From 7842d35829e0e07b73f426c4c9e29eba1018a75a Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Tue, 23 Dec 2025 15:17:11 -0500
Subject: mos: kern: Add panic function

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 mos/sys/inc/kern/panic.h  | 18 ++++++++++++++++++
 mos/sys/kern/kern_panic.c | 29 +++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+)
 create mode 100644 mos/sys/inc/kern/panic.h
 create mode 100644 mos/sys/kern/kern_panic.c

diff --git a/mos/sys/inc/kern/panic.h b/mos/sys/inc/kern/panic.h
new file mode 100644
index 0000000..a7aac0e
--- /dev/null
+++ b/mos/sys/inc/kern/panic.h
@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2025, Ian Moffett.
+ * Provided under the BSD-3 clause.
+ */
+
+#ifndef _KERN_PANIC_H_
+#define _KERN_PANIC_H_ 1
+
+#include <sdk/types.h>
+#include <sdk/stdarg.h>
+
+/*
+ * Signal to the operator that a severe error has
+ * occurred and the system has been halted.
+ */
+void panic(const char *fmt, ...);
+
+#endif  /* !_KERN_PANIC_H_ */
diff --git a/mos/sys/kern/kern_panic.c b/mos/sys/kern/kern_panic.c
new file mode 100644
index 0000000..8f03e6a
--- /dev/null
+++ b/mos/sys/kern/kern_panic.c
@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2025, Ian Moffett.
+ * Provided under the BSD-3 clause.
+ */
+
+#include <sdk/string.h>
+#include <kern/panic.h>
+#include <kern/spinlock.h>
+#include <kern/trace.h>
+#include <mu/cpu.h>
+
+static SPINLOCK panic_sync;
+static char panic_buf[256];
+static va_list ap;
+
+void
+panic(const char *fmt, ...)
+{
+    spinlock_acquire(&panic_sync, SPINLOCK_IRQMUT);
+    va_start(ap, fmt);
+
+    vsnprintf(panic_buf, sizeof(panic_buf), fmt, ap);
+    trace("panic: ");
+    trace(panic_buf);
+
+    for (;;) {
+        mu_cpu_halt();
+    }
+}
-- 
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