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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2008-02-09 18:24:37 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2008-02-09 18:24:41 +0100
commit6252d702c5311ce916caf75ed82e5c8245171c92 (patch)
tree3490f27b5f888ff2c1ec915d4e7201000f37a771 /include/asm-s390/pgtable.h
parent5a216a20837c5f5fa1ca4b8ae8991ffd96b08e6f (diff)
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[S390] dynamic page tables.
Add support for different number of page table levels dependent on the highest address used for a process. This will cause a 31 bit process to use a two level page table instead of the four level page table that is the default after the pud has been introduced. Likewise a normal 64 bit process will use three levels instead of four. Only if a process runs out of the 4 tera bytes which can be addressed with a three level page table the fourth level is dynamically added. Then the process can use up to 8 peta byte. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'include/asm-s390/pgtable.h')
-rw-r--r--include/asm-s390/pgtable.h38
1 files changed, 31 insertions, 7 deletions
diff --git a/include/asm-s390/pgtable.h b/include/asm-s390/pgtable.h
index 8f473a718111..65154dc9a9e5 100644
--- a/include/asm-s390/pgtable.h
+++ b/include/asm-s390/pgtable.h
@@ -421,36 +421,54 @@ static inline int pud_bad(pud_t pud) { return 0; }
static inline int pgd_present(pgd_t pgd)
{
+ if ((pgd_val(pgd) & _REGION_ENTRY_TYPE_MASK) < _REGION_ENTRY_TYPE_R2)
+ return 1;
return (pgd_val(pgd) & _REGION_ENTRY_ORIGIN) != 0UL;
}
static inline int pgd_none(pgd_t pgd)
{
+ if ((pgd_val(pgd) & _REGION_ENTRY_TYPE_MASK) < _REGION_ENTRY_TYPE_R2)
+ return 0;
return (pgd_val(pgd) & _REGION_ENTRY_INV) != 0UL;
}
static inline int pgd_bad(pgd_t pgd)
{
+ /*
+ * With dynamic page table levels the pgd can be a region table
+ * entry or a segment table entry. Check for the bit that are
+ * invalid for either table entry.
+ */
unsigned long mask =
- ~_REGION_ENTRY_ORIGIN & ~_REGION_ENTRY_INV &
+ ~_SEGMENT_ENTRY_ORIGIN & ~_REGION_ENTRY_INV &
~_REGION_ENTRY_TYPE_MASK & ~_REGION_ENTRY_LENGTH;
return (pgd_val(pgd) & mask) != 0;
}
static inline int pud_present(pud_t pud)
{
+ if ((pud_val(pud) & _REGION_ENTRY_TYPE_MASK) < _REGION_ENTRY_TYPE_R3)
+ return 1;
return (pud_val(pud) & _REGION_ENTRY_ORIGIN) != 0UL;
}
static inline int pud_none(pud_t pud)
{
+ if ((pud_val(pud) & _REGION_ENTRY_TYPE_MASK) < _REGION_ENTRY_TYPE_R3)
+ return 0;
return (pud_val(pud) & _REGION_ENTRY_INV) != 0UL;
}
static inline int pud_bad(pud_t pud)
{
+ /*
+ * With dynamic page table levels the pud can be a region table
+ * entry or a segment table entry. Check for the bit that are
+ * invalid for either table entry.
+ */
unsigned long mask =
- ~_REGION_ENTRY_ORIGIN & ~_REGION_ENTRY_INV &
+ ~_SEGMENT_ENTRY_ORIGIN & ~_REGION_ENTRY_INV &
~_REGION_ENTRY_TYPE_MASK & ~_REGION_ENTRY_LENGTH;
return (pud_val(pud) & mask) != 0;
}
@@ -535,7 +553,8 @@ static inline int pte_young(pte_t pte)
static inline void pgd_clear_kernel(pgd_t * pgd)
{
- pgd_val(*pgd) = _REGION2_ENTRY_EMPTY;
+ if ((pgd_val(*pgd) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R2)
+ pgd_val(*pgd) = _REGION2_ENTRY_EMPTY;
}
static inline void pgd_clear(pgd_t * pgd)
@@ -549,10 +568,11 @@ static inline void pgd_clear(pgd_t * pgd)
static inline void pud_clear_kernel(pud_t *pud)
{
- pud_val(*pud) = _REGION3_ENTRY_EMPTY;
+ if ((pud_val(*pud) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3)
+ pud_val(*pud) = _REGION3_ENTRY_EMPTY;
}
-static inline void pud_clear(pud_t * pud)
+static inline void pud_clear(pud_t *pud)
{
pud_t *shadow = get_shadow_table(pud);
@@ -841,13 +861,17 @@ static inline pte_t mk_pte(struct page *page, pgprot_t pgprot)
static inline pud_t *pud_offset(pgd_t *pgd, unsigned long address)
{
- pud_t *pud = (pud_t *) pgd_deref(*pgd);
+ pud_t *pud = (pud_t *) pgd;
+ if ((pgd_val(*pgd) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R2)
+ pud = (pud_t *) pgd_deref(*pgd);
return pud + pud_index(address);
}
static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address)
{
- pmd_t *pmd = (pmd_t *) pud_deref(*pud);
+ pmd_t *pmd = (pmd_t *) pud;
+ if ((pud_val(*pud) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3)
+ pmd = (pmd_t *) pud_deref(*pud);
return pmd + pmd_index(address);
}