Linux/kernel/irq

Version: ~ [ linux-6.11.5 ] ~ [ linux-6.10.14 ] ~ [ linux-6.9.12 ] ~ [ linux-6.8.12 ] ~ [ linux-6.7.12 ] ~ [ linux-6.6.58 ] ~ [ linux-6.5.13 ] ~ [ linux-6.4.16 ] ~ [ linux-6.3.13 ] ~ [ linux-6.2.16 ] ~ [ linux-6.1.114 ] ~ [ linux-6.0.19 ] ~ [ linux-5.19.17 ] ~ [ linux-5.18.19 ] ~ [ linux-5.17.15 ] ~ [ linux-5.16.20 ] ~ [ linux-5.15.169 ] ~ [ linux-5.14.21 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.228 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.284 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.322 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.336 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.337 ] ~ [ linux-4.4.302 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.9 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

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1 // SPDX-License-Identifier: GPL-2.0-only << 2 /* 1 /* 3 * Copyright (C) 2010 Red Hat, Inc., Peter Zij 2 * Copyright (C) 2010 Red Hat, Inc., Peter Zijlstra 4 * 3 * 5 * Provides a framework for enqueueing and run 4 * Provides a framework for enqueueing and running callbacks from hardirq 6 * context. The enqueueing is NMI-safe. 5 * context. The enqueueing is NMI-safe. 7 */ 6 */ 8 7 9 #include <linux/bug.h> 8 #include <linux/bug.h> 10 #include <linux/kernel.h> 9 #include <linux/kernel.h> 11 #include <linux/export.h> 10 #include <linux/export.h> 12 #include <linux/irq_work.h> 11 #include <linux/irq_work.h> 13 #include <linux/percpu.h> 12 #include <linux/percpu.h> 14 #include <linux/hardirq.h> 13 #include <linux/hardirq.h> 15 #include <linux/irqflags.h> 14 #include <linux/irqflags.h> 16 #include <linux/sched.h> 15 #include <linux/sched.h> 17 #include <linux/tick.h> 16 #include <linux/tick.h> 18 #include <linux/cpu.h> 17 #include <linux/cpu.h> 19 #include <linux/notifier.h> 18 #include <linux/notifier.h> 20 #include <linux/smp.h> 19 #include <linux/smp.h> 21 #include <linux/smpboot.h> << 22 #include <asm/processor.h> 20 #include <asm/processor.h> 23 #include <linux/kasan.h> << 24 21 25 #include <trace/events/ipi.h> << 26 22 27 static DEFINE_PER_CPU(struct llist_head, raise 23 static DEFINE_PER_CPU(struct llist_head, raised_list); 28 static DEFINE_PER_CPU(struct llist_head, lazy_ 24 static DEFINE_PER_CPU(struct llist_head, lazy_list); 29 static DEFINE_PER_CPU(struct task_struct *, ir << 30 << 31 static void wake_irq_workd(void) << 32 { << 33 struct task_struct *tsk = __this_cpu_r << 34 << 35 if (!llist_empty(this_cpu_ptr(&lazy_li << 36 wake_up_process(tsk); << 37 } << 38 << 39 #ifdef CONFIG_SMP << 40 static void irq_work_wake(struct irq_work *ent << 41 { << 42 wake_irq_workd(); << 43 } << 44 << 45 static DEFINE_PER_CPU(struct irq_work, irq_wor << 46 IRQ_WORK_INIT_HARD(irq_work_wake); << 47 #endif << 48 << 49 static int irq_workd_should_run(unsigned int c << 50 { << 51 return !llist_empty(this_cpu_ptr(&lazy << 52 } << 53 25 54 /* 26 /* 55 * Claim the entry so that no one else will po 27 * Claim the entry so that no one else will poke at it. 56 */ 28 */ 57 static bool irq_work_claim(struct irq_work *wo 29 static bool irq_work_claim(struct irq_work *work) 58 { 30 { 59 int oflags; !! 31 unsigned long flags, oflags, nflags; 60 32 61 oflags = atomic_fetch_or(IRQ_WORK_CLAI << 62 /* 33 /* 63 * If the work is already pending, no !! 34 * Start with our best wish as a premise but only trust any 64 * The pairing smp_mb() in irq_work_si !! 35 * flag value after cmpxchg() result. 65 * everything we did before is visible << 66 */ 36 */ 67 if (oflags & IRQ_WORK_PENDING) !! 37 flags = work->flags & ~IRQ_WORK_PENDING; 68 return false; !! 38 for (;;) { >> 39 nflags = flags | IRQ_WORK_CLAIMED; >> 40 oflags = cmpxchg(&work->flags, flags, nflags); >> 41 if (oflags == flags) >> 42 break; >> 43 if (oflags & IRQ_WORK_PENDING) >> 44 return false; >> 45 flags = oflags; >> 46 cpu_relax(); >> 47 } >> 48 69 return true; 49 return true; 70 } 50 } 71 51 72 void __weak arch_irq_work_raise(void) 52 void __weak arch_irq_work_raise(void) 73 { 53 { 74 /* 54 /* 75 * Lame architectures will get the tim 55 * Lame architectures will get the timer tick callback 76 */ 56 */ 77 } 57 } 78 58 79 static __always_inline void irq_work_raise(str << 80 { << 81 if (trace_ipi_send_cpu_enabled() && ar << 82 trace_ipi_send_cpu(smp_process << 83 << 84 arch_irq_work_raise(); << 85 } << 86 << 87 /* Enqueue on current CPU, work must already b 59 /* Enqueue on current CPU, work must already be claimed and preempt disabled */ 88 static void __irq_work_queue_local(struct irq_ 60 static void __irq_work_queue_local(struct irq_work *work) 89 { 61 { 90 struct llist_head *list; << 91 bool rt_lazy_work = false; << 92 bool lazy_work = false; << 93 int work_flags; << 94 << 95 work_flags = atomic_read(&work->node.a << 96 if (work_flags & IRQ_WORK_LAZY) << 97 lazy_work = true; << 98 else if (IS_ENABLED(CONFIG_PREEMPT_RT) << 99 !(work_flags & IRQ_WORK_HARD_ << 100 rt_lazy_work = true; << 101 << 102 if (lazy_work || rt_lazy_work) << 103 list = this_cpu_ptr(&lazy_list << 104 else << 105 list = this_cpu_ptr(&raised_li << 106 << 107 if (!llist_add(&work->node.llist, list << 108 return; << 109 << 110 /* If the work is "lazy", handle it fr 62 /* If the work is "lazy", handle it from next tick if any */ 111 if (!lazy_work || tick_nohz_tick_stopp !! 63 if (work->flags & IRQ_WORK_LAZY) { 112 irq_work_raise(work); !! 64 if (llist_add(&work->llnode, this_cpu_ptr(&lazy_list)) && >> 65 tick_nohz_tick_stopped()) >> 66 arch_irq_work_raise(); >> 67 } else { >> 68 if (llist_add(&work->llnode, this_cpu_ptr(&raised_list))) >> 69 arch_irq_work_raise(); >> 70 } 113 } 71 } 114 72 115 /* Enqueue the irq work @work on the current C 73 /* Enqueue the irq work @work on the current CPU */ 116 bool irq_work_queue(struct irq_work *work) 74 bool irq_work_queue(struct irq_work *work) 117 { 75 { 118 /* Only queue if not already pending * 76 /* Only queue if not already pending */ 119 if (!irq_work_claim(work)) 77 if (!irq_work_claim(work)) 120 return false; 78 return false; 121 79 122 /* Queue the entry and raise the IPI i 80 /* Queue the entry and raise the IPI if needed. */ 123 preempt_disable(); 81 preempt_disable(); 124 __irq_work_queue_local(work); 82 __irq_work_queue_local(work); 125 preempt_enable(); 83 preempt_enable(); 126 84 127 return true; 85 return true; 128 } 86 } 129 EXPORT_SYMBOL_GPL(irq_work_queue); 87 EXPORT_SYMBOL_GPL(irq_work_queue); 130 88 131 /* 89 /* 132 * Enqueue the irq_work @work on @cpu unless i 90 * Enqueue the irq_work @work on @cpu unless it's already pending 133 * somewhere. 91 * somewhere. 134 * 92 * 135 * Can be re-enqueued while the callback is st 93 * Can be re-enqueued while the callback is still in progress. 136 */ 94 */ 137 bool irq_work_queue_on(struct irq_work *work, 95 bool irq_work_queue_on(struct irq_work *work, int cpu) 138 { 96 { 139 #ifndef CONFIG_SMP 97 #ifndef CONFIG_SMP 140 return irq_work_queue(work); 98 return irq_work_queue(work); 141 99 142 #else /* CONFIG_SMP: */ 100 #else /* CONFIG_SMP: */ 143 /* All work should have been flushed b 101 /* All work should have been flushed before going offline */ 144 WARN_ON_ONCE(cpu_is_offline(cpu)); 102 WARN_ON_ONCE(cpu_is_offline(cpu)); 145 103 146 /* Only queue if not already pending * 104 /* Only queue if not already pending */ 147 if (!irq_work_claim(work)) 105 if (!irq_work_claim(work)) 148 return false; 106 return false; 149 107 150 kasan_record_aux_stack_noalloc(work); << 151 << 152 preempt_disable(); 108 preempt_disable(); 153 if (cpu != smp_processor_id()) { 109 if (cpu != smp_processor_id()) { 154 /* Arch remote IPI send/receiv 110 /* Arch remote IPI send/receive backend aren't NMI safe */ 155 WARN_ON_ONCE(in_nmi()); 111 WARN_ON_ONCE(in_nmi()); 156 !! 112 if (llist_add(&work->llnode, &per_cpu(raised_list, cpu))) 157 /* !! 113 arch_send_call_function_single_ipi(cpu); 158 * On PREEMPT_RT the items whi << 159 * IRQ_WORK_HARD_IRQ are added << 160 * item is used on the remote << 161 */ << 162 if (IS_ENABLED(CONFIG_PREEMPT_ << 163 !(atomic_read(&work->node. << 164 << 165 if (!llist_add(&work-> << 166 goto out; << 167 << 168 work = &per_cpu(irq_wo << 169 if (!irq_work_claim(wo << 170 goto out; << 171 } << 172 << 173 __smp_call_single_queue(cpu, & << 174 } else { 114 } else { 175 __irq_work_queue_local(work); 115 __irq_work_queue_local(work); 176 } 116 } 177 out: << 178 preempt_enable(); 117 preempt_enable(); 179 118 180 return true; 119 return true; 181 #endif /* CONFIG_SMP */ 120 #endif /* CONFIG_SMP */ 182 } 121 } 183 122 >> 123 184 bool irq_work_needs_cpu(void) 124 bool irq_work_needs_cpu(void) 185 { 125 { 186 struct llist_head *raised, *lazy; 126 struct llist_head *raised, *lazy; 187 127 188 raised = this_cpu_ptr(&raised_list); 128 raised = this_cpu_ptr(&raised_list); 189 lazy = this_cpu_ptr(&lazy_list); 129 lazy = this_cpu_ptr(&lazy_list); 190 130 191 if (llist_empty(raised) || arch_irq_wo 131 if (llist_empty(raised) || arch_irq_work_has_interrupt()) 192 if (llist_empty(lazy)) 132 if (llist_empty(lazy)) 193 return false; 133 return false; 194 134 195 /* All work should have been flushed b 135 /* All work should have been flushed before going offline */ 196 WARN_ON_ONCE(cpu_is_offline(smp_proces 136 WARN_ON_ONCE(cpu_is_offline(smp_processor_id())); 197 137 198 return true; 138 return true; 199 } 139 } 200 140 201 void irq_work_single(void *arg) << 202 { << 203 struct irq_work *work = arg; << 204 int flags; << 205 << 206 /* << 207 * Clear the PENDING bit, after this p << 208 * The PENDING bit acts as a lock, and << 209 * without atomic ops. << 210 */ << 211 flags = atomic_read(&work->node.a_flag << 212 flags &= ~IRQ_WORK_PENDING; << 213 atomic_set(&work->node.a_flags, flags) << 214 << 215 /* << 216 * See irq_work_claim(). << 217 */ << 218 smp_mb(); << 219 << 220 lockdep_irq_work_enter(flags); << 221 work->func(work); << 222 lockdep_irq_work_exit(flags); << 223 << 224 /* << 225 * Clear the BUSY bit, if set, and ret << 226 * else claimed it meanwhile. << 227 */ << 228 (void)atomic_cmpxchg(&work->node.a_fla << 229 << 230 if ((IS_ENABLED(CONFIG_PREEMPT_RT) && << 231 !arch_irq_work_has_interrupt()) << 232 rcuwait_wake_up(&work->irqwait << 233 } << 234 << 235 static void irq_work_run_list(struct llist_hea 141 static void irq_work_run_list(struct llist_head *list) 236 { 142 { 237 struct irq_work *work, *tmp; 143 struct irq_work *work, *tmp; 238 struct llist_node *llnode; 144 struct llist_node *llnode; >> 145 unsigned long flags; 239 146 240 /* !! 147 BUG_ON(!irqs_disabled()); 241 * On PREEMPT_RT IRQ-work which is not << 242 * in a per-CPU thread in preemptible << 243 * marked as IRQ_WORK_HARD_IRQ will be << 244 */ << 245 BUG_ON(!irqs_disabled() && !IS_ENABLED << 246 148 247 if (llist_empty(list)) 149 if (llist_empty(list)) 248 return; 150 return; 249 151 250 llnode = llist_del_all(list); 152 llnode = llist_del_all(list); 251 llist_for_each_entry_safe(work, tmp, l !! 153 llist_for_each_entry_safe(work, tmp, llnode, llnode) { 252 irq_work_single(work); !! 154 /* >> 155 * Clear the PENDING bit, after this point the @work >> 156 * can be re-used. >> 157 * Make it immediately visible so that other CPUs trying >> 158 * to claim that work don't rely on us to handle their data >> 159 * while we are in the middle of the func. >> 160 */ >> 161 flags = work->flags & ~IRQ_WORK_PENDING; >> 162 xchg(&work->flags, flags); >> 163 >> 164 work->func(work); >> 165 /* >> 166 * Clear the BUSY bit and return to the free state if >> 167 * no-one else claimed it meanwhile. >> 168 */ >> 169 (void)cmpxchg(&work->flags, flags, flags & ~IRQ_WORK_BUSY); >> 170 } 253 } 171 } 254 172 255 /* 173 /* 256 * hotplug calls this through: 174 * hotplug calls this through: 257 * hotplug_cfd() -> flush_smp_call_function_q 175 * hotplug_cfd() -> flush_smp_call_function_queue() 258 */ 176 */ 259 void irq_work_run(void) 177 void irq_work_run(void) 260 { 178 { 261 irq_work_run_list(this_cpu_ptr(&raised 179 irq_work_run_list(this_cpu_ptr(&raised_list)); 262 if (!IS_ENABLED(CONFIG_PREEMPT_RT)) !! 180 irq_work_run_list(this_cpu_ptr(&lazy_list)); 263 irq_work_run_list(this_cpu_ptr << 264 else << 265 wake_irq_workd(); << 266 } 181 } 267 EXPORT_SYMBOL_GPL(irq_work_run); 182 EXPORT_SYMBOL_GPL(irq_work_run); 268 183 269 void irq_work_tick(void) 184 void irq_work_tick(void) 270 { 185 { 271 struct llist_head *raised = this_cpu_p 186 struct llist_head *raised = this_cpu_ptr(&raised_list); 272 187 273 if (!llist_empty(raised) && !arch_irq_ 188 if (!llist_empty(raised) && !arch_irq_work_has_interrupt()) 274 irq_work_run_list(raised); 189 irq_work_run_list(raised); 275 !! 190 irq_work_run_list(this_cpu_ptr(&lazy_list)); 276 if (!IS_ENABLED(CONFIG_PREEMPT_RT)) << 277 irq_work_run_list(this_cpu_ptr << 278 else << 279 wake_irq_workd(); << 280 } 191 } 281 192 282 /* 193 /* 283 * Synchronize against the irq_work @entry, en 194 * Synchronize against the irq_work @entry, ensures the entry is not 284 * currently in use. 195 * currently in use. 285 */ 196 */ 286 void irq_work_sync(struct irq_work *work) 197 void irq_work_sync(struct irq_work *work) 287 { 198 { 288 lockdep_assert_irqs_enabled(); 199 lockdep_assert_irqs_enabled(); 289 might_sleep(); << 290 200 291 if ((IS_ENABLED(CONFIG_PREEMPT_RT) && !! 201 while (work->flags & IRQ_WORK_BUSY) 292 !arch_irq_work_has_interrupt()) { << 293 rcuwait_wait_event(&work->irqw << 294 TASK_UNINTE << 295 return; << 296 } << 297 << 298 while (irq_work_is_busy(work)) << 299 cpu_relax(); 202 cpu_relax(); 300 } 203 } 301 EXPORT_SYMBOL_GPL(irq_work_sync); 204 EXPORT_SYMBOL_GPL(irq_work_sync); 302 << 303 static void run_irq_workd(unsigned int cpu) << 304 { << 305 irq_work_run_list(this_cpu_ptr(&lazy_l << 306 } << 307 << 308 static void irq_workd_setup(unsigned int cpu) << 309 { << 310 sched_set_fifo_low(current); << 311 } << 312 << 313 static struct smp_hotplug_thread irqwork_threa << 314 .store = &irq_workd, << 315 .setup = irq_workd_se << 316 .thread_should_run = irq_workd_sh << 317 .thread_fn = run_irq_work << 318 .thread_comm = "irq_work/%u << 319 }; << 320 << 321 static __init int irq_work_init_threads(void) << 322 { << 323 if (IS_ENABLED(CONFIG_PREEMPT_RT)) << 324 BUG_ON(smpboot_register_percpu << 325 return 0; << 326 } << 327 early_initcall(irq_work_init_threads); << 328 205

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TOMOYO Linux Cross Reference
Linux/kernel/irq_work.c

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Differences between /kernel/irq_work.c (Version linux-6.11.5) and /kernel/irq_work.c (Version linux-5.1.21)

TOMOYO Linux Cross Reference Linux/kernel/irq_work.c

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Differences between /kernel/irq_work.c (Version linux-6.11.5) and /kernel/irq_work.c (Version linux-5.1.21)

TOMOYO Linux Cross Reference
Linux/kernel/irq_work.c