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    kexec, x86/purgatory: Unbreak it and clean it up · 40c50c1f
    Thomas Gleixner authored
    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 warnings 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. The section placement of the purgatory variables happened by
    chance and not by design.
    
    Unbreak kexec and cleanup the mess:
    
     - Add proper forward declarations and document the usage
     - Use common struct definition
     - 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
     - Add proper sections to the purgatory variables [ From Mike ]
    
    Fixes: 72042a8c
    
     ("x86/purgatory: Make functions and variables static")
    Reported-by: default avatarMike Galbraith <&lt;efault@gmx.de>
    Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    Cc: Nicholas Mc Guire <der.herr@hofr.at>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Vivek Goyal <vgoyal@redhat.com>
    Cc: "Tobin C. Harding" <me@tobin.cc>
    Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1703101315140.3681@nanos
    
    
    Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    40c50c1f