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 17typedef void (*smp_call_func_t)(void *info); 18typedef bool (*smp_cond_func_t)(int cpu, void *info); 19 20/* 21 * structure shares (partial) layout with struct irq_work 22 */ 23struct __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 */ 33typedef struct __call_single_data call_single_data_t 34 __aligned(sizeof(struct __call_single_data)); 35 36#define INIT_CSD(_csd, _func, _info) \ 37do { \ 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 */ 45extern void __smp_call_single_queue(int cpu, struct llist_node *node); 46 47/* total number of cpus in this system (may exceed NR_CPUS) */ 48extern unsigned int total_cpus; 49 50int smp_call_function_single(int cpuid, smp_call_func_t func, void *info, 51 int wait); 52 53void 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 56int 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 */ 62void __noreturn panic_smp_self_stop(void); 63void __noreturn nmi_panic_self_stop(struct pt_regs *regs); 64void crash_smp_send_stop(void); 65 66/* 67 * Call a function on all processors 68 */ 69static 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 */ 90static 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 */ 102static 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 */ 112void 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 */ 129extern void smp_send_stop(void); 130 131/* 132 * sends a 'reschedule' event to another CPU: 133 */ 134extern 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 */ 147extern void smp_prepare_cpus(unsigned int max_cpus); 148 149/* 150 * Bring a CPU up 151 */ 152extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle); 153 154/* 155 * Final polishing of CPUs 156 */ 157extern void smp_cpus_done(unsigned int max_cpus); 158 159/* 160 * Call a function on all other processors 161 */ 162void smp_call_function(smp_call_func_t func, void *info, int wait); 163void smp_call_function_many(const struct cpumask *mask, 164 smp_call_func_t func, void *info, bool wait); 165 166int smp_call_function_any(const struct cpumask *mask, 167 smp_call_func_t func, void *info, int wait); 168 169void kick_all_cpus_sync(void); 170void wake_up_all_idle_cpus(void); 171 172/* 173 * Generic and arch helpers 174 */ 175void __init call_function_init(void); 176void generic_smp_call_function_single_interrupt(void); 177#define generic_smp_call_function_interrupt \ 178 generic_smp_call_function_single_interrupt 179 180extern unsigned int setup_max_cpus; 181extern void __init setup_nr_cpu_ids(void); 182extern void __init smp_init(void); 183 184extern int __boot_cpu_id; 185 186static inline int get_boot_cpu_id(void) 187{ 188 return __boot_cpu_id; 189} 190 191#else /* !SMP */ 192 193static inline void smp_send_stop(void) { } 194 195/* 196 * These macros fold the SMP functionality into a single CPU system 197 */ 198#define raw_smp_processor_id() 0 199static inline void up_smp_call_function(smp_call_func_t func, void *info) 200{ 201} 202#define smp_call_function(func, info, wait) \ 203 (up_smp_call_function(func, info)) 204 205static inline void smp_send_reschedule(int cpu) { } 206#define smp_call_function_many(mask, func, info, wait) \ 207 (up_smp_call_function(func, info)) 208static inline void call_function_init(void) { } 209 210static inline int 211smp_call_function_any(const struct cpumask *mask, smp_call_func_t func, 212 void *info, int wait) 213{ 214 return smp_call_function_single(0, func, info, wait); 215} 216 217static inline void kick_all_cpus_sync(void) { } 218static inline void wake_up_all_idle_cpus(void) { } 219 220#define setup_max_cpus 0 221 222#ifdef CONFIG_UP_LATE_INIT 223extern void __init up_late_init(void); 224static inline void smp_init(void) { up_late_init(); } 225#else 226static inline void smp_init(void) { } 227#endif 228 229static inline int get_boot_cpu_id(void) 230{ 231 return 0; 232} 233 234#endif /* !SMP */ 235 236/** 237 * raw_processor_id() - get the current (unstable) CPU id 238 * 239 * For then you know what you are doing and need an unstable 240 * CPU id. 241 */ 242 243/** 244 * smp_processor_id() - get the current (stable) CPU id 245 * 246 * This is the normal accessor to the CPU id and should be used 247 * whenever possible. 248 * 249 * The CPU id is stable when: 250 * 251 * - IRQs are disabled; 252 * - preemption is disabled; 253 * - the task is CPU affine. 254 * 255 * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN 256 * when smp_processor_id() is used when the CPU id is not stable. 257 */ 258 259/* 260 * Allow the architecture to differentiate between a stable and unstable read. 261 * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a 262 * regular asm read for the stable. 263 */ 264#ifndef __smp_processor_id 265#define __smp_processor_id() raw_smp_processor_id() 266#endif 267 268#ifdef CONFIG_DEBUG_PREEMPT 269 extern unsigned int debug_smp_processor_id(void); 270# define smp_processor_id() debug_smp_processor_id() 271#else 272# define smp_processor_id() __smp_processor_id() 273#endif 274 275#define get_cpu() ({ preempt_disable(); __smp_processor_id(); }) 276#define put_cpu() preempt_enable() 277 278/* 279 * Callback to arch code if there's nosmp or maxcpus=0 on the 280 * boot command line: 281 */ 282extern void arch_disable_smp_support(void); 283 284extern void arch_thaw_secondary_cpus_begin(void); 285extern void arch_thaw_secondary_cpus_end(void); 286 287void smp_setup_processor_id(void); 288 289int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, 290 bool phys); 291 292/* SMP core functions */ 293int smpcfd_prepare_cpu(unsigned int cpu); 294int smpcfd_dead_cpu(unsigned int cpu); 295int smpcfd_dying_cpu(unsigned int cpu); 296 297#endif /* __LINUX_SMP_H */ 298