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Commit b56433cb authored by Christian Borntraeger's avatar Christian Borntraeger Committed by Martin Schwidefsky
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s390/pgtable: Fix check for pgste/storage key handling 



pte_present might return true on PAGE_TYPE_NONE, even if
the invalid bit is on. Modify the existing check of the
pgste functions to avoid crashes.

[ Martin Schwidefsky: added ptep_modify_prot_[start|commit] bits ]

Reported-by: default avatarMartin Schwidefky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
CC: stable@vger.kernel.org
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent d5b4c2f4

arch/s390/include/asm/pgtable.h

+11 −4
Original line number Diff line number Diff line
@@ -646,7 +646,7 @@ static inline pgste_t pgste_update_all(pte_t *ptep, pgste_t pgste) 
	unsigned long address, bits;

	unsigned char skey;



	if (!pte_present(*ptep))

	if (pte_val(*ptep) & _PAGE_INVALID)

		return pgste;

	address = pte_val(*ptep) & PAGE_MASK;

	skey = page_get_storage_key(address);
@@ -680,7 +680,7 @@ static inline pgste_t pgste_update_young(pte_t *ptep, pgste_t pgste) 
#ifdef CONFIG_PGSTE

	int young;



	if (!pte_present(*ptep))

	if (pte_val(*ptep) & _PAGE_INVALID)

		return pgste;

	/* Get referenced bit from storage key */

	young = page_reset_referenced(pte_val(*ptep) & PAGE_MASK);
@@ -706,7 +706,7 @@ static inline void pgste_set_key(pte_t *ptep, pgste_t pgste, pte_t entry) 
	unsigned long address;

	unsigned long okey, nkey;



	if (!pte_present(entry))

	if (pte_val(entry) & _PAGE_INVALID)

		return;

	address = pte_val(entry) & PAGE_MASK;

	okey = nkey = page_get_storage_key(address);
@@ -1098,6 +1098,9 @@ static inline pte_t ptep_modify_prot_start(struct mm_struct *mm, 
	pte = *ptep;

	if (!mm_exclusive(mm))

		__ptep_ipte(address, ptep);



	if (mm_has_pgste(mm))

		pgste = pgste_update_all(&pte, pgste);

	return pte;

}
@@ -1105,9 +1108,13 @@ static inline void ptep_modify_prot_commit(struct mm_struct *mm, 
					   unsigned long address,

					   pte_t *ptep, pte_t pte)

{

	pgste_t pgste;



	if (mm_has_pgste(mm)) {

		pgste = *(pgste_t *)(ptep + PTRS_PER_PTE);

		pgste_set_key(ptep, pgste, pte);

		pgste_set_pte(ptep, pte);

		pgste_set_unlock(ptep, *(pgste_t *)(ptep + PTRS_PER_PTE));

		pgste_set_unlock(ptep, pgste);

	} else

		*ptep = pte;

}