From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Keith Mannthey <kmannth@us.ibm.com>
Cc: lkml <linux-kernel@vger.kernel.org>, John Stultz <johnstul@us.ibm.com>
Subject: Re: [RFC][Patch] IBM Real-Time "SMI Free" mode driver
Date: Wed, 11 Feb 2009 10:05:57 +0000 [thread overview]
Message-ID: <20090211100557.634529ae@lxorguk.ukuu.org.uk> (raw)
In-Reply-To: <1234312633.15410.546.camel@keith-laptop>
> + /*get the address for the RTL table from the EBDA */
> + ebda_addr = *(unsigned short *)phys_to_virt(0x40E);
> + ebda_addr <<= 4;
> + ebda_size = 64*1024;
Second problem - you'll crash some systems with the assumptions here
> + for (i = 0 ; i < ebda_size/4; i++) {
> + unsigned int *tmp = (unsigned int *) data++;
> + if (*tmp == RTL_MAGIC_IDENT) {
> + table_addr = ebda_addr + i;
> + ret = rtl_setup_sysfs();
> + goto exit;
> + }
> + }
Some machines place the EBDA in the top pages of the low 640K. Your 64K
walk will continue into ISA MMIO space which isn't safe to blindly read.
Alan
next prev parent reply other threads:[~2009-02-11 10:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-11 0:37 Keith Mannthey
2009-02-11 10:02 ` Alan Cox
2009-02-11 10:05 ` Alan Cox [this message]
2009-02-11 12:18 ` Michal Schmidt
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