Re: [tip:x86/urgent] x86: Make 64-bit efi_ioremap use ioremap on MMIO regions

[Huang Ying <ying.huang@intel.com>]

On Tue, 2009-08-04 at 01:12 +0800, tip-bot for Paul Mackerras wrote:
> Commit-ID:  19157af82cf0575032386f60378527904dbb7b8f
> Gitweb:     http://git.kernel.org/tip/19157af82cf0575032386f60378527904dbb7b8f
> Author:     Paul Mackerras <paulus@samba.org>
> AuthorDate: Mon, 3 Aug 2009 22:38:10 +1000
> Committer:  H. Peter Anvin <hpa@zytor.com>
> CommitDate: Mon, 3 Aug 2009 08:09:59 -0700
> 
> x86: Make 64-bit efi_ioremap use ioremap on MMIO regions
> 
> Booting current 64-bit x86 kernels on the latest Apple MacBook
> (MacBook5,2) via EFI gives the following warning:
> 
> [    0.182209] ------------[ cut here ]------------
> [    0.182222] WARNING: at arch/x86/mm/pageattr.c:581 __cpa_process_fault+0x44/0xa0()

This patch does not really fix the issue. __cpa_process_fault will warn
if target memory area is beyond max_pfn_mapped. EFI runtime RAM area
beyond max_pfn_mapped will trigger the warning too.

To fix the issue. I think we can loose the restriction of
__cpa_process_fault a little. Add a global variable max_pfn, which is
max pfn of all memory type (including RAM, RESERVED, etc, mapped or
unmapped), and __cpa_process_fault warns for memory area beyond max_pfn
only.

Best Regards,
Huang Ying