linux-kernel - Re: [tip:x86/urgent] x86, efi: Delete efi_ioremap() and fix CONFIG_X86

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Date:	Thu, 23 Feb 2012 02:36:10 -0800
From:	Yinghai Lu <yinghai@...nel.org>
To:	"H. Peter Anvin" <hpa@...or.com>, matt.fleming@...el.com,
	mingo@...hat.com
Cc:	mjg@...hat.com, linux-kernel@...r.kernel.org, keithp@...thp.com,
	rui.zhang@...el.com, huang.ying.caritas@...il.com,
	stable@...r.kernel.org, tglx@...utronix.de,
	linux-tip-commits@...r.kernel.org
Subject: Re: [tip:x86/urgent] x86, efi: Delete efi_ioremap() and fix
 CONFIG_X86_32 oops

On Wed, Feb 22, 2012 at 7:32 PM, H. Peter Anvin <hpa@...or.com> wrote:
> On 02/22/2012 06:20 PM, Yinghai Lu wrote:
>>
>> Why is MAXMEM used here?
>>
>> EFI reserved area could be above 4G?
>>
>> if that is the case, you will map all mmio hole below 4g.
>>
>
> OK, dropping this patch for now, at least from -urgent.
>
> We really need to restrict the memory types we map, at least without
> ioremap() called on them.  In theory, on x86-64, we could have a
> dedicated "1:1" address for each physical address, but there is no good
> reason we should ever map memory types other than RAM, ACPI and EFI by
> default -- with the possible exception of the low 1 MiB legacy area.

please check attach patch for tip/efi branch.

Thanks

       Yinghai

View attachment "fix_efi_map_end.patch" of type "text/x-patch" (2322 bytes)