From 9566dac198f685ef947d82facee0be182a77495e Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Fri, 9 Jul 2021 18:27:47 +0200
Subject: implement basic kernel panics

---
 kernel/isr.c        |  3 ++-
 kernel/main.c       |  8 ++++----
 kernel/panic.h      | 14 ++++++++++++++
 kernel/proc.c       |  2 +-
 platform/asm.h      |  9 +++++++++
 platform/boot.s     |  5 ++++-
 platform/sysenter.h |  4 ----
 7 files changed, 34 insertions(+), 11 deletions(-)
 create mode 100644 kernel/panic.h
 create mode 100644 platform/asm.h
 delete mode 100644 platform/sysenter.h

diff --git a/kernel/isr.c b/kernel/isr.c
index 331e9a5..e6a9871 100644
--- a/kernel/isr.c
+++ b/kernel/isr.c
@@ -1,4 +1,5 @@
 #include <kernel/isr.h>
+#include <kernel/panic.h>
 #include <kernel/tty.h>
 #include <stdbool.h>
 #include <stdint.h>
@@ -8,7 +9,7 @@ bool isr_test_interrupt_called = false;
 __attribute__((interrupt))
 void isr_double_fault(struct interrupt_frame *frame) {
 	tty_const("#DF");
-	for(;;);
+	panic();
 }
 
 __attribute__((interrupt))
diff --git a/kernel/main.c b/kernel/main.c
index bc1e0d3..85a85d6 100644
--- a/kernel/main.c
+++ b/kernel/main.c
@@ -1,9 +1,10 @@
 #include <kernel/gdt.h>
 #include <kernel/idt.h>
 #include <kernel/mem.h>
+#include <kernel/panic.h>
 #include <kernel/proc.h>
 #include <kernel/tty.h>
-#include <platform/sysenter.h>
+#include <platform/asm.h>
 
 void r3_test();
 
@@ -23,7 +24,6 @@ void kmain()
 
 void r3_test() {
 	tty_const("ok");
-	asm("cli"); // privileged instruction, should cause a GP
-	tty_const(" this shouldn't happen");
-	for (;;) {}
+	asm("cli");
+	panic();
 }
diff --git a/kernel/panic.h b/kernel/panic.h
new file mode 100644
index 0000000..7d2ea5f
--- /dev/null
+++ b/kernel/panic.h
@@ -0,0 +1,14 @@
+#pragma once
+#include <kernel/tty.h>
+#include <platform/asm.h>
+
+// dumb c shit
+#define panic_tostr2(x) #x
+#define panic_tostr(x)  panic_tostr2(x)
+
+#define panic() do { \
+	tty_const(" PANIC! at the "); \
+	tty_const(__func__); \
+	tty_const(" (" __FILE__ ":" panic_tostr(__LINE__) ") "); \
+	halt_cpu(); \
+} while (0)
diff --git a/kernel/proc.c b/kernel/proc.c
index 959ef94..776238c 100644
--- a/kernel/proc.c
+++ b/kernel/proc.c
@@ -1,6 +1,6 @@
 #include <kernel/mem.h>
 #include <kernel/proc.h>
-#include <platform/sysenter.h>
+#include <platform/asm.h>
 
 struct process *process_current;
 
diff --git a/platform/asm.h b/platform/asm.h
new file mode 100644
index 0000000..6f72617
--- /dev/null
+++ b/platform/asm.h
@@ -0,0 +1,9 @@
+#pragma once
+
+// boot.s
+__attribute__((noreturn))
+void halt_cpu();
+
+// sysenter.c
+void sysexit(void (*fun)(), void *stack_top);
+void sysenter_setup();
diff --git a/platform/boot.s b/platform/boot.s
index 6052347..c2a06c3 100644
--- a/platform/boot.s
+++ b/platform/boot.s
@@ -27,7 +27,10 @@ _start:
 	mov $stack_top, %esp
 	call kmain
 
-	cli /* disable interrupts */
+.global halt_cpu
+.type halt_cpu, @function
+halt_cpu:
+	cli
 1:	hlt
 	jmp 1b
 
diff --git a/platform/sysenter.h b/platform/sysenter.h
deleted file mode 100644
index b0495cc..0000000
--- a/platform/sysenter.h
+++ /dev/null
@@ -1,4 +0,0 @@
-#pragma once
-
-void sysexit(void (*fun)(), void *stack_top);
-void sysenter_setup();
-- 
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