commit 1139aeb1c521eb4a050920ce6c64c36c4f2a3ab7 upstream. As of commit966a967116
("smp: Avoid using two cache lines for struct call_single_data"), the smp code prefers 32-byte aligned call_single_data objects for performance reasons, but the block layer includes an instance of this structure in the main 'struct request' that is more senstive to size than to performance here, see4ccafe0320
("block: unalign call_single_data in struct request"). The result is a violation of the calling conventions that clang correctly points out: block/blk-mq.c:630:39: warning: passing 8-byte aligned argument to 32-byte aligned parameter 2 of 'smp_call_function_single_async' may result in an unaligned pointer access [-Walign-mismatch] smp_call_function_single_async(cpu, &rq->csd); It does seem that the usage of the call_single_data without cache line alignment should still be allowed by the smp code, so just change the function prototype so it accepts both, but leave the default alignment unchanged for the other users. This seems better to me than adding a local hack to shut up an otherwise correct warning in the caller. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Jens Axboe <axboe@kernel.dk> Link: https://lkml.kernel.org/r/20210505211300.3174456-1-arnd@kernel.org [nc: Fix conflicts, modify rq_csd_init] Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
262 lines
6.4 KiB
C
262 lines
6.4 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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union {
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struct __call_single_node node;
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struct {
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struct llist_node llist;
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unsigned int flags;
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#ifdef CONFIG_64BIT
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u16 src, dst;
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#endif
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};
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};
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smp_call_func_t func;
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void *info;
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};
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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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/*
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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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/*
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* Call a function on all processors
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*/
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void on_each_cpu(smp_call_func_t func, void *info, int wait);
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/*
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* Call a function on processors specified by mask, which might include
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* the local one.
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*/
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void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
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void *info, bool wait);
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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.
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*/
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void on_each_cpu_cond(smp_cond_func_t cond_func, smp_call_func_t func,
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void *info, bool 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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#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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