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    FromAndi Kleen <>
    SubjectRe: [PATCH 9/33] i386 boot: Add serial output support to the decompressor
    DateWed, 2 Aug 2006 07:21:44 +0200
    On Wednesday 02 August 2006 06:57, Eric W. Biederman wrote:
    > Andi Kleen <ak@suse.de> writes:
    > 
    > >> > Actually the best way to reuse would be to first do 64bit uncompressor
    > >> > and linker directly, but short of that #includes would be fine too.
    > >> 
    > >> > Would be better to just pull in lib/string.c
    > >> 
    > >> Maybe.  Size is fairly important 
    > >
    > > Why is size important here?
    > 
    > For the same reason that we compress the kernel. ;)
    > 
    > This is the one chunk of code that we don't compress so every extra
    > byte makes our executable bigger.  Now I think the code size is
    > actually in the 32k - 64k range so as long as it is a minor change
    > it doesn't really matter.
    
       text    data     bss     dec     hex filename
       1909     352      12    2273     8e1 arch/x86_64/kernel/early_printk.o
       2212       0       0    2212     8a4 lib/string.o
    
    It's minor.
    
    > 
    > The big pain with using lib/string.c and
    > arch/x86_64/kernel/early_printk.c is that it is significant change
    > in how the code of misc.c is constructed.  
    
    Not if you use #include
    
    > Which means some 
    > serious reevaluation of all kinds of things need to be considered.
    > Making it a lot of work :)
    > 
    > One of the practical dangers is that we make it more likely
    > we can kill the boot by messing up the shared code.
    
    If they're messed up the later boot will fail too. Doesn't make
    too much difference.
    
    > 
    > I'm not certain what to think when even including normal
    > kernel headers causes problems.  It certainly makes me leery
    > of including normal kernel code.  But it might simplify some
    > of the problems too.
    
    On x86-64 some trouble comes from it being 32bit code. 
    That is why I suggested making it 64bit first, which would
    avoid many of the problems.
    
    > Whichever way I go scrutinizing that possibility carefully is
    > a lot of work.
    
    64bit conversion would be some work, the rest isn't I think.
    
    Alternatively if you don't like it we can just drop these compressor patches.
    I don't think they were essential.
    
    -Andi
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