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From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: David Laight <David.Laight@aculab.com>
Cc: Colin King <colin.king@canonical.com>,
	 Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>,
	Srinivas Neeli <srinivas.neeli@xilinx.com>,
	 Michal Simek <michal.simek@xilinx.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	 Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	 Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	 "linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>,
	 "linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	 "kernel-janitors@vger.kernel.org"
	<kernel-janitors@vger.kernel.org>,
	 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH][next] gpio: xilinx: Fix potential integer overflow on shift of a u32 int
Date: Mon, 17 May 2021 10:04:59 +0300	[thread overview]
Message-ID: <CAHp75VdJ9n6Sm2HQYE_bfg-5vXceA3aG5aXOfCctxDjzhLVXpA@mail.gmail.com> (raw)
In-Reply-To: <ca5918c4d9a240bc80bad1ad16d929f9@AcuMS.aculab.com>

On Thu, May 13, 2021 at 1:04 PM David Laight <David.Laight@aculab.com> wrote:
> > From: Colin Ian King <colin.king@canonical.com>

> > @@ -99,7 +99,7 @@ static inline void xgpio_set_value32(unsigned long *map, int bit, u32 v)
> >       const unsigned long offset = (bit % BITS_PER_LONG) & BIT(5);
> >
> >       map[index] &= ~(0xFFFFFFFFul << offset);
> > -     map[index] |= v << offset;
> > +     map[index] |= (unsigned long)v << offset;
> >  }
>
> That code looks dubious on 32bit architectures.
>
> I don't have 02b3f84d9080 in any of my source trees.

Can you please be more specific on which code is dubious on 32-bit
arches and why?

> But that patch may itself be very dubious.
>
> Since the hardware requires explicit bits be set, relying
> on the bitmap functions seems pointless and possibly wrong.
> Clearly they cause additional problems because they use long[]
> and here the code needs u32[].

-- 
With Best Regards,
Andy Shevchenko

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  reply	other threads:[~2021-05-17  7:09 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-13  8:52 [PATCH][next] gpio: xilinx: Fix potential integer overflow on shift of a u32 int Colin King
2021-05-13  9:10 ` David Laight
2021-05-17  7:04   ` Andy Shevchenko [this message]
2021-05-14  5:37 ` Dan Carpenter
2021-05-17  7:07   ` Andy Shevchenko
2021-05-17 13:36     ` Dan Carpenter
2021-05-17 13:49       ` Andy Shevchenko
2021-05-17  7:03 ` Andy Shevchenko
2021-05-17  7:32   ` Andy Shevchenko

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