From c1bd3aa131d89abc128e2e9ddc24fd80c86c203e Mon Sep 17 00:00:00 2001 From: Christian Cunningham Date: Sat, 19 Mar 2022 10:30:45 -0700 Subject: Fixed Deadlock Mechanism --- src/util/mutex.c | 30 ++++++++++++++++++++++-------- 1 file changed, 22 insertions(+), 8 deletions(-) (limited to 'src') diff --git a/src/util/mutex.c b/src/util/mutex.c index 0525a3e..0a47a35 100644 --- a/src/util/mutex.c +++ b/src/util/mutex.c @@ -53,32 +53,46 @@ unsigned char delete_mutex(struct Mutex* m) return 0; } +void uart_mutexes(void) +{ + struct Entry* entry = mutex_manager.used.start.next; + while (entry->entry_type == VALUE_ENTRY) + { + struct Mutex* m = entry->value; + uart_hex(m); + uart_char(' '); + uart_hex(m->pid); + uart_char(' '); + uart_hexn(m->addr); + entry = entry->next; + } +} + void lock_mutex(struct Mutex* m) { struct Thread* rthread = scheduler.rthread; unsigned long rpid = rthread->pid; unsigned long mode = getmode() & 0x1F; if (mode == 0x10) { - sys1(SYS_LOCK, m); // Find this mutex struct Entry* mentry = find_value(m, &mutex_manager.used); // If it is not a managed mutex, break away if (mentry == 0) return; - // Get the next entry - mentry = mentry->next->next; + struct Entry* entry = mutex_manager.used.start.next; // Ensure this thread locks all mutexs sequentially // To avoid a deadlock - while (mentry->entry_type == VALUE_ENTRY) { - struct Mutex* vmutex = mentry->value; + while (entry->entry_type == VALUE_ENTRY) { + struct Mutex* vmutex = entry->value; // If this thread had locked it // Toggle the lock to prevent deadlock if (vmutex->pid == rpid) { - sys1(SYS_UNLOCK, m); - sys1(SYS_LOCK, m); + sys1(SYS_UNLOCK, vmutex); + sys1(SYS_LOCK, vmutex); } - mentry = mentry->next; + entry = entry->next; } + sys1(SYS_LOCK, m); } } -- cgit v1.2.1