LXR linux/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
  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        union {
  25                struct __call_single_node node;
  26                struct {
  27                        struct llist_node llist;
  28                        unsigned int flags;
  29#ifdef CONFIG_64BIT
  30                        u16 src, dst;
  31#endif
  32                };
  33        };
  34        smp_call_func_t func;
  35        void *info;
  36};
  37
  38/* Use __aligned() to avoid to use 2 cache lines for 1 csd */
  39typedef struct __call_single_data call_single_data_t
  40        __aligned(sizeof(struct __call_single_data));
  41
  42/*
  43 * Enqueue a llist_node on the call_single_queue; be very careful, read
  44 * flush_smp_call_function_queue() in detail.
  45 */
  46extern void __smp_call_single_queue(int cpu, struct llist_node *node);
  47
  48/* total number of cpus in this system (may exceed NR_CPUS) */
  49extern unsigned int total_cpus;
  50
  51int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
  52                             int wait);
  53
  54/*
  55 * Call a function on all processors
  56 */
  57void on_each_cpu(smp_call_func_t func, void *info, int wait);
  58
  59/*
  60 * Call a function on processors specified by mask, which might include
  61 * the local one.
  62 */
  63void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
  64                void *info, bool wait);
  65
  66/*
  67 * Call a function on each processor for which the supplied function
  68 * cond_func returns a positive value. This may include the local
  69 * processor.
  70 */
  71void on_each_cpu_cond(smp_cond_func_t cond_func, smp_call_func_t func,
  72                      void *info, bool wait);
  73
  74void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
  75                           void *info, bool wait, const struct cpumask *mask);
  76
  77int smp_call_function_single_async(int cpu, call_single_data_t *csd);
  78
  79#ifdef CONFIG_SMP
  80
  81#include <linux/preempt.h>
  82#include <linux/kernel.h>
  83#include <linux/compiler.h>
  84#include <linux/thread_info.h>
  85#include <asm/smp.h>
  86
  87/*
  88 * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
  89 * (defined in asm header):
  90 */
  91
  92/*
  93 * stops all CPUs but the current one:
  94 */
  95extern void smp_send_stop(void);
  96
  97/*
  98 * sends a 'reschedule' event to another CPU:
  99 */
 100extern void smp_send_reschedule(int cpu);
 101
 102
 103/*
 104 * Prepare machine for booting other CPUs.
 105 */
 106extern void smp_prepare_cpus(unsigned int max_cpus);
 107
 108/*
 109 * Bring a CPU up
 110 */
 111extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
 112
 113/*
 114 * Final polishing of CPUs
 115 */
 116extern void smp_cpus_done(unsigned int max_cpus);
 117
 118/*
 119 * Call a function on all other processors
 120 */
 121void smp_call_function(smp_call_func_t func, void *info, int wait);
 122void smp_call_function_many(const struct cpumask *mask,
 123                            smp_call_func_t func, void *info, bool wait);
 124
 125int smp_call_function_any(const struct cpumask *mask,
 126                          smp_call_func_t func, void *info, int wait);
 127
 128void kick_all_cpus_sync(void);
 129void wake_up_all_idle_cpus(void);
 130
 131/*
 132 * Generic and arch helpers
 133 */
 134void __init call_function_init(void);
 135void generic_smp_call_function_single_interrupt(void);
 136#define generic_smp_call_function_interrupt \
 137        generic_smp_call_function_single_interrupt
 138
 139/*
 140 * Mark the boot cpu "online" so that it can call console drivers in
 141 * printk() and can access its per-cpu storage.
 142 */
 143void smp_prepare_boot_cpu(void);
 144
 145extern unsigned int setup_max_cpus;
 146extern void __init setup_nr_cpu_ids(void);
 147extern void __init smp_init(void);
 148
 149extern int __boot_cpu_id;
 150
 151static inline int get_boot_cpu_id(void)
 152{
 153        return __boot_cpu_id;
 154}
 155
 156#else /* !SMP */
 157
 158static inline void smp_send_stop(void) { }
 159
 160/*
 161 *      These macros fold the SMP functionality into a single CPU system
 162 */
 163#define raw_smp_processor_id()                  0
 164static inline void up_smp_call_function(smp_call_func_t func, void *info)
 165{
 166}
 167#define smp_call_function(func, info, wait) \
 168                        (up_smp_call_function(func, info))
 169
 170static inline void smp_send_reschedule(int cpu) { }
 171#define smp_prepare_boot_cpu()                  do {} while (0)
 172#define smp_call_function_many(mask, func, info, wait) \
 173                        (up_smp_call_function(func, info))
 174static inline void call_function_init(void) { }
 175
 176static inline int
 177smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
 178                      void *info, int wait)
 179{
 180        return smp_call_function_single(0, func, info, wait);
 181}
 182
 183static inline void kick_all_cpus_sync(void) {  }
 184static inline void wake_up_all_idle_cpus(void) {  }
 185
 186#ifdef CONFIG_UP_LATE_INIT
 187extern void __init up_late_init(void);
 188static inline void smp_init(void) { up_late_init(); }
 189#else
 190static inline void smp_init(void) { }
 191#endif
 192
 193static inline int get_boot_cpu_id(void)
 194{
 195        return 0;
 196}
 197
 198#endif /* !SMP */
 199
 200/**
 201 * raw_processor_id() - get the current (unstable) CPU id
 202 *
 203 * For then you know what you are doing and need an unstable
 204 * CPU id.
 205 */
 206
 207/**
 208 * smp_processor_id() - get the current (stable) CPU id
 209 *
 210 * This is the normal accessor to the CPU id and should be used
 211 * whenever possible.
 212 *
 213 * The CPU id is stable when:
 214 *
 215 *  - IRQs are disabled;
 216 *  - preemption is disabled;
 217 *  - the task is CPU affine.
 218 *
 219 * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN
 220 * when smp_processor_id() is used when the CPU id is not stable.
 221 */
 222
 223/*
 224 * Allow the architecture to differentiate between a stable and unstable read.
 225 * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a
 226 * regular asm read for the stable.
 227 */
 228#ifndef __smp_processor_id
 229#define __smp_processor_id(x) raw_smp_processor_id(x)
 230#endif
 231
 232#ifdef CONFIG_DEBUG_PREEMPT
 233  extern unsigned int debug_smp_processor_id(void);
 234# define smp_processor_id() debug_smp_processor_id()
 235#else
 236# define smp_processor_id() __smp_processor_id()
 237#endif
 238
 239#define get_cpu()               ({ preempt_disable(); __smp_processor_id(); })
 240#define put_cpu()               preempt_enable()
 241
 242/*
 243 * Callback to arch code if there's nosmp or maxcpus=0 on the
 244 * boot command line:
 245 */
 246extern void arch_disable_smp_support(void);
 247
 248extern void arch_thaw_secondary_cpus_begin(void);
 249extern void arch_thaw_secondary_cpus_end(void);
 250
 251void smp_setup_processor_id(void);
 252
 253int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par,
 254                    bool phys);
 255
 256/* SMP core functions */
 257int smpcfd_prepare_cpu(unsigned int cpu);
 258int smpcfd_dead_cpu(unsigned int cpu);
 259int smpcfd_dying_cpu(unsigned int cpu);
 260
 261#endif /* __LINUX_SMP_H */
 262