| From 775871d4be0d75e219cca937af843a4a1b60489a Mon Sep 17 00:00:00 2001 |
| From: Peter Collingbourne <pcc@google.com> |
| Date: Mon, 8 Aug 2022 13:53:21 +0100 |
| Subject: [PATCH] arm64: set UXN on swapper page tables |
| Git-commit: 775871d4be0d75e219cca937af843a4a1b60489a |
| Patch-mainline: v5.15.60 |
| References: git-fixes |
| |
| [ 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/Ic452fa4b4f74753e54f71e61027e7222a0fae1b1 |
| 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> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| Acked-by: Takashi Iwai <tiwai@suse.de> |
| |
| |
| arch/arm64/include/asm/kernel-pgtable.h | 4 ++-- |
| arch/arm64/kernel/head.S | 2 +- |
| 2 files changed, 3 insertions(+), 3 deletions(-) |
| |
| diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h |
| index 96dc0f7da258..a971d462f531 100644 |
| |
| |
| @@ -103,8 +103,8 @@ |
| /* |
| * Initial memory map attributes. |
| */ |
| -#define SWAPPER_PTE_FLAGS (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED) |
| -#define SWAPPER_PMD_FLAGS (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S) |
| +#define SWAPPER_PTE_FLAGS (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED | PTE_UXN) |
| +#define SWAPPER_PMD_FLAGS (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S | PMD_SECT_UXN) |
| |
| #if ARM64_KERNEL_USES_PMD_MAPS |
| #define SWAPPER_MM_MMUFLAGS (PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS) |
| diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S |
| index 17962452e31d..ab6566bf1c33 100644 |
| |
| |
| @@ -285,7 +285,7 @@ SYM_FUNC_START_LOCAL(__create_page_tables) |
| subs x1, x1, #64 |
| b.ne 1b |
| |
| - mov x7, SWAPPER_MM_MMUFLAGS |
| + mov_q x7, SWAPPER_MM_MMUFLAGS |
| |
| /* |
| * Create the identity mapping. |
| -- |
| 2.35.3 |
| |