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KVM: s390: Adding skey bit to mmu context

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For lazy storage key handling, we need a mechanism to track if the
process ever issued a storage key operation.

This patch adds the basic infrastructure for making the storage
key handling optional, but still leaves it enabled for now by default.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit is contained in:
Dominik Dingel 2014-01-14 15:02:11 +01:00 committed by Christian Borntraeger
parent 0f689a33ad
commit 65eef33550
3 changed files with 30 additions and 14 deletions
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2
arch/s390/include/asm/mmu.h
View File

@ -16,6 +16,8 @@ typedef struct {
unsigned long vdso_base;
/* The mmu context has extended page tables. */
unsigned int has_pgste:1;
/* The mmu context uses storage keys. */
unsigned int use_skey:1;
} mm_context_t;
#define INIT_MM_CONTEXT(name) \

1
arch/s390/include/asm/mmu_context.h
View File

@ -23,6 +23,7 @@ static inline int init_new_context(struct task_struct *tsk,
mm->context.asce_bits |= _ASCE_TYPE_REGION3;
#endif
mm->context.has_pgste = 0;
mm->context.use_skey = 1;
mm->context.asce_limit = STACK_TOP_MAX;
crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
return 0;

41
arch/s390/include/asm/pgtable.h
View File

@ -466,6 +466,16 @@ static inline int mm_has_pgste(struct mm_struct *mm)
#endif
return 0;
}
static inline int mm_use_skey(struct mm_struct *mm)
{
#ifdef CONFIG_PGSTE
if (mm->context.use_skey)
return 1;
#endif
return 0;
}
/*
* pgd/pmd/pte query functions
*/
@ -699,12 +709,13 @@ static inline void pgste_set(pte_t *ptep, pgste_t pgste)
#endif
}
static inline pgste_t pgste_update_all(pte_t *ptep, pgste_t pgste)
static inline pgste_t pgste_update_all(pte_t *ptep, pgste_t pgste,
struct mm_struct *mm)
{
#ifdef CONFIG_PGSTE
unsigned long address, bits, skey;
if (pte_val(*ptep) & _PAGE_INVALID)
if (!mm_use_skey(mm) || pte_val(*ptep) & _PAGE_INVALID)
return pgste;
address = pte_val(*ptep) & PAGE_MASK;
skey = (unsigned long) page_get_storage_key(address);
@ -729,10 +740,11 @@ static inline pgste_t pgste_update_all(pte_t *ptep, pgste_t pgste)
}
static inline pgste_t pgste_update_young(pte_t *ptep, pgste_t pgste)
static inline pgste_t pgste_update_young(pte_t *ptep, pgste_t pgste,
struct mm_struct *mm)
{
#ifdef CONFIG_PGSTE
if (pte_val(*ptep) & _PAGE_INVALID)
if (!mm_use_skey(mm) || pte_val(*ptep) & _PAGE_INVALID)
return pgste;
/* Get referenced bit from storage key */
if (page_reset_referenced(pte_val(*ptep) & PAGE_MASK))
@ -741,13 +753,14 @@ static inline pgste_t pgste_update_young(pte_t *ptep, pgste_t pgste)
return pgste;
}
static inline void pgste_set_key(pte_t *ptep, pgste_t pgste, pte_t entry)
static inline void pgste_set_key(pte_t *ptep, pgste_t pgste, pte_t entry,
struct mm_struct *mm)
{
#ifdef CONFIG_PGSTE
unsigned long address;
unsigned long nkey;
if (pte_val(entry) & _PAGE_INVALID)
if (!mm_use_skey(mm) || pte_val(entry) & _PAGE_INVALID)
return;
VM_BUG_ON(!(pte_val(*ptep) & _PAGE_INVALID));
address = pte_val(entry) & PAGE_MASK;
@ -870,7 +883,7 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
if (mm_has_pgste(mm)) {
pgste = pgste_get_lock(ptep);
pgste_val(pgste) &= ~_PGSTE_GPS_ZERO;
pgste_set_key(ptep, pgste, entry);
pgste_set_key(ptep, pgste, entry, mm);
pgste_set_pte(ptep, entry);
pgste_set_unlock(ptep, pgste);
} else {
@ -1028,7 +1041,7 @@ static inline int ptep_test_and_clear_user_dirty(struct mm_struct *mm,
if (mm_has_pgste(mm)) {
pgste = pgste_get_lock(ptep);
pgste = pgste_update_all(ptep, pgste);
pgste = pgste_update_all(ptep, pgste, mm);
dirty = !!(pgste_val(pgste) & PGSTE_HC_BIT);
pgste_val(pgste) &= ~PGSTE_HC_BIT;
pgste_set_unlock(ptep, pgste);
@ -1048,7 +1061,7 @@ static inline int ptep_test_and_clear_user_young(struct mm_struct *mm,
if (mm_has_pgste(mm)) {
pgste = pgste_get_lock(ptep);
pgste = pgste_update_young(ptep, pgste);
pgste = pgste_update_young(ptep, pgste, mm);
young = !!(pgste_val(pgste) & PGSTE_HR_BIT);
pgste_val(pgste) &= ~PGSTE_HR_BIT;
pgste_set_unlock(ptep, pgste);
@ -1182,7 +1195,7 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
pte_val(*ptep) = _PAGE_INVALID;
if (mm_has_pgste(mm)) {
pgste = pgste_update_all(&pte, pgste);
pgste = pgste_update_all(&pte, pgste, mm);
pgste_set_unlock(ptep, pgste);
}
return pte;
@ -1205,7 +1218,7 @@ static inline pte_t ptep_modify_prot_start(struct mm_struct *mm,
ptep_flush_lazy(mm, address, ptep);
if (mm_has_pgste(mm)) {
pgste = pgste_update_all(&pte, pgste);
pgste = pgste_update_all(&pte, pgste, mm);
pgste_set(ptep, pgste);
}
return pte;
@ -1219,7 +1232,7 @@ static inline void ptep_modify_prot_commit(struct mm_struct *mm,
if (mm_has_pgste(mm)) {
pgste = pgste_get(ptep);
pgste_set_key(ptep, pgste, pte);
pgste_set_key(ptep, pgste, pte, mm);
pgste_set_pte(ptep, pte);
pgste_set_unlock(ptep, pgste);
} else
@ -1246,7 +1259,7 @@ static inline pte_t ptep_clear_flush(struct vm_area_struct *vma,
if ((pgste_val(pgste) & _PGSTE_GPS_USAGE_MASK) ==
_PGSTE_GPS_USAGE_UNUSED)
pte_val(pte) |= _PAGE_UNUSED;
pgste = pgste_update_all(&pte, pgste);
pgste = pgste_update_all(&pte, pgste, vma->vm_mm);
pgste_set_unlock(ptep, pgste);
}
return pte;
@ -1278,7 +1291,7 @@ static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
pte_val(*ptep) = _PAGE_INVALID;
if (!full && mm_has_pgste(mm)) {
pgste = pgste_update_all(&pte, pgste);
pgste = pgste_update_all(&pte, pgste, mm);
pgste_set_unlock(ptep, pgste);
}
return pte;