X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=include%2Flinux%2Fhardirq.h;h=d5b387669dab1f044406826847fdfa7646ab829d;hb=29c71b138c83c8191f1f7e46fcc28b9d6bc8a5dd;hp=b1d4332b5cf0f22e2bf6f2fabf6aadb0b41f1680;hpb=de30a2b355ea85350ca2f58f3b9bf4e5bc007986;p=safe%2Fjmp%2Flinux-2.6 diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h index b1d4332..d5b3876 100644 --- a/include/linux/hardirq.h +++ b/include/linux/hardirq.h @@ -2,7 +2,11 @@ #define LINUX_HARDIRQ_H #include +#ifdef CONFIG_PREEMPT #include +#endif +#include +#include #include #include @@ -13,50 +17,67 @@ * - bits 0-7 are the preemption count (max preemption depth: 256) * - bits 8-15 are the softirq count (max # of softirqs: 256) * - * The hardirq count can be overridden per architecture, the default is: + * The hardirq count can in theory reach the same as NR_IRQS. + * In reality, the number of nested IRQS is limited to the stack + * size as well. For archs with over 1000 IRQS it is not practical + * to expect that they will all nest. We give a max of 10 bits for + * hardirq nesting. An arch may choose to give less than 10 bits. + * m68k expects it to be 8. * - * - bits 16-27 are the hardirq count (max # of hardirqs: 4096) - * - ( bit 28 is the PREEMPT_ACTIVE flag. ) + * - bits 16-25 are the hardirq count (max # of nested hardirqs: 1024) + * - bit 26 is the NMI_MASK + * - bit 28 is the PREEMPT_ACTIVE flag * * PREEMPT_MASK: 0x000000ff * SOFTIRQ_MASK: 0x0000ff00 - * HARDIRQ_MASK: 0x0fff0000 + * HARDIRQ_MASK: 0x03ff0000 + * NMI_MASK: 0x04000000 */ #define PREEMPT_BITS 8 #define SOFTIRQ_BITS 8 +#define NMI_BITS 1 + +#define MAX_HARDIRQ_BITS 10 #ifndef HARDIRQ_BITS -#define HARDIRQ_BITS 12 -/* - * The hardirq mask has to be large enough to have space for potentially - * all IRQ sources in the system nesting on a single CPU. - */ -#if (1 << HARDIRQ_BITS) < NR_IRQS -# error HARDIRQ_BITS is too low! +# define HARDIRQ_BITS MAX_HARDIRQ_BITS #endif + +#if HARDIRQ_BITS > MAX_HARDIRQ_BITS +#error HARDIRQ_BITS too high! #endif #define PREEMPT_SHIFT 0 #define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS) #define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS) +#define NMI_SHIFT (HARDIRQ_SHIFT + HARDIRQ_BITS) #define __IRQ_MASK(x) ((1UL << (x))-1) #define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT) #define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT) #define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT) +#define NMI_MASK (__IRQ_MASK(NMI_BITS) << NMI_SHIFT) #define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT) #define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT) #define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT) +#define NMI_OFFSET (1UL << NMI_SHIFT) + +#ifndef PREEMPT_ACTIVE +#define PREEMPT_ACTIVE_BITS 1 +#define PREEMPT_ACTIVE_SHIFT (NMI_SHIFT + NMI_BITS) +#define PREEMPT_ACTIVE (__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT) +#endif -#if PREEMPT_ACTIVE < (1 << (HARDIRQ_SHIFT + HARDIRQ_BITS)) +#if PREEMPT_ACTIVE < (1 << (NMI_SHIFT + NMI_BITS)) #error PREEMPT_ACTIVE is too low! #endif #define hardirq_count() (preempt_count() & HARDIRQ_MASK) #define softirq_count() (preempt_count() & SOFTIRQ_MASK) -#define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK)) +#define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \ + | NMI_MASK)) /* * Are we doing bottom half or hardware interrupt processing? @@ -66,12 +87,35 @@ #define in_softirq() (softirq_count()) #define in_interrupt() (irq_count()) -#if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL) -# define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != kernel_locked()) +/* + * Are we in NMI context? + */ +#define in_nmi() (preempt_count() & NMI_MASK) + +#if defined(CONFIG_PREEMPT) +# define PREEMPT_INATOMIC_BASE kernel_locked() +# define PREEMPT_CHECK_OFFSET 1 #else -# define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != 0) +# define PREEMPT_INATOMIC_BASE 0 +# define PREEMPT_CHECK_OFFSET 0 #endif +/* + * Are we running in atomic context? WARNING: this macro cannot + * always detect atomic context; in particular, it cannot know about + * held spinlocks in non-preemptible kernels. Thus it should not be + * used in the general case to determine whether sleeping is possible. + * Do not use in_atomic() in driver code. + */ +#define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_INATOMIC_BASE) + +/* + * Check whether we were atomic before we did preempt_disable(): + * (used by the scheduler, *after* releasing the kernel lock) + */ +#define in_atomic_preempt_off() \ + ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET) + #ifdef CONFIG_PREEMPT # define preemptible() (preempt_count() == 0 && !irqs_disabled()) # define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1) @@ -80,7 +124,7 @@ # define IRQ_EXIT_OFFSET HARDIRQ_OFFSET #endif -#ifdef CONFIG_SMP +#if defined(CONFIG_SMP) || defined(CONFIG_GENERIC_HARDIRQS) extern void synchronize_irq(unsigned int irq); #else # define synchronize_irq(irq) barrier() @@ -94,13 +138,49 @@ static inline void account_system_vtime(struct task_struct *tsk) } #endif +#if defined(CONFIG_NO_HZ) +#if defined(CONFIG_TINY_RCU) +extern void rcu_enter_nohz(void); +extern void rcu_exit_nohz(void); + +static inline void rcu_irq_enter(void) +{ + rcu_exit_nohz(); +} + +static inline void rcu_irq_exit(void) +{ + rcu_enter_nohz(); +} + +static inline void rcu_nmi_enter(void) +{ +} + +static inline void rcu_nmi_exit(void) +{ +} + +#else +extern void rcu_irq_enter(void); +extern void rcu_irq_exit(void); +extern void rcu_nmi_enter(void); +extern void rcu_nmi_exit(void); +#endif +#else +# define rcu_irq_enter() do { } while (0) +# define rcu_irq_exit() do { } while (0) +# define rcu_nmi_enter() do { } while (0) +# define rcu_nmi_exit() do { } while (0) +#endif /* #if defined(CONFIG_NO_HZ) */ + /* * 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() \ +#define __irq_enter() \ do { \ account_system_vtime(current); \ add_preempt_count(HARDIRQ_OFFSET); \ @@ -108,6 +188,11 @@ static inline void account_system_vtime(struct task_struct *tsk) } while (0) /* + * Enter irq context (on NO_HZ, update jiffies): + */ +extern void irq_enter(void); + +/* * Exit irq context without processing softirqs: */ #define __irq_exit() \ @@ -122,7 +207,24 @@ static inline void account_system_vtime(struct task_struct *tsk) */ extern void irq_exit(void); -#define nmi_enter() irq_enter() -#define nmi_exit() __irq_exit() +#define nmi_enter() \ + do { \ + ftrace_nmi_enter(); \ + BUG_ON(in_nmi()); \ + add_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \ + lockdep_off(); \ + rcu_nmi_enter(); \ + trace_hardirq_enter(); \ + } while (0) + +#define nmi_exit() \ + do { \ + trace_hardirq_exit(); \ + rcu_nmi_exit(); \ + lockdep_on(); \ + BUG_ON(!in_nmi()); \ + sub_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \ + ftrace_nmi_exit(); \ + } while (0) #endif /* LINUX_HARDIRQ_H */