linux/include/linux/smp.h
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   1#ifndef __LINUX_SMP_H
   2#define __LINUX_SMP_H
   3
   4/*
   5 *      Generic SMP support
   6 *              Alan Cox. <alan@redhat.com>
   7 */
   8
   9#include <linux/errno.h>
  10#include <linux/types.h>
  11#include <linux/list.h>
  12#include <linux/cpumask.h>
  13#include <linux/init.h>
  14
  15extern void cpu_idle(void);
  16
  17typedef void (*smp_call_func_t)(void *info);
  18struct call_single_data {
  19        struct list_head list;
  20        smp_call_func_t func;
  21        void *info;
  22        u16 flags;
  23        u16 priv;
  24};
  25
  26/* total number of cpus in this system (may exceed NR_CPUS) */
  27extern unsigned int total_cpus;
  28
  29int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
  30                             int wait);
  31
  32#ifdef CONFIG_SMP
  33
  34#include <linux/preempt.h>
  35#include <linux/kernel.h>
  36#include <linux/compiler.h>
  37#include <linux/thread_info.h>
  38#include <asm/smp.h>
  39
  40/*
  41 * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
  42 * (defined in asm header):
  43 */
  44
  45/*
  46 * stops all CPUs but the current one:
  47 */
  48extern void smp_send_stop(void);
  49
  50/*
  51 * sends a 'reschedule' event to another CPU:
  52 */
  53extern void smp_send_reschedule(int cpu);
  54
  55
  56/*
  57 * Prepare machine for booting other CPUs.
  58 */
  59extern void smp_prepare_cpus(unsigned int max_cpus);
  60
  61/*
  62 * Bring a CPU up
  63 */
  64extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
  65
  66/*
  67 * Final polishing of CPUs
  68 */
  69extern void smp_cpus_done(unsigned int max_cpus);
  70
  71/*
  72 * Call a function on all other processors
  73 */
  74int smp_call_function(smp_call_func_t func, void *info, int wait);
  75void smp_call_function_many(const struct cpumask *mask,
  76                            smp_call_func_t func, void *info, bool wait);
  77
  78void __smp_call_function_single(int cpuid, struct call_single_data *data,
  79                                int wait);
  80
  81int smp_call_function_any(const struct cpumask *mask,
  82                          smp_call_func_t func, void *info, int wait);
  83
  84void kick_all_cpus_sync(void);
  85
  86/*
  87 * Generic and arch helpers
  88 */
  89#ifdef CONFIG_USE_GENERIC_SMP_HELPERS
  90void __init call_function_init(void);
  91void generic_smp_call_function_single_interrupt(void);
  92#define generic_smp_call_function_interrupt \
  93        generic_smp_call_function_single_interrupt
  94#else
  95static inline void call_function_init(void) { }
  96#endif
  97
  98/*
  99 * Call a function on all processors
 100 */
 101int on_each_cpu(smp_call_func_t func, void *info, int wait);
 102
 103/*
 104 * Call a function on processors specified by mask, which might include
 105 * the local one.
 106 */
 107void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
 108                void *info, bool wait);
 109
 110/*
 111 * Call a function on each processor for which the supplied function
 112 * cond_func returns a positive value. This may include the local
 113 * processor.
 114 */
 115void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
 116                smp_call_func_t func, void *info, bool wait,
 117                gfp_t gfp_flags);
 118
 119/*
 120 * Mark the boot cpu "online" so that it can call console drivers in
 121 * printk() and can access its per-cpu storage.
 122 */
 123void smp_prepare_boot_cpu(void);
 124
 125extern unsigned int setup_max_cpus;
 126extern void __init setup_nr_cpu_ids(void);
 127extern void __init smp_init(void);
 128
 129#else /* !SMP */
 130
 131static inline void smp_send_stop(void) { }
 132
 133/*
 134 *      These macros fold the SMP functionality into a single CPU system
 135 */
 136#define raw_smp_processor_id()                  0
 137static inline int up_smp_call_function(smp_call_func_t func, void *info)
 138{
 139        return 0;
 140}
 141#define smp_call_function(func, info, wait) \
 142                        (up_smp_call_function(func, info))
 143#define on_each_cpu(func,info,wait)             \
 144        ({                                      \
 145                local_irq_disable();            \
 146                func(info);                     \
 147                local_irq_enable();             \
 148                0;                              \
 149        })
 150/*
 151 * Note we still need to test the mask even for UP
 152 * because we actually can get an empty mask from
 153 * code that on SMP might call us without the local
 154 * CPU in the mask.
 155 */
 156#define on_each_cpu_mask(mask, func, info, wait) \
 157        do {                                            \
 158                if (cpumask_test_cpu(0, (mask))) {      \
 159                        local_irq_disable();            \
 160                        (func)(info);                   \
 161                        local_irq_enable();             \
 162                }                                       \
 163        } while (0)
 164/*
 165 * Preemption is disabled here to make sure the cond_func is called under the
 166 * same condtions in UP and SMP.
 167 */
 168#define on_each_cpu_cond(cond_func, func, info, wait, gfp_flags)\
 169        do {                                                    \
 170                void *__info = (info);                          \
 171                preempt_disable();                              \
 172                if ((cond_func)(0, __info)) {                   \
 173                        local_irq_disable();                    \
 174                        (func)(__info);                         \
 175                        local_irq_enable();                     \
 176                }                                               \
 177                preempt_enable();                               \
 178        } while (0)
 179
 180static inline void smp_send_reschedule(int cpu) { }
 181#define smp_prepare_boot_cpu()                  do {} while (0)
 182#define smp_call_function_many(mask, func, info, wait) \
 183                        (up_smp_call_function(func, info))
 184static inline void call_function_init(void) { }
 185
 186static inline int
 187smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
 188                      void *info, int wait)
 189{
 190        return smp_call_function_single(0, func, info, wait);
 191}
 192
 193static inline void kick_all_cpus_sync(void) {  }
 194
 195#endif /* !SMP */
 196
 197/*
 198 * smp_processor_id(): get the current CPU ID.
 199 *
 200 * if DEBUG_PREEMPT is enabled then we check whether it is
 201 * used in a preemption-safe way. (smp_processor_id() is safe
 202 * if it's used in a preemption-off critical section, or in
 203 * a thread that is bound to the current CPU.)
 204 *
 205 * NOTE: raw_smp_processor_id() is for internal use only
 206 * (smp_processor_id() is the preferred variant), but in rare
 207 * instances it might also be used to turn off false positives
 208 * (i.e. smp_processor_id() use that the debugging code reports but
 209 * which use for some reason is legal). Don't use this to hack around
 210 * the warning message, as your code might not work under PREEMPT.
 211 */
 212#ifdef CONFIG_DEBUG_PREEMPT
 213  extern unsigned int debug_smp_processor_id(void);
 214# define smp_processor_id() debug_smp_processor_id()
 215#else
 216# define smp_processor_id() raw_smp_processor_id()
 217#endif
 218
 219#define get_cpu()               ({ preempt_disable(); smp_processor_id(); })
 220#define put_cpu()               preempt_enable()
 221
 222/*
 223 * Callback to arch code if there's nosmp or maxcpus=0 on the
 224 * boot command line:
 225 */
 226extern void arch_disable_smp_support(void);
 227
 228void smp_setup_processor_id(void);
 229
 230#endif /* __LINUX_SMP_H */
 231
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