/* SPDX-License-Identifier: GPL-2.0 */ #ifndef __LINUX_SMP_H #define __LINUX_SMP_H /* * Generic SMP support * Alan Cox. <[email protected]> */ #include <linux/errno.h> #include <linux/types.h> #include <linux/list.h> #include <linux/cpumask.h> #include <linux/init.h> #include <linux/smp_types.h> smp_call_func_t; smp_cond_func_t; /* * structure shares (partial) layout with struct irq_work */ struct __call_single_data { … }; #define CSD_INIT(_func, _info) … /* Use __aligned() to avoid to use 2 cache lines for 1 csd */ call_single_data_t __aligned(…); #define INIT_CSD(_csd, _func, _info) … /* * Enqueue a llist_node on the call_single_queue; be very careful, read * flush_smp_call_function_queue() in detail. */ extern void __smp_call_single_queue(int cpu, struct llist_node *node); /* total number of cpus in this system (may exceed NR_CPUS) */ extern unsigned int total_cpus; int smp_call_function_single(int cpuid, smp_call_func_t func, void *info, int wait); void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func, void *info, bool wait, const struct cpumask *mask); int smp_call_function_single_async(int cpu, call_single_data_t *csd); /* * Cpus stopping functions in panic. All have default weak definitions. * Architecture-dependent code may override them. */ void __noreturn panic_smp_self_stop(void); void __noreturn nmi_panic_self_stop(struct pt_regs *regs); void crash_smp_send_stop(void); /* * Call a function on all processors */ static inline void on_each_cpu(smp_call_func_t func, void *info, int wait) { … } /** * on_each_cpu_mask(): Run a function on processors specified by * cpumask, which may include the local processor. * @mask: The set of cpus to run on (only runs on online subset). * @func: The function to run. This must be fast and non-blocking. * @info: An arbitrary pointer to pass to the function. * @wait: If true, wait (atomically) until function has completed * on other CPUs. * * If @wait is true, then returns once @func has returned. * * You must not call this function with disabled interrupts or from a * hardware interrupt handler or from a bottom half handler. The * exception is that it may be used during early boot while * early_boot_irqs_disabled is set. */ static inline void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func, void *info, bool wait) { … } /* * Call a function on each processor for which the supplied function * cond_func returns a positive value. This may include the local * processor. May be used during early boot while early_boot_irqs_disabled is * set. Use local_irq_save/restore() instead of local_irq_disable/enable(). */ static inline void on_each_cpu_cond(smp_cond_func_t cond_func, smp_call_func_t func, void *info, bool wait) { … } /* * Architecture specific boot CPU setup. Defined as empty weak function in * init/main.c. Architectures can override it. */ void smp_prepare_boot_cpu(void); #ifdef CONFIG_SMP #include <linux/preempt.h> #include <linux/compiler.h> #include <linux/thread_info.h> #include <asm/smp.h> /* * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc. * (defined in asm header): */ /* * stops all CPUs but the current one: */ extern void smp_send_stop(void); /* * sends a 'reschedule' event to another CPU: */ extern void arch_smp_send_reschedule(int cpu); /* * scheduler_ipi() is inline so can't be passed as callback reason, but the * callsite IP should be sufficient for root-causing IPIs sent from here. */ #define smp_send_reschedule(cpu) … /* * Prepare machine for booting other CPUs. */ extern void smp_prepare_cpus(unsigned int max_cpus); /* * Bring a CPU up */ extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle); /* * Final polishing of CPUs */ extern void smp_cpus_done(unsigned int max_cpus); /* * Call a function on all other processors */ void smp_call_function(smp_call_func_t func, void *info, int wait); void smp_call_function_many(const struct cpumask *mask, smp_call_func_t func, void *info, bool wait); int smp_call_function_any(const struct cpumask *mask, smp_call_func_t func, void *info, int wait); void kick_all_cpus_sync(void); void wake_up_all_idle_cpus(void); /* * Generic and arch helpers */ void __init call_function_init(void); void generic_smp_call_function_single_interrupt(void); #define generic_smp_call_function_interrupt … extern unsigned int setup_max_cpus; extern void __init setup_nr_cpu_ids(void); extern void __init smp_init(void); extern int __boot_cpu_id; static inline int get_boot_cpu_id(void) { … } #else /* !SMP */ static inline void smp_send_stop(void) { } /* * These macros fold the SMP functionality into a single CPU system */ #define raw_smp_processor_id … static inline void up_smp_call_function(smp_call_func_t func, void *info) { } #define smp_call_function … static inline void smp_send_reschedule(int cpu) { } #define smp_call_function_many … static inline void call_function_init(void) { } static inline int smp_call_function_any(const struct cpumask *mask, smp_call_func_t func, void *info, int wait) { return smp_call_function_single(0, func, info, wait); } static inline void kick_all_cpus_sync(void) { } static inline void wake_up_all_idle_cpus(void) { } #define setup_max_cpus … #ifdef CONFIG_UP_LATE_INIT extern void __init up_late_init(void); static inline void smp_init(void) { up_late_init(); } #else static inline void smp_init(void) { } #endif static inline int get_boot_cpu_id(void) { return 0; } #endif /* !SMP */ /** * raw_processor_id() - get the current (unstable) CPU id * * For then you know what you are doing and need an unstable * CPU id. */ /** * smp_processor_id() - get the current (stable) CPU id * * This is the normal accessor to the CPU id and should be used * whenever possible. * * The CPU id is stable when: * * - IRQs are disabled; * - preemption is disabled; * - the task is CPU affine. * * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN * when smp_processor_id() is used when the CPU id is not stable. */ /* * Allow the architecture to differentiate between a stable and unstable read. * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a * regular asm read for the stable. */ #ifndef __smp_processor_id #define __smp_processor_id … #endif #ifdef CONFIG_DEBUG_PREEMPT extern unsigned int debug_smp_processor_id(void); #define smp_processor_id() … #else #define smp_processor_id … #endif #define get_cpu() … #define put_cpu() … /* * Callback to arch code if there's nosmp or maxcpus=0 on the * boot command line: */ extern void arch_disable_smp_support(void); extern void arch_thaw_secondary_cpus_begin(void); extern void arch_thaw_secondary_cpus_end(void); void smp_setup_processor_id(void); int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys); /* SMP core functions */ int smpcfd_prepare_cpu(unsigned int cpu); int smpcfd_dead_cpu(unsigned int cpu); int smpcfd_dying_cpu(unsigned int cpu); #endif /* __LINUX_SMP_H */
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