add condvar

include/libtransistor/condvar.h

@@ -0,0 +1,48 @@
+/**
+ * @file libtransistor/condvar.h
+ * @brief Condition variables
+ */
+
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include<libtransistor/types.h>
+#include<libtransistor/mutex.h>
+
+typedef struct {
+	uint32_t key;
+} trn_condvar_t;
+
+#define TRN_CONDVAR_STATIC_INITIALIZER {.key = 0}
+
+/**
+ * @brief Creates a condition variable
+ *
+ * Alternatively, a statically allocated condition variable
+ * may be initialized with /ref TRN_CONDVAR_STATIC_INITIALIZER
+ */
+void trn_condvar_create(trn_condvar_t *condvar);
+
+/**
+ * @brief Signals n threads waiting on the condition variable, or -1 for all of them
+ */
+result_t trn_condvar_signal(trn_condvar_t *condvar, int n);
+
+/**
+ * @brief Waits for the condition variable to be signalled
+ * 
+ * @param timeout How long (in nanoseconds) to wait, or -1 for no timeout
+ */
+result_t trn_condvar_wait(trn_condvar_t *condvar, trn_mutex_t *mutex, uint64_t timeout) REQUIRES(mutex);
+
+/**
+ * @brief Destroys a condition variable
+ */
+void trn_condvar_destroy(trn_condvar_t *condvar);
+
+#ifdef __cplusplus
+}
+#endif

include/libtransistor/nx.h

@@ -24,6 +24,7 @@ extern "C" {
 #include<libtransistor/tls.h>
 #include<libtransistor/util.h>
 #include<libtransistor/mutex.h>
+#include<libtransistor/condvar.h>
 #include<libtransistor/thread.h>
 
 // filesystem

lib/condvar.c

@@ -0,0 +1,28 @@
+#include<libtransistor/condvar.h>
+
+#include<libtransistor/svc.h>
+#include<libtransistor/tls.h>
+
+void trn_condvar_create(trn_condvar_t *condvar) {
+	condvar->key = 0;
+}
+
+result_t trn_condvar_signal(trn_condvar_t *condvar, int n) {
+	return svcSignalProcessWideKey(&condvar->key, n);
+}
+
+result_t trn_condvar_wait(trn_condvar_t *condvar, trn_mutex_t *mutex, uint64_t timeout) NO_THREAD_SAFETY_ANALYSIS {
+	result_t r;
+
+	r = svcWaitProcessWideKeyAtomic((void*) &mutex->lock, &condvar->key, get_thread_handle(), timeout);
+
+	if(r == 0xea01) {
+		trn_mutex_lock(mutex);
+	}
+
+	return r;
+}
+
+void trn_condvar_destroy(trn_condvar_t *condvar) {
+	condvar->key = -1;
+}

mk/tests.mk

@@ -1,6 +1,6 @@
 # LIBTRANSISTOR TESTS
 
-libtransistor_TESTS := malloc bsd_ai_packing bsd sfdnsres nv helloworld hid hexdump args ssp stdin vi gpu display am sqfs_img audio_output init_fini_arrays ipc_server pthread ipc_fs fs_stress cpp unwind cpp_exceptions cpp_dynamic_memory hid_init_stress usb usb_serial thread mutex override_heap # fs_release_inodes
+libtransistor_TESTS := malloc bsd_ai_packing bsd sfdnsres nv helloworld hid hexdump args ssp stdin vi gpu display am sqfs_img audio_output init_fini_arrays ipc_server pthread ipc_fs fs_stress cpp unwind cpp_exceptions cpp_dynamic_memory hid_init_stress usb usb_serial thread mutex override_heap condvar # fs_release_inodes
 libtransistor_DYNAMIC_TESTS := simple dlfcn bad_resolution preemption elf
 
 # RUN RULES

mk/transistor_headers.mk

@@ -5,6 +5,7 @@ libtransistor_HEADER_NAMES := \
 	alloc_pages.h \
 	audio.h \
 	collections/list.h \
+	condvar.h \
 	display/binder.h \
 	display/display.h \
 	display/fence.h \

mk/transistor_objects.mk

@@ -4,6 +4,7 @@
 libtransistor_OBJECT_NAMES := \
 	address_space.o \
 	alloc_pages.o \
+	condvar.o \
 	crt0_common.o \
 	display/binder.o \
 	display/display.o \

test/test_condvar.c

@@ -0,0 +1,51 @@
+#include<libtransistor/util.h>
+#include<libtransistor/mutex.h>
+#include<libtransistor/condvar.h>
+#include<libtransistor/thread.h>
+#include<libtransistor/svc.h>
+
+#include<stdio.h>
+
+static trn_mutex_t mutex;
+static trn_condvar_t condvar;
+static volatile bool pred = 0;
+
+void other_thread(void *arg) {
+	printf("O: other thread started\n");
+
+	printf("O: trying to lock mutex\n");
+	trn_mutex_lock(&mutex);
+	printf("O: acquired mutex\n");
+	while(!pred) {
+		printf("O: waiting on condvar...\n");
+		trn_condvar_wait(&condvar, &mutex, -1);
+		printf("O: woke up\n");
+	}
+	trn_mutex_unlock(&mutex);
+}
+
+int main(int argc, char *argv[]) {
+	result_t r;
+	trn_mutex_create(&mutex);
+	trn_condvar_create(&condvar);
+
+	trn_thread_t thread;
+	ASSERT_OK(fail, trn_thread_create(&thread, other_thread, NULL, -1, -2, 1024 * 64, NULL));
+	ASSERT_OK(fail_thread, trn_thread_start(&thread));
+
+	printf("M: started other thread\n");
+	svcSleepThread(5000000000);
+	printf("M: signalling spuriously\n");
+	trn_condvar_signal(&condvar, 1);
+	svcSleepThread(5000000000);
+	printf("M: signalling\n");
+	pred = 1;
+	trn_condvar_signal(&condvar, 1);
+
+	trn_thread_join(&thread, -1);
+
+fail_thread:
+	trn_thread_destroy(&thread);
+fail:
+	return r;
+}