[PATCH v1 0/6] Fix page permission on arm64 architectures

[Simon Glass]

Hi Ilias,

On Wed, 5 Feb 2025 at 00:17, Ilias Apalodimas
<ilias.apalodimas at linaro.org> wrote:
>
> Hi!
> This is v1 of [0].
>
> This is an attempt to map the U-Boot binary properly, but leave the
> area we load binaries unaffected and RWX.
>
> There's a few changes since the RFC
> - Fixed the alignment of meminfo command when printing regions
> - 'meminfo' now prints arch specific attributes e.g PXN, UXN etc for arm
>   instead of RW, RO, RX
> - Since we don't set the permissions of EFI runtime services yet and keep
>   them as RWX, I removed the linker alignment changes which makes patch #3
>   easier to review. It's worth noting that qemu-arm sbsa was crashing with
>   the efi services page aligned. This is probably due to a mismatch of
>   memory, since the crash is only reproducible with QEMU instances that
>   have < 2 GB of RAM. I'll fix that along with the efi runtime services
> - Defined memory attribute changes properly with an enum for RW, RO, RX
>   instead of the hardcoded '1,2,3' I had on the RFC
> - Enabling mappings is now under a Kconfig (CONFIG_MMU_PGPROT), since
>   peope reported crashes when testing this, which are orthogonal to this
>   patch. We still have places in U-Boot where we define and later write
>   const variables. This will lead to a crash now as const variables are
>   properly managed and places in RO memory
> - Split patches to be easier to review
> - Added a patch updating 'meminfo'
> - Picked up acked-by tags from Jerome
>
> patch #1 adds printing capabilities for page mappings in 'meminfo'
> patch #2 adds documention in 'meminfo' command
> patch #3 prepares linker scripts, aligns sections in page boundaries etc
> patch #4 prepares an internal function to change the PTEs
> patch #5 adds function definitions & stubs for all archs
> patch #6 wires up the changes in U-Boot after it relocates
>
> [0] https://lore.kernel.org/u-boot/20250130072100.27297-1-ilias.apalodimas@linaro.org/
>
> Ilias Apalodimas (6):
>   meminfo: add memory details for armv8
>   doc: update meminfo with arch specific information
>   arm: Prepare linker scripts for memory permissions
>   arm64: mmu_change_region_attr() add an option not to break PTEs
>   treewide: Add a function to change page permissions
>   arm64: Enable RW, RX and RO mappings for the relocated binary
>
>  arch/arc/lib/cache.c                    |  2 +
>  arch/arm/cpu/arm926ejs/cache.c          |  2 +
>  arch/arm/cpu/armv7/cache_v7.c           |  1 +
>  arch/arm/cpu/armv7m/cache.c             |  2 +
>  arch/arm/cpu/armv8/cache_v8.c           | 54 +++++++++++++++++--
>  arch/arm/cpu/armv8/fsl-layerscape/cpu.c | 10 ++--
>  arch/arm/cpu/armv8/u-boot.lds           | 29 +++++-----
>  arch/arm/include/asm/armv8/mmu.h        |  2 +
>  arch/arm/include/asm/system.h           | 11 +++-
>  arch/arm/lib/cache.c                    |  2 +
>  arch/arm/mach-snapdragon/board.c        |  2 +-
>  arch/m68k/lib/cache.c                   |  2 +
>  arch/nios2/lib/cache.c                  |  2 +
>  arch/powerpc/lib/cache.c                |  2 +
>  arch/riscv/lib/cache.c                  |  2 +
>  arch/sh/cpu/sh4/cache.c                 |  2 +
>  arch/xtensa/lib/cache.c                 |  2 +
>  cmd/meminfo.c                           |  5 ++
>  common/Kconfig                          | 13 +++++
>  common/board_r.c                        | 20 +++++++
>  doc/usage/cmd/meminfo.rst               | 71 ++++++++++++++++++-------
>  include/asm-generic/sections.h          |  2 +
>  include/cpu_func.h                      | 16 ++++++
>  23 files changed, 215 insertions(+), 41 deletions(-)
>
> --
> 2.47.2
>

Can you please explain what problem this fixes, in your cover letter,
to match your series subject? I don't doubt there is a big problem,
but I'm not sure what it is?

Regards,
Simon