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![Linus Torvalds](/assets/img/avatar_default.png)
- Two fixes for the futex syscall related to the timeout handling.
FUTEX_LOCK_PI does not support the FUTEX_CLOCK_REALTIME bit and because
it's not set the time namespace adjustment for clock MONOTONIC is
applied wrongly.
FUTEX_WAIT cannot support the FUTEX_CLOCK_REALTIME bit because its
always a relative timeout.
- Cleanups in the futex syscall entry points which became obvious when
the two timeout handling bugs were fixed.
- Cleanup of queued_write_lock_slowpath() as suggested by Linus
- Fixup of the smp_call_function_single_async() prototype
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Merge tag 'locking-urgent-2021-05-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Thomas Gleixner:
"A set of locking related fixes and updates:
- Two fixes for the futex syscall related to the timeout handling.
FUTEX_LOCK_PI does not support the FUTEX_CLOCK_REALTIME bit and
because it's not set the time namespace adjustment for clock
MONOTONIC is applied wrongly.
FUTEX_WAIT cannot support the FUTEX_CLOCK_REALTIME bit because its
always a relative timeout.
- Cleanups in the futex syscall entry points which became obvious
when the two timeout handling bugs were fixed.
- Cleanup of queued_write_lock_slowpath() as suggested by Linus
- Fixup of the smp_call_function_single_async() prototype"
* tag 'locking-urgent-2021-05-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
futex: Make syscall entry points less convoluted
futex: Get rid of the val2 conditional dance
futex: Do not apply time namespace adjustment on FUTEX_LOCK_PI
Revert 337f13046f
("futex: Allow FUTEX_CLOCK_REALTIME with FUTEX_WAIT op")
locking/qrwlock: Cleanup queued_write_lock_slowpath()
smp: Fix smp_call_function_single_async prototype
290 lines
7.6 KiB
C
290 lines
7.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_SMP_H
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#define __LINUX_SMP_H
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/*
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* Generic SMP support
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* Alan Cox. <alan@redhat.com>
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*/
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#include <linux/errno.h>
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#include <linux/types.h>
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#include <linux/list.h>
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#include <linux/cpumask.h>
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#include <linux/init.h>
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#include <linux/smp_types.h>
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typedef void (*smp_call_func_t)(void *info);
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typedef bool (*smp_cond_func_t)(int cpu, void *info);
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/*
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* structure shares (partial) layout with struct irq_work
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*/
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struct __call_single_data {
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struct __call_single_node node;
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smp_call_func_t func;
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void *info;
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};
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#define CSD_INIT(_func, _info) \
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(struct __call_single_data){ .func = (_func), .info = (_info), }
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/* Use __aligned() to avoid to use 2 cache lines for 1 csd */
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typedef struct __call_single_data call_single_data_t
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__aligned(sizeof(struct __call_single_data));
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#define INIT_CSD(_csd, _func, _info) \
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do { \
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*(_csd) = CSD_INIT((_func), (_info)); \
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} while (0)
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/*
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* Enqueue a llist_node on the call_single_queue; be very careful, read
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* flush_smp_call_function_queue() in detail.
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*/
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extern void __smp_call_single_queue(int cpu, struct llist_node *node);
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/* total number of cpus in this system (may exceed NR_CPUS) */
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extern unsigned int total_cpus;
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int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
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int wait);
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void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
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void *info, bool wait, const struct cpumask *mask);
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int smp_call_function_single_async(int cpu, struct __call_single_data *csd);
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/*
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* Cpus stopping functions in panic. All have default weak definitions.
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* Architecture-dependent code may override them.
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*/
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void panic_smp_self_stop(void);
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void nmi_panic_self_stop(struct pt_regs *regs);
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void crash_smp_send_stop(void);
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/*
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* Call a function on all processors
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*/
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static inline void on_each_cpu(smp_call_func_t func, void *info, int wait)
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{
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on_each_cpu_cond_mask(NULL, func, info, wait, cpu_online_mask);
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}
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/**
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* on_each_cpu_mask(): Run a function on processors specified by
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* cpumask, which may include the local processor.
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* @mask: The set of cpus to run on (only runs on online subset).
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* @func: The function to run. This must be fast and non-blocking.
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* @info: An arbitrary pointer to pass to the function.
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* @wait: If true, wait (atomically) until function has completed
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* on other CPUs.
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*
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* If @wait is true, then returns once @func has returned.
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*
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* You must not call this function with disabled interrupts or from a
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* hardware interrupt handler or from a bottom half handler. The
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* exception is that it may be used during early boot while
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* early_boot_irqs_disabled is set.
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*/
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static inline void on_each_cpu_mask(const struct cpumask *mask,
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smp_call_func_t func, void *info, bool wait)
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{
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on_each_cpu_cond_mask(NULL, func, info, wait, mask);
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}
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/*
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* Call a function on each processor for which the supplied function
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* cond_func returns a positive value. This may include the local
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* processor. May be used during early boot while early_boot_irqs_disabled is
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* set. Use local_irq_save/restore() instead of local_irq_disable/enable().
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*/
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static inline void on_each_cpu_cond(smp_cond_func_t cond_func,
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smp_call_func_t func, void *info, bool wait)
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{
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on_each_cpu_cond_mask(cond_func, func, info, wait, cpu_online_mask);
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}
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#ifdef CONFIG_SMP
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#include <linux/preempt.h>
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#include <linux/kernel.h>
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#include <linux/compiler.h>
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#include <linux/thread_info.h>
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#include <asm/smp.h>
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/*
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* main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
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* (defined in asm header):
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*/
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/*
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* stops all CPUs but the current one:
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*/
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extern void smp_send_stop(void);
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/*
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* sends a 'reschedule' event to another CPU:
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*/
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extern void smp_send_reschedule(int cpu);
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/*
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* Prepare machine for booting other CPUs.
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*/
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extern void smp_prepare_cpus(unsigned int max_cpus);
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/*
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* Bring a CPU up
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*/
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extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
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/*
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* Final polishing of CPUs
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*/
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extern void smp_cpus_done(unsigned int max_cpus);
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/*
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* Call a function on all other processors
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*/
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void smp_call_function(smp_call_func_t func, void *info, int wait);
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void smp_call_function_many(const struct cpumask *mask,
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smp_call_func_t func, void *info, bool wait);
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int smp_call_function_any(const struct cpumask *mask,
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smp_call_func_t func, void *info, int wait);
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void kick_all_cpus_sync(void);
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void wake_up_all_idle_cpus(void);
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/*
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* Generic and arch helpers
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*/
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void __init call_function_init(void);
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void generic_smp_call_function_single_interrupt(void);
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#define generic_smp_call_function_interrupt \
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generic_smp_call_function_single_interrupt
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/*
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* Mark the boot cpu "online" so that it can call console drivers in
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* printk() and can access its per-cpu storage.
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*/
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void smp_prepare_boot_cpu(void);
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extern unsigned int setup_max_cpus;
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extern void __init setup_nr_cpu_ids(void);
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extern void __init smp_init(void);
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extern int __boot_cpu_id;
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static inline int get_boot_cpu_id(void)
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{
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return __boot_cpu_id;
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}
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#else /* !SMP */
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static inline void smp_send_stop(void) { }
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/*
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* These macros fold the SMP functionality into a single CPU system
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*/
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#define raw_smp_processor_id() 0
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static inline void up_smp_call_function(smp_call_func_t func, void *info)
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{
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}
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#define smp_call_function(func, info, wait) \
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(up_smp_call_function(func, info))
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static inline void smp_send_reschedule(int cpu) { }
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#define smp_prepare_boot_cpu() do {} while (0)
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#define smp_call_function_many(mask, func, info, wait) \
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(up_smp_call_function(func, info))
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static inline void call_function_init(void) { }
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static inline int
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smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
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void *info, int wait)
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{
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return smp_call_function_single(0, func, info, wait);
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}
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static inline void kick_all_cpus_sync(void) { }
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static inline void wake_up_all_idle_cpus(void) { }
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#ifdef CONFIG_UP_LATE_INIT
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extern void __init up_late_init(void);
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static inline void smp_init(void) { up_late_init(); }
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#else
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static inline void smp_init(void) { }
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#endif
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static inline int get_boot_cpu_id(void)
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{
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return 0;
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}
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#endif /* !SMP */
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/**
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* raw_processor_id() - get the current (unstable) CPU id
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*
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* For then you know what you are doing and need an unstable
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* CPU id.
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*/
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/**
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* smp_processor_id() - get the current (stable) CPU id
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*
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* This is the normal accessor to the CPU id and should be used
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* whenever possible.
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*
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* The CPU id is stable when:
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*
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* - IRQs are disabled;
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* - preemption is disabled;
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* - the task is CPU affine.
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*
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* When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN
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* when smp_processor_id() is used when the CPU id is not stable.
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*/
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/*
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* Allow the architecture to differentiate between a stable and unstable read.
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* For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a
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* regular asm read for the stable.
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*/
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#ifndef __smp_processor_id
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#define __smp_processor_id(x) raw_smp_processor_id(x)
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#endif
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#ifdef CONFIG_DEBUG_PREEMPT
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extern unsigned int debug_smp_processor_id(void);
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# define smp_processor_id() debug_smp_processor_id()
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#else
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# define smp_processor_id() __smp_processor_id()
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#endif
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#define get_cpu() ({ preempt_disable(); __smp_processor_id(); })
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#define put_cpu() preempt_enable()
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/*
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* Callback to arch code if there's nosmp or maxcpus=0 on the
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* boot command line:
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*/
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extern void arch_disable_smp_support(void);
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extern void arch_thaw_secondary_cpus_begin(void);
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extern void arch_thaw_secondary_cpus_end(void);
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void smp_setup_processor_id(void);
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int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par,
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bool phys);
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/* SMP core functions */
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int smpcfd_prepare_cpu(unsigned int cpu);
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int smpcfd_dead_cpu(unsigned int cpu);
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int smpcfd_dying_cpu(unsigned int cpu);
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#endif /* __LINUX_SMP_H */
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