Some small fixes here and there

6 files changed, 45 insertions, 16 deletions

diff --git a/kernel/drivers/fb.c b/kernel/drivers/fb.c
index 2a29eb7..8831a52 100644
--- a/kernel/drivers/fb.c
+++ b/kernel/drivers/fb.c
@@ -24,12 +24,11 @@ struct vbe_basic {
 
 PROTECTED static struct vbe_basic *vbe = NULL;
 
-static void fb_map_buffer(struct page_dir *dir)
+static u32 fb_map_buffer(struct page_dir *dir)
 {
-	// TODO: Return virtual mapped address
 	assert(vbe);
 	u32 size = vbe->height * vbe->pitch;
-	memory_map_identity(dir, memory_range_around((u32)vbe->fb, size), MEMORY_USER);
+	return virtual_alloc(dir, memory_range_around((u32)vbe->fb, size), MEMORY_USER).base;
 }
 
 static u32 fb_owner = 0;
@@ -52,8 +51,9 @@ static res fb_ioctl(u32 request, void *arg1, void *arg2, void *arg3)
 		else
 			fb_owner = proc_current()->pid;
 
+		u32 fb = fb_map_buffer(proc_current()->page_dir);
+		vbe->fb = (u8 *)fb;
 		memcpy_user(arg1, vbe, size);
-		fb_map_buffer(proc_current()->page_dir);
 		return EOK;
 	}
 	default:
@@ -69,5 +69,8 @@ CLEAR void fb_install(void)
 	dev->control = fb_ioctl;
 	io_add(IO_FRAMEBUFFER, dev);
 
-	fb_map_buffer(virtual_kernel_dir());
+	// Identity map framebuffer to kernel to prevent unwanted writing
+	u32 size = vbe->height * vbe->pitch;
+	memory_map_identity(virtual_kernel_dir(), memory_range_around((u32)vbe->fb, size),
+			    MEMORY_CLEAR);
 }
diff --git a/kernel/drivers/gdt.c b/kernel/drivers/gdt.c
index 66a9086..8209eaf 100644
--- a/kernel/drivers/gdt.c
+++ b/kernel/drivers/gdt.c
@@ -5,6 +5,17 @@
 #include <gdt.h>
 #include <mem.h>
 
+#define GDT_MAX_LIMIT 0xffff
+#define GDT_PRESENT (1 << 7)
+#define GDT_RING3 (3 << 5)
+#define GDT_DESCRIPTOR (1 << 4)
+#define GDT_EXECUTABLE (1 << 3)
+#define GDT_READWRITE (1 << 1)
+#define GDT_ACCESSED (1 << 0)
+#define GDT_GRANULARITY (0x80 | 0x00)
+#define GDT_SIZE (0x40 | 0x00)
+#define GDT_DATA_OFFSET 0x10
+
 static struct gdt_entry gdt[6] = { 0 };
 static struct tss_entry tss = { 0 };
 
@@ -24,12 +35,14 @@ CLEAR static void gdt_set_gate(u32 num, u32 base, u32 limit, u8 access, u8 gran)
 	gdt[num].access = access;
 }
 
+// TODO: Fix GPF for in/out operations in userspace (not necessarily a TSS problem)
 CLEAR static void tss_write(u32 num, u16 ss0, u32 esp0)
 {
 	u32 base = (u32)&tss;
 	u32 limit = base + sizeof(tss);
 
-	gdt_set_gate(num, base, limit, 0xe9, 0x00);
+	gdt_set_gate(num, base, limit, GDT_PRESENT | GDT_RING3 | GDT_EXECUTABLE | GDT_ACCESSED,
+		     GDT_SIZE);
 
 	memset(&tss, 0, sizeof(tss));
 
@@ -41,7 +54,7 @@ CLEAR static void tss_write(u32 num, u16 ss0, u32 esp0)
 
 CLEAR static void tss_flush(void)
 {
-	__asm__ volatile("ltr %0" ::"r"((u16)0x2b));
+	__asm__ volatile("ltr %0" ::"r"((u16)((u32)&gdt[5] - (u32)gdt)));
 }
 
 CLEAR static void gdt_flush(void)
@@ -59,23 +72,29 @@ void tss_set_stack(u32 ss, u32 esp)
 CLEAR void gdt_install(u32 esp)
 {
 	// Set GDT pointer and limit
-	gp.limit = (sizeof(struct gdt_entry) * 6) - 1;
+	gp.limit = sizeof(gdt) - 1;
 	gp.base = &gdt;
 
 	// NULL descriptor
 	gdt_set_gate(0, 0, 0, 0, 0);
 
 	// Code segment
-	gdt_set_gate(1, 0, 0xffffffff, 0x9a, 0xcf);
+	gdt_set_gate(1, 0, 0xffffffff,
+		     GDT_PRESENT | GDT_DESCRIPTOR | GDT_EXECUTABLE | GDT_READWRITE,
+		     GDT_GRANULARITY | GDT_SIZE);
 
 	// Data segment
-	gdt_set_gate(2, 0, 0xffffffff, 0x92, 0xcf);
+	gdt_set_gate(2, 0, 0xffffffff, GDT_PRESENT | GDT_DESCRIPTOR | GDT_READWRITE,
+		     GDT_GRANULARITY | GDT_SIZE);
 
 	// User mode code segment
-	gdt_set_gate(3, 0, 0xffffffff, 0xfa, 0xcf);
+	gdt_set_gate(3, 0, 0xffffffff,
+		     GDT_PRESENT | GDT_RING3 | GDT_DESCRIPTOR | GDT_EXECUTABLE | GDT_READWRITE,
+		     GDT_GRANULARITY | GDT_SIZE);
 
 	// User mode data segment
-	gdt_set_gate(4, 0, 0xffffffff, 0xf2, 0xcf);
+	gdt_set_gate(4, 0, 0xffffffff, GDT_PRESENT | GDT_RING3 | GDT_DESCRIPTOR | GDT_READWRITE,
+		     GDT_GRANULARITY | GDT_SIZE);
 
 	// Write TSS
 	tss_write(5, GDT_SUPER_DATA_OFFSET, esp);
diff --git a/kernel/drivers/interrupts.c b/kernel/drivers/interrupts.c
index 5b94b94..7a57a91 100644
--- a/kernel/drivers/interrupts.c
+++ b/kernel/drivers/interrupts.c
@@ -188,7 +188,7 @@ void isr_panic(struct regs *r)
 	} else {
 		__asm__ volatile("cli\nhlt");
 	}
-	proc_yield();
+	proc_yield_regs(r);
 }
 
 void isr_handler(struct regs *r);
diff --git a/kernel/features/proc.c b/kernel/features/proc.c
index 36ee6b9..3039231 100644
--- a/kernel/features/proc.c
+++ b/kernel/features/proc.c
@@ -185,7 +185,7 @@ void proc_exit(struct proc *proc, struct regs *r, s32 status)
 
 	free(proc);
 
-	proc_yield();
+	proc_yield_regs(r);
 }
 
 void proc_yield(void)
@@ -195,6 +195,12 @@ void proc_yield(void)
 	__asm__ volatile("int $127");
 }
 
+void proc_yield_regs(struct regs *r)
+{
+	proc_reset_quantum(PROC(current));
+	scheduler(r);
+}
+
 struct proc *proc_make(enum proc_priv priv)
 {
 	struct proc *proc = zalloc(sizeof(*proc));
diff --git a/kernel/features/syscall.c b/kernel/features/syscall.c
index 23c8d37..b66cd2e 100644
--- a/kernel/features/syscall.c
+++ b/kernel/features/syscall.c
@@ -88,7 +88,7 @@ static void syscall_handler(struct regs *r)
 		} else {
 			// TODO: Reimplement argc,argv
 			proc_stack_push(proc, 0);
-			proc_yield();
+			proc_yield_regs(r);
 		}
 		break;
 	}
@@ -99,7 +99,7 @@ static void syscall_handler(struct regs *r)
 	}
 	case SYS_YIELD: {
 		r->eax = EOK;
-		proc_yield();
+		proc_yield_regs(r);
 		break;
 	}
 
diff --git a/kernel/inc/proc.h b/kernel/inc/proc.h
index e74286c..000d77d 100644
--- a/kernel/inc/proc.h
+++ b/kernel/inc/proc.h
@@ -60,6 +60,7 @@ u8 proc_idle(void);
 struct proc *proc_from_pid(u32 pid);
 void proc_exit(struct proc *proc, struct regs *r, s32 status) NONNULL;
 void proc_yield(void);
+void proc_yield_regs(struct regs *r) NONNULL;
 void proc_set_quantum(struct proc *proc, u32 value);
 void proc_reset_quantum(struct proc *proc);
 void proc_state(struct proc *proc, enum proc_state state);