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Commit 82d34008 authored by Catalin Marinas's avatar Catalin Marinas
Browse files

arm64: Improve error reporting on set_pte_at() checks 



Currently the BUG_ON() checks do not give enough information about the
PTEs being set. This patch changes BUG_ON to WARN_ONCE and dumps the
values of the old and new PTEs. In addition, the checks are only made if
the new PTE entry is valid.

Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Reported-by: default avatarMing Lei <tom.leiming@gmail.com>
Cc: Will Deacon <will.deacon@arm.com>
parent 98fb7548

arch/arm64/include/asm/pgtable.h

+8 −4
Original line number Diff line number Diff line
@@ -276,10 +276,14 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, 
	 * hardware updates of the pte (ptep_set_access_flags safely changes

	 * valid ptes without going through an invalid entry).

	 */

	if (IS_ENABLED(CONFIG_DEBUG_VM) && IS_ENABLED(CONFIG_ARM64_HW_AFDBM) &&

	    pte_valid(*ptep)) {

		BUG_ON(!pte_young(pte));

		BUG_ON(pte_write(*ptep) && !pte_dirty(pte));

	if (IS_ENABLED(CONFIG_ARM64_HW_AFDBM) &&

	    pte_valid(*ptep) && pte_valid(pte)) {

		VM_WARN_ONCE(!pte_young(pte),

			     "%s: racy access flag clearing: 0x%016llx -> 0x%016llx",

			     __func__, pte_val(*ptep), pte_val(pte));

		VM_WARN_ONCE(pte_write(*ptep) && !pte_dirty(pte),

			     "%s: racy dirty state clearing: 0x%016llx -> 0x%016llx",

			     __func__, pte_val(*ptep), pte_val(pte));

	}



	set_pte(ptep, pte);