fix: spinlock alignement issue in aarch64 causing so3 to crash

so3/arch/arm64/include/asm/spinlock.h

@@ -37,13 +37,15 @@ static inline int spin_trylock(spinlock_t *lock)
 {
 	uint32_t tmp;
 
-	__asm__ __volatile__("	ldaxr	%w0, [%1]\n"
-			     "	tbnz	%w0, #0, 1f\n"
+	/* The spinlock must aligned in aarch64 */
+	BUG_ON((((uint64_t)&lock->lock) & 0x7) != 0);
+	__asm__ __volatile__("	ldaxr	%x0, [%1]\n"
+			     "	cbnz	%x0, 1f\n"
 			     "	stxr	%w0, %2, [%1]\n"
 			     "1:"
 			     : "=&r"(tmp)
-			     : "r"(&lock->lock), "r"(1)
-			     : "cc");
+			     : "r"(&lock->lock), "r"(1ULL)
+			     : "cc", "memory");
 
 	if (tmp == 0) {
 		smp_mb();
@@ -66,10 +68,10 @@ static inline void spin_unlock(spinlock_t *lock)
 {
 	smp_mb();
 
-	__asm__ __volatile__("	stlr	wzr, [%0]\n"
+	__asm__ __volatile__("	stlr	xzr, [%0]\n"
 			     "	sev"
 			     :
 			     : "r"(&lock->lock)
-			     : "cc");
+			     : "cc", "memory");
 }
 #endif /* ASM_SPINLOCK_H */

so3/include/mutex.h

@@ -30,10 +30,10 @@
 #include <asm/atomic.h>
 
 struct mutex {
-	/* 1: unlocked, 0: locked, negative: locked, possible waiters */
-	atomic_t count;
 	tcb_t *owner;
 	spinlock_t wait_lock;
+	/* 1: unlocked, 0: locked, negative: locked, possible waiters */
+	atomic_t count;
 
 	/* Allow to manage recursive locking */
 	uint32_t recursive_count;
@@ -58,7 +58,7 @@ void mutex_unlock(struct mutex *lock);
 void mutex_init(struct mutex *lock);
 
 int do_mutex_init(void);
-int do_mutex_lock(mutex_t *lock);
-int do_mutex_unlock(mutex_t *lock);
+int do_mutex_lock(unsigned long number);
+int do_mutex_unlock(unsigned long number);
 
 #endif /* MUTEX_H */

so3/include/process.h

@@ -38,7 +38,7 @@
 #define PROC_STACK_SIZE (PROC_THREAD_MAX * THREAD_STACK_SIZE)
 
 #define FD_MAX 64
-#define N_MUTEX 10
+#define N_MUTEX 5
 
 typedef enum {
 	PROC_STATE_NEW,
@@ -126,7 +126,7 @@ struct pcb {
 	enum __ptrace_request ptrace_pending_req;
 
 	/* Mutex lock to be used in conjunction with the user space (very temporary) */
-	mutex_t lock[N_MUTEX];
+	mutex_t *lock;
 };
 typedef struct pcb pcb_t;
 

so3/include/spinlock.h

@@ -21,13 +21,24 @@
 
 #include <asm/processor.h>
 
+#ifdef CONFIG_ARCH_ARM32
+typedef struct {
+	volatile uint32_t lock;
+} spinlock_t;
+
+#elif CONFIG_ARCH_ARM64
+
 /*
  * On Aarch64, the field has to be 64-bit aligned apparently.
  */
 typedef struct {
-	__attribute__((aligned(8))) volatile uint32_t lock;
+	volatile uint64_t lock;
 } spinlock_t;
 
+#else
+#error "Invalid ARCH config"
+#endif
+
 #include <asm/spinlock.h>
 
 #define DEFINE_SPINLOCK(l) spinlock_t l = { 0 };

so3/kernel/mutex.c

@@ -22,6 +22,7 @@
  *
  */
 
+#include <errno.h>
 #include <mutex.h>
 #include <schedule.h>
 #include <string.h>
@@ -149,17 +150,23 @@ void mutex_unlock(struct mutex *lock)
 /*
  * The following syscall implementation are a first attempt, mainly used for debugging kernel mutexes.
  */
-int do_mutex_lock(mutex_t *lock)
+int do_mutex_lock(unsigned long number)
 {
-	mutex_lock(lock);
-
+	if (number >= N_MUTEX) {
+		set_errno(EINVAL);
+		return -1;
+	}
+	mutex_lock(&current()->pcb->lock[number]);
 	return 0;
 }
 
-int do_mutex_unlock(mutex_t *lock)
+int do_mutex_unlock(unsigned long number)
 {
-	mutex_unlock(lock);
-
+	if (number >= N_MUTEX) {
+		set_errno(EINVAL);
+		return -1;
+	}
+	mutex_unlock(&current()->pcb->lock[number]);
 	return 0;
 }
 

so3/kernel/process.c

@@ -193,10 +193,19 @@ pcb_t *new_process(void)
 	/* Reset the ptrace request indicator */
 	pcb->ptrace_pending_req = PTRACE_NO_REQUEST;
 
+	/* The spinlock inside the mutex must aligned in aarch64 */
+	pcb->lock = memalign(N_MUTEX * sizeof(mutex_t), 8);
+
+	if (!pcb->lock) {
+		printk("%s: failed to allocate memory for process mutex\n",
+		       __func__);
+		kernel_panic();
+	}
+
 	/* Initialize the mutex belonging to this process */
-	for (i = 0; i < N_MUTEX; i++)
+	for (i = 0; i < N_MUTEX; i++) {
 		mutex_init(&pcb->lock[i]);
-
+	}
 	/* Init the list of pages */
 	INIT_LIST_HEAD(&pcb->page_list);