Re: mainthread.cxx - unaligned stack possible

[Larice Robert <larice at vidisys dot de>]

> On Sun, 2003-03-09 at 10:42, Larice Robert wrote:
> > > Scott Furman wrote:
> > > > 
> > > > 
> > > > eCos provides the stack for main() when building with libc startup 
> > > > support and CYGSEM_LIBC_MAIN_STACK_FROM_SYSTEM is defined.  However, the 
> > > > stack is declared as an array of  cyg_uint8, so there is the possibility 
> > > > that it is unaligned.
> > > 
> > > Hmm.. I thought the linker was meant to do this for statics/globals. Oh 
> > > well, let's err on the side of caution...
> > > 
> > >  > The attached trivial fix ensures that the stack
> > > > is at least octlet-aligned.  (Does any architecture require an alignment 
> > > > stricter than 8 bytes ?)
> > > 
> > > Some can. I've checked in a slightly better version (attached).
> > > 
> > > Jifl
> > 
> > Hello Jonathan Larmour,
> > 
> >   obviously the linker does not what you thought.
> >   i've a small test case here:
> > 
> > 
> 
> But, you didn't add the "alignment magic" that Jonathan did.
> Try it like this:
> 
> #define CYGBLD_ATTRIB_ALIGN(__align__) __attribute__((aligned(__align__)))
> ...

Hello Gary Thomas,

  please excuse my misarable english, i think you've got my letter
  wrong. my sentence:
   > >   obviously the linker does not what you thought.
  was meant in the following way:
   Jonathan had the impression the linker will automatically add sufficient
   alignment to a global char array.  And I reply, this is not the case.

  of course adding the __attribute__(aligned...)) is perfectly ok to 
  solve the issue.

  But once you have understood, that such an attribute is necessairy,
  then there is a important consequence:

    Don't fix just one or the other such global char array, 
    but fix ALL of them in the ecos source code.

  as i've allready said, in
   (http://sources.redhat.com/ml/ecos-patches/2002-06/msg00021.html)
  is a fix for apporoximately 200 such occurences in ecos.

Thank you,
   Robert Larice