linux-kernel - Re: [PATCH v3 18/26] coresight: etm4x: Clean up exception level masks

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Message-ID: <e385a0ff-90e5-de72-78c5-bf4344a854cd@arm.com>
Date:   Mon, 9 Nov 2020 09:44:04 +0000
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     Mathieu Poirier <mathieu.poirier@...aro.org>
Cc:     linux-arm-kernel@...ts.infradead.org, mike.leach@...aro.org,
        coresight@...ts.linaro.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 18/26] coresight: etm4x: Clean up exception level masks

On 11/6/20 6:52 PM, Mathieu Poirier wrote:
> Good morning,

Good morning.

> 
> On Wed, Oct 28, 2020 at 10:09:37PM +0000, Suzuki K Poulose wrote:
>> etm4_get_access_type() calculates the exception level bits
>> for use in address comparator registers. This is also used
>> by the TRCVICTLR register by shifting to the required position.
>>
>> This patch cleans up the logic to make etm4_get_access_type()
>> calcualte a generic mask which can be used by all users by
>> shifting to their field.
>>
>> No functional changes, only code cleanups.
>>
>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
>> ---
>> Changes since previous version:
>>    - Fix the duplicate shift. More commentary
>> ---

>> -/* access level control in TRCVICTLR - same bits as TRCACATRn but shifted */
>> -#define ETM_EXLEVEL_LSHIFT_TRCVICTLR	8
>> +/*
>> + * Exception level mask for Secure and Non-Secure ELs.
>> + * ETM defines the bits for EL control (e.g, TRVICTLR, TRCACTRn).
>> + * The Secure and Non-Secure ELs are always to gether.
>> + * Non-secure EL3 is never implemented.
>> + * We use the following generic mask as they appear in different
>> + * registers and this can be shifted for the appropriate
>> + * fields.
>> + */
>> +#define ETM_EXLEVEL_S_APP		BIT(0)	/* Secure EL0		*/
>> +#define ETM_EXLEVEL_S_OS		BIT(1)	/* Secure EL1		*/
>> +#define ETM_EXLEVEL_S_HYP		BIT(2)	/* Secure EL2		*/
>> +#define ETM_EXLEVEL_S_MON		BIT(3)	/* Secure EL3/Montor	*/
> 
> s/Montor/Monitor
> 

>> +#define ETM_EXLEVEL_NS_APP		BIT(4)	/* NonSecure EL0	*/
>> +#define ETM_EXLEVEL_NS_OS		BIT(5)	/* NonSecure EL1	*/
>> +#define ETM_EXLEVEL_NS_HYP		BIT(6)	/* NonSecure EL2	*/
>> +
>> +#define ETM_EXLEVEL_MASK		(GENMASK(6, 0))
> 
> Not used.
> 
>> +#define ETM_EXLEVEL_S_MASK		(GENMASK(3, 0))
>> +#define ETM_EXLEVEL_NS_MASK		(GENMASK(6, 4))
> 
> This needs to be GENMASK(2, 0) in order TRCVICTLR_EXLEVEL_NS_SHIFT to be 20.
> Otherwise the resulting mask is 4 bit off to the left.
> 



Will address the comments. Thanks for spotting the mistakes.

Suzuki