6.12-stable review patch. If anyone has any objections, please let me know.
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From: Tianyang Zhang zhangtianyang@loongson.cn
commit a073d637c8cfbfbab39b7272226a3fbf3b887580 upstream.
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: Liupu Wang wangliupu@loongson.cn Signed-off-by: Liupu Wang wangliupu@loongson.cn Signed-off-by: Tianyang Zhang zhangtianyang@loongson.cn Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/loongarch/include/asm/pgtable.h | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
--- a/arch/loongarch/include/asm/pgtable.h +++ b/arch/loongarch/include/asm/pgtable.h @@ -431,6 +431,9 @@ static inline unsigned long pte_accessib
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)); } @@ -565,9 +568,11 @@ static inline struct page *pmd_page(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)