| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) |
| * |
| * RajeshwarR: Dec 11, 2007 |
| * -- Added support for Inter Processor Interrupts |
| * |
| * Vineetg: Nov 1st, 2007 |
| * -- Initial Write (Borrowed heavily from ARM) |
| */ |
| |
| #include <linux/spinlock.h> |
| #include <linux/sched/mm.h> |
| #include <linux/interrupt.h> |
| #include <linux/profile.h> |
| #include <linux/mm.h> |
| #include <linux/cpu.h> |
| #include <linux/irq.h> |
| #include <linux/atomic.h> |
| #include <linux/cpumask.h> |
| #include <linux/reboot.h> |
| #include <linux/irqdomain.h> |
| #include <linux/export.h> |
| #include <linux/of_fdt.h> |
| |
| #include <asm/processor.h> |
| #include <asm/setup.h> |
| #include <asm/mach_desc.h> |
| |
| #ifndef CONFIG_ARC_HAS_LLSC |
| arch_spinlock_t smp_atomic_ops_lock = __ARCH_SPIN_LOCK_UNLOCKED; |
| |
| EXPORT_SYMBOL_GPL(smp_atomic_ops_lock); |
| #endif |
| |
| struct plat_smp_ops __weak plat_smp_ops; |
| |
| /* XXX: per cpu ? Only needed once in early secondary boot */ |
| struct task_struct *secondary_idle_tsk; |
| |
| /* Called from start_kernel */ |
| void __init smp_prepare_boot_cpu(void) |
| { |
| } |
| |
| static int __init arc_get_cpu_map(const char *name, struct cpumask *cpumask) |
| { |
| unsigned long dt_root = of_get_flat_dt_root(); |
| const char *buf; |
| |
| buf = of_get_flat_dt_prop(dt_root, name, NULL); |
| if (!buf) |
| return -EINVAL; |
| |
| if (cpulist_parse(buf, cpumask)) |
| return -EINVAL; |
| |
| return 0; |
| } |
| |
| /* |
| * Read from DeviceTree and setup cpu possible mask. If there is no |
| * "possible-cpus" property in DeviceTree pretend all [0..NR_CPUS-1] exist. |
| */ |
| static void __init arc_init_cpu_possible(void) |
| { |
| struct cpumask cpumask; |
| |
| if (arc_get_cpu_map("possible-cpus", &cpumask)) { |
| pr_warn("Failed to get possible-cpus from dtb, pretending all %u cpus exist\n", |
| NR_CPUS); |
| |
| cpumask_setall(&cpumask); |
| } |
| |
| if (!cpumask_test_cpu(0, &cpumask)) |
| panic("Master cpu (cpu[0]) is missed in cpu possible mask!"); |
| |
| init_cpu_possible(&cpumask); |
| } |
| |
| /* |
| * Called from setup_arch() before calling setup_processor() |
| * |
| * - Initialise the CPU possible map early - this describes the CPUs |
| * which may be present or become present in the system. |
| * - Call early smp init hook. This can initialize a specific multi-core |
| * IP which is say common to several platforms (hence not part of |
| * platform specific int_early() hook) |
| */ |
| void __init smp_init_cpus(void) |
| { |
| arc_init_cpu_possible(); |
| |
| if (plat_smp_ops.init_early_smp) |
| plat_smp_ops.init_early_smp(); |
| } |
| |
| /* called from init ( ) => process 1 */ |
| void __init smp_prepare_cpus(unsigned int max_cpus) |
| { |
| /* |
| * if platform didn't set the present map already, do it now |
| * boot cpu is set to present already by init/main.c |
| */ |
| if (num_present_cpus() <= 1) |
| init_cpu_present(cpu_possible_mask); |
| } |
| |
| void __init smp_cpus_done(unsigned int max_cpus) |
| { |
| |
| } |
| |
| /* |
| * Default smp boot helper for Run-on-reset case where all cores start off |
| * together. Non-masters need to wait for Master to start running. |
| * This is implemented using a flag in memory, which Non-masters spin-wait on. |
| * Master sets it to cpu-id of core to "ungate" it. |
| */ |
| static volatile int wake_flag; |
| |
| #ifdef CONFIG_ISA_ARCOMPACT |
| |
| #define __boot_read(f) f |
| #define __boot_write(f, v) f = v |
| |
| #else |
| |
| #define __boot_read(f) arc_read_uncached_32(&f) |
| #define __boot_write(f, v) arc_write_uncached_32(&f, v) |
| |
| #endif |
| |
| static void arc_default_smp_cpu_kick(int cpu, unsigned long pc) |
| { |
| BUG_ON(cpu == 0); |
| |
| __boot_write(wake_flag, cpu); |
| } |
| |
| void arc_platform_smp_wait_to_boot(int cpu) |
| { |
| /* for halt-on-reset, we've waited already */ |
| if (IS_ENABLED(CONFIG_ARC_SMP_HALT_ON_RESET)) |
| return; |
| |
| while (__boot_read(wake_flag) != cpu) |
| ; |
| |
| __boot_write(wake_flag, 0); |
| } |
| |
| const char *arc_platform_smp_cpuinfo(void) |
| { |
| return plat_smp_ops.info ? : ""; |
| } |
| |
| /* |
| * The very first "C" code executed by secondary |
| * Called from asm stub in head.S |
| * "current"/R25 already setup by low level boot code |
| */ |
| void start_kernel_secondary(void) |
| { |
| struct mm_struct *mm = &init_mm; |
| unsigned int cpu = smp_processor_id(); |
| |
| /* MMU, Caches, Vector Table, Interrupts etc */ |
| setup_processor(); |
| |
| mmget(mm); |
| mmgrab(mm); |
| current->active_mm = mm; |
| cpumask_set_cpu(cpu, mm_cpumask(mm)); |
| |
| /* Some SMP H/w setup - for each cpu */ |
| if (plat_smp_ops.init_per_cpu) |
| plat_smp_ops.init_per_cpu(cpu); |
| |
| if (machine_desc->init_per_cpu) |
| machine_desc->init_per_cpu(cpu); |
| |
| notify_cpu_starting(cpu); |
| set_cpu_online(cpu, true); |
| |
| pr_info("## CPU%u LIVE ##: Executing Code...\n", cpu); |
| |
| local_irq_enable(); |
| cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); |
| } |
| |
| /* |
| * Called from kernel_init( ) -> smp_init( ) - for each CPU |
| * |
| * At this point, Secondary Processor is "HALT"ed: |
| * -It booted, but was halted in head.S |
| * -It was configured to halt-on-reset |
| * So need to wake it up. |
| * |
| * Essential requirements being where to run from (PC) and stack (SP) |
| */ |
| int __cpu_up(unsigned int cpu, struct task_struct *idle) |
| { |
| unsigned long wait_till; |
| |
| secondary_idle_tsk = idle; |
| |
| pr_info("Idle Task [%d] %p", cpu, idle); |
| pr_info("Trying to bring up CPU%u ...\n", cpu); |
| |
| if (plat_smp_ops.cpu_kick) |
| plat_smp_ops.cpu_kick(cpu, |
| (unsigned long)first_lines_of_secondary); |
| else |
| arc_default_smp_cpu_kick(cpu, (unsigned long)NULL); |
| |
| /* wait for 1 sec after kicking the secondary */ |
| wait_till = jiffies + HZ; |
| while (time_before(jiffies, wait_till)) { |
| if (cpu_online(cpu)) |
| break; |
| } |
| |
| if (!cpu_online(cpu)) { |
| pr_info("Timeout: CPU%u FAILED to come up !!!\n", cpu); |
| return -1; |
| } |
| |
| secondary_idle_tsk = NULL; |
| |
| return 0; |
| } |
| |
| /*****************************************************************************/ |
| /* Inter Processor Interrupt Handling */ |
| /*****************************************************************************/ |
| |
| enum ipi_msg_type { |
| IPI_EMPTY = 0, |
| IPI_RESCHEDULE = 1, |
| IPI_CALL_FUNC, |
| IPI_CPU_STOP, |
| }; |
| |
| /* |
| * In arches with IRQ for each msg type (above), receiver can use IRQ-id to |
| * figure out what msg was sent. For those which don't (ARC has dedicated IPI |
| * IRQ), the msg-type needs to be conveyed via per-cpu data |
| */ |
| |
| static DEFINE_PER_CPU(unsigned long, ipi_data); |
| |
| static void ipi_send_msg_one(int cpu, enum ipi_msg_type msg) |
| { |
| unsigned long __percpu *ipi_data_ptr = per_cpu_ptr(&ipi_data, cpu); |
| unsigned long old, new; |
| unsigned long flags; |
| |
| pr_debug("%d Sending msg [%d] to %d\n", smp_processor_id(), msg, cpu); |
| |
| local_irq_save(flags); |
| |
| /* |
| * Atomically write new msg bit (in case others are writing too), |
| * and read back old value |
| */ |
| do { |
| new = old = *ipi_data_ptr; |
| new |= 1U << msg; |
| } while (cmpxchg(ipi_data_ptr, old, new) != old); |
| |
| /* |
| * Call the platform specific IPI kick function, but avoid if possible: |
| * Only do so if there's no pending msg from other concurrent sender(s). |
| * Otherwise, receiver will see this msg as well when it takes the |
| * IPI corresponding to that msg. This is true, even if it is already in |
| * IPI handler, because !@old means it has not yet dequeued the msg(s) |
| * so @new msg can be a free-loader |
| */ |
| if (plat_smp_ops.ipi_send && !old) |
| plat_smp_ops.ipi_send(cpu); |
| |
| local_irq_restore(flags); |
| } |
| |
| static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg) |
| { |
| unsigned int cpu; |
| |
| for_each_cpu(cpu, callmap) |
| ipi_send_msg_one(cpu, msg); |
| } |
| |
| void smp_send_reschedule(int cpu) |
| { |
| ipi_send_msg_one(cpu, IPI_RESCHEDULE); |
| } |
| |
| void smp_send_stop(void) |
| { |
| struct cpumask targets; |
| cpumask_copy(&targets, cpu_online_mask); |
| cpumask_clear_cpu(smp_processor_id(), &targets); |
| ipi_send_msg(&targets, IPI_CPU_STOP); |
| } |
| |
| void arch_send_call_function_single_ipi(int cpu) |
| { |
| ipi_send_msg_one(cpu, IPI_CALL_FUNC); |
| } |
| |
| void arch_send_call_function_ipi_mask(const struct cpumask *mask) |
| { |
| ipi_send_msg(mask, IPI_CALL_FUNC); |
| } |
| |
| /* |
| * ipi_cpu_stop - handle IPI from smp_send_stop() |
| */ |
| static void ipi_cpu_stop(void) |
| { |
| machine_halt(); |
| } |
| |
| static inline int __do_IPI(unsigned long msg) |
| { |
| int rc = 0; |
| |
| switch (msg) { |
| case IPI_RESCHEDULE: |
| scheduler_ipi(); |
| break; |
| |
| case IPI_CALL_FUNC: |
| generic_smp_call_function_interrupt(); |
| break; |
| |
| case IPI_CPU_STOP: |
| ipi_cpu_stop(); |
| break; |
| |
| default: |
| rc = 1; |
| } |
| |
| return rc; |
| } |
| |
| /* |
| * arch-common ISR to handle for inter-processor interrupts |
| * Has hooks for platform specific IPI |
| */ |
| irqreturn_t do_IPI(int irq, void *dev_id) |
| { |
| unsigned long pending; |
| unsigned long __maybe_unused copy; |
| |
| pr_debug("IPI [%ld] received on cpu %d\n", |
| *this_cpu_ptr(&ipi_data), smp_processor_id()); |
| |
| if (plat_smp_ops.ipi_clear) |
| plat_smp_ops.ipi_clear(irq); |
| |
| /* |
| * "dequeue" the msg corresponding to this IPI (and possibly other |
| * piggybacked msg from elided IPIs: see ipi_send_msg_one() above) |
| */ |
| copy = pending = xchg(this_cpu_ptr(&ipi_data), 0); |
| |
| do { |
| unsigned long msg = __ffs(pending); |
| int rc; |
| |
| rc = __do_IPI(msg); |
| if (rc) |
| pr_info("IPI with bogus msg %ld in %ld\n", msg, copy); |
| pending &= ~(1U << msg); |
| } while (pending); |
| |
| return IRQ_HANDLED; |
| } |
| |
| /* |
| * API called by platform code to hookup arch-common ISR to their IPI IRQ |
| * |
| * Note: If IPI is provided by platform (vs. say ARC MCIP), their intc setup/map |
| * function needs to call irq_set_percpu_devid() for IPI IRQ, otherwise |
| * request_percpu_irq() below will fail |
| */ |
| static DEFINE_PER_CPU(int, ipi_dev); |
| |
| int smp_ipi_irq_setup(int cpu, irq_hw_number_t hwirq) |
| { |
| int *dev = per_cpu_ptr(&ipi_dev, cpu); |
| unsigned int virq = irq_find_mapping(NULL, hwirq); |
| |
| if (!virq) |
| panic("Cannot find virq for root domain and hwirq=%lu", hwirq); |
| |
| /* Boot cpu calls request, all call enable */ |
| if (!cpu) { |
| int rc; |
| |
| rc = request_percpu_irq(virq, do_IPI, "IPI Interrupt", dev); |
| if (rc) |
| panic("Percpu IRQ request failed for %u\n", virq); |
| } |
| |
| enable_percpu_irq(virq, 0); |
| |
| return 0; |
| } |