From: Benjamin Berg <benjamin.berg@intel.com>
Date: Thu, 19 Sep 2024 12:45:06 +0000 (+0200)
Subject: um: Add compile time assert that stub fits on a page
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=77eb31b6003a158cce534fa9ca9df21fc82672ea;p=users%2Fjedix%2Flinux-maple.git

um: Add compile time assert that stub fits on a page

The code assumes that the stub code can fit into a single page. This is
unlikely to ever change, but add a link time assert instead so that
there will be no hard to debug error.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20240919124511.282088-6-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---

diff --git a/arch/um/kernel/dyn.lds.S b/arch/um/kernel/dyn.lds.S
index 3385d653ebd0d..dc9d9a68af559 100644
--- a/arch/um/kernel/dyn.lds.S
+++ b/arch/um/kernel/dyn.lds.S
@@ -178,3 +178,6 @@ SECTIONS
 
   DISCARDS
 }
+
+ASSERT(__syscall_stub_end - __syscall_stub_start <= PAGE_SIZE,
+       "STUB code must not be larger than one page");