5 files changed, 57 insertions, 1 deletions

diff --git a/kernel/src/sys/syscall.S b/kernel/src/sys/syscall.S
deleted file mode 100644
index e69de29..0000000
--- a/kernel/src/sys/syscall.S
+++ /dev/null
diff --git a/kernel/src/sys/syscall.c b/kernel/src/sys/syscall.c
new file mode 100644
index 0000000..7f0e492
--- /dev/null
+++ b/kernel/src/sys/syscall.c
@@ -0,0 +1,9 @@
+#include <libk/stdio.h>
+#include <syscall.h>
+
+void syscall_handler()
+{
+	uint64_t rax;
+	__asm__ volatile ("mov %%rax, %0;" : "=r"(rax) : :);
+	printf("syscall invoked with rax=0x%x\n", rax);
+}
diff --git a/kernel/src/sys/syscall_asm.S b/kernel/src/sys/syscall_asm.S
new file mode 100644
index 0000000..a9942ca
--- /dev/null
+++ b/kernel/src/sys/syscall_asm.S
@@ -0,0 +1,40 @@
+.extern syscall_handler
+
+.macro pushall
+	push %rax
+	push %rcx
+	push %rdx
+	push %rsi
+	push %rdi
+	push %r8
+	push %r9
+	push %r10
+	push %r11
+	pushfq
+.endm
+
+.macro popall
+	popfq
+	pop %r11
+	pop %r10
+	pop %r9
+	pop %r8
+	pop %rdi
+	pop %rsi
+	pop %rdx
+	pop %rcx
+	pop %rax
+.endm
+
+.global __syscall
+__syscall:
+	pushq %rcx
+	pushq %r11
+
+	pushall
+	call syscall_handler
+	popall
+
+	popfq
+	popq %rcx
+	sysretq
diff --git a/kernel/src/sys/userspace.c b/kernel/src/sys/userspace.c
index 4add4d5..111180a 100644
--- a/kernel/src/sys/userspace.c
+++ b/kernel/src/sys/userspace.c
@@ -3,7 +3,9 @@
 
 void begin_userspace()
 {
+	__asm__ volatile ("mov $0x1, %rax; syscall;");
+	__asm__ volatile ("mov $0x11, %rax; syscall;");
+	__asm__ volatile ("mov $0x111, %rax; syscall;");
 	while(true) {
-
 	}
 }
diff --git a/kernel/src/sys/userspace_asm.S b/kernel/src/sys/userspace_asm.S
index c722df0..5817a8c 100644
--- a/kernel/src/sys/userspace_asm.S
+++ b/kernel/src/sys/userspace_asm.S
@@ -1,6 +1,7 @@
 .text
 
 .extern begin_userspace
+.extern syscall_handler
 
 .global jump_userspace
 jump_userspace:
@@ -11,6 +12,10 @@ jump_userspace:
 	mov %ax, %gs
 
 	mov $0xc0000082, %rcx
+	movabs $__syscall, %rax
+	shr $32, %rax
+	mov %eax, %edx
+	movabs $__syscall, %rax
 	wrmsr
 	mov $0xc0000080, %rcx
 	rdmsr