From b559b8dbf70a2c1b35ac09a19ef6d2064d3942f5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lo=C3=AFc=20Gr=C3=A9goire?= <loic@gregoire.dev>
Date: Fri, 3 Jul 2026 10:27:41 -0400
Subject: [PATCH] pl(pc): fix overflow in deadline calculation

---
 src/platform/pc/apic.zig | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/platform/pc/apic.zig b/src/platform/pc/apic.zig
index 26a01eb..0ba1832 100644
--- a/src/platform/pc/apic.zig
+++ b/src/platform/pc/apic.zig
@@ -199,7 +199,11 @@ fn timer_init() linksection(r.init) void {
 pub fn arm_timer(ns: r.Nanoseconds) void {
     if (amd64.cpu_features.tsc_deadline) {
         const now = amd64.rdtsc();
-        const deadline = now + (ns * tsc.tsc_timer.frequency / std.time.ns_per_s);
+
+        const delta: u64 = @intCast((@as(u128, ns) * tsc.tsc_timer.frequency) / std.time.ns_per_s);
+
+        const deadline = now +% delta;
+
         amd64.write_msr(.TscDeadline, deadline);
         return;
     }