diff options
Diffstat (limited to 'arch/arm64/kernel/smp.c')
| -rw-r--r-- | arch/arm64/kernel/smp.c | 469 |
1 files changed, 469 insertions, 0 deletions
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c new file mode 100644 index 000000000000..b711525be21f --- /dev/null +++ b/arch/arm64/kernel/smp.c @@ -0,0 +1,469 @@ +/* + * SMP initialisation and IPI support + * Based on arch/arm/kernel/smp.c + * + * Copyright (C) 2012 ARM Ltd. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/delay.h> +#include <linux/init.h> +#include <linux/spinlock.h> +#include <linux/sched.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/smp.h> +#include <linux/seq_file.h> +#include <linux/irq.h> +#include <linux/percpu.h> +#include <linux/clockchips.h> +#include <linux/completion.h> +#include <linux/of.h> + +#include <asm/atomic.h> +#include <asm/cacheflush.h> +#include <asm/cputype.h> +#include <asm/mmu_context.h> +#include <asm/pgtable.h> +#include <asm/pgalloc.h> +#include <asm/processor.h> +#include <asm/sections.h> +#include <asm/tlbflush.h> +#include <asm/ptrace.h> +#include <asm/mmu_context.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; +volatile unsigned long secondary_holding_pen_release = -1; + +enum ipi_msg_type { + IPI_RESCHEDULE, + IPI_CALL_FUNC, + IPI_CALL_FUNC_SINGLE, + IPI_CPU_STOP, +}; + +static DEFINE_RAW_SPINLOCK(boot_lock); + +/* + * Write secondary_holding_pen_release in a way that is guaranteed to be + * visible to all observers, irrespective of whether they're taking part + * in coherency or not. This is necessary for the hotplug code to work + * reliably. + */ +static void __cpuinit write_pen_release(int val) +{ + void *start = (void *)&secondary_holding_pen_release; + unsigned long size = sizeof(secondary_holding_pen_release); + + secondary_holding_pen_release = val; + __flush_dcache_area(start, size); +} + +/* + * Boot a secondary CPU, and assign it the specified idle task. + * This also gives us the initial stack to use for this CPU. + */ +static int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) +{ + unsigned long timeout; + + /* + * Set synchronisation state between this boot processor + * and the secondary one + */ + raw_spin_lock(&boot_lock); + + /* + * Update the pen release flag. + */ + write_pen_release(cpu); + + /* + * Send an event, causing the secondaries to read pen_release. + */ + sev(); + + timeout = jiffies + (1 * HZ); + while (time_before(jiffies, timeout)) { + if (secondary_holding_pen_release == -1UL) + break; + udelay(10); + } + + /* + * Now the secondary core is starting up let it run its + * calibrations, then wait for it to finish + */ + raw_spin_unlock(&boot_lock); + + return secondary_holding_pen_release != -1 ? -ENOSYS : 0; +} + +static DECLARE_COMPLETION(cpu_running); + +int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle) +{ + int 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; + __flush_dcache_area(&secondary_data, sizeof(secondary_data)); + + /* + * Now bring the CPU into our world. + */ + ret = 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); + } + + secondary_data.stack = NULL; + + return ret; +} + +/* + * This is the secondary CPU boot entry. We're using this CPUs + * idle thread stack, but a set of temporary page tables. + */ +asmlinkage void __cpuinit secondary_start_kernel(void) +{ + struct mm_struct *mm = &init_mm; + unsigned int cpu = smp_processor_id(); + + printk("CPU%u: Booted secondary processor\n", cpu); + + /* + * All kernel threads share the same mm context; grab a + * reference and switch to it. + */ + atomic_inc(&mm->mm_count); + current->active_mm = mm; + cpumask_set_cpu(cpu, mm_cpumask(mm)); + + /* + * TTBR0 is only used for the identity mapping at this stage. Make it + * point to zero page to avoid speculatively fetching new entries. + */ + cpu_set_reserved_ttbr0(); + flush_tlb_all(); + + preempt_disable(); + trace_hardirqs_off(); + + /* + * Let the primary processor know we're out of the + * pen, then head off into the C entry point + */ + write_pen_release(-1); + + /* + * Synchronise with the boot thread. + */ + raw_spin_lock(&boot_lock); + raw_spin_unlock(&boot_lock); + + /* + * Enable local interrupts. + */ + notify_cpu_starting(cpu); + local_irq_enable(); + local_fiq_enable(); + + /* + * 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. + */ + set_cpu_online(cpu, true); + while (!cpu_active(cpu)) + cpu_relax(); + + /* + * OK, it's off to the idle thread for us + */ + cpu_idle(); +} + +void __init smp_cpus_done(unsigned int max_cpus) +{ + unsigned long bogosum = loops_per_jiffy * num_online_cpus(); + + pr_info("SMP: Total of %d processors activated (%lu.%02lu BogoMIPS).\n", + num_online_cpus(), bogosum / (500000/HZ), + (bogosum / (5000/HZ)) % 100); +} + +void __init smp_prepare_boot_cpu(void) +{ +} + +static void (*smp_cross_call)(const struct cpumask *, unsigned int); +static phys_addr_t cpu_release_addr[NR_CPUS]; + +/* + * Enumerate the possible CPU set from the device tree. + */ +void __init smp_init_cpus(void) +{ + const char *enable_method; + struct device_node *dn = NULL; + int cpu = 0; + + while ((dn = of_find_node_by_type(dn, "cpu"))) { + if (cpu >= NR_CPUS) + goto next; + + /* + * We currently support only the "spin-table" enable-method. + */ + enable_method = of_get_property(dn, "enable-method", NULL); + if (!enable_method || strcmp(enable_method, "spin-table")) { + pr_err("CPU %d: missing or invalid enable-method property: %s\n", + cpu, enable_method); + goto next; + } + + /* + * Determine the address from which the CPU is polling. + */ + if (of_property_read_u64(dn, "cpu-release-addr", + &cpu_release_addr[cpu])) { + pr_err("CPU %d: missing or invalid cpu-release-addr property\n", + cpu); + goto next; + } + + set_cpu_possible(cpu, true); +next: + cpu++; + } + + /* sanity check */ + if (cpu > NR_CPUS) + pr_warning("no. of cores (%d) greater than configured maximum of %d - clipping\n", + cpu, NR_CPUS); +} + +void __init smp_prepare_cpus(unsigned int max_cpus) +{ + int cpu; + void **release_addr; + unsigned int ncores = num_possible_cpus(); + + /* + * are we trying to boot more cores than exist? + */ + if (max_cpus > ncores) + max_cpus = ncores; + + /* + * Initialise the present map (which describes the set of CPUs + * actually populated at the present time) and release the + * secondaries from the bootloader. + */ + for_each_possible_cpu(cpu) { + if (max_cpus == 0) + break; + + if (!cpu_release_addr[cpu]) + continue; + + release_addr = __va(cpu_release_addr[cpu]); + release_addr[0] = (void *)__pa(secondary_holding_pen); + __flush_dcache_area(release_addr, sizeof(release_addr[0])); + + set_cpu_present(cpu, true); + max_cpus--; + } + + /* + * Send an event to wake up the secondaries. + */ + sev(); +} + + +void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int)) +{ + smp_cross_call = fn; +} + +void arch_send_call_function_ipi_mask(const struct cpumask *mask) +{ + smp_cross_call(mask, IPI_CALL_FUNC); +} + +void arch_send_call_function_single_ipi(int cpu) +{ + smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE); +} + +static const char *ipi_types[NR_IPI] = { +#define S(x,s) [x - IPI_RESCHEDULE] = s + S(IPI_RESCHEDULE, "Rescheduling interrupts"), + S(IPI_CALL_FUNC, "Function call interrupts"), + S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"), + S(IPI_CPU_STOP, "CPU stop interrupts"), +}; + +void show_ipi_list(struct seq_file *p, int prec) +{ + unsigned int cpu, i; + + for (i = 0; i < NR_IPI; i++) { + seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i + IPI_RESCHEDULE, + prec >= 4 ? " " : ""); + for_each_present_cpu(cpu) + seq_printf(p, "%10u ", + __get_irq_stat(cpu, ipi_irqs[i])); + seq_printf(p, " %s\n", ipi_types[i]); + } +} + +u64 smp_irq_stat_cpu(unsigned int cpu) +{ + u64 sum = 0; + int i; + + for (i = 0; i < NR_IPI; i++) + sum += __get_irq_stat(cpu, ipi_irqs[i]); + + return sum; +} + +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_BOOTING || + 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(); +} + +/* + * Main handler for inter-processor interrupts + */ +void handle_IPI(int ipinr, struct pt_regs *regs) +{ + unsigned int cpu = smp_processor_id(); + struct pt_regs *old_regs = set_irq_regs(regs); + + if (ipinr >= IPI_RESCHEDULE && ipinr < IPI_RESCHEDULE + NR_IPI) + __inc_irq_stat(cpu, ipi_irqs[ipinr - IPI_RESCHEDULE]); + + switch (ipinr) { + case IPI_RESCHEDULE: + scheduler_ipi(); + break; + + case IPI_CALL_FUNC: + irq_enter(); + generic_smp_call_function_interrupt(); + irq_exit(); + break; + + case IPI_CALL_FUNC_SINGLE: + irq_enter(); + generic_smp_call_function_single_interrupt(); + irq_exit(); + break; + + case IPI_CPU_STOP: + irq_enter(); + ipi_cpu_stop(cpu); + irq_exit(); + break; + + default: + pr_crit("CPU%u: Unknown IPI message 0x%x\n", cpu, ipinr); + break; + } + set_irq_regs(old_regs); +} + +void smp_send_reschedule(int cpu) +{ + smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE); +} + +void smp_send_stop(void) +{ + unsigned long timeout; + + if (num_online_cpus() > 1) { + cpumask_t mask; + + cpumask_copy(&mask, cpu_online_mask); + cpu_clear(smp_processor_id(), 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_warning("SMP: failed to stop secondary CPUs\n"); +} + +/* + * not supported here + */ +int setup_profiling_timer(unsigned int multiplier) +{ + return -EINVAL; +} |