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[PATCH] lockdep: irqtrace subsystem, core 

Accurate hard-IRQ-flags and softirq-flags state tracing.

This allows us to attach extra functionality to IRQ flags on/off
events (such as trace-on/off).

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Ingo Molnar 2006-07-03 00:24:42 -07:00 committed by Linus Torvalds
parent 5bdc9b447c
commit de30a2b355
10 changed files with 313 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/powerpc/kernel/irq.c
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@ -429,7 +429,7 @@ void do_softirq(void)
local_bh_disable();
do_softirq_onstack();
account_system_vtime(current);
__local_bh_enable();
_local_bh_enable();
}
local_irq_restore(flags);

31
include/asm-powerpc/irqflags.h Normal file
View File

@ -0,0 +1,31 @@
/*
* include/asm-powerpc/irqflags.h
*
* IRQ flags handling
*
* This file gets included from lowlevel asm headers too, to provide
* wrapped versions of the local_irq_*() APIs, based on the
* raw_local_irq_*() macros from the lowlevel headers.
*/
#ifndef _ASM_IRQFLAGS_H
#define _ASM_IRQFLAGS_H
/*
* Get definitions for raw_local_save_flags(x), etc.
*/
#include <asm-powerpc/hw_irq.h>
/*
* Do the CPU's IRQ-state tracing from assembly code. We call a
* C function, so save all the C-clobbered registers:
*/
#ifdef CONFIG_TRACE_IRQFLAGS
#error No support on PowerPC yet for CONFIG_TRACE_IRQFLAGS
#else
# define TRACE_IRQS_ON
# define TRACE_IRQS_OFF
#endif
#endif

26
include/linux/hardirq.h
View File

@ -86,9 +86,6 @@ extern void synchronize_irq(unsigned int irq);
# define synchronize_irq(irq) barrier()
#endif
#define nmi_enter() irq_enter()
#define nmi_exit() sub_preempt_count(HARDIRQ_OFFSET)
struct task_struct;
#ifndef CONFIG_VIRT_CPU_ACCOUNTING
@ -97,12 +94,35 @@ static inline void account_system_vtime(struct task_struct *tsk)
}
#endif
/*
* It is safe to do non-atomic ops on ->hardirq_context,
* because NMI handlers may not preempt and the ops are
* always balanced, so the interrupted value of ->hardirq_context
* will always be restored.
*/
#define irq_enter() \
do { \
account_system_vtime(current); \
add_preempt_count(HARDIRQ_OFFSET); \
trace_hardirq_enter(); \
} while (0)
/*
* Exit irq context without processing softirqs:
*/
#define __irq_exit() \
do { \
trace_hardirq_exit(); \
account_system_vtime(current); \
sub_preempt_count(HARDIRQ_OFFSET); \
} while (0)
/*
* Exit irq context and process softirqs if needed:
*/
extern void irq_exit(void);
#define nmi_enter() irq_enter()
#define nmi_exit() __irq_exit()
#endif /* LINUX_HARDIRQ_H */

2
include/linux/init_task.h
View File

@ -3,6 +3,7 @@
#include <linux/file.h>
#include <linux/rcupdate.h>
#include <linux/irqflags.h>
#define INIT_FDTABLE \
{ \
@ -124,6 +125,7 @@ extern struct group_info init_groups;
.cpu_timers = INIT_CPU_TIMERS(tsk.cpu_timers), \
.fs_excl = ATOMIC_INIT(0), \
.pi_lock = SPIN_LOCK_UNLOCKED, \
INIT_TRACE_IRQFLAGS \
}

11
include/linux/interrupt.h
View File

@ -10,6 +10,7 @@
#include <linux/irqreturn.h>
#include <linux/hardirq.h>
#include <linux/sched.h>
#include <linux/irqflags.h>
#include <asm/atomic.h>
#include <asm/ptrace.h>
#include <asm/system.h>
@ -199,13 +200,11 @@ static inline void __deprecated save_and_cli(unsigned long *x)
#define save_and_cli(x) save_and_cli(&x)
#endif /* CONFIG_SMP */
/* SoftIRQ primitives. */
#define local_bh_disable() \
do { add_preempt_count(SOFTIRQ_OFFSET); barrier(); } while (0)
#define __local_bh_enable() \
do { barrier(); sub_preempt_count(SOFTIRQ_OFFSET); } while (0)
extern void local_bh_disable(void);
extern void __local_bh_enable(void);
extern void _local_bh_enable(void);
extern void local_bh_enable(void);
extern void local_bh_enable_ip(unsigned long ip);
/* PLEASE, avoid to allocate new softirqs, if you need not _really_ high
frequency threaded job scheduling. For almost all the purposes

96
include/linux/irqflags.h Normal file
View File

@ -0,0 +1,96 @@
/*
* include/linux/irqflags.h
*
* IRQ flags tracing: follow the state of the hardirq and softirq flags and
* provide callbacks for transitions between ON and OFF states.
*
* This file gets included from lowlevel asm headers too, to provide
* wrapped versions of the local_irq_*() APIs, based on the
* raw_local_irq_*() macros from the lowlevel headers.
*/
#ifndef _LINUX_TRACE_IRQFLAGS_H
#define _LINUX_TRACE_IRQFLAGS_H
#ifdef CONFIG_TRACE_IRQFLAGS
extern void trace_hardirqs_on(void);
extern void trace_hardirqs_off(void);
extern void trace_softirqs_on(unsigned long ip);
extern void trace_softirqs_off(unsigned long ip);
# define trace_hardirq_context(p) ((p)->hardirq_context)
# define trace_softirq_context(p) ((p)->softirq_context)
# define trace_hardirqs_enabled(p) ((p)->hardirqs_enabled)
# define trace_softirqs_enabled(p) ((p)->softirqs_enabled)
# define trace_hardirq_enter() do { current->hardirq_context++; } while (0)
# define trace_hardirq_exit() do { current->hardirq_context--; } while (0)
# define trace_softirq_enter() do { current->softirq_context++; } while (0)
# define trace_softirq_exit() do { current->softirq_context--; } while (0)
# define INIT_TRACE_IRQFLAGS .softirqs_enabled = 1,
#else
# define trace_hardirqs_on() do { } while (0)
# define trace_hardirqs_off() do { } while (0)
# define trace_softirqs_on(ip) do { } while (0)
# define trace_softirqs_off(ip) do { } while (0)
# define trace_hardirq_context(p) 0
# define trace_softirq_context(p) 0
# define trace_hardirqs_enabled(p) 0
# define trace_softirqs_enabled(p) 0
# define trace_hardirq_enter() do { } while (0)
# define trace_hardirq_exit() do { } while (0)
# define trace_softirq_enter() do { } while (0)
# define trace_softirq_exit() do { } while (0)
# define INIT_TRACE_IRQFLAGS
#endif
#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
#include <asm/irqflags.h>
#define local_irq_enable() \
do { trace_hardirqs_on(); raw_local_irq_enable(); } while (0)
#define local_irq_disable() \
do { raw_local_irq_disable(); trace_hardirqs_off(); } while (0)
#define local_irq_save(flags) \
do { raw_local_irq_save(flags); trace_hardirqs_off(); } while (0)
#define local_irq_restore(flags) \
do { \
if (raw_irqs_disabled_flags(flags)) { \
raw_local_irq_restore(flags); \
trace_hardirqs_off(); \
} else { \
trace_hardirqs_on(); \
raw_local_irq_restore(flags); \
} \
} while (0)
#else /* !CONFIG_TRACE_IRQFLAGS_SUPPORT */
/*
* The local_irq_*() APIs are equal to the raw_local_irq*()
* if !TRACE_IRQFLAGS.
*/
# define raw_local_irq_disable() local_irq_disable()
# define raw_local_irq_enable() local_irq_enable()
# define raw_local_irq_save(flags) local_irq_save(flags)
# define raw_local_irq_restore(flags) local_irq_restore(flags)
#endif /* CONFIG_TRACE_IRQFLAGS_SUPPORT */
#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
#define safe_halt() \
do { \
trace_hardirqs_on(); \
raw_safe_halt(); \
} while (0)
#define local_save_flags(flags) raw_local_save_flags(flags)
#define irqs_disabled() \
({ \
unsigned long flags; \
\
raw_local_save_flags(flags); \
raw_irqs_disabled_flags(flags); \
})
#define irqs_disabled_flags(flags) raw_irqs_disabled_flags(flags)
#endif /* CONFIG_X86 */
#endif

15
include/linux/sched.h
View File

@ -871,6 +871,21 @@ struct task_struct {
/* mutex deadlock detection */
struct mutex_waiter *blocked_on;
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
unsigned int irq_events;
int hardirqs_enabled;
unsigned long hardirq_enable_ip;
unsigned int hardirq_enable_event;
unsigned long hardirq_disable_ip;
unsigned int hardirq_disable_event;
int softirqs_enabled;
unsigned long softirq_disable_ip;
unsigned int softirq_disable_event;
unsigned long softirq_enable_ip;
unsigned int softirq_enable_event;
int hardirq_context;
int softirq_context;
#endif
/* journalling filesystem info */
void *journal_info;

19
kernel/fork.c
View File

@ -968,6 +968,10 @@ static task_t *copy_process(unsigned long clone_flags,
if (!p)
goto fork_out;
#ifdef CONFIG_TRACE_IRQFLAGS
DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled);
DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled);
#endif
retval = -EAGAIN;
if (atomic_read(&p->user->processes) >=
p->signal->rlim[RLIMIT_NPROC].rlim_cur) {
@ -1042,6 +1046,21 @@ static task_t *copy_process(unsigned long clone_flags,
}
mpol_fix_fork_child_flag(p);
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
p->irq_events = 0;
p->hardirqs_enabled = 0;
p->hardirq_enable_ip = 0;
p->hardirq_enable_event = 0;
p->hardirq_disable_ip = _THIS_IP_;
p->hardirq_disable_event = 0;
p->softirqs_enabled = 1;
p->softirq_enable_ip = _THIS_IP_;
p->softirq_enable_event = 0;
p->softirq_disable_ip = 0;
p->softirq_disable_event = 0;
p->hardirq_context = 0;
p->softirq_context = 0;
#endif
rt_mutex_init_task(p);

4
kernel/sched.c
View File

@ -4462,7 +4462,9 @@ int __sched cond_resched_softirq(void)
BUG_ON(!in_softirq());
if (need_resched() && __resched_legal()) {
__local_bh_enable();
raw_local_irq_disable();
_local_bh_enable();
raw_local_irq_enable();
__cond_resched();
local_bh_disable();
return 1;

137
kernel/softirq.c
View File

@ -61,6 +61,119 @@ static inline void wakeup_softirqd(void)
wake_up_process(tsk);
}
/*
* This one is for softirq.c-internal use,
* where hardirqs are disabled legitimately:
*/
static void __local_bh_disable(unsigned long ip)
{
unsigned long flags;
WARN_ON_ONCE(in_irq());
raw_local_irq_save(flags);
add_preempt_count(SOFTIRQ_OFFSET);
/*
* Were softirqs turned off above:
*/
if (softirq_count() == SOFTIRQ_OFFSET)
trace_softirqs_off(ip);
raw_local_irq_restore(flags);
}
void local_bh_disable(void)
{
__local_bh_disable((unsigned long)__builtin_return_address(0));
}
EXPORT_SYMBOL(local_bh_disable);
void __local_bh_enable(void)
{
WARN_ON_ONCE(in_irq());
/*
* softirqs should never be enabled by __local_bh_enable(),
* it always nests inside local_bh_enable() sections:
*/
WARN_ON_ONCE(softirq_count() == SOFTIRQ_OFFSET);
sub_preempt_count(SOFTIRQ_OFFSET);
}
EXPORT_SYMBOL_GPL(__local_bh_enable);
/*
* Special-case - softirqs can safely be enabled in
* cond_resched_softirq(), or by __do_softirq(),
* without processing still-pending softirqs:
*/
void _local_bh_enable(void)
{
WARN_ON_ONCE(in_irq());
WARN_ON_ONCE(!irqs_disabled());
if (softirq_count() == SOFTIRQ_OFFSET)
trace_softirqs_on((unsigned long)__builtin_return_address(0));
sub_preempt_count(SOFTIRQ_OFFSET);
}
EXPORT_SYMBOL(_local_bh_enable);
void local_bh_enable(void)
{
unsigned long flags;
WARN_ON_ONCE(in_irq());
WARN_ON_ONCE(irqs_disabled());
local_irq_save(flags);
/*
* Are softirqs going to be turned on now:
*/
if (softirq_count() == SOFTIRQ_OFFSET)
trace_softirqs_on((unsigned long)__builtin_return_address(0));
/*
* Keep preemption disabled until we are done with
* softirq processing:
*/
sub_preempt_count(SOFTIRQ_OFFSET - 1);
if (unlikely(!in_interrupt() && local_softirq_pending()))
do_softirq();
dec_preempt_count();
local_irq_restore(flags);
preempt_check_resched();
}
EXPORT_SYMBOL(local_bh_enable);
void local_bh_enable_ip(unsigned long ip)
{
unsigned long flags;
WARN_ON_ONCE(in_irq());
local_irq_save(flags);
/*
* Are softirqs going to be turned on now:
*/
if (softirq_count() == SOFTIRQ_OFFSET)
trace_softirqs_on(ip);
/*
* Keep preemption disabled until we are done with
* softirq processing:
*/
sub_preempt_count(SOFTIRQ_OFFSET - 1);
if (unlikely(!in_interrupt() && local_softirq_pending()))
do_softirq();
dec_preempt_count();
local_irq_restore(flags);
preempt_check_resched();
}
EXPORT_SYMBOL(local_bh_enable_ip);
/*
* We restart softirq processing MAX_SOFTIRQ_RESTART times,
* and we fall back to softirqd after that.
@ -80,8 +193,9 @@ asmlinkage void __do_softirq(void)
int cpu;
pending = local_softirq_pending();
__local_bh_disable((unsigned long)__builtin_return_address(0));
trace_softirq_enter();
local_bh_disable();
cpu = smp_processor_id();
restart:
/* Reset the pending bitmask before enabling irqs */
@ -109,7 +223,8 @@ restart:
if (pending)
wakeup_softirqd();
__local_bh_enable();
trace_softirq_exit();
_local_bh_enable();
}
#ifndef __ARCH_HAS_DO_SOFTIRQ
@ -136,23 +251,6 @@ EXPORT_SYMBOL(do_softirq);
#endif
void local_bh_enable(void)
{
WARN_ON(irqs_disabled());
/*
* Keep preemption disabled until we are done with
* softirq processing:
*/
sub_preempt_count(SOFTIRQ_OFFSET - 1);
if (unlikely(!in_interrupt() && local_softirq_pending()))
do_softirq();
dec_preempt_count();
preempt_check_resched();
}
EXPORT_SYMBOL(local_bh_enable);
#ifdef __ARCH_IRQ_EXIT_IRQS_DISABLED
# define invoke_softirq() __do_softirq()
#else
@ -165,6 +263,7 @@ EXPORT_SYMBOL(local_bh_enable);
void irq_exit(void)
{
account_system_vtime(current);
trace_hardirq_exit();
sub_preempt_count(IRQ_EXIT_OFFSET);
if (!in_interrupt() && local_softirq_pending())
invoke_softirq();