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-rw-r--r--arch/parisc/kernel/smp.c517
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diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
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+++ b/arch/parisc/kernel/smp.c
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+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+** SMP Support
+**
+** Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
+** Copyright (C) 1999 David Mosberger-Tang <davidm@hpl.hp.com>
+** Copyright (C) 2001,2004 Grant Grundler <grundler@parisc-linux.org>
+**
+** Lots of stuff stolen from arch/alpha/kernel/smp.c
+** ...and then parisc stole from arch/ia64/kernel/smp.c. Thanks David! :^)
+**
+** Thanks to John Curry and Ullas Ponnadi. I learned a lot from their work.
+** -grant (1/12/2001)
+**
+*/
+#include <linux/types.h>
+#include <linux/spinlock.h>
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sched/mm.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/smp.h>
+#include <linux/kernel_stat.h>
+#include <linux/mm.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/bitops.h>
+#include <linux/ftrace.h>
+#include <linux/cpu.h>
+#include <linux/kgdb.h>
+#include <linux/sched/hotplug.h>
+
+#include <linux/atomic.h>
+#include <asm/current.h>
+#include <asm/delay.h>
+#include <asm/tlbflush.h>
+
+#include <asm/io.h>
+#include <asm/irq.h> /* for CPU_IRQ_REGION and friends */
+#include <asm/mmu_context.h>
+#include <asm/page.h>
+#include <asm/processor.h>
+#include <asm/ptrace.h>
+#include <asm/unistd.h>
+#include <asm/cacheflush.h>
+
+#undef DEBUG_SMP
+#ifdef DEBUG_SMP
+static int smp_debug_lvl = 0;
+#define smp_debug(lvl, printargs...) \
+ if (lvl >= smp_debug_lvl) \
+ printk(printargs);
+#else
+#define smp_debug(lvl, ...) do { } while(0)
+#endif /* DEBUG_SMP */
+
+volatile struct task_struct *smp_init_current_idle_task;
+
+/* track which CPU is booting */
+static volatile int cpu_now_booting;
+
+static DEFINE_PER_CPU(spinlock_t, ipi_lock);
+
+enum ipi_message_type {
+ IPI_NOP=0,
+ IPI_RESCHEDULE=1,
+ IPI_CALL_FUNC,
+ IPI_CPU_START,
+ IPI_CPU_STOP,
+ IPI_CPU_TEST,
+#ifdef CONFIG_KGDB
+ IPI_ENTER_KGDB,
+#endif
+};
+
+
+/********** SMP inter processor interrupt and communication routines */
+
+#undef PER_CPU_IRQ_REGION
+#ifdef PER_CPU_IRQ_REGION
+/* XXX REVISIT Ignore for now.
+** *May* need this "hook" to register IPI handler
+** once we have perCPU ExtIntr switch tables.
+*/
+static void
+ipi_init(int cpuid)
+{
+#error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
+
+ if(cpu_online(cpuid) )
+ {
+ switch_to_idle_task(current);
+ }
+
+ return;
+}
+#endif
+
+
+/*
+** Yoink this CPU from the runnable list...
+**
+*/
+static void
+halt_processor(void)
+{
+ /* REVISIT : redirect I/O Interrupts to another CPU? */
+ /* REVISIT : does PM *know* this CPU isn't available? */
+ set_cpu_online(smp_processor_id(), false);
+ local_irq_disable();
+ __pdc_cpu_rendezvous();
+ for (;;)
+ ;
+}
+
+
+irqreturn_t __irq_entry
+ipi_interrupt(int irq, void *dev_id)
+{
+ int this_cpu = smp_processor_id();
+ struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu);
+ unsigned long ops;
+ unsigned long flags;
+
+ for (;;) {
+ spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
+ spin_lock_irqsave(lock, flags);
+ ops = p->pending_ipi;
+ p->pending_ipi = 0;
+ spin_unlock_irqrestore(lock, flags);
+
+ mb(); /* Order bit clearing and data access. */
+
+ if (!ops)
+ break;
+
+ while (ops) {
+ unsigned long which = ffz(~ops);
+
+ ops &= ~(1 << which);
+
+ switch (which) {
+ case IPI_NOP:
+ smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
+ break;
+
+ case IPI_RESCHEDULE:
+ smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
+ inc_irq_stat(irq_resched_count);
+ scheduler_ipi();
+ break;
+
+ case IPI_CALL_FUNC:
+ smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
+ inc_irq_stat(irq_call_count);
+ generic_smp_call_function_interrupt();
+ break;
+
+ case IPI_CPU_START:
+ smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
+ break;
+
+ case IPI_CPU_STOP:
+ smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
+ halt_processor();
+ break;
+
+ case IPI_CPU_TEST:
+ smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
+ break;
+#ifdef CONFIG_KGDB
+ case IPI_ENTER_KGDB:
+ smp_debug(100, KERN_DEBUG "CPU%d ENTER_KGDB\n", this_cpu);
+ kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
+ break;
+#endif
+ default:
+ printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
+ this_cpu, which);
+ return IRQ_NONE;
+ } /* Switch */
+
+ /* before doing more, let in any pending interrupts */
+ if (ops) {
+ local_irq_enable();
+ local_irq_disable();
+ }
+ } /* while (ops) */
+ }
+ return IRQ_HANDLED;
+}
+
+
+static inline void
+ipi_send(int cpu, enum ipi_message_type op)
+{
+ struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu);
+ spinlock_t *lock = &per_cpu(ipi_lock, cpu);
+ unsigned long flags;
+
+ spin_lock_irqsave(lock, flags);
+ p->pending_ipi |= 1 << op;
+ gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa);
+ spin_unlock_irqrestore(lock, flags);
+}
+
+static void
+send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op)
+{
+ int cpu;
+
+ for_each_cpu(cpu, mask)
+ ipi_send(cpu, op);
+}
+
+static inline void
+send_IPI_single(int dest_cpu, enum ipi_message_type op)
+{
+ BUG_ON(dest_cpu == NO_PROC_ID);
+
+ ipi_send(dest_cpu, op);
+}
+
+static inline void
+send_IPI_allbutself(enum ipi_message_type op)
+{
+ int i;
+
+ preempt_disable();
+ for_each_online_cpu(i) {
+ if (i != smp_processor_id())
+ send_IPI_single(i, op);
+ }
+ preempt_enable();
+}
+
+#ifdef CONFIG_KGDB
+void kgdb_roundup_cpus(void)
+{
+ send_IPI_allbutself(IPI_ENTER_KGDB);
+}
+#endif
+
+inline void
+smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); }
+
+void
+smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
+
+void
+smp_send_all_nop(void)
+{
+ send_IPI_allbutself(IPI_NOP);
+}
+
+void arch_send_call_function_ipi_mask(const struct cpumask *mask)
+{
+ send_IPI_mask(mask, IPI_CALL_FUNC);
+}
+
+void arch_send_call_function_single_ipi(int cpu)
+{
+ send_IPI_single(cpu, IPI_CALL_FUNC);
+}
+
+/*
+ * Called by secondaries to update state and initialize CPU registers.
+ */
+static void
+smp_cpu_init(int cpunum)
+{
+ extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */
+ extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
+
+ /* Set modes and Enable floating point coprocessor */
+ init_per_cpu(cpunum);
+
+ disable_sr_hashing();
+
+ mb();
+
+ /* Well, support 2.4 linux scheme as well. */
+ if (cpu_online(cpunum)) {
+ extern void machine_halt(void); /* arch/parisc.../process.c */
+
+ printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
+ machine_halt();
+ }
+
+ notify_cpu_starting(cpunum);
+
+ set_cpu_online(cpunum, true);
+
+ /* Initialise the idle task for this CPU */
+ mmgrab(&init_mm);
+ current->active_mm = &init_mm;
+ BUG_ON(current->mm);
+ enter_lazy_tlb(&init_mm, current);
+
+ init_IRQ(); /* make sure no IRQs are enabled or pending */
+ start_cpu_itimer();
+}
+
+
+/*
+ * Slaves start using C here. Indirectly called from smp_slave_stext.
+ * Do what start_kernel() and main() do for boot strap processor (aka monarch)
+ */
+void smp_callin(unsigned long pdce_proc)
+{
+ int slave_id = cpu_now_booting;
+
+#ifdef CONFIG_64BIT
+ WARN_ON(((unsigned long)(PAGE0->mem_pdc_hi) << 32
+ | PAGE0->mem_pdc) != pdce_proc);
+#endif
+
+ smp_cpu_init(slave_id);
+
+ flush_cache_all_local(); /* start with known state */
+ flush_tlb_all_local(NULL);
+
+ local_irq_enable(); /* Interrupts have been off until now */
+
+ cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
+
+ /* NOTREACHED */
+ panic("smp_callin() AAAAaaaaahhhh....\n");
+}
+
+/*
+ * Bring one cpu online.
+ */
+static int smp_boot_one_cpu(int cpuid, struct task_struct *idle)
+{
+ const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid);
+ long timeout;
+
+#ifdef CONFIG_HOTPLUG_CPU
+ int i;
+
+ /* reset irq statistics for this CPU */
+ memset(&per_cpu(irq_stat, cpuid), 0, sizeof(irq_cpustat_t));
+ for (i = 0; i < NR_IRQS; i++) {
+ struct irq_desc *desc = irq_to_desc(i);
+
+ if (desc && desc->kstat_irqs)
+ *per_cpu_ptr(desc->kstat_irqs, cpuid) = 0;
+ }
+#endif
+
+ /* wait until last booting CPU has started. */
+ while (cpu_now_booting)
+ ;
+
+ /* Let _start know what logical CPU we're booting
+ ** (offset into init_tasks[],cpu_data[])
+ */
+ cpu_now_booting = cpuid;
+
+ /*
+ ** boot strap code needs to know the task address since
+ ** it also contains the process stack.
+ */
+ smp_init_current_idle_task = idle ;
+ mb();
+
+ printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa);
+
+ /*
+ ** This gets PDC to release the CPU from a very tight loop.
+ **
+ ** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
+ ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which
+ ** is executed after receiving the rendezvous signal (an interrupt to
+ ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the
+ ** contents of memory are valid."
+ */
+ gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa);
+ mb();
+
+ /*
+ * OK, wait a bit for that CPU to finish staggering about.
+ * Slave will set a bit when it reaches smp_cpu_init().
+ * Once the "monarch CPU" sees the bit change, it can move on.
+ */
+ for (timeout = 0; timeout < 10000; timeout++) {
+ if(cpu_online(cpuid)) {
+ /* Which implies Slave has started up */
+ cpu_now_booting = 0;
+ goto alive ;
+ }
+ udelay(100);
+ barrier();
+ }
+ printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
+ return -1;
+
+alive:
+ /* Remember the Slave data */
+ smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
+ cpuid, timeout * 100);
+ return 0;
+}
+
+void __init smp_prepare_boot_cpu(void)
+{
+ int bootstrap_processor = per_cpu(cpu_data, 0).cpuid;
+
+ /* Setup BSP mappings */
+ printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor);
+
+ set_cpu_online(bootstrap_processor, true);
+ set_cpu_present(bootstrap_processor, true);
+}
+
+
+
+/*
+** inventory.c:do_inventory() hasn't yet been run and thus we
+** don't 'discover' the additional CPUs until later.
+*/
+void __init smp_prepare_cpus(unsigned int max_cpus)
+{
+ int cpu;
+
+ for_each_possible_cpu(cpu)
+ spin_lock_init(&per_cpu(ipi_lock, cpu));
+
+ init_cpu_present(cpumask_of(0));
+}
+
+
+void __init smp_cpus_done(unsigned int cpu_max)
+{
+}
+
+
+int __cpu_up(unsigned int cpu, struct task_struct *tidle)
+{
+ if (cpu_online(cpu))
+ return 0;
+
+ if (num_online_cpus() < nr_cpu_ids &&
+ num_online_cpus() < setup_max_cpus &&
+ smp_boot_one_cpu(cpu, tidle))
+ return -EIO;
+
+ return cpu_online(cpu) ? 0 : -EIO;
+}
+
+/*
+ * __cpu_disable runs on the processor to be shutdown.
+ */
+int __cpu_disable(void)
+{
+#ifdef CONFIG_HOTPLUG_CPU
+ unsigned int cpu = smp_processor_id();
+
+ remove_cpu_topology(cpu);
+
+ /*
+ * Take this CPU offline. Once we clear this, we can't return,
+ * and we must not schedule until we're ready to give up the cpu.
+ */
+ set_cpu_online(cpu, false);
+
+ /* Find a new timesync master */
+ if (cpu == time_keeper_id) {
+ time_keeper_id = cpumask_first(cpu_online_mask);
+ pr_info("CPU %d is now promoted to time-keeper master\n", time_keeper_id);
+ }
+
+ disable_percpu_irq(IPI_IRQ);
+
+ irq_migrate_all_off_this_cpu();
+
+ flush_cache_all_local();
+ flush_tlb_all_local(NULL);
+
+ /* disable all irqs, including timer irq */
+ local_irq_disable();
+
+ /* wait for next timer irq ... */
+ mdelay(1000/HZ+100);
+
+ /* ... and then clear all pending external irqs */
+ set_eiem(0);
+ mtctl(~0UL, CR_EIRR);
+ mfctl(CR_EIRR);
+ mtctl(0, CR_EIRR);
+#endif
+ return 0;
+}
+
+/*
+ * called on the thread which is asking for a CPU to be shutdown -
+ * waits until shutdown has completed, or it is timed out.
+ */
+void __cpu_die(unsigned int cpu)
+{
+ pdc_cpu_rendezvous_lock();
+
+ if (!cpu_wait_death(cpu, 5)) {
+ pr_crit("CPU%u: cpu didn't die\n", cpu);
+ return;
+ }
+ pr_info("CPU%u: is shutting down\n", cpu);
+
+ /* set task's state to interruptible sleep */
+ set_current_state(TASK_INTERRUPTIBLE);
+ schedule_timeout((IS_ENABLED(CONFIG_64BIT) ? 8:2) * HZ);
+
+ pdc_cpu_rendezvous_unlock();
+}