New elegant I/O blocking solution

This is done using an internal scheduler syscall (127).

Very nice!

5 files changed, 50 insertions, 47 deletions

diff --git a/kernel/features/fs.c b/kernel/features/fs.c
index c3d5402..34c70e8 100644
--- a/kernel/features/fs.c
+++ b/kernel/features/fs.c
@@ -198,28 +198,6 @@ res vfs_write(const char *path, void *buf, u32 offset, u32 count)
 	return m->dev->vfs->write(path, buf, offset, count, m->dev);
 }
 
-res vfs_ioctl(const char *path, u32 request, void *arg1, void *arg2, void *arg3)
-{
-	if (!memory_readable(path))
-		return -EFAULT;
-
-	struct mount_info *m = vfs_find_mount_info(path);
-	if (!m || !m->dev || !m->dev->vfs)
-		return -ENOENT;
-
-	if (!m->dev->vfs->ioctl || !m->dev->vfs->perm)
-		return -EINVAL;
-
-	u32 len = strlen(m->path);
-	if (len > 1)
-		path += len;
-
-	if (m->dev->vfs->perm(path, VFS_WRITE, m->dev) != EOK && !proc_super())
-		return -EACCES;
-
-	return m->dev->vfs->ioctl(path, request, arg1, arg2, arg3, m->dev);
-}
-
 res vfs_stat(const char *path, struct stat *buf)
 {
 	if (!memory_readable(path))
diff --git a/kernel/features/io.c b/kernel/features/io.c
index 6042818..d0f1b1c 100644
--- a/kernel/features/io.c
+++ b/kernel/features/io.c
@@ -11,6 +11,7 @@
 #include <ps2.h>
 #include <rand.h>
 #include <str.h>
+#include <syscall.h>
 #include <timer.h>
 
 PROTECTED static struct io_dev *io_mappings[IO_MAX] = { 0 };
@@ -40,6 +41,7 @@ res io_poll(u32 *devs)
 	if (!memory_readable(devs))
 		return -EFAULT;
 
+	io_block(IO_BUS, proc_current()); // TODO!
 	for (u32 *p = devs; p && memory_readable(p) && *p; p++) {
 		if (!io_get(*p))
 			return -ENOENT;
@@ -84,30 +86,32 @@ res io_read(enum io_type io, void *buf, u32 offset, u32 count)
 	return dev->read(buf, offset, count);
 }
 
-void io_block(enum io_type io, struct proc *proc, struct regs *r)
+res io_ready(enum io_type io)
+{
+	struct io_dev *dev;
+	if (!(dev = io_get(io)))
+		return -ENOENT;
+
+	if (dev->ready && !dev->ready())
+		return -EAGAIN;
+
+	return EOK;
+}
+
+void io_block(enum io_type io, struct proc *proc)
 {
-	assert(r->eax == SYS_IOREAD);
 	assert(io_type_valid(io));
 	list_add(io_listeners[io], proc);
 	proc_state(proc_current(), PROC_BLOCKED);
-	proc_yield(r);
+	proc_yield();
 }
 
 void io_unblock(enum io_type io)
 {
-	struct page_dir *dir_bak;
-	memory_backup_dir(&dir_bak);
-
 	assert(io_type_valid(io));
 	struct node *iterator = io_listeners[io]->head;
 	while (iterator) {
 		struct proc *proc = iterator->data;
-		struct regs *r = &proc->regs;
-
-		memory_switch_dir(proc->page_dir);
-		r->eax = io_read(r->ebx, (void *)r->ecx, r->edx, r->esi);
-		memory_switch_dir(dir_bak);
-
 		proc_state(proc, PROC_RUNNING);
 		struct node *next = iterator->next;
 		list_remove(io_listeners[io], iterator);
diff --git a/kernel/features/mm.c b/kernel/features/mm.c
index d9e4577..9f0bd07 100644
--- a/kernel/features/mm.c
+++ b/kernel/features/mm.c
@@ -602,11 +602,17 @@ void memory_bypass_disable(void)
 
 u8 memory_is_user(const void *addr)
 {
+	if (!addr)
+		return 0;
+
 	return PDI((u32)addr) >= PAGE_KERNEL_COUNT;
 }
 
 u8 memory_readable(const void *addr)
 {
+	if (!addr)
+		return 0;
+
 	struct proc *proc = proc_current();
 	if (proc && !memory_bypass_validity)
 		return memory_is_user(addr) && virtual_user_readable(proc->page_dir, (u32)addr);
@@ -616,6 +622,9 @@ u8 memory_readable(const void *addr)
 
 u8 memory_writable(const void *addr)
 {
+	if (!addr)
+		return 0;
+
 	struct proc *proc = proc_current();
 	if (proc && !memory_bypass_validity)
 		return memory_is_user(addr) && virtual_user_writable(proc->page_dir, (u32)addr);
diff --git a/kernel/features/proc.c b/kernel/features/proc.c
index 6ddeb32..c972f1b 100644
--- a/kernel/features/proc.c
+++ b/kernel/features/proc.c
@@ -177,13 +177,13 @@ void proc_exit(struct proc *proc, struct regs *r, s32 status)
 
 	free(proc);
 
-	proc_yield(r);
+	proc_yield();
 }
 
-void proc_yield(struct regs *r)
+void proc_yield(void)
 {
 	proc_reset_quantum(PROC(current));
-	scheduler(r);
+	__asm__ volatile("int $127");
 }
 
 struct proc *proc_make(enum proc_priv priv)
diff --git a/kernel/features/syscall.c b/kernel/features/syscall.c
index 2c30a3b..94ea778 100644
--- a/kernel/features/syscall.c
+++ b/kernel/features/syscall.c
@@ -19,7 +19,6 @@
 static void syscall_handler(struct regs *r)
 {
 	enum sys num = r->eax;
-	r->eax = EOK;
 
 	/* printf("[SYSCALL] %d from %s\n", num, proc_current()->name); */
 
@@ -56,16 +55,18 @@ static void syscall_handler(struct regs *r)
 
 	// I/O operations
 	case SYS_IOPOLL: {
-		r->eax = io_poll((u32 *)r->ebx);
+		r->eax = io_poll((void *)r->ebx);
 		break;
 	}
 	case SYS_IOREAD: {
-		res ret = io_read(r->ebx, (void *)r->ecx, r->edx, r->esi);
-		if (ret == -EAGAIN) {
-			io_block(r->ebx, proc_current(), r);
-		} else {
-			r->eax = ret;
+		res ready = io_ready(r->ebx);
+		if (ready == -EAGAIN) {
+			io_block(r->ebx, proc_current());
+		} else if (ready != EOK) {
+			r->eax = ready;
+			break;
 		}
+		r->eax = io_read(r->ebx, (void *)r->ecx, r->edx, r->esi);
 		break;
 	}
 	case SYS_IOWRITE: {
@@ -87,7 +88,7 @@ static void syscall_handler(struct regs *r)
 		} else {
 			// TODO: Reimplement argc,argv
 			proc_stack_push(proc, 0);
-			proc_yield(r);
+			proc_yield();
 		}
 		break;
 	}
@@ -98,7 +99,7 @@ static void syscall_handler(struct regs *r)
 	}
 	case SYS_YIELD: {
 		r->eax = EOK;
-		proc_yield(r);
+		proc_yield();
 		break;
 	}
 
@@ -140,8 +141,19 @@ static void syscall_handler(struct regs *r)
 	}
 }
 
+// For kernel syscalls (internal)
+static void syscall_special_handler(struct regs *r)
+{
+	if (RING(r) != 0)
+		return;
+
+	scheduler(r);
+}
+
 CLEAR void syscall_init(void)
 {
-	idt_set_gate(0x80, (u32)isr128, 0x08, 0x8E);
+	idt_set_gate(0x7f, (u32)isr127, 0x08, 0x8e);
+	idt_set_gate(0x80, (u32)isr128, 0x08, 0xee);
+	isr_install_handler(0x7f, syscall_special_handler);
 	isr_install_handler(0x80, syscall_handler);
 }