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s390/mm: return key via pointer in get_guest_storage_key

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Let's just split returning the key and reporting errors. This makes calling
code easier and avoids bugs as happened already.

Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit is contained in:
David Hildenbrand
2016-05-09 11:22:34 +02:00
committed by Christian Borntraeger
parent 8d6037a7b4
commit 154c8c19c3
3 changed files with 10 additions and 13 deletions
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12
arch/s390/mm/pgtable.c
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@@ -539,9 +539,9 @@ int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
}
EXPORT_SYMBOL(set_guest_storage_key);
unsigned long get_guest_storage_key(struct mm_struct *mm, unsigned long addr)
int get_guest_storage_key(struct mm_struct *mm, unsigned long addr,
unsigned char *key)
{
unsigned char key;
spinlock_t *ptl;
pgste_t pgste;
pte_t *ptep;
@@ -551,14 +551,14 @@ unsigned long get_guest_storage_key(struct mm_struct *mm, unsigned long addr)
return -EFAULT;
pgste = pgste_get_lock(ptep);
key = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
*key = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
if (!(pte_val(*ptep) & _PAGE_INVALID))
key = page_get_storage_key(pte_val(*ptep) & PAGE_MASK);
*key = page_get_storage_key(pte_val(*ptep) & PAGE_MASK);
/* Reflect guest's logical view, not physical */
key |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48;
*key |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48;
pgste_set_unlock(ptep, pgste);
pte_unmap_unlock(ptep, ptl);
return key;
return 0;
}
EXPORT_SYMBOL(get_guest_storage_key);
#endif