Re: [PATCH v2 2/3] xen/arm: vsmc: Don't implement function ID that doesn't exist

[Julien Grall <julien.grall@linaro.org>]

On 02/06/2018 03:15 PM, Volodymyr Babchuk wrote:
> Hi Julien,

Hi,

> On 06.02.18 16:53, Julien Grall wrote:
>> On 02/02/2018 01:46 PM, Volodymyr Babchuk wrote:
>>>
>>>
>>> On 02.02.18 13:41, Julien Grall wrote:
>>>> The current implementation of SMCCC relies on the fact only function
>>>> number (bits [15:0]) is enough to identify what to implement.
>>>>
>>>> However, PSCI call are only available in the range 
>>>> 0x84000000-0x8400001F
>>>> and 0xC4000000-0xC400001F. Furthermore, not all SMC32 functions have
>>>> equivalent in the SMC64. This is the case of:
>>>>      * PSCI_VERSION
>>>>      * CPU_OFF
>>>>      * MIGRATE_INFO_TYPE
>>>>      * SYSTEM_OFF
>>>>      * SYSTEM_RESET
>>>>
>>>> Similarly call count, call uid, revision can only be query using 
>>>> smc32/hvc32
>>>> fast calls (See 6.2 in ARM DEN 0028B).
>>>>
>>>> Xen should only implement identifier existing in the specification in
>>>> order to avoid potential clash with later revision. Therefore rework 
>>>> the
>>>> vsmc code to use the whole function identifier rather than only the
>>>> function number.
>>>>
>>>> At the same time, the new macros for call count, call uid, revision are
>>>> renamed to better suit the spec.
>>>>
>>>> Lastly, update SSSC_SMCCC_FUNCTION_COUNT to match the correct number of
>>>> funtions. Note that version is not updated because the number has 
>>>> always
>>>> been wrong, and nobody could properly use it.
>>>>
>>>> Signed-off-by: Julien Grall <julien.grall@linaro.org>
>>>
>>> `Reviewed-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com>`
>>
>> Thank you for the reviewed-by. I noticed that you put ` at the 
>> beginning and end of the line in your reviewed-by tag so far. Is there 
>> any reason for that?
> 
> It is out of habit. You see, this is preferred way to add R-b tag at 
> GitHub (or at least in OP-TEE repos). Github uses Markdown, and text in 
> ` becomes formatted as a code. I do code review mostly at github,
> so it become a habit to add ` around R-b tags. You can ignore this, of 
> course. I'll try to omit ` in the future.

Oh, good to know. I am usually copying the full line and my editor was 
not happy at all with the `. For Xen, we tend to only have the 
Reviewed-by tag on a line.

Anyway, thank you for reviewing the series :). I will resend a version soon.

If you have time, you might want to have a look at "xen/arm: PSCI 1.1 
and SMCCC-1.1 support and XSA-254 variant 2 update" [1].

Cheers,

[1] https://lists.xen.org/archives/html/xen-devel/2018-02/msg00285.html

-- 
Julien Grall

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