Re: [PATCH] Introduce compat_u64 and compat_s64 types

From: Andi Kleen
Date: Fri Jun 15 2007 - 07:56:51 EST


On Friday 15 June 2007 11:31:37 Arnd Bergmann wrote:
> One common problem with 32 bit system call and ioctl emulation
> is the different alignment rules between i386 and 64 bit machines.
> A number of drivers work around this by marking the compat
> structures as 'attribute((packed))', which is not the right
> solution because it breaks all the non-x86 architectures that
> want to use the same compat code.

Why does it break them? It should just make them a little slower.

The network code requires unaligned accesses to work
anyways so if your architecture doesn't support them it is already
remotely crashable.

-Andi

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/