From d8b6105f36dbd69404ecdbf8cb99fe7f568ad404 Mon Sep 17 00:00:00 2001
From: Victor Cornille <victor.bolheme@gmail.com>
Date: Sun, 8 Sep 2024 20:53:03 +0200
Subject: [PATCH] + | syscall triggers GPF

---
 drivers/Makefile          | 11 +++++++++--
 drivers/syscall/syscall.c | 38 ++++++++++++++++++++++++++++++++++++++
 drivers/syscall/syscall.h |  9 +++++++++
 kernel/kernel.c           |  5 +++++
 kernel/kernel.h           |  1 +
 5 files changed, 62 insertions(+), 2 deletions(-)
 create mode 100644 drivers/syscall/syscall.c
 create mode 100644 drivers/syscall/syscall.h

diff --git a/drivers/Makefile b/drivers/Makefile
index 0460b25..a7040f9 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -6,6 +6,9 @@ VGA_OBJ	= vga/vga.o
 PIT_SRC	= pit/pit.c
 PIT_OBJ	= pit/pit.o
 
+SYS_SRC	= syscall/syscall.c
+SYS_OBJ	= syscall/syscall.o
+
 DES_SRC	= descriptor/idt.c descriptor/irq.c descriptor/isr.c descriptor/interrupt_handlers.s descriptor/gdt.c 
 DES_OBJ	= descriptor/idt.o descriptor/irq.o descriptor/isr.o descriptor/interrupt_handlers.o descriptor/gdt.o
 
@@ -21,12 +24,15 @@ FLAGS	= -ffreestanding	\
 
 all: $(DRIVERS)
 
-$(DRIVERS): $(VGA_OBJ) $(DES_OBJ) $(KEY_OBJ) $(PIT_OBJ)
-	$(AR) $@ $(VGA_OBJ) $(DES_OBJ) $(KEY_OBJ) $(PIT_OBJ)
+$(DRIVERS): $(VGA_OBJ) $(DES_OBJ) $(KEY_OBJ) $(PIT_OBJ) $(SYS_OBJ)
+	$(AR) $@ $(VGA_OBJ) $(DES_OBJ) $(KEY_OBJ) $(PIT_OBJ) $(SYS_OBJ)
 	
 $(VGA_OBJ): $(VGA_SRC)
 	$(CC) $(FLAGS) -c $^ -o $@
 
+$(SYS_OBJ): $(SYS_SRC)
+	$(CC) $(FLAGS) -c $^ -o $@
+
 $(PIT_OBJ): $(PIT_SRC)
 	$(CC) $(FLAGS) -c $^ -o $@
 
@@ -41,6 +47,7 @@ keyboard/%.o: keyboard/%.c
 
 clean:
 	rm -rf $(VGA_OBJ)
+	rm -rf $(SYS_OBJ)
 	rm -rf $(DES_OBJ)
 	rm -rf $(KEY_OBJ)
 	rm -rf $(PIT_OBJ)
diff --git a/drivers/syscall/syscall.c b/drivers/syscall/syscall.c
new file mode 100644
index 0000000..cee05b1
--- /dev/null
+++ b/drivers/syscall/syscall.c
@@ -0,0 +1,38 @@
+#include "syscall.h"
+
+void sys_read(registers_t* r) {
+	printf("Syscall read : eax == %d\n", r->eax);
+}
+
+void sys_write(registers_t* r) {
+	printf("Syscall write: eax == %d\n", r->eax);
+}
+
+void sys_open(registers_t* r) {
+	printf("Syscall open : eax == %d\n", r->eax);
+}
+
+void sys_close(registers_t* r) {
+	printf("Syscall close: eax == %d\n", r->eax);
+}
+
+void sys_stat(registers_t* r) {
+	printf("Syscall stat : eax == %d\n", r->eax);
+}
+
+isr_t syscall_tab[] = {
+	sys_read,
+	sys_write,
+	sys_open,
+	sys_close,
+	sys_stat
+	// Write all handlers here based on Linux system call table
+};
+
+void syscall_callback(registers_t* r) {
+	syscall_tab[r->eax](r);
+}
+
+void init_syscall() {
+	register_interrupt_handler(SYSCALL_INTERRUPT_NUMBER, &syscall_callback);
+}
diff --git a/drivers/syscall/syscall.h b/drivers/syscall/syscall.h
new file mode 100644
index 0000000..8414fd1
--- /dev/null
+++ b/drivers/syscall/syscall.h
@@ -0,0 +1,9 @@
+#ifndef SYSCALL_H
+# define SYSCALL_H
+
+#include "../descriptor/descriptor.h"
+
+# define SYSCALL_INTERRUPT_NUMBER 0x80
+void init_syscall();
+
+#endif
diff --git a/kernel/kernel.c b/kernel/kernel.c
index 7680c37..b65bcc0 100644
--- a/kernel/kernel.c
+++ b/kernel/kernel.c
@@ -37,6 +37,11 @@ void	kernel_main(uint32_t magic, uint32_t addr) {
     isr_install();
     init_keyboard();
     init_timer(50);
+    init_syscall();
+    asm volatile(
+	"mov $1, %eax\n"
+	"int $80"
+    );
     pmm_init(mem_size, bitmap);
 
     for (size_t i = 0; i < 15; i++) {
diff --git a/kernel/kernel.h b/kernel/kernel.h
index 3957071..3dd41d0 100644
--- a/kernel/kernel.h
+++ b/kernel/kernel.h
@@ -7,6 +7,7 @@
 #include "../drivers/descriptor/descriptor.h"
 #include "../drivers/keyboard/keyboard.h"
 #include "../drivers/pit/pit.h"
+#include "../drivers/syscall/syscall.h"
 #include "../multiboot/multiboot.h"
 #include "../memory/pmm/pmm.h"
 #include "../memory/vmm/vmm.h"