amd64: barely boot into kernel code

1 files changed, 13 insertions, 0 deletions

diff --git a/src/kernel/arch/amd64/boot64.s b/src/kernel/arch/amd64/boot64.s
new file mode 100644
index 0000000..1dca0ca
--- /dev/null
+++ b/src/kernel/arch/amd64/boot64.s
@@ -0,0 +1,13 @@
+.global boot64
+boot64:
+	lgdt (lgdt_arg) // try reloading gdt again
+	mov $(5 << 3 | 3), %ax // SEG_TSS
+	ltr %ax
+
+	xchgw %bx, %bx
+	push %rdi // preserve multiboot struct
+	call sysenter_setup
+	pop %rdi
+
+	// multiboot struct in %rdi
+	jmp kmain_early