| // 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() < 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(); |
| } |