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 struct __call_single_node node; 25 smp_call_func_t func; 26 void *info; 27 }; 28 29 #define CSD_INIT(_func, _info) \ 30 (struct __call_single_data){ .func = (_func), .info = (_info), } 31 32 /* Use __aligned() to avoid to use 2 cache lines for 1 csd */ 33 typedef struct __call_single_data call_single_data_t 34 __aligned(sizeof(struct __call_single_data)); 35 36 #define INIT_CSD(_csd, _func, _info) \ 37 do { \ 38 *(_csd) = CSD_INIT((_func), (_info)); \ 39 } while (0) 40 41 /* 42 * Enqueue a llist_node on the call_single_queue; be very careful, read 43 * flush_smp_call_function_queue() in detail. 44 */ 45 extern void __smp_call_single_queue(int cpu, struct llist_node *node); 46 47 /* total number of cpus in this system (may exceed NR_CPUS) */ 48 extern unsigned int total_cpus; 49 50 int smp_call_function_single(int cpuid, smp_call_func_t func, void *info, 51 int wait); 52 53 void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func, 54 void *info, bool wait, const struct cpumask *mask); 55 56 int smp_call_function_single_async(int cpu, call_single_data_t *csd); 57 58 /* 59 * Call a function on all processors 60 */ 61 static inline void on_each_cpu(smp_call_func_t func, void *info, int wait) 62 { 63 on_each_cpu_cond_mask(NULL, func, info, wait, cpu_online_mask); 64 } 65 66 /** 67 * on_each_cpu_mask(): Run a function on processors specified by 68 * cpumask, which may include the local processor. 69 * @mask: The set of cpus to run on (only runs on online subset). 70 * @func: The function to run. This must be fast and non-blocking. 71 * @info: An arbitrary pointer to pass to the function. 72 * @wait: If true, wait (atomically) until function has completed 73 * on other CPUs. 74 * 75 * If @wait is true, then returns once @func has returned. 76 * 77 * You must not call this function with disabled interrupts or from a 78 * hardware interrupt handler or from a bottom half handler. The 79 * exception is that it may be used during early boot while 80 * early_boot_irqs_disabled is set. 81 */ 82 static inline void on_each_cpu_mask(const struct cpumask *mask, 83 smp_call_func_t func, void *info, bool wait) 84 { 85 on_each_cpu_cond_mask(NULL, func, info, wait, mask); 86 } 87 88 /* 89 * Call a function on each processor for which the supplied function 90 * cond_func returns a positive value. This may include the local 91 * processor. May be used during early boot while early_boot_irqs_disabled is 92 * set. Use local_irq_save/restore() instead of local_irq_disable/enable(). 93 */ 94 static inline void on_each_cpu_cond(smp_cond_func_t cond_func, 95 smp_call_func_t func, void *info, bool wait) 96 { 97 on_each_cpu_cond_mask(cond_func, func, info, wait, cpu_online_mask); 98 } 99 100 #ifdef CONFIG_SMP 101 102 #include <linux/preempt.h> 103 #include <linux/kernel.h> 104 #include <linux/compiler.h> 105 #include <linux/thread_info.h> 106 #include <asm/smp.h> 107 108 /* 109 * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc. 110 * (defined in asm header): 111 */ 112 113 /* 114 * stops all CPUs but the current one: 115 */ 116 extern void smp_send_stop(void); 117 118 /* 119 * sends a 'reschedule' event to another CPU: 120 */ 121 extern void smp_send_reschedule(int cpu); 122 123 124 /* 125 * Prepare machine for booting other CPUs. 126 */ 127 extern void smp_prepare_cpus(unsigned int max_cpus); 128 129 /* 130 * Bring a CPU up 131 */ 132 extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle); 133 134 /* 135 * Final polishing of CPUs 136 */ 137 extern void smp_cpus_done(unsigned int max_cpus); 138 139 /* 140 * Call a function on all other processors 141 */ 142 void smp_call_function(smp_call_func_t func, void *info, int wait); 143 void smp_call_function_many(const struct cpumask *mask, 144 smp_call_func_t func, void *info, bool wait); 145 146 int smp_call_function_any(const struct cpumask *mask, 147 smp_call_func_t func, void *info, int wait); 148 149 void kick_all_cpus_sync(void); 150 void wake_up_all_idle_cpus(void); 151 152 /* 153 * Generic and arch helpers 154 */ 155 void __init call_function_init(void); 156 void generic_smp_call_function_single_interrupt(void); 157 #define generic_smp_call_function_interrupt \ 158 generic_smp_call_function_single_interrupt 159 160 /* 161 * Mark the boot cpu "online" so that it can call console drivers in 162 * printk() and can access its per-cpu storage. 163 */ 164 void smp_prepare_boot_cpu(void); 165 166 extern unsigned int setup_max_cpus; 167 extern void __init setup_nr_cpu_ids(void); 168 extern void __init smp_init(void); 169 170 extern int __boot_cpu_id; 171 172 static inline int get_boot_cpu_id(void) 173 { 174 return __boot_cpu_id; 175 } 176 177 #else /* !SMP */ 178 179 static inline void smp_send_stop(void) { } 180 181 /* 182 * These macros fold the SMP functionality into a single CPU system 183 */ 184 #define raw_smp_processor_id() 0 185 static inline void up_smp_call_function(smp_call_func_t func, void *info) 186 { 187 } 188 #define smp_call_function(func, info, wait) \ 189 (up_smp_call_function(func, info)) 190 191 static inline void smp_send_reschedule(int cpu) { } 192 #define smp_prepare_boot_cpu() do {} while (0) 193 #define smp_call_function_many(mask, func, info, wait) \ 194 (up_smp_call_function(func, info)) 195 static inline void call_function_init(void) { } 196 197 static inline int 198 smp_call_function_any(const struct cpumask *mask, smp_call_func_t func, 199 void *info, int wait) 200 { 201 return smp_call_function_single(0, func, info, wait); 202 } 203 204 static inline void kick_all_cpus_sync(void) { } 205 static inline void wake_up_all_idle_cpus(void) { } 206 207 #ifdef CONFIG_UP_LATE_INIT 208 extern void __init up_late_init(void); 209 static inline void smp_init(void) { up_late_init(); } 210 #else 211 static inline void smp_init(void) { } 212 #endif 213 214 static inline int get_boot_cpu_id(void) 215 { 216 return 0; 217 } 218 219 #endif /* !SMP */ 220 221 /** 222 * raw_processor_id() - get the current (unstable) CPU id 223 * 224 * For then you know what you are doing and need an unstable 225 * CPU id. 226 */ 227 228 /** 229 * smp_processor_id() - get the current (stable) CPU id 230 * 231 * This is the normal accessor to the CPU id and should be used 232 * whenever possible. 233 * 234 * The CPU id is stable when: 235 * 236 * - IRQs are disabled; 237 * - preemption is disabled; 238 * - the task is CPU affine. 239 * 240 * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN 241 * when smp_processor_id() is used when the CPU id is not stable. 242 */ 243 244 /* 245 * Allow the architecture to differentiate between a stable and unstable read. 246 * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a 247 * regular asm read for the stable. 248 */ 249 #ifndef __smp_processor_id 250 #define __smp_processor_id(x) raw_smp_processor_id(x) 251 #endif 252 253 #ifdef CONFIG_DEBUG_PREEMPT 254 extern unsigned int debug_smp_processor_id(void); 255 # define smp_processor_id() debug_smp_processor_id() 256 #else 257 # define smp_processor_id() __smp_processor_id() 258 #endif 259 260 #define get_cpu() ({ preempt_disable(); __smp_processor_id(); }) 261 #define put_cpu() preempt_enable() 262 263 /* 264 * Callback to arch code if there's nosmp or maxcpus=0 on the 265 * boot command line: 266 */ 267 extern void arch_disable_smp_support(void); 268 269 extern void arch_thaw_secondary_cpus_begin(void); 270 extern void arch_thaw_secondary_cpus_end(void); 271 272 void smp_setup_processor_id(void); 273 274 int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, 275 bool phys); 276 277 /* SMP core functions */ 278 int smpcfd_prepare_cpu(unsigned int cpu); 279 int smpcfd_dead_cpu(unsigned int cpu); 280 int smpcfd_dying_cpu(unsigned int cpu); 281 282 #endif /* __LINUX_SMP_H */ 283