From 2fa4193517c0dbafd181fe9d3a59091498712921 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Wed, 1 Nov 2023 21:22:54 -0400
Subject: [PATCH] Pass exception stack frame pointer to exception handler

Show exception stack frame contents on exception
---
 src/hulk/idt.d | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/src/hulk/idt.d b/src/hulk/idt.d
index 7902018..9a2a8d9 100644
--- a/src/hulk/idt.d
+++ b/src/hulk/idt.d
@@ -9,9 +9,21 @@ import hulk.fb;
 import hulk.console;
 import hulk.klog;
 import hulk.apic;
+import hulk.cpu;
 
 struct Idt
 {
+    static struct ExceptionStackFrame
+    {
+        ulong rip;
+        ulong cs;
+        ulong rflags;
+        ulong rsp;
+        ulong ss;
+    }
+
+    public static enum ulong EXC_PAGE_FAULT = 14;
+
     /* The I/O APIC is configured to map IRQ 0 to interrupt 64 (0x40). */
     public static enum ulong INT_APIC_BASE = 0x40u; /* IRQ 0 */
     public static enum ulong INT_APIC_COUNT = 24u;
@@ -74,10 +86,13 @@ struct Idt
                 pushq %rdi
                 pushq %rsi
                 pushq %rax
+                pushq %rdx
                 mov $$", isr, ", %rdi
-                " ~ (isr_has_error_code(isr) ? "mov 0x18(%rsp), %rsi" : "") ~ "
+                " ~ (isr_has_error_code(isr) ? "mov 0x20(%rsp), %rsi" : "") ~ "
+                " ~ (isr_has_error_code(isr) ? "lea 0x28(%rsp), %rdx" : "lea 0x20(%rsp), %rdx") ~ "
                 movabs $$isr, %rax
                 callq *%rax
+                popq %rdx
                 popq %rax
                 popq %rsi
                 popq %rdi
@@ -102,7 +117,7 @@ struct Idt
     }
 }
 
-public extern(C) void isr(ulong vector, ulong arg)
+public extern(C) void isr(ulong vector, ulong arg, Idt.ExceptionStackFrame * stack_frame)
 {
     if ((vector >= Idt.INT_APIC_BASE) && (vector < (Idt.INT_APIC_BASE + Idt.INT_APIC_COUNT)))
     {
@@ -122,7 +137,13 @@ public extern(C) void isr(ulong vector, ulong arg)
         default:
             Console.clear();
             Fb.clear(0xFF8000u);
-            Klog.writefln("ISR %u, 0x%x", vector, arg);
+            Klog.writefln("ISR %u, error code 0x%x", vector, arg);
+            Klog.writefln("RIP = 0x%p", stack_frame.rip);
+            Klog.writefln("CS = 0x%x", stack_frame.cs);
+            Klog.writefln("RFLAGS = 0x%x", stack_frame.rflags);
+            Klog.writefln("RSP = 0x%x", stack_frame.rsp);
+            Klog.writefln("SS = 0x%x", stack_frame.ss);
+            Klog.writefln("CR2 = 0x%p", read_cr2());
             __asm("cli", "");
             for (;;)
             {