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From:   David Laight <David.Laight@ACULAB.COM>
To:     'Andrew Morton' <akpm@linux-foundation.org>,
        Joe Perches <joe@perches.com>,
        Andy Whitcroft <apw@canonical.com>,
        LKML <linux-kernel@vger.kernel.org>
Subject: RE: [RFC PATCH] checkpatch: check for function calls with struct or
 union on stack
Thread-Topic: [RFC PATCH] checkpatch: check for function calls with struct or
 union on stack
Thread-Index: AQHUJRcFUx4+BuOgSky66zuZVVqB+6Si1nhw
Date:   Fri, 27 Jul 2018 10:04:54 +0000
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        <20180726122533.104f6eea950853ef50ebc680@linux-foundation.org>
 <20180726122807.fad0566951e36d930edb6874@linux-foundation.org>
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From: Andrew Morton
> Sent: 26 July 2018 20:28
> On Thu, 26 Jul 2018 12:25:33 -0700 Andrew Morton <akpm@linux-foundation.org> wrote:
> 
> > I'll give it a spin, see how noisy it is.
> 
> Actually, I would prefer if the message, changelog and title
> used the term "passed by value".  It's a more familiar term
> and it is possible for a passed-by-value aggregate to in fact
> be passed in registers.

You need to detect (and ignore) 'small' structures.
Quite a few ABI pass small structures by value in register(s)
or directly on the stack.

So it can make sense to encapsulate an integer value in a
structure in order to get strong typing.

It would, for instance, make sense to do that for user addresses.

	David

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