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 for_each_cpu(cpu, in) 60 cpumask_set_cpu(cpuid_to_hartid_map(cpu), out); 61 } 62 63 bool arch_match_cpu_phys_id(int cpu, u64 phys_id) 64 { 65 return phys_id == cpuid_to_hartid_map(cpu); 66 } 67 68 /* Unsupported */ 69 int setup_profiling_timer(unsigned int multiplier) 70 { 71 return -EINVAL; 72 } 73 74 static void ipi_stop(void) 75 { 76 set_cpu_online(smp_processor_id(), false); 77 while (1) 78 wait_for_interrupt(); 79 } 80 81 void riscv_software_interrupt(void) 82 { 83 unsigned long *pending_ipis = &ipi_data[smp_processor_id()].bits; 84 unsigned long *stats = ipi_data[smp_processor_id()].stats; 85 86 /* Clear pending IPI */ 87 csr_clear(CSR_SIP, SIE_SSIE); 88 89 while (true) { 90 unsigned long ops; 91 92 /* Order bit clearing and data access. */ 93 mb(); 94 95 ops = xchg(pending_ipis, 0); 96 if (ops == 0) 97 return; 98 99 if (ops & (1 << IPI_RESCHEDULE)) { 100 stats[IPI_RESCHEDULE]++; 101 scheduler_ipi(); 102 } 103 104 if (ops & (1 << IPI_CALL_FUNC)) { 105 stats[IPI_CALL_FUNC]++; 106 generic_smp_call_function_interrupt(); 107 } 108 109 if (ops & (1 << IPI_CPU_STOP)) { 110 stats[IPI_CPU_STOP]++; 111 ipi_stop(); 112 } 113 114 BUG_ON((ops >> IPI_MAX) != 0); 115 116 /* Order data access and bit testing. */ 117 mb(); 118 } 119 } 120 121 static void 122 send_ipi_message(const struct cpumask *to_whom, enum ipi_message_type operation) 123 { 124 int cpuid, hartid; 125 struct cpumask hartid_mask; 126 127 cpumask_clear(&hartid_mask); 128 mb(); 129 for_each_cpu(cpuid, to_whom) { 130 set_bit(operation, &ipi_data[cpuid].bits); 131 hartid = cpuid_to_hartid_map(cpuid); 132 cpumask_set_cpu(hartid, &hartid_mask); 133 } 134 mb(); 135 sbi_send_ipi(cpumask_bits(&hartid_mask)); 136 } 137 138 static const char * const ipi_names[] = { 139 [IPI_RESCHEDULE] = "Rescheduling interrupts", 140 [IPI_CALL_FUNC] = "Function call interrupts", 141 [IPI_CPU_STOP] = "CPU stop interrupts", 142 }; 143 144 void show_ipi_stats(struct seq_file *p, int prec) 145 { 146 unsigned int cpu, i; 147 148 for (i = 0; i < IPI_MAX; i++) { 149 seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i, 150 prec >= 4 ? " " : ""); 151 for_each_online_cpu(cpu) 152 seq_printf(p, "%10lu ", ipi_data[cpu].stats[i]); 153 seq_printf(p, " %s\n", ipi_names[i]); 154 } 155 } 156 157 void arch_send_call_function_ipi_mask(struct cpumask *mask) 158 { 159 send_ipi_message(mask, IPI_CALL_FUNC); 160 } 161 162 void arch_send_call_function_single_ipi(int cpu) 163 { 164 send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC); 165 } 166 167 void smp_send_stop(void) 168 { 169 unsigned long timeout; 170 171 if (num_online_cpus() > 1) { 172 cpumask_t mask; 173 174 cpumask_copy(&mask, cpu_online_mask); 175 cpumask_clear_cpu(smp_processor_id(), &mask); 176 177 if (system_state <= SYSTEM_RUNNING) 178 pr_crit("SMP: stopping secondary CPUs\n"); 179 send_ipi_message(&mask, IPI_CPU_STOP); 180 } 181 182 /* Wait up to one second for other CPUs to stop */ 183 timeout = USEC_PER_SEC; 184 while (num_online_cpus() > 1 && timeout--) 185 udelay(1); 186 187 if (num_online_cpus() > 1) 188 pr_warn("SMP: failed to stop secondary CPUs %*pbl\n", 189 cpumask_pr_args(cpu_online_mask)); 190 } 191 192 void smp_send_reschedule(int cpu) 193 { 194 send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE); 195 } 196 197