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, call_single_data_t *csd); 57 58 /* 59 * Cpus stopping functions in panic. All have default weak definitions. 60 * Architecture-dependent code may override them. 61 */ 62 void __noreturn panic_smp_self_stop(void); 63 void __noreturn 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 /* 109 * Architecture specific boot CPU setup. Defined as empty weak function in 110 * init/main.c. Architectures can override it. 111 */ 112 void __init smp_prepare_boot_cpu(void); 113 114 #ifdef CONFIG_SMP 115 116 #include <linux/preempt.h> 117 #include <linux/compiler.h> 118 #include <linux/thread_info.h> 119 #include <asm/smp.h> 120 121 /* 122 * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc. 123 * (defined in asm header): 124 */ 125 126 /* 127 * stops all CPUs but the current one: 128 */ 129 extern void smp_send_stop(void); 130 131 /* 132 * sends a 'reschedule' event to another CPU: 133 */ 134 extern void arch_smp_send_reschedule(int cpu); 135 /* 136 * scheduler_ipi() is inline so can't be passed as callback reason, but the 137 * callsite IP should be sufficient for root-causing IPIs sent from here. 138 */ 139 #define smp_send_reschedule(cpu) ({ \ 140 trace_ipi_send_cpu(cpu, _RET_IP_, NULL); \ 141 arch_smp_send_reschedule(cpu); \ 142 }) 143 144 /* 145 * Prepare machine for booting other CPUs. 146 */ 147 extern void smp_prepare_cpus(unsigned int max_cpus); 148 149 /* 150 * Bring a CPU up 151 */ 152 extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle); 153 154 /* 155 * Final polishing of CPUs 156 */ 157 extern void smp_cpus_done(unsigned int max_cpus); 158 159 /* 160 * Call a function on all other processors 161 */ 162 void smp_call_function(smp_call_func_t func, void *info, int wait); 163 void smp_call_function_many(const struct cpumask *mask, 164 smp_call_func_t func, void *info, bool wait); 165 166 int smp_call_function_any(const struct cpumask *mask, 167 smp_call_func_t func, void *info, int wait); 168 169 void kick_all_cpus_sync(void); 170 void wake_up_all_idle_cpus(void); 171 bool cpus_peek_for_pending_ipi(const struct cpumask *mask); 172 173 /* 174 * Generic and arch helpers 175 */ 176 void __init call_function_init(void); 177 void generic_smp_call_function_single_interrupt(void); 178 #define generic_smp_call_function_interrupt \ 179 generic_smp_call_function_single_interrupt 180 181 extern unsigned int setup_max_cpus; 182 extern void __init setup_nr_cpu_ids(void); 183 extern void __init smp_init(void); 184 185 extern int __boot_cpu_id; 186 187 static inline int get_boot_cpu_id(void) 188 { 189 return __boot_cpu_id; 190 } 191 192 #else /* !SMP */ 193 194 static inline void smp_send_stop(void) { } 195 196 /* 197 * These macros fold the SMP functionality into a single CPU system 198 */ 199 #define raw_smp_processor_id() 0 200 static inline void up_smp_call_function(smp_call_func_t func, void *info) 201 { 202 } 203 #define smp_call_function(func, info, wait) \ 204 (up_smp_call_function(func, info)) 205 206 static inline void smp_send_reschedule(int cpu) { } 207 #define smp_call_function_many(mask, func, info, wait) \ 208 (up_smp_call_function(func, info)) 209 static inline void call_function_init(void) { } 210 211 static inline int 212 smp_call_function_any(const struct cpumask *mask, smp_call_func_t func, 213 void *info, int wait) 214 { 215 return smp_call_function_single(0, func, info, wait); 216 } 217 218 static inline void kick_all_cpus_sync(void) { } 219 static inline void wake_up_all_idle_cpus(void) { } 220 static inline bool cpus_peek_for_pending_ipi(const struct cpumask *mask) 221 { 222 return false; 223 } 224 225 #define setup_max_cpus 0 226 227 #ifdef CONFIG_UP_LATE_INIT 228 extern void __init up_late_init(void); 229 static __always_inline void smp_init(void) { up_late_init(); } 230 #else 231 static inline void smp_init(void) { } 232 #endif 233 234 static inline int get_boot_cpu_id(void) 235 { 236 return 0; 237 } 238 239 #endif /* !SMP */ 240 241 /** 242 * raw_smp_processor_id() - get the current (unstable) CPU id 243 * 244 * For then you know what you are doing and need an unstable 245 * CPU id. 246 */ 247 248 /** 249 * smp_processor_id() - get the current (stable) CPU id 250 * 251 * This is the normal accessor to the CPU id and should be used 252 * whenever possible. 253 * 254 * The CPU id is stable when: 255 * 256 * - IRQs are disabled; 257 * - preemption is disabled; 258 * - the task is CPU affine. 259 * 260 * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN 261 * when smp_processor_id() is used when the CPU id is not stable. 262 */ 263 264 /* 265 * Allow the architecture to differentiate between a stable and unstable read. 266 * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a 267 * regular asm read for the stable. 268 */ 269 #ifndef __smp_processor_id 270 #define __smp_processor_id() raw_smp_processor_id() 271 #endif 272 273 #ifdef CONFIG_DEBUG_PREEMPT 274 extern unsigned int debug_smp_processor_id(void); 275 # define smp_processor_id() debug_smp_processor_id() 276 #else 277 # define smp_processor_id() __smp_processor_id() 278 #endif 279 280 #define get_cpu() ({ preempt_disable(); __smp_processor_id(); }) 281 #define put_cpu() preempt_enable() 282 283 /* 284 * Callback to arch code if there's nosmp or maxcpus=0 on the 285 * boot command line: 286 */ 287 extern void arch_disable_smp_support(void); 288 289 extern void arch_thaw_secondary_cpus_begin(void); 290 extern void arch_thaw_secondary_cpus_end(void); 291 292 void smp_setup_processor_id(void); 293 294 int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, 295 bool phys); 296 297 /* SMP core functions */ 298 int smpcfd_prepare_cpu(unsigned int cpu); 299 int smpcfd_dead_cpu(unsigned int cpu); 300 int smpcfd_dying_cpu(unsigned int cpu); 301 302 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG 303 bool csd_lock_is_stuck(void); 304 #else 305 static inline bool csd_lock_is_stuck(void) { return false; } 306 #endif 307 308 #endif /* __LINUX_SMP_H */ 309