1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* interrupt.h */ 3 #ifndef _LINUX_INTERRUPT_H 4 #define _LINUX_INTERRUPT_H 5 6 #include <linux/kernel.h> 7 #include <linux/bitops.h> 8 #include <linux/cleanup.h> 9 #include <linux/irqreturn.h> 10 #include <linux/irqnr.h> 11 #include <linux/hardirq.h> 12 #include <linux/irqflags.h> 13 #include <linux/hrtimer.h> 14 #include <linux/kref.h> 15 #include <linux/cpumask_types.h> 16 #include <linux/workqueue.h> 17 #include <linux/jump_label.h> 18 19 #include <linux/atomic.h> 20 #include <asm/ptrace.h> 21 #include <asm/irq.h> 22 #include <asm/sections.h> 23 24 /* 25 * These correspond to the IORESOURCE_IRQ_* defines in 26 * linux/ioport.h to select the interrupt line behaviour. When 27 * requesting an interrupt without specifying a IRQF_TRIGGER, the 28 * setting should be assumed to be "as already configured", which 29 * may be as per machine or firmware initialisation. 30 */ 31 #define IRQF_TRIGGER_NONE 0x00000000 32 #define IRQF_TRIGGER_RISING 0x00000001 33 #define IRQF_TRIGGER_FALLING 0x00000002 34 #define IRQF_TRIGGER_HIGH 0x00000004 35 #define IRQF_TRIGGER_LOW 0x00000008 36 #define IRQF_TRIGGER_MASK (IRQF_TRIGGER_HIGH | IRQF_TRIGGER_LOW | \ 37 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING) 38 #define IRQF_TRIGGER_PROBE 0x00000010 39 40 /* 41 * These flags used only by the kernel as part of the 42 * irq handling routines. 43 * 44 * IRQF_SHARED - allow sharing the irq among several devices 45 * IRQF_PROBE_SHARED - set by callers when they expect sharing mismatches to occur 46 * IRQF_TIMER - Flag to mark this interrupt as timer interrupt 47 * IRQF_PERCPU - Interrupt is per cpu 48 * IRQF_NOBALANCING - Flag to exclude this interrupt from irq balancing 49 * IRQF_IRQPOLL - Interrupt is used for polling (only the interrupt that is 50 * registered first in a shared interrupt is considered for 51 * performance reasons) 52 * IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler finished. 53 * Used by threaded interrupts which need to keep the 54 * irq line disabled until the threaded handler has been run. 55 * IRQF_NO_SUSPEND - Do not disable this IRQ during suspend. Does not guarantee 56 * that this interrupt will wake the system from a suspended 57 * state. See Documentation/power/suspend-and-interrupts.rst 58 * IRQF_FORCE_RESUME - Force enable it on resume even if IRQF_NO_SUSPEND is set 59 * IRQF_NO_THREAD - Interrupt cannot be threaded 60 * IRQF_EARLY_RESUME - Resume IRQ early during syscore instead of at device 61 * resume time. 62 * IRQF_COND_SUSPEND - If the IRQ is shared with a NO_SUSPEND user, execute this 63 * interrupt handler after suspending interrupts. For system 64 * wakeup devices users need to implement wakeup detection in 65 * their interrupt handlers. 66 * IRQF_NO_AUTOEN - Don't enable IRQ or NMI automatically when users request it. 67 * Users will enable it explicitly by enable_irq() or enable_nmi() 68 * later. 69 * IRQF_NO_DEBUG - Exclude from runnaway detection for IPI and similar handlers, 70 * depends on IRQF_PERCPU. 71 * IRQF_COND_ONESHOT - Agree to do IRQF_ONESHOT if already set for a shared 72 * interrupt. 73 */ 74 #define IRQF_SHARED 0x00000080 75 #define IRQF_PROBE_SHARED 0x00000100 76 #define __IRQF_TIMER 0x00000200 77 #define IRQF_PERCPU 0x00000400 78 #define IRQF_NOBALANCING 0x00000800 79 #define IRQF_IRQPOLL 0x00001000 80 #define IRQF_ONESHOT 0x00002000 81 #define IRQF_NO_SUSPEND 0x00004000 82 #define IRQF_FORCE_RESUME 0x00008000 83 #define IRQF_NO_THREAD 0x00010000 84 #define IRQF_EARLY_RESUME 0x00020000 85 #define IRQF_COND_SUSPEND 0x00040000 86 #define IRQF_NO_AUTOEN 0x00080000 87 #define IRQF_NO_DEBUG 0x00100000 88 #define IRQF_COND_ONESHOT 0x00200000 89 90 #define IRQF_TIMER (__IRQF_TIMER | IRQF_NO_SUSPEND | IRQF_NO_THREAD) 91 92 /* 93 * These values can be returned by request_any_context_irq() and 94 * describe the context the interrupt will be run in. 95 * 96 * IRQC_IS_HARDIRQ - interrupt runs in hardirq context 97 * IRQC_IS_NESTED - interrupt runs in a nested threaded context 98 */ 99 enum { 100 IRQC_IS_HARDIRQ = 0, 101 IRQC_IS_NESTED, 102 }; 103 104 typedef irqreturn_t (*irq_handler_t)(int, void *); 105 106 /** 107 * struct irqaction - per interrupt action descriptor 108 * @handler: interrupt handler function 109 * @name: name of the device 110 * @dev_id: cookie to identify the device 111 * @percpu_dev_id: cookie to identify the device 112 * @affinity: CPUs this irqaction is allowed to run on 113 * @next: pointer to the next irqaction for shared interrupts 114 * @irq: interrupt number 115 * @flags: flags (see IRQF_* above) 116 * @thread_fn: interrupt handler function for threaded interrupts 117 * @thread: thread pointer for threaded interrupts 118 * @secondary: pointer to secondary irqaction (force threading) 119 * @thread_flags: flags related to @thread 120 * @thread_mask: bitmask for keeping track of @thread activity 121 * @dir: pointer to the proc/irq/NN/name entry 122 */ 123 struct irqaction { 124 irq_handler_t handler; 125 union { 126 void *dev_id; 127 void __percpu *percpu_dev_id; 128 }; 129 const struct cpumask *affinity; 130 struct irqaction *next; 131 irq_handler_t thread_fn; 132 struct task_struct *thread; 133 struct irqaction *secondary; 134 unsigned int irq; 135 unsigned int flags; 136 unsigned long thread_flags; 137 unsigned long thread_mask; 138 const char *name; 139 struct proc_dir_entry *dir; 140 } ____cacheline_internodealigned_in_smp; 141 142 extern irqreturn_t no_action(int cpl, void *dev_id); 143 144 /* 145 * If a (PCI) device interrupt is not connected we set dev->irq to 146 * IRQ_NOTCONNECTED. This causes request_irq() to fail with -ENOTCONN, so we 147 * can distinguish that case from other error returns. 148 * 149 * 0x80000000 is guaranteed to be outside the available range of interrupts 150 * and easy to distinguish from other possible incorrect values. 151 */ 152 #define IRQ_NOTCONNECTED (1U << 31) 153 154 extern int __must_check 155 request_threaded_irq(unsigned int irq, irq_handler_t handler, 156 irq_handler_t thread_fn, 157 unsigned long flags, const char *name, void *dev); 158 159 /** 160 * request_irq - Add a handler for an interrupt line 161 * @irq: The interrupt line to allocate 162 * @handler: Function to be called when the IRQ occurs. 163 * Primary handler for threaded interrupts 164 * If NULL, the default primary handler is installed 165 * @flags: Handling flags 166 * @name: Name of the device generating this interrupt 167 * @dev: A cookie passed to the handler function 168 * 169 * This call allocates an interrupt and establishes a handler; see 170 * the documentation for request_threaded_irq() for details. 171 */ 172 static inline int __must_check 173 request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags, 174 const char *name, void *dev) 175 { 176 return request_threaded_irq(irq, handler, NULL, flags | IRQF_COND_ONESHOT, name, dev); 177 } 178 179 extern int __must_check 180 request_any_context_irq(unsigned int irq, irq_handler_t handler, 181 unsigned long flags, const char *name, void *dev_id); 182 183 extern int __must_check 184 request_percpu_irq_affinity(unsigned int irq, irq_handler_t handler, const char *devname, 185 const cpumask_t *affinity, void __percpu *percpu_dev_id); 186 187 extern int __must_check 188 request_nmi(unsigned int irq, irq_handler_t handler, unsigned long flags, 189 const char *name, void *dev); 190 191 static inline int __must_check 192 request_percpu_irq(unsigned int irq, irq_handler_t handler, 193 const char *devname, void __percpu *percpu_dev_id) 194 { 195 return request_percpu_irq_affinity(irq, handler, devname, 196 NULL, percpu_dev_id); 197 } 198 199 extern int __must_check 200 request_percpu_nmi(unsigned int irq, irq_handler_t handler, const char *name, 201 const struct cpumask *affinity, void __percpu *dev_id); 202 203 extern const void *free_irq(unsigned int, void *); 204 extern void free_percpu_irq(unsigned int, void __percpu *); 205 206 extern const void *free_nmi(unsigned int irq, void *dev_id); 207 extern void free_percpu_nmi(unsigned int irq, void __percpu *percpu_dev_id); 208 209 struct device; 210 211 extern int __must_check 212 devm_request_threaded_irq(struct device *dev, unsigned int irq, 213 irq_handler_t handler, irq_handler_t thread_fn, 214 unsigned long irqflags, const char *devname, 215 void *dev_id); 216 217 static inline int __must_check 218 devm_request_irq(struct device *dev, unsigned int irq, irq_handler_t handler, 219 unsigned long irqflags, const char *devname, void *dev_id) 220 { 221 return devm_request_threaded_irq(dev, irq, handler, NULL, irqflags | IRQF_COND_ONESHOT, 222 devname, dev_id); 223 } 224 225 extern int __must_check 226 devm_request_any_context_irq(struct device *dev, unsigned int irq, 227 irq_handler_t handler, unsigned long irqflags, 228 const char *devname, void *dev_id); 229 230 extern void devm_free_irq(struct device *dev, unsigned int irq, void *dev_id); 231 232 bool irq_has_action(unsigned int irq); 233 extern void disable_irq_nosync(unsigned int irq); 234 extern bool disable_hardirq(unsigned int irq); 235 extern void disable_irq(unsigned int irq); 236 extern void disable_percpu_irq(unsigned int irq); 237 extern void enable_irq(unsigned int irq); 238 extern void enable_percpu_irq(unsigned int irq, unsigned int type); 239 extern bool irq_percpu_is_enabled(unsigned int irq); 240 extern void irq_wake_thread(unsigned int irq, void *dev_id); 241 242 DEFINE_LOCK_GUARD_1(disable_irq, int, 243 disable_irq(*_T->lock), enable_irq(*_T->lock)) 244 245 extern void disable_nmi_nosync(unsigned int irq); 246 extern void disable_percpu_nmi(unsigned int irq); 247 extern void enable_nmi(unsigned int irq); 248 extern void enable_percpu_nmi(unsigned int irq, unsigned int type); 249 extern int prepare_percpu_nmi(unsigned int irq); 250 extern void teardown_percpu_nmi(unsigned int irq); 251 252 extern int irq_inject_interrupt(unsigned int irq); 253 254 /* The following three functions are for the core kernel use only. */ 255 extern void suspend_device_irqs(void); 256 extern void resume_device_irqs(void); 257 extern void rearm_wake_irq(unsigned int irq); 258 259 /** 260 * struct irq_affinity_notify - context for notification of IRQ affinity changes 261 * @irq: Interrupt to which notification applies 262 * @kref: Reference count, for internal use 263 * @work: Work item, for internal use 264 * @notify: Function to be called on change. This will be 265 * called in process context. 266 * @release: Function to be called on release. This will be 267 * called in process context. Once registered, the 268 * structure must only be freed when this function is 269 * called or later. 270 */ 271 struct irq_affinity_notify { 272 unsigned int irq; 273 struct kref kref; 274 struct work_struct work; 275 void (*notify)(struct irq_affinity_notify *, const cpumask_t *mask); 276 void (*release)(struct kref *ref); 277 }; 278 279 #define IRQ_AFFINITY_MAX_SETS 4 280 281 /** 282 * struct irq_affinity - Description for automatic irq affinity assignments 283 * @pre_vectors: Don't apply affinity to @pre_vectors at beginning of 284 * the MSI(-X) vector space 285 * @post_vectors: Don't apply affinity to @post_vectors at end of 286 * the MSI(-X) vector space 287 * @nr_sets: The number of interrupt sets for which affinity 288 * spreading is required 289 * @set_size: Array holding the size of each interrupt set 290 * @calc_sets: Callback for calculating the number and size 291 * of interrupt sets 292 * @priv: Private data for usage by @calc_sets, usually a 293 * pointer to driver/device specific data. 294 */ 295 struct irq_affinity { 296 unsigned int pre_vectors; 297 unsigned int post_vectors; 298 unsigned int nr_sets; 299 unsigned int set_size[IRQ_AFFINITY_MAX_SETS]; 300 void (*calc_sets)(struct irq_affinity *, unsigned int nvecs); 301 void *priv; 302 }; 303 304 /** 305 * struct irq_affinity_desc - Interrupt affinity descriptor 306 * @mask: cpumask to hold the affinity assignment 307 * @is_managed: 1 if the interrupt is managed internally 308 */ 309 struct irq_affinity_desc { 310 struct cpumask mask; 311 unsigned int is_managed : 1; 312 }; 313 314 #if defined(CONFIG_SMP) 315 316 extern cpumask_var_t irq_default_affinity; 317 318 extern int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask); 319 extern int irq_force_affinity(unsigned int irq, const struct cpumask *cpumask); 320 321 extern int irq_can_set_affinity(unsigned int irq); 322 extern int irq_select_affinity(unsigned int irq); 323 324 extern int __irq_apply_affinity_hint(unsigned int irq, const struct cpumask *m, 325 bool setaffinity); 326 327 /** 328 * irq_update_affinity_hint - Update the affinity hint 329 * @irq: Interrupt to update 330 * @m: cpumask pointer (NULL to clear the hint) 331 * 332 * Updates the affinity hint, but does not change the affinity of the interrupt. 333 */ 334 static inline int 335 irq_update_affinity_hint(unsigned int irq, const struct cpumask *m) 336 { 337 return __irq_apply_affinity_hint(irq, m, false); 338 } 339 340 /** 341 * irq_set_affinity_and_hint - Update the affinity hint and apply the provided 342 * cpumask to the interrupt 343 * @irq: Interrupt to update 344 * @m: cpumask pointer (NULL to clear the hint) 345 * 346 * Updates the affinity hint and if @m is not NULL it applies it as the 347 * affinity of that interrupt. 348 */ 349 static inline int 350 irq_set_affinity_and_hint(unsigned int irq, const struct cpumask *m) 351 { 352 return __irq_apply_affinity_hint(irq, m, true); 353 } 354 355 /* 356 * Deprecated. Use irq_update_affinity_hint() or irq_set_affinity_and_hint() 357 * instead. 358 */ 359 static inline int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m) 360 { 361 return irq_set_affinity_and_hint(irq, m); 362 } 363 364 extern int irq_update_affinity_desc(unsigned int irq, 365 struct irq_affinity_desc *affinity); 366 367 extern int 368 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify); 369 370 struct irq_affinity_desc * 371 irq_create_affinity_masks(unsigned int nvec, struct irq_affinity *affd); 372 373 unsigned int irq_calc_affinity_vectors(unsigned int minvec, unsigned int maxvec, 374 const struct irq_affinity *affd); 375 376 #else /* CONFIG_SMP */ 377 378 static inline int irq_set_affinity(unsigned int irq, const struct cpumask *m) 379 { 380 return -EINVAL; 381 } 382 383 static inline int irq_force_affinity(unsigned int irq, const struct cpumask *cpumask) 384 { 385 return 0; 386 } 387 388 static inline int irq_can_set_affinity(unsigned int irq) 389 { 390 return 0; 391 } 392 393 static inline int irq_select_affinity(unsigned int irq) { return 0; } 394 395 static inline int irq_update_affinity_hint(unsigned int irq, 396 const struct cpumask *m) 397 { 398 return -EINVAL; 399 } 400 401 static inline int irq_set_affinity_and_hint(unsigned int irq, 402 const struct cpumask *m) 403 { 404 return -EINVAL; 405 } 406 407 static inline int irq_set_affinity_hint(unsigned int irq, 408 const struct cpumask *m) 409 { 410 return -EINVAL; 411 } 412 413 static inline int irq_update_affinity_desc(unsigned int irq, 414 struct irq_affinity_desc *affinity) 415 { 416 return -EINVAL; 417 } 418 419 static inline int 420 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify) 421 { 422 return 0; 423 } 424 425 static inline struct irq_affinity_desc * 426 irq_create_affinity_masks(unsigned int nvec, struct irq_affinity *affd) 427 { 428 return NULL; 429 } 430 431 static inline unsigned int 432 irq_calc_affinity_vectors(unsigned int minvec, unsigned int maxvec, 433 const struct irq_affinity *affd) 434 { 435 return maxvec; 436 } 437 438 #endif /* CONFIG_SMP */ 439 440 /* 441 * Special lockdep variants of irq disabling/enabling. 442 * These should be used for locking constructs that 443 * know that a particular irq context which is disabled, 444 * and which is the only irq-context user of a lock, 445 * that it's safe to take the lock in the irq-disabled 446 * section without disabling hardirqs. 447 * 448 * On !CONFIG_LOCKDEP they are equivalent to the normal 449 * irq disable/enable methods. 450 */ 451 static inline void disable_irq_nosync_lockdep(unsigned int irq) 452 { 453 disable_irq_nosync(irq); 454 #if defined(CONFIG_LOCKDEP) && !defined(CONFIG_PREEMPT_RT) 455 local_irq_disable(); 456 #endif 457 } 458 459 static inline void disable_irq_nosync_lockdep_irqsave(unsigned int irq, unsigned long *flags) 460 { 461 disable_irq_nosync(irq); 462 #if defined(CONFIG_LOCKDEP) && !defined(CONFIG_PREEMPT_RT) 463 local_irq_save(*flags); 464 #endif 465 } 466 467 static inline void enable_irq_lockdep(unsigned int irq) 468 { 469 #if defined(CONFIG_LOCKDEP) && !defined(CONFIG_PREEMPT_RT) 470 local_irq_enable(); 471 #endif 472 enable_irq(irq); 473 } 474 475 static inline void enable_irq_lockdep_irqrestore(unsigned int irq, unsigned long *flags) 476 { 477 #if defined(CONFIG_LOCKDEP) && !defined(CONFIG_PREEMPT_RT) 478 local_irq_restore(*flags); 479 #endif 480 enable_irq(irq); 481 } 482 483 /* IRQ wakeup (PM) control: */ 484 extern int irq_set_irq_wake(unsigned int irq, unsigned int on); 485 486 static inline int enable_irq_wake(unsigned int irq) 487 { 488 return irq_set_irq_wake(irq, 1); 489 } 490 491 static inline int disable_irq_wake(unsigned int irq) 492 { 493 return irq_set_irq_wake(irq, 0); 494 } 495 496 /* 497 * irq_get_irqchip_state/irq_set_irqchip_state specific flags 498 */ 499 enum irqchip_irq_state { 500 IRQCHIP_STATE_PENDING, /* Is interrupt pending? */ 501 IRQCHIP_STATE_ACTIVE, /* Is interrupt in progress? */ 502 IRQCHIP_STATE_MASKED, /* Is interrupt masked? */ 503 IRQCHIP_STATE_LINE_LEVEL, /* Is IRQ line high? */ 504 }; 505 506 extern int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which, 507 bool *state); 508 extern int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which, 509 bool state); 510 511 #ifdef CONFIG_IRQ_FORCED_THREADING 512 # ifdef CONFIG_PREEMPT_RT 513 # define force_irqthreads() (true) 514 # else 515 DECLARE_STATIC_KEY_FALSE(force_irqthreads_key); 516 # define force_irqthreads() (static_branch_unlikely(&force_irqthreads_key)) 517 # endif 518 #else 519 #define force_irqthreads() (false) 520 #endif 521 522 #ifndef local_softirq_pending 523 524 #ifndef local_softirq_pending_ref 525 #define local_softirq_pending_ref irq_stat.__softirq_pending 526 #endif 527 528 #define local_softirq_pending() (__this_cpu_read(local_softirq_pending_ref)) 529 #define set_softirq_pending(x) (__this_cpu_write(local_softirq_pending_ref, (x))) 530 #define or_softirq_pending(x) (__this_cpu_or(local_softirq_pending_ref, (x))) 531 532 #endif /* local_softirq_pending */ 533 534 /* Some architectures might implement lazy enabling/disabling of 535 * interrupts. In some cases, such as stop_machine, we might want 536 * to ensure that after a local_irq_disable(), interrupts have 537 * really been disabled in hardware. Such architectures need to 538 * implement the following hook. 539 */ 540 #ifndef hard_irq_disable 541 #define hard_irq_disable() do { } while(0) 542 #endif 543 544 /* PLEASE, avoid to allocate new softirqs, if you need not _really_ high 545 frequency threaded job scheduling. For almost all the purposes 546 tasklets are more than enough. F.e. all serial device BHs et 547 al. should be converted to tasklets, not to softirqs. 548 */ 549 550 enum 551 { 552 HI_SOFTIRQ=0, 553 TIMER_SOFTIRQ, 554 NET_TX_SOFTIRQ, 555 NET_RX_SOFTIRQ, 556 BLOCK_SOFTIRQ, 557 IRQ_POLL_SOFTIRQ, 558 TASKLET_SOFTIRQ, 559 SCHED_SOFTIRQ, 560 HRTIMER_SOFTIRQ, 561 RCU_SOFTIRQ, /* Preferable RCU should always be the last softirq */ 562 563 NR_SOFTIRQS 564 }; 565 566 /* 567 * The following vectors can be safely ignored after ksoftirqd is parked: 568 * 569 * _ RCU: 570 * 1) rcutree_migrate_callbacks() migrates the queue. 571 * 2) rcutree_report_cpu_dead() reports the final quiescent states. 572 * 573 * _ IRQ_POLL: irq_poll_cpu_dead() migrates the queue 574 * 575 * _ (HR)TIMER_SOFTIRQ: (hr)timers_dead_cpu() migrates the queue 576 */ 577 #define SOFTIRQ_HOTPLUG_SAFE_MASK (BIT(TIMER_SOFTIRQ) | BIT(IRQ_POLL_SOFTIRQ) |\ 578 BIT(HRTIMER_SOFTIRQ) | BIT(RCU_SOFTIRQ)) 579 580 581 /* map softirq index to softirq name. update 'softirq_to_name' in 582 * kernel/softirq.c when adding a new softirq. 583 */ 584 extern const char * const softirq_to_name[NR_SOFTIRQS]; 585 586 /* softirq mask and active fields moved to irq_cpustat_t in 587 * asm/hardirq.h to get better cache usage. KAO 588 */ 589 590 struct softirq_action 591 { 592 void (*action)(void); 593 }; 594 595 asmlinkage void do_softirq(void); 596 asmlinkage void __do_softirq(void); 597 598 #ifdef CONFIG_PREEMPT_RT 599 extern void do_softirq_post_smp_call_flush(unsigned int was_pending); 600 #else 601 static inline void do_softirq_post_smp_call_flush(unsigned int unused) 602 { 603 do_softirq(); 604 } 605 #endif 606 607 extern void open_softirq(int nr, void (*action)(void)); 608 extern void softirq_init(void); 609 extern void __raise_softirq_irqoff(unsigned int nr); 610 611 extern void raise_softirq_irqoff(unsigned int nr); 612 extern void raise_softirq(unsigned int nr); 613 614 /* 615 * With forced-threaded interrupts enabled a raised softirq is deferred to 616 * ksoftirqd unless it can be handled within the threaded interrupt. This 617 * affects timer_list timers and hrtimers which are explicitly marked with 618 * HRTIMER_MODE_SOFT. 619 * With PREEMPT_RT enabled more hrtimers are moved to softirq for processing 620 * which includes all timers which are not explicitly marked HRTIMER_MODE_HARD. 621 * Userspace controlled timers (like the clock_nanosleep() interface) is divided 622 * into two categories: Tasks with elevated scheduling policy including 623 * SCHED_{FIFO|RR|DL} and the remaining scheduling policy. The tasks with the 624 * elevated scheduling policy are woken up directly from the HARDIRQ while all 625 * other wake ups are delayed to softirq and so to ksoftirqd. 626 * 627 * The ksoftirqd runs at SCHED_OTHER policy at which it should remain since it 628 * handles the softirq in an overloaded situation (not handled everything 629 * within its last run). 630 * If the timers are handled at SCHED_OTHER priority then they competes with all 631 * other SCHED_OTHER tasks for CPU resources are possibly delayed. 632 * Moving timers softirqs to a low priority SCHED_FIFO thread instead ensures 633 * that timer are performed before scheduling any SCHED_OTHER thread. 634 */ 635 DECLARE_PER_CPU(struct task_struct *, ktimerd); 636 DECLARE_PER_CPU(unsigned long, pending_timer_softirq); 637 void raise_ktimers_thread(unsigned int nr); 638 639 static inline unsigned int local_timers_pending_force_th(void) 640 { 641 return __this_cpu_read(pending_timer_softirq); 642 } 643 644 static inline void raise_timer_softirq(unsigned int nr) 645 { 646 lockdep_assert_in_irq(); 647 if (force_irqthreads()) 648 raise_ktimers_thread(nr); 649 else 650 __raise_softirq_irqoff(nr); 651 } 652 653 static inline unsigned int local_timers_pending(void) 654 { 655 if (force_irqthreads()) 656 return local_timers_pending_force_th(); 657 else 658 return local_softirq_pending(); 659 } 660 661 DECLARE_PER_CPU(struct task_struct *, ksoftirqd); 662 663 static inline struct task_struct *this_cpu_ksoftirqd(void) 664 { 665 return this_cpu_read(ksoftirqd); 666 } 667 668 /* Tasklets --- multithreaded analogue of BHs. 669 670 This API is deprecated. Please consider using threaded IRQs instead: 671 https://lore.kernel.org/lkml/20200716081538.2sivhkj4hcyrusem@linutronix.de 672 673 Main feature differing them of generic softirqs: tasklet 674 is running only on one CPU simultaneously. 675 676 Main feature differing them of BHs: different tasklets 677 may be run simultaneously on different CPUs. 678 679 Properties: 680 * If tasklet_schedule() is called, then tasklet is guaranteed 681 to be executed on some cpu at least once after this. 682 * If the tasklet is already scheduled, but its execution is still not 683 started, it will be executed only once. 684 * If this tasklet is already running on another CPU (or schedule is called 685 from tasklet itself), it is rescheduled for later. 686 * Tasklet is strictly serialized wrt itself, but not 687 wrt another tasklets. If client needs some intertask synchronization, 688 he makes it with spinlocks. 689 */ 690 691 struct tasklet_struct 692 { 693 struct tasklet_struct *next; 694 unsigned long state; 695 atomic_t count; 696 bool use_callback; 697 union { 698 void (*func)(unsigned long data); 699 void (*callback)(struct tasklet_struct *t); 700 }; 701 unsigned long data; 702 }; 703 704 #define DECLARE_TASKLET(name, _callback) \ 705 struct tasklet_struct name = { \ 706 .count = ATOMIC_INIT(0), \ 707 .callback = _callback, \ 708 .use_callback = true, \ 709 } 710 711 #define DECLARE_TASKLET_DISABLED(name, _callback) \ 712 struct tasklet_struct name = { \ 713 .count = ATOMIC_INIT(1), \ 714 .callback = _callback, \ 715 .use_callback = true, \ 716 } 717 718 #define from_tasklet(var, callback_tasklet, tasklet_fieldname) \ 719 container_of(callback_tasklet, typeof(*var), tasklet_fieldname) 720 721 #define DECLARE_TASKLET_OLD(name, _func) \ 722 struct tasklet_struct name = { \ 723 .count = ATOMIC_INIT(0), \ 724 .func = _func, \ 725 } 726 727 #define DECLARE_TASKLET_DISABLED_OLD(name, _func) \ 728 struct tasklet_struct name = { \ 729 .count = ATOMIC_INIT(1), \ 730 .func = _func, \ 731 } 732 733 enum 734 { 735 TASKLET_STATE_SCHED, /* Tasklet is scheduled for execution */ 736 TASKLET_STATE_RUN /* Tasklet is running (SMP only) */ 737 }; 738 739 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT) 740 static inline int tasklet_trylock(struct tasklet_struct *t) 741 { 742 return !test_and_set_bit(TASKLET_STATE_RUN, &(t)->state); 743 } 744 745 void tasklet_unlock(struct tasklet_struct *t); 746 void tasklet_unlock_wait(struct tasklet_struct *t); 747 void tasklet_unlock_spin_wait(struct tasklet_struct *t); 748 749 #else 750 static inline int tasklet_trylock(struct tasklet_struct *t) { return 1; } 751 static inline void tasklet_unlock(struct tasklet_struct *t) { } 752 static inline void tasklet_unlock_wait(struct tasklet_struct *t) { } 753 static inline void tasklet_unlock_spin_wait(struct tasklet_struct *t) { } 754 #endif 755 756 extern void __tasklet_schedule(struct tasklet_struct *t); 757 758 static inline void tasklet_schedule(struct tasklet_struct *t) 759 { 760 if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) 761 __tasklet_schedule(t); 762 } 763 764 extern void __tasklet_hi_schedule(struct tasklet_struct *t); 765 766 static inline void tasklet_hi_schedule(struct tasklet_struct *t) 767 { 768 if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) 769 __tasklet_hi_schedule(t); 770 } 771 772 static inline void tasklet_disable_nosync(struct tasklet_struct *t) 773 { 774 atomic_inc(&t->count); 775 smp_mb__after_atomic(); 776 } 777 778 /* 779 * Do not use in new code. Disabling tasklets from atomic contexts is 780 * error prone and should be avoided. 781 */ 782 static inline void tasklet_disable_in_atomic(struct tasklet_struct *t) 783 { 784 tasklet_disable_nosync(t); 785 tasklet_unlock_spin_wait(t); 786 smp_mb(); 787 } 788 789 static inline void tasklet_disable(struct tasklet_struct *t) 790 { 791 tasklet_disable_nosync(t); 792 tasklet_unlock_wait(t); 793 smp_mb(); 794 } 795 796 static inline void tasklet_enable(struct tasklet_struct *t) 797 { 798 smp_mb__before_atomic(); 799 atomic_dec(&t->count); 800 } 801 802 extern void tasklet_kill(struct tasklet_struct *t); 803 extern void tasklet_init(struct tasklet_struct *t, 804 void (*func)(unsigned long), unsigned long data); 805 extern void tasklet_setup(struct tasklet_struct *t, 806 void (*callback)(struct tasklet_struct *)); 807 808 /* 809 * Autoprobing for irqs: 810 * 811 * probe_irq_on() and probe_irq_off() provide robust primitives 812 * for accurate IRQ probing during kernel initialization. They are 813 * reasonably simple to use, are not "fooled" by spurious interrupts, 814 * and, unlike other attempts at IRQ probing, they do not get hung on 815 * stuck interrupts (such as unused PS2 mouse interfaces on ASUS boards). 816 * 817 * For reasonably foolproof probing, use them as follows: 818 * 819 * 1. clear and/or mask the device's internal interrupt. 820 * 2. sti(); 821 * 3. irqs = probe_irq_on(); // "take over" all unassigned idle IRQs 822 * 4. enable the device and cause it to trigger an interrupt. 823 * 5. wait for the device to interrupt, using non-intrusive polling or a delay. 824 * 6. irq = probe_irq_off(irqs); // get IRQ number, 0=none, negative=multiple 825 * 7. service the device to clear its pending interrupt. 826 * 8. loop again if paranoia is required. 827 * 828 * probe_irq_on() returns a mask of allocated irq's. 829 * 830 * probe_irq_off() takes the mask as a parameter, 831 * and returns the irq number which occurred, 832 * or zero if none occurred, or a negative irq number 833 * if more than one irq occurred. 834 */ 835 836 #if !defined(CONFIG_GENERIC_IRQ_PROBE) 837 static inline unsigned long probe_irq_on(void) 838 { 839 return 0; 840 } 841 static inline int probe_irq_off(unsigned long val) 842 { 843 return 0; 844 } 845 static inline unsigned int probe_irq_mask(unsigned long val) 846 { 847 return 0; 848 } 849 #else 850 extern unsigned long probe_irq_on(void); /* returns 0 on failure */ 851 extern int probe_irq_off(unsigned long); /* returns 0 or negative on failure */ 852 extern unsigned int probe_irq_mask(unsigned long); /* returns mask of ISA interrupts */ 853 #endif 854 855 #ifdef CONFIG_PROC_FS 856 /* Initialize /proc/irq/ */ 857 extern void init_irq_proc(void); 858 #else 859 static inline void init_irq_proc(void) 860 { 861 } 862 #endif 863 864 struct seq_file; 865 int show_interrupts(struct seq_file *p, void *v); 866 int arch_show_interrupts(struct seq_file *p, int prec); 867 868 extern int early_irq_init(void); 869 extern int arch_probe_nr_irqs(void); 870 extern int arch_early_irq_init(void); 871 872 /* 873 * We want to know which function is an entrypoint of a hardirq or a softirq. 874 */ 875 #ifndef __irq_entry 876 # define __irq_entry __section(".irqentry.text") 877 #endif 878 879 #define __softirq_entry __section(".softirqentry.text") 880 881 #endif 882