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Message-ID: <4B9A6D79.6040306@caviumnetworks.com>
Date:   Fri, 12 Mar 2010 08:36:09 -0800
From:   David Daney <ddaney@caviumnetworks.com>
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To:     Thomas Bogendoerfer <tsbogend@alpha.franken.de>
CC:     Wu Zhangjin <wuzhangjin@gmail.com>,
        Ralf Baechle <ralf@linux-mips.org>,
        Steven Rostedt <srostedt@redhat.com>, linux-mips@linux-mips.org
Subject: Re: [PATCH] MIPS: tracing: Optimize the implementation
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On 03/12/2010 12:50 AM, Thomas Bogendoerfer wrote:
> On Fri, Mar 12, 2010 at 02:07:37AM +0800, Wu Zhangjin wrote:
>> +/*
>> + * If the Instruction Pointer is in module space (0xc0000000), return ture;
>> + * otherwise, it is in kernel space (0x80000000), return false.
>> + */
>> +#define in_module(ip) (unlikely((ip)&  0x40000000))
>> +
>
> looks broken for 64bit, but maybe this is a 32bit only feature...
>

I initially thought the same thing.  However for 64-bit kernels linked 
in ckseg0 it is still true.  If we use the -msym32 optimization, we are 
forced to be in the ckseg space, so for most cases it works.

David Daney.