Re: [PATCH 0/7] ARM: Map sections RO/XN

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Hello Sascha,

On 6/13/25 09:58, Sascha Hauer wrote:
> So far we mapped all RAM as read write with execute permission. This
> series series hardens this a bit. The barebox text segment will be
> mapped readonly with execute permission, the RO data section as readonly
> without execute permission and the remaining RAM will lose its execute
> permission.

Very nice. Thanks for working on this.

> I tested this series on ARMv7 and ARMv8. I am not confident though that
> there are no regressions, so this new behaviour is behind a Kconfig
> option. It is default-y, but can be disabled for debugging purposses.
> Once this series has proven stable it can be removed.
> 
> I haven't tested it on ARMv4-v6 due to the lack of hardware. I tried on
> Qemu, but the write protection did not work as expected. This should be
> resolved before merging.

I will give it a try and see what I find.

Cheers,
Ahmad

> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
> Sascha Hauer (7):
>       memory: request RO data section as separate region
>       ARM: pass barebox base to mmu_early_enable()
>       ARM: mmu: move ARCH_MAP_WRITECOMBINE to header
>       ARM: MMU: map memory for barebox proper pagewise
>       ARM: MMU: map text segment ro and data segments execute never
>       ARM: MMU64: map memory for barebox proper pagewise
>       ARM: MMU64: map text segment ro and data segments execute never
> 
>  arch/arm/Kconfig                 |  12 +++++
>  arch/arm/cpu/mmu-common.h        |   4 ++
>  arch/arm/cpu/mmu_32.c            |  86 +++++++++++++++++++++++++++------
>  arch/arm/cpu/mmu_64.c            | 101 +++++++++++++++++++++++++++++++++++----
>  arch/arm/cpu/uncompress.c        |   9 ++--
>  arch/arm/include/asm/mmu.h       |   2 +-
>  arch/arm/include/asm/pgtable64.h |   1 +
>  arch/arm/lib32/barebox.lds.S     |   3 +-
>  arch/arm/lib64/barebox.lds.S     |   5 +-
>  common/memory.c                  |   6 ++-
>  include/mmu.h                    |   1 +
>  11 files changed, 198 insertions(+), 32 deletions(-)
> ---
> base-commit: 340e930140e76827cf5cac731e6afe2836e28242
> change-id: 20250613-arm-mmu-xn-ro-1a1d996496ae
> 
> Best regards,

-- 
Pengutronix e.K.                  |                             |
Steuerwalder Str. 21              | http://www.pengutronix.de/  |
31137 Hildesheim, Germany         | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686  | Fax:   +49-5121-206917-5555 |