arm64: mm: Add PTE_DIRTY back to PAGE_KERNEL* to fix kexec/hibernation

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commit c25c4aa3f7 upstream.

Commit 143937ca51 ("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 aa57157be6 ("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: 143937ca51 ("arm64, mm: avoid always making PTE dirty in pte_mkwrite()")
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: stable@vger.kernel.org
Reported-by: Jianpeng Chang <jianpeng.chang.cn@windriver.com>
Link: https://lore.kernel.org/r/20251204062722.3367201-1-jianpeng.chang.cn@windriver.com
Cc: Will Deacon <will@kernel.org>
Cc: Huang, Ying <ying.huang@linux.alibaba.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Huang Ying <ying.huang@linux.alibaba.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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This commit is contained in:

Catalin Marinas 2026-02-27 18:53:06 +00:00 • committed by Greg Kroah-Hartman

parent ad8fa5bff5

commit 439b5fb728

1 changed files with 5 additions and 5 deletions

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arch/arm64/include/asm/pgtable-prot.h

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