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>
This commit is contained in:
Andi Kleen 2007-08-10 22:31:08 +02:00 committed by Linus Torvalds
parent d3f7eae182
commit 43fb2387d0

View file

@ -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 )