1 files changed, 52 insertions, 3 deletions
diff --git a/kernel/head.S b/kernel/head.S
index ba155cb..de7852b 100644
--- a/kernel/head.S
+++ b/kernel/head.S
@@ -1,6 +1,55 @@
+#include <fbos/mm.h>
+
 .global _start
-.section .text.head
+.section .head.text
 
 _start:
-	// TODO
-	call start_kernel
+	// Mask all interrupts
+	csrw sie, zero
+	csrw sip, zero
+
+	// Flush the instruction cache
+	fence.i
+
+	// Reset all registers except ra, a0, a1.
+	li sp, 0
+	li gp, 0
+	li tp, 0
+	li t0, 0
+	li t1, 0
+	li t2, 0
+	li s0, 0
+	li s1, 0
+	li a2, 0
+	li a3, 0
+	li a4, 0
+	li a5, 0
+	li a6, 0
+	li a7, 0
+	li s2, 0
+	li s3, 0
+	li s4, 0
+	li s5, 0
+	li s6, 0
+	li s7, 0
+	li s8, 0
+	li s9, 0
+	li s10, 0
+	li s11, 0
+	li t3, 0
+	li t4, 0
+	li t5, 0
+	li t6, 0
+	csrw sscratch, 0
+
+	// Point tp and sp to the init task.
+	la tp, init_task
+	la sp, init_task + THREAD_SIZE
+
+	// The `start_kernel` function requires an argument to be passed, which is
+	// the pointer to the `fdt` blob. The bootloader puts this on the `a1`
+	// register, so let's move it now to `a0`.
+	mv a0, a1
+
+	// Start the kernel.
+	tail start_kernel