On Mon, Aug 08, 2022 at 01:53:21PM +0100, Will Deacon wrote:
> From: Peter Collingbourne <pcc@xxxxxxxxxx>
>
> [ This issue was fixed upstream by accident in c3cee924bd85 ("arm64:
> head: cover entire kernel image in initial ID map") as part of a
> large refactoring of the arm64 boot flow. This simple fix is therefore
> preferred for -stable backporting ]
>
> On a system that implements FEAT_EPAN, read/write access to the idmap
> is denied because UXN is not set on the swapper PTEs. As a result,
> idmap_kpti_install_ng_mappings panics the kernel when accessing
> __idmap_kpti_flag. Fix it by setting UXN on these PTEs.
>
> Fixes: 18107f8a2df6 ("arm64: Support execute-only permissions with Enhanced PAN")
> Cc: <stable@xxxxxxxxxxxxxxx> # 5.15
> Link: https://linux-review.googlesource.com/id/Ic452fa4b4f74753e54f71e61027e7222a0fae1b1
> Signed-off-by: Peter Collingbourne <pcc@xxxxxxxxxx>
> Acked-by: Will Deacon <will@xxxxxxxxxx>
> Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Link: https://lore.kernel.org/r/20220719234909.1398992-1-pcc@xxxxxxxxxx
> Signed-off-by: Will Deacon <will@xxxxxxxxxx>
> ---
> arch/arm64/include/asm/kernel-pgtable.h | 4 ++--
> arch/arm64/kernel/head.S | 2 +-
> 2 files changed, 3 insertions(+), 3 deletions(-)
So this should be added to 5.15.y, 5.18.y, and 5.19.y? Or some subset?
thanks,
greg k-h
