Add kernel worker threads for handling various tasks (eg. interrupts)

13 files changed, 171 insertions, 13 deletions

diff --git a/src/common/include/fs.h b/src/common/include/fs.h
index b3a618b..70f0169 100644
--- a/src/common/include/fs.h
+++ b/src/common/include/fs.h
@@ -20,10 +20,11 @@
 #define FM_CREATE   (0x10)
 #define FM_TRUNC    (0x20)
 #define FM_APPEND   (0x40)
-#define FM_IOCTL	(0x80)
-#define FM_DCREATE	(0x100)		// create file in directory
-#define FM_DMOVE	(0x200)		// move file from directory
-#define FM_DUNLINK	(0x400)		// delete file from directory
+#define FM_IOCTL	(0x100)
+#define FM_BLOCKING	(0x200)
+#define FM_DCREATE	(0x1000)		// create file in directory
+#define FM_DMOVE	(0x2000)		// move file from directory
+#define FM_DUNLINK	(0x4000)		// delete file from directory
 
 typedef struct {
 	int type;
diff --git a/src/common/include/syscallproto.h b/src/common/include/syscallproto.h
index ede8cb1..fd56017 100644
--- a/src/common/include/syscallproto.h
+++ b/src/common/include/syscallproto.h
@@ -6,6 +6,7 @@
 #define SC_DBG_PRINT	0		// args: msg, msg_strlen
 #define SC_EXIT			1		// args: code
 #define SC_YIELD		2		// args: ()
+#define SC_USLEEP		3		// args: usecs
 
 #define	SC_MMAP			10		// args: addr, size, mode
 #define SC_MMAP_FILE	11		// args: handle, offset, addr, size, mode
diff --git a/src/kernel/Makefile b/src/kernel/Makefile
index a6f9a1b..20bbfe0 100644
--- a/src/kernel/Makefile
+++ b/src/kernel/Makefile
@@ -1,7 +1,7 @@
 
 OBJ = core/loader.o core/dbglog.o \
 	core/gdt.o core/idt.o core/interrupt.o core/context_switch.o core/thread.o \
-	core/frame.o core/paging.o core/region.o core/kmalloc.o \
+	core/frame.o core/paging.o core/region.o core/kmalloc.o core/worker.o \
 	user/vfs.o user/nullfs.o user/process.o user/elf.o user/syscall.o
 
 LIB = ../common/libc/libc.lib ../common/libkogata/libkogata.lib ../common/libalgo/libalgo.lib
diff --git a/src/kernel/core/kmain.c b/src/kernel/core/kmain.c
index c8ca920..12c813e 100644
--- a/src/kernel/core/kmain.c
+++ b/src/kernel/core/kmain.c
@@ -11,6 +11,7 @@
 #include <region.h>
 #include <kmalloc.h>
 
+#include <worker.h>
 #include <thread.h>
 
 #include <vfs.h>
@@ -120,21 +121,29 @@ void kernel_init_stage2(void* data) {
 	dbg_print_region_info();
 	dbg_print_frame_stats();
 
+	// Launch some worker threads
+	start_workers(2);
+
+	// test sleep()
+	dbg_printf("Testing sleep() : ");
+	for (int i = 0; i < 20; i++) {
+		usleep(50000);
+		dbg_printf(".");
+	}
+	dbg_printf("\n");
+
 	TEST_PLACEHOLDER_AFTER_TASKING;
 
 	// Create devfs
 	register_nullfs_driver();
-	fs_t *devfs = make_fs("nullfs", 0, "cd");
+	fs_t *devfs = make_fs("nullfs", 0, "");
 	ASSERT(devfs != 0);
 
 	// Add kernel command line to devfs
 	{
 		dbg_printf("Kernel command line: '%s'\n", (char*)mbd->cmdline);
 		size_t len = strlen((char*)mbd->cmdline);
-		fs_handle_t* cmdline = fs_open(devfs, "/cmdline", FM_WRITE | FM_CREATE);
-		ASSERT(cmdline != 0);
-		ASSERT(file_write(cmdline, 0, len, (char*)mbd->cmdline) == len);
-		unref_file(cmdline);
+		ASSERT(nullfs_add_ram_file(devfs, "/cmdline", (char*)mbd->cmdline, len, false, FM_READ));
 	}
 
 	// Populate devfs with files for kernel modules
diff --git a/src/kernel/core/thread.c b/src/kernel/core/thread.c
index e62b5a8..7f9f25e 100644
--- a/src/kernel/core/thread.c
+++ b/src/kernel/core/thread.c
@@ -6,6 +6,7 @@
 
 #include <frame.h>
 #include <paging.h>
+#include <worker.h>
 
 void save_context_and_enter_scheduler(saved_context_t *ctx);
 void resume_context(saved_context_t *ctx);
@@ -155,6 +156,7 @@ thread_t *new_thread(entry_t entry, void* data) {
 // ========== //
 
 static void irq0_handler(registers_t *regs) {
+	worker_notify_time(1000000 / TASK_SWITCH_FREQUENCY);
 	if (current_thread != 0) {
 		save_context_and_enter_scheduler(&current_thread->ctx);
 	}
@@ -195,6 +197,16 @@ void pause() {
 	resume_interrupts(st);
 }
 
+void usleep(int usecs) {
+	void sleeper_resume(void* t) {
+		thread_t *thread = (thread_t*)t;
+		resume_thread(thread, true);
+	}
+	if (current_thread == 0) return;
+	bool ok = worker_push_in(usecs, sleeper_resume, current_thread);
+	if (ok) pause();
+}
+
 void exit() {
 	current_thread->state = T_STATE_FINISHED;
 	// TODO : add job for deleting the thread, or whatever
@@ -202,16 +214,21 @@ void exit() {
 	ASSERT(false);
 }
 
-void resume_thread(thread_t *thread, bool run_at_once) {
+bool resume_thread(thread_t *thread, bool run_at_once) {
+	bool ret = false;
+
 	bool st = disable_interrupts();
 
 	if (thread->state == T_STATE_PAUSED) {
+		ret = true;
 		thread->state = T_STATE_RUNNING;
 		enqueue_thread(thread, false);
 	}
 	if (run_at_once) yield();
 
 	resume_interrupts(st);
+
+	return ret;
 }
 
 /* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/kernel/core/worker.c b/src/kernel/core/worker.c
new file mode 100644
index 0000000..4be2f93
--- /dev/null
+++ b/src/kernel/core/worker.c
@@ -0,0 +1,100 @@
+#include <worker.h>
+#include <btree.h>
+#include <mutex.h>
+#include <malloc.h>
+
+static uint64_t time = 0;
+static uint64_t next_task_time = UINT64_MAX;
+
+static thread_t **workers = 0;
+static int nworkers = 0;
+
+static btree_t *tasks = 0;
+STATIC_MUTEX(tasks_mutex);
+
+static void worker_thread(void*);
+
+typedef struct {
+	uint64_t time;
+	entry_t fun;
+	void* data;
+} worker_task_t;
+
+int uint64_key_cmp_fun(const void* a, const void* b) {
+	uint64_t *x = (uint64_t*)a, *y = (uint64_t*)b;
+	return (*x == *y ? 0 : (*x > *y ? 1 : -1));
+}
+
+void start_workers(int n) {
+	ASSERT(n > 0);
+	workers = (thread_t**)malloc(n * sizeof(thread_t*));
+	ASSERT(workers != 0);
+
+	tasks = create_btree(uint64_key_cmp_fun, 0);
+	ASSERT(tasks != 0);
+
+	nworkers = n;
+	for (int i = 0; i < n; i++) {
+		workers[i] = new_thread(worker_thread, 0);
+	}
+}
+
+void worker_thread(void* x) {
+	uint64_t zero64 = 0;
+
+	while (true) {
+		mutex_lock(&tasks_mutex);
+		worker_task_t *t = btree_upper(tasks, &zero64);
+		next_task_time = (t == 0 ? UINT64_MAX : t->time);
+		if (t != 0 && t->time <= time) {
+			btree_remove_v(tasks, &t->time, t);
+		} else {
+			t = 0;
+		}
+		mutex_unlock(&tasks_mutex);
+		
+		if (t != 0) {
+			// do task :-)
+			t->fun(t->data);
+			free(t);
+		} else {
+			pause();
+		}
+	}
+}
+
+bool worker_push_in(int usecs, entry_t fun, void* data) {
+	worker_task_t *t = (worker_task_t*)malloc(sizeof(worker_task_t));
+	if (t == 0) return false;
+
+	t->time = time + usecs;
+	t->fun = fun;
+	t->data = data;
+
+	mutex_lock(&tasks_mutex);
+	btree_add(tasks, &t->time, t);
+	mutex_unlock(&tasks_mutex);
+	
+	if (t->time < next_task_time) next_task_time = t->time;
+
+	return true;
+}
+
+bool worker_push(entry_t fun, void* data) {
+	return worker_push_in(0, fun, data);
+}
+
+void worker_notify_time(int usecs) {
+	time += usecs;
+	if (next_task_time <= time) {
+		for (int i = 0; i < nworkers; i++) {
+			if (resume_thread(workers[i], false)) break;
+		}
+	}
+}
+
+uint64_t worker_get_time() {
+	return time;
+}
+
+/* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/kernel/include/thread.h b/src/kernel/include/thread.h
index c8072c9..8ffbb3d 100644
--- a/src/kernel/include/thread.h
+++ b/src/kernel/include/thread.h
@@ -11,7 +11,7 @@
 
 #define KPROC_STACK_SIZE 0x8000	// 8Kb
 
-#define TASK_SWITCH_FREQUENCY	50		// in herz
+#define TASK_SWITCH_FREQUENCY	100		// in herz
 
 typedef struct saved_context {
 	uint32_t *esp;
@@ -43,8 +43,9 @@ extern thread_t *current_thread;
 void yield();
 void pause();
 void exit();
+void usleep(int usecs);
 
-void resume_thread(thread_t *thread, bool run_at_once);
+bool resume_thread(thread_t *thread, bool run_at_once); // true if thrad was paused, false if was running
 void kill_thread(thread_t *thread);
 
 /* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/kernel/include/worker.h b/src/kernel/include/worker.h
new file mode 100644
index 0000000..ec76dc4
--- /dev/null
+++ b/src/kernel/include/worker.h
@@ -0,0 +1,15 @@
+#pragma once
+
+#include <thread.h>
+#include <mutex.h>
+
+void start_workers(int num_worker_threads);		// default : one is enough
+
+bool worker_push(entry_t fun, void* data);
+bool worker_push_in(int usecs, entry_t fun, void* data);
+
+void worker_notify_time(int usecs);		// time source : PIT IRQ0
+
+uint64_t worker_get_time();				// usecs since we started some worker threads, ie since kernel startup
+
+/* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/kernel/user/syscall.c b/src/kernel/user/syscall.c
index 6fdd633..f1f5f86 100644
--- a/src/kernel/user/syscall.c
+++ b/src/kernel/user/syscall.c
@@ -43,6 +43,11 @@ static uint32_t yield_sc(sc_args_t args) {
 	return 0;
 }
 
+static uint32_t usleep_sc(sc_args_t args) {
+	usleep(args.a);
+	return 0;
+}
+
 static uint32_t dbg_print_sc(sc_args_t args) {
 	char* msg = sc_copy_string(args.a, args.b);
 	if (msg == 0) return -1;
@@ -287,6 +292,7 @@ void setup_syscall_table() {
 	sc_handlers[SC_EXIT] = exit_sc;
 	sc_handlers[SC_YIELD] = yield_sc;
 	sc_handlers[SC_DBG_PRINT] = dbg_print_sc;
+	sc_handlers[SC_USLEEP] = usleep_sc;
 
 	sc_handlers[SC_MMAP] = mmap_sc;
 	sc_handlers[SC_MMAP_FILE] = mmap_file_sc;
diff --git a/src/lib/include/syscall.h b/src/lib/include/syscall.h
index 0f1efb0..fb82c33 100644
--- a/src/lib/include/syscall.h
+++ b/src/lib/include/syscall.h
@@ -15,6 +15,7 @@ typedef int fd_t;
 void dbg_print(const char* str);
 void yield();
 void exit(int code);
+void usleep(int usecs);
 
 bool mmap(void* addr, size_t size, int mode);
 bool mmap_file(fd_t file, size_t offset, void* addr, size_t size, int mode);
diff --git a/src/lib/libkogata/syscall.c b/src/lib/libkogata/syscall.c
index 2e0ef0f..afda7c7 100644
--- a/src/lib/libkogata/syscall.c
+++ b/src/lib/libkogata/syscall.c
@@ -35,6 +35,10 @@ void exit(int code) {
 	call(SC_EXIT, code, 0, 0, 0, 0);
 }
 
+void usleep(int usecs) {
+	call(SC_USLEEP, usecs, 0, 0, 0, 0);
+}
+
 bool mmap(void* addr, size_t size, int mode) {
 	return call(SC_MMAP, (uint32_t)addr, size, mode, 0, 0);
 }
diff --git a/src/tests/utests/fs1/test.c b/src/tests/utests/fs1/test.c
index e95449d..247373d 100644
--- a/src/tests/utests/fs1/test.c
+++ b/src/tests/utests/fs1/test.c
@@ -38,3 +38,4 @@ int main(int argc, char **argv) {
 	return 0;
 }
 
+/* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/tests/utests/malloc/test.c b/src/tests/utests/malloc/test.c
index bc11d9d..b55d28a 100644
--- a/src/tests/utests/malloc/test.c
+++ b/src/tests/utests/malloc/test.c
@@ -38,3 +38,5 @@ int main(int argc, char **argv) {
 
 	return 0;
 }
+
+/* vim: set ts=4 sw=4 tw=0 noet :*/