kernel: idle process

7 files changed, 75 insertions, 30 deletions

diff --git a/src/init/main.c b/src/init/main.c
index f1e1e22..06e48cf 100644
--- a/src/init/main.c
+++ b/src/init/main.c
@@ -29,7 +29,7 @@ int main(void) {
 
 	MOUNT("/bind", fs_passthru(NULL));
 
-	if (!_syscall_fork()) {
+	if (false && !_syscall_fork()) {
 		__stdin = __stdout = _syscall_open(argify("/com1"));
 		if (__stdout < 0) _syscall_exit(1);
 
@@ -37,21 +37,21 @@ int main(void) {
 		_syscall_exit(1);
 	}
 
-	/*
-	 * if (!_syscall_fork()) {
-	 * 	__stdout = _syscall_open(argify("/vga_tty"));
-	 * 	if (__stdout < 0) _syscall_exit(1);
-
-	 * 	__stdin = _syscall_open(argify("/keyboard"));
-	 * 	if (__stdin < 0) {
-	 * 		printf("couldn't open /keyboard\n");
-	 * 		_syscall_exit(1);
-	 * 	}
-
-	 * 	shell_loop();
-	 * 	_syscall_exit(1);
-	 * }
-	 */
+
+	if (!_syscall_fork()) {
+		__stdout = _syscall_open(argify("/vga_tty"));
+		if (__stdout < 0) _syscall_exit(1);
+
+		__stdin = _syscall_open(argify("/keyboard"));
+		if (__stdin < 0) {
+			printf("couldn't open /keyboard\n");
+			_syscall_exit(1);
+		}
+
+		shell_loop();
+		_syscall_exit(1);
+	}
+
 
 	// try to find any working output
 	__stdout = _syscall_open(argify("/com1"));
diff --git a/src/kernel/arch/i386/driver/ps2.c b/src/kernel/arch/i386/driver/ps2.c
index 697bd34..5121b9e 100644
--- a/src/kernel/arch/i386/driver/ps2.c
+++ b/src/kernel/arch/i386/driver/ps2.c
@@ -7,17 +7,16 @@
 static volatile uint8_t backlog[BACKLOG_CAPACITY] = {};
 static volatile size_t backlog_size = 0;
 
+bool ps2_ready(void) {
+	return backlog_size > 0;
+}
+
 void ps2_recv(uint8_t s) {
 	if (backlog_size >= BACKLOG_CAPACITY) return;
 	backlog[backlog_size++] = s;
 }
 
 size_t ps2_read(uint8_t *buf, size_t len) {
-	irq_interrupt_flag(true);
-	while (backlog_size == 0)
-		asm("hlt" ::: "memory");
-	irq_interrupt_flag(false);
-
 	if (backlog_size <= len)
 		len = backlog_size;
 	backlog_size -= len; /* guaranteed to never be < 0 */
diff --git a/src/kernel/arch/i386/driver/ps2.h b/src/kernel/arch/i386/driver/ps2.h
index 4b56056..712b157 100644
--- a/src/kernel/arch/i386/driver/ps2.h
+++ b/src/kernel/arch/i386/driver/ps2.h
@@ -3,5 +3,6 @@
 #include <stddef.h>
 #include <stdint.h>
 
+bool	ps2_ready(void);
 void	ps2_recv(uint8_t scancode);
 size_t	ps2_read(uint8_t *buf, size_t max_len);
diff --git a/src/kernel/proc.c b/src/kernel/proc.c
index 2af352b..8e94d24 100644
--- a/src/kernel/proc.c
+++ b/src/kernel/proc.c
@@ -6,6 +6,8 @@
 #include <kernel/vfs/mount.h>
 #include <shared/mem.h>
 #include <stdint.h>
+#include <kernel/arch/i386/interrupts/irq.h> // TODO move irq stuff to arch/generic
+#include <kernel/vfs/root.h> // TODO
 
 struct process *process_first;
 struct process *process_current;
@@ -66,11 +68,30 @@ void process_switch(struct process *proc) {
 
 _Noreturn void process_switch_any(void) {
 	struct process *found = process_find(PS_RUNNING);
-	if (found)
-		process_switch(found);
+	if (found) process_switch(found);
+	process_idle();
+}
+
+_Noreturn void process_idle(void) {
+	struct process *procs[16];
+	size_t len = process_find_multiple(PS_WAITS4IRQ, procs, 16);
 
-	mem_debugprint();
-	cpu_shutdown();
+	if (len == 0) {
+		mem_debugprint();
+		cpu_shutdown();
+	}
+
+	irq_interrupt_flag(true);
+	for (;;) {
+		asm("hlt" ::: "memory"); // TODO move to irq.c
+		for (size_t i = 0; i < len; i++) {
+			if (procs[i]->waits4irq.ready()) {
+				irq_interrupt_flag(false);
+				vfs_root_handler(&procs[i]->waits4irq.req); // TODO this should be a function pointer too
+				process_switch_any();
+			}
+		}
+	}
 }
 
 // TODO there's no check for going past the stack - VULN
diff --git a/src/kernel/proc.h b/src/kernel/proc.h
index 2066b40..dc7525d 100644
--- a/src/kernel/proc.h
+++ b/src/kernel/proc.h
@@ -11,6 +11,7 @@ enum process_state {
 	PS_WAITS4CHILDDEATH,
 	PS_WAITS4FS,
 	PS_WAITS4REQUEST,
+	PS_WAITS4IRQ, // set by root vfs
 };
 
 struct process {
@@ -36,6 +37,10 @@ struct process {
 			int  max_len;
 			struct fs_wait_response __user *res;
 		} awaited_req; // PS_WAITS4REQUEST
+		struct {
+			struct vfs_request req;
+			bool (*ready)();
+		} waits4irq;
 	};
 	struct vfs_request *handled_req;
 
@@ -56,6 +61,9 @@ struct process *process_fork(struct process *parent);
 _Noreturn void process_switch(struct process *proc);
 _Noreturn void process_switch_any(void); // switches to any running process
 
+/** If there are any processes waiting for IRQs, wait with them. Otherwise, shut down */
+_Noreturn void process_idle(void);
+
 struct process *process_find(enum process_state);
 size_t process_find_multiple(enum process_state, struct process **buf, size_t max);
 
diff --git a/src/kernel/vfs/request.c b/src/kernel/vfs/request.c
index 5b65e52..e8bf147 100644
--- a/src/kernel/vfs/request.c
+++ b/src/kernel/vfs/request.c
@@ -7,7 +7,6 @@
 
 int vfs_request_create(struct vfs_request req_) {
 	struct vfs_request *req;
-	int ret;
 	process_current->state = PS_WAITS4FS;
 	process_current->waits4fs.queue_next = NULL;
 
@@ -20,9 +19,7 @@ int vfs_request_create(struct vfs_request req_) {
 
 	switch (req->backend->type) {
 		case VFS_BACK_ROOT:
-			ret = vfs_root_handler(req);
-			ret = vfs_request_finish(req, ret);
-			return ret;
+			return vfs_root_handler(req);
 		case VFS_BACK_USER:
 			if (req->backend->handler
 					&& req->backend->handler->state == PS_WAITS4REQUEST)
diff --git a/src/kernel/vfs/root.c b/src/kernel/vfs/root.c
index f61096c..89c2b3e 100644
--- a/src/kernel/vfs/root.c
+++ b/src/kernel/vfs/root.c
@@ -55,7 +55,7 @@ static void req_preprocess(struct vfs_request *req, int max_len) {
 	assert(req->input.len + req->offset <= max_len);
 }
 
-int vfs_root_handler(struct vfs_request *req) {
+static int handle(struct vfs_request *req, bool *ready) {
 	switch (req->type) {
 		case VFSOP_OPEN:
 			if (exacteq(req, "/"))		return HANDLE_ROOT;
@@ -105,6 +105,16 @@ int vfs_root_handler(struct vfs_request *req) {
 					return iter.prior;
 				}
 				case HANDLE_PS2: {
+					if (!ps2_ready()) {
+						*ready = false;
+						req->caller->state = PS_WAITS4IRQ;
+						/* not copying any memory, both sides point to the same
+						 * struct. this line's only there so i don't depend on
+						 * struct alignment always staying the same */
+						req->caller->waits4irq.req = *req;
+						req->caller->waits4irq.ready = ps2_ready;
+						return -1;
+					}
 					uint8_t buf[16];
 					size_t len = ps2_read(buf, sizeof buf);
 					virt_cpy_to(req->caller->pages, req->output.buf, buf, len);
@@ -163,3 +173,12 @@ int vfs_root_handler(struct vfs_request *req) {
 		default: panic_invalid_state();
 	}
 }
+
+int vfs_root_handler(struct vfs_request *req) {
+	bool ready = true;
+	int ret = handle(req, &ready);
+	if (ready)
+		return vfs_request_finish(req, ret);
+	else
+		return -1;
+}