include/linux/smp.h

   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
  15 extern void cpu_idle(void);
  16
  17 typedef void (*smp_call_func_t)(void *info);
  18 struct 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) */
  27 extern unsigned int total_cpus;
  28
  29 int 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  */
  48 extern void smp_send_stop(void);
  49
  50 /*
  51  * sends a 'reschedule' event to another CPU:
  52  */
  53 extern void smp_send_reschedule(int cpu);
  54
  55
  56 /*
  57  * Prepare machine for booting other CPUs.
  58  */
  59 extern void smp_prepare_cpus(unsigned int max_cpus);
  60
  61 /*
  62  * Bring a CPU up
  63  */
  64 extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
  65
  66 /*
  67  * Final polishing of CPUs
  68  */
  69 extern void smp_cpus_done(unsigned int max_cpus);
  70
  71 /*
  72  * Call a function on all other processors
  73  */
  74 int smp_call_function(smp_call_func_t func, void *info, int wait);
  75 void smp_call_function_many(const struct cpumask *mask,
  76                             smp_call_func_t func, void *info, bool wait);
  77
  78 void __smp_call_function_single(int cpuid, struct call_single_data *data,
  79                                 int wait);
  80
  81 int smp_call_function_any(const struct cpumask *mask,
  82                           smp_call_func_t func, void *info, int wait);
  83
  84 void kick_all_cpus_sync(void);
  85
  86 /*
  87  * Generic and arch helpers
  88  */
  89 #ifdef CONFIG_USE_GENERIC_SMP_HELPERS
  90 void __init call_function_init(void);
  91 void generic_smp_call_function_single_interrupt(void);
  92 void generic_smp_call_function_interrupt(void);
  93 #else
  94 static inline void call_function_init(void) { }
  95 #endif
  96
  97 /*
  98  * Call a function on all processors
  99  */
 100 int 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  */
 106 void 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  */
 114 void 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  */
 122 void smp_prepare_boot_cpu(void);
 123
 124 extern unsigned int setup_max_cpus;
 125 extern void __init setup_nr_cpu_ids(void);
 126 extern void __init smp_init(void);
 127
 128 #else /* !SMP */
 129
 130 static 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
 136 static 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
 179 static 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))
 183 static inline void call_function_init(void) { }
 184
 185 static inline int
 186 smp_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
 192 static 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  */
 225 extern void arch_disable_smp_support(void);
 226
 227 void smp_setup_processor_id(void);
 228
 229 #endif /* __LINUX_SMP_H */