Subject: [PATCH v4 25/28] ARM: decompressor: Remove __hyp_get_vectors usage

From: [email-masked] (Christoffer Dall)
Date: Fri, 24 Mar 2017 15:34:40 +0100

On Tue, Mar 21, 2017 at 07:20:55PM +0000, Marc Zyngier wrote:
> When the compressed image needs to be relocated to avoid being
> overwritten by the decompression process, we need to relocate
> the hyp vectors as well so that we can find them once the
> decompression has taken effect.
> 
> For that, we perform the following calculation:
> 	u32 v = __hyp_get_vectors();
> 	v += offset;
> 	__hyp_set_vectors(v);
> 
> But we're guaranteed that the initial value of v as returned by
> __hyp_get_vectors is always __hyp_stub_vectors, because we have
> just set it by calling __hyp_stub_install.
> 
> So let's remove the use of __hyp_get_vectors, and directly use
> __hyp_stub_vectors instead.
> 
> Acked-by: Russell King <[email-masked]>
> Signed-off-by: Marc Zyngier <[email-masked]>
> ---
>  arch/arm/boot/compressed/head.S | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
> index 9150f9732785..d58bb104c6e8 100644
> --- a/arch/arm/boot/compressed/head.S
> +++ b/arch/arm/boot/compressed/head.S
> @@ -422,7 +422,10 @@ dtb_check_done:
>  		cmp	r0, #HYP_MODE
>  		bne	1f
>  
> -		bl	__hyp_get_vectors
> +0:		adr	r0, 0b
> +		movw	r1, #:lower16:__hyp_stub_vectors - 0b
> +		movt	r1, #:upper16:__hyp_stub_vectors - 0b
> +		add	r0, r0, r1

nit: you could add a comment explaining what r0 ends up containing,
because I'm pretty sure this will feel obscure when not read in the
context of this series with your commit message above.

>  		sub	r0, r0, r5
>  		add	r0, r0, r10
>  		bl	__hyp_set_vectors
> -- 
> 2.11.0

Nevertheless:

Acked-by: Christoffer Dall <[email-masked]>