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/interrupt.h> 12 #include <linux/smp.h> 13 #include <linux/sched.h> 14 #include <linux/seq_file.h> 15 #include <linux/delay.h> 16 17 #include <asm/sbi.h> 18 #include <asm/tlbflush.h> 19 #include <asm/cacheflush.h> 20 21 enum ipi_message_type { 22 IPI_RESCHEDULE, 23 IPI_CALL_FUNC, 24 IPI_CPU_STOP, 25 IPI_MAX 26 }; 27 28 unsigned long __cpuid_to_hartid_map[NR_CPUS] = { 29 [0 ... NR_CPUS-1] = INVALID_HARTID 30 }; 31 32 void __init smp_setup_processor_id(void) 33 { 34 cpuid_to_hartid_map(0) = boot_cpu_hartid; 35 } 36 37 /* A collection of single bit ipi messages. */ 38 static struct { 39 unsigned long stats[IPI_MAX] ____cacheline_aligned; 40 unsigned long bits ____cacheline_aligned; 41 } ipi_data[NR_CPUS] __cacheline_aligned; 42 43 int riscv_hartid_to_cpuid(int hartid) 44 { 45 int i; 46 47 for (i = 0; i < NR_CPUS; i++) 48 if (cpuid_to_hartid_map(i) == hartid) 49 return i; 50 51 pr_err("Couldn't find cpu id for hartid [%d]\n", hartid); 52 return i; 53 } 54 55 void riscv_cpuid_to_hartid_mask(const struct cpumask *in, struct cpumask *out) 56 { 57 int cpu; 58 59 cpumask_clear(out); 60 for_each_cpu(cpu, in) 61 cpumask_set_cpu(cpuid_to_hartid_map(cpu), out); 62 } 63 64 bool arch_match_cpu_phys_id(int cpu, u64 phys_id) 65 { 66 return phys_id == cpuid_to_hartid_map(cpu); 67 } 68 69 /* Unsupported */ 70 int setup_profiling_timer(unsigned int multiplier) 71 { 72 return -EINVAL; 73 } 74 75 static void ipi_stop(void) 76 { 77 set_cpu_online(smp_processor_id(), false); 78 while (1) 79 wait_for_interrupt(); 80 } 81 82 static void send_ipi_mask(const struct cpumask *mask, enum ipi_message_type op) 83 { 84 struct cpumask hartid_mask; 85 int cpu; 86 87 smp_mb__before_atomic(); 88 for_each_cpu(cpu, mask) 89 set_bit(op, &ipi_data[cpu].bits); 90 smp_mb__after_atomic(); 91 92 riscv_cpuid_to_hartid_mask(mask, &hartid_mask); 93 sbi_send_ipi(cpumask_bits(&hartid_mask)); 94 } 95 96 static void send_ipi_single(int cpu, enum ipi_message_type op) 97 { 98 int hartid = cpuid_to_hartid_map(cpu); 99 100 smp_mb__before_atomic(); 101 set_bit(op, &ipi_data[cpu].bits); 102 smp_mb__after_atomic(); 103 104 sbi_send_ipi(cpumask_bits(cpumask_of(hartid))); 105 } 106 107 static inline void clear_ipi(void) 108 { 109 csr_clear(CSR_SIP, SIE_SSIE); 110 } 111 112 void riscv_software_interrupt(void) 113 { 114 unsigned long *pending_ipis = &ipi_data[smp_processor_id()].bits; 115 unsigned long *stats = ipi_data[smp_processor_id()].stats; 116 117 clear_ipi(); 118 119 while (true) { 120 unsigned long ops; 121 122 /* Order bit clearing and data access. */ 123 mb(); 124 125 ops = xchg(pending_ipis, 0); 126 if (ops == 0) 127 return; 128 129 if (ops & (1 << IPI_RESCHEDULE)) { 130 stats[IPI_RESCHEDULE]++; 131 scheduler_ipi(); 132 } 133 134 if (ops & (1 << IPI_CALL_FUNC)) { 135 stats[IPI_CALL_FUNC]++; 136 generic_smp_call_function_interrupt(); 137 } 138 139 if (ops & (1 << IPI_CPU_STOP)) { 140 stats[IPI_CPU_STOP]++; 141 ipi_stop(); 142 } 143 144 BUG_ON((ops >> IPI_MAX) != 0); 145 146 /* Order data access and bit testing. */ 147 mb(); 148 } 149 } 150 151 static const char * const ipi_names[] = { 152 [IPI_RESCHEDULE] = "Rescheduling interrupts", 153 [IPI_CALL_FUNC] = "Function call interrupts", 154 [IPI_CPU_STOP] = "CPU stop interrupts", 155 }; 156 157 void show_ipi_stats(struct seq_file *p, int prec) 158 { 159 unsigned int cpu, i; 160 161 for (i = 0; i < IPI_MAX; i++) { 162 seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i, 163 prec >= 4 ? " " : ""); 164 for_each_online_cpu(cpu) 165 seq_printf(p, "%10lu ", ipi_data[cpu].stats[i]); 166 seq_printf(p, " %s\n", ipi_names[i]); 167 } 168 } 169 170 void arch_send_call_function_ipi_mask(struct cpumask *mask) 171 { 172 send_ipi_mask(mask, IPI_CALL_FUNC); 173 } 174 175 void arch_send_call_function_single_ipi(int cpu) 176 { 177 send_ipi_single(cpu, IPI_CALL_FUNC); 178 } 179 180 void smp_send_stop(void) 181 { 182 unsigned long timeout; 183 184 if (num_online_cpus() > 1) { 185 cpumask_t mask; 186 187 cpumask_copy(&mask, cpu_online_mask); 188 cpumask_clear_cpu(smp_processor_id(), &mask); 189 190 if (system_state <= SYSTEM_RUNNING) 191 pr_crit("SMP: stopping secondary CPUs\n"); 192 send_ipi_mask(&mask, IPI_CPU_STOP); 193 } 194 195 /* Wait up to one second for other CPUs to stop */ 196 timeout = USEC_PER_SEC; 197 while (num_online_cpus() > 1 && timeout--) 198 udelay(1); 199 200 if (num_online_cpus() > 1) 201 pr_warn("SMP: failed to stop secondary CPUs %*pbl\n", 202 cpumask_pr_args(cpu_online_mask)); 203 } 204 205 void smp_send_reschedule(int cpu) 206 { 207 send_ipi_single(cpu, IPI_RESCHEDULE); 208 } 209 EXPORT_SYMBOL_GPL(smp_send_reschedule); 210