Subject: Re: structure alignment on arm in NetBSD? (resend without html)
To: None <>
From: Christos Zoulas <>
List: tech-toolchain
Date: 10/15/2007 18:11:09
In article <>,
Martin Fouts <> wrote:
>Deep in the heart of gcc sources, 
>In src/gnu/dist/gcc4/gcc/config/arm/netbsd-elf.h I found the comment
>/* VERY BIG NOTE: Change of structure alignment for NetBSD/arm.
>   There are consequences you should be aware of...
>   Normally GCC/arm uses a structure alignment of 32 for compatibility
>   with armcc.  This means that structures are padded to a word
>   boundary.  However this causes problems with bugged NetBSD kernel
>   code (possibly userland code as well - I have not checked every
>   binary).  The nature of this bugged code is to rely on sizeof()
>   returning the correct size of various structures rounded to the
>   nearest byte (SCSI and ether code are two examples, the vm system
>   is another).  This code breaks when the structure alignment is 32
>   as sizeof() will report a word=3Drounded size.  By changing the
>   structure alignment to 8. GCC will conform to what is expected by
>   NetBSD.
>(rest elided...)
>Is this comment still accurate?

I am not sure, but the kernel structures should be fixed instead...