_handle_ext_call(void)
+{
+	unsigned long bits;
+
+	/* handle bit signal external calls */
+	bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
+	if (test_bit(ec_stop_cpu, &bits))
+		smp_stop_cpu();
+	if (test_bit(ec_schedule, &bits))
+		scheduler_ipi();
+	if (test_bit(ec_call_function_single, &bits))
+		generic_smp_call_function_single_interrupt();
+	if (test_bit(ec_mcck_pending, &bits))
+		__s390_handle_mcck();
+	if (test_bit(ec_irq_work, &bits))
+		irq_work_run();
+}
+
+static void do_ext_call_interrupt(struct ext_code ext_code,
+				  unsigned int param32, unsigned long param64)
+{
+	inc_irq_stat(ext_code.code == 0x1202 ? IRQEXT_EXC : IRQEXT_EMS);
+	smp_handle_ext_call();
+}
+
+void arch_send_call_function_ipi_mask(const struct cpumask *mask)
+{
+	int cpu;
+
+	for_each_cpu(cpu, mask)
+		pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
+}
+
+void arch_send_call_function_single_ipi(int cpu)
+{
+	pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
+}
+
+/*
+ * this function sends a 'reschedule' IPI to another CPU.
+ * it goes straight through and wastes no time serializing
+ * anything. Worst case is that we lose a reschedule ...
+ */
+void smp_send_reschedule(int cpu)
+{
+	pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
+}
+
+#ifdef CONFIG_IRQ_WORK
+void arch_irq_work_raise(void)
+{
+	pcpu_ec_call(pcpu_devices + smp_processor_id(), ec_irq_work);
+}
+#endif
+
+/*
+ * parameter area for the set/clear control bit callbacks
+ */
+struct ec_creg_mask_parms {
+	unsigned long orval;
+	unsigned long andval;
+	int cr;
+};
+
+/*
+ * callback for setting/clearing control bits
+ */
+static void smp_ctl_bit_callback(void *info)
+{
+	struct ec_creg_mask_parms *pp = info;
+	unsigned long cregs[16];
+
+	__ctl_store(cregs, 0, 15);
+	cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
+	__ctl_load(cregs, 0, 15);
+}
+
+static DEFINE_SPINLOCK(ctl_lock);
+
+void smp_ctl_set_clear_bit(int cr, int bit, bool set)
+{
+	struct ec_creg_mask_parms parms = { .cr = cr, };
+	struct lowcore *abs_lc;
+	unsigned long flags;
+	u64 ctlreg;
+
+	if (set) {
+		parms.orval = 1UL << bit;
+		parms.andval = -1UL;
+	} else {
+		parms.orval = 0;
+		parms.andval = ~(1UL << bit);
+	}
+	spin_lock(&ctl_lock);
+	abs_lc = get_abs_lowcore(&flags);
+	ctlreg = abs_lc->cregs_save_area[cr];
+	ctlreg = (ctlreg & parms.andval) | parms.orval;
+	abs_lc->cregs_save_area[cr] = ctlreg;
+	put_abs_lowcore(abs_lc, flags);
+	spin_unlock(&ctl_lock);
+	on_each_cpu(smp_ctl_bit_callback, &parms, 1);
+}
+EXPORT_SYMBOL(smp_ctl_set_clear_bit);
+
+#ifdef CONFIG_CRASH_DUMP
+
+int smp_store_status(int cpu)
+{
+	struct lowcore *lc;
+	struct pcpu *pcpu;
+	unsigned long pa;
+
+	pcpu = pcpu_devices + cpu;
+	lc = lowcore_ptr[cpu];
+	pa = __pa(&lc->floating_pt_save_area);
+	if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_STATUS_AT_ADDRESS,
+			      pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
+		return -EIO;
+	if (!MACHINE_HAS_VX && !MACHINE_HAS_GS)
+		return 0;
+	pa = lc->mcesad & MCESA_ORIGIN_MASK;
+	if (MACHINE_HAS_GS)
+		pa |= lc->mcesad & MCESA_LC_MASK;
+	if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
+			      pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
+		return -EIO;
+	return 0;
+}
+
+/*
+ * Collect CPU state of the previous, crashed system.
+ * There are four cases:
+ * 1) standard zfcp/nvme dump
+ *    condition: OLDMEM_BASE == NULL && is_ipl_type_dump() == true
+ *    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 copy the boot CPU state from the HSA.
+ * 2) stand-alone kdump for SCSI/NVMe (zfcp/nvme dump with swapped memory)
+ *    condition: OLDMEM_BASE != NULL && is_ipl_type_dump() == true
+ *    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()
+ *    This case does not exist for s390 anymore, setup_arch explicitly
+ *    deactivates the elfcorehdr= kernel parameter
+ */
+static bool dump_available(void)
+{
+	return oldmem_data.start || is_ipl_type_dump();
+}
+
+void __init smp_save_dump_ipl_cpu(void)
+{
+	struct save_area *sa;
+	void *regs;
+
+	if (!dump_available())
+		return;
+	sa = save_area_alloc(true);
+	regs = memblock_alloc(512, 8);
+	if (!sa || !regs)
+		panic("could not allocate memory for boot CPU save area\n");
+	copy_oldmem_kernel(regs, __LC_FPREGS_SAVE_AREA, 512);
+	save_area_add_regs(sa, regs);
+	memblock_free(regs, 512);
+	if (MACHINE_HAS_VX)
+		save_area_add_vxrs(sa, boot_cpu_vector_save_area);
+}
+
+void __init smp_save_dump_secondary_cpus(void)
+{
+	int addr, boot_cpu_addr, max_cpu_addr;
+	struct save_area *sa;
+	void *page;
+
+	if (!dump_available())
+		return;
+	/* Allocate a page as dumping area for the store status sigps */
+	page = memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
+	if (!page)
+		panic("ERROR: Failed to allocate %lx bytes below %lx\n",
+		      PAGE_SIZE, 1UL << 31);
+
+	/* Set multi-threading state to the previous system. */
+	pcpu_set_smt(sclp.mtid_prev);
+	boot_cpu_addr = stap();
+	max_cpu_addr = SCLP_MAX_CORES << sclp.mtid_prev;
+	for (addr = 0; addr <= max_cpu_addr; addr++) {
+		if (addr == boot_cpu_addr)
+			continue;
+		if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0) ==
+		    SIGP_CC_NOT_OPERATIONAL)
+			continue;
+		sa = save_area_alloc(false);
+		if (!sa)
+			panic("could not allocate memory for save area\n");
+		__pcpu_sigp_relax(addr, SIGP_STORE_STATUS_AT_ADDRESS, __pa(page));
+		save_area_add_regs(sa, page);
+		if (MACHINE_HAS_VX) {
+			__pcpu_sigp_relax(addr, SIGP_STORE_ADDITIONAL_STATUS, __pa(page));
+			save_area_add_vxrs(sa, page);
+		}
+	}
+	memblock_free(page, PAGE_SIZE);
+	diag_amode31_ops.diag308_reset();
+	pcpu_set_smt(0);
+}
+#endif /* CONFIG_CRASH_DUMP */
+
+void smp_cpu_set_polarization(int cpu, int val)
+{
+	pcpu_devices[cpu].polarization = val;
+}
+
+int smp_cpu_get_polarization(int cpu)
+{
+	return pcpu_devices[cpu].polarization;
+}
+
+int smp_cpu_get_cpu_address(int cpu)
+{
+	return pcpu_devices[cpu].address;
+}
+
+static void __ref smp_get_core_info(struct sclp_core_info *info, int early)
+{
+	static int use_sigp_detection;
+	int address;
+
+	if (use_sigp_detection || sclp_get_core_info(info, early)) {
+		use_sigp_detection = 1;
+		for (address = 0;
+		     address < (SCLP_MAX_CORES << smp_cpu_mt_shift);
+		     address += (1U << smp_cpu_mt_shift)) {
+			if (__pcpu_sigp_relax(address, SIGP_SENSE, 0) ==
+			    SIGP_CC_NOT_OPERATIONAL)
+				continue;
+			info->core[info->configured].core_id =
+				address >> smp_cpu_mt_shift;
+			info->configured++;
+		}
+		info->combined = info->configured;
+	}
+}
+
+static int smp_add_present_cpu(int cpu);
+
+static int smp_add_core(struct sclp_core_entry *core, cpumask_t *avail,
+			bool configured, bool early)
+{
+	struct pcpu *pcpu;
+	int cpu, nr, i;
+	u16 address;
+
+	nr = 0;
+	if (sclp.has_core_type && core->type != boot_core_type)
+		return nr;
+	cpu = cpumask_first(avail);
+	address = core->core_id << smp_cpu_mt_shift;
+	for (i = 0; (i <= smp_cpu_mtid) && (cpu < nr_cpu_ids); i++) {
+		if (pcpu_find_address(cpu_present_mask, address + i))
+			continue;
+		pcpu = pcpu_devices + cpu;
+		pcpu->address = address + i;
+		if (configured)
+			pcpu->state = CPU_STATE_CONFIGURED;
+		else
+			pcpu->state = CPU_STATE_STANDBY;
+		smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
+		set_cpu_present(cpu, true);
+		if (!early && smp_add_present_cpu(cpu) != 0)
+			set_cpu_present(cpu, false);
+		else
+			nr++;
+		cpumask_clear_cpu(cpu, avail);
+		cpu = cpumask_next(cpu, avail);
+	}
+	return nr;
+}
+
+static int __smp_rescan_cpus(struct sclp_core_info *info, bool early)
+{
+	struct sclp_core_entry *core;
+	static cpumask_t avail;
+	bool configured;
+	u16 core_id;
+	int nr, i;
+
+	cpus_read_lock();
+	mutex_lock(&smp_cpu_state_mutex);
+	nr = 0;
+	cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
+	/*
+	 * Add IPL core first (which got logical CPU number 0) to make sure
+	 * that all SMT threads get subsequent logical CPU numbers.
+	 */
+	if (early) {
+		core_id = pcpu_devices[0].address >> smp_cpu_mt_shift;
+		for (i = 0; i < info->configured; i++) {
+			core = &info->core[i];
+			if (core->core_id == core_id) {
+				nr += smp_add_core(core, &avail, true, early);
+				break;
+			}
+		}
+	}
+	for (i = 0; i < info->combined; i++) {
+		configured = i < info->configured;
+		nr += smp_add_core(&info->core[i], &avail, configured, early);
+	}
+	mutex_unlock(&smp_cpu_state_mutex);
+	cpus_read_unlock();
+	return nr;
+}
+
+void __init smp_detect_cpus(void)
+{
+	unsigned int cpu, mtid, c_cpus, s_cpus;
+	struct sclp_core_info *info;
+	u16 address;
+
+	/* Get CPU information */
+	info = memblock_alloc(sizeof(*info), 8);
+	if (!info)
+		panic("%s: Failed to allocate %zu bytes align=0x%x\n",
+		      __func__, sizeof(*info), 8);
+	smp_get_core_info(info, 1);
+	/* Find boot CPU type */
+	if (sclp.has_core_type) {
+		address = stap();
+		for (cpu = 0; cpu < info->combined; cpu++)
+			if (info->core[cpu].core_id == address) {
+				/* The boot cpu dictates the cpu type. */
+				boot_core_type = info->core[cpu].type;
+				break;
+			}
+		if (cpu >= info->combined)
+			panic("Could not find boot CPU type");
+	}
+
+	/* Set multi-threading state for the current system */
+	mtid = boot_core_type ? sclp.mtid : sclp.mtid_cp;
+	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 (sclp.has_core_type &&
+		    info->core[cpu].type != boot_core_type)
+			continue;
+		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 */
+	__smp_rescan_cpus(info, true);
+	memblock_free(info, sizeof(*info));
+}
+
+/*
+ *	Activate a secondary processor.
+ */
+static void smp_start_secondary(void *cpuvoid)
+{
+	int cpu = raw_smp_processor_id();
+
+	S390_lowcore.last_update_clock = get_tod_clock();
+	S390_lowcore.restart_stack = (unsigned long)restart_stack;
+	S390_lowcore.restart_fn = (unsigned long)do_restart;
+	S390_lowcore.restart_data = 0;
+	S390_lowcore.restart_source = -1U;
+	S390_lowcore.restart_flags = 0;
+	restore_access_regs(S390_lowcore.access_regs_save_area);
+	cpu_init();
+	rcu_cpu_starting(cpu);
+	init_cpu_timer();
+	vtime_init();
+	vdso_getcpu_init();
+	pfault_init();
+	cpumask_set_cpu(cpu, &cpu_setup_mask);
+	update_cpu_masks();
+	notify_cpu_starting(cpu);
+	if (topology_cpu_dedicated(cpu))
+		set_cpu_flag(CIF_DEDICATED_CPU);
+	else
+		clear_cpu_flag(CIF_DEDICATED_CPU);
+	set_cpu_online(cpu, true);
+	inc_irq_stat(CPU_RST);
+	local_irq_enable();
+	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
+}
+
+/* Upping and downing of CPUs */
+int __cpu_up(unsigned int cpu, struct task_struct *tidle)
+{
+	struct pcpu *pcpu = pcpu_devices + cpu;
+	int rc;
+
+	if (pcpu->state != CPU_STATE_CONFIGURED)
+		return -EIO;
+	if (pcpu_sigp_retry(pcpu, SIGP_INITIAL_CPU_RESET, 0) !=
+	    SIGP_CC_ORDER_CODE_ACCEPTED)
+		return -EIO;
+
+	rc = pcpu_alloc_lowcore(pcpu, cpu);
+	if (rc)
+		return rc;
+	pcpu_prepare_secondary(pcpu, cpu);
+	pcpu_attach_task(pcpu, tidle);
+	pcpu_start_fn(pcpu, smp_start_secondary, NULL);
+	/* Wait until cpu puts itself in the online & active maps */
+	while (!cpu_online(cpu))
+		cpu_relax();
+	return 0;
+}
+
+static unsigned int setup_possible_cpus __initdata;
+
+static int __init _setup_possible_cpus(char *s)
+{
+	get_option(&s, &setup_possible_cpus);
+	return 0;
+}
+early_param("possible_cpus", _setup_possible_cpus);
+
+int __cpu_disable(void)
+{
+	unsigned long cregs[16];
+	int cpu;
+
+	/* Handle possible pending IPIs */
+	smp_handle_ext_call();
+	cpu = smp_processor_id();
+	set_cpu_online(cpu, false);
+	cpumask_clear_cpu(cpu, &cpu_setup_mask);
+	update_cpu_masks();
+	/* Disable pseudo page faults on this cpu. */
+	pfault_fini();
+	/* Disable interrupt sources via control register. */
+	__ctl_store(cregs, 0, 15);
+	cregs[0]  &= ~0x0000ee70UL;	/* disable all external interrupts */
+	cregs[6]  &= ~0xff000000UL;	/* disable all I/O interrupts */
+	cregs[14] &= ~0x1f000000UL;	/* disable most machine checks */
+	__ctl_load(cregs, 0, 15);
+	clear_cpu_flag(CIF_NOHZ_DELAY);
+	return 0;
+}
+
+void __cpu_die(unsigned int cpu)
+{
+	struct pcpu *pcpu;
+
+	/* Wait until target cpu is down */
+	pcpu = pcpu_devices + cpu;
+	while (!pcpu_stopped(pcpu))
+		cpu_relax();
+	pcpu_free_lowcore(pcpu);
+	cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));
+	cpumask_clear_cpu(cpu, &init_mm.context.cpu_attach_mask);
+}
+
+void __noreturn cpu_die(void)
+{
+	idle_task_exit();
+	__bpon();
+	pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
+	for (;;) ;
+}
+
+void __init smp_fill_possible_mask(void)
+{
+	unsigned int possible, sclp_max, cpu;
+
+	sclp_max = max(sclp.mtid, sclp.mtid_cp) + 1;
+	sclp_max = min(smp_max_threads, sclp_max);
+	sclp_max = (sclp.max_cores * sclp_max) ?: nr_cpu_ids;
+	possible = setup_possible_cpus ?: nr_cpu_ids;
+	possible = min(possible, sclp_max);
+	for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
+		set_cpu_possible(cpu, true);
+}
+
+void __init smp_prepare_cpus(unsigned int max_cpus)
+{
+	/* request the 0x1201 emergency signal external interrupt */
+	if (register_external_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt))
+		panic("Couldn't request external interrupt 0x1201");
+	/* request the 0x1202 external call external interrupt */
+	if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt))
+		panic("Couldn't request external interrupt 0x1202");
+}
+
+void __init smp_prepare_boot_cpu(void)
+{
+	struct pcpu *pcpu = pcpu_devices;
+
+	WARN_ON(!cpu_present(0) || !cpu_online(0));
+	pcpu->state = CPU_STATE_CONFIGURED;
+	S390_lowcore.percpu_offset = __per_cpu_offset[0];
+	smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
+}
+
+void __init smp_setup_processor_id(void)
+{
+	pcpu_devices[0].address = stap();
+	S390_lowcore.cpu_nr = 0;
+	S390_lowcore.spinlock_lockval = arch_spin_lockval(0);
+	S390_lowcore.spinlock_index = 0;
+}
+
+/*
+ * the frequency of the profiling timer can be changed
+ * by writing a multiplier value into /proc/profile.
+ *
+ * usually you want to run this on all CPUs ;)
+ */
+int setup_profiling_timer(unsigned int multiplier)
+{
+	return 0;
+}
+
+static ssize_t cpu_configure_show(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	ssize_t count;
+
+	mutex_lock(&smp_cpu_state_mutex);
+	count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
+	mutex_unlock(&smp_cpu_state_mutex);
+	return count;
+}
+
+static ssize_t cpu_configure_store(struct device *dev,
+				   struct device_attribute *attr,
+				   const char *buf, size_t count)
+{
+	struct pcpu *pcpu;
+	int cpu, val, rc, i;
+	char delim;
+
+	if (sscanf(buf, "%d %c", &val, &delim) != 1)
+		return -EINVAL;
+	if (val != 0 && val != 1)
+		return -EINVAL;
+	cpus_read_lock();
+	mutex_lock(&smp_cpu_state_mutex);
+	rc = -EBUSY;
+	/* disallow configuration changes of online cpus and cpu 0 */
+	cpu = dev->id;
+	cpu = smp_get_base_cpu(cpu);
+	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_core_deconfigure(pcpu->address >> smp_cpu_mt_shift);
+		if (rc)
+			break;
+		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_core_configure(pcpu->address >> smp_cpu_mt_shift);
+		if (rc)
+			break;
+		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:
+		break;
+	}
+out:
+	mutex_unlock(&smp_cpu_state_mutex);
+	cpus_read_unlock();
+	return rc ? rc : count;
+}
+static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
+
+static ssize_t show_cpu_address(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
+}
+static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
+
+static struct attribute *cpu_common_attrs[] = {
+	&dev_attr_configure.attr,
+	&dev_attr_address.attr,
+	NULL,
+};
+
+static struct attribute_group cpu_common_attr_group = {
+	.attrs = cpu_common_attrs,
+};
+
+static struct attribute *cpu_online_attrs[] = {
+	&dev_attr_idle_count.attr,
+	&dev_attr_idle_time_us.attr,
+	NULL,
+};
+
+static struct attribute_group cpu_online_attr_group = {
+	.attrs = cpu_online_attrs,
+};
+
+static int smp_cpu_online(unsigned int cpu)
+{
+	struct device *s = &per_cpu(cpu_device, cpu)->dev;
+
+	return sysfs_create_group(&s->kobj, &cpu_online_attr_group);
+}
+
+static int smp_cpu_pre_down(unsigned int cpu)
+{
+	struct device *s = &per_cpu(cpu_device, cpu)->dev;
+
+	sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
+	return 0;
+}
+
+static int smp_add_present_cpu(int cpu)
+{
+	struct device *s;
+	struct cpu *c;
+	int rc;
+
+	c = kzalloc(sizeof(*c), GFP_KERNEL);
+	if (!c)
+		return -ENOMEM;
+	per_cpu(cpu_device, cpu) = c;
+	s = &c->dev;
+	c->hotpluggable = 1;
+	rc = register_cpu(c, cpu);
+	if (rc)
+		goto out;
+	rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
+	if (rc)
+		goto out_cpu;
+	rc = topology_cpu_init(c);
+	if (rc)
+		goto out_topology;
+	return 0;
+
+out_topology:
+	sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
+out_cpu:
+	unregister_cpu(c);
+out:
+	return rc;
+}
+
+int __ref smp_rescan_cpus(void)
+{
+	struct sclp_core_info *info;
+	int nr;
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+	smp_get_core_info(info, 0);
+	nr = __smp_rescan_cpus(info, false);
+	kfree(info);
+	if (nr)
+		topology_schedule_update();
+	return 0;
+}
+
+static ssize_t __ref rescan_store(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf,
+				  size_t count)
+{
+	int rc;
+
+	rc = lock_device_hotplug_sysfs();
+	if (rc)
+		return rc;
+	rc = smp_rescan_cpus();
+	unlock_device_hotplug();
+	return rc ? rc : count;
+}
+static DEVICE_ATTR_WO(rescan);
+
+static int __init s390_smp_init(void)
+{
+	int cpu, rc = 0;
+
+	rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
+	if (rc)
+		return rc;
+	for_each_present_cpu(cpu) {
+		rc = smp_add_present_cpu(cpu);
+		if (rc)
+			goto out;
+	}
+
+	rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "s390/smp:online",
+			       smp_cpu_online, smp_cpu_pre_down);
+	rc = rc <= 0 ? rc : 0;
+out:
+	return rc;
+}
+subsys_initcall(s390_smp_init);
+
+static __always_inline void set_new_lowcore(struct lowcore *lc)
+{
+	union register_pair dst, src;
+	u32 pfx;
+
+	src.even = (unsigned long) &S390_lowcore;
+	src.odd  = sizeof(S390_lowcore);
+	dst.even = (unsigned long) lc;
+	dst.odd  = sizeof(*lc);
+	pfx = __pa(lc);
+
+	asm volatile(
+		"	mvcl	%[dst],%[src]\n"
+		"	spx	%[pfx]\n"
+		: [dst] "+&d" (dst.pair), [src] "+&d" (src.pair)
+		: [pfx] "Q" (pfx)
+		: "memory", "cc");
+}
+
+int __init smp_reinit_ipl_cpu(void)
+{
+	unsigned long async_stack, nodat_stack, mcck_stack;
+	struct lowcore *lc, *lc_ipl;
+	unsigned long flags, cr0;
+	u64 mcesad;
+
+	lc_ipl = lowcore_ptr[0];
+	lc = (struct lowcore *)	__get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
+	nodat_stack = __get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER);
+	async_stack = stack_alloc();
+	mcck_stack = stack_alloc();
+	if (!lc || !nodat_stack || !async_stack || !mcck_stack || nmi_alloc_mcesa(&mcesad))
+		panic("Couldn't allocate memory");
+
+	local_irq_save(flags);
+	local_mcck_disable();
+	set_new_lowcore(lc);
+	S390_lowcore.nodat_stack = nodat_stack + STACK_INIT_OFFSET;
+	S390_lowcore.async_stack = async_stack + STACK_INIT_OFFSET;
+	S390_lowcore.mcck_stack = mcck_stack + STACK_INIT_OFFSET;
+	__ctl_store(cr0, 0, 0);
+	__ctl_clear_bit(0, 28); /* disable lowcore protection */
+	S390_lowcore.mcesad = mcesad;
+	__ctl_load(cr0, 0, 0);
+	if (abs_lowcore_map(0, lc, false))
+		panic("Couldn't remap absolute lowcore");
+	lowcore_ptr[0] = lc;
+	local_mcck_enable();
+	local_irq_restore(flags);
+
+	free_pages(lc_ipl->async_stack - STACK_INIT_OFFSET, THREAD_SIZE_ORDER);
+	memblock_free_late(__pa(lc_ipl->mcck_stack - STACK_INIT_OFFSET), THREAD_SIZE);
+	memblock_free_late(__pa(lc_ipl), sizeof(*lc_ipl));
+
+	return 0;
+}