From: Jeremy Fitzhardinge <jeremy@goop.org>
To: benh@kernel.crashing.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
ehabkost@redhat.com, x86@kernel.org,
linux-kernel@vger.kernel.org, Paul Mackerras <paulus@samba.org>
Subject: Re: [PATCH 1/2] add phys_addr_t for holding physical addresses
Date: Mon, 11 Aug 2008 15:15:07 -0700 [thread overview]
Message-ID: <48A0B9EB.9020709@goop.org> (raw)
In-Reply-To: <1218491896.8041.9.camel@pasglop>
Benjamin Herrenschmidt wrote:
> On Mon, 2008-08-11 at 12:38 -0700, Jeremy Fitzhardinge wrote:
>
>> Add a kernel-wide "phys_addr_t" which is guaranteed to be able to hold
>> any physical address. By default it equals the word size of the
>> architecture, but a 32-bit architecture can set ARCH_PHYS_ADDR_T_64BIT
>> if it needs a 64-bit phys_addr_t.
>>
>
> I've been wondering for some time why can't we make phys_addr_t and
> resource_size_t the same thing... I don't like having two ARCH_* thing
> especially since I believe the one for resources is already what we
> want.
>
I made the same argument, but Andrew thinks they're conceptually
distinct. It is theoretically possible you might have a system with >4G
memory, but all io resources < 4G, so you'd have resource_size_t
32-bits, while having 64-bit physical addresses. You can configure such
a thing, but I don't know if it's 1) useful or 2) used.
J
next prev parent reply other threads:[~2008-08-11 22:15 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <489B6B40.5050705@goop.org>
[not found] ` <20080807145648.ab3dfa90.akpm@linux-foundation.org>
2008-08-07 22:10 ` [PATCH] Make PFN_PHYS return a properly-formed physical address Jeremy Fitzhardinge
2008-08-07 23:27 ` Andrew Morton
2008-08-07 23:45 ` Jeremy Fitzhardinge
2008-08-08 0:06 ` Andrew Morton
2008-08-08 0:16 ` Jeremy Fitzhardinge
2008-08-11 19:38 ` [PATCH 1/2] add phys_addr_t for holding physical addresses Jeremy Fitzhardinge
2008-08-11 21:58 ` Benjamin Herrenschmidt
2008-08-11 22:15 ` Jeremy Fitzhardinge [this message]
2008-08-11 22:32 ` Benjamin Herrenschmidt
2008-08-11 22:50 ` Jeremy Fitzhardinge
2008-08-11 22:53 ` Benjamin Herrenschmidt
2008-08-11 23:02 ` Jeremy Fitzhardinge
2008-08-11 23:17 ` Benjamin Herrenschmidt
2008-08-11 19:38 ` [PATCH 2/2] make PFN_PHYS explicitly return phys_addr_t Jeremy Fitzhardinge
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