diff options
| -rw-r--r-- | arch/powerpc/kernel/irq.c | 2 | ||||
| -rw-r--r-- | include/asm-powerpc/irqflags.h | 31 | ||||
| -rw-r--r-- | include/linux/hardirq.h | 26 | ||||
| -rw-r--r-- | include/linux/init_task.h | 2 | ||||
| -rw-r--r-- | include/linux/interrupt.h | 11 | ||||
| -rw-r--r-- | include/linux/irqflags.h | 96 | ||||
| -rw-r--r-- | include/linux/sched.h | 15 | ||||
| -rw-r--r-- | kernel/fork.c | 19 | ||||
| -rw-r--r-- | kernel/sched.c | 4 | ||||
| -rw-r--r-- | kernel/softirq.c | 137 |
10 files changed, 313 insertions, 30 deletions
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c index 525baab45d2d..027728b95429 100644 --- a/arch/powerpc/kernel/irq.c +++ b/arch/powerpc/kernel/irq.c @@ -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); diff --git a/include/asm-powerpc/irqflags.h b/include/asm-powerpc/irqflags.h new file mode 100644 index 000000000000..7970cbaeaa54 --- /dev/null +++ b/include/asm-powerpc/irqflags.h @@ -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 diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h index 114ae583cca9..b1d4332b5cf0 100644 --- a/include/linux/hardirq.h +++ b/include/linux/hardirq.h @@ -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 */ diff --git a/include/linux/init_task.h b/include/linux/init_task.h index 1b7bb37624bb..444a3ae0de2a 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -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 \ } diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 73463fbb38e4..d5afee95fd43 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -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 diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h new file mode 100644 index 000000000000..412e025bc5c7 --- /dev/null +++ b/include/linux/irqflags.h @@ -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 diff --git a/include/linux/sched.h b/include/linux/sched.h index bdabeee10a78..ad7a89014d29 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -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; diff --git a/kernel/fork.c b/kernel/fork.c index 1cd46a4fb0d3..b7db7fb74f53 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -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); diff --git a/kernel/sched.c b/kernel/sched.c index 48c1faa60a67..911829966534 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -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; diff --git a/kernel/softirq.c b/kernel/softirq.c index 8f03e3b89b55..584609b6a66e 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -62,6 +62,119 @@ static inline void wakeup_softirqd(void) } /* + * 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(); |