linux-kernel - Re: [PATCH] [7/8] Implement true end_pfn

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Message-ID: <alpine.LFD.1.00.0802122035270.12988@apollo.tec.linutronix.de>
Date:	Tue, 12 Feb 2008 20:39:48 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Andi Kleen <ak@...e.de>
cc:	ying.huang@...el.com, mingo@...e.hu, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] [7/8] Implement true end_pfn_mapped for 32bit

On Mon, 11 Feb 2008, Andi Kleen wrote:
> Even on 32bit 2MB pages can map more memory than is in the true
> max_low_pfn if end_pfn is not highmem and not aligned to 2MB. 
> Add a end_pfn_map similar to x86-64 that accounts for this 
> fact. This is important for code that really needs to know about
> all mapping aliases. Needed for followup patches (in this case EFI)

It's not only necessary for followup patches, it is a question of
general correctness.

> @@ -36,7 +36,7 @@
>  #define max_pfn_mapped		end_pfn_map
>  #else
>  #include <asm/page_32.h>
> -#define max_pfn_mapped		max_low_pfn
> +#define max_pfn_mapped		end_pfn_map

We can nuke either max_pfn_mapped or end_pfn_map completely. I don't
care about which one, but keeping both makes no sense at all.

Thanks,

	tglx
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