diff options
Diffstat (limited to 'arch/riscv/kernel/smp.c')
-rw-r--r-- | arch/riscv/kernel/smp.c | 279 |
1 files changed, 196 insertions, 83 deletions
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c index eb878abcaaf8..45dd4035416e 100644 --- a/arch/riscv/kernel/smp.c +++ b/arch/riscv/kernel/smp.c @@ -9,26 +9,34 @@ */ #include <linux/cpu.h> +#include <linux/clockchips.h> #include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/kexec.h> +#include <linux/percpu.h> #include <linux/profile.h> #include <linux/smp.h> #include <linux/sched.h> #include <linux/seq_file.h> #include <linux/delay.h> +#include <linux/irq.h> +#include <linux/irq_work.h> -#include <asm/clint.h> -#include <asm/sbi.h> #include <asm/tlbflush.h> #include <asm/cacheflush.h> +#include <asm/cpu_ops.h> enum ipi_message_type { IPI_RESCHEDULE, IPI_CALL_FUNC, IPI_CPU_STOP, + IPI_CPU_CRASH_STOP, + IPI_IRQ_WORK, + IPI_TIMER, IPI_MAX }; -unsigned long __cpuid_to_hartid_map[NR_CPUS] = { +unsigned long __cpuid_to_hartid_map[NR_CPUS] __ro_after_init = { [0 ... NR_CPUS-1] = INVALID_HARTID }; @@ -37,13 +45,12 @@ void __init smp_setup_processor_id(void) cpuid_to_hartid_map(0) = boot_cpu_hartid; } -/* A collection of single bit ipi messages. */ -static struct { - unsigned long stats[IPI_MAX] ____cacheline_aligned; - unsigned long bits ____cacheline_aligned; -} ipi_data[NR_CPUS] __cacheline_aligned; +static DEFINE_PER_CPU_READ_MOSTLY(int, ipi_dummy_dev); +static int ipi_virq_base __ro_after_init; +static int nr_ipi __ro_after_init = IPI_MAX; +static struct irq_desc *ipi_desc[IPI_MAX] __read_mostly; -int riscv_hartid_to_cpuid(int hartid) +int riscv_hartid_to_cpuid(unsigned long hartid) { int i; @@ -51,119 +58,160 @@ int riscv_hartid_to_cpuid(int hartid) if (cpuid_to_hartid_map(i) == hartid) return i; - pr_err("Couldn't find cpu id for hartid [%d]\n", hartid); - return i; + return -ENOENT; } -void riscv_cpuid_to_hartid_mask(const struct cpumask *in, struct cpumask *out) +static void ipi_stop(void) { - int cpu; - - cpumask_clear(out); - for_each_cpu(cpu, in) - cpumask_set_cpu(cpuid_to_hartid_map(cpu), out); + set_cpu_online(smp_processor_id(), false); + while (1) + wait_for_interrupt(); } -bool arch_match_cpu_phys_id(int cpu, u64 phys_id) +#ifdef CONFIG_KEXEC_CORE +static atomic_t waiting_for_crash_ipi = ATOMIC_INIT(0); + +static inline void ipi_cpu_crash_stop(unsigned int cpu, struct pt_regs *regs) { - return phys_id == cpuid_to_hartid_map(cpu); + crash_save_cpu(regs, cpu); + + atomic_dec(&waiting_for_crash_ipi); + + local_irq_disable(); + +#ifdef CONFIG_HOTPLUG_CPU + if (cpu_has_hotplug(cpu)) + cpu_ops->cpu_stop(); +#endif + + for(;;) + wait_for_interrupt(); +} +#else +static inline void ipi_cpu_crash_stop(unsigned int cpu, struct pt_regs *regs) +{ + unreachable(); } +#endif -/* Unsupported */ -int setup_profiling_timer(unsigned int multiplier) +static void send_ipi_mask(const struct cpumask *mask, enum ipi_message_type op) { - return -EINVAL; + __ipi_send_mask(ipi_desc[op], mask); } -static void ipi_stop(void) +static void send_ipi_single(int cpu, enum ipi_message_type op) { - set_cpu_online(smp_processor_id(), false); - while (1) - wait_for_interrupt(); + __ipi_send_mask(ipi_desc[op], cpumask_of(cpu)); } -static void send_ipi_mask(const struct cpumask *mask, enum ipi_message_type op) +#ifdef CONFIG_IRQ_WORK +void arch_irq_work_raise(void) { - struct cpumask hartid_mask; - int cpu; + send_ipi_single(smp_processor_id(), IPI_IRQ_WORK); +} +#endif - smp_mb__before_atomic(); - for_each_cpu(cpu, mask) - set_bit(op, &ipi_data[cpu].bits); - smp_mb__after_atomic(); +static irqreturn_t handle_IPI(int irq, void *data) +{ + int ipi = irq - ipi_virq_base; + + switch (ipi) { + case IPI_RESCHEDULE: + scheduler_ipi(); + break; + case IPI_CALL_FUNC: + generic_smp_call_function_interrupt(); + break; + case IPI_CPU_STOP: + ipi_stop(); + break; + case IPI_CPU_CRASH_STOP: + ipi_cpu_crash_stop(smp_processor_id(), get_irq_regs()); + break; + case IPI_IRQ_WORK: + irq_work_run(); + break; +#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST + case IPI_TIMER: + tick_receive_broadcast(); + break; +#endif + default: + pr_warn("CPU%d: unhandled IPI%d\n", smp_processor_id(), ipi); + break; + } - riscv_cpuid_to_hartid_mask(mask, &hartid_mask); - if (IS_ENABLED(CONFIG_RISCV_SBI)) - sbi_send_ipi(cpumask_bits(&hartid_mask)); - else - clint_send_ipi_mask(&hartid_mask); + return IRQ_HANDLED; } -static void send_ipi_single(int cpu, enum ipi_message_type op) +void riscv_ipi_enable(void) { - int hartid = cpuid_to_hartid_map(cpu); + int i; - smp_mb__before_atomic(); - set_bit(op, &ipi_data[cpu].bits); - smp_mb__after_atomic(); + if (WARN_ON_ONCE(!ipi_virq_base)) + return; - if (IS_ENABLED(CONFIG_RISCV_SBI)) - sbi_send_ipi(cpumask_bits(cpumask_of(hartid))); - else - clint_send_ipi_single(hartid); + for (i = 0; i < nr_ipi; i++) + enable_percpu_irq(ipi_virq_base + i, 0); } -static inline void clear_ipi(void) +void riscv_ipi_disable(void) { - if (IS_ENABLED(CONFIG_RISCV_SBI)) - csr_clear(CSR_IP, IE_SIE); - else - clint_clear_ipi(cpuid_to_hartid_map(smp_processor_id())); + int i; + + if (WARN_ON_ONCE(!ipi_virq_base)) + return; + + for (i = 0; i < nr_ipi; i++) + disable_percpu_irq(ipi_virq_base + i); } -void riscv_software_interrupt(void) +bool riscv_ipi_have_virq_range(void) { - unsigned long *pending_ipis = &ipi_data[smp_processor_id()].bits; - unsigned long *stats = ipi_data[smp_processor_id()].stats; - - clear_ipi(); + return (ipi_virq_base) ? true : false; +} - while (true) { - unsigned long ops; +DEFINE_STATIC_KEY_FALSE(riscv_ipi_for_rfence); +EXPORT_SYMBOL_GPL(riscv_ipi_for_rfence); - /* Order bit clearing and data access. */ - mb(); +void riscv_ipi_set_virq_range(int virq, int nr, bool use_for_rfence) +{ + int i, err; - ops = xchg(pending_ipis, 0); - if (ops == 0) - return; + if (WARN_ON(ipi_virq_base)) + return; - if (ops & (1 << IPI_RESCHEDULE)) { - stats[IPI_RESCHEDULE]++; - scheduler_ipi(); - } + WARN_ON(nr < IPI_MAX); + nr_ipi = min(nr, IPI_MAX); + ipi_virq_base = virq; - if (ops & (1 << IPI_CALL_FUNC)) { - stats[IPI_CALL_FUNC]++; - generic_smp_call_function_interrupt(); - } + /* Request IPIs */ + for (i = 0; i < nr_ipi; i++) { + err = request_percpu_irq(ipi_virq_base + i, handle_IPI, + "IPI", &ipi_dummy_dev); + WARN_ON(err); - if (ops & (1 << IPI_CPU_STOP)) { - stats[IPI_CPU_STOP]++; - ipi_stop(); - } + ipi_desc[i] = irq_to_desc(ipi_virq_base + i); + irq_set_status_flags(ipi_virq_base + i, IRQ_HIDDEN); + } - BUG_ON((ops >> IPI_MAX) != 0); + /* Enabled IPIs for boot CPU immediately */ + riscv_ipi_enable(); - /* Order data access and bit testing. */ - mb(); - } + /* Update RFENCE static key */ + if (use_for_rfence) + static_branch_enable(&riscv_ipi_for_rfence); + else + static_branch_disable(&riscv_ipi_for_rfence); } static const char * const ipi_names[] = { [IPI_RESCHEDULE] = "Rescheduling interrupts", [IPI_CALL_FUNC] = "Function call interrupts", [IPI_CPU_STOP] = "CPU stop interrupts", + [IPI_CPU_CRASH_STOP] = "CPU stop (for crash dump) interrupts", + [IPI_IRQ_WORK] = "IRQ work interrupts", + [IPI_TIMER] = "Timer broadcast interrupts", }; void show_ipi_stats(struct seq_file *p, int prec) @@ -174,7 +222,7 @@ void show_ipi_stats(struct seq_file *p, int prec) seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i, prec >= 4 ? " " : ""); for_each_online_cpu(cpu) - seq_printf(p, "%10lu ", ipi_data[cpu].stats[i]); + seq_printf(p, "%10u ", irq_desc_kstat_cpu(ipi_desc[i], cpu)); seq_printf(p, " %s\n", ipi_names[i]); } } @@ -189,6 +237,13 @@ void arch_send_call_function_single_ipi(int cpu) send_ipi_single(cpu, IPI_CALL_FUNC); } +#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST +void tick_broadcast(const struct cpumask *mask) +{ + send_ipi_mask(mask, IPI_TIMER); +} +#endif + void smp_send_stop(void) { unsigned long timeout; @@ -214,8 +269,66 @@ void smp_send_stop(void) cpumask_pr_args(cpu_online_mask)); } -void smp_send_reschedule(int cpu) +#ifdef CONFIG_KEXEC_CORE +/* + * The number of CPUs online, not counting this CPU (which may not be + * fully online and so not counted in num_online_cpus()). + */ +static inline unsigned int num_other_online_cpus(void) +{ + unsigned int this_cpu_online = cpu_online(smp_processor_id()); + + return num_online_cpus() - this_cpu_online; +} + +void crash_smp_send_stop(void) +{ + static int cpus_stopped; + cpumask_t mask; + unsigned long timeout; + + /* + * This function can be called twice in panic path, but obviously + * we execute this only once. + */ + if (cpus_stopped) + return; + + cpus_stopped = 1; + + /* + * If this cpu is the only one alive at this point in time, online or + * not, there are no stop messages to be sent around, so just back out. + */ + if (num_other_online_cpus() == 0) + return; + + cpumask_copy(&mask, cpu_online_mask); + cpumask_clear_cpu(smp_processor_id(), &mask); + + atomic_set(&waiting_for_crash_ipi, num_other_online_cpus()); + + pr_crit("SMP: stopping secondary CPUs\n"); + send_ipi_mask(&mask, IPI_CPU_CRASH_STOP); + + /* Wait up to one second for other CPUs to stop */ + timeout = USEC_PER_SEC; + while ((atomic_read(&waiting_for_crash_ipi) > 0) && timeout--) + udelay(1); + + if (atomic_read(&waiting_for_crash_ipi) > 0) + pr_warn("SMP: failed to stop secondary CPUs %*pbl\n", + cpumask_pr_args(&mask)); +} + +bool smp_crash_stop_failed(void) +{ + return (atomic_read(&waiting_for_crash_ipi) > 0); +} +#endif + +void arch_smp_send_reschedule(int cpu) { send_ipi_single(cpu, IPI_RESCHEDULE); } -EXPORT_SYMBOL_GPL(smp_send_reschedule); +EXPORT_SYMBOL_GPL(arch_smp_send_reschedule); |