Re: [linuxsh-dev] bad alignment fixup

[Philipp R. <pr...@pa...>]

On Wed, Nov 08, 2000 at 03:17:35AM +1100, Mitch Davis wrote:
> Many moons ago I used a Unix that supported unaligned accesses so that
> binaries from a previous version of the operating system would run.
> While the programs ran successfully, the alignment faults caused
> less than stellar performance.  However if all you've got is binaries,
> I guess it's the only choice.

We don't support unaligned userspace accesses for userspace.  All we're
doing is to catch unaligned accesses caused by the network code when it
deals with network protocols that make ip headers (for example) unaligned.

> With the general prevalence of source code for Linux programs, and
> no existing body of LinuxSH programs with unaligned access problems,
> I would suggest that a good reason not to include the patch would be
> so that we don't ever have buggy programs running silently but slowly.

Removing the "!user_mode(regs)" check would indeed cause the problems you
described.  The other architectures don't do that, either.

	Philipp Rumpf