include/linux/smp.h

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002 #ifndef __LINUX_SMP_H
0003 #define __LINUX_SMP_H
0004
0005 /*
0006  *  Generic SMP support
0007  *      Alan Cox. <alan@redhat.com>
0008  */
0009
0010 #include <linux/errno.h>
0011 #include <linux/types.h>
0012 #include <linux/list.h>
0013 #include <linux/cpumask.h>
0014 #include <linux/init.h>
0015 #include <linux/smp_types.h>
0016
0017 typedef void (*smp_call_func_t)(void *info);
0018 typedef bool (*smp_cond_func_t)(int cpu, void *info);
0019
0020 /*
0021  * structure shares (partial) layout with struct irq_work
0022  */
0023 struct __call_single_data {
0024     struct __call_single_node node;
0025     smp_call_func_t func;
0026     void *info;
0027 };
0028
0029 #define CSD_INIT(_func, _info) \
0030     (struct __call_single_data){ .func = (_func), .info = (_info), }
0031
0032 /* Use __aligned() to avoid to use 2 cache lines for 1 csd */
0033 typedef struct __call_single_data call_single_data_t
0034     __aligned(sizeof(struct __call_single_data));
0035
0036 #define INIT_CSD(_csd, _func, _info)        \
0037 do {                        \
0038     *(_csd) = CSD_INIT((_func), (_info));   \
0039 } while (0)
0040
0041 /*
0042  * Enqueue a llist_node on the call_single_queue; be very careful, read
0043  * flush_smp_call_function_queue() in detail.
0044  */
0045 extern void __smp_call_single_queue(int cpu, struct llist_node *node);
0046
0047 /* total number of cpus in this system (may exceed NR_CPUS) */
0048 extern unsigned int total_cpus;
0049
0050 int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
0051                  int wait);
0052
0053 void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
0054                void *info, bool wait, const struct cpumask *mask);
0055
0056 int smp_call_function_single_async(int cpu, struct __call_single_data *csd);
0057
0058 /*
0059  * Cpus stopping functions in panic. All have default weak definitions.
0060  * Architecture-dependent code may override them.
0061  */
0062 void panic_smp_self_stop(void);
0063 void nmi_panic_self_stop(struct pt_regs *regs);
0064 void crash_smp_send_stop(void);
0065
0066 /*
0067  * Call a function on all processors
0068  */
0069 static inline void on_each_cpu(smp_call_func_t func, void *info, int wait)
0070 {
0071     on_each_cpu_cond_mask(NULL, func, info, wait, cpu_online_mask);
0072 }
0073
0074 /**
0075  * on_each_cpu_mask(): Run a function on processors specified by
0076  * cpumask, which may include the local processor.
0077  * @mask: The set of cpus to run on (only runs on online subset).
0078  * @func: The function to run. This must be fast and non-blocking.
0079  * @info: An arbitrary pointer to pass to the function.
0080  * @wait: If true, wait (atomically) until function has completed
0081  *        on other CPUs.
0082  *
0083  * If @wait is true, then returns once @func has returned.
0084  *
0085  * You must not call this function with disabled interrupts or from a
0086  * hardware interrupt handler or from a bottom half handler.  The
0087  * exception is that it may be used during early boot while
0088  * early_boot_irqs_disabled is set.
0089  */
0090 static inline void on_each_cpu_mask(const struct cpumask *mask,
0091                     smp_call_func_t func, void *info, bool wait)
0092 {
0093     on_each_cpu_cond_mask(NULL, func, info, wait, mask);
0094 }
0095
0096 /*
0097  * Call a function on each processor for which the supplied function
0098  * cond_func returns a positive value. This may include the local
0099  * processor.  May be used during early boot while early_boot_irqs_disabled is
0100  * set. Use local_irq_save/restore() instead of local_irq_disable/enable().
0101  */
0102 static inline void on_each_cpu_cond(smp_cond_func_t cond_func,
0103                     smp_call_func_t func, void *info, bool wait)
0104 {
0105     on_each_cpu_cond_mask(cond_func, func, info, wait, cpu_online_mask);
0106 }
0107
0108 #ifdef CONFIG_SMP
0109
0110 #include <linux/preempt.h>
0111 #include <linux/compiler.h>
0112 #include <linux/thread_info.h>
0113 #include <asm/smp.h>
0114
0115 /*
0116  * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
0117  * (defined in asm header):
0118  */
0119
0120 /*
0121  * stops all CPUs but the current one:
0122  */
0123 extern void smp_send_stop(void);
0124
0125 /*
0126  * sends a 'reschedule' event to another CPU:
0127  */
0128 extern void smp_send_reschedule(int cpu);
0129
0130
0131 /*
0132  * Prepare machine for booting other CPUs.
0133  */
0134 extern void smp_prepare_cpus(unsigned int max_cpus);
0135
0136 /*
0137  * Bring a CPU up
0138  */
0139 extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
0140
0141 /*
0142  * Final polishing of CPUs
0143  */
0144 extern void smp_cpus_done(unsigned int max_cpus);
0145
0146 /*
0147  * Call a function on all other processors
0148  */
0149 void smp_call_function(smp_call_func_t func, void *info, int wait);
0150 void smp_call_function_many(const struct cpumask *mask,
0151                 smp_call_func_t func, void *info, bool wait);
0152
0153 int smp_call_function_any(const struct cpumask *mask,
0154               smp_call_func_t func, void *info, int wait);
0155
0156 void kick_all_cpus_sync(void);
0157 void wake_up_all_idle_cpus(void);
0158
0159 /*
0160  * Generic and arch helpers
0161  */
0162 void __init call_function_init(void);
0163 void generic_smp_call_function_single_interrupt(void);
0164 #define generic_smp_call_function_interrupt \
0165     generic_smp_call_function_single_interrupt
0166
0167 /*
0168  * Mark the boot cpu "online" so that it can call console drivers in
0169  * printk() and can access its per-cpu storage.
0170  */
0171 void smp_prepare_boot_cpu(void);
0172
0173 extern unsigned int setup_max_cpus;
0174 extern void __init setup_nr_cpu_ids(void);
0175 extern void __init smp_init(void);
0176
0177 extern int __boot_cpu_id;
0178
0179 static inline int get_boot_cpu_id(void)
0180 {
0181     return __boot_cpu_id;
0182 }
0183
0184 #else /* !SMP */
0185
0186 static inline void smp_send_stop(void) { }
0187
0188 /*
0189  *  These macros fold the SMP functionality into a single CPU system
0190  */
0191 #define raw_smp_processor_id()          0
0192 static inline void up_smp_call_function(smp_call_func_t func, void *info)
0193 {
0194 }
0195 #define smp_call_function(func, info, wait) \
0196             (up_smp_call_function(func, info))
0197
0198 static inline void smp_send_reschedule(int cpu) { }
0199 #define smp_prepare_boot_cpu()          do {} while (0)
0200 #define smp_call_function_many(mask, func, info, wait) \
0201             (up_smp_call_function(func, info))
0202 static inline void call_function_init(void) { }
0203
0204 static inline int
0205 smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
0206               void *info, int wait)
0207 {
0208     return smp_call_function_single(0, func, info, wait);
0209 }
0210
0211 static inline void kick_all_cpus_sync(void) {  }
0212 static inline void wake_up_all_idle_cpus(void) {  }
0213
0214 #ifdef CONFIG_UP_LATE_INIT
0215 extern void __init up_late_init(void);
0216 static inline void smp_init(void) { up_late_init(); }
0217 #else
0218 static inline void smp_init(void) { }
0219 #endif
0220
0221 static inline int get_boot_cpu_id(void)
0222 {
0223     return 0;
0224 }
0225
0226 #endif /* !SMP */
0227
0228 /**
0229  * raw_processor_id() - get the current (unstable) CPU id
0230  *
0231  * For then you know what you are doing and need an unstable
0232  * CPU id.
0233  */
0234
0235 /**
0236  * smp_processor_id() - get the current (stable) CPU id
0237  *
0238  * This is the normal accessor to the CPU id and should be used
0239  * whenever possible.
0240  *
0241  * The CPU id is stable when:
0242  *
0243  *  - IRQs are disabled;
0244  *  - preemption is disabled;
0245  *  - the task is CPU affine.
0246  *
0247  * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN
0248  * when smp_processor_id() is used when the CPU id is not stable.
0249  */
0250
0251 /*
0252  * Allow the architecture to differentiate between a stable and unstable read.
0253  * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a
0254  * regular asm read for the stable.
0255  */
0256 #ifndef __smp_processor_id
0257 #define __smp_processor_id(x) raw_smp_processor_id(x)
0258 #endif
0259
0260 #ifdef CONFIG_DEBUG_PREEMPT
0261   extern unsigned int debug_smp_processor_id(void);
0262 # define smp_processor_id() debug_smp_processor_id()
0263 #else
0264 # define smp_processor_id() __smp_processor_id()
0265 #endif
0266
0267 #define get_cpu()       ({ preempt_disable(); __smp_processor_id(); })
0268 #define put_cpu()       preempt_enable()
0269
0270 /*
0271  * Callback to arch code if there's nosmp or maxcpus=0 on the
0272  * boot command line:
0273  */
0274 extern void arch_disable_smp_support(void);
0275
0276 extern void arch_thaw_secondary_cpus_begin(void);
0277 extern void arch_thaw_secondary_cpus_end(void);
0278
0279 void smp_setup_processor_id(void);
0280
0281 int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par,
0282             bool phys);
0283
0284 /* SMP core functions */
0285 int smpcfd_prepare_cpu(unsigned int cpu);
0286 int smpcfd_dead_cpu(unsigned int cpu);
0287 int smpcfd_dying_cpu(unsigned int cpu);
0288
0289 #endif /* __LINUX_SMP_H */