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);
  92void generic_smp_call_function_interrupt(void);
  93#else
  94static inline void call_function_init(void) { }
  95#endif
  96
  97/*
  98 * Call a function on all processors
  99 */
 100int on_each_cpu(smp_call_func_t func, void *info, int wait);
 101
 102/*
 103 * Call a function on processors specified by mask, which might include
 104 * the local one.
 105 */
 106void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
 107                void *info, bool wait);
 108
 109/*
 110 * Call a function on each processor for which the supplied function
 111 * cond_func returns a positive value. This may include the local
 112 * processor.
 113 */
 114void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
 115                smp_call_func_t func, void *info, bool wait,
 116                gfp_t gfp_flags);
 117
 118/*
 119 * Mark the boot cpu "online" so that it can call console drivers in
 120 * printk() and can access its per-cpu storage.
 121 */
 122void smp_prepare_boot_cpu(void);
 123
 124extern unsigned int setup_max_cpus;
 125extern void __init setup_nr_cpu_ids(void);
 126extern void __init smp_init(void);
 127
 128#else /* !SMP */
 129
 130static inline void smp_send_stop(void) { }
 131
 132/*
 133 *      These macros fold the SMP functionality into a single CPU system
 134 */
 135#define raw_smp_processor_id()                  0
 136static inline int up_smp_call_function(smp_call_func_t func, void *info)
 137{
 138        return 0;
 139}
 140#define smp_call_function(func, info, wait) \
 141                        (up_smp_call_function(func, info))
 142#define on_each_cpu(func,info,wait)             \
 143        ({                                      \
 144                local_irq_disable();            \
 145                func(info);                     \
 146                local_irq_enable();             \
 147                0;                              \
 148        })
 149/*
 150 * Note we still need to test the mask even for UP
 151 * because we actually can get an empty mask from
 152 * code that on SMP might call us without the local
 153 * CPU in the mask.
 154 */
 155#define on_each_cpu_mask(mask, func, info, wait) \
 156        do {                                            \
 157                if (cpumask_test_cpu(0, (mask))) {      \
 158                        local_irq_disable();            \
 159                        (func)(info);                   \
 160                        local_irq_enable();             \
 161                }                                       \
 162        } while (0)
 163/*
 164 * Preemption is disabled here to make sure the cond_func is called under the
 165 * same condtions in UP and SMP.
 166 */
 167#define on_each_cpu_cond(cond_func, func, info, wait, gfp_flags)\
 168        do {                                                    \
 169                void *__info = (info);                          \
 170                preempt_disable();                              \
 171                if ((cond_func)(0, __info)) {                   \
 172                        local_irq_disable();                    \
 173                        (func)(__info);                         \
 174                        local_irq_enable();                     \
 175                }                                               \
 176                preempt_enable();                               \
 177        } while (0)
 178
 179static inline void smp_send_reschedule(int cpu) { }
 180#define smp_prepare_boot_cpu()                  do {} while (0)
 181#define smp_call_function_many(mask, func, info, wait) \
 182                        (up_smp_call_function(func, info))
 183static inline void call_function_init(void) { }
 184
 185static inline int
 186smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
 187                      void *info, int wait)
 188{
 189        return smp_call_function_single(0, func, info, wait);
 190}
 191
 192static inline void kick_all_cpus_sync(void) {  }
 193
 194#endif /* !SMP */
 195
 196/*
 197 * smp_processor_id(): get the current CPU ID.
 198 *
 199 * if DEBUG_PREEMPT is enabled then we check whether it is
 200 * used in a preemption-safe way. (smp_processor_id() is safe
 201 * if it's used in a preemption-off critical section, or in
 202 * a thread that is bound to the current CPU.)
 203 *
 204 * NOTE: raw_smp_processor_id() is for internal use only
 205 * (smp_processor_id() is the preferred variant), but in rare
 206 * instances it might also be used to turn off false positives
 207 * (i.e. smp_processor_id() use that the debugging code reports but
 208 * which use for some reason is legal). Don't use this to hack around
 209 * the warning message, as your code might not work under PREEMPT.
 210 */
 211#ifdef CONFIG_DEBUG_PREEMPT
 212  extern unsigned int debug_smp_processor_id(void);
 213# define smp_processor_id() debug_smp_processor_id()
 214#else
 215# define smp_processor_id() raw_smp_processor_id()
 216#endif
 217
 218#define get_cpu()               ({ preempt_disable(); smp_processor_id(); })
 219#define put_cpu()               preempt_enable()
 220
 221/*
 222 * Callback to arch code if there's nosmp or maxcpus=0 on the
 223 * boot command line:
 224 */
 225extern void arch_disable_smp_support(void);
 226
 227void smp_setup_processor_id(void);
 228
 229#endif /* __LINUX_SMP_H */
 230
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