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