[aarch64 boot-wrapper][PATCH] aarch64: Enable access to allocation tags if MTE is present

[aarch64 boot-wrapper][PATCH] aarch64: Enable access to allocation tags if MTE is present

[Catalin Marinas]

SCR_EL3.ATA must be set so that software can access the allocation
(in-memory) MTE tags.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
 arch/aarch64/boot.S | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/aarch64/boot.S b/arch/aarch64/boot.S
index fd7133d1725c..a9264de937be 100644
--- a/arch/aarch64/boot.S
+++ b/arch/aarch64/boot.S
@@ -61,6 +61,14 @@ _start:
 	cbz	x1, 1f
 
 	orr	x0, x0, #(1 << 27)		// FGT enable
+1:
+	/* Enable MTE if present */
+	mrs	x10, id_aa64pfr1_el1
+	ubfx	x10, x10, #8, #4
+	cmp	x10, #2
+	b.lt	1f
+
+	orr	x0, x0, #(1 << 26)		// ATA enable
 1:
 #ifndef KERNEL_32
 	orr	x0, x0, #(1 << 10)		// 64-bit EL2

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Re: [aarch64 boot-wrapper][PATCH] aarch64: Enable access to allocation tags if MTE is present

[Mark Rutland]

On Wed, May 05, 2021 at 10:38:55AM +0100, Catalin Marinas wrote:
> SCR_EL3.ATA must be set so that software can access the allocation
> (in-memory) MTE tags.
> 
> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Thanks; applied.

Mark.

> ---
>  arch/aarch64/boot.S | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/arch/aarch64/boot.S b/arch/aarch64/boot.S
> index fd7133d1725c..a9264de937be 100644
> --- a/arch/aarch64/boot.S
> +++ b/arch/aarch64/boot.S
> @@ -61,6 +61,14 @@ _start:
>  	cbz	x1, 1f
>  
>  	orr	x0, x0, #(1 << 27)		// FGT enable
> +1:
> +	/* Enable MTE if present */
> +	mrs	x10, id_aa64pfr1_el1
> +	ubfx	x10, x10, #8, #4
> +	cmp	x10, #2
> +	b.lt	1f
> +
> +	orr	x0, x0, #(1 << 26)		// ATA enable
>  1:
>  #ifndef KERNEL_32
>  	orr	x0, x0, #(1 << 10)		// 64-bit EL2

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