From: Stepan Moskovchenko <stepanm@codeaurora.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arm-kernel@lists.infradead.org,
Russell King <linux@arm.linux.org.uk>,
linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
David Brown <davidb@codeaurora.org>,
Bryan Huntsman <bryanh@codeaurora.org>,
Daniel Walker <dwalker@fifo99.com>
Subject: Re: [PATCH] arm: Prevent memory aliasing on non-LPAE kernels
Date: Fri, 31 May 2013 18:30:52 -0700 [thread overview]
Message-ID: <51A94ECC.5090303@codeaurora.org> (raw)
In-Reply-To: <3054064.aJsgTxiNUL@wuerfel>
On 5/30/2013 3:24 PM, Arnd Bergmann wrote:
>> + if (size > ((phys_addr_t)~0))
>> + size = ((phys_addr_t)~0);
>> +
>> + /* arm_add_memory() already checks for the case of base + size > 4GB */
>> +#endif
>> arm_add_memory(base, size);
>> }
>
> This looks wrong for the case where 'base' is between >0 and 4GB and 'size'
> makes it spill over the 4GB boundary. You need to set
> 'size = (phys_addr_t)~0 - base' then.
>
Ah. I believe arm_add_memory() already has the logic to handle this
case. Here, we are just trying to shrink 'size' to fit into phys_addr_t,
since it is currently u64 but arm_add_memory() uses phys_addr_t for its
arguments. I did not want to have this logic in two places, but I can do
what you said if you like.
--
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation
WARNING: multiple messages have this Message-ID (diff)
From: stepanm@codeaurora.org (Stepan Moskovchenko)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm: Prevent memory aliasing on non-LPAE kernels
Date: Fri, 31 May 2013 18:30:52 -0700 [thread overview]
Message-ID: <51A94ECC.5090303@codeaurora.org> (raw)
In-Reply-To: <3054064.aJsgTxiNUL@wuerfel>
On 5/30/2013 3:24 PM, Arnd Bergmann wrote:
>> + if (size > ((phys_addr_t)~0))
>> + size = ((phys_addr_t)~0);
>> +
>> + /* arm_add_memory() already checks for the case of base + size > 4GB */
>> +#endif
>> arm_add_memory(base, size);
>> }
>
> This looks wrong for the case where 'base' is between >0 and 4GB and 'size'
> makes it spill over the 4GB boundary. You need to set
> 'size = (phys_addr_t)~0 - base' then.
>
Ah. I believe arm_add_memory() already has the logic to handle this
case. Here, we are just trying to shrink 'size' to fit into phys_addr_t,
since it is currently u64 but arm_add_memory() uses phys_addr_t for its
arguments. I did not want to have this logic in two places, but I can do
what you said if you like.
--
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation
next prev parent reply other threads:[~2013-06-01 1:30 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-30 21:45 [PATCH] arm: Prevent memory aliasing on non-LPAE kernels Stepan Moskovchenko
2013-05-30 21:45 ` Stepan Moskovchenko
2013-05-30 21:45 ` Stepan Moskovchenko
2013-05-30 22:10 ` Jason Gunthorpe
2013-05-30 22:10 ` Jason Gunthorpe
2013-05-30 22:24 ` Arnd Bergmann
2013-05-30 22:24 ` Arnd Bergmann
2013-06-01 1:30 ` Stepan Moskovchenko [this message]
2013-06-01 1:30 ` Stepan Moskovchenko
2013-06-10 5:24 ` Magnus Damm
2013-06-10 5:24 ` Magnus Damm
2013-08-29 7:08 ` takashi.yoshii.zj
2013-08-29 7:08 ` takashi.yoshii.zj at renesas.com
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