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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. <[email protected]>
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);
19  struct list_head list;
21  void *info;
24 };
25 
26 /* total number of cpus in this system (may exceed NR_CPUS) */
27 extern unsigned int total_cpus;
28 
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  */
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 */