From: Ronald G Minnich <rminnich@lanl.gov>
To: <9fans@cse.psu.edu>
Subject: Re: [9fans] Question on mapping 0xfff00000
Date: Fri, 23 Mar 2001 18:43:55 -0700 [thread overview]
Message-ID: <Pine.LNX.4.30.0103231841400.20312-100000@white.acl.lanl.gov> (raw)
In-Reply-To: <20010321013034.07203199FB@mail.cse.psu.edu>
On Tue, 20 Mar 2001 jmk@plan9.bell-labs.com wrote:
> Looks like an arithmetic overflow problem. The clue is that the return
> should be the ending address of the successfully mapped area. But if you
> add 0xfff00000+0x100000 you get 0x100000000, which is 0 in 32-bits and the
> mapping loop in mmu.c:^mmukmap() is
ok, yes, it is an arithmetic overflow. My fix is to not try to map that
last page, as i will not really need it anyway for what I am doing.
Also, it turns out the return for upamalloc is 0 for fail, and the
STARTING address on success. Just FYI.
thanks for the help, that cleared up the problems I was having. I should
have caught that as many times as I've been bitten by the "last page bug"
in various OSes. My driver is now happy.
ron
next prev parent reply other threads:[~2001-03-24 1:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-03-21 1:30 jmk
2001-03-24 1:43 ` Ronald G Minnich [this message]
-- strict thread matches above, loose matches on Subject: below --
2001-03-20 6:06 Ronald G Minnich
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