[PATCH v1] arm64: mm: fix resume for 52-bit enabled builds

[PATCH v1] arm64: mm: fix resume for 52-bit enabled builds

[Joey Gouly]

__cpu_setup() was changed to take the actual number of VA bits in x0,
however the resume path was not updated at the same time.

Load `vabits_actual` in the resume path, to ensure that the correct
number of VA bits is used.

This fixes booting v6.0-rc kernels on my Juno.

Fixes: 0aaa68532e9d ("arm64: mm: fix booting with 52-bit address space")
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/kernel/sleep.S | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S
index 617f78ad43a1..97c9de57725d 100644
--- a/arch/arm64/kernel/sleep.S
+++ b/arch/arm64/kernel/sleep.S
@@ -101,6 +101,9 @@ SYM_FUNC_END(__cpu_suspend_enter)
 SYM_CODE_START(cpu_resume)
 	bl	init_kernel_el
 	bl	finalise_el2
+#if VA_BITS > 48
+	ldr_l	x0, vabits_actual
+#endif
 	bl	__cpu_setup
 	/* enable the MMU early - so we can access sleep_save_stash by va */
 	adrp	x1, swapper_pg_dir
-- 
2.17.1


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Re: [PATCH v1] arm64: mm: fix resume for 52-bit enabled builds

[Ard Biesheuvel]

On Fri, 9 Sept 2022 at 10:38, Joey Gouly <joey.gouly@arm.com> wrote:
>
> __cpu_setup() was changed to take the actual number of VA bits in x0,
> however the resume path was not updated at the same time.
>
> Load `vabits_actual` in the resume path, to ensure that the correct
> number of VA bits is used.
>
> This fixes booting v6.0-rc kernels on my Juno.
>
> Fixes: 0aaa68532e9d ("arm64: mm: fix booting with 52-bit address space")
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Ard Biesheuvel <ardb@kernel.org>

Yup. I missed that one - thanks for fixing it.

Acked-by: Ard Biesheuvel <ardb@kernel.org>

> ---
>  arch/arm64/kernel/sleep.S | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S
> index 617f78ad43a1..97c9de57725d 100644
> --- a/arch/arm64/kernel/sleep.S
> +++ b/arch/arm64/kernel/sleep.S
> @@ -101,6 +101,9 @@ SYM_FUNC_END(__cpu_suspend_enter)
>  SYM_CODE_START(cpu_resume)
>         bl      init_kernel_el
>         bl      finalise_el2
> +#if VA_BITS > 48
> +       ldr_l   x0, vabits_actual
> +#endif
>         bl      __cpu_setup
>         /* enable the MMU early - so we can access sleep_save_stash by va */
>         adrp    x1, swapper_pg_dir
> --
> 2.17.1
>

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Re: [PATCH v1] arm64: mm: fix resume for 52-bit enabled builds

[Will Deacon]

Hi Joey,

On Fri, Sep 09, 2022 at 09:38:11AM +0100, Joey Gouly wrote:
> __cpu_setup() was changed to take the actual number of VA bits in x0,
> however the resume path was not updated at the same time.
> 
> Load `vabits_actual` in the resume path, to ensure that the correct
> number of VA bits is used.
> 
> This fixes booting v6.0-rc kernels on my Juno.
> 
> Fixes: 0aaa68532e9d ("arm64: mm: fix booting with 52-bit address space")
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Ard Biesheuvel <ardb@kernel.org>

I can't apply this without your SoB line.

I think you made this mistake in the past, so please could you try to
fix your setup? There's probably a better way to do this, but I up having:

[commit]
        template = ~/linux-commit.template

in my .gitconfig, and then I put the SoB line in the template so it's
always there when I start writing the commit message.

Cheers,

Will

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