From c25c4aa3f79a488cc270507935a29c07dc6bddfc Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Fri, 27 Feb 2026 18:53:06 +0000 Subject: [PATCH] arm64: mm: Add PTE_DIRTY back to PAGE_KERNEL* to fix kexec/hibernation Commit 143937ca51cc ("arm64, mm: avoid always making PTE dirty in pte_mkwrite()") changed pte_mkwrite_novma() to only clear PTE_RDONLY when PTE_DIRTY is set. This was to allow writable-clean PTEs for swap pages that haven't actually been written. However, this broke kexec and hibernation for some platforms. Both go through trans_pgd_create_copy() -> _copy_pte(), which calls pte_mkwrite_novma() to make the temporary linear-map copy fully writable. With the updated pte_mkwrite_novma(), read-only kernel pages (without PTE_DIRTY) remain read-only in the temporary mapping. While such behaviour is fine for user pages where hardware DBM or trapping will make them writeable, subsequent in-kernel writes by the kexec relocation code will fault. Add PTE_DIRTY back to all _PAGE_KERNEL* protection definitions. This was the case prior to 5.4, commit aa57157be69f ("arm64: Ensure VM_WRITE|VM_SHARED ptes are clean by default"). With the kernel linear-map PTEs always having PTE_DIRTY set, pte_mkwrite_novma() correctly clears PTE_RDONLY. Fixes: 143937ca51cc ("arm64, mm: avoid always making PTE dirty in pte_mkwrite()") Signed-off-by: Catalin Marinas Cc: stable@vger.kernel.org Reported-by: Jianpeng Chang Link: https://lore.kernel.org/r/20251204062722.3367201-1-jianpeng.chang.cn@windriver.com Cc: Will Deacon Cc: Huang, Ying Cc: Guenter Roeck Reviewed-by: Huang Ying Signed-off-by: Will Deacon --- arch/arm64/include/asm/pgtable-prot.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h index 2b32639160de..f560e6420267 100644 --- a/arch/arm64/include/asm/pgtable-prot.h +++ b/arch/arm64/include/asm/pgtable-prot.h @@ -50,11 +50,11 @@ #define _PAGE_DEFAULT (_PROT_DEFAULT | PTE_ATTRINDX(MT_NORMAL)) -#define _PAGE_KERNEL (PROT_NORMAL) -#define _PAGE_KERNEL_RO ((PROT_NORMAL & ~PTE_WRITE) | PTE_RDONLY) -#define _PAGE_KERNEL_ROX ((PROT_NORMAL & ~(PTE_WRITE | PTE_PXN)) | PTE_RDONLY) -#define _PAGE_KERNEL_EXEC (PROT_NORMAL & ~PTE_PXN) -#define _PAGE_KERNEL_EXEC_CONT ((PROT_NORMAL & ~PTE_PXN) | PTE_CONT) +#define _PAGE_KERNEL (PROT_NORMAL | PTE_DIRTY) +#define _PAGE_KERNEL_RO ((PROT_NORMAL & ~PTE_WRITE) | PTE_RDONLY | PTE_DIRTY) +#define _PAGE_KERNEL_ROX ((PROT_NORMAL & ~(PTE_WRITE | PTE_PXN)) | PTE_RDONLY | PTE_DIRTY) +#define _PAGE_KERNEL_EXEC ((PROT_NORMAL & ~PTE_PXN) | PTE_DIRTY) +#define _PAGE_KERNEL_EXEC_CONT ((PROT_NORMAL & ~PTE_PXN) | PTE_CONT | PTE_DIRTY) #define _PAGE_SHARED (_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_UXN | PTE_WRITE) #define _PAGE_SHARED_EXEC (_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_WRITE)