forked from mirrors/linux
		
	 0784181b44
			
		
	
	
		0784181b44
		
	
	
	
	
		
			
			Add a function to check that an offline CPU has left the tracing
infrastructure in a sane state.
Commit 9bb69ba4c1 ("ACPI: processor_idle: use raw_safe_halt() in
acpi_idle_play_dead()") fixed an issue where the acpi_idle_play_dead()
function called safe_halt() instead of raw_safe_halt(), which had the
side-effect of setting the hardirqs_enabled flag for the offline CPU.
On x86 this triggered warnings from lockdep_assert_irqs_disabled() when
the CPU was brought back online again later. These warnings were too
early for the exception to be handled correctly, leading to a
triple-fault.
Add lockdep_cleanup_dead_cpu() to check for this kind of failure mode,
print the events leading up to it, and correct it so that the CPU can
come online again correctly. Re-introducing the original bug now merely
results in this warning instead:
[   61.556652] smpboot: CPU 1 is now offline
[   61.556769] CPU 1 left hardirqs enabled!
[   61.556915] irq event stamp: 128149
[   61.556965] hardirqs last  enabled at (128149): [<ffffffff81720a36>] acpi_idle_play_dead+0x46/0x70
[   61.557055] hardirqs last disabled at (128148): [<ffffffff81124d50>] do_idle+0x90/0xe0
[   61.557117] softirqs last  enabled at (128078): [<ffffffff81cec74c>] __do_softirq+0x31c/0x423
[   61.557199] softirqs last disabled at (128065): [<ffffffff810baae1>] __irq_exit_rcu+0x91/0x100
[boqun: Capitalize the title and reword the message a bit]
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/f7bd2b3b999051bb3ef4be34526a9262008285f5.camel@infradead.org
		
	
			
		
			
				
	
	
		
			271 lines
		
	
	
	
		
			8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			271 lines
		
	
	
	
		
			8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /* SPDX-License-Identifier: GPL-2.0 */
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| /*
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|  * include/linux/irqflags.h
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|  *
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|  * IRQ flags tracing: follow the state of the hardirq and softirq flags and
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|  * provide callbacks for transitions between ON and OFF states.
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|  *
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|  * This file gets included from lowlevel asm headers too, to provide
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|  * wrapped versions of the local_irq_*() APIs, based on the
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|  * raw_local_irq_*() macros from the lowlevel headers.
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|  */
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| #ifndef _LINUX_TRACE_IRQFLAGS_H
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| #define _LINUX_TRACE_IRQFLAGS_H
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| 
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| #include <linux/irqflags_types.h>
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| #include <linux/typecheck.h>
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| #include <linux/cleanup.h>
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| #include <asm/irqflags.h>
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| #include <asm/percpu.h>
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| 
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| struct task_struct;
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| 
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| /* Currently lockdep_softirqs_on/off is used only by lockdep */
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| #ifdef CONFIG_PROVE_LOCKING
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|   extern void lockdep_softirqs_on(unsigned long ip);
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|   extern void lockdep_softirqs_off(unsigned long ip);
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|   extern void lockdep_hardirqs_on_prepare(void);
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|   extern void lockdep_hardirqs_on(unsigned long ip);
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|   extern void lockdep_hardirqs_off(unsigned long ip);
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|   extern void lockdep_cleanup_dead_cpu(unsigned int cpu,
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| 				       struct task_struct *idle);
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| #else
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|   static inline void lockdep_softirqs_on(unsigned long ip) { }
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|   static inline void lockdep_softirqs_off(unsigned long ip) { }
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|   static inline void lockdep_hardirqs_on_prepare(void) { }
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|   static inline void lockdep_hardirqs_on(unsigned long ip) { }
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|   static inline void lockdep_hardirqs_off(unsigned long ip) { }
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|   static inline void lockdep_cleanup_dead_cpu(unsigned int cpu,
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| 					      struct task_struct *idle) {}
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| #endif
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| 
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| #ifdef CONFIG_TRACE_IRQFLAGS
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| 
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| DECLARE_PER_CPU(int, hardirqs_enabled);
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| DECLARE_PER_CPU(int, hardirq_context);
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| 
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| extern void trace_hardirqs_on_prepare(void);
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| extern void trace_hardirqs_off_finish(void);
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| extern void trace_hardirqs_on(void);
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| extern void trace_hardirqs_off(void);
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| 
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| # define lockdep_hardirq_context()	(raw_cpu_read(hardirq_context))
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| # define lockdep_softirq_context(p)	((p)->softirq_context)
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| # define lockdep_hardirqs_enabled()	(this_cpu_read(hardirqs_enabled))
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| # define lockdep_softirqs_enabled(p)	((p)->softirqs_enabled)
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| # define lockdep_hardirq_enter()			\
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| do {							\
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| 	if (__this_cpu_inc_return(hardirq_context) == 1)\
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| 		current->hardirq_threaded = 0;		\
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| } while (0)
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| # define lockdep_hardirq_threaded()		\
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| do {						\
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| 	current->hardirq_threaded = 1;		\
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| } while (0)
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| # define lockdep_hardirq_exit()			\
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| do {						\
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| 	__this_cpu_dec(hardirq_context);	\
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| } while (0)
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| 
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| # define lockdep_hrtimer_enter(__hrtimer)		\
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| ({							\
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| 	bool __expires_hardirq = true;			\
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| 							\
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| 	if (!__hrtimer->is_hard) {			\
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| 		current->irq_config = 1;		\
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| 		__expires_hardirq = false;		\
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| 	}						\
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| 	__expires_hardirq;				\
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| })
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| 
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| # define lockdep_hrtimer_exit(__expires_hardirq)	\
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| 	do {						\
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| 		if (!__expires_hardirq)			\
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| 			current->irq_config = 0;	\
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| 	} while (0)
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| 
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| # define lockdep_posixtimer_enter()				\
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| 	  do {							\
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| 		  current->irq_config = 1;			\
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| 	  } while (0)
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| 
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| # define lockdep_posixtimer_exit()				\
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| 	  do {							\
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| 		  current->irq_config = 0;			\
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| 	  } while (0)
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| 
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| # define lockdep_irq_work_enter(_flags)					\
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| 	  do {								\
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| 		  if (!((_flags) & IRQ_WORK_HARD_IRQ))			\
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| 			current->irq_config = 1;			\
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| 	  } while (0)
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| # define lockdep_irq_work_exit(_flags)					\
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| 	  do {								\
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| 		  if (!((_flags) & IRQ_WORK_HARD_IRQ))			\
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| 			current->irq_config = 0;			\
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| 	  } while (0)
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| 
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| #else
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| # define trace_hardirqs_on_prepare()		do { } while (0)
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| # define trace_hardirqs_off_finish()		do { } while (0)
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| # define trace_hardirqs_on()			do { } while (0)
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| # define trace_hardirqs_off()			do { } while (0)
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| # define lockdep_hardirq_context()		0
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| # define lockdep_softirq_context(p)		0
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| # define lockdep_hardirqs_enabled()		0
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| # define lockdep_softirqs_enabled(p)		0
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| # define lockdep_hardirq_enter()		do { } while (0)
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| # define lockdep_hardirq_threaded()		do { } while (0)
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| # define lockdep_hardirq_exit()			do { } while (0)
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| # define lockdep_softirq_enter()		do { } while (0)
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| # define lockdep_softirq_exit()			do { } while (0)
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| # define lockdep_hrtimer_enter(__hrtimer)	false
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| # define lockdep_hrtimer_exit(__context)	do { (void)(__context); } while (0)
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| # define lockdep_posixtimer_enter()		do { } while (0)
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| # define lockdep_posixtimer_exit()		do { } while (0)
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| # define lockdep_irq_work_enter(__work)		do { } while (0)
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| # define lockdep_irq_work_exit(__work)		do { } while (0)
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| #endif
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| 
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| #if defined(CONFIG_TRACE_IRQFLAGS) && !defined(CONFIG_PREEMPT_RT)
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| # define lockdep_softirq_enter()		\
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| do {						\
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| 	current->softirq_context++;		\
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| } while (0)
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| # define lockdep_softirq_exit()			\
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| do {						\
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| 	current->softirq_context--;		\
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| } while (0)
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| 
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| #else
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| # define lockdep_softirq_enter()		do { } while (0)
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| # define lockdep_softirq_exit()			do { } while (0)
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| #endif
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| 
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| #if defined(CONFIG_IRQSOFF_TRACER) || \
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| 	defined(CONFIG_PREEMPT_TRACER)
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|  extern void stop_critical_timings(void);
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|  extern void start_critical_timings(void);
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| #else
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| # define stop_critical_timings() do { } while (0)
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| # define start_critical_timings() do { } while (0)
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| #endif
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| 
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| #ifdef CONFIG_DEBUG_IRQFLAGS
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| extern void warn_bogus_irq_restore(void);
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| #define raw_check_bogus_irq_restore()			\
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| 	do {						\
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| 		if (unlikely(!arch_irqs_disabled()))	\
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| 			warn_bogus_irq_restore();	\
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| 	} while (0)
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| #else
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| #define raw_check_bogus_irq_restore() do { } while (0)
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| #endif
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| 
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| /*
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|  * Wrap the arch provided IRQ routines to provide appropriate checks.
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|  */
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| #define raw_local_irq_disable()		arch_local_irq_disable()
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| #define raw_local_irq_enable()		arch_local_irq_enable()
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| #define raw_local_irq_save(flags)			\
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| 	do {						\
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| 		typecheck(unsigned long, flags);	\
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| 		flags = arch_local_irq_save();		\
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| 	} while (0)
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| #define raw_local_irq_restore(flags)			\
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| 	do {						\
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| 		typecheck(unsigned long, flags);	\
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| 		raw_check_bogus_irq_restore();		\
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| 		arch_local_irq_restore(flags);		\
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| 	} while (0)
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| #define raw_local_save_flags(flags)			\
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| 	do {						\
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| 		typecheck(unsigned long, flags);	\
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| 		flags = arch_local_save_flags();	\
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| 	} while (0)
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| #define raw_irqs_disabled_flags(flags)			\
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| 	({						\
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| 		typecheck(unsigned long, flags);	\
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| 		arch_irqs_disabled_flags(flags);	\
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| 	})
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| #define raw_irqs_disabled()		(arch_irqs_disabled())
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| #define raw_safe_halt()			arch_safe_halt()
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| 
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| /*
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|  * The local_irq_*() APIs are equal to the raw_local_irq*()
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|  * if !TRACE_IRQFLAGS.
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|  */
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| #ifdef CONFIG_TRACE_IRQFLAGS
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| 
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| #define local_irq_enable()				\
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| 	do {						\
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| 		trace_hardirqs_on();			\
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| 		raw_local_irq_enable();			\
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| 	} while (0)
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| 
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| #define local_irq_disable()				\
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| 	do {						\
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| 		bool was_disabled = raw_irqs_disabled();\
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| 		raw_local_irq_disable();		\
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| 		if (!was_disabled)			\
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| 			trace_hardirqs_off();		\
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| 	} while (0)
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| 
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| #define local_irq_save(flags)				\
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| 	do {						\
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| 		raw_local_irq_save(flags);		\
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| 		if (!raw_irqs_disabled_flags(flags))	\
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| 			trace_hardirqs_off();		\
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| 	} while (0)
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| 
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| #define local_irq_restore(flags)			\
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| 	do {						\
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| 		if (!raw_irqs_disabled_flags(flags))	\
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| 			trace_hardirqs_on();		\
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| 		raw_local_irq_restore(flags);		\
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| 	} while (0)
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| 
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| #define safe_halt()				\
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| 	do {					\
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| 		trace_hardirqs_on();		\
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| 		raw_safe_halt();		\
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| 	} while (0)
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| 
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| 
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| #else /* !CONFIG_TRACE_IRQFLAGS */
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| 
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| #define local_irq_enable()	do { raw_local_irq_enable(); } while (0)
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| #define local_irq_disable()	do { raw_local_irq_disable(); } while (0)
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| #define local_irq_save(flags)	do { raw_local_irq_save(flags); } while (0)
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| #define local_irq_restore(flags) do { raw_local_irq_restore(flags); } while (0)
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| #define safe_halt()		do { raw_safe_halt(); } while (0)
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| 
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| #endif /* CONFIG_TRACE_IRQFLAGS */
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| 
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| #define local_save_flags(flags)	raw_local_save_flags(flags)
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| 
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| /*
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|  * Some architectures don't define arch_irqs_disabled(), so even if either
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|  * definition would be fine we need to use different ones for the time being
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|  * to avoid build issues.
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|  */
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| #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
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| #define irqs_disabled()					\
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| 	({						\
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| 		unsigned long _flags;			\
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| 		raw_local_save_flags(_flags);		\
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| 		raw_irqs_disabled_flags(_flags);	\
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| 	})
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| #else /* !CONFIG_TRACE_IRQFLAGS_SUPPORT */
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| #define irqs_disabled()	raw_irqs_disabled()
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| #endif /* CONFIG_TRACE_IRQFLAGS_SUPPORT */
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| 
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| #define irqs_disabled_flags(flags) raw_irqs_disabled_flags(flags)
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| 
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| DEFINE_LOCK_GUARD_0(irq, local_irq_disable(), local_irq_enable())
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| DEFINE_LOCK_GUARD_0(irqsave,
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| 		    local_irq_save(_T->flags),
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| 		    local_irq_restore(_T->flags),
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| 		    unsigned long flags)
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| 
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| #endif
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