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| author | Andi Kleen <ak@suse.de> | 2007-08-10 22:31:08 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-08-11 15:58:14 -0700 |
| commit | 43fb2387d0774a36f450b50d538cee84cf83858e (patch) | |
| tree | 2a7c894bb93aac523cc2228b5249e659a7df3a9b /Documentation/i386 | |
| parent | d3f7eae182b04997be19343a23f7009170f4f7a5 (diff) | |
| download | linux-43fb2387d0774a36f450b50d538cee84cf83858e.tar.gz linux-43fb2387d0774a36f450b50d538cee84cf83858e.tar.bz2 linux-43fb2387d0774a36f450b50d538cee84cf83858e.zip | |
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>
Diffstat (limited to 'Documentation/i386')
| -rw-r--r-- | Documentation/i386/zero-page.txt | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/Documentation/i386/zero-page.txt b/Documentation/i386/zero-page.txt index 75b3680c41eb..6c0817c45683 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 ) |