diff options
Diffstat (limited to 'arch/arm/kernel/smp.c')
| -rw-r--r-- | arch/arm/kernel/smp.c | 856 |
1 files changed, 856 insertions, 0 deletions
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c new file mode 100644 index 000000000..978db2d96 --- /dev/null +++ b/arch/arm/kernel/smp.c @@ -0,0 +1,856 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * linux/arch/arm/kernel/smp.c + * + * Copyright (C) 2002 ARM Limited, All Rights Reserved. + */ +#include <linux/module.h> +#include <linux/delay.h> +#include <linux/init.h> +#include <linux/spinlock.h> +#include <linux/sched/mm.h> +#include <linux/sched/hotplug.h> +#include <linux/sched/task_stack.h> +#include <linux/interrupt.h> +#include <linux/cache.h> +#include <linux/profile.h> +#include <linux/errno.h> +#include <linux/mm.h> +#include <linux/err.h> +#include <linux/cpu.h> +#include <linux/seq_file.h> +#include <linux/irq.h> +#include <linux/nmi.h> +#include <linux/percpu.h> +#include <linux/clockchips.h> +#include <linux/completion.h> +#include <linux/cpufreq.h> +#include <linux/irq_work.h> +#include <linux/kernel_stat.h> + +#include <linux/atomic.h> +#include <asm/bugs.h> +#include <asm/smp.h> +#include <asm/cacheflush.h> +#include <asm/cpu.h> +#include <asm/cputype.h> +#include <asm/exception.h> +#include <asm/idmap.h> +#include <asm/topology.h> +#include <asm/mmu_context.h> +#include <asm/procinfo.h> +#include <asm/processor.h> +#include <asm/sections.h> +#include <asm/tlbflush.h> +#include <asm/ptrace.h> +#include <asm/smp_plat.h> +#include <asm/virt.h> +#include <asm/mach/arch.h> +#include <asm/mpu.h> + +#define CREATE_TRACE_POINTS +#include <trace/events/ipi.h> + +/* + * as from 2.5, kernels no longer have an init_tasks structure + * so we need some other way of telling a new secondary core + * where to place its SVC stack + */ +struct secondary_data secondary_data; + +enum ipi_msg_type { + IPI_WAKEUP, + IPI_TIMER, + IPI_RESCHEDULE, + IPI_CALL_FUNC, + IPI_CPU_STOP, + IPI_IRQ_WORK, + IPI_COMPLETION, + NR_IPI, + /* + * CPU_BACKTRACE is special and not included in NR_IPI + * or tracable with trace_ipi_* + */ + IPI_CPU_BACKTRACE = NR_IPI, + /* + * SGI8-15 can be reserved by secure firmware, and thus may + * not be usable by the kernel. Please keep the above limited + * to at most 8 entries. + */ + MAX_IPI +}; + +static int ipi_irq_base __read_mostly; +static int nr_ipi __read_mostly = NR_IPI; +static struct irq_desc *ipi_desc[MAX_IPI] __read_mostly; + +static void ipi_setup(int cpu); + +static DECLARE_COMPLETION(cpu_running); + +static struct smp_operations smp_ops __ro_after_init; + +void __init smp_set_ops(const struct smp_operations *ops) +{ + if (ops) + smp_ops = *ops; +}; + +static unsigned long get_arch_pgd(pgd_t *pgd) +{ +#ifdef CONFIG_ARM_LPAE + return __phys_to_pfn(virt_to_phys(pgd)); +#else + return virt_to_phys(pgd); +#endif +} + +#if defined(CONFIG_BIG_LITTLE) && defined(CONFIG_HARDEN_BRANCH_PREDICTOR) +static int secondary_biglittle_prepare(unsigned int cpu) +{ + if (!cpu_vtable[cpu]) + cpu_vtable[cpu] = kzalloc(sizeof(*cpu_vtable[cpu]), GFP_KERNEL); + + return cpu_vtable[cpu] ? 0 : -ENOMEM; +} + +static void secondary_biglittle_init(void) +{ + init_proc_vtable(lookup_processor(read_cpuid_id())->proc); +} +#else +static int secondary_biglittle_prepare(unsigned int cpu) +{ + return 0; +} + +static void secondary_biglittle_init(void) +{ +} +#endif + +int __cpu_up(unsigned int cpu, struct task_struct *idle) +{ + int ret; + + if (!smp_ops.smp_boot_secondary) + return -ENOSYS; + + ret = secondary_biglittle_prepare(cpu); + if (ret) + return ret; + + /* + * We need to tell the secondary core where to find + * its stack and the page tables. + */ + secondary_data.stack = task_stack_page(idle) + THREAD_START_SP; +#ifdef CONFIG_ARM_MPU + secondary_data.mpu_rgn_info = &mpu_rgn_info; +#endif + +#ifdef CONFIG_MMU + secondary_data.pgdir = virt_to_phys(idmap_pgd); + secondary_data.swapper_pg_dir = get_arch_pgd(swapper_pg_dir); +#endif + secondary_data.task = idle; + sync_cache_w(&secondary_data); + + /* + * Now bring the CPU into our world. + */ + ret = smp_ops.smp_boot_secondary(cpu, idle); + if (ret == 0) { + /* + * CPU was successfully started, wait for it + * to come online or time out. + */ + wait_for_completion_timeout(&cpu_running, + msecs_to_jiffies(1000)); + + if (!cpu_online(cpu)) { + pr_crit("CPU%u: failed to come online\n", cpu); + ret = -EIO; + } + } else { + pr_err("CPU%u: failed to boot: %d\n", cpu, ret); + } + + + memset(&secondary_data, 0, sizeof(secondary_data)); + return ret; +} + +/* platform specific SMP operations */ +void __init smp_init_cpus(void) +{ + if (smp_ops.smp_init_cpus) + smp_ops.smp_init_cpus(); +} + +int platform_can_secondary_boot(void) +{ + return !!smp_ops.smp_boot_secondary; +} + +int platform_can_cpu_hotplug(void) +{ +#ifdef CONFIG_HOTPLUG_CPU + if (smp_ops.cpu_kill) + return 1; +#endif + + return 0; +} + +#ifdef CONFIG_HOTPLUG_CPU +static int platform_cpu_kill(unsigned int cpu) +{ + if (smp_ops.cpu_kill) + return smp_ops.cpu_kill(cpu); + return 1; +} + +static int platform_cpu_disable(unsigned int cpu) +{ + if (smp_ops.cpu_disable) + return smp_ops.cpu_disable(cpu); + + return 0; +} + +int platform_can_hotplug_cpu(unsigned int cpu) +{ + /* cpu_die must be specified to support hotplug */ + if (!smp_ops.cpu_die) + return 0; + + if (smp_ops.cpu_can_disable) + return smp_ops.cpu_can_disable(cpu); + + /* + * By default, allow disabling all CPUs except the first one, + * since this is special on a lot of platforms, e.g. because + * of clock tick interrupts. + */ + return cpu != 0; +} + +static void ipi_teardown(int cpu) +{ + int i; + + if (WARN_ON_ONCE(!ipi_irq_base)) + return; + + for (i = 0; i < nr_ipi; i++) + disable_percpu_irq(ipi_irq_base + i); +} + +/* + * __cpu_disable runs on the processor to be shutdown. + */ +int __cpu_disable(void) +{ + unsigned int cpu = smp_processor_id(); + int ret; + + ret = platform_cpu_disable(cpu); + if (ret) + return ret; + +#ifdef CONFIG_GENERIC_ARCH_TOPOLOGY + remove_cpu_topology(cpu); +#endif + + /* + * 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); + ipi_teardown(cpu); + + /* + * OK - migrate IRQs away from this CPU + */ + irq_migrate_all_off_this_cpu(); + + /* + * Flush user cache and TLB mappings, and then remove this CPU + * from the vm mask set of all processes. + * + * Caches are flushed to the Level of Unification Inner Shareable + * to write-back dirty lines to unified caches shared by all CPUs. + */ + flush_cache_louis(); + local_flush_tlb_all(); + + 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) +{ + if (!cpu_wait_death(cpu, 5)) { + pr_err("CPU%u: cpu didn't die\n", cpu); + return; + } + pr_debug("CPU%u: shutdown\n", cpu); + + clear_tasks_mm_cpumask(cpu); + /* + * platform_cpu_kill() is generally expected to do the powering off + * and/or cutting of clocks to the dying CPU. Optionally, this may + * be done by the CPU which is dying in preference to supporting + * this call, but that means there is _no_ synchronisation between + * the requesting CPU and the dying CPU actually losing power. + */ + if (!platform_cpu_kill(cpu)) + pr_err("CPU%u: unable to kill\n", cpu); +} + +/* + * Called from the idle thread for the CPU which has been shutdown. + * + * Note that we disable IRQs here, but do not re-enable them + * before returning to the caller. This is also the behaviour + * of the other hotplug-cpu capable cores, so presumably coming + * out of idle fixes this. + */ +void arch_cpu_idle_dead(void) +{ + unsigned int cpu = smp_processor_id(); + + idle_task_exit(); + + local_irq_disable(); + + /* + * Flush the data out of the L1 cache for this CPU. This must be + * before the completion to ensure that data is safely written out + * before platform_cpu_kill() gets called - which may disable + * *this* CPU and power down its cache. + */ + flush_cache_louis(); + + /* + * Tell __cpu_die() that this CPU is now safe to dispose of. Once + * this returns, power and/or clocks can be removed at any point + * from this CPU and its cache by platform_cpu_kill(). + */ + (void)cpu_report_death(); + + /* + * Ensure that the cache lines associated with that completion are + * written out. This covers the case where _this_ CPU is doing the + * powering down, to ensure that the completion is visible to the + * CPU waiting for this one. + */ + flush_cache_louis(); + + /* + * The actual CPU shutdown procedure is at least platform (if not + * CPU) specific. This may remove power, or it may simply spin. + * + * Platforms are generally expected *NOT* to return from this call, + * although there are some which do because they have no way to + * power down the CPU. These platforms are the _only_ reason we + * have a return path which uses the fragment of assembly below. + * + * The return path should not be used for platforms which can + * power off the CPU. + */ + if (smp_ops.cpu_die) + smp_ops.cpu_die(cpu); + + pr_warn("CPU%u: smp_ops.cpu_die() returned, trying to resuscitate\n", + cpu); + + /* + * Do not return to the idle loop - jump back to the secondary + * cpu initialisation. There's some initialisation which needs + * to be repeated to undo the effects of taking the CPU offline. + */ + __asm__("mov sp, %0\n" + " mov fp, #0\n" + " mov r0, %1\n" + " b secondary_start_kernel" + : + : "r" (task_stack_page(current) + THREAD_SIZE - 8), + "r" (current) + : "r0"); +} +#endif /* CONFIG_HOTPLUG_CPU */ + +/* + * Called by both boot and secondaries to move global data into + * per-processor storage. + */ +static void smp_store_cpu_info(unsigned int cpuid) +{ + struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid); + + cpu_info->loops_per_jiffy = loops_per_jiffy; + cpu_info->cpuid = read_cpuid_id(); + + store_cpu_topology(cpuid); + check_cpu_icache_size(cpuid); +} + +static void set_current(struct task_struct *cur) +{ + /* Set TPIDRURO */ + asm("mcr p15, 0, %0, c13, c0, 3" :: "r"(cur) : "memory"); +} + +/* + * This is the secondary CPU boot entry. We're using this CPUs + * idle thread stack, but a set of temporary page tables. + */ +asmlinkage void secondary_start_kernel(struct task_struct *task) +{ + struct mm_struct *mm = &init_mm; + unsigned int cpu; + + set_current(task); + + secondary_biglittle_init(); + + /* + * The identity mapping is uncached (strongly ordered), so + * switch away from it before attempting any exclusive accesses. + */ + cpu_switch_mm(mm->pgd, mm); + local_flush_bp_all(); + enter_lazy_tlb(mm, current); + local_flush_tlb_all(); + + /* + * All kernel threads share the same mm context; grab a + * reference and switch to it. + */ + cpu = smp_processor_id(); + mmgrab(mm); + current->active_mm = mm; + cpumask_set_cpu(cpu, mm_cpumask(mm)); + + cpu_init(); + +#ifndef CONFIG_MMU + setup_vectors_base(); +#endif + pr_debug("CPU%u: Booted secondary processor\n", cpu); + + trace_hardirqs_off(); + + /* + * Give the platform a chance to do its own initialisation. + */ + if (smp_ops.smp_secondary_init) + smp_ops.smp_secondary_init(cpu); + + notify_cpu_starting(cpu); + + ipi_setup(cpu); + + calibrate_delay(); + + smp_store_cpu_info(cpu); + + /* + * OK, now it's safe to let the boot CPU continue. Wait for + * the CPU migration code to notice that the CPU is online + * before we continue - which happens after __cpu_up returns. + */ + set_cpu_online(cpu, true); + + check_other_bugs(); + + complete(&cpu_running); + + local_irq_enable(); + local_fiq_enable(); + local_abt_enable(); + + /* + * OK, it's off to the idle thread for us + */ + cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); +} + +void __init smp_cpus_done(unsigned int max_cpus) +{ + int cpu; + unsigned long bogosum = 0; + + for_each_online_cpu(cpu) + bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy; + + printk(KERN_INFO "SMP: Total of %d processors activated " + "(%lu.%02lu BogoMIPS).\n", + num_online_cpus(), + bogosum / (500000/HZ), + (bogosum / (5000/HZ)) % 100); + + hyp_mode_check(); +} + +void __init smp_prepare_boot_cpu(void) +{ + set_my_cpu_offset(per_cpu_offset(smp_processor_id())); +} + +void __init smp_prepare_cpus(unsigned int max_cpus) +{ + unsigned int ncores = num_possible_cpus(); + + init_cpu_topology(); + + smp_store_cpu_info(smp_processor_id()); + + /* + * are we trying to boot more cores than exist? + */ + if (max_cpus > ncores) + max_cpus = ncores; + if (ncores > 1 && max_cpus) { + /* + * Initialise the present map, which describes the set of CPUs + * actually populated at the present time. A platform should + * re-initialize the map in the platforms smp_prepare_cpus() + * if present != possible (e.g. physical hotplug). + */ + init_cpu_present(cpu_possible_mask); + + /* + * Initialise the SCU if there are more than one CPU + * and let them know where to start. + */ + if (smp_ops.smp_prepare_cpus) + smp_ops.smp_prepare_cpus(max_cpus); + } +} + +static const char *ipi_types[NR_IPI] __tracepoint_string = { + [IPI_WAKEUP] = "CPU wakeup interrupts", + [IPI_TIMER] = "Timer broadcast interrupts", + [IPI_RESCHEDULE] = "Rescheduling interrupts", + [IPI_CALL_FUNC] = "Function call interrupts", + [IPI_CPU_STOP] = "CPU stop interrupts", + [IPI_IRQ_WORK] = "IRQ work interrupts", + [IPI_COMPLETION] = "completion interrupts", +}; + +static void smp_cross_call(const struct cpumask *target, unsigned int ipinr); + +void show_ipi_list(struct seq_file *p, int prec) +{ + unsigned int cpu, i; + + for (i = 0; i < NR_IPI; i++) { + if (!ipi_desc[i]) + continue; + + seq_printf(p, "%*s%u: ", prec - 1, "IPI", i); + + for_each_online_cpu(cpu) + seq_printf(p, "%10u ", irq_desc_kstat_cpu(ipi_desc[i], cpu)); + + seq_printf(p, " %s\n", ipi_types[i]); + } +} + +void arch_send_call_function_ipi_mask(const struct cpumask *mask) +{ + smp_cross_call(mask, IPI_CALL_FUNC); +} + +void arch_send_wakeup_ipi_mask(const struct cpumask *mask) +{ + smp_cross_call(mask, IPI_WAKEUP); +} + +void arch_send_call_function_single_ipi(int cpu) +{ + smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC); +} + +#ifdef CONFIG_IRQ_WORK +void arch_irq_work_raise(void) +{ + if (arch_irq_work_has_interrupt()) + smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK); +} +#endif + +#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST +void tick_broadcast(const struct cpumask *mask) +{ + smp_cross_call(mask, IPI_TIMER); +} +#endif + +static DEFINE_RAW_SPINLOCK(stop_lock); + +/* + * ipi_cpu_stop - handle IPI from smp_send_stop() + */ +static void ipi_cpu_stop(unsigned int cpu) +{ + if (system_state <= SYSTEM_RUNNING) { + raw_spin_lock(&stop_lock); + pr_crit("CPU%u: stopping\n", cpu); + dump_stack(); + raw_spin_unlock(&stop_lock); + } + + set_cpu_online(cpu, false); + + local_fiq_disable(); + local_irq_disable(); + + while (1) { + cpu_relax(); + wfe(); + } +} + +static DEFINE_PER_CPU(struct completion *, cpu_completion); + +int register_ipi_completion(struct completion *completion, int cpu) +{ + per_cpu(cpu_completion, cpu) = completion; + return IPI_COMPLETION; +} + +static void ipi_complete(unsigned int cpu) +{ + complete(per_cpu(cpu_completion, cpu)); +} + +/* + * Main handler for inter-processor interrupts + */ +static void do_handle_IPI(int ipinr) +{ + unsigned int cpu = smp_processor_id(); + + if ((unsigned)ipinr < NR_IPI) + trace_ipi_entry_rcuidle(ipi_types[ipinr]); + + switch (ipinr) { + case IPI_WAKEUP: + break; + +#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST + case IPI_TIMER: + tick_receive_broadcast(); + break; +#endif + + case IPI_RESCHEDULE: + scheduler_ipi(); + break; + + case IPI_CALL_FUNC: + generic_smp_call_function_interrupt(); + break; + + case IPI_CPU_STOP: + ipi_cpu_stop(cpu); + break; + +#ifdef CONFIG_IRQ_WORK + case IPI_IRQ_WORK: + irq_work_run(); + break; +#endif + + case IPI_COMPLETION: + ipi_complete(cpu); + break; + + case IPI_CPU_BACKTRACE: + printk_deferred_enter(); + nmi_cpu_backtrace(get_irq_regs()); + printk_deferred_exit(); + break; + + default: + pr_crit("CPU%u: Unknown IPI message 0x%x\n", + cpu, ipinr); + break; + } + + if ((unsigned)ipinr < NR_IPI) + trace_ipi_exit_rcuidle(ipi_types[ipinr]); +} + +/* Legacy version, should go away once all irqchips have been converted */ +void handle_IPI(int ipinr, struct pt_regs *regs) +{ + struct pt_regs *old_regs = set_irq_regs(regs); + + irq_enter(); + do_handle_IPI(ipinr); + irq_exit(); + + set_irq_regs(old_regs); +} + +static irqreturn_t ipi_handler(int irq, void *data) +{ + do_handle_IPI(irq - ipi_irq_base); + return IRQ_HANDLED; +} + +static void smp_cross_call(const struct cpumask *target, unsigned int ipinr) +{ + trace_ipi_raise_rcuidle(target, ipi_types[ipinr]); + __ipi_send_mask(ipi_desc[ipinr], target); +} + +static void ipi_setup(int cpu) +{ + int i; + + if (WARN_ON_ONCE(!ipi_irq_base)) + return; + + for (i = 0; i < nr_ipi; i++) + enable_percpu_irq(ipi_irq_base + i, 0); +} + +void __init set_smp_ipi_range(int ipi_base, int n) +{ + int i; + + WARN_ON(n < MAX_IPI); + nr_ipi = min(n, MAX_IPI); + + for (i = 0; i < nr_ipi; i++) { + int err; + + err = request_percpu_irq(ipi_base + i, ipi_handler, + "IPI", &irq_stat); + WARN_ON(err); + + ipi_desc[i] = irq_to_desc(ipi_base + i); + irq_set_status_flags(ipi_base + i, IRQ_HIDDEN); + } + + ipi_irq_base = ipi_base; + + /* Setup the boot CPU immediately */ + ipi_setup(smp_processor_id()); +} + +void smp_send_reschedule(int cpu) +{ + smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE); +} + +void smp_send_stop(void) +{ + unsigned long timeout; + struct cpumask mask; + + cpumask_copy(&mask, cpu_online_mask); + cpumask_clear_cpu(smp_processor_id(), &mask); + if (!cpumask_empty(&mask)) + smp_cross_call(&mask, IPI_CPU_STOP); + + /* Wait up to one second for other CPUs to stop */ + timeout = USEC_PER_SEC; + while (num_online_cpus() > 1 && timeout--) + udelay(1); + + if (num_online_cpus() > 1) + pr_warn("SMP: failed to stop secondary CPUs\n"); +} + +/* In case panic() and panic() called at the same time on CPU1 and CPU2, + * and CPU 1 calls panic_smp_self_stop() before crash_smp_send_stop() + * CPU1 can't receive the ipi irqs from CPU2, CPU1 will be always online, + * kdump fails. So split out the panic_smp_self_stop() and add + * set_cpu_online(smp_processor_id(), false). + */ +void panic_smp_self_stop(void) +{ + pr_debug("CPU %u will stop doing anything useful since another CPU has paniced\n", + smp_processor_id()); + set_cpu_online(smp_processor_id(), false); + while (1) + cpu_relax(); +} + +#ifdef CONFIG_CPU_FREQ + +static DEFINE_PER_CPU(unsigned long, l_p_j_ref); +static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq); +static unsigned long global_l_p_j_ref; +static unsigned long global_l_p_j_ref_freq; + +static int cpufreq_callback(struct notifier_block *nb, + unsigned long val, void *data) +{ + struct cpufreq_freqs *freq = data; + struct cpumask *cpus = freq->policy->cpus; + int cpu, first = cpumask_first(cpus); + unsigned int lpj; + + if (freq->flags & CPUFREQ_CONST_LOOPS) + return NOTIFY_OK; + + if (!per_cpu(l_p_j_ref, first)) { + for_each_cpu(cpu, cpus) { + per_cpu(l_p_j_ref, cpu) = + per_cpu(cpu_data, cpu).loops_per_jiffy; + per_cpu(l_p_j_ref_freq, cpu) = freq->old; + } + + if (!global_l_p_j_ref) { + global_l_p_j_ref = loops_per_jiffy; + global_l_p_j_ref_freq = freq->old; + } + } + + if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) || + (val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) { + loops_per_jiffy = cpufreq_scale(global_l_p_j_ref, + global_l_p_j_ref_freq, + freq->new); + + lpj = cpufreq_scale(per_cpu(l_p_j_ref, first), + per_cpu(l_p_j_ref_freq, first), freq->new); + for_each_cpu(cpu, cpus) + per_cpu(cpu_data, cpu).loops_per_jiffy = lpj; + } + return NOTIFY_OK; +} + +static struct notifier_block cpufreq_notifier = { + .notifier_call = cpufreq_callback, +}; + +static int __init register_cpufreq_notifier(void) +{ + return cpufreq_register_notifier(&cpufreq_notifier, + CPUFREQ_TRANSITION_NOTIFIER); +} +core_initcall(register_cpufreq_notifier); + +#endif + +static void raise_nmi(cpumask_t *mask) +{ + __ipi_send_mask(ipi_desc[IPI_CPU_BACKTRACE], mask); +} + +void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self) +{ + nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_nmi); +} |