1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __LINUX_SMP_H 3 #define __LINUX_SMP_H 4 5 /* 6 * Generic SMP support 7 * Alan Cox. <[email protected]> 8 */ 9 10 #include <linux/errno.h> 11 #include <linux/types.h> 12 #include <linux/list.h> 13 #include <linux/cpumask.h> 14 #include <linux/init.h> 15 #include <linux/smp_types.h> 16 17 typedef void (*smp_call_func_t)(void *info); 18 typedef bool (*smp_cond_func_t)(int cpu, void *info); 19 20 /* 21 * structure shares (partial) layout with struct irq_work 22 */ 23 struct __call_single_data { 24 union { 25 struct __call_single_node node; 26 struct { 27 struct llist_node llist; 28 unsigned int flags; 29 }; 30 }; 31 smp_call_func_t func; 32 void *info; 33 }; 34 35 /* Use __aligned() to avoid to use 2 cache lines for 1 csd */ 36 typedef struct __call_single_data call_single_data_t 37 __aligned(sizeof(struct __call_single_data)); 38 39 /* 40 * Enqueue a llist_node on the call_single_queue; be very careful, read 41 * flush_smp_call_function_queue() in detail. 42 */ 43 extern void __smp_call_single_queue(int cpu, struct llist_node *node); 44 45 /* total number of cpus in this system (may exceed NR_CPUS) */ 46 extern unsigned int total_cpus; 47 48 int smp_call_function_single(int cpuid, smp_call_func_t func, void *info, 49 int wait); 50 51 /* 52 * Call a function on all processors 53 */ 54 void on_each_cpu(smp_call_func_t func, void *info, int wait); 55 56 /* 57 * Call a function on processors specified by mask, which might include 58 * the local one. 59 */ 60 void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func, 61 void *info, bool wait); 62 63 /* 64 * Call a function on each processor for which the supplied function 65 * cond_func returns a positive value. This may include the local 66 * processor. 67 */ 68 void on_each_cpu_cond(smp_cond_func_t cond_func, smp_call_func_t func, 69 void *info, bool wait); 70 71 void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func, 72 void *info, bool wait, const struct cpumask *mask); 73 74 int smp_call_function_single_async(int cpu, call_single_data_t *csd); 75 76 #ifdef CONFIG_SMP 77 78 #include <linux/preempt.h> 79 #include <linux/kernel.h> 80 #include <linux/compiler.h> 81 #include <linux/thread_info.h> 82 #include <asm/smp.h> 83 84 /* 85 * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc. 86 * (defined in asm header): 87 */ 88 89 /* 90 * stops all CPUs but the current one: 91 */ 92 extern void smp_send_stop(void); 93 94 /* 95 * sends a 'reschedule' event to another CPU: 96 */ 97 extern void smp_send_reschedule(int cpu); 98 99 100 /* 101 * Prepare machine for booting other CPUs. 102 */ 103 extern void smp_prepare_cpus(unsigned int max_cpus); 104 105 /* 106 * Bring a CPU up 107 */ 108 extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle); 109 110 /* 111 * Final polishing of CPUs 112 */ 113 extern void smp_cpus_done(unsigned int max_cpus); 114 115 /* 116 * Call a function on all other processors 117 */ 118 void smp_call_function(smp_call_func_t func, void *info, int wait); 119 void smp_call_function_many(const struct cpumask *mask, 120 smp_call_func_t func, void *info, bool wait); 121 122 int smp_call_function_any(const struct cpumask *mask, 123 smp_call_func_t func, void *info, int wait); 124 125 void kick_all_cpus_sync(void); 126 void wake_up_all_idle_cpus(void); 127 128 /* 129 * Generic and arch helpers 130 */ 131 void __init call_function_init(void); 132 void generic_smp_call_function_single_interrupt(void); 133 #define generic_smp_call_function_interrupt \ 134 generic_smp_call_function_single_interrupt 135 136 /* 137 * Mark the boot cpu "online" so that it can call console drivers in 138 * printk() and can access its per-cpu storage. 139 */ 140 void smp_prepare_boot_cpu(void); 141 142 extern unsigned int setup_max_cpus; 143 extern void __init setup_nr_cpu_ids(void); 144 extern void __init smp_init(void); 145 146 extern int __boot_cpu_id; 147 148 static inline int get_boot_cpu_id(void) 149 { 150 return __boot_cpu_id; 151 } 152 153 #else /* !SMP */ 154 155 static inline void smp_send_stop(void) { } 156 157 /* 158 * These macros fold the SMP functionality into a single CPU system 159 */ 160 #define raw_smp_processor_id() 0 161 static inline void up_smp_call_function(smp_call_func_t func, void *info) 162 { 163 } 164 #define smp_call_function(func, info, wait) \ 165 (up_smp_call_function(func, info)) 166 167 static inline void smp_send_reschedule(int cpu) { } 168 #define smp_prepare_boot_cpu() do {} while (0) 169 #define smp_call_function_many(mask, func, info, wait) \ 170 (up_smp_call_function(func, info)) 171 static inline void call_function_init(void) { } 172 173 static inline int 174 smp_call_function_any(const struct cpumask *mask, smp_call_func_t func, 175 void *info, int wait) 176 { 177 return smp_call_function_single(0, func, info, wait); 178 } 179 180 static inline void kick_all_cpus_sync(void) { } 181 static inline void wake_up_all_idle_cpus(void) { } 182 183 #ifdef CONFIG_UP_LATE_INIT 184 extern void __init up_late_init(void); 185 static inline void smp_init(void) { up_late_init(); } 186 #else 187 static inline void smp_init(void) { } 188 #endif 189 190 static inline int get_boot_cpu_id(void) 191 { 192 return 0; 193 } 194 195 #endif /* !SMP */ 196 197 /** 198 * raw_processor_id() - get the current (unstable) CPU id 199 * 200 * For then you know what you are doing and need an unstable 201 * CPU id. 202 */ 203 204 /** 205 * smp_processor_id() - get the current (stable) CPU id 206 * 207 * This is the normal accessor to the CPU id and should be used 208 * whenever possible. 209 * 210 * The CPU id is stable when: 211 * 212 * - IRQs are disabled; 213 * - preemption is disabled; 214 * - the task is CPU affine. 215 * 216 * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN 217 * when smp_processor_id() is used when the CPU id is not stable. 218 */ 219 220 /* 221 * Allow the architecture to differentiate between a stable and unstable read. 222 * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a 223 * regular asm read for the stable. 224 */ 225 #ifndef __smp_processor_id 226 #define __smp_processor_id(x) raw_smp_processor_id(x) 227 #endif 228 229 #ifdef CONFIG_DEBUG_PREEMPT 230 extern unsigned int debug_smp_processor_id(void); 231 # define smp_processor_id() debug_smp_processor_id() 232 #else 233 # define smp_processor_id() __smp_processor_id() 234 #endif 235 236 #define get_cpu() ({ preempt_disable(); __smp_processor_id(); }) 237 #define put_cpu() preempt_enable() 238 239 /* 240 * Callback to arch code if there's nosmp or maxcpus=0 on the 241 * boot command line: 242 */ 243 extern void arch_disable_smp_support(void); 244 245 extern void arch_thaw_secondary_cpus_begin(void); 246 extern void arch_thaw_secondary_cpus_end(void); 247 248 void smp_setup_processor_id(void); 249 250 int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, 251 bool phys); 252 253 /* SMP core functions */ 254 int smpcfd_prepare_cpu(unsigned int cpu); 255 int smpcfd_dead_cpu(unsigned int cpu); 256 int smpcfd_dying_cpu(unsigned int cpu); 257 258 #endif /* __LINUX_SMP_H */ 259