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From: Rob Herring <robh@kernel.org>
To: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
	Frank Rowand <frowand.list@gmail.com>,
	Rob Herring <robh+dt@kernel.org>,
	Marek Szyprowski <m.szyprowski@samsung.com>
Subject: Re: [PATCH 1/3] of: Fix truncation of memory sizes on 32-bit platforms
Date: Wed, 16 Jun 2021 12:05:01 -0600	[thread overview]
Message-ID: <20210616180501.GA3629188@robh.at.kernel.org> (raw)
In-Reply-To: <4a1117e72d13d26126f57be034c20dac02f1e915.1623835273.git.geert+renesas@glider.be>

On Wed, 16 Jun 2021 11:27:44 +0200, Geert Uytterhoeven wrote:
> Variable "size" has type "phys_addr_t", which can be either 32-bit or
> 64-bit on 32-bit systems, while "unsigned long" is always 32-bit on
> 32-bit systems.  Hence the cast in
> 
>     (unsigned long)size / SZ_1M
> 
> may truncate a 64-bit size to 32-bit, as casts have a higher operator
> precedence than divisions.
> 
> Fix this by inverting the order of the cast and division, which should
> be safe for memory blocks smaller than 4 PiB.  Note that the division is
> actually a shift, as SZ_1M is a power-of-two constant, hence there is no
> need to use div_u64().
> 
> While at it, use "%lu" to format "unsigned long".
> 
> Fixes: e8d9d1f5485b52ec ("drivers: of: add initialization code for static reserved memory")
> Fixes: 3f0c8206644836e4 ("drivers: of: add initialization code for dynamic reserved memory")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---
>  drivers/of/fdt.c             | 8 ++++----
>  drivers/of/of_reserved_mem.c | 8 ++++----
>  2 files changed, 8 insertions(+), 8 deletions(-)
> 

Applied, thanks!

  parent reply	other threads:[~2021-06-16 18:05 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-16  9:27 [PATCH 0/3] of: Miscellaneous fixes and cleanups Geert Uytterhoeven
2021-06-16  9:27 ` [PATCH 1/3] of: Fix truncation of memory sizes on 32-bit platforms Geert Uytterhoeven
2021-06-16  9:36   ` Marek Szyprowski
2021-06-16 18:05   ` Rob Herring [this message]
2021-06-16  9:27 ` [PATCH 2/3] of: Remove superfluous casts when printing u64 values Geert Uytterhoeven
2021-06-16 19:50   ` Rob Herring
2021-06-16  9:27 ` [PATCH 3/3] of: kexec: Always use FDT_PROP_INITRD_START and FDT_PROP_INITRD_END Geert Uytterhoeven
2021-06-16 17:14   ` Rob Herring
2021-06-16 19:36     ` Geert Uytterhoeven
2021-06-16 19:49       ` Rob Herring

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