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. <alan@redhat.com> 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 /* 54 * Call a function on all processors 55 */ 56 void on_each_cpu(smp_call_func_t func, void *info, int wait); 57 58 /* 59 * Call a function on processors specified by mask, which might include 60 * the local one. 61 */ 62 void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func, 63 void *info, bool wait); 64 65 /* 66 * Call a function on each processor for which the supplied function 67 * cond_func returns a positive value. This may include the local 68 * processor. 69 */ 70 void on_each_cpu_cond(smp_cond_func_t cond_func, smp_call_func_t func, 71 void *info, bool wait); 72 73 void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func, 74 void *info, bool wait, const struct cpumask *mask); 75 76 int smp_call_function_single_async(int cpu, call_single_data_t *csd); 77 78 #ifdef CONFIG_SMP 79 80 #include <linux/preempt.h> 81 #include <linux/kernel.h> 82 #include <linux/compiler.h> 83 #include <linux/thread_info.h> 84 #include <asm/smp.h> 85 86 /* 87 * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc. 88 * (defined in asm header): 89 */ 90 91 /* 92 * stops all CPUs but the current one: 93 */ 94 extern void smp_send_stop(void); 95 96 /* 97 * sends a 'reschedule' event to another CPU: 98 */ 99 extern void smp_send_reschedule(int cpu); 100 101 102 /* 103 * Prepare machine for booting other CPUs. 104 */ 105 extern void smp_prepare_cpus(unsigned int max_cpus); 106 107 /* 108 * Bring a CPU up 109 */ 110 extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle); 111 112 /* 113 * Final polishing of CPUs 114 */ 115 extern void smp_cpus_done(unsigned int max_cpus); 116 117 /* 118 * Call a function on all other processors 119 */ 120 void smp_call_function(smp_call_func_t func, void *info, int wait); 121 void smp_call_function_many(const struct cpumask *mask, 122 smp_call_func_t func, void *info, bool wait); 123 124 int smp_call_function_any(const struct cpumask *mask, 125 smp_call_func_t func, void *info, int wait); 126 127 void kick_all_cpus_sync(void); 128 void wake_up_all_idle_cpus(void); 129 130 /* 131 * Generic and arch helpers 132 */ 133 void __init call_function_init(void); 134 void generic_smp_call_function_single_interrupt(void); 135 #define generic_smp_call_function_interrupt \ 136 generic_smp_call_function_single_interrupt 137 138 /* 139 * Mark the boot cpu "online" so that it can call console drivers in 140 * printk() and can access its per-cpu storage. 141 */ 142 void smp_prepare_boot_cpu(void); 143 144 extern unsigned int setup_max_cpus; 145 extern void __init setup_nr_cpu_ids(void); 146 extern void __init smp_init(void); 147 148 extern int __boot_cpu_id; 149 150 static inline int get_boot_cpu_id(void) 151 { 152 return __boot_cpu_id; 153 } 154 155 #else /* !SMP */ 156 157 static inline void smp_send_stop(void) { } 158 159 /* 160 * These macros fold the SMP functionality into a single CPU system 161 */ 162 #define raw_smp_processor_id() 0 163 static inline void up_smp_call_function(smp_call_func_t func, void *info) 164 { 165 } 166 #define smp_call_function(func, info, wait) \ 167 (up_smp_call_function(func, info)) 168 169 static inline void smp_send_reschedule(int cpu) { } 170 #define smp_prepare_boot_cpu() do {} while (0) 171 #define smp_call_function_many(mask, func, info, wait) \ 172 (up_smp_call_function(func, info)) 173 static inline void call_function_init(void) { } 174 175 static inline int 176 smp_call_function_any(const struct cpumask *mask, smp_call_func_t func, 177 void *info, int wait) 178 { 179 return smp_call_function_single(0, func, info, wait); 180 } 181 182 static inline void kick_all_cpus_sync(void) { } 183 static inline void wake_up_all_idle_cpus(void) { } 184 185 #ifdef CONFIG_UP_LATE_INIT 186 extern void __init up_late_init(void); 187 static inline void smp_init(void) { up_late_init(); } 188 #else 189 static inline void smp_init(void) { } 190 #endif 191 192 static inline int get_boot_cpu_id(void) 193 { 194 return 0; 195 } 196 197 #endif /* !SMP */ 198 199 /** 200 * raw_processor_id() - get the current (unstable) CPU id 201 * 202 * For then you know what you are doing and need an unstable 203 * CPU id. 204 */ 205 206 /** 207 * smp_processor_id() - get the current (stable) CPU id 208 * 209 * This is the normal accessor to the CPU id and should be used 210 * whenever possible. 211 * 212 * The CPU id is stable when: 213 * 214 * - IRQs are disabled; 215 * - preemption is disabled; 216 * - the task is CPU affine. 217 * 218 * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN 219 * when smp_processor_id() is used when the CPU id is not stable. 220 */ 221 222 /* 223 * Allow the architecture to differentiate between a stable and unstable read. 224 * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a 225 * regular asm read for the stable. 226 */ 227 #ifndef __smp_processor_id 228 #define __smp_processor_id(x) raw_smp_processor_id(x) 229 #endif 230 231 #ifdef CONFIG_DEBUG_PREEMPT 232 extern unsigned int debug_smp_processor_id(void); 233 # define smp_processor_id() debug_smp_processor_id() 234 #else 235 # define smp_processor_id() __smp_processor_id() 236 #endif 237 238 #define get_cpu() ({ preempt_disable(); __smp_processor_id(); }) 239 #define put_cpu() preempt_enable() 240 241 /* 242 * Callback to arch code if there's nosmp or maxcpus=0 on the 243 * boot command line: 244 */ 245 extern void arch_disable_smp_support(void); 246 247 extern void arch_thaw_secondary_cpus_begin(void); 248 extern void arch_thaw_secondary_cpus_end(void); 249 250 void smp_setup_processor_id(void); 251 252 int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, 253 bool phys); 254 255 /* SMP core functions */ 256 int smpcfd_prepare_cpu(unsigned int cpu); 257 int smpcfd_dead_cpu(unsigned int cpu); 258 int smpcfd_dying_cpu(unsigned int cpu); 259 260 #endif /* __LINUX_SMP_H */ 261