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s390/pgtable: Fix check for pgste/storage key handling

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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: Martin Schwidefky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
CC: stable@vger.kernel.org
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Christian Borntraeger 2013-05-27 16:19:55 +02:00 committed by Martin Schwidefsky
parent d5b4c2f493
commit b56433cb78
1 changed files with 11 additions and 4 deletions
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15
arch/s390/include/asm/pgtable.h
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@ -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;
}