linux-kernel - Re: [PATCH v3 2/3] arm64: dts: Add APM X-Gene DMA device and DMA clock DTS nodes

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <2407238.x2YxDm0cd4@wuerfel>
Date:	Mon, 19 Jan 2015 14:40:36 +0100
From:	Arnd Bergmann <arnd@...db.de>
To:	Rameshwar Prasad Sahu <rsahu@....com>
Cc:	vinod.koul@...el.com, dan.j.williams@...el.com,
	dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org,
	devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	ddutile@...hat.com, jcm@...hat.com, patches@....com,
	Loc Ho <lho@....com>
Subject: Re: [PATCH v3 2/3] arm64: dts: Add APM X-Gene DMA device and DMA clock DTS nodes

On Monday 19 January 2015 18:11:08 Rameshwar Prasad Sahu wrote:
> diff --git a/arch/arm64/boot/dts/apm/apm-storm.dtsi b/arch/arm64/boot/dts/apm/apm-storm.dtsi
> index f1ad9c2..e20da23 100644
> --- a/arch/arm64/boot/dts/apm/apm-storm.dtsi
> +++ b/arch/arm64/boot/dts/apm/apm-storm.dtsi
> @@ -103,6 +103,9 @@
>                 #size-cells = <2>;
>                 ranges;
> 
> +               /* DDR range is 42-bit addressing */
> +               dma-ranges = <0x40 0x0 0x40 0x0 0x1ff 0xffffffff>;
> +
> 

The comment above is misleading, and the value is wrong. I assume you
copied these from the AMD patch that introduced the respective property.

The value should be

	dma-ranges = <0x40 0x0 0x40 0x0 0x200 0>;

to say that any DMA to physical addresses from 0 to 0x3f.ffffffff
is disallowed and dma to physical addresses from 0x40.00000000
to 0x23f.ffffffff is allowed and gets translated using an
identity mapping.

I also see that on Mustang, all memory is outside of this range,
which is a bit suspicious, while your PCI memory space is
included.

It would be best to match the numbers up with your data sheet.

	Arnd
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/