linux-kernel - Re: [patch v2] x86: allow ZONE

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: <4DA82F33.7080403@ladisch.de>
Date:	Fri, 15 Apr 2011 13:42:43 +0200
From:	Clemens Ladisch <clemens@...isch.de>
To:	David Rientjes <rientjes@...gle.com>
CC:	Ingo Molnar <mingo@...hat.com>, "H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>, x86@...nel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [patch v2] x86: allow ZONE_DMA to be configurable

David Rientjes wrote:
> ZONE_DMA is unnecessary for a large number of machines that do not
> require addressing in the lower 16MB of memory because they do not use
> ISA devices with 16-bit address registers (plus one page byte register).
> 
> This patch allows users to disable ZONE_DMA for x86 if they know they
> will not be using such devices with their kernel.
> ...
>  config ZONE_DMA
> -	def_bool y
> +	bool "DMA memory allocation support" if EXPERT

Better call it "ISA/LPC DMA memory allocation support".

> +	default y

Does it make sense to have this without CONFIG_ISA_DMA_API?

> +	help
> +	  DMA memory allocation support allows old ISA devices with 16-bit
> +	  address registers to allocate memory within the first 16MB of
> +	  address space.  Disable if no such devices will be used.

"Old ISA devices" might be misleading because ISA does not imply actual
ISA slots; please mention LPC devices like the floppy controller and the
parallel port in ECP mode.


Regards,
Clemens
--
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/