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/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 /*
  54  * Call a function on all processors
  55  */
  56 void on_each_cpu(smp_call_func_t func, void *info, int wait);
  57
  58 /*
  59  * Call a function on processors specified by mask, which might include
  60  * the local one.
  61  */
  62 void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
  63                 void *info, bool wait);
  64
  65 /*
  66  * Call a function on each processor for which the supplied function
  67  * cond_func returns a positive value. This may include the local
  68  * processor.
  69  */
  70 void on_each_cpu_cond(smp_cond_func_t cond_func, smp_call_func_t func,
  71                       void *info, bool wait);
  72
  73 void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
  74                            void *info, bool wait, const struct cpumask *mask);
  75
  76 int smp_call_function_single_async(int cpu, struct __call_single_data *csd);
  77
  78 #ifdef CONFIG_SMP
  79
  80 #include <linux/preempt.h>
  81 #include <linux/kernel.h>
  82 #include <linux/compiler.h>
  83 #include <linux/thread_info.h>
  84 #include <asm/smp.h>
  85
  86 /*
  87  * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
  88  * (defined in asm header):
  89  */
  90
  91 /*
  92  * stops all CPUs but the current one:
  93  */
  94 extern void smp_send_stop(void);
  95
  96 /*
  97  * sends a 'reschedule' event to another CPU:
  98  */
  99 extern void smp_send_reschedule(int cpu);
 100
 101
 102 /*
 103  * Prepare machine for booting other CPUs.
 104  */
 105 extern void smp_prepare_cpus(unsigned int max_cpus);
 106
 107 /*
 108  * Bring a CPU up
 109  */
 110 extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
 111
 112 /*
 113  * Final polishing of CPUs
 114  */
 115 extern void smp_cpus_done(unsigned int max_cpus);
 116
 117 /*
 118  * Call a function on all other processors
 119  */
 120 void smp_call_function(smp_call_func_t func, void *info, int wait);
 121 void smp_call_function_many(const struct cpumask *mask,
 122                             smp_call_func_t func, void *info, bool wait);
 123
 124 int smp_call_function_any(const struct cpumask *mask,
 125                           smp_call_func_t func, void *info, int wait);
 126
 127 void kick_all_cpus_sync(void);
 128 void wake_up_all_idle_cpus(void);
 129
 130 /*
 131  * Generic and arch helpers
 132  */
 133 void __init call_function_init(void);
 134 void generic_smp_call_function_single_interrupt(void);
 135 #define generic_smp_call_function_interrupt \
 136         generic_smp_call_function_single_interrupt
 137
 138 /*
 139  * Mark the boot cpu "online" so that it can call console drivers in
 140  * printk() and can access its per-cpu storage.
 141  */
 142 void smp_prepare_boot_cpu(void);
 143
 144 extern unsigned int setup_max_cpus;
 145 extern void __init setup_nr_cpu_ids(void);
 146 extern void __init smp_init(void);
 147
 148 extern int __boot_cpu_id;
 149
 150 static inline int get_boot_cpu_id(void)
 151 {
 152         return __boot_cpu_id;
 153 }
 154
 155 #else /* !SMP */
 156
 157 static inline void smp_send_stop(void) { }
 158
 159 /*
 160  *      These macros fold the SMP functionality into a single CPU system
 161  */
 162 #define raw_smp_processor_id()                  0
 163 static inline void up_smp_call_function(smp_call_func_t func, void *info)
 164 {
 165 }
 166 #define smp_call_function(func, info, wait) \
 167                         (up_smp_call_function(func, info))
 168
 169 static inline void smp_send_reschedule(int cpu) { }
 170 #define smp_prepare_boot_cpu()                  do {} while (0)
 171 #define smp_call_function_many(mask, func, info, wait) \
 172                         (up_smp_call_function(func, info))
 173 static inline void call_function_init(void) { }
 174
 175 static inline int
 176 smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
 177                       void *info, int wait)
 178 {
 179         return smp_call_function_single(0, func, info, wait);
 180 }
 181
 182 static inline void kick_all_cpus_sync(void) {  }
 183 static inline void wake_up_all_idle_cpus(void) {  }
 184
 185 #ifdef CONFIG_UP_LATE_INIT
 186 extern void __init up_late_init(void);
 187 static inline void smp_init(void) { up_late_init(); }
 188 #else
 189 static inline void smp_init(void) { }
 190 #endif
 191
 192 static inline int get_boot_cpu_id(void)
 193 {
 194         return 0;
 195 }
 196
 197 #endif /* !SMP */
 198
 199 /**
 200  * raw_processor_id() - get the current (unstable) CPU id
 201  *
 202  * For then you know what you are doing and need an unstable
 203  * CPU id.
 204  */
 205
 206 /**
 207  * smp_processor_id() - get the current (stable) CPU id
 208  *
 209  * This is the normal accessor to the CPU id and should be used
 210  * whenever possible.
 211  *
 212  * The CPU id is stable when:
 213  *
 214  *  - IRQs are disabled;
 215  *  - preemption is disabled;
 216  *  - the task is CPU affine.
 217  *
 218  * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN
 219  * when smp_processor_id() is used when the CPU id is not stable.
 220  */
 221
 222 /*
 223  * Allow the architecture to differentiate between a stable and unstable read.
 224  * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a
 225  * regular asm read for the stable.
 226  */
 227 #ifndef __smp_processor_id
 228 #define __smp_processor_id(x) raw_smp_processor_id(x)
 229 #endif
 230
 231 #ifdef CONFIG_DEBUG_PREEMPT
 232   extern unsigned int debug_smp_processor_id(void);
 233 # define smp_processor_id() debug_smp_processor_id()
 234 #else
 235 # define smp_processor_id() __smp_processor_id()
 236 #endif
 237
 238 #define get_cpu()               ({ preempt_disable(); __smp_processor_id(); })
 239 #define put_cpu()               preempt_enable()
 240
 241 /*
 242  * Callback to arch code if there's nosmp or maxcpus=0 on the
 243  * boot command line:
 244  */
 245 extern void arch_disable_smp_support(void);
 246
 247 extern void arch_thaw_secondary_cpus_begin(void);
 248 extern void arch_thaw_secondary_cpus_end(void);
 249
 250 void smp_setup_processor_id(void);
 251
 252 int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par,
 253                     bool phys);
 254
 255 /* SMP core functions */
 256 int smpcfd_prepare_cpu(unsigned int cpu);
 257 int smpcfd_dead_cpu(unsigned int cpu);
 258 int smpcfd_dying_cpu(unsigned int cpu);
 259
 260 #endif /* __LINUX_SMP_H */