1#ifndef LINUX_HARDIRQ_H 2#define LINUX_HARDIRQ_H 3 4#include <linux/preempt.h> 5#include <linux/lockdep.h> 6#include <linux/ftrace_irq.h> 7#include <asm/hardirq.h> 8 9/* 10 * We put the hardirq and softirq counter into the preemption 11 * counter. The bitmask has the following meaning: 12 * 13 * - bits 0-7 are the preemption count (max preemption depth: 256) 14 * - bits 8-15 are the softirq count (max # of softirqs: 256) 15 * 16 * The hardirq count can in theory reach the same as NR_IRQS. 17 * In reality, the number of nested IRQS is limited to the stack 18 * size as well. For archs with over 1000 IRQS it is not practical 19 * to expect that they will all nest. We give a max of 10 bits for 20 * hardirq nesting. An arch may choose to give less than 10 bits. 21 * m68k expects it to be 8. 22 * 23 * - bits 16-25 are the hardirq count (max # of nested hardirqs: 1024) 24 * - bit 26 is the NMI_MASK 25 * - bit 28 is the PREEMPT_ACTIVE flag 26 * 27 * PREEMPT_MASK: 0x000000ff 28 * SOFTIRQ_MASK: 0x0000ff00 29 * HARDIRQ_MASK: 0x03ff0000 30 * NMI_MASK: 0x04000000 31 */ 32#define PREEMPT_BITS 8 33#define SOFTIRQ_BITS 8 34#define NMI_BITS 1 35 36#define MAX_HARDIRQ_BITS 10 37 38#ifndef HARDIRQ_BITS 39# define HARDIRQ_BITS MAX_HARDIRQ_BITS 40#endif 41 42#if HARDIRQ_BITS > MAX_HARDIRQ_BITS 43#error HARDIRQ_BITS too high! 44#endif 45 46#define PREEMPT_SHIFT 0 47#define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS) 48#define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS) 49#define NMI_SHIFT (HARDIRQ_SHIFT + HARDIRQ_BITS) 50 51#define __IRQ_MASK(x) ((1UL << (x))-1) 52 53#define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT) 54#define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT) 55#define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT) 56#define NMI_MASK (__IRQ_MASK(NMI_BITS) << NMI_SHIFT) 57 58#define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT) 59#define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT) 60#define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT) 61#define NMI_OFFSET (1UL << NMI_SHIFT) 62 63#define SOFTIRQ_DISABLE_OFFSET (2 * SOFTIRQ_OFFSET) 64 65#ifndef PREEMPT_ACTIVE 66#define PREEMPT_ACTIVE_BITS 1 67#define PREEMPT_ACTIVE_SHIFT (NMI_SHIFT + NMI_BITS) 68#define PREEMPT_ACTIVE (__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT) 69#endif 70 71#if PREEMPT_ACTIVE < (1 << (NMI_SHIFT + NMI_BITS)) 72#error PREEMPT_ACTIVE is too low! 73#endif 74 75#define hardirq_count() (preempt_count() & HARDIRQ_MASK) 76#define softirq_count() (preempt_count() & SOFTIRQ_MASK) 77#define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \ 78 | NMI_MASK)) 79 80/* 81 * Are we doing bottom half or hardware interrupt processing? 82 * Are we in a softirq context? Interrupt context? 83 * in_softirq - Are we currently processing softirq or have bh disabled? 84 * in_serving_softirq - Are we currently processing softirq? 85 */ 86#define in_irq() (hardirq_count()) 87#define in_softirq() (softirq_count()) 88#define in_interrupt() (irq_count()) 89#define in_serving_softirq() (softirq_count() & SOFTIRQ_OFFSET) 90 91/* 92 * Are we in NMI context? 93 */ 94#define in_nmi() (preempt_count() & NMI_MASK) 95 96#if defined(CONFIG_PREEMPT) && defined(CONFIG_BKL) 97# include <linux/sched.h> 98# define PREEMPT_INATOMIC_BASE (current->lock_depth >= 0) 99#else 100# define PREEMPT_INATOMIC_BASE 0 101#endif 102 103#if defined(CONFIG_PREEMPT) 104# define PREEMPT_CHECK_OFFSET 1 105#else 106# define PREEMPT_CHECK_OFFSET 0 107#endif 108 109/* 110 * Are we running in atomic context? WARNING: this macro cannot 111 * always detect atomic context; in particular, it cannot know about 112 * held spinlocks in non-preemptible kernels. Thus it should not be 113 * used in the general case to determine whether sleeping is possible. 114 * Do not use in_atomic() in driver code. 115 */ 116#define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_INATOMIC_BASE) 117 118/* 119 * Check whether we were atomic before we did preempt_disable(): 120 * (used by the scheduler, *after* releasing the kernel lock) 121 */ 122#define in_atomic_preempt_off() \ 123 ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET) 124 125#ifdef CONFIG_PREEMPT 126# define preemptible() (preempt_count() == 0 && !irqs_disabled()) 127# define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1) 128#else 129# define preemptible() 0 130# define IRQ_EXIT_OFFSET HARDIRQ_OFFSET 131#endif 132 133#if defined(CONFIG_SMP) || defined(CONFIG_GENERIC_HARDIRQS) 134extern void synchronize_irq(unsigned int irq); 135#else 136# define synchronize_irq(irq) barrier() 137#endif 138 139struct task_struct; 140 141#if !defined(CONFIG_VIRT_CPU_ACCOUNTING) && !defined(CONFIG_IRQ_TIME_ACCOUNTING) 142static inline void account_system_vtime(struct task_struct *tsk) 143{ 144} 145#else 146extern void account_system_vtime(struct task_struct *tsk); 147#endif 148 149#if defined(CONFIG_NO_HZ) 150#if defined(CONFIG_TINY_RCU) || defined(CONFIG_TINY_PREEMPT_RCU) 151extern void rcu_enter_nohz(void); 152extern void rcu_exit_nohz(void); 153 154static inline void rcu_irq_enter(void) 155{ 156 rcu_exit_nohz(); 157} 158 159static inline void rcu_irq_exit(void) 160{ 161 rcu_enter_nohz(); 162} 163 164static inline void rcu_nmi_enter(void) 165{ 166} 167 168static inline void rcu_nmi_exit(void) 169{ 170} 171 172#else 173extern void rcu_irq_enter(void); 174extern void rcu_irq_exit(void); 175extern void rcu_nmi_enter(void); 176extern void rcu_nmi_exit(void); 177#endif 178#else 179# define rcu_irq_enter() do { } while (0) 180# define rcu_irq_exit() do { } while (0) 181# define rcu_nmi_enter() do { } while (0) 182# define rcu_nmi_exit() do { } while (0) 183#endif /* #if defined(CONFIG_NO_HZ) */ 184 185/* 186 * It is safe to do non-atomic ops on ->hardirq_context, 187 * because NMI handlers may not preempt and the ops are 188 * always balanced, so the interrupted value of ->hardirq_context 189 * will always be restored. 190 */ 191#define __irq_enter() \ 192 do { \ 193 account_system_vtime(current); \ 194 add_preempt_count(HARDIRQ_OFFSET); \ 195 trace_hardirq_enter(); \ 196 } while (0) 197 198/* 199 * Enter irq context (on NO_HZ, update jiffies): 200 */ 201extern void irq_enter(void); 202 203/* 204 * Exit irq context without processing softirqs: 205 */ 206#define __irq_exit() \ 207 do { \ 208 trace_hardirq_exit(); \ 209 account_system_vtime(current); \ 210 sub_preempt_count(HARDIRQ_OFFSET); \ 211 } while (0) 212 213/* 214 * Exit irq context and process softirqs if needed: 215 */ 216extern void irq_exit(void); 217 218#define nmi_enter() \ 219 do { \ 220 ftrace_nmi_enter(); \ 221 BUG_ON(in_nmi()); \ 222 add_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \ 223 lockdep_off(); \ 224 rcu_nmi_enter(); \ 225 trace_hardirq_enter(); \ 226 } while (0) 227 228#define nmi_exit() \ 229 do { \ 230 trace_hardirq_exit(); \ 231 rcu_nmi_exit(); \ 232 lockdep_on(); \ 233 BUG_ON(!in_nmi()); \ 234 sub_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \ 235 ftrace_nmi_exit(); \ 236 } while (0) 237 238#endif /* LINUX_HARDIRQ_H */ 239