linux-kernel - Re: [PATCH] ARM: OMAP: Use ARM SMC Calling Convention when OP-TEE is available

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Message-ID: <20191216210407.GR35479@atomide.com>
Date:   Mon, 16 Dec 2019 13:04:07 -0800
From:   Tony Lindgren <tony@...mide.com>
To:     "Andrew F. Davis" <afd@...com>
Cc:     Mark Rutland <mark.rutland@....com>, linux-omap@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ARM: OMAP: Use ARM SMC Calling Convention when OP-TEE is
 available

* Andrew F. Davis <afd@...com> [191216 20:57]:
> Looks like the TI quirk idea is not moving forward, even the QCOM quirk
> looks like it may get kicked out. arm_smccc_smc() will remain only for
> SMCCC compliant calls, but it looks like a generic arm_smc() wouldn't be
> too opposed upstream.

Yes so it seems.

> Either way this patch would still be valid as when OP-TEE is present
> then arm_smccc_smc() will be the right call to make, how we handle the
> legacy calls can be sorted out later if a generic SMC call is implemented.

Please see my comment regarding this patch earlier in this thread
pasted below for convenience:

* Tony Lindgren <tony@...mide.com> [191119 16:22]:
> In any case, you should do the necessary checks for HAVE_ARM_SMCCC
> only once during init. I'm not sure how much checking for
> "/firmware/optee" helps here, sounds like we have a broken system
> if the firmware is not there while the arm_smccc_smc() should
> still work just fine :)

So only check once during init. And during init, you should probably
also check that arm_smccc_smc() actually infd optee if
"/firmware/optee" is set, and only then set set the right function
pointer or some flag.

Regards,

Tony