| // SPDX-License-Identifier: GPL-2.0+ |
| /* |
| * Read-Copy Update mechanism for mutual exclusion |
| * |
| * Copyright IBM Corporation, 2001 |
| * |
| * Authors: Dipankar Sarma <dipankar@in.ibm.com> |
| * Manfred Spraul <manfred@colorfullife.com> |
| * |
| * Based on the original work by Paul McKenney <paulmck@linux.ibm.com> |
| * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen. |
| * Papers: |
| * http://www.rdrop.com/users/paulmck/paper/rclockpdcsproof.pdf |
| * http://lse.sourceforge.net/locking/rclock_OLS.2001.05.01c.sc.pdf (OLS2001) |
| * |
| * For detailed explanation of Read-Copy Update mechanism see - |
| * http://lse.sourceforge.net/locking/rcupdate.html |
| * |
| */ |
| #include <linux/types.h> |
| #include <linux/kernel.h> |
| #include <linux/init.h> |
| #include <linux/spinlock.h> |
| #include <linux/smp.h> |
| #include <linux/interrupt.h> |
| #include <linux/sched/signal.h> |
| #include <linux/sched/debug.h> |
| #include <linux/atomic.h> |
| #include <linux/bitops.h> |
| #include <linux/percpu.h> |
| #include <linux/notifier.h> |
| #include <linux/cpu.h> |
| #include <linux/mutex.h> |
| #include <linux/export.h> |
| #include <linux/hardirq.h> |
| #include <linux/delay.h> |
| #include <linux/moduleparam.h> |
| #include <linux/kthread.h> |
| #include <linux/tick.h> |
| #include <linux/rcupdate_wait.h> |
| #include <linux/sched/isolation.h> |
| #include <linux/kprobes.h> |
| #include <linux/slab.h> |
| #include <linux/irq_work.h> |
| #include <linux/rcupdate_trace.h> |
| #include <linux/jiffies.h> |
| |
| #define CREATE_TRACE_POINTS |
| |
| #include "rcu.h" |
| |
| #ifdef MODULE_PARAM_PREFIX |
| #undef MODULE_PARAM_PREFIX |
| #endif |
| #define MODULE_PARAM_PREFIX "rcupdate." |
| |
| #ifndef CONFIG_TINY_RCU |
| module_param(rcu_expedited, int, 0444); |
| module_param(rcu_normal, int, 0444); |
| static int rcu_normal_after_boot = IS_ENABLED(CONFIG_PREEMPT_RT); |
| #if !defined(CONFIG_PREEMPT_RT) || defined(CONFIG_NO_HZ_FULL) |
| module_param(rcu_normal_after_boot, int, 0444); |
| #endif |
| #endif /* #ifndef CONFIG_TINY_RCU */ |
| |
| #ifdef CONFIG_DEBUG_LOCK_ALLOC |
| /** |
| * rcu_read_lock_held_common() - might we be in RCU-sched read-side critical section? |
| * @ret: Best guess answer if lockdep cannot be relied on |
| * |
| * Returns true if lockdep must be ignored, in which case ``*ret`` contains |
| * the best guess described below. Otherwise returns false, in which |
| * case ``*ret`` tells the caller nothing and the caller should instead |
| * consult lockdep. |
| * |
| * If CONFIG_DEBUG_LOCK_ALLOC is selected, set ``*ret`` to nonzero iff in an |
| * RCU-sched read-side critical section. In absence of |
| * CONFIG_DEBUG_LOCK_ALLOC, this assumes we are in an RCU-sched read-side |
| * critical section unless it can prove otherwise. Note that disabling |
| * of preemption (including disabling irqs) counts as an RCU-sched |
| * read-side critical section. This is useful for debug checks in functions |
| * that required that they be called within an RCU-sched read-side |
| * critical section. |
| * |
| * Check debug_lockdep_rcu_enabled() to prevent false positives during boot |
| * and while lockdep is disabled. |
| * |
| * Note that if the CPU is in the idle loop from an RCU point of view (ie: |
| * that we are in the section between ct_idle_enter() and ct_idle_exit()) |
| * then rcu_read_lock_held() sets ``*ret`` to false even if the CPU did an |
| * rcu_read_lock(). The reason for this is that RCU ignores CPUs that are |
| * in such a section, considering these as in extended quiescent state, |
| * so such a CPU is effectively never in an RCU read-side critical section |
| * regardless of what RCU primitives it invokes. This state of affairs is |
| * required --- we need to keep an RCU-free window in idle where the CPU may |
| * possibly enter into low power mode. This way we can notice an extended |
| * quiescent state to other CPUs that started a grace period. Otherwise |
| * we would delay any grace period as long as we run in the idle task. |
| * |
| * Similarly, we avoid claiming an RCU read lock held if the current |
| * CPU is offline. |
| */ |
| static bool rcu_read_lock_held_common(bool *ret) |
| { |
| if (!debug_lockdep_rcu_enabled()) { |
| *ret = true; |
| return true; |
| } |
| if (!rcu_is_watching()) { |
| *ret = false; |
| return true; |
| } |
| if (!rcu_lockdep_current_cpu_online()) { |
| *ret = false; |
| return true; |
| } |
| return false; |
| } |
| |
| int rcu_read_lock_sched_held(void) |
| { |
| bool ret; |
| |
| if (rcu_read_lock_held_common(&ret)) |
| return ret; |
| return lock_is_held(&rcu_sched_lock_map) || !preemptible(); |
| } |
| EXPORT_SYMBOL(rcu_read_lock_sched_held); |
| #endif |
| |
| #ifndef CONFIG_TINY_RCU |
| |
| /* |
| * Should expedited grace-period primitives always fall back to their |
| * non-expedited counterparts? Intended for use within RCU. Note |
| * that if the user specifies both rcu_expedited and rcu_normal, then |
| * rcu_normal wins. (Except during the time period during boot from |
| * when the first task is spawned until the rcu_set_runtime_mode() |
| * core_initcall() is invoked, at which point everything is expedited.) |
| */ |
| bool rcu_gp_is_normal(void) |
| { |
| return READ_ONCE(rcu_normal) && |
| rcu_scheduler_active != RCU_SCHEDULER_INIT; |
| } |
| EXPORT_SYMBOL_GPL(rcu_gp_is_normal); |
| |
| static atomic_t rcu_async_hurry_nesting = ATOMIC_INIT(1); |
| /* |
| * Should call_rcu() callbacks be processed with urgency or are |
| * they OK being executed with arbitrary delays? |
| */ |
| bool rcu_async_should_hurry(void) |
| { |
| return !IS_ENABLED(CONFIG_RCU_LAZY) || |
| atomic_read(&rcu_async_hurry_nesting); |
| } |
| EXPORT_SYMBOL_GPL(rcu_async_should_hurry); |
| |
| /** |
| * rcu_async_hurry - Make future async RCU callbacks not lazy. |
| * |
| * After a call to this function, future calls to call_rcu() |
| * will be processed in a timely fashion. |
| */ |
| void rcu_async_hurry(void) |
| { |
| if (IS_ENABLED(CONFIG_RCU_LAZY)) |
| atomic_inc(&rcu_async_hurry_nesting); |
| } |
| EXPORT_SYMBOL_GPL(rcu_async_hurry); |
| |
| /** |
| * rcu_async_relax - Make future async RCU callbacks lazy. |
| * |
| * After a call to this function, future calls to call_rcu() |
| * will be processed in a lazy fashion. |
| */ |
| void rcu_async_relax(void) |
| { |
| if (IS_ENABLED(CONFIG_RCU_LAZY)) |
| atomic_dec(&rcu_async_hurry_nesting); |
| } |
| EXPORT_SYMBOL_GPL(rcu_async_relax); |
| |
| static atomic_t rcu_expedited_nesting = ATOMIC_INIT(1); |
| /* |
| * Should normal grace-period primitives be expedited? Intended for |
| * use within RCU. Note that this function takes the rcu_expedited |
| * sysfs/boot variable and rcu_scheduler_active into account as well |
| * as the rcu_expedite_gp() nesting. So looping on rcu_unexpedite_gp() |
| * until rcu_gp_is_expedited() returns false is a -really- bad idea. |
| */ |
| bool rcu_gp_is_expedited(void) |
| { |
| return rcu_expedited || atomic_read(&rcu_expedited_nesting); |
| } |
| EXPORT_SYMBOL_GPL(rcu_gp_is_expedited); |
| |
| /** |
| * rcu_expedite_gp - Expedite future RCU grace periods |
| * |
| * After a call to this function, future calls to synchronize_rcu() and |
| * friends act as the corresponding synchronize_rcu_expedited() function |
| * had instead been called. |
| */ |
| void rcu_expedite_gp(void) |
| { |
| atomic_inc(&rcu_expedited_nesting); |
| } |
| EXPORT_SYMBOL_GPL(rcu_expedite_gp); |
| |
| /** |
| * rcu_unexpedite_gp - Cancel prior rcu_expedite_gp() invocation |
| * |
| * Undo a prior call to rcu_expedite_gp(). If all prior calls to |
| * rcu_expedite_gp() are undone by a subsequent call to rcu_unexpedite_gp(), |
| * and if the rcu_expedited sysfs/boot parameter is not set, then all |
| * subsequent calls to synchronize_rcu() and friends will return to |
| * their normal non-expedited behavior. |
| */ |
| void rcu_unexpedite_gp(void) |
| { |
| atomic_dec(&rcu_expedited_nesting); |
| } |
| EXPORT_SYMBOL_GPL(rcu_unexpedite_gp); |
| |
| /* |
| * Minimum time in milliseconds from the start boot until RCU can consider |
| * in-kernel boot as completed. This can also be tuned at runtime to end the |
| * boot earlier, by userspace init code writing the time in milliseconds (even |
| * 0) to: /sys/module/rcupdate/parameters/rcu_boot_end_delay. The sysfs node |
| * can also be used to extend the delay to be larger than the default, assuming |
| * the marking of boot complete has not yet occurred. |
| */ |
| static int rcu_boot_end_delay = CONFIG_RCU_BOOT_END_DELAY; |
| |
| static bool rcu_boot_ended __read_mostly; |
| static bool rcu_boot_end_called __read_mostly; |
| static DEFINE_MUTEX(rcu_boot_end_lock); |
| |
| /* |
| * Inform RCU of the end of the in-kernel boot sequence. The boot sequence will |
| * not be marked ended until at least rcu_boot_end_delay milliseconds have passed. |
| */ |
| void rcu_end_inkernel_boot(void); |
| static void rcu_boot_end_work_fn(struct work_struct *work) |
| { |
| rcu_end_inkernel_boot(); |
| } |
| static DECLARE_DELAYED_WORK(rcu_boot_end_work, rcu_boot_end_work_fn); |
| |
| /* Must be called with rcu_boot_end_lock held. */ |
| static void rcu_end_inkernel_boot_locked(void) |
| { |
| rcu_boot_end_called = true; |
| |
| if (rcu_boot_ended) |
| return; |
| |
| if (rcu_boot_end_delay) { |
| u64 boot_ms = div_u64(ktime_get_boot_fast_ns(), 1000000UL); |
| |
| if (boot_ms < rcu_boot_end_delay) { |
| schedule_delayed_work(&rcu_boot_end_work, |
| msecs_to_jiffies(rcu_boot_end_delay - boot_ms)); |
| return; |
| } |
| } |
| |
| cancel_delayed_work(&rcu_boot_end_work); |
| rcu_unexpedite_gp(); |
| rcu_async_relax(); |
| if (rcu_normal_after_boot) |
| WRITE_ONCE(rcu_normal, 1); |
| rcu_boot_ended = true; |
| } |
| |
| void rcu_end_inkernel_boot(void) |
| { |
| mutex_lock(&rcu_boot_end_lock); |
| rcu_end_inkernel_boot_locked(); |
| mutex_unlock(&rcu_boot_end_lock); |
| } |
| |
| static int param_set_rcu_boot_end(const char *val, const struct kernel_param *kp) |
| { |
| uint end_ms; |
| int ret = kstrtouint(val, 0, &end_ms); |
| |
| if (ret) |
| return ret; |
| /* |
| * rcu_end_inkernel_boot() should be called at least once during init |
| * before we can allow param changes to end the boot. |
| */ |
| mutex_lock(&rcu_boot_end_lock); |
| rcu_boot_end_delay = end_ms; |
| if (!rcu_boot_ended && rcu_boot_end_called) { |
| rcu_end_inkernel_boot_locked(); |
| } |
| mutex_unlock(&rcu_boot_end_lock); |
| return ret; |
| } |
| |
| static const struct kernel_param_ops rcu_boot_end_ops = { |
| .set = param_set_rcu_boot_end, |
| .get = param_get_uint, |
| }; |
| module_param_cb(rcu_boot_end_delay, &rcu_boot_end_ops, &rcu_boot_end_delay, 0644); |
| |
| /* |
| * Let rcutorture know when it is OK to turn it up to eleven. |
| */ |
| bool rcu_inkernel_boot_has_ended(void) |
| { |
| return rcu_boot_ended; |
| } |
| EXPORT_SYMBOL_GPL(rcu_inkernel_boot_has_ended); |
| |
| #endif /* #ifndef CONFIG_TINY_RCU */ |
| |
| /* |
| * Test each non-SRCU synchronous grace-period wait API. This is |
| * useful just after a change in mode for these primitives, and |
| * during early boot. |
| */ |
| void rcu_test_sync_prims(void) |
| { |
| if (!IS_ENABLED(CONFIG_PROVE_RCU)) |
| return; |
| pr_info("Running RCU synchronous self tests\n"); |
| synchronize_rcu(); |
| synchronize_rcu_expedited(); |
| } |
| |
| #if !defined(CONFIG_TINY_RCU) |
| |
| /* |
| * Switch to run-time mode once RCU has fully initialized. |
| */ |
| static int __init rcu_set_runtime_mode(void) |
| { |
| rcu_test_sync_prims(); |
| rcu_scheduler_active = RCU_SCHEDULER_RUNNING; |
| kfree_rcu_scheduler_running(); |
| rcu_test_sync_prims(); |
| return 0; |
| } |
| core_initcall(rcu_set_runtime_mode); |
| |
| #endif /* #if !defined(CONFIG_TINY_RCU) */ |
| |
| #ifdef CONFIG_DEBUG_LOCK_ALLOC |
| static struct lock_class_key rcu_lock_key; |
| struct lockdep_map rcu_lock_map = { |
| .name = "rcu_read_lock", |
| .key = &rcu_lock_key, |
| .wait_type_outer = LD_WAIT_FREE, |
| .wait_type_inner = LD_WAIT_CONFIG, /* PREEMPT_RT implies PREEMPT_RCU */ |
| }; |
| EXPORT_SYMBOL_GPL(rcu_lock_map); |
| |
| static struct lock_class_key rcu_bh_lock_key; |
| struct lockdep_map rcu_bh_lock_map = { |
| .name = "rcu_read_lock_bh", |
| .key = &rcu_bh_lock_key, |
| .wait_type_outer = LD_WAIT_FREE, |
| .wait_type_inner = LD_WAIT_CONFIG, /* PREEMPT_RT makes BH preemptible. */ |
| }; |
| EXPORT_SYMBOL_GPL(rcu_bh_lock_map); |
| |
| static struct lock_class_key rcu_sched_lock_key; |
| struct lockdep_map rcu_sched_lock_map = { |
| .name = "rcu_read_lock_sched", |
| .key = &rcu_sched_lock_key, |
| .wait_type_outer = LD_WAIT_FREE, |
| .wait_type_inner = LD_WAIT_SPIN, |
| }; |
| EXPORT_SYMBOL_GPL(rcu_sched_lock_map); |
| |
| // Tell lockdep when RCU callbacks are being invoked. |
| static struct lock_class_key rcu_callback_key; |
| struct lockdep_map rcu_callback_map = |
| STATIC_LOCKDEP_MAP_INIT("rcu_callback", &rcu_callback_key); |
| EXPORT_SYMBOL_GPL(rcu_callback_map); |
| |
| noinstr int notrace debug_lockdep_rcu_enabled(void) |
| { |
| return rcu_scheduler_active != RCU_SCHEDULER_INACTIVE && READ_ONCE(debug_locks) && |
| current->lockdep_recursion == 0; |
| } |
| EXPORT_SYMBOL_GPL(debug_lockdep_rcu_enabled); |
| |
| /** |
| * rcu_read_lock_held() - might we be in RCU read-side critical section? |
| * |
| * If CONFIG_DEBUG_LOCK_ALLOC is selected, returns nonzero iff in an RCU |
| * read-side critical section. In absence of CONFIG_DEBUG_LOCK_ALLOC, |
| * this assumes we are in an RCU read-side critical section unless it can |
| * prove otherwise. This is useful for debug checks in functions that |
| * require that they be called within an RCU read-side critical section. |
| * |
| * Checks debug_lockdep_rcu_enabled() to prevent false positives during boot |
| * and while lockdep is disabled. |
| * |
| * Note that rcu_read_lock() and the matching rcu_read_unlock() must |
| * occur in the same context, for example, it is illegal to invoke |
| * rcu_read_unlock() in process context if the matching rcu_read_lock() |
| * was invoked from within an irq handler. |
| * |
| * Note that rcu_read_lock() is disallowed if the CPU is either idle or |
| * offline from an RCU perspective, so check for those as well. |
| */ |
| int rcu_read_lock_held(void) |
| { |
| bool ret; |
| |
| if (rcu_read_lock_held_common(&ret)) |
| return ret; |
| return lock_is_held(&rcu_lock_map); |
| } |
| EXPORT_SYMBOL_GPL(rcu_read_lock_held); |
| |
| /** |
| * rcu_read_lock_bh_held() - might we be in RCU-bh read-side critical section? |
| * |
| * Check for bottom half being disabled, which covers both the |
| * CONFIG_PROVE_RCU and not cases. Note that if someone uses |
| * rcu_read_lock_bh(), but then later enables BH, lockdep (if enabled) |
| * will show the situation. This is useful for debug checks in functions |
| * that require that they be called within an RCU read-side critical |
| * section. |
| * |
| * Check debug_lockdep_rcu_enabled() to prevent false positives during boot. |
| * |
| * Note that rcu_read_lock_bh() is disallowed if the CPU is either idle or |
| * offline from an RCU perspective, so check for those as well. |
| */ |
| int rcu_read_lock_bh_held(void) |
| { |
| bool ret; |
| |
| if (rcu_read_lock_held_common(&ret)) |
| return ret; |
| return in_softirq() || irqs_disabled(); |
| } |
| EXPORT_SYMBOL_GPL(rcu_read_lock_bh_held); |
| |
| int rcu_read_lock_any_held(void) |
| { |
| bool ret; |
| |
| if (rcu_read_lock_held_common(&ret)) |
| return ret; |
| if (lock_is_held(&rcu_lock_map) || |
| lock_is_held(&rcu_bh_lock_map) || |
| lock_is_held(&rcu_sched_lock_map)) |
| return 1; |
| return !preemptible(); |
| } |
| EXPORT_SYMBOL_GPL(rcu_read_lock_any_held); |
| |
| #endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ |
| |
| /** |
| * wakeme_after_rcu() - Callback function to awaken a task after grace period |
| * @head: Pointer to rcu_head member within rcu_synchronize structure |
| * |
| * Awaken the corresponding task now that a grace period has elapsed. |
| */ |
| void wakeme_after_rcu(struct rcu_head *head) |
| { |
| struct rcu_synchronize *rcu; |
| |
| rcu = container_of(head, struct rcu_synchronize, head); |
| complete(&rcu->completion); |
| } |
| EXPORT_SYMBOL_GPL(wakeme_after_rcu); |
| |
| void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array, |
| struct rcu_synchronize *rs_array) |
| { |
| int i; |
| int j; |
| |
| /* Initialize and register callbacks for each crcu_array element. */ |
| for (i = 0; i < n; i++) { |
| if (checktiny && |
| (crcu_array[i] == call_rcu)) { |
| might_sleep(); |
| continue; |
| } |
| for (j = 0; j < i; j++) |
| if (crcu_array[j] == crcu_array[i]) |
| break; |
| if (j == i) { |
| init_rcu_head_on_stack(&rs_array[i].head); |
| init_completion(&rs_array[i].completion); |
| (crcu_array[i])(&rs_array[i].head, wakeme_after_rcu); |
| } |
| } |
| |
| /* Wait for all callbacks to be invoked. */ |
| for (i = 0; i < n; i++) { |
| if (checktiny && |
| (crcu_array[i] == call_rcu)) |
| continue; |
| for (j = 0; j < i; j++) |
| if (crcu_array[j] == crcu_array[i]) |
| break; |
| if (j == i) { |
| wait_for_completion(&rs_array[i].completion); |
| destroy_rcu_head_on_stack(&rs_array[i].head); |
| } |
| } |
| } |
| EXPORT_SYMBOL_GPL(__wait_rcu_gp); |
| |
| void finish_rcuwait(struct rcuwait *w) |
| { |
| rcu_assign_pointer(w->task, NULL); |
| __set_current_state(TASK_RUNNING); |
| } |
| EXPORT_SYMBOL_GPL(finish_rcuwait); |
| |
| #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD |
| void init_rcu_head(struct rcu_head *head) |
| { |
| debug_object_init(head, &rcuhead_debug_descr); |
| } |
| EXPORT_SYMBOL_GPL(init_rcu_head); |
| |
| void destroy_rcu_head(struct rcu_head *head) |
| { |
| debug_object_free(head, &rcuhead_debug_descr); |
| } |
| EXPORT_SYMBOL_GPL(destroy_rcu_head); |
| |
| static bool rcuhead_is_static_object(void *addr) |
| { |
| return true; |
| } |
| |
| /** |
| * init_rcu_head_on_stack() - initialize on-stack rcu_head for debugobjects |
| * @head: pointer to rcu_head structure to be initialized |
| * |
| * This function informs debugobjects of a new rcu_head structure that |
| * has been allocated as an auto variable on the stack. This function |
| * is not required for rcu_head structures that are statically defined or |
| * that are dynamically allocated on the heap. This function has no |
| * effect for !CONFIG_DEBUG_OBJECTS_RCU_HEAD kernel builds. |
| */ |
| void init_rcu_head_on_stack(struct rcu_head *head) |
| { |
| debug_object_init_on_stack(head, &rcuhead_debug_descr); |
| } |
| EXPORT_SYMBOL_GPL(init_rcu_head_on_stack); |
| |
| /** |
| * destroy_rcu_head_on_stack() - destroy on-stack rcu_head for debugobjects |
| * @head: pointer to rcu_head structure to be initialized |
| * |
| * This function informs debugobjects that an on-stack rcu_head structure |
| * is about to go out of scope. As with init_rcu_head_on_stack(), this |
| * function is not required for rcu_head structures that are statically |
| * defined or that are dynamically allocated on the heap. Also as with |
| * init_rcu_head_on_stack(), this function has no effect for |
| * !CONFIG_DEBUG_OBJECTS_RCU_HEAD kernel builds. |
| */ |
| void destroy_rcu_head_on_stack(struct rcu_head *head) |
| { |
| debug_object_free(head, &rcuhead_debug_descr); |
| } |
| EXPORT_SYMBOL_GPL(destroy_rcu_head_on_stack); |
| |
| const struct debug_obj_descr rcuhead_debug_descr = { |
| .name = "rcu_head", |
| .is_static_object = rcuhead_is_static_object, |
| }; |
| EXPORT_SYMBOL_GPL(rcuhead_debug_descr); |
| #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ |
| |
| #if defined(CONFIG_TREE_RCU) || defined(CONFIG_RCU_TRACE) |
| void do_trace_rcu_torture_read(const char *rcutorturename, struct rcu_head *rhp, |
| unsigned long secs, |
| unsigned long c_old, unsigned long c) |
| { |
| trace_rcu_torture_read(rcutorturename, rhp, secs, c_old, c); |
| } |
| EXPORT_SYMBOL_GPL(do_trace_rcu_torture_read); |
| #else |
| #define do_trace_rcu_torture_read(rcutorturename, rhp, secs, c_old, c) \ |
| do { } while (0) |
| #endif |
| |
| #if IS_ENABLED(CONFIG_RCU_TORTURE_TEST) || IS_MODULE(CONFIG_RCU_TORTURE_TEST) |
| /* Get rcutorture access to sched_setaffinity(). */ |
| long rcutorture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask) |
| { |
| int ret; |
| |
| ret = sched_setaffinity(pid, in_mask); |
| WARN_ONCE(ret, "%s: sched_setaffinity() returned %d\n", __func__, ret); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(rcutorture_sched_setaffinity); |
| #endif |
| |
| #ifdef CONFIG_RCU_STALL_COMMON |
| int rcu_cpu_stall_ftrace_dump __read_mostly; |
| module_param(rcu_cpu_stall_ftrace_dump, int, 0644); |
| int rcu_cpu_stall_suppress __read_mostly; // !0 = suppress stall warnings. |
| EXPORT_SYMBOL_GPL(rcu_cpu_stall_suppress); |
| module_param(rcu_cpu_stall_suppress, int, 0644); |
| int rcu_cpu_stall_timeout __read_mostly = CONFIG_RCU_CPU_STALL_TIMEOUT; |
| module_param(rcu_cpu_stall_timeout, int, 0644); |
| int rcu_exp_cpu_stall_timeout __read_mostly = CONFIG_RCU_EXP_CPU_STALL_TIMEOUT; |
| module_param(rcu_exp_cpu_stall_timeout, int, 0644); |
| int rcu_cpu_stall_cputime __read_mostly = IS_ENABLED(CONFIG_RCU_CPU_STALL_CPUTIME); |
| module_param(rcu_cpu_stall_cputime, int, 0644); |
| bool rcu_exp_stall_task_details __read_mostly; |
| module_param(rcu_exp_stall_task_details, bool, 0644); |
| #endif /* #ifdef CONFIG_RCU_STALL_COMMON */ |
| |
| // Suppress boot-time RCU CPU stall warnings and rcutorture writer stall |
| // warnings. Also used by rcutorture even if stall warnings are excluded. |
| int rcu_cpu_stall_suppress_at_boot __read_mostly; // !0 = suppress boot stalls. |
| EXPORT_SYMBOL_GPL(rcu_cpu_stall_suppress_at_boot); |
| module_param(rcu_cpu_stall_suppress_at_boot, int, 0444); |
| |
| /** |
| * get_completed_synchronize_rcu - Return a pre-completed polled state cookie |
| * |
| * Returns a value that will always be treated by functions like |
| * poll_state_synchronize_rcu() as a cookie whose grace period has already |
| * completed. |
| */ |
| unsigned long get_completed_synchronize_rcu(void) |
| { |
| return RCU_GET_STATE_COMPLETED; |
| } |
| EXPORT_SYMBOL_GPL(get_completed_synchronize_rcu); |
| |
| #ifdef CONFIG_PROVE_RCU |
| |
| /* |
| * Early boot self test parameters. |
| */ |
| static bool rcu_self_test; |
| module_param(rcu_self_test, bool, 0444); |
| |
| static int rcu_self_test_counter; |
| |
| static void test_callback(struct rcu_head *r) |
| { |
| rcu_self_test_counter++; |
| pr_info("RCU test callback executed %d\n", rcu_self_test_counter); |
| } |
| |
| DEFINE_STATIC_SRCU(early_srcu); |
| static unsigned long early_srcu_cookie; |
| |
| struct early_boot_kfree_rcu { |
| struct rcu_head rh; |
| }; |
| |
| static void early_boot_test_call_rcu(void) |
| { |
| static struct rcu_head head; |
| int idx; |
| static struct rcu_head shead; |
| struct early_boot_kfree_rcu *rhp; |
| |
| idx = srcu_down_read(&early_srcu); |
| srcu_up_read(&early_srcu, idx); |
| call_rcu(&head, test_callback); |
| early_srcu_cookie = start_poll_synchronize_srcu(&early_srcu); |
| call_srcu(&early_srcu, &shead, test_callback); |
| rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); |
| if (!WARN_ON_ONCE(!rhp)) |
| kfree_rcu(rhp, rh); |
| } |
| |
| void rcu_early_boot_tests(void) |
| { |
| pr_info("Running RCU self tests\n"); |
| |
| if (rcu_self_test) |
| early_boot_test_call_rcu(); |
| rcu_test_sync_prims(); |
| } |
| |
| static int rcu_verify_early_boot_tests(void) |
| { |
| int ret = 0; |
| int early_boot_test_counter = 0; |
| |
| if (rcu_self_test) { |
| early_boot_test_counter++; |
| rcu_barrier(); |
| early_boot_test_counter++; |
| srcu_barrier(&early_srcu); |
| WARN_ON_ONCE(!poll_state_synchronize_srcu(&early_srcu, early_srcu_cookie)); |
| cleanup_srcu_struct(&early_srcu); |
| } |
| if (rcu_self_test_counter != early_boot_test_counter) { |
| WARN_ON(1); |
| ret = -1; |
| } |
| |
| return ret; |
| } |
| late_initcall(rcu_verify_early_boot_tests); |
| #else |
| void rcu_early_boot_tests(void) {} |
| #endif /* CONFIG_PROVE_RCU */ |
| |
| #include "tasks.h" |
| |
| #ifndef CONFIG_TINY_RCU |
| |
| /* |
| * Print any significant non-default boot-time settings. |
| */ |
| void __init rcupdate_announce_bootup_oddness(void) |
| { |
| if (rcu_normal) |
| pr_info("\tNo expedited grace period (rcu_normal).\n"); |
| else if (rcu_normal_after_boot) |
| pr_info("\tNo expedited grace period (rcu_normal_after_boot).\n"); |
| else if (rcu_expedited) |
| pr_info("\tAll grace periods are expedited (rcu_expedited).\n"); |
| if (rcu_cpu_stall_suppress) |
| pr_info("\tRCU CPU stall warnings suppressed (rcu_cpu_stall_suppress).\n"); |
| if (rcu_cpu_stall_timeout != CONFIG_RCU_CPU_STALL_TIMEOUT) |
| pr_info("\tRCU CPU stall warnings timeout set to %d (rcu_cpu_stall_timeout).\n", rcu_cpu_stall_timeout); |
| rcu_tasks_bootup_oddness(); |
| } |
| |
| #endif /* #ifndef CONFIG_TINY_RCU */ |