| /* |
| * Read-Copy Update definitions shared among RCU implementations. |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, you can access it online at |
| * http://www.gnu.org/licenses/gpl-2.0.html. |
| * |
| * Copyright IBM Corporation, 2011 |
| * |
| * Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com> |
| */ |
| |
| #ifndef __LINUX_RCU_H |
| #define __LINUX_RCU_H |
| |
| #include <trace/events/rcu.h> |
| #ifdef CONFIG_RCU_TRACE |
| #define RCU_TRACE(stmt) stmt |
| #else /* #ifdef CONFIG_RCU_TRACE */ |
| #define RCU_TRACE(stmt) |
| #endif /* #else #ifdef CONFIG_RCU_TRACE */ |
| |
| /* |
| * Process-level increment to ->dynticks_nesting field. This allows for |
| * architectures that use half-interrupts and half-exceptions from |
| * process context. |
| * |
| * DYNTICK_TASK_NEST_MASK defines a field of width DYNTICK_TASK_NEST_WIDTH |
| * that counts the number of process-based reasons why RCU cannot |
| * consider the corresponding CPU to be idle, and DYNTICK_TASK_NEST_VALUE |
| * is the value used to increment or decrement this field. |
| * |
| * The rest of the bits could in principle be used to count interrupts, |
| * but this would mean that a negative-one value in the interrupt |
| * field could incorrectly zero out the DYNTICK_TASK_NEST_MASK field. |
| * We therefore provide a two-bit guard field defined by DYNTICK_TASK_MASK |
| * that is set to DYNTICK_TASK_FLAG upon initial exit from idle. |
| * The DYNTICK_TASK_EXIT_IDLE value is thus the combined value used upon |
| * initial exit from idle. |
| */ |
| #define DYNTICK_TASK_NEST_WIDTH 7 |
| #define DYNTICK_TASK_NEST_VALUE ((LLONG_MAX >> DYNTICK_TASK_NEST_WIDTH) + 1) |
| #define DYNTICK_TASK_NEST_MASK (LLONG_MAX - DYNTICK_TASK_NEST_VALUE + 1) |
| #define DYNTICK_TASK_FLAG ((DYNTICK_TASK_NEST_VALUE / 8) * 2) |
| #define DYNTICK_TASK_MASK ((DYNTICK_TASK_NEST_VALUE / 8) * 3) |
| #define DYNTICK_TASK_EXIT_IDLE (DYNTICK_TASK_NEST_VALUE + \ |
| DYNTICK_TASK_FLAG) |
| |
| /* |
| * debug_rcu_head_queue()/debug_rcu_head_unqueue() are used internally |
| * by call_rcu() and rcu callback execution, and are therefore not part of the |
| * RCU API. Leaving in rcupdate.h because they are used by all RCU flavors. |
| */ |
| |
| #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD |
| # define STATE_RCU_HEAD_READY 0 |
| # define STATE_RCU_HEAD_QUEUED 1 |
| |
| extern struct debug_obj_descr rcuhead_debug_descr; |
| |
| static inline int debug_rcu_head_queue(struct rcu_head *head) |
| { |
| int r1; |
| |
| r1 = debug_object_activate(head, &rcuhead_debug_descr); |
| debug_object_active_state(head, &rcuhead_debug_descr, |
| STATE_RCU_HEAD_READY, |
| STATE_RCU_HEAD_QUEUED); |
| return r1; |
| } |
| |
| static inline void debug_rcu_head_unqueue(struct rcu_head *head) |
| { |
| debug_object_active_state(head, &rcuhead_debug_descr, |
| STATE_RCU_HEAD_QUEUED, |
| STATE_RCU_HEAD_READY); |
| debug_object_deactivate(head, &rcuhead_debug_descr); |
| } |
| #else /* !CONFIG_DEBUG_OBJECTS_RCU_HEAD */ |
| static inline int debug_rcu_head_queue(struct rcu_head *head) |
| { |
| return 0; |
| } |
| |
| static inline void debug_rcu_head_unqueue(struct rcu_head *head) |
| { |
| } |
| #endif /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */ |
| |
| void kfree(const void *); |
| |
| /* |
| * Reclaim the specified callback, either by invoking it (non-lazy case) |
| * or freeing it directly (lazy case). Return true if lazy, false otherwise. |
| */ |
| static inline bool __rcu_reclaim(const char *rn, struct rcu_head *head) |
| { |
| unsigned long offset = (unsigned long)head->func; |
| |
| rcu_lock_acquire(&rcu_callback_map); |
| if (__is_kfree_rcu_offset(offset)) { |
| RCU_TRACE(trace_rcu_invoke_kfree_callback(rn, head, offset)); |
| kfree((void *)head - offset); |
| rcu_lock_release(&rcu_callback_map); |
| return true; |
| } else { |
| RCU_TRACE(trace_rcu_invoke_callback(rn, head)); |
| head->func(head); |
| rcu_lock_release(&rcu_callback_map); |
| return false; |
| } |
| } |
| |
| #ifdef CONFIG_RCU_STALL_COMMON |
| |
| extern int rcu_cpu_stall_suppress; |
| int rcu_jiffies_till_stall_check(void); |
| |
| #endif /* #ifdef CONFIG_RCU_STALL_COMMON */ |
| |
| /* |
| * Strings used in tracepoints need to be exported via the |
| * tracing system such that tools like perf and trace-cmd can |
| * translate the string address pointers to actual text. |
| */ |
| #define TPS(x) tracepoint_string(x) |
| |
| void rcu_early_boot_tests(void); |
| void rcu_test_sync_prims(void); |
| |
| /* |
| * This function really isn't for public consumption, but RCU is special in |
| * that context switches can allow the state machine to make progress. |
| */ |
| extern void resched_cpu(int cpu); |
| |
| #endif /* __LINUX_RCU_H */ |