• Vivek Goyal's avatar
    [PATCH] Re-positioning the bss segment · 120b1142
    Vivek Goyal authored
    [AK: This apparently broke some systems, but we need it to fix
    a compile problem with old binutils and in theory the patch
    is correct. So let's trying reenabling it again.]
    
    o Currently bss segment is being placed somewhere in the middle (after .data)
      section and after bss lots of init section and data sections are coming.
      Is it intentional?
    
    o One side affect of placing bss in the middle is that objcopy keeps the
      bss in raw binary image (vmlinux.bin) hence unnecessarily increasing
      the size of raw binary image. (In my case ~600K). It also increases
      the size of generated bzImage, though the increase is very small
      (896 bytes), probably a very high compression ratio for stream
      of zeros.
    
    o This patch moves the bss at the end hence reducing the size of
      bzImage by 896 bytes and size of vmlinux.bin by 600K.
    
    o This change benefits in the context of relocatable kernel patches. If
      kernel bss is not part of compressed data (vmlinux.bin) then it does
      not have to be decompressed and this area can be used by the decompressor
      for its execution hence keeping the memory requirements bounded and
      decompressor code does not stomp over any other data loaded beyond
      kernel image (As might be the case with bootloaders like kexec).
    Signed-off-by: default avatarVivek Goyal <vgoyal@in.ibm.com>
    Signed-off-by: default avatarAndi Kleen <ak@suse.de>
    120b1142
vmlinux.lds.S 6.51 KB