From: Andrew Morton <akpm@linux-foundation.org>
To: Matthias Kaehlcke <mka@chromium.org>
Cc: zijun_hu <zijun_hu@htc.com>,
linux-kernel@vger.kernel.org,
Doug Anderson <dianders@chromium.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Greg Hackmann <ghackmann@google.com>,
Yury Norov <ynorov@caviumnetworks.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>
Subject: Re: [PATCH v2] bitops: Avoid integer overflow in GENMASK(_ULL)
Date: Thu, 3 Aug 2017 14:45:55 -0700 [thread overview]
Message-ID: <20170803144555.facd691eef60a85bcc06b697@linux-foundation.org> (raw)
In-Reply-To: <20170803212020.24939-1-mka@chromium.org>
On Thu, 3 Aug 2017 14:20:20 -0700 Matthias Kaehlcke <mka@chromium.org> wrote:
> GENMASK(_ULL) performs a left-shift of ~0UL(L), which technically
> results in an integer overflow. clang raises a warning if the overflow
> occurs in a preprocessor expression.
That's just irritaing.
> Clear the low-order bits through
> a substraction instead of the left-shift to avoid the overflow.
There's no change in .text size for a few files I tested so guess we
can live with it.
prev parent reply other threads:[~2017-08-03 21:46 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-03 21:20 [PATCH v2] bitops: Avoid integer overflow in GENMASK(_ULL) Matthias Kaehlcke
2017-08-03 21:45 ` Andrew Morton [this message]
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