From 1d8a4028ca290cd0a99164038bd5a034cf052afa Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Sun, 16 Nov 2025 12:59:49 -0500
Subject: kern: panic: Deprecate mu_panic_preamble()

This commit deprecates mu_panic_preamble() in favor of the
mu_spinlock_acq() function

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 sys/arch/amd64/os/os_panic.c | 19 -------------------
 sys/inc/mu/panic.h           |  6 ------
 sys/kern/kern_panic.c        |  5 ++++-
 3 files changed, 4 insertions(+), 26 deletions(-)

diff --git a/sys/arch/amd64/os/os_panic.c b/sys/arch/amd64/os/os_panic.c
index cd55aac..d6aa95e 100644
--- a/sys/arch/amd64/os/os_panic.c
+++ b/sys/arch/amd64/os/os_panic.c
@@ -30,25 +30,6 @@
 #include <sys/types.h>
 #include <mu/panic.h>
 
-void
-mu_panic_preamble(void)
-{
-    static uint64_t sync = 0;
-
-    asm volatile(
-        "cli\n\t"
-        "mov $1, %%rax\n\t"
-        "1:\n\t"
-        "   pause\n\t"
-        "   xchg %0, %%rax\n\t"
-        "   or %%rax, %%rax\n\t"
-        "   jnz 1b\n"
-        :
-        : "m" (sync)
-        : "memory"
-    );
-}
-
 void
 mu_panic_hcf(void)
 {
diff --git a/sys/inc/mu/panic.h b/sys/inc/mu/panic.h
index b592fcc..257c469 100644
--- a/sys/inc/mu/panic.h
+++ b/sys/inc/mu/panic.h
@@ -32,12 +32,6 @@
 
 #include <sys/types.h>
 
-/*
- * Called as soon as a panic is invoked, prevents other
- * processors from continuing and disables interrupts
- */
-void mu_panic_preamble(void);
-
 /*
  * Used internally by the panic function and implemented
  * per architecture to bring the system to a halt.
diff --git a/sys/kern/kern_panic.c b/sys/kern/kern_panic.c
index d6beccb..1ac9c64 100644
--- a/sys/kern/kern_panic.c
+++ b/sys/kern/kern_panic.c
@@ -30,10 +30,13 @@
 #include <kern/panic.h>
 #include <kern/serial.h>
 #include <mu/panic.h>
+#include <mu/spinlock.h>
 #include <lib/string.h>
 #include <lib/stdarg.h>
 #include <lib/stdbool.h>
 
+static volatile size_t __sync = 0;
+
 void
 panic(const char *fmt, ...)
 {
@@ -41,7 +44,7 @@ panic(const char *fmt, ...)
     static char buf[256];
     static va_list ap;
 
-    mu_panic_preamble();
+    mu_spinlock_acq(&__sync, SPINLOCK_INTTOG);
     va_start(ap, fmt);
 
     vsnprintf(buf, sizeof(buf), fmt, ap);
-- 
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