From 43fb2387d0774a36f450b50d538cee84cf83858e Mon Sep 17 00:00:00 2001
From: Andi Kleen <ak@suse.de>
Date: Fri, 10 Aug 2007 22:31:08 +0200
Subject: [PATCH] i386: Add warning in Documentation that zero-page is not a
stable ABI
Some people writing boot loaders seem to falsely belief the 32bit zero page is a
stable interface for out of tree code like the real mode boot protocol. Add a comment
clarifying that is not true.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
Documentation/i386/zero-page.txt | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/Documentation/i386/zero-page.txt b/Documentation/i386/zero-page.txt
index 75b3680c41eb8..6c0817c45683f 100644
--- a/Documentation/i386/zero-page.txt
+++ b/Documentation/i386/zero-page.txt
@@ -1,3 +1,13 @@
+---------------------------------------------------------------------------
+!!!!!!!!!!!!!!!WARNING!!!!!!!!
+The zero page is a kernel internal data structure, not a stable ABI. It might change
+without warning and the kernel has no way to detect old version of it.
+If you're writing some external code like a boot loader you should only use
+the stable versioned real mode boot protocol described in boot.txt. Otherwise the kernel
+might break you at any time.
+!!!!!!!!!!!!!WARNING!!!!!!!!!!!
+----------------------------------------------------------------------------
+
Summary of boot_params layout (kernel point of view)
( collected by Hans Lermen and Martin Mares )
--
GitLab