Commit a073d637 authored by Tianyang Zhang's avatar Tianyang Zhang Committed by Huacai Chen
Browse files

LoongArch: Let {pte,pmd}_modify() record the status of _PAGE_DIRTY 



Now if the PTE/PMD is dirty with _PAGE_DIRTY but without _PAGE_MODIFIED,
after {pte,pmd}_modify() we lose _PAGE_DIRTY, then {pte,pmd}_dirty()
return false and lead to data loss. This can happen in certain scenarios
such as HW PTW doesn't set _PAGE_MODIFIED automatically, so here we need
_PAGE_MODIFIED to record the dirty status (_PAGE_DIRTY).

The new modification involves checking whether the original PTE/PMD has
the _PAGE_DIRTY flag. If it exists, the _PAGE_MODIFIED bit is also set,
ensuring that the {pte,pmd}_dirty() interface can always return accurate
information.

Cc: stable@vger.kernel.org
Co-developed-by: default avatarLiupu Wang <wangliupu@loongson.cn>
Signed-off-by: default avatarLiupu Wang <wangliupu@loongson.cn>
Signed-off-by: default avatarTianyang Zhang <zhangtianyang@loongson.cn>
parent ce5ad03e

arch/loongarch/include/asm/pgtable.h

+8 −3
Original line number Diff line number Diff line
@@ -424,6 +424,9 @@ static inline unsigned long pte_accessible(struct mm_struct *mm, pte_t a) 


static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)

{

	if (pte_val(pte) & _PAGE_DIRTY)

		pte_val(pte) |= _PAGE_MODIFIED;



	return __pte((pte_val(pte) & _PAGE_CHG_MASK) |

		     (pgprot_val(newprot) & ~_PAGE_CHG_MASK));

}
@@ -547,9 +550,11 @@ static inline struct page *pmd_page(pmd_t pmd) 


static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)

{

	pmd_val(pmd) = (pmd_val(pmd) & _HPAGE_CHG_MASK) |

				(pgprot_val(newprot) & ~_HPAGE_CHG_MASK);

	return pmd;

	if (pmd_val(pmd) & _PAGE_DIRTY)

		pmd_val(pmd) |= _PAGE_MODIFIED;



	return __pmd((pmd_val(pmd) & _HPAGE_CHG_MASK) |

		     (pgprot_val(newprot) & ~_HPAGE_CHG_MASK));

}



static inline pmd_t pmd_mkinvalid(pmd_t pmd)