[RFC:PATCH 02/03] powerpc: Add definitions for Debug Registers on BookE Platforms

[Kumar Gala]

On Dec 10, 2009, at 9:28 PM, David Gibson wrote:

> On Thu, Dec 10, 2009 at 08:41:53PM -0600, Kumar Gala wrote:
> [snip]
>>> +#define DBCR1_USER_DEBUG	(DBCR1_IAC12M | DBCR1_IAC34M)
>>> +#define DBCR1_BASE_REG_VALUE	(DBCR1_IAC1US | DBCR1_IAC1ER_10 | \
>>> +				 DBCR1_IAC2US | DBCR1_IAC2ER_10 | \
>>> +				 DBCR1_IAC3US | DBCR1_IAC3ER_10 | \
>>> +				 DBCR1_IAC4US | DBCR1_IAC4ER_10)
>> 
>> We are we using MSR[IS] IS=0, why not just any Eff address?  In the
>> future we might have user as IS = 1, and kernel as IS = 0.
> 
> Since the user can't control that directly, we can update this when
> and if we change our use of address spaces.

That's such a subtle issue (easy to forgot about and miss in the future).  Why do we need this now?

- k