[PATCH] arm64: Correct wrong label in macro __init_el2_gicv3

[PATCH] arm64: Correct wrong label in macro __init_el2_gicv3

[Joakim Tjernlund]

If GICv3 init fails, CPU branched to the wrong label causing
a crash much later.

Fixes: 114945d84a30a5fe ("arm64: Fix labels in el2_setup macros")
Signed-off-by: Joakim Tjernlund <joakim.tjernlund@infinera.com>
---
 arch/arm64/include/asm/el2_setup.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/el2_setup.h b/arch/arm64/include/asm/el2_setup.h
index 3198acb2aad8..7f3c87f7a0ce 100644
--- a/arch/arm64/include/asm/el2_setup.h
+++ b/arch/arm64/include/asm/el2_setup.h
@@ -106,7 +106,7 @@
 	msr_s	SYS_ICC_SRE_EL2, x0
 	isb					// Make sure SRE is now set
 	mrs_s	x0, SYS_ICC_SRE_EL2		// Read SRE back,
-	tbz	x0, #0, 1f			// and check that it sticks
+	tbz	x0, #0, .Lskip_gicv3_\@		// and check that it sticks
 	msr_s	SYS_ICH_HCR_EL2, xzr		// Reset ICC_HCR_EL2 to defaults
 .Lskip_gicv3_\@:
 .endm
-- 
2.32.0


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Re: [PATCH] arm64: Correct wrong label in macro __init_el2_gicv3

[Mark Rutland]

[Adding Ccs]

On Mon, Feb 14, 2022 at 06:11:57PM +0100, Joakim Tjernlund wrote:
> If GICv3 init fails, CPU branched to the wrong label causing
> a crash much later.

How about:

| In commit:
|
|   114945d84a30a5fe ("arm64: Fix labels in el2_setup macros")
|
| We renamed a label from '1' to '.Lskip_gicv3_\@', but failed to update
| a branch to it, which now targets a later label also called '1'.
|
| The branch is taken rarely, when GICv3 is present but SRE is disabled
| at EL3, causing a boot-time crash.
|
| Update the caller to the new label name.

... since that makes it clear that this is the right fix.

> Fixes: 114945d84a30a5fe ("arm64: Fix labels in el2_setup macros")
> Signed-off-by: Joakim Tjernlund <joakim.tjernlund@infinera.com>

With the wording above:

Reviewed-by: Mark Rutland <mark.rutland@arm.com>

Thanks,
Mark.

> ---
>  arch/arm64/include/asm/el2_setup.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/include/asm/el2_setup.h b/arch/arm64/include/asm/el2_setup.h
> index 3198acb2aad8..7f3c87f7a0ce 100644
> --- a/arch/arm64/include/asm/el2_setup.h
> +++ b/arch/arm64/include/asm/el2_setup.h
> @@ -106,7 +106,7 @@
>  	msr_s	SYS_ICC_SRE_EL2, x0
>  	isb					// Make sure SRE is now set
>  	mrs_s	x0, SYS_ICC_SRE_EL2		// Read SRE back,
> -	tbz	x0, #0, 1f			// and check that it sticks
> +	tbz	x0, #0, .Lskip_gicv3_\@		// and check that it sticks
>  	msr_s	SYS_ICH_HCR_EL2, xzr		// Reset ICC_HCR_EL2 to defaults
>  .Lskip_gicv3_\@:
>  .endm
> -- 
> 2.32.0
> 

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Re: [PATCH] arm64: Correct wrong label in macro __init_el2_gicv3

[Marc Zyngier]

[+ Catalin, Will]

On Mon, 14 Feb 2022 17:11:57 +0000,
Joakim Tjernlund <joakim.tjernlund@infinera.com> wrote:
> 
> If GICv3 init fails, CPU branched to the wrong label causing
> a crash much later.
> 
> Fixes: 114945d84a30a5fe ("arm64: Fix labels in el2_setup macros")
> Signed-off-by: Joakim Tjernlund <joakim.tjernlund@infinera.com>

This deserves a

Cc: stable@vger.kernel.org

> ---
>  arch/arm64/include/asm/el2_setup.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/include/asm/el2_setup.h b/arch/arm64/include/asm/el2_setup.h
> index 3198acb2aad8..7f3c87f7a0ce 100644
> --- a/arch/arm64/include/asm/el2_setup.h
> +++ b/arch/arm64/include/asm/el2_setup.h
> @@ -106,7 +106,7 @@
>  	msr_s	SYS_ICC_SRE_EL2, x0
>  	isb					// Make sure SRE is now set
>  	mrs_s	x0, SYS_ICC_SRE_EL2		// Read SRE back,
> -	tbz	x0, #0, 1f			// and check that it sticks
> +	tbz	x0, #0, .Lskip_gicv3_\@		// and check that it sticks
>  	msr_s	SYS_ICH_HCR_EL2, xzr		// Reset ICC_HCR_EL2 to defaults
>  .Lskip_gicv3_\@:
>  .endm

Nice catch!

Reviewed-by: Marc Zyngier <maz@kernel.org>

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.

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