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

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


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:
     * CPU_OFF

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@xxxxxxxxxx>

`Reviewed-by: Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>`

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].


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

Julien Grall

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