On Mon, Aug 08, 2022 at 01:53:21PM +0100, Will Deacon wrote:
From: Peter Collingbourne pcc@google.com
[ 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@vger.kernel.org # 5.15 Link: https://linux-review.googlesource.com/id/Ic452fa4b4f74753e54f71e61027e7222a0... Signed-off-by: Peter Collingbourne pcc@google.com Acked-by: Will Deacon will@kernel.org Cc: Ard Biesheuvel ardb@kernel.org Cc: Catalin Marinas catalin.marinas@arm.com Link: https://lore.kernel.org/r/20220719234909.1398992-1-pcc@google.com Signed-off-by: Will Deacon will@kernel.org
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