1 // SPDX-License-Identifier: GPL-2.0-only
3 * SMP initialisation and IPI support
4 * Based on arch/arm64/kernel/smp.c
6 * Copyright (C) 2012 ARM Ltd.
7 * Copyright (C) 2015 Regents of the University of California
8 * Copyright (C) 2017 SiFive
11 #include <linux/cpu.h>
12 #include <linux/interrupt.h>
13 #include <linux/module.h>
14 #include <linux/profile.h>
15 #include <linux/smp.h>
16 #include <linux/sched.h>
17 #include <linux/seq_file.h>
18 #include <linux/delay.h>
19 #include <linux/irq_work.h>
22 #include <asm/tlbflush.h>
23 #include <asm/cacheflush.h>
25 enum ipi_message_type {
33 unsigned long __cpuid_to_hartid_map[NR_CPUS] = {
34 [0 ... NR_CPUS-1] = INVALID_HARTID
37 void __init smp_setup_processor_id(void)
39 cpuid_to_hartid_map(0) = boot_cpu_hartid;
42 /* A collection of single bit ipi messages. */
44 unsigned long stats[IPI_MAX] ____cacheline_aligned;
45 unsigned long bits ____cacheline_aligned;
46 } ipi_data[NR_CPUS] __cacheline_aligned;
48 int riscv_hartid_to_cpuid(int hartid)
52 for (i = 0; i < NR_CPUS; i++)
53 if (cpuid_to_hartid_map(i) == hartid)
56 pr_err("Couldn't find cpu id for hartid [%d]\n", hartid);
60 void riscv_cpuid_to_hartid_mask(const struct cpumask *in, struct cpumask *out)
66 cpumask_set_cpu(cpuid_to_hartid_map(cpu), out);
68 EXPORT_SYMBOL_GPL(riscv_cpuid_to_hartid_mask);
70 bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
72 return phys_id == cpuid_to_hartid_map(cpu);
76 int setup_profiling_timer(unsigned int multiplier)
81 static void ipi_stop(void)
83 set_cpu_online(smp_processor_id(), false);
88 static struct riscv_ipi_ops *ipi_ops;
90 void riscv_set_ipi_ops(struct riscv_ipi_ops *ops)
94 EXPORT_SYMBOL_GPL(riscv_set_ipi_ops);
96 void riscv_clear_ipi(void)
98 if (ipi_ops && ipi_ops->ipi_clear)
101 csr_clear(CSR_IP, IE_SIE);
103 EXPORT_SYMBOL_GPL(riscv_clear_ipi);
105 static void send_ipi_mask(const struct cpumask *mask, enum ipi_message_type op)
109 smp_mb__before_atomic();
110 for_each_cpu(cpu, mask)
111 set_bit(op, &ipi_data[cpu].bits);
112 smp_mb__after_atomic();
114 if (ipi_ops && ipi_ops->ipi_inject)
115 ipi_ops->ipi_inject(mask);
117 pr_warn("SMP: IPI inject method not available\n");
120 static void send_ipi_single(int cpu, enum ipi_message_type op)
122 smp_mb__before_atomic();
123 set_bit(op, &ipi_data[cpu].bits);
124 smp_mb__after_atomic();
126 if (ipi_ops && ipi_ops->ipi_inject)
127 ipi_ops->ipi_inject(cpumask_of(cpu));
129 pr_warn("SMP: IPI inject method not available\n");
132 #ifdef CONFIG_IRQ_WORK
133 void arch_irq_work_raise(void)
135 send_ipi_single(smp_processor_id(), IPI_IRQ_WORK);
139 void handle_IPI(struct pt_regs *regs)
141 struct pt_regs *old_regs = set_irq_regs(regs);
142 unsigned long *pending_ipis = &ipi_data[smp_processor_id()].bits;
143 unsigned long *stats = ipi_data[smp_processor_id()].stats;
152 /* Order bit clearing and data access. */
155 ops = xchg(pending_ipis, 0);
159 if (ops & (1 << IPI_RESCHEDULE)) {
160 stats[IPI_RESCHEDULE]++;
164 if (ops & (1 << IPI_CALL_FUNC)) {
165 stats[IPI_CALL_FUNC]++;
166 generic_smp_call_function_interrupt();
169 if (ops & (1 << IPI_CPU_STOP)) {
170 stats[IPI_CPU_STOP]++;
174 if (ops & (1 << IPI_IRQ_WORK)) {
175 stats[IPI_IRQ_WORK]++;
179 BUG_ON((ops >> IPI_MAX) != 0);
181 /* Order data access and bit testing. */
187 set_irq_regs(old_regs);
190 static const char * const ipi_names[] = {
191 [IPI_RESCHEDULE] = "Rescheduling interrupts",
192 [IPI_CALL_FUNC] = "Function call interrupts",
193 [IPI_CPU_STOP] = "CPU stop interrupts",
194 [IPI_IRQ_WORK] = "IRQ work interrupts",
197 void show_ipi_stats(struct seq_file *p, int prec)
201 for (i = 0; i < IPI_MAX; i++) {
202 seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i,
203 prec >= 4 ? " " : "");
204 for_each_online_cpu(cpu)
205 seq_printf(p, "%10lu ", ipi_data[cpu].stats[i]);
206 seq_printf(p, " %s\n", ipi_names[i]);
210 void arch_send_call_function_ipi_mask(struct cpumask *mask)
212 send_ipi_mask(mask, IPI_CALL_FUNC);
215 void arch_send_call_function_single_ipi(int cpu)
217 send_ipi_single(cpu, IPI_CALL_FUNC);
220 void smp_send_stop(void)
222 unsigned long timeout;
224 if (num_online_cpus() > 1) {
227 cpumask_copy(&mask, cpu_online_mask);
228 cpumask_clear_cpu(smp_processor_id(), &mask);
230 if (system_state <= SYSTEM_RUNNING)
231 pr_crit("SMP: stopping secondary CPUs\n");
232 send_ipi_mask(&mask, IPI_CPU_STOP);
235 /* Wait up to one second for other CPUs to stop */
236 timeout = USEC_PER_SEC;
237 while (num_online_cpus() > 1 && timeout--)
240 if (num_online_cpus() > 1)
241 pr_warn("SMP: failed to stop secondary CPUs %*pbl\n",
242 cpumask_pr_args(cpu_online_mask));
245 void smp_send_reschedule(int cpu)
247 send_ipi_single(cpu, IPI_RESCHEDULE);
249 EXPORT_SYMBOL_GPL(smp_send_reschedule);