Re: [PATCH] ARMv7 Oprofile support

["mud dog" <muddogxp@xxxxxxxxx>]

Hi Jean

2008/9/5 Jean Pihet <jpihet@xxxxxxxxxx>:
> Hi Xinyu,
>
>> I have a question about ARMv6/v7 PMNC unit support.
>> Why there's no DBGEN or SPNIDEN bit settings in oprofile driver?
> Since there is no security framework in place from OMAP3 those bits are left
> untouched, so we are using the default values after boot.
> On the boards I have, OMAP3 is running in non secure mode (bit 18 of DSCR is
> 1).
>
> I do not think it is a good think to change those security related bits in the
> Oprofile code.

I think maybe there will be some security related codes or framework
in kernel in future?
Or just leave them in bootloader? We need control them somewhere.

>
> AFAIK all events are generated and processed by Oprofile.
>
>> Without these security enable bit, PMNC will not count for L1 events.
> Why would it be L1 events only? I think no event should be generated at all.

CPU_CYCLES can be generated without them.

>
>> One note from ARM1176 TRM below:
>>
>> 1. In Debug state the counter is disabled.
>> 2. When the core is in a mode where noninvasive debug is not
>> permitted, set by SPNIDEN and the SUNIDEN bit, see c1, Secure Debug
>> Enable Register, the processor does not count events.
>>
>> Best Regards
>> Xinyu
>>
>> 2008/7/1 Jean Pihet <jpihet@xxxxxxxxxx>
>>
>> > Hi,
>> >
>> > This patch adds Oprofile support on ARMv7, using the PMNC unit.
>> > Tested on OMAP3430 SDP and 3530 EVM.
>> >
>> > Feedback and comments are welcome.
>> >
>> > The patch to user space components will be sent asap to Oprofile
>> > maintainers at http://sourceforge.net/projects/oprofile/.
>> >
>> > Regards,
>> > Jean.
>> >
>



-- 
Best Regards
Muddog <http://muddogxp.cublog.cn>

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