Working userspace!

18 files changed, 196 insertions, 391 deletions

diff --git a/Makefile b/Makefile
index d155efc..0d5d541 100644
--- a/Makefile
+++ b/Makefile
@@ -19,7 +19,7 @@ build: clean
 	nasm -f elf ./src/kernel/boot.asm -o ./build/boot.o || exit; \
 
 	# Make all C files
-	find ./src/kernel/ ./src/userspace/ ./src/mlibc/ -name \*.c >./build/tmp; \
+	find ./src/kernel/ ./src/mlibc/ -name \*.c >./build/tmp; \
 	while read -r line; do \
 		stripped=$$(echo "$${line}" | sed -r 's/\//_/g'); \
 		stripped=$${stripped#??????}; \
@@ -40,6 +40,7 @@ build: clean
 	nasm ./src/bootloader/cd.asm -f bin -o ./iso/boot/cd.bin || exit; \
 	nasm ./src/bootloader/hdd1.asm -f bin -o ./iso/boot/hdd1.bin || exit; \
 	nasm ./src/bootloader/hdd2.asm -f bin -o ./iso/boot/hdd2.bin || exit; \
+	nasm ./src/userspace/main.asm -f bin -o ./iso/user.bin || exit; \
 	cp ./build/font.bin ./iso/font.bin || exit; \
 	genisoimage -quiet -input-charset utf-8 -no-emul-boot -b boot/cd.bin -o ./build/melvix.iso ./iso;
 
diff --git a/src/kernel/boot.asm b/src/kernel/boot.asm
index 28e3c38..fc5a859 100644
--- a/src/kernel/boot.asm
+++ b/src/kernel/boot.asm
@@ -36,10 +36,10 @@ section .text
 
     %include "src/kernel/interact.asm"
 
-    global switch_to_user
-    extern test_user
-    switch_to_user:
-        sti
+    global jump_userspace
+    jump_userspace:
+        mov ebx, dword [esp+4]
+
         mov ax, 0x23
         mov ds, ax
         mov es, ax
@@ -50,8 +50,10 @@ section .text
         push 0x23
         push eax
         pushf
+
         push 0x1B
-        push test_user
+        push ebx
+        mov ebp, ebx
         iret
 
 section .end_section
diff --git a/src/kernel/fs/install.c b/src/kernel/fs/install.c
index 4df1f7f..358bd98 100644
--- a/src/kernel/fs/install.c
+++ b/src/kernel/fs/install.c
@@ -50,7 +50,7 @@ void install_melvix()
     kfree(stage2_e);
 
     // Copy the kernel
-    info("Copying the kernel... ");
+    info("Copying the kernel...");
     char *kernel_p[] = {"BOOT", "KERNEL.BIN"};
     struct iso9660_entity *kernel_e = ISO9660_get(kernel_p, 2);
     if (!kernel_e)
@@ -61,6 +61,17 @@ void install_melvix()
     kfree(kernel);
     kfree(kernel_e);
 
+    // Copy the userspace binary
+    info("Copying userspace... ");
+    char *userspace_p[] = {"USER.BIN"};
+    struct iso9660_entity *userspace_e = ISO9660_get(userspace_p, 1);
+    if (!userspace_e)
+        panic("Userspace not found!");
+    uint8_t *userspace = ISO9660_read(userspace_e);
+    marfs_new_file(userspace_e->length, userspace, 0, 0, 0);
+    kfree(userspace_e);
+
+    // Copy the global font binary
     info("Copying font... ");
     char *font_p[] = {"FONT.BIN"};
     struct iso9660_entity *font_e = ISO9660_get(font_p, 1);
@@ -77,4 +88,5 @@ void install_melvix()
     serial_write("Installation successful!\nRebooting...\n");
     timer_wait(200);
     acpi_poweroff();
+    halt_loop();
 }
\ No newline at end of file
diff --git a/src/kernel/gdt/gdt.asm b/src/kernel/gdt/gdt.asm
index 6cb2b7d..51ce444 100644
--- a/src/kernel/gdt/gdt.asm
+++ b/src/kernel/gdt/gdt.asm
@@ -9,12 +9,6 @@ gdt_flush:
     mov fs, ax
     mov gs, ax
     mov ss, ax
-    jmp 0x08:flush2 ; Code segment offset
-flush2:
-    ret ; Returns to C code
-
-global tss_flush
-tss_flush:
-    mov ax, 0x2B
-    ltr ax
-    ret
\ No newline at end of file
+    jmp 0x08:flush ; Code segment offset
+flush:
+    ret ; Returns to C code
\ No newline at end of file
diff --git a/src/kernel/gdt/gdt.c b/src/kernel/gdt/gdt.c
index 70d5b7f..94ce06b 100644
--- a/src/kernel/gdt/gdt.c
+++ b/src/kernel/gdt/gdt.c
@@ -2,7 +2,7 @@
 #include <kernel/gdt/gdt.h>
 #include <kernel/system.h>
 #include <kernel/lib/lib.h>
-#include <kernel/io/io.h>
+#include <mlibc/stdlib/liballoc.h>
 
 struct gdt_entry {
     unsigned short limit_low;
@@ -55,8 +55,6 @@ struct tss_entry_struct tss_entry;
 
 extern void gdt_flush();
 
-extern void tss_flush();
-
 void gdt_set_gate(int32_t num, uint32_t base, uint32_t limit, uint8_t access, uint8_t gran)
 {
     // Set descriptor base address
@@ -95,32 +93,31 @@ void gdt_install()
     gdt_set_gate(4, 0, 0xFFFFFFFF, 0xF2, 0xCF);
 
     // Write TSS
-    tss_write(5, 0x10, 0x0);
+    tss_write(5, 0x10);
 
     // Remove old GDT and install the new changes!
     gdt_flush();
-    tss_flush();
 
     vga_log("Installed Global Descriptor Table", 1);
 }
 
-void tss_write(int32_t num, uint16_t ss0, uint32_t esp0)
+void tss_write(int32_t num, uint16_t ss0)
 {
     uint32_t base = (uint32_t) &tss_entry;
-    uint32_t limit = base + sizeof(tss_entry);
+    uint32_t limit = base + sizeof(struct tss_entry_struct);
 
     gdt_set_gate(num, base, limit, 0xE9, 0x00);
 
     memset(&tss_entry, 0, sizeof(tss_entry));
 
     tss_entry.ss0 = ss0;
-    tss_entry.esp0 = esp0;
-
+    tss_entry.iomap_base = sizeof(struct tss_entry_struct);
     tss_entry.cs = 0x0b;
     tss_entry.ss = tss_entry.ds = tss_entry.es = tss_entry.fs = tss_entry.gs = 0x13;
 }
 
-void set_kernel_stack(uint32_t stack)
+void tss_flush(void)
 {
-    tss_entry.esp0 = stack;
-}
+    tss_entry.esp0 = 4096 + (uint32_t) kmalloc(4096);
+    asm volatile ("ltr %%ax": : "a" (0x2A));
+}
\ No newline at end of file
diff --git a/src/kernel/gdt/gdt.h b/src/kernel/gdt/gdt.h
index 0fffc20..da36445 100644
--- a/src/kernel/gdt/gdt.h
+++ b/src/kernel/gdt/gdt.h
@@ -6,6 +6,8 @@
  */
 void gdt_install();
 
-void tss_write(int32_t num, uint16_t ss0, uint32_t esp0);
+void tss_write(int32_t num, uint16_t ss0);
+
+void tss_flush();
 
 #endif
diff --git a/src/kernel/graphics/font.c b/src/kernel/graphics/font.c
index a7e5096..458669b 100644
--- a/src/kernel/graphics/font.c
+++ b/src/kernel/graphics/font.c
@@ -16,7 +16,7 @@ void font_install()
     if (boot_drive_id != 0xE0) {
         struct ata_interface *primary_master = new_ata(1, 0x1F0);
         marfs_init(primary_master);
-        marfs_read_whole_file(4, (uint8_t *) font);
+        marfs_read_whole_file(5, (uint8_t *) font);
     } else {
         char *font_p[] = {"FONT.BIN"};
         struct iso9660_entity *font_e = ISO9660_get(font_p, 1);
diff --git a/src/kernel/interrupts/idt.asm b/src/kernel/interrupts/idt.asm
index 90eab47..f30ead1 100644
--- a/src/kernel/interrupts/idt.asm
+++ b/src/kernel/interrupts/idt.asm
@@ -4,3 +4,38 @@ extern idtp
 idt_load:
     lidt [idtp]
     ret
+
+global idt_syscall
+extern syscall_handler
+idt_syscall:
+    push ds
+    push es
+    push fs
+    push gs
+    pushad
+
+    push ecx
+    push edx
+    push esi
+    push edi
+    push eax
+
+    mov ax, 0x10
+    mov ds, ax
+    mov es, ax
+    mov fs, ax
+    mov gs, ax
+
+    call syscall_handler
+
+    lea ebx, [5 * 4]
+    add esp, ebx
+
+    mov dword [esp + (7*4)], eax
+
+    popad
+    pop gs
+    pop fs
+    pop es
+    pop ds
+    iret
diff --git a/src/kernel/interrupts/idt.c b/src/kernel/interrupts/idt.c
index b06a52a..f405ca9 100644
--- a/src/kernel/interrupts/idt.c
+++ b/src/kernel/interrupts/idt.c
@@ -2,11 +2,11 @@
 #include <kernel/system.h>
 
 struct idt_entry {
-    unsigned short base_lo;
-    unsigned short sel; // Kernel segment
-    unsigned char always0; // Always 0
-    unsigned char flags;
-    unsigned short base_hi;
+    uint16_t base_low;
+    uint16_t sel; // Kernel segment
+    uint8_t always0; // Always 0
+    uint8_t flags;
+    uint16_t base_high;
 } __attribute__((packed));
 
 struct idt_ptr {
@@ -24,13 +24,13 @@ extern void idt_load();
 void idt_set_gate(unsigned char num, unsigned long base, unsigned short sel, unsigned char flags)
 {
     // Specify the interrupt routine's base address
-    idt[num].base_lo = (base & 0xFFFF);
-    idt[num].base_hi = (base >> 16) & 0xFFFF;
+    idt[num].base_low = (base & 0xFFFF);
+    idt[num].base_high = (base >> 16) & 0xFFFF;
 
     // Set selector/segment of IDT entry
     idt[num].sel = sel;
     idt[num].always0 = 0;
-    idt[num].flags = flags;
+    idt[num].flags = flags | 0x60;
 }
 
 // Install IDT
diff --git a/src/kernel/interrupts/isr.asm b/src/kernel/interrupts/isr.asm
index cf75157..adabac6 100644
--- a/src/kernel/interrupts/isr.asm
+++ b/src/kernel/interrupts/isr.asm
@@ -1,277 +1,74 @@
-global isr0
-global isr1
-global isr2
-global isr3
-global isr4
-global isr5
-global isr6
-global isr7
-global isr8
-global isr9
-global isr10
-global isr11
-global isr12
-global isr13
-global isr14
-global isr15
-global isr16
-global isr17
-global isr18
-global isr19
-global isr20
-global isr21
-global isr22
-global isr23
-global isr24
-global isr25
-global isr26
-global isr27
-global isr28
-global isr29
-global isr30
-global isr31
-
-; 0: Divide By Zero Exception
-isr0:
-    cli
-    push byte 0
-    push byte 0
-    jmp isr_common_stub
-
-; 1: Debug Exception
-isr1:
-    cli
-    push byte 0
-    push byte 1
-    jmp isr_common_stub
-
-; 2: Non Maskable Interrupt Exception
-isr2:
-    cli
-    push byte 0
-    push byte 2
-    jmp isr_common_stub
-
-; 3: Int 3 Exception
-isr3:
-    cli
-    push byte 0
-    push byte 3
-    jmp isr_common_stub
-
-; 4: INTO Exception
-isr4:
-    cli
-    push byte 0
-    push byte 4
-    jmp isr_common_stub
-
-; 5: Out of Bounds Exception
-isr5:
-    cli
-    push byte 0
-    push byte 5
-    jmp isr_common_stub
-
-; 6: Invalid Opcode Exception
-isr6:
-    cli
-    push byte 0
-    push byte 6
-    jmp isr_common_stub
-
-; 7: Coprocessor Not Available Exception
-isr7:
-    cli
-    push byte 0
-    push byte 7
-    jmp isr_common_stub
-
-; 8: Double Fault Exception (With Error Code!)
-isr8:
-    cli
-    push byte 8
-    jmp isr_common_stub
-
-; 9: Coprocessor Segment Overrun Exception
-isr9:
-    cli
-    push byte 0
-    push byte 9
-    jmp isr_common_stub
-
-; 10: Bad TSS Exception (With Error Code!)
-isr10:
-    cli
-    push byte 10
-    jmp isr_common_stub
-
-; 11: Segment Not Present Exception (With Error Code!)
-isr11:
-    cli
-    push byte 11
-    jmp isr_common_stub
-
-; 12: Stack Fault Exception (With Error Code!)
-isr12:
-    cli
-    push byte 12
-    jmp isr_common_stub
-
-; 13: General Protection Fault Exception (With Error Code!)
-isr13:
-    cli
-    push byte 13
-    jmp isr_common_stub
-
-; 14: Page Fault Exception (With Error Code!)
-isr14:
-    cli
-    push byte 14
-    jmp isr_common_stub
-
-; 15: Reserved Exception
-isr15:
-    cli
-    push byte 0
-    push byte 15
-    jmp isr_common_stub
-
-; 16: Floating Point Exception
-isr16:
-    cli
-    push byte 0
-    push byte 16
-    jmp isr_common_stub
-
-; 17: Alignment Check Exception
-isr17:
-    cli
-    push byte 0
-    push byte 17
-    jmp isr_common_stub
-
-; 18: Machine Check Exception
-isr18:
-    cli
-    push byte 0
-    push byte 18
-    jmp isr_common_stub
-
-; 19: Reserved
-isr19:
-    cli
-    push byte 0
-    push byte 19
-    jmp isr_common_stub
-
-; 20: Reserved
-isr20:
-    cli
-    push byte 0
-    push byte 20
-    jmp isr_common_stub
-
-; 21: Reserved
-isr21:
-    cli
-    push byte 0
-    push byte 21
-    jmp isr_common_stub
-
-; 22: Reserved
-isr22:
-    cli
-    push byte 0
-    push byte 22
-    jmp isr_common_stub
-
-; 23: Reserved
-isr23:
-    cli
-    push byte 0
-    push byte 23
-    jmp isr_common_stub
-
-; 24: Reserved
-isr24:
-    cli
-    push byte 0
-    push byte 24
-    jmp isr_common_stub
-
-; 25: Reserved
-isr25:
-    cli
-    push byte 0
-    push byte 25
-    jmp isr_common_stub
-
-; 26: Reserved
-isr26:
-    cli
-    push byte 0
-    push byte 26
-    jmp isr_common_stub
-
-; 27: Reserved
-isr27:
-    cli
-    push byte 0
-    push byte 27
-    jmp isr_common_stub
-
-; 28: Reserved
-isr28:
-    cli
-    push byte 0
-    push byte 28
-    jmp isr_common_stub
-
-; 29: Reserved
-isr29:
-    cli
-    push byte 0
-    push byte 29
-    jmp isr_common_stub
-
-; 30: Reserved
-isr30:
-    cli
-    push byte 0
-    push byte 30
-    jmp isr_common_stub
-
-; 31: Reserved
-isr31:
-    cli
-    push byte 0
-    push byte 31
-    jmp isr_common_stub
+%macro ISR_NOERRCODE 1
+    global isr%1
+    isr%1:
+        cli
+        push byte 0
+        push %1
+        jmp isr_common_stub
+%endmacro
+
+%macro ISR_ERRCODE 1
+    global isr%1
+    isr%1:
+        cli
+        push byte %1
+        jmp isr_common_stub
+%endmacro
+
+ISR_NOERRCODE 0
+ISR_NOERRCODE 1
+ISR_NOERRCODE 2
+ISR_NOERRCODE 3
+ISR_NOERRCODE 4
+ISR_NOERRCODE 5
+ISR_NOERRCODE 6
+ISR_NOERRCODE 7
+ISR_ERRCODE   8
+ISR_NOERRCODE 9
+ISR_ERRCODE   10
+ISR_ERRCODE   11
+ISR_ERRCODE   12
+ISR_ERRCODE   13
+ISR_ERRCODE   14
+ISR_NOERRCODE 15
+ISR_NOERRCODE 16
+ISR_NOERRCODE 17
+ISR_NOERRCODE 18
+ISR_NOERRCODE 19
+ISR_NOERRCODE 20
+ISR_NOERRCODE 21
+ISR_NOERRCODE 22
+ISR_NOERRCODE 23
+ISR_NOERRCODE 24
+ISR_NOERRCODE 25
+ISR_NOERRCODE 26
+ISR_NOERRCODE 27
+ISR_NOERRCODE 28
+ISR_NOERRCODE 29
+ISR_NOERRCODE 30
+ISR_NOERRCODE 31
 
 extern fault_handler
-
-; Stores the ISR in the stack and calls the C fault handler
 isr_common_stub:
-    pusha
-    push ds
+push ds
     push es
     push fs
-    push gs
-    mov ax, 0x10
-    mov ds, ax
-    mov es, ax
-    mov fs, ax
-    mov gs, ax
-    mov eax, esp
-    push eax
-    mov eax, fault_handler
-    call eax
-    pop eax
-    pop gs
+	push gs
+	pusha
+
+	mov ax, 0x10
+	mov ds, ax
+	mov es, ax
+	mov fs, ax
+	mov gs, ax
+
+	push esp
+	call fault_handler
+	add esp, 4
+
+	popa
+	pop gs
     pop fs
     pop es
-    pop ds
-    popa
-    add esp, 8
-    iret
+	pop ds
+	iret
\ No newline at end of file
diff --git a/src/kernel/interrupts/isr.c b/src/kernel/interrupts/isr.c
index 8b42a24..106cac8 100644
--- a/src/kernel/interrupts/isr.c
+++ b/src/kernel/interrupts/isr.c
@@ -170,6 +170,8 @@ void fault_handler(struct regs *r)
         serial_write_hex(r->ecx);
         serial_write("\nEDX: ");
         serial_write_hex(r->edx);
+        serial_write("\nESP: ");
+        serial_write_hex(r->esp);
         serial_write("\nFaulting address: ");
         serial_write_hex(faulting_address);
         serial_write("\nError flags: ");
@@ -180,7 +182,7 @@ void fault_handler(struct regs *r)
         serial_write_hex(r->int_no);
         serial_write("\nInterrupt message: ");
         serial_write(exception_messages[r->int_no]);
-        halt_loop(); // Idk loop?
+        // halt_loop(); // Idk loop?
         char *message = (char *) exception_messages[r->int_no];
         strcat(message, " Exception");
         panic(message);
diff --git a/src/kernel/kernel.c b/src/kernel/kernel.c
index ef58ade..eb78257 100644
--- a/src/kernel/kernel.c
+++ b/src/kernel/kernel.c
@@ -6,13 +6,13 @@
 #include <kernel/paging/paging.h>
 #include <kernel/input/input.h>
 #include <kernel/acpi/acpi.h>
-#include <kernel/syscall/syscall.h>
 #include <kernel/smbios/smbios.h>
 #include <kernel/fs/install.h>
 #include <kernel/lib/lib.h>
-#include <mlibc/stdio.h>
+#include <kernel/syscall/syscall.h>
+#include <kernel/fs/marfs/marfs.h>
 
-extern void switch_to_user();
+extern void jump_userspace();
 
 void kernel_main()
 {
@@ -41,21 +41,22 @@ void kernel_main()
     get_smbios();
 
     // Print total memory
-    info("Total memory found: %dMiB", memory_get_all() >> 10);
+    info("Total memory found: %dMiB", (memory_get_all() >> 10) + 1);
 
     uint8_t boot_drive_id = (uint8_t) (*((uint8_t *) 0x9000));
-    if (boot_drive_id == 0xE0) {
+    if (boot_drive_id == 0xE0)
         install_melvix();
-    }
 
     // User mode!
-    /* COMMENTED FOR DEVELOPMENT OF KERNEL
     info("Switching to user mode...");
     syscalls_install();
-    switch_to_user();
+    tss_flush();
+    uint32_t userspace = paging_alloc_pages(2);
+    paging_set_user(userspace, 2);
+    marfs_read_whole_file(4, (uint8_t *) (userspace + 4096));
+    jump_userspace(userspace + 4096);
 
     panic("This should NOT happen!");
-    */
 
     // asm ("div %0" :: "r"(0)); // Exception testing x/0
     loop:
diff --git a/src/kernel/syscall/actions/sys_write.c b/src/kernel/syscall/actions/sys_write.c
new file mode 100644
index 0000000..c537d12
--- /dev/null
+++ b/src/kernel/syscall/actions/sys_write.c
@@ -0,0 +1,9 @@
+#include <stdint-gcc.h>
+#include <mlibc/stdio.h>
+
+uint32_t sys_write(char *buf, uint32_t count)
+{
+    for (uint32_t i = 0; i < count; i++)
+        writec(*(buf++));
+    return count;
+}
\ No newline at end of file
diff --git a/src/kernel/syscall/syscall.c b/src/kernel/syscall/syscall.c
index 5acd525..289274b 100644
--- a/src/kernel/syscall/syscall.c
+++ b/src/kernel/syscall/syscall.c
@@ -1,42 +1,19 @@
 #include <stdint.h>
 #include <kernel/syscall/syscall.h>
 #include <kernel/interrupts/interrupts.h>
-#include <kernel/graphics/vesa.h>
-#include <kernel/io/io.h>
 
-DEFN_SYSCALL1(serial_write, 0, const char *);
-
-static void *syscalls[3] = {
-        &serial_write
-};
-uint32_t num_syscalls = 3;
-
-void syscall_handler(struct regs *r)
+void syscalls_install()
 {
-    serial_write("SYSCALL");
-    if (r->eax >= num_syscalls)
-        return;
-
-    void *location = syscalls[r->eax];
-
-    int ret;
-    asm (" \
-     push %1; \
-     push %2; \
-     push %3; \
-     push %4; \
-     push %5; \
-     call *%6; \
-     pop %%ebx; \
-     pop %%ebx; \
-     pop %%ebx; \
-     pop %%ebx; \
-     pop %%ebx; \
-   " : "=a" (ret) : "r" (r->edi), "r" (r->esi), "r" (r->edx), "r" (r->ecx), "r" (r->ebx), "r" (location));
-    r->eax = ret;
+    // 11100111
+    idt_set_gate(0x80, (unsigned) idt_syscall, 0x08, 0xEE);
 }
 
-void syscalls_install()
+uint32_t syscall_handler(uint32_t id, uint32_t arg0, uint32_t arg1, uint32_t arg2)
 {
-    irq_install_handler(0x80, syscall_handler);
-}
+    switch (id) {
+        case 1:
+            return sys_write((char *) arg0, arg1);
+    }
+
+    return -1;
+}
\ No newline at end of file
diff --git a/src/kernel/syscall/syscall.h b/src/kernel/syscall/syscall.h
index 78a1ab5..7fe7862 100644
--- a/src/kernel/syscall/syscall.h
+++ b/src/kernel/syscall/syscall.h
@@ -1,40 +1,9 @@
 #ifndef MELVIX_SYSCALL_H
 #define MELVIX_SYSCALL_H
 
-#include <kernel/interrupts/interrupts.h>
-
+extern void idt_syscall();
 void syscalls_install();
 
-void syscall_handler(struct regs *r);
-
-#define DECL_SYSCALL0(fn) int syscall_##fn();
-#define DECL_SYSCALL1(fn, p1) int syscall_##fn(p1);
-#define DECL_SYSCALL2(fn, p1, p2) int syscall_##fn(p1,p2);
-#define DECL_SYSCALL3(fn, p1, p2, p3) int syscall_##fn(p1,p2,p3);
-#define DECL_SYSCALL4(fn, p1, p2, p3, p4) int syscall_##fn(p1,p2,p3,p4);
-#define DECL_SYSCALL5(fn, p1, p2, p3, p4, p5) int syscall_##fn(p1,p2,p3,p4,p5);
-
-#define DEFN_SYSCALL0(fn, num) \
-int syscall_##fn() { \
- int a; \
- asm volatile("int $0x80" : "=a" (a) : "0" (num)); \
- return a; \
-}
-
-#define DEFN_SYSCALL1(fn, num, P1) \
-int syscall_##fn(P1 p1) { \
- int a; \
- asm volatile("int $0x80" : "=a" (a) : "0" (num), "b" ((int)p1)); \
- return a; \
-}
-
-#define DEFN_SYSCALL2(fn, num, P1, P2) \
-int syscall_##fn(P1 p1, P2 p2) { \
- int a; \
- asm volatile("int $0x80" : "=a" (a) : "0" (num), "b" ((int)p1), "c" ((int)p2)); \
- return a; \
-}
-
-DECL_SYSCALL1(serial_write, const char *)
+uint32_t sys_write(char *buf, uint32_t count);
 
 #endif
diff --git a/src/kernel/system.c b/src/kernel/system.c
index c5cf4ce..7d57f66 100644
--- a/src/kernel/system.c
+++ b/src/kernel/system.c
@@ -106,6 +106,7 @@ void assert(int x)
 void halt_loop()
 {
     serial_write("\n!!! HALT !!!\n");
+    asm ("cli");
     loop:
     asm ("hlt");
     goto loop;
diff --git a/src/userspace/main.asm b/src/userspace/main.asm
new file mode 100644
index 0000000..4369f10
--- /dev/null
+++ b/src/userspace/main.asm
@@ -0,0 +1,12 @@
+bits 32
+mov esp, ebp
+
+mov eax, 1
+lea edi, [ebp+welcome]
+mov esi, welcome_sz
+int 0x80
+
+jmp $
+
+welcome db "Welcome to the userspace!", 0x0A, 0x0A
+welcome_sz equ $ - welcome
\ No newline at end of file
diff --git a/src/userspace/main.c b/src/userspace/main.c
deleted file mode 100644
index 73e937f..0000000
--- a/src/userspace/main.c
+++ /dev/null
@@ -1,6 +0,0 @@
-#include <kernel/syscall/syscall.h>
-
-void test_user()
-{
-    syscall_serial_write("Hello, user world!\n");
-}
\ No newline at end of file