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 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, struct __call_single_data *csd); 57 58 /* 59 * Cpus stopping functions in panic. All have default weak definitions. 60 * Architecture-dependent code may override them. 61 */ 62 void panic_smp_self_stop(void); 63 void nmi_panic_self_stop(struct pt_regs *regs); 64 void crash_smp_send_stop(void); 65 66 /* 67 * Call a function on all processors 68 */ 69 static inline void on_each_cpu(smp_call_func_t func, void *info, int wait) 70 { 71 on_each_cpu_cond_mask(NULL, func, info, wait, cpu_online_mask); 72 } 73 74 /** 75 * on_each_cpu_mask(): Run a function on processors specified by 76 * cpumask, which may include the local processor. 77 * @mask: The set of cpus to run on (only runs on online subset). 78 * @func: The function to run. This must be fast and non-blocking. 79 * @info: An arbitrary pointer to pass to the function. 80 * @wait: If true, wait (atomically) until function has completed 81 * on other CPUs. 82 * 83 * If @wait is true, then returns once @func has returned. 84 * 85 * You must not call this function with disabled interrupts or from a 86 * hardware interrupt handler or from a bottom half handler. The 87 * exception is that it may be used during early boot while 88 * early_boot_irqs_disabled is set. 89 */ 90 static inline void on_each_cpu_mask(const struct cpumask *mask, 91 smp_call_func_t func, void *info, bool wait) 92 { 93 on_each_cpu_cond_mask(NULL, func, info, wait, mask); 94 } 95 96 /* 97 * Call a function on each processor for which the supplied function 98 * cond_func returns a positive value. This may include the local 99 * processor. May be used during early boot while early_boot_irqs_disabled is 100 * set. Use local_irq_save/restore() instead of local_irq_disable/enable(). 101 */ 102 static inline void on_each_cpu_cond(smp_cond_func_t cond_func, 103 smp_call_func_t func, void *info, bool wait) 104 { 105 on_each_cpu_cond_mask(cond_func, func, info, wait, cpu_online_mask); 106 } 107 108 #ifdef CONFIG_SMP 109 110 #include <linux/preempt.h> 111 #include <linux/compiler.h> 112 #include <linux/thread_info.h> 113 #include <asm/smp.h> 114 115 /* 116 * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc. 117 * (defined in asm header): 118 */ 119 120 /* 121 * stops all CPUs but the current one: 122 */ 123 extern void smp_send_stop(void); 124 125 /* 126 * sends a 'reschedule' event to another CPU: 127 */ 128 extern void smp_send_reschedule(int cpu); 129 130 131 /* 132 * Prepare machine for booting other CPUs. 133 */ 134 extern void smp_prepare_cpus(unsigned int max_cpus); 135 136 /* 137 * Bring a CPU up 138 */ 139 extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle); 140 141 /* 142 * Final polishing of CPUs 143 */ 144 extern void smp_cpus_done(unsigned int max_cpus); 145 146 /* 147 * Call a function on all other processors 148 */ 149 void smp_call_function(smp_call_func_t func, void *info, int wait); 150 void smp_call_function_many(const struct cpumask *mask, 151 smp_call_func_t func, void *info, bool wait); 152 153 int smp_call_function_any(const struct cpumask *mask, 154 smp_call_func_t func, void *info, int wait); 155 156 void kick_all_cpus_sync(void); 157 void wake_up_all_idle_cpus(void); 158 159 /* 160 * Generic and arch helpers 161 */ 162 void __init call_function_init(void); 163 void generic_smp_call_function_single_interrupt(void); 164 #define generic_smp_call_function_interrupt \ 165 generic_smp_call_function_single_interrupt 166 167 /* 168 * Mark the boot cpu "online" so that it can call console drivers in 169 * printk() and can access its per-cpu storage. 170 */ 171 void smp_prepare_boot_cpu(void); 172 173 extern unsigned int setup_max_cpus; 174 extern void __init setup_nr_cpu_ids(void); 175 extern void __init smp_init(void); 176 177 extern int __boot_cpu_id; 178 179 static inline int get_boot_cpu_id(void) 180 { 181 return __boot_cpu_id; 182 } 183 184 #else /* !SMP */ 185 186 static inline void smp_send_stop(void) { } 187 188 /* 189 * These macros fold the SMP functionality into a single CPU system 190 */ 191 #define raw_smp_processor_id() 0 192 static inline void up_smp_call_function(smp_call_func_t func, void *info) 193 { 194 } 195 #define smp_call_function(func, info, wait) \ 196 (up_smp_call_function(func, info)) 197 198 static inline void smp_send_reschedule(int cpu) { } 199 #define smp_prepare_boot_cpu() do {} while (0) 200 #define smp_call_function_many(mask, func, info, wait) \ 201 (up_smp_call_function(func, info)) 202 static inline void call_function_init(void) { } 203 204 static inline int 205 smp_call_function_any(const struct cpumask *mask, smp_call_func_t func, 206 void *info, int wait) 207 { 208 return smp_call_function_single(0, func, info, wait); 209 } 210 211 static inline void kick_all_cpus_sync(void) { } 212 static inline void wake_up_all_idle_cpus(void) { } 213 214 #ifdef CONFIG_UP_LATE_INIT 215 extern void __init up_late_init(void); 216 static inline void smp_init(void) { up_late_init(); } 217 #else 218 static inline void smp_init(void) { } 219 #endif 220 221 static inline int get_boot_cpu_id(void) 222 { 223 return 0; 224 } 225 226 #endif /* !SMP */ 227 228 /** 229 * raw_processor_id() - get the current (unstable) CPU id 230 * 231 * For then you know what you are doing and need an unstable 232 * CPU id. 233 */ 234 235 /** 236 * smp_processor_id() - get the current (stable) CPU id 237 * 238 * This is the normal accessor to the CPU id and should be used 239 * whenever possible. 240 * 241 * The CPU id is stable when: 242 * 243 * - IRQs are disabled; 244 * - preemption is disabled; 245 * - the task is CPU affine. 246 * 247 * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN 248 * when smp_processor_id() is used when the CPU id is not stable. 249 */ 250 251 /* 252 * Allow the architecture to differentiate between a stable and unstable read. 253 * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a 254 * regular asm read for the stable. 255 */ 256 #ifndef __smp_processor_id 257 #define __smp_processor_id(x) raw_smp_processor_id(x) 258 #endif 259 260 #ifdef CONFIG_DEBUG_PREEMPT 261 extern unsigned int debug_smp_processor_id(void); 262 # define smp_processor_id() debug_smp_processor_id() 263 #else 264 # define smp_processor_id() __smp_processor_id() 265 #endif 266 267 #define get_cpu() ({ preempt_disable(); __smp_processor_id(); }) 268 #define put_cpu() preempt_enable() 269 270 /* 271 * Callback to arch code if there's nosmp or maxcpus=0 on the 272 * boot command line: 273 */ 274 extern void arch_disable_smp_support(void); 275 276 extern void arch_thaw_secondary_cpus_begin(void); 277 extern void arch_thaw_secondary_cpus_end(void); 278 279 void smp_setup_processor_id(void); 280 281 int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, 282 bool phys); 283 284 /* SMP core functions */ 285 int smpcfd_prepare_cpu(unsigned int cpu); 286 int smpcfd_dead_cpu(unsigned int cpu); 287 int smpcfd_dying_cpu(unsigned int cpu); 288 289 #endif /* __LINUX_SMP_H */ 290