Re: kexec, x86/purgatory: Cleanup the unholy mess

From: Mike Galbraith
Date: Fri Mar 10 2017 - 08:48:31 EST

On Fri, 2017-03-10 at 13:17 +0100, Thomas Gleixner wrote:
> The purgatory code defines global variables which are referenced via a
> symbol lookup in the kexec code (core and arch).
> A recent commit addressing sparse warning made these static and thereby
> broke kexec file.
> Why did this happen? Simply because the whole machinery is undocumented and
> lacks any form of forward declarations. The variable names are unspecific
> and lack a prefix, so adding forward declarations creates shadow variables
> in the core code. Aside of that the code relies on magic constants and
> duplicate struct definitions with no way to ensure that these things stay
> in sync.
> Unbreak kexec and cleanup the mess by:
> - Adding proper forward declarations and document the usage
> - Use the proper common defines instead of magic constants
> - Add a purgatory_ prefix to have a proper name space
> - Use ARRAY_SIZE() instead of a homebrewn reimplementation
> Fixes: 72042a8c7b01 ("x86/purgatory: Make functions and variables static")

Well, almost fixes.

[ 15.118820] kexec: symbol 'purgatory_sha_regions' in common section
[ 15.119187] kexec-bzImage64: Loading purgatory failed