linux-stable/include/linux/smp.h
Paul E. McKenney e48c15b796 smp: Add source and destination CPUs to __call_single_data
This commit adds a destination CPU to __call_single_data, and is inspired
by an earlier commit by Peter Zijlstra.  This version adds #ifdef to
permit use by 32-bit systems and supplying the destination CPU for all
smp_call_function*() requests, not just smp_call_function_single().

If need be, 32-bit systems could be accommodated by shrinking the flags
field to 16 bits (the atomic_t variant is currently unused) and by
providing only eight bits for CPU on such systems.

It is not clear that the addition of the fields to __call_single_node
are really needed.

[ paulmck: Apply Boqun Feng feedback on 32-bit builds. ]
Link: https://lore.kernel.org/lkml/20200615164048.GC2531@hirez.programming.kicks-ass.net/
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-09-04 11:50:50 -07:00

261 lines
6.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __LINUX_SMP_H
#define __LINUX_SMP_H
/*
* Generic SMP support
* Alan Cox. <alan@redhat.com>
*/
#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>
typedef void (*smp_call_func_t)(void *info);
typedef bool (*smp_cond_func_t)(int cpu, void *info);
/*
* structure shares (partial) layout with struct irq_work
*/
struct __call_single_data {
union {
struct __call_single_node node;
struct {
struct llist_node llist;
unsigned int flags;
#ifdef CONFIG_64BIT
u16 src, dst;
#endif
};
};
smp_call_func_t func;
void *info;
};
/* Use __aligned() to avoid to use 2 cache lines for 1 csd */
typedef struct __call_single_data call_single_data_t
__aligned(sizeof(struct __call_single_data));
/*
* 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);
/*
* Call a function on all processors
*/
void on_each_cpu(smp_call_func_t func, void *info, int wait);
/*
* Call a function on processors specified by mask, which might include
* the local one.
*/
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.
*/
void on_each_cpu_cond(smp_cond_func_t cond_func, smp_call_func_t func,
void *info, bool 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);
#ifdef CONFIG_SMP
#include <linux/preempt.h>
#include <linux/kernel.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 smp_send_reschedule(int 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 \
generic_smp_call_function_single_interrupt
/*
* Mark the boot cpu "online" so that it can call console drivers in
* printk() and can access its per-cpu storage.
*/
void smp_prepare_boot_cpu(void);
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)
{
return __boot_cpu_id;
}
#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() 0
static inline void up_smp_call_function(smp_call_func_t func, void *info)
{
}
#define smp_call_function(func, info, wait) \
(up_smp_call_function(func, info))
static inline void smp_send_reschedule(int cpu) { }
#define smp_prepare_boot_cpu() do {} while (0)
#define smp_call_function_many(mask, func, info, wait) \
(up_smp_call_function(func, info))
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) { }
#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(x) raw_smp_processor_id(x)
#endif
#ifdef CONFIG_DEBUG_PREEMPT
extern unsigned int debug_smp_processor_id(void);
# define smp_processor_id() debug_smp_processor_id()
#else
# define smp_processor_id() __smp_processor_id()
#endif
#define get_cpu() ({ preempt_disable(); __smp_processor_id(); })
#define put_cpu() preempt_enable()
/*
* 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 */