include/linux/smp.h

   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/llist.h>
  16
  17 typedef void (*smp_call_func_t)(void *info);
  18 typedef bool (*smp_cond_func_t)(int cpu, void *info);
  19 struct __call_single_data {
  20         struct llist_node llist;
  21         smp_call_func_t func;
  22         void *info;
  23         unsigned int flags;
  24 };
  25
  26 /* Use __aligned() to avoid to use 2 cache lines for 1 csd */
  27 typedef struct __call_single_data call_single_data_t
  28         __aligned(sizeof(struct __call_single_data));
  29
  30 /* total number of cpus in this system (may exceed NR_CPUS) */
  31 extern unsigned int total_cpus;
  32
  33 int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
  34                              int wait);
  35
  36 /*
  37  * Call a function on all processors
  38  */
  39 void on_each_cpu(smp_call_func_t func, void *info, int wait);
  40
  41 /*
  42  * Call a function on processors specified by mask, which might include
  43  * the local one.
  44  */
  45 void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
  46                 void *info, bool wait);
  47
  48 /*
  49  * Call a function on each processor for which the supplied function
  50  * cond_func returns a positive value. This may include the local
  51  * processor.
  52  */
  53 void on_each_cpu_cond(smp_cond_func_t cond_func, smp_call_func_t func,
  54                       void *info, bool wait);
  55
  56 void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
  57                            void *info, bool wait, const struct cpumask *mask);
  58
  59 int smp_call_function_single_async(int cpu, call_single_data_t *csd);
  60
  61 #ifdef CONFIG_SMP
  62
  63 #include <linux/preempt.h>
  64 #include <linux/kernel.h>
  65 #include <linux/compiler.h>
  66 #include <linux/thread_info.h>
  67 #include <asm/smp.h>
  68
  69 /*
  70  * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
  71  * (defined in asm header):
  72  */
  73
  74 /*
  75  * stops all CPUs but the current one:
  76  */
  77 extern void smp_send_stop(void);
  78
  79 /*
  80  * sends a 'reschedule' event to another CPU:
  81  */
  82 extern void smp_send_reschedule(int cpu);
  83
  84
  85 /*
  86  * Prepare machine for booting other CPUs.
  87  */
  88 extern void smp_prepare_cpus(unsigned int max_cpus);
  89
  90 /*
  91  * Bring a CPU up
  92  */
  93 extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
  94
  95 /*
  96  * Final polishing of CPUs
  97  */
  98 extern void smp_cpus_done(unsigned int max_cpus);
  99
 100 /*
 101  * Call a function on all other processors
 102  */
 103 void smp_call_function(smp_call_func_t func, void *info, int wait);
 104 void smp_call_function_many(const struct cpumask *mask,
 105                             smp_call_func_t func, void *info, bool wait);
 106
 107 int smp_call_function_any(const struct cpumask *mask,
 108                           smp_call_func_t func, void *info, int wait);
 109
 110 void kick_all_cpus_sync(void);
 111 void wake_up_all_idle_cpus(void);
 112
 113 /*
 114  * Generic and arch helpers
 115  */
 116 void __init call_function_init(void);
 117 void generic_smp_call_function_single_interrupt(void);
 118 #define generic_smp_call_function_interrupt \
 119         generic_smp_call_function_single_interrupt
 120
 121 /*
 122  * Mark the boot cpu "online" so that it can call console drivers in
 123  * printk() and can access its per-cpu storage.
 124  */
 125 void smp_prepare_boot_cpu(void);
 126
 127 extern unsigned int setup_max_cpus;
 128 extern void __init setup_nr_cpu_ids(void);
 129 extern void __init smp_init(void);
 130
 131 extern int __boot_cpu_id;
 132
 133 static inline int get_boot_cpu_id(void)
 134 {
 135         return __boot_cpu_id;
 136 }
 137
 138 #else /* !SMP */
 139
 140 static inline void smp_send_stop(void) { }
 141
 142 /*
 143  *      These macros fold the SMP functionality into a single CPU system
 144  */
 145 #define raw_smp_processor_id()                  0
 146 static inline void up_smp_call_function(smp_call_func_t func, void *info)
 147 {
 148 }
 149 #define smp_call_function(func, info, wait) \
 150                         (up_smp_call_function(func, info))
 151
 152 static inline void smp_send_reschedule(int cpu) { }
 153 #define smp_prepare_boot_cpu()                  do {} while (0)
 154 #define smp_call_function_many(mask, func, info, wait) \
 155                         (up_smp_call_function(func, info))
 156 static inline void call_function_init(void) { }
 157
 158 static inline int
 159 smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
 160                       void *info, int wait)
 161 {
 162         return smp_call_function_single(0, func, info, wait);
 163 }
 164
 165 static inline void kick_all_cpus_sync(void) {  }
 166 static inline void wake_up_all_idle_cpus(void) {  }
 167
 168 #ifdef CONFIG_UP_LATE_INIT
 169 extern void __init up_late_init(void);
 170 static inline void smp_init(void) { up_late_init(); }
 171 #else
 172 static inline void smp_init(void) { }
 173 #endif
 174
 175 static inline int get_boot_cpu_id(void)
 176 {
 177         return 0;
 178 }
 179
 180 #endif /* !SMP */
 181
 182 /**
 183  * raw_processor_id() - get the current (unstable) CPU id
 184  *
 185  * For then you know what you are doing and need an unstable
 186  * CPU id.
 187  */
 188
 189 /**
 190  * smp_processor_id() - get the current (stable) CPU id
 191  *
 192  * This is the normal accessor to the CPU id and should be used
 193  * whenever possible.
 194  *
 195  * The CPU id is stable when:
 196  *
 197  *  - IRQs are disabled;
 198  *  - preemption is disabled;
 199  *  - the task is CPU affine.
 200  *
 201  * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN
 202  * when smp_processor_id() is used when the CPU id is not stable.
 203  */
 204
 205 /*
 206  * Allow the architecture to differentiate between a stable and unstable read.
 207  * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a
 208  * regular asm read for the stable.
 209  */
 210 #ifndef __smp_processor_id
 211 #define __smp_processor_id(x) raw_smp_processor_id(x)
 212 #endif
 213
 214 #ifdef CONFIG_DEBUG_PREEMPT
 215   extern unsigned int debug_smp_processor_id(void);
 216 # define smp_processor_id() debug_smp_processor_id()
 217 #else
 218 # define smp_processor_id() __smp_processor_id()
 219 #endif
 220
 221 #define get_cpu()               ({ preempt_disable(); __smp_processor_id(); })
 222 #define put_cpu()               preempt_enable()
 223
 224 /*
 225  * Callback to arch code if there's nosmp or maxcpus=0 on the
 226  * boot command line:
 227  */
 228 extern void arch_disable_smp_support(void);
 229
 230 extern void arch_enable_nonboot_cpus_begin(void);
 231 extern void arch_enable_nonboot_cpus_end(void);
 232
 233 void smp_setup_processor_id(void);
 234
 235 int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par,
 236                     bool phys);
 237
 238 /* SMP core functions */
 239 int smpcfd_prepare_cpu(unsigned int cpu);
 240 int smpcfd_dead_cpu(unsigned int cpu);
 241 int smpcfd_dying_cpu(unsigned int cpu);
 242
 243 #endif /* __LINUX_SMP_H */