/*************************************************************************** * Copyright (c) 2024 Microsoft Corporation * * This program and the accompanying materials are made available under the * terms of the MIT License which is available at * https://opensource.org/licenses/MIT. * * SPDX-License-Identifier: MIT **************************************************************************/ /**************************************************************************/ /**************************************************************************/ /** */ /** ThreadX Component */ /** */ /** Mutex */ /** */ /**************************************************************************/ /**************************************************************************/ #define TX_SOURCE_CODE /* Include necessary system files. */ #include "tx_api.h" #include "tx_trace.h" #include "tx_thread.h" #include "tx_mutex.h" /**************************************************************************/ /* */ /* FUNCTION RELEASE */ /* */ /* _tx_mutex_get PORTABLE C */ /* 6.1 */ /* AUTHOR */ /* */ /* William E. Lamie, Microsoft Corporation */ /* */ /* DESCRIPTION */ /* */ /* This function gets the specified mutex. If the calling thread */ /* already owns the mutex, an ownership count is simply increased. */ /* */ /* INPUT */ /* */ /* mutex_ptr Pointer to mutex control block */ /* wait_option Suspension option */ /* */ /* OUTPUT */ /* */ /* status Completion status */ /* */ /* CALLS */ /* */ /* _tx_thread_system_suspend Suspend thread service */ /* _tx_thread_system_ni_suspend Non-interruptable suspend thread */ /* _tx_mutex_priority_change Inherit thread priority */ /* */ /* CALLED BY */ /* */ /* Application Code */ /* */ /* RELEASE HISTORY */ /* */ /* DATE NAME DESCRIPTION */ /* */ /* 05-19-2020 William E. Lamie Initial Version 6.0 */ /* 09-30-2020 Yuxin Zhou Modified comment(s), */ /* resulting in version 6.1 */ /* */ /**************************************************************************/ UINT _tx_mutex_get(TX_MUTEX *mutex_ptr, ULONG wait_option) { TX_INTERRUPT_SAVE_AREA TX_THREAD *thread_ptr; TX_MUTEX *next_mutex; TX_MUTEX *previous_mutex; TX_THREAD *mutex_owner; TX_THREAD *next_thread; TX_THREAD *previous_thread; UINT status; /* Disable interrupts to get an instance from the mutex. */ TX_DISABLE #ifdef TX_MUTEX_ENABLE_PERFORMANCE_INFO /* Increment the total mutex get counter. */ _tx_mutex_performance_get_count++; /* Increment the number of attempts to get this mutex. */ mutex_ptr -> tx_mutex_performance_get_count++; #endif /* If trace is enabled, insert this event into the trace buffer. */ TX_TRACE_IN_LINE_INSERT(TX_TRACE_MUTEX_GET, mutex_ptr, wait_option, TX_POINTER_TO_ULONG_CONVERT(mutex_ptr -> tx_mutex_owner), mutex_ptr -> tx_mutex_ownership_count, TX_TRACE_MUTEX_EVENTS) /* Log this kernel call. */ TX_EL_MUTEX_GET_INSERT /* Pickup thread pointer. */ TX_THREAD_GET_CURRENT(thread_ptr) /* Determine if this mutex is available. */ if (mutex_ptr -> tx_mutex_ownership_count == ((UINT) 0)) { /* Set the ownership count to 1. */ mutex_ptr -> tx_mutex_ownership_count = ((UINT) 1); /* Remember that the calling thread owns the mutex. */ mutex_ptr -> tx_mutex_owner = thread_ptr; /* Determine if the thread pointer is valid. */ if (thread_ptr != TX_NULL) { /* Determine if priority inheritance is required. */ if (mutex_ptr -> tx_mutex_inherit == TX_TRUE) { /* Remember the current priority of thread. */ mutex_ptr -> tx_mutex_original_priority = thread_ptr -> tx_thread_priority; /* Setup the highest priority waiting thread. */ mutex_ptr -> tx_mutex_highest_priority_waiting = ((UINT) TX_MAX_PRIORITIES); } /* Pickup next mutex pointer, which is the head of the list. */ next_mutex = thread_ptr -> tx_thread_owned_mutex_list; /* Determine if this thread owns any other mutexes that have priority inheritance. */ if (next_mutex != TX_NULL) { /* Non-empty list. Link up the mutex. */ /* Pickup the next and previous mutex pointer. */ previous_mutex = next_mutex -> tx_mutex_owned_previous; /* Place the owned mutex in the list. */ next_mutex -> tx_mutex_owned_previous = mutex_ptr; previous_mutex -> tx_mutex_owned_next = mutex_ptr; /* Setup this mutex's next and previous created links. */ mutex_ptr -> tx_mutex_owned_previous = previous_mutex; mutex_ptr -> tx_mutex_owned_next = next_mutex; } else { /* The owned mutex list is empty. Add mutex to empty list. */ thread_ptr -> tx_thread_owned_mutex_list = mutex_ptr; mutex_ptr -> tx_mutex_owned_next = mutex_ptr; mutex_ptr -> tx_mutex_owned_previous = mutex_ptr; } /* Increment the number of mutexes owned counter. */ thread_ptr -> tx_thread_owned_mutex_count++; } /* Restore interrupts. */ TX_RESTORE /* Return success. */ status = TX_SUCCESS; } /* Otherwise, see if the owning thread is trying to obtain the same mutex. */ else if (mutex_ptr -> tx_mutex_owner == thread_ptr) { /* The owning thread is requesting the mutex again, just increment the ownership count. */ mutex_ptr -> tx_mutex_ownership_count++; /* Restore interrupts. */ TX_RESTORE /* Return success. */ status = TX_SUCCESS; } else { /* Determine if the request specifies suspension. */ if (wait_option != TX_NO_WAIT) { /* Determine if the preempt disable flag is non-zero. */ if (_tx_thread_preempt_disable != ((UINT) 0)) { /* Restore interrupts. */ TX_RESTORE /* Suspension is not allowed if the preempt disable flag is non-zero at this point - return error completion. */ status = TX_NOT_AVAILABLE; } else { /* Prepare for suspension of this thread. */ /* Pickup the mutex owner. */ mutex_owner = mutex_ptr -> tx_mutex_owner; #ifdef TX_MUTEX_ENABLE_PERFORMANCE_INFO /* Increment the total mutex suspension counter. */ _tx_mutex_performance_suspension_count++; /* Increment the number of suspensions on this mutex. */ mutex_ptr -> tx_mutex_performance_suspension_count++; /* Determine if a priority inversion is present. */ if (thread_ptr -> tx_thread_priority < mutex_owner -> tx_thread_priority) { /* Yes, priority inversion is present! */ /* Increment the total mutex priority inversions counter. */ _tx_mutex_performance_priority_inversion_count++; /* Increment the number of priority inversions on this mutex. */ mutex_ptr -> tx_mutex_performance_priority_inversion_count++; #ifdef TX_THREAD_ENABLE_PERFORMANCE_INFO /* Increment the number of total thread priority inversions. */ _tx_thread_performance_priority_inversion_count++; /* Increment the number of priority inversions for this thread. */ thread_ptr -> tx_thread_performance_priority_inversion_count++; #endif } #endif /* Setup cleanup routine pointer. */ thread_ptr -> tx_thread_suspend_cleanup = &(_tx_mutex_cleanup); /* Setup cleanup information, i.e. this mutex control block. */ thread_ptr -> tx_thread_suspend_control_block = (VOID *) mutex_ptr; #ifndef TX_NOT_INTERRUPTABLE /* Increment the suspension sequence number, which is used to identify this suspension event. */ thread_ptr -> tx_thread_suspension_sequence++; #endif /* Setup suspension list. */ if (mutex_ptr -> tx_mutex_suspended_count == TX_NO_SUSPENSIONS) { /* No other threads are suspended. Setup the head pointer and just setup this threads pointers to itself. */ mutex_ptr -> tx_mutex_suspension_list = thread_ptr; thread_ptr -> tx_thread_suspended_next = thread_ptr; thread_ptr -> tx_thread_suspended_previous = thread_ptr; } else { /* This list is not NULL, add current thread to the end. */ next_thread = mutex_ptr -> tx_mutex_suspension_list; thread_ptr -> tx_thread_suspended_next = next_thread; previous_thread = next_thread -> tx_thread_suspended_previous; thread_ptr -> tx_thread_suspended_previous = previous_thread; previous_thread -> tx_thread_suspended_next = thread_ptr; next_thread -> tx_thread_suspended_previous = thread_ptr; } /* Increment the suspension count. */ mutex_ptr -> tx_mutex_suspended_count++; /* Set the state to suspended. */ thread_ptr -> tx_thread_state = TX_MUTEX_SUSP; #ifdef TX_NOT_INTERRUPTABLE /* Determine if we need to raise the priority of the thread owning the mutex. */ if (mutex_ptr -> tx_mutex_inherit == TX_TRUE) { /* Determine if this is the highest priority to raise for this mutex. */ if (mutex_ptr -> tx_mutex_highest_priority_waiting > thread_ptr -> tx_thread_priority) { /* Remember this priority. */ mutex_ptr -> tx_mutex_highest_priority_waiting = thread_ptr -> tx_thread_priority; } /* Determine if we have to update inherit priority level of the mutex owner. */ if (thread_ptr -> tx_thread_priority < mutex_owner -> tx_thread_inherit_priority) { /* Remember the new priority inheritance priority. */ mutex_owner -> tx_thread_inherit_priority = thread_ptr -> tx_thread_priority; } /* Priority inheritance is requested, check to see if the thread that owns the mutex is lower priority. */ if (mutex_owner -> tx_thread_priority > thread_ptr -> tx_thread_priority) { /* Yes, raise the suspended, owning thread's priority to that of the current thread. */ _tx_mutex_priority_change(mutex_owner, thread_ptr -> tx_thread_priority); #ifdef TX_MUTEX_ENABLE_PERFORMANCE_INFO /* Increment the total mutex priority inheritance counter. */ _tx_mutex_performance__priority_inheritance_count++; /* Increment the number of priority inheritance situations on this mutex. */ mutex_ptr -> tx_mutex_performance__priority_inheritance_count++; #endif } } /* Call actual non-interruptable thread suspension routine. */ _tx_thread_system_ni_suspend(thread_ptr, wait_option); /* Restore interrupts. */ TX_RESTORE #else /* Set the suspending flag. */ thread_ptr -> tx_thread_suspending = TX_TRUE; /* Setup the timeout period. */ thread_ptr -> tx_thread_timer.tx_timer_internal_remaining_ticks = wait_option; /* Temporarily disable preemption. */ _tx_thread_preempt_disable++; /* Restore interrupts. */ TX_RESTORE /* Determine if we need to raise the priority of the thread owning the mutex. */ if (mutex_ptr -> tx_mutex_inherit == TX_TRUE) { /* Determine if this is the highest priority to raise for this mutex. */ if (mutex_ptr -> tx_mutex_highest_priority_waiting > thread_ptr -> tx_thread_priority) { /* Remember this priority. */ mutex_ptr -> tx_mutex_highest_priority_waiting = thread_ptr -> tx_thread_priority; } /* Determine if we have to update inherit priority level of the mutex owner. */ if (thread_ptr -> tx_thread_priority < mutex_owner -> tx_thread_inherit_priority) { /* Remember the new priority inheritance priority. */ mutex_owner -> tx_thread_inherit_priority = thread_ptr -> tx_thread_priority; } /* Priority inheritance is requested, check to see if the thread that owns the mutex is lower priority. */ if (mutex_owner -> tx_thread_priority > thread_ptr -> tx_thread_priority) { /* Yes, raise the suspended, owning thread's priority to that of the current thread. */ _tx_mutex_priority_change(mutex_owner, thread_ptr -> tx_thread_priority); #ifdef TX_MUTEX_ENABLE_PERFORMANCE_INFO /* Increment the total mutex priority inheritance counter. */ _tx_mutex_performance__priority_inheritance_count++; /* Increment the number of priority inheritance situations on this mutex. */ mutex_ptr -> tx_mutex_performance__priority_inheritance_count++; #endif } } /* Call actual thread suspension routine. */ _tx_thread_system_suspend(thread_ptr); #endif /* Return the completion status. */ status = thread_ptr -> tx_thread_suspend_status; } } else { /* Restore interrupts. */ TX_RESTORE /* Immediate return, return error completion. */ status = TX_NOT_AVAILABLE; } } /* Return completion status. */ return(status); }