1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * SMP initialisation and IPI support 4 * Based on arch/arm64/kernel/smp.c 5 * 6 * Copyright (C) 2012 ARM Ltd. 7 * Copyright (C) 2015 Regents of the University of California 8 * Copyright (C) 2017 SiFive 9 */ 10 11 #include <linux/cpu.h> 12 #include <linux/clockchips.h> 13 #include <linux/interrupt.h> 14 #include <linux/module.h> 15 #include <linux/profile.h> 16 #include <linux/smp.h> 17 #include <linux/sched.h> 18 #include <linux/seq_file.h> 19 #include <linux/delay.h> 20 #include <linux/irq_work.h> 21 22 #include <asm/sbi.h> 23 #include <asm/tlbflush.h> 24 #include <asm/cacheflush.h> 25 26 enum ipi_message_type { 27 IPI_RESCHEDULE, 28 IPI_CALL_FUNC, 29 IPI_CPU_STOP, 30 IPI_IRQ_WORK, 31 IPI_TIMER, 32 IPI_MAX 33 }; 34 35 unsigned long __cpuid_to_hartid_map[NR_CPUS] __ro_after_init = { 36 [0 ... NR_CPUS-1] = INVALID_HARTID 37 }; 38 39 void __init smp_setup_processor_id(void) 40 { 41 cpuid_to_hartid_map(0) = boot_cpu_hartid; 42 } 43 44 /* A collection of single bit ipi messages. */ 45 static struct { 46 unsigned long stats[IPI_MAX] ____cacheline_aligned; 47 unsigned long bits ____cacheline_aligned; 48 } ipi_data[NR_CPUS] __cacheline_aligned; 49 50 int riscv_hartid_to_cpuid(int hartid) 51 { 52 int i; 53 54 for (i = 0; i < NR_CPUS; i++) 55 if (cpuid_to_hartid_map(i) == hartid) 56 return i; 57 58 pr_err("Couldn't find cpu id for hartid [%d]\n", hartid); 59 return -ENOENT; 60 } 61 62 void riscv_cpuid_to_hartid_mask(const struct cpumask *in, struct cpumask *out) 63 { 64 int cpu; 65 66 cpumask_clear(out); 67 for_each_cpu(cpu, in) 68 cpumask_set_cpu(cpuid_to_hartid_map(cpu), out); 69 } 70 EXPORT_SYMBOL_GPL(riscv_cpuid_to_hartid_mask); 71 72 bool arch_match_cpu_phys_id(int cpu, u64 phys_id) 73 { 74 return phys_id == cpuid_to_hartid_map(cpu); 75 } 76 77 /* Unsupported */ 78 int setup_profiling_timer(unsigned int multiplier) 79 { 80 return -EINVAL; 81 } 82 83 static void ipi_stop(void) 84 { 85 set_cpu_online(smp_processor_id(), false); 86 while (1) 87 wait_for_interrupt(); 88 } 89 90 static const struct riscv_ipi_ops *ipi_ops __ro_after_init; 91 92 void riscv_set_ipi_ops(const struct riscv_ipi_ops *ops) 93 { 94 ipi_ops = ops; 95 } 96 EXPORT_SYMBOL_GPL(riscv_set_ipi_ops); 97 98 void riscv_clear_ipi(void) 99 { 100 if (ipi_ops && ipi_ops->ipi_clear) 101 ipi_ops->ipi_clear(); 102 103 csr_clear(CSR_IP, IE_SIE); 104 } 105 EXPORT_SYMBOL_GPL(riscv_clear_ipi); 106 107 static void send_ipi_mask(const struct cpumask *mask, enum ipi_message_type op) 108 { 109 int cpu; 110 111 smp_mb__before_atomic(); 112 for_each_cpu(cpu, mask) 113 set_bit(op, &ipi_data[cpu].bits); 114 smp_mb__after_atomic(); 115 116 if (ipi_ops && ipi_ops->ipi_inject) 117 ipi_ops->ipi_inject(mask); 118 else 119 pr_warn("SMP: IPI inject method not available\n"); 120 } 121 122 static void send_ipi_single(int cpu, enum ipi_message_type op) 123 { 124 smp_mb__before_atomic(); 125 set_bit(op, &ipi_data[cpu].bits); 126 smp_mb__after_atomic(); 127 128 if (ipi_ops && ipi_ops->ipi_inject) 129 ipi_ops->ipi_inject(cpumask_of(cpu)); 130 else 131 pr_warn("SMP: IPI inject method not available\n"); 132 } 133 134 #ifdef CONFIG_IRQ_WORK 135 void arch_irq_work_raise(void) 136 { 137 send_ipi_single(smp_processor_id(), IPI_IRQ_WORK); 138 } 139 #endif 140 141 void handle_IPI(struct pt_regs *regs) 142 { 143 struct pt_regs *old_regs = set_irq_regs(regs); 144 unsigned long *pending_ipis = &ipi_data[smp_processor_id()].bits; 145 unsigned long *stats = ipi_data[smp_processor_id()].stats; 146 147 irq_enter(); 148 149 riscv_clear_ipi(); 150 151 while (true) { 152 unsigned long ops; 153 154 /* Order bit clearing and data access. */ 155 mb(); 156 157 ops = xchg(pending_ipis, 0); 158 if (ops == 0) 159 goto done; 160 161 if (ops & (1 << IPI_RESCHEDULE)) { 162 stats[IPI_RESCHEDULE]++; 163 scheduler_ipi(); 164 } 165 166 if (ops & (1 << IPI_CALL_FUNC)) { 167 stats[IPI_CALL_FUNC]++; 168 generic_smp_call_function_interrupt(); 169 } 170 171 if (ops & (1 << IPI_CPU_STOP)) { 172 stats[IPI_CPU_STOP]++; 173 ipi_stop(); 174 } 175 176 if (ops & (1 << IPI_IRQ_WORK)) { 177 stats[IPI_IRQ_WORK]++; 178 irq_work_run(); 179 } 180 181 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST 182 if (ops & (1 << IPI_TIMER)) { 183 stats[IPI_TIMER]++; 184 tick_receive_broadcast(); 185 } 186 #endif 187 BUG_ON((ops >> IPI_MAX) != 0); 188 189 /* Order data access and bit testing. */ 190 mb(); 191 } 192 193 done: 194 irq_exit(); 195 set_irq_regs(old_regs); 196 } 197 198 static const char * const ipi_names[] = { 199 [IPI_RESCHEDULE] = "Rescheduling interrupts", 200 [IPI_CALL_FUNC] = "Function call interrupts", 201 [IPI_CPU_STOP] = "CPU stop interrupts", 202 [IPI_IRQ_WORK] = "IRQ work interrupts", 203 [IPI_TIMER] = "Timer broadcast interrupts", 204 }; 205 206 void show_ipi_stats(struct seq_file *p, int prec) 207 { 208 unsigned int cpu, i; 209 210 for (i = 0; i < IPI_MAX; i++) { 211 seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i, 212 prec >= 4 ? " " : ""); 213 for_each_online_cpu(cpu) 214 seq_printf(p, "%10lu ", ipi_data[cpu].stats[i]); 215 seq_printf(p, " %s\n", ipi_names[i]); 216 } 217 } 218 219 void arch_send_call_function_ipi_mask(struct cpumask *mask) 220 { 221 send_ipi_mask(mask, IPI_CALL_FUNC); 222 } 223 224 void arch_send_call_function_single_ipi(int cpu) 225 { 226 send_ipi_single(cpu, IPI_CALL_FUNC); 227 } 228 229 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST 230 void tick_broadcast(const struct cpumask *mask) 231 { 232 send_ipi_mask(mask, IPI_TIMER); 233 } 234 #endif 235 236 void smp_send_stop(void) 237 { 238 unsigned long timeout; 239 240 if (num_online_cpus() > 1) { 241 cpumask_t mask; 242 243 cpumask_copy(&mask, cpu_online_mask); 244 cpumask_clear_cpu(smp_processor_id(), &mask); 245 246 if (system_state <= SYSTEM_RUNNING) 247 pr_crit("SMP: stopping secondary CPUs\n"); 248 send_ipi_mask(&mask, IPI_CPU_STOP); 249 } 250 251 /* Wait up to one second for other CPUs to stop */ 252 timeout = USEC_PER_SEC; 253 while (num_online_cpus() > 1 && timeout--) 254 udelay(1); 255 256 if (num_online_cpus() > 1) 257 pr_warn("SMP: failed to stop secondary CPUs %*pbl\n", 258 cpumask_pr_args(cpu_online_mask)); 259 } 260 261 void smp_send_reschedule(int cpu) 262 { 263 send_ipi_single(cpu, IPI_RESCHEDULE); 264 } 265 EXPORT_SYMBOL_GPL(smp_send_reschedule); 266