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