[PATCH 5/6] arm64: Add the arm64.nosme command line option

[Mark Brown]

On Mon, Jun 27, 2022 at 04:14:11PM +0100, Marc Zyngier wrote:

> +.Linit_sme:	/* SME register access and priority mapping */
> +	msr	cptr_el2, x0			// Disable SME traps
> +	bic	x0, x0, #CPTR_EL2_TSM
> +	msr	cptr_el2, x0

Should the first msr there be a mrs?  If not it should probably have a
comment explaining what it's doing.

> +	mov	x1, #0				// SMCR controls
> +
> +	mrs_s	x2, SYS_ID_AA64SMFR0_EL1
> +	ubfx	x2, x2, #ID_AA64SMFR0_FA64_SHIFT, #1 // Full FP in SM?
> +	cbz	x2, .Lskip_sme_fa64

I'm sure any firmware authors who enable SME will remember to also
enable FA64 if it's supported in their hardware!
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