39c715b717
This patch implements a number of smp_processor_id() cleanup ideas that
Arjan van de Ven and I came up with.
The previous __smp_processor_id/_smp_processor_id/smp_processor_id API
spaghetti was hard to follow both on the implementational and on the
usage side.
Some of the complexity arose from picking wrong names, some of the
complexity comes from the fact that not all architectures defined
__smp_processor_id.
In the new code, there are two externally visible symbols:
- smp_processor_id(): debug variant.
- raw_smp_processor_id(): nondebug variant. Replaces all existing
uses of _smp_processor_id() and __smp_processor_id(). Defined
by every SMP architecture in include/asm-*/smp.h.
There is one new internal symbol, dependent on DEBUG_PREEMPT:
- debug_smp_processor_id(): internal debug variant, mapped to
smp_processor_id().
Also, i moved debug_smp_processor_id() from lib/kernel_lock.c into a new
lib/smp_processor_id.c file. All related comments got updated and/or
clarified.
I have build/boot tested the following 8 .config combinations on x86:
{SMP,UP} x {PREEMPT,!PREEMPT} x {DEBUG_PREEMPT,!DEBUG_PREEMPT}
I have also build/boot tested x64 on UP/PREEMPT/DEBUG_PREEMPT. (Other
architectures are untested, but should work just fine.)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
131 lines
3.3 KiB
C
131 lines
3.3 KiB
C
#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/config.h>
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extern void cpu_idle(void);
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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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#include <asm/bug.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);
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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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extern int smp_call_function (void (*func) (void *info), void *info,
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int retry, int wait);
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/*
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* Call a function on all processors
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*/
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static inline int on_each_cpu(void (*func) (void *info), void *info,
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int retry, int wait)
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{
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int ret = 0;
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preempt_disable();
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ret = smp_call_function(func, info, retry, wait);
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func(info);
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preempt_enable();
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return ret;
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}
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#define MSG_ALL_BUT_SELF 0x8000 /* Assume <32768 CPU's */
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#define MSG_ALL 0x8001
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#define MSG_INVALIDATE_TLB 0x0001 /* Remote processor TLB invalidate */
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#define MSG_STOP_CPU 0x0002 /* Sent to shut down slave CPU's
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* when rebooting
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*/
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#define MSG_RESCHEDULE 0x0003 /* Reschedule request from master CPU*/
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#define MSG_CALL_FUNCTION 0x0004 /* Call function on all other CPUs */
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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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#else /* !SMP */
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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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#define hard_smp_processor_id() 0
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#define smp_call_function(func,info,retry,wait) ({ 0; })
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#define on_each_cpu(func,info,retry,wait) ({ func(info); 0; })
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static inline void smp_send_reschedule(int cpu) { }
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#define num_booting_cpus() 1
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#define smp_prepare_boot_cpu() do {} while (0)
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#endif /* !SMP */
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/*
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* smp_processor_id(): get the current CPU ID.
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*
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* if DEBUG_PREEMPT is enabled the we check whether it is
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* used in a preemption-safe way. (smp_processor_id() is safe
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* if it's used in a preemption-off critical section, or in
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* a thread that is bound to the current CPU.)
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*
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* NOTE: raw_smp_processor_id() is for internal use only
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* (smp_processor_id() is the preferred variant), but in rare
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* instances it might also be used to turn off false positives
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* (i.e. smp_processor_id() use that the debugging code reports but
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* which use for some reason is legal). Don't use this to hack around
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* the warning message, as your code might not work under PREEMPT.
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*/
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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() raw_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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#define put_cpu_no_resched() preempt_enable_no_resched()
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#endif /* __LINUX_SMP_H */
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