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Date: Wed, 17 Feb 2016 13:33:32 +0530
From: Anshuman Khandual <khandual@linux.vnet.ibm.com>
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To: Balbir Singh <bsingharora@gmail.com>, Paul Mackerras <paulus@ozlabs.org>
CC: linuxppc-dev@lists.ozlabs.org
Subject: Re: Fix BUG_ON() reporting in real mode on powerpc
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On 02/17/2016 12:46 PM, Balbir Singh wrote:
>> > It might be a little better to do this:
>> > 
>> > 		bugaddr = regs->nip;
>> > 		if (REGION_ID(bugaddr) == 0 && !(regs->msr & MSR_IR))
>> > 			bugaddr += PAGE_OFFSET;
>> > 
>> > It is possible to execute from addresses with the 0xc000... on top in
>> > real mode, because the CPU ignores the top 4 address bits in real
>> > mode.
> Good catch! Thank you
> 
> Changelog:
>      Don't add PAGE_OFFSET blindly, check if REGION_ID is 0

Cant we use USER_REGION_ID directly ?