--Tom
-----Original Message-----
From: Ralf Baechle <ralf@uni-koblenz.de>
To: Jamie Lokier <lkd@tantalophile.demon.co.uk>
Cc: linux-kernel@vger.rutgers.edu <linux-kernel@vger.rutgers.edu>
Date: Tuesday, June 01, 1999 11:53 AM
Subject: Re: ptrace question ...
>On Tue, Jun 01, 1999 at 04:01:25PM +0200, Jamie Lokier wrote:
>
>> Ralf Baechle wrote:
>> > Is there any reason why we don't attempt to handle requests for
addresses
>> > with MAP_NR(page) >= MAP_NR(high_memory) correctly? I've got a pending
>> > bug report for the MIPS port where somebody complains that the
respective
>> > code for MIPS prevents accessing the hardware directly from GDB.
>>
>> Yes: if you remove the test, accessing the hardware still doesn't work!
>
>Obviously. However that code was written even before Linux 1.0 and
>at that time there was no ioremap that is all memory mappaple devices
>were permanently accessible.
>
>> > *(unsigned long *) (page + (addr & ~PAGE_MASK)) = data;
>>
>> This line only works for pages where MAP_NR(page) < MAP_NR(high_memory).
>> To access other hardware addresses from kernel space requires a call
>> to ioremap() first.
>>
>> Well ok, _some_ addresses will still work if the phase of your moon is
>> right, but not reliably.
>
>Will make it work right ...
>
>> However I don't know why the test isn't simply `page < high_memory'.
>
>In Linux 1.0 it basically was.
>
> Ralf
>
>-
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