From 7f91fd1fea9cb58d34022561fb799073a538d107 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@mirocom.org>
Date: Fri, 17 Apr 2026 14:39:33 -0400
Subject: [PATCH] sp1/amd64: cpu: Add interrupt descriptor table

Signed-off-by: Ian Moffett <ian@mirocom.org>
---
 usr/src/sp1/amd64/cpu/cpu_idt.c  | 47 +++++++++++++++++++++++
 usr/src/sp1/amd64/cpu/cpu_init.c |  4 ++
 usr/src/sp1/head/amd64/idt.h     | 65 ++++++++++++++++++++++++++++++++
 3 files changed, 116 insertions(+)
 create mode 100644 usr/src/sp1/amd64/cpu/cpu_idt.c
 create mode 100644 usr/src/sp1/head/amd64/idt.h

diff --git a/usr/src/sp1/amd64/cpu/cpu_idt.c b/usr/src/sp1/amd64/cpu/cpu_idt.c
new file mode 100644
index 0000000..4b2fb3c
--- /dev/null
+++ b/usr/src/sp1/amd64/cpu/cpu_idt.c
@@ -0,0 +1,47 @@
+
+/*
+ * Copyright (c) 2026, Mirocom Laboratories
+ * All rights reserved.
+ *
+ * The following sources are CONFIDENTIAL and PROPRIETARY
+ * property of Mirocom Laboratories. Unauthorized copying,
+ * use, distribution or modification of this file, in whole
+ * and in part, is strictly prohibited without the prior written
+ * consent from Mirocom Laboratories.
+ */
+
+#include <sys/types.h>
+#include <sys/cdefs.h>
+#include <machine/idt.h>
+#include <machine/gdt.h>
+
+__align(8) static struct idt_gate idt[256];
+static struct idtr idtr = {
+    .limit = sizeof(idt) - 1,
+    .base = (uintptr_t)&idt[0]
+};
+
+void
+md_idt_set_gate(uint8_t vector, uintptr_t isr, uint8_t type, uint8_t ist)
+{
+    struct idt_gate *gate;
+
+    gate = &idt[vector];
+    gate->offset_low   = (isr & 0xFFFF);
+    gate->offset_mid   = (isr >> 16) & 0xFFFF;
+    gate->offset_high  = (isr >> 32) & 0xFFFFFFFF;
+    gate->p = 1;
+    gate->dpl = (type == IDT_USER_GATE) ? 3 : 0;
+    gate->zero = 0;
+    gate->zero1 = 0;
+    gate->reserved = 0;
+    gate->type = type;
+    gate->ist = ist;
+    gate->segment_sel = GDT_KCODE;
+}
+
+void
+md_idt_load(void)
+{
+    __asmv("lidt %0" :: "m" (idtr) : "memory");
+}
diff --git a/usr/src/sp1/amd64/cpu/cpu_init.c b/usr/src/sp1/amd64/cpu/cpu_init.c
index 99267f2..a54bf37 100644
--- a/usr/src/sp1/amd64/cpu/cpu_init.c
+++ b/usr/src/sp1/amd64/cpu/cpu_init.c
@@ -12,6 +12,7 @@
 #include <mu/cpu.h>
 #include <lib/printf.h>
 #include <machine/cpuid.h>
+#include <machine/idt.h>
 #include <stdbool.h>
 
 #define pr_trace(fmt, ...) \
@@ -87,4 +88,7 @@ mu_cpu_preinit(struct cpu_info *ci)
 
     /* Log out some information */
     cpu_print_info(ci);
+
+    /* Load the IDT */
+    md_idt_load();
 }
diff --git a/usr/src/sp1/head/amd64/idt.h b/usr/src/sp1/head/amd64/idt.h
new file mode 100644
index 0000000..3dba727
--- /dev/null
+++ b/usr/src/sp1/head/amd64/idt.h
@@ -0,0 +1,65 @@
+/* Copyright (c) 2026, Mirocom Laboratories
+ * All rights reserved.
+ *
+ * The following sources are CONFIDENTIAL and PROPRIETARY
+ * property of Mirocom Laboratories. Unauthorized copying,
+ * use, distribution or modification of this file, in whole
+ * and in part, is strictly prohibited without the prior written
+ * consent from Mirocom Laboratories.
+ */
+
+#ifndef _MACHINE_IDT_H_
+#define _MACHINE_IDT_H_ 1
+
+#ifndef __ASSEMBLER__
+#include <sys/types.h>
+#include <sys/cdefs.h>
+#endif  /* !__ASSEMBLER__ */
+
+#define IDT_INT_GATE    0x8E
+#define IDT_TRAP_GATE   0x8F
+#define IDT_USER_GATE   0xEE
+
+#ifndef __ASSEMBLER__
+/*
+ * 64-bit interrupt gate descriptor
+ */
+struct idt_gate {
+    uint16_t offset_low;
+    uint16_t segment_sel;
+    uint8_t ist   : 3;
+    uint8_t zero  : 5;
+    uint8_t type  : 4;
+    uint8_t zero1 : 1;
+    uint8_t dpl   : 2;
+    uint8_t p     : 1;
+    uint16_t offset_mid;
+    uint32_t offset_high;
+    uint32_t reserved;
+};
+
+/*
+ * Points to
+ */
+struct __packed idtr {
+    uint16_t  limit;
+    uintptr_t base;
+};
+
+/*
+ * Set an IDT gate desriptor
+ *
+ * @vector: Interrupt vector to set
+ * @isr:    Interrupt service routine base
+ * @type:   Gate descriptor type
+ * @ist:    Interrupt stack table index
+ */
+void md_idt_set_gate(uint8_t vector, uintptr_t isr, uint8_t type, uint8_t ist);
+
+/*
+ * Load the IDT
+ */
+void md_idt_load(void);
+
+#endif  /* !__ASSEMBLER__ */
+#endif  /* !_MACHINE_IDT_H_ */