[U-Boot] [PATCH] arm: fix hvc call

Alexander Graf agraf at suse.de
Tue Feb 19 12:41:17 UTC 2019


On 02/19/2019 08:38 AM, Ibai Erkiaga Elorza wrote:
> Hi Alexander,
>
>> -----Original Message-----
>> From: Alexander Graf <agraf at suse.de>
>> Sent: 18 February 2019 13:50
>> To: Ibai Erkiaga Elorza <IBAIE at xilinx.com>; u-boot at lists.denx.de
>> Cc: Sumit Garg <sumit.garg at linaro.org>; Heinrich Schuchardt
>> <xypron.glpk at gmx.de>; Tom Rini <trini at konsulko.com>; Albert Aribaud
>> <albert.u.boot at aribaud.net>
>> Subject: Re: [PATCH] arm: fix hvc call
>>
>>
>>
>> On 18.02.19 14:10, Ibai Erkiaga wrote:
>>> HVC call makes use of 6 arguments rather than 7 in the same way as SMC
>>> calls. The 7th argument is optional for both HVC and SMC but is
>>> implemented as 16-bit parameter and register R7 or W7.
>> The patch description is lacking a bit more context. Why not change SMC to also
>> include x7?
>>
> Definitively both approaches might be valid. The aim of the patch is just avoid compilation error due to an invalid asm code in the HVC call so that's why I'm removing the 7th argument. The Client ID (7th argument) could be used either for SMC or HVC but I don't have a testcase for it and seems that nobody is using up to date.

All of the above should be mentioned in the commit message, so that 
someone stumbling over the patch in 2 years will understand its rationale.


Alex



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