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- // SPDX-License-Identifier: GPL-2.0-or-later
- /*
- ** SMP Support
- **
- ** Copyright (C) 1999 Walt Drummond <[email protected]>
- ** Copyright (C) 1999 David Mosberger-Tang <[email protected]>
- ** Copyright (C) 2001,2004 Grant Grundler <[email protected]>
- **
- ** 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();
- }
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