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From: girish <firstname.lastname@example.org>
Date: Tue, 26 Sep 2006 11:22:26 +0900
To: Atsushi Nemoto <email@example.com>
Cc: "firstname.lastname@example.org" <email@example.com>
Conversation: [PATCH] cleanup hardcoding __pa/__va macros etc. (take-2)
Subject: Re: [PATCH] cleanup hardcoding __pa/__va macros etc. (take-2)
The idea is to differentiate the Kseg0/Kseg1 segments in the physical area.
Beyond these areas lies the mapped area (or the HIGHMEM). What complicates
this matter further is their overlapping nature. The __pa()/__va() treated
all addresses mapped into PAGE_OFFSET (8000_0000) area. The effort is to
correctly differentiate these areas.
I could not think of any better solution & the only simplification I came up
/* 8000_0000 & above */
#define ISMAPPEDPA(x) ((x) > KSEG0)
/* below 2000_0000 */
#define ISUNMAPPEDVA(x) ((x) < HIGHMEM_START)
#define ISMAPPEDPA(x) (1)
#define ISMAPPEDVA(x) (1)
#define ___pa(x) ((unsigned long) (x) - KSEGX((x)))
#define __pa(x) (ISUNMAPPEDPA(x) ? ___pa((x)) : (x))
#define ___va(x) ((void *)((unsigned long) (x) + KSEG0))
#define __va(x) (ISUNMAPPEDVA(x) ? ___va((x)) : (x))
On 9/26/06 12:43 AM, "Atsushi Nemoto" <firstname.lastname@example.org> wrote:
> On Mon, 25 Sep 2006 23:51:46 +0900, girish <email@example.com> wrote:
>> Here is the patch again, attached as a text file. I don't have idea how
>> these macros should be on a 64bit machine, so I just left them as it is.
>> Could you please verify these macros again?
> Well, I should ask first: Why do you change __pa() and __va() ?
> I can not see point of ISMAPPED() testing. And these macros are used
> quite often so they should be as fast as possible.
> Atsushi Nemoto
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