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/llist.h>
  16
  17 typedef void (*smp_call_func_t)(void *info);
  18 typedef bool (*smp_cond_func_t)(int cpu, void *info);
  19
  20 enum {
  21         CSD_FLAG_LOCK           = 0x01,
  22
  23         /* IRQ_WORK_flags */
  24
  25         CSD_TYPE_ASYNC          = 0x00,
  26         CSD_TYPE_SYNC           = 0x10,
  27         CSD_TYPE_IRQ_WORK       = 0x20,
  28         CSD_TYPE_TTWU           = 0x30,
  29         CSD_FLAG_TYPE_MASK      = 0xF0,
  30 };
  31
  32 /*
  33  * structure shares (partial) layout with struct irq_work
  34  */
  35 struct __call_single_data {
  36         struct llist_node llist;
  37         unsigned int flags;
  38         smp_call_func_t func;
  39         void *info;
  40 };
  41
  42 /* Use __aligned() to avoid to use 2 cache lines for 1 csd */
  43 typedef struct __call_single_data call_single_data_t
  44         __aligned(sizeof(struct __call_single_data));
  45
  46 /*
  47  * Enqueue a llist_node on the call_single_queue; be very careful, read
  48  * flush_smp_call_function_queue() in detail.
  49  */
  50 extern void __smp_call_single_queue(int cpu, struct llist_node *node);
  51
  52 /* total number of cpus in this system (may exceed NR_CPUS) */
  53 extern unsigned int total_cpus;
  54
  55 int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
  56                              int wait);
  57
  58 /*
  59  * Call a function on all processors
  60  */
  61 void on_each_cpu(smp_call_func_t func, void *info, int wait);
  62
  63 /*
  64  * Call a function on processors specified by mask, which might include
  65  * the local one.
  66  */
  67 void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
  68                 void *info, bool wait);
  69
  70 /*
  71  * Call a function on each processor for which the supplied function
  72  * cond_func returns a positive value. This may include the local
  73  * processor.
  74  */
  75 void on_each_cpu_cond(smp_cond_func_t cond_func, smp_call_func_t func,
  76                       void *info, bool wait);
  77
  78 void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
  79                            void *info, bool wait, const struct cpumask *mask);
  80
  81 int smp_call_function_single_async(int cpu, call_single_data_t *csd);
  82
  83 #ifdef CONFIG_SMP
  84
  85 #include <linux/preempt.h>
  86 #include <linux/kernel.h>
  87 #include <linux/compiler.h>
  88 #include <linux/thread_info.h>
  89 #include <asm/smp.h>
  90
  91 /*
  92  * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
  93  * (defined in asm header):
  94  */
  95
  96 /*
  97  * stops all CPUs but the current one:
  98  */
  99 extern void smp_send_stop(void);
 100
 101 /*
 102  * sends a 'reschedule' event to another CPU:
 103  */
 104 extern void smp_send_reschedule(int cpu);
 105
 106
 107 /*
 108  * Prepare machine for booting other CPUs.
 109  */
 110 extern void smp_prepare_cpus(unsigned int max_cpus);
 111
 112 /*
 113  * Bring a CPU up
 114  */
 115 extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
 116
 117 /*
 118  * Final polishing of CPUs
 119  */
 120 extern void smp_cpus_done(unsigned int max_cpus);
 121
 122 /*
 123  * Call a function on all other processors
 124  */
 125 void smp_call_function(smp_call_func_t func, void *info, int wait);
 126 void smp_call_function_many(const struct cpumask *mask,
 127                             smp_call_func_t func, void *info, bool wait);
 128
 129 int smp_call_function_any(const struct cpumask *mask,
 130                           smp_call_func_t func, void *info, int wait);
 131
 132 void kick_all_cpus_sync(void);
 133 void wake_up_all_idle_cpus(void);
 134
 135 /*
 136  * Generic and arch helpers
 137  */
 138 void __init call_function_init(void);
 139 void generic_smp_call_function_single_interrupt(void);
 140 #define generic_smp_call_function_interrupt \
 141         generic_smp_call_function_single_interrupt
 142
 143 /*
 144  * Mark the boot cpu "online" so that it can call console drivers in
 145  * printk() and can access its per-cpu storage.
 146  */
 147 void smp_prepare_boot_cpu(void);
 148
 149 extern unsigned int setup_max_cpus;
 150 extern void __init setup_nr_cpu_ids(void);
 151 extern void __init smp_init(void);
 152
 153 extern int __boot_cpu_id;
 154
 155 static inline int get_boot_cpu_id(void)
 156 {
 157         return __boot_cpu_id;
 158 }
 159
 160 #else /* !SMP */
 161
 162 static inline void smp_send_stop(void) { }
 163
 164 /*
 165  *      These macros fold the SMP functionality into a single CPU system
 166  */
 167 #define raw_smp_processor_id()                  0
 168 static inline void up_smp_call_function(smp_call_func_t func, void *info)
 169 {
 170 }
 171 #define smp_call_function(func, info, wait) \
 172                         (up_smp_call_function(func, info))
 173
 174 static inline void smp_send_reschedule(int cpu) { }
 175 #define smp_prepare_boot_cpu()                  do {} while (0)
 176 #define smp_call_function_many(mask, func, info, wait) \
 177                         (up_smp_call_function(func, info))
 178 static inline void call_function_init(void) { }
 179
 180 static inline int
 181 smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
 182                       void *info, int wait)
 183 {
 184         return smp_call_function_single(0, func, info, wait);
 185 }
 186
 187 static inline void kick_all_cpus_sync(void) {  }
 188 static inline void wake_up_all_idle_cpus(void) {  }
 189
 190 #ifdef CONFIG_UP_LATE_INIT
 191 extern void __init up_late_init(void);
 192 static inline void smp_init(void) { up_late_init(); }
 193 #else
 194 static inline void smp_init(void) { }
 195 #endif
 196
 197 static inline int get_boot_cpu_id(void)
 198 {
 199         return 0;
 200 }
 201
 202 #endif /* !SMP */
 203
 204 /**
 205  * raw_processor_id() - get the current (unstable) CPU id
 206  *
 207  * For then you know what you are doing and need an unstable
 208  * CPU id.
 209  */
 210
 211 /**
 212  * smp_processor_id() - get the current (stable) CPU id
 213  *
 214  * This is the normal accessor to the CPU id and should be used
 215  * whenever possible.
 216  *
 217  * The CPU id is stable when:
 218  *
 219  *  - IRQs are disabled;
 220  *  - preemption is disabled;
 221  *  - the task is CPU affine.
 222  *
 223  * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN
 224  * when smp_processor_id() is used when the CPU id is not stable.
 225  */
 226
 227 /*
 228  * Allow the architecture to differentiate between a stable and unstable read.
 229  * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a
 230  * regular asm read for the stable.
 231  */
 232 #ifndef __smp_processor_id
 233 #define __smp_processor_id(x) raw_smp_processor_id(x)
 234 #endif
 235
 236 #ifdef CONFIG_DEBUG_PREEMPT
 237   extern unsigned int debug_smp_processor_id(void);
 238 # define smp_processor_id() debug_smp_processor_id()
 239 #else
 240 # define smp_processor_id() __smp_processor_id()
 241 #endif
 242
 243 #define get_cpu()               ({ preempt_disable(); __smp_processor_id(); })
 244 #define put_cpu()               preempt_enable()
 245
 246 /*
 247  * Callback to arch code if there's nosmp or maxcpus=0 on the
 248  * boot command line:
 249  */
 250 extern void arch_disable_smp_support(void);
 251
 252 extern void arch_thaw_secondary_cpus_begin(void);
 253 extern void arch_thaw_secondary_cpus_end(void);
 254
 255 void smp_setup_processor_id(void);
 256
 257 int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par,
 258                     bool phys);
 259
 260 /* SMP core functions */
 261 int smpcfd_prepare_cpu(unsigned int cpu);
 262 int smpcfd_dead_cpu(unsigned int cpu);
 263 int smpcfd_dying_cpu(unsigned int cpu);
 264
 265 #endif /* __LINUX_SMP_H */