1 /**************************************************************************/ 2 /* */ 3 /* Copyright (c) Microsoft Corporation. All rights reserved. */ 4 /* */ 5 /* This software is licensed under the Microsoft Software License */ 6 /* Terms for Microsoft Azure RTOS. Full text of the license can be */ 7 /* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */ 8 /* and in the root directory of this software. */ 9 /* */ 10 /**************************************************************************/ 11 12 13 /**************************************************************************/ 14 /**************************************************************************/ 15 /** */ 16 /** ThreadX Component */ 17 /** */ 18 /** Thread */ 19 /** */ 20 /**************************************************************************/ 21 /**************************************************************************/ 22 23 24 #define TX_SOURCE_CODE 25 #define TX_THREAD_SMP_SOURCE_CODE 26 27 28 /* Include necessary system files. */ 29 30 #include "tx_api.h" 31 #include "tx_thread.h" 32 #include "tx_timer.h" 33 34 35 /**************************************************************************/ 36 /* */ 37 /* FUNCTION RELEASE */ 38 /* */ 39 /* _tx_thread_context_save SMP/Linux/GCC */ 40 /* 6.1 */ 41 /* AUTHOR */ 42 /* */ 43 /* William E. Lamie, Microsoft Corporation */ 44 /* */ 45 /* DESCRIPTION */ 46 /* */ 47 /* This function saves the context of an executing thread in the */ 48 /* beginning of interrupt processing. The function also ensures that */ 49 /* the system stack is used upon return to the calling ISR. */ 50 /* */ 51 /* INPUT */ 52 /* */ 53 /* None */ 54 /* */ 55 /* OUTPUT */ 56 /* */ 57 /* None */ 58 /* */ 59 /* CALLS */ 60 /* */ 61 /* _tx_linux_debug_entry_insert */ 62 /* _tx_linux_mutex_obtain */ 63 /* _tx_linux_thread_suspend */ 64 /* */ 65 /* CALLED BY */ 66 /* */ 67 /* ISRs */ 68 /* */ 69 /* RELEASE HISTORY */ 70 /* */ 71 /* DATE NAME DESCRIPTION */ 72 /* */ 73 /* 09-30-2020 William E. Lamie Initial Version 6.1 */ 74 /* */ 75 /**************************************************************************/ _tx_thread_context_save(VOID)76VOID _tx_thread_context_save(VOID) 77 { 78 79 TX_THREAD *thread_ptr; 80 UINT interrupt_posture; 81 82 /* Loop to perform retries on thread preemption. */ 83 while(1) 84 { 85 86 /* Lock mutex to ensure other threads are not playing with 87 the core ThreadX data structures. */ 88 interrupt_posture = _tx_thread_smp_protect(); 89 90 /* Check for a system error condition. */ 91 if (interrupt_posture != TX_FALSE) 92 { 93 94 /* This should not happen... increment the system error counter. */ 95 _tx_linux_system_error++; 96 } 97 98 /* Debug entry. */ 99 _tx_linux_debug_entry_insert("CONTEXT_SAVE", __FILE__, __LINE__); 100 101 /* All ISRs are assumed to be serviced on core 0. */ 102 103 /* Pickup the current thread pointer. */ 104 thread_ptr = _tx_thread_current_ptr[0]; 105 106 /* If an application thread is running, suspend it to simulate preemption. */ 107 if ((thread_ptr) && (_tx_thread_system_state[0] == 0)) 108 { 109 110 /* Yes, this is the first interrupt and an application thread is running... 111 suspend it! */ 112 _tx_linux_thread_suspend(thread_ptr -> tx_thread_linux_thread_id); 113 114 /* Debug entry. */ 115 _tx_linux_debug_entry_insert("CONTEXT_SAVE-suspend_thread", __FILE__, __LINE__); 116 } 117 118 /* Increment the nested interrupt condition. */ 119 _tx_thread_system_state[0]++; 120 121 /* Do not release the protection for ISRs, since in SMP mode other threads might be scheduled on 122 interrupted virtual core 0, which will confuse ThreadX. */ 123 124 /* Get out of the loop. */ 125 break; 126 } 127 } 128 129
