Re: [GIT PULL] siginfo fix for v4.16-rc5
From: Josh Juran
Date: Tue Apr 03 2018 - 11:25:07 EST
On Apr 3, 2018, at 10:27 AM, Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote:
> Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> writes:
>> On Mon, Apr 2, 2018 at 10:17 PM, Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote:
>>> A 2-byte alignment for 4 byte pointers. That is a new one to me.
>> Not just for pointers, also for int and long.
> The smallest I have seen previously has been 64bit integers having
> 32bit alignment. 32bit entities having only 16bit alignment on a 32bit
> arch was simply a surprise. Even when it works there tend to be good
> reasons not to do that by default.
The 68K architecture began as 16-bit with the 68000. Rather than tightening requirements, the 68020 not only maintained compatibility with 16-bit alignment, but also forgave byte-misaligned data accesses (albeit with a performance penalty). Jumping to an odd address is still an error, though.