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