[PATCH] armv8: cache_v8: Fix pgtables setup when MMU is already enabled

[PATCH] armv8: cache_v8: Fix pgtables setup when MMU is already enabled

[Pali Rohár]

When MMU is already enabled then dcache_enable() does not call mmu_setup()
and so setup_all_pgtables() is also never called.

In this situation when some driver calls mmu_set_region_dcache_behaviour()
function then U-Boot crashes with error message:

    Emergency page table not setup.

Fix this issue by explicitly calling setup_all_pgtables() in dcache_enable()
function near condition for mmu_setup().

This change fixes chainloading U-Boot from U-Boot on Turris Mox board which
uses mvneta ethernet driver which calls mmu_set_region_dcache_behaviour().

Signed-off-by: Pali Rohár <pali@kernel.org>
---
 arch/arm/cpu/armv8/cache_v8.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm/cpu/armv8/cache_v8.c b/arch/arm/cpu/armv8/cache_v8.c
index e4736e564366..2a226fd0633d 100644
--- a/arch/arm/cpu/armv8/cache_v8.c
+++ b/arch/arm/cpu/armv8/cache_v8.c
@@ -503,6 +503,10 @@ void dcache_enable(void)
 		mmu_setup();
 	}
 
+	/* Set up page tables only once (it is done also by mmu_setup()) */
+	if (!gd->arch.tlb_fillptr)
+		setup_all_pgtables();
+
 	set_sctlr(get_sctlr() | CR_C);
 }
 
-- 
2.20.1

Re: [PATCH] armv8: cache_v8: Fix pgtables setup when MMU is already enabled

[Marek Behún]

On Wed, 14 Sep 2022 13:37:46 +0200
Pali Rohár <pali@kernel.org> wrote:

> When MMU is already enabled then dcache_enable() does not call mmu_setup()
> and so setup_all_pgtables() is also never called.
> 
> In this situation when some driver calls mmu_set_region_dcache_behaviour()
> function then U-Boot crashes with error message:
> 
>     Emergency page table not setup.
> 
> Fix this issue by explicitly calling setup_all_pgtables() in dcache_enable()
> function near condition for mmu_setup().
> 
> This change fixes chainloading U-Boot from U-Boot on Turris Mox board which
> uses mvneta ethernet driver which calls mmu_set_region_dcache_behaviour().
> 
> Signed-off-by: Pali Rohár <pali@kernel.org>

Reviewed-by: Marek Behún <kabel@kernel.org>

Re: [PATCH] armv8: cache_v8: Fix pgtables setup when MMU is already enabled

[Stefan Roese]

On 14.09.22 13:37, Pali Rohár wrote:
> When MMU is already enabled then dcache_enable() does not call mmu_setup()
> and so setup_all_pgtables() is also never called.
> 
> In this situation when some driver calls mmu_set_region_dcache_behaviour()
> function then U-Boot crashes with error message:
> 
>      Emergency page table not setup.
> 
> Fix this issue by explicitly calling setup_all_pgtables() in dcache_enable()
> function near condition for mmu_setup().
> 
> This change fixes chainloading U-Boot from U-Boot on Turris Mox board which
> uses mvneta ethernet driver which calls mmu_set_region_dcache_behaviour().
> 
> Signed-off-by: Pali Rohár <pali@kernel.org>

Reviewed-by: Stefan Roese <sr@denx.de>

Thanks,
Stefan

> ---
>   arch/arm/cpu/armv8/cache_v8.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/arch/arm/cpu/armv8/cache_v8.c b/arch/arm/cpu/armv8/cache_v8.c
> index e4736e564366..2a226fd0633d 100644
> --- a/arch/arm/cpu/armv8/cache_v8.c
> +++ b/arch/arm/cpu/armv8/cache_v8.c
> @@ -503,6 +503,10 @@ void dcache_enable(void)
>   		mmu_setup();
>   	}
>   
> +	/* Set up page tables only once (it is done also by mmu_setup()) */
> +	if (!gd->arch.tlb_fillptr)
> +		setup_all_pgtables();
> +
>   	set_sctlr(get_sctlr() | CR_C);
>   }
>   

Viele Grüße,
Stefan Roese

-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-51 Fax: (+49)-8142-66989-80 Email: sr@denx.de

Re: [PATCH] armv8: cache_v8: Fix pgtables setup when MMU is already enabled

[Tom Rini]

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On Wed, Sep 14, 2022 at 01:37:46PM +0200, Pali Rohár wrote:

> When MMU is already enabled then dcache_enable() does not call mmu_setup()
> and so setup_all_pgtables() is also never called.
> 
> In this situation when some driver calls mmu_set_region_dcache_behaviour()
> function then U-Boot crashes with error message:
> 
>     Emergency page table not setup.
> 
> Fix this issue by explicitly calling setup_all_pgtables() in dcache_enable()
> function near condition for mmu_setup().
> 
> This change fixes chainloading U-Boot from U-Boot on Turris Mox board which
> uses mvneta ethernet driver which calls mmu_set_region_dcache_behaviour().
> 
> Signed-off-by: Pali Rohár <pali@kernel.org>
> Reviewed-by: Marek Behún <kabel@kernel.org>
> Reviewed-by: Stefan Roese <sr@denx.de>

Applied to u-boot/master, thanks!

-- 
Tom

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