lkl: Change tls key to a struct lkl_tls_key

So the key can be a compound structure allowing flexible custom tls
implementation

Signed-off-by: Yuan Liu <liuyuan@google.com>

arch/lkl/include/uapi/asm/host_ops.h

@@ -4,6 +4,7 @@
 /* Defined in {posix,nt}-host.c */
 struct lkl_mutex;
 struct lkl_sem;
+struct lkl_tls_key;
 typedef unsigned long lkl_thread_t;
 struct lkl_jmp_buf {
 	unsigned long buf[32];
@@ -93,10 +94,10 @@ struct lkl_host_operations {
 	lkl_thread_t (*thread_self)(void);
 	int (*thread_equal)(lkl_thread_t a, lkl_thread_t b);
 
-	int (*tls_alloc)(unsigned int *key, void (*destructor)(void *));
-	int (*tls_free)(unsigned int key);
-	int (*tls_set)(unsigned int key, void *data);
-	void *(*tls_get)(unsigned int key);
+	struct lkl_tls_key *(*tls_alloc)(void (*destructor)(void *));
+	void (*tls_free)(struct lkl_tls_key *key);
+	int (*tls_set)(struct lkl_tls_key *key, void *data);
+	void *(*tls_get)(struct lkl_tls_key *key);
 
 	void* (*mem_alloc)(unsigned long);
 	void (*mem_free)(void *);

arch/lkl/kernel/syscalls.c

@@ -88,7 +88,7 @@ static void del_host_task(void *arg)
 	do_exit(0);
 }
 
-static unsigned int task_key;
+static struct lkl_tls_key *task_key;
 
 long lkl_syscall(long no, long *params)
 {
@@ -121,19 +121,17 @@ long lkl_syscall(long no, long *params)
 
 int syscalls_init(void)
 {
-	int ret = 0;
-
 	snprintf(current->comm, sizeof(current->comm), "host0");
 	set_thread_flag(TIF_HOST_THREAD);
 	host0 = current;
 
 	if (lkl_ops->tls_alloc) {
-		ret = lkl_ops->tls_alloc(&task_key, del_host_task);
-		if (ret)
-			return ret;
+		task_key = lkl_ops->tls_alloc(del_host_task);
+		if (!task_key)
+			return -1;
 	}
 
-	return ret;
+	return 0;
 }
 
 void syscalls_cleanup(void)

tools/lkl/lib/nt-host.c

@@ -17,6 +17,10 @@ struct lkl_sem {
 	HANDLE sem;
 };
 
+struct lkl_tls_key {
+	DWORD key;
+};
+
 static struct lkl_sem *sem_alloc(int count)
 {
 	struct lkl_sem *sem = malloc(sizeof(struct lkl_sem));
@@ -122,28 +126,34 @@ static int thread_equal(lkl_thread_t a, lkl_thread_t b)
 	return a == b;
 }
 
-static int tls_alloc(unsigned int *key, void (*destructor)(void *))
+static struct lkl_tls_key *tls_alloc(void (*destructor)(void *))
 {
-	*key = FlsAlloc((PFLS_CALLBACK_FUNCTION)destructor);
-	return *key == TLS_OUT_OF_INDEXES ? -1 : 0;
+	struct lkl_tls_key *ret = malloc(sizeof(struct lkl_tls_key));
+
+	ret->key = FlsAlloc((PFLS_CALLBACK_FUNCTION)destructor);
+	if (ret->key == TLS_OUT_OF_INDEXES) {
+		free(ret);
+		return -1;
+	}
+	return 0;
 }
 
-static int tls_free(unsigned int key)
+static void tls_free(struct lkl_tls_key *key)
 {
 	/* setting to NULL first to prevent the callback from being called */
-	if (!FlsSetValue(key, NULL))
-		return -1;
-	return FlsFree(key) ? 0 : -1;
+	FlsSetValue(key->key, NULL);
+	FlsFree(key->key);
+	free(key);
 }
 
-static int tls_set(unsigned int key, void *data)
+static int tls_set(struct lkl_tls_key *key, void *data)
 {
-	return FlsSetValue(key, data) ? 0 : -1;
+	return FlsSetValue(key->key, data) ? 0 : -1;
 }
 
-static void *tls_get(unsigned int key)
+static void *tls_get(struct lkl_tls_key *key)
 {
-	return FlsGetValue(key);
+	return FlsGetValue(key->key);
 }
 
 

tools/lkl/lib/posix-host.c

@@ -49,6 +49,10 @@ struct lkl_sem {
 #endif /* _POSIX_SEMAPHORES */
 };
 
+struct lkl_tls_key {
+	pthread_key_t key;
+};
+
 #define WARN_UNLESS(exp) do {						\
 		if (exp < 0)						\
 			lkl_printf("%s: %s\n", #exp, strerror(errno));	\
@@ -216,24 +220,33 @@ static int thread_equal(lkl_thread_t a, lkl_thread_t b)
 	return pthread_equal(a, b);
 }
 
-static int tls_alloc(unsigned int *key, void (*destructor)(void *))
+static struct lkl_tls_key *tls_alloc(void (*destructor)(void *))
 {
-	return pthread_key_create((pthread_key_t *)key, destructor);
+	struct lkl_tls_key *ret = malloc(sizeof(struct lkl_tls_key));
+
+	if (WARN_PTHREAD(pthread_key_create(&ret->key, destructor))) {
+		free(ret);
+		return NULL;
+	}
+	return ret;
 }
 
-static int tls_free(unsigned int key)
+static void tls_free(struct lkl_tls_key *key)
 {
-	return pthread_key_delete(key);
+	WARN_PTHREAD(pthread_key_delete(key->key));
+	free(key);
 }
 
-static int tls_set(unsigned int key, void *data)
+static int tls_set(struct lkl_tls_key *key, void *data)
 {
-	return pthread_setspecific(key, data);
+	if (WARN_PTHREAD(pthread_setspecific(key->key, data)))
+		return -1;
+	return 0;
 }
 
-static void *tls_get(unsigned int key)
+static void *tls_get(struct lkl_tls_key *key)
 {
-	return pthread_getspecific(key);
+	return pthread_getspecific(key->key);
 }
 
 static unsigned long long time_ns(void)