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