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/smp_types.h>
  16
  17 typedef void (*smp_call_func_t)(void *info);
  18 typedef bool (*smp_cond_func_t)(int cpu, void *info);
  19
  20 /*
  21  * structure shares (partial) layout with struct irq_work
  22  */
  23 struct __call_single_data {
  24         struct __call_single_node node;
  25         smp_call_func_t func;
  26         void *info;
  27 };
  28
  29 #define CSD_INIT(_func, _info) \
  30         (struct __call_single_data){ .func = (_func), .info = (_info), }
  31
  32 /* Use __aligned() to avoid to use 2 cache lines for 1 csd */
  33 typedef struct __call_single_data call_single_data_t
  34         __aligned(sizeof(struct __call_single_data));
  35
  36 #define INIT_CSD(_csd, _func, _info)            \
  37 do {                                            \
  38         *(_csd) = CSD_INIT((_func), (_info));   \
  39 } while (0)
  40
  41 /*
  42  * Enqueue a llist_node on the call_single_queue; be very careful, read
  43  * flush_smp_call_function_queue() in detail.
  44  */
  45 extern void __smp_call_single_queue(int cpu, struct llist_node *node);
  46
  47 /* total number of cpus in this system (may exceed NR_CPUS) */
  48 extern unsigned int total_cpus;
  49
  50 int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
  51                              int wait);
  52
  53 void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
  54                            void *info, bool wait, const struct cpumask *mask);
  55
  56 int smp_call_function_single_async(int cpu, call_single_data_t *csd);
  57
  58 /*
  59  * Cpus stopping functions in panic. All have default weak definitions.
  60  * Architecture-dependent code may override them.
  61  */
  62 void __noreturn panic_smp_self_stop(void);
  63 void __noreturn nmi_panic_self_stop(struct pt_regs *regs);
  64 void crash_smp_send_stop(void);
  65
  66 /*
  67  * Call a function on all processors
  68  */
  69 static inline void on_each_cpu(smp_call_func_t func, void *info, int wait)
  70 {
  71         on_each_cpu_cond_mask(NULL, func, info, wait, cpu_online_mask);
  72 }
  73
  74 /**
  75  * on_each_cpu_mask(): Run a function on processors specified by
  76  * cpumask, which may include the local processor.
  77  * @mask: The set of cpus to run on (only runs on online subset).
  78  * @func: The function to run. This must be fast and non-blocking.
  79  * @info: An arbitrary pointer to pass to the function.
  80  * @wait: If true, wait (atomically) until function has completed
  81  *        on other CPUs.
  82  *
  83  * If @wait is true, then returns once @func has returned.
  84  *
  85  * You must not call this function with disabled interrupts or from a
  86  * hardware interrupt handler or from a bottom half handler.  The
  87  * exception is that it may be used during early boot while
  88  * early_boot_irqs_disabled is set.
  89  */
  90 static inline void on_each_cpu_mask(const struct cpumask *mask,
  91                                     smp_call_func_t func, void *info, bool wait)
  92 {
  93         on_each_cpu_cond_mask(NULL, func, info, wait, mask);
  94 }
  95
  96 /*
  97  * Call a function on each processor for which the supplied function
  98  * cond_func returns a positive value. This may include the local
  99  * processor.  May be used during early boot while early_boot_irqs_disabled is
 100  * set. Use local_irq_save/restore() instead of local_irq_disable/enable().
 101  */
 102 static inline void on_each_cpu_cond(smp_cond_func_t cond_func,
 103                                     smp_call_func_t func, void *info, bool wait)
 104 {
 105         on_each_cpu_cond_mask(cond_func, func, info, wait, cpu_online_mask);
 106 }
 107
 108 /*
 109  * Architecture specific boot CPU setup.  Defined as empty weak function in
 110  * init/main.c. Architectures can override it.
 111  */
 112 void __init smp_prepare_boot_cpu(void);
 113
 114 #ifdef CONFIG_SMP
 115
 116 #include <linux/preempt.h>
 117 #include <linux/compiler.h>
 118 #include <linux/thread_info.h>
 119 #include <asm/smp.h>
 120
 121 /*
 122  * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
 123  * (defined in asm header):
 124  */
 125
 126 /*
 127  * stops all CPUs but the current one:
 128  */
 129 extern void smp_send_stop(void);
 130
 131 /*
 132  * sends a 'reschedule' event to another CPU:
 133  */
 134 extern void arch_smp_send_reschedule(int cpu);
 135 /*
 136  * scheduler_ipi() is inline so can't be passed as callback reason, but the
 137  * callsite IP should be sufficient for root-causing IPIs sent from here.
 138  */
 139 #define smp_send_reschedule(cpu) ({               \
 140         trace_ipi_send_cpu(cpu, _RET_IP_, NULL);  \
 141         arch_smp_send_reschedule(cpu);            \
 142 })
 143
 144 /*
 145  * Prepare machine for booting other CPUs.
 146  */
 147 extern void smp_prepare_cpus(unsigned int max_cpus);
 148
 149 /*
 150  * Bring a CPU up
 151  */
 152 extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
 153
 154 /*
 155  * Final polishing of CPUs
 156  */
 157 extern void smp_cpus_done(unsigned int max_cpus);
 158
 159 /*
 160  * Call a function on all other processors
 161  */
 162 void smp_call_function(smp_call_func_t func, void *info, int wait);
 163 void smp_call_function_many(const struct cpumask *mask,
 164                             smp_call_func_t func, void *info, bool wait);
 165
 166 int smp_call_function_any(const struct cpumask *mask,
 167                           smp_call_func_t func, void *info, int wait);
 168
 169 void kick_all_cpus_sync(void);
 170 void wake_up_all_idle_cpus(void);
 171
 172 /*
 173  * Generic and arch helpers
 174  */
 175 void __init call_function_init(void);
 176 void generic_smp_call_function_single_interrupt(void);
 177 #define generic_smp_call_function_interrupt \
 178         generic_smp_call_function_single_interrupt
 179
 180 extern unsigned int setup_max_cpus;
 181 extern void __init setup_nr_cpu_ids(void);
 182 extern void __init smp_init(void);
 183
 184 extern int __boot_cpu_id;
 185
 186 static inline int get_boot_cpu_id(void)
 187 {
 188         return __boot_cpu_id;
 189 }
 190
 191 #else /* !SMP */
 192
 193 static inline void smp_send_stop(void) { }
 194
 195 /*
 196  *      These macros fold the SMP functionality into a single CPU system
 197  */
 198 #define raw_smp_processor_id()                  0
 199 static inline void up_smp_call_function(smp_call_func_t func, void *info)
 200 {
 201 }
 202 #define smp_call_function(func, info, wait) \
 203                         (up_smp_call_function(func, info))
 204
 205 static inline void smp_send_reschedule(int cpu) { }
 206 #define smp_call_function_many(mask, func, info, wait) \
 207                         (up_smp_call_function(func, info))
 208 static inline void call_function_init(void) { }
 209
 210 static inline int
 211 smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
 212                       void *info, int wait)
 213 {
 214         return smp_call_function_single(0, func, info, wait);
 215 }
 216
 217 static inline void kick_all_cpus_sync(void) {  }
 218 static inline void wake_up_all_idle_cpus(void) {  }
 219
 220 #define setup_max_cpus 0
 221
 222 #ifdef CONFIG_UP_LATE_INIT
 223 extern void __init up_late_init(void);
 224 static inline void smp_init(void) { up_late_init(); }
 225 #else
 226 static inline void smp_init(void) { }
 227 #endif
 228
 229 static inline int get_boot_cpu_id(void)
 230 {
 231         return 0;
 232 }
 233
 234 #endif /* !SMP */
 235
 236 /**
 237  * raw_processor_id() - get the current (unstable) CPU id
 238  *
 239  * For then you know what you are doing and need an unstable
 240  * CPU id.
 241  */
 242
 243 /**
 244  * smp_processor_id() - get the current (stable) CPU id
 245  *
 246  * This is the normal accessor to the CPU id and should be used
 247  * whenever possible.
 248  *
 249  * The CPU id is stable when:
 250  *
 251  *  - IRQs are disabled;
 252  *  - preemption is disabled;
 253  *  - the task is CPU affine.
 254  *
 255  * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN
 256  * when smp_processor_id() is used when the CPU id is not stable.
 257  */
 258
 259 /*
 260  * Allow the architecture to differentiate between a stable and unstable read.
 261  * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a
 262  * regular asm read for the stable.
 263  */
 264 #ifndef __smp_processor_id
 265 #define __smp_processor_id() raw_smp_processor_id()
 266 #endif
 267
 268 #ifdef CONFIG_DEBUG_PREEMPT
 269   extern unsigned int debug_smp_processor_id(void);
 270 # define smp_processor_id() debug_smp_processor_id()
 271 #else
 272 # define smp_processor_id() __smp_processor_id()
 273 #endif
 274
 275 #define get_cpu()               ({ preempt_disable(); __smp_processor_id(); })
 276 #define put_cpu()               preempt_enable()
 277
 278 /*
 279  * Callback to arch code if there's nosmp or maxcpus=0 on the
 280  * boot command line:
 281  */
 282 extern void arch_disable_smp_support(void);
 283
 284 extern void arch_thaw_secondary_cpus_begin(void);
 285 extern void arch_thaw_secondary_cpus_end(void);
 286
 287 void smp_setup_processor_id(void);
 288
 289 int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par,
 290                     bool phys);
 291
 292 /* SMP core functions */
 293 int smpcfd_prepare_cpu(unsigned int cpu);
 294 int smpcfd_dead_cpu(unsigned int cpu);
 295 int smpcfd_dying_cpu(unsigned int cpu);
 296
 297 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
 298 bool csd_lock_is_stuck(void);
 299 #else
 300 static inline bool csd_lock_is_stuck(void) { return false; }
 301 #endif
 302
 303 #endif /* __LINUX_SMP_H */