Re: [kernel-hardening] Re: [PATCH v2 1/4] siphash: add cryptographically secure hashtable function

On Thu, Dec 15, 2016 at 10:09 PM, Peter Zijlstra [off-list ref] wrote:

On Thu, Dec 15, 2016 at 07:50:36PM +0100, Jason A. Donenfeld wrote:

quoted

There's no 32-bit platform
that will trap on a 64-bit unaligned access because there's no such
thing as a 64-bit access there. In short, we're fine.

ARMv7 LPAE is a 32bit architecture that has 64bit load/stores IIRC.

x86 has cmpxchg8b that can do 64bit things and very much wants the u64
aligned.

Also, IIRC we have a few platforms where u64 doesn't carry 8 byte
alignment, m68k or something like that, but yes, you likely don't care.

Indeed, I stand corrected. But in any case, the use of __aligned(8) in
the patchset ensures that things are fixed and that we don't have this
issue.