diff options
Diffstat (limited to 'include/asm-s390/pgtable.h')
| -rw-r--r-- | include/asm-s390/pgtable.h | 50 |
1 files changed, 40 insertions, 10 deletions
diff --git a/include/asm-s390/pgtable.h b/include/asm-s390/pgtable.h index 519f0a5..36bb6da 100644 --- a/include/asm-s390/pgtable.h +++ b/include/asm-s390/pgtable.h @@ -200,18 +200,45 @@ extern char empty_zero_page[PAGE_SIZE]; */ /* Hardware bits in the page table entry */ -#define _PAGE_RO 0x200 /* HW read-only */ -#define _PAGE_INVALID 0x400 /* HW invalid */ +#define _PAGE_RO 0x200 /* HW read-only bit */ +#define _PAGE_INVALID 0x400 /* HW invalid bit */ +#define _PAGE_SWT 0x001 /* SW pte type bit t */ +#define _PAGE_SWX 0x002 /* SW pte type bit x */ -/* Mask and six different types of pages. */ -#define _PAGE_TYPE_MASK 0x601 +/* Six different types of pages. */ #define _PAGE_TYPE_EMPTY 0x400 #define _PAGE_TYPE_NONE 0x401 -#define _PAGE_TYPE_SWAP 0x600 -#define _PAGE_TYPE_FILE 0x601 +#define _PAGE_TYPE_SWAP 0x403 +#define _PAGE_TYPE_FILE 0x601 /* bit 0x002 is used for offset !! */ #define _PAGE_TYPE_RO 0x200 #define _PAGE_TYPE_RW 0x000 +/* + * PTE type bits are rather complicated. handle_pte_fault uses pte_present, + * pte_none and pte_file to find out the pte type WITHOUT holding the page + * table lock. ptep_clear_flush on the other hand uses ptep_clear_flush to + * invalidate a given pte. ipte sets the hw invalid bit and clears all tlbs + * for the page. The page table entry is set to _PAGE_TYPE_EMPTY afterwards. + * This change is done while holding the lock, but the intermediate step + * of a previously valid pte with the hw invalid bit set can be observed by + * handle_pte_fault. That makes it necessary that all valid pte types with + * the hw invalid bit set must be distinguishable from the four pte types + * empty, none, swap and file. + * + * irxt ipte irxt + * _PAGE_TYPE_EMPTY 1000 -> 1000 + * _PAGE_TYPE_NONE 1001 -> 1001 + * _PAGE_TYPE_SWAP 1011 -> 1011 + * _PAGE_TYPE_FILE 11?1 -> 11?1 + * _PAGE_TYPE_RO 0100 -> 1100 + * _PAGE_TYPE_RW 0000 -> 1000 + * + * pte_none is true for bits combinations 1000, 1100 + * pte_present is true for bits combinations 0000, 0010, 0100, 0110, 1001 + * pte_file is true for bits combinations 1101, 1111 + * swap pte is 1011 and 0001, 0011, 0101, 0111, 1010 and 1110 are invalid. + */ + #ifndef __s390x__ /* Bits in the segment table entry */ @@ -365,18 +392,21 @@ static inline int pmd_bad(pmd_t pmd) static inline int pte_none(pte_t pte) { - return (pte_val(pte) & _PAGE_TYPE_MASK) == _PAGE_TYPE_EMPTY; + return (pte_val(pte) & _PAGE_INVALID) && !(pte_val(pte) & _PAGE_SWT); } static inline int pte_present(pte_t pte) { - return !(pte_val(pte) & _PAGE_INVALID) || - (pte_val(pte) & _PAGE_TYPE_MASK) == _PAGE_TYPE_NONE; + unsigned long mask = _PAGE_RO | _PAGE_INVALID | _PAGE_SWT | _PAGE_SWX; + return (pte_val(pte) & mask) == _PAGE_TYPE_NONE || + (!(pte_val(pte) & _PAGE_INVALID) && + !(pte_val(pte) & _PAGE_SWT)); } static inline int pte_file(pte_t pte) { - return (pte_val(pte) & _PAGE_TYPE_MASK) == _PAGE_TYPE_FILE; + unsigned long mask = _PAGE_RO | _PAGE_INVALID | _PAGE_SWT; + return (pte_val(pte) & mask) == _PAGE_TYPE_FILE; } #define pte_same(a,b) (pte_val(a) == pte_val(b)) |