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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2014-07-24 11:03:41 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2014-08-01 14:55:05 +0200
commit152125b7a882df36a55a8eadbea6d0edf1461ee7 (patch)
tree247d93a58d6ff9ff9ccbe66840acaa240069d879 /arch/s390/mm/hugetlbpage.c
parentKVM: s390/mm: Fix page table locking vs. split pmd lock (diff)
downloadlinux-dev-152125b7a882df36a55a8eadbea6d0edf1461ee7.tar.xz
linux-dev-152125b7a882df36a55a8eadbea6d0edf1461ee7.zip
s390/mm: implement dirty bits for large segment table entries
The large segment table entry format has block of bits for the ACC/F values for the large page. These bits are valid only if another bit (AV bit 0x10000) of the segment table entry is set. The ACC/F bits do not have a meaning if the AV bit is off. This allows to put the THP splitting bit, the segment young bit and the new segment dirty bit into the ACC/F bits as long as the AV bit stays off. The dirty and young information is only available if the pmd is large. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/mm/hugetlbpage.c')
-rw-r--r--arch/s390/mm/hugetlbpage.c103
1 files changed, 47 insertions, 56 deletions
diff --git a/arch/s390/mm/hugetlbpage.c b/arch/s390/mm/hugetlbpage.c
index 0ff66a7e29bb..389bc17934b7 100644
--- a/arch/s390/mm/hugetlbpage.c
+++ b/arch/s390/mm/hugetlbpage.c
@@ -10,42 +10,33 @@
static inline pmd_t __pte_to_pmd(pte_t pte)
{
- int none, young, prot;
pmd_t pmd;
/*
- * Convert encoding pte bits pmd bits
- * .IR...wrdytp ..R...I...y.
- * empty .10...000000 -> ..0...1...0.
- * prot-none, clean, old .11...000001 -> ..0...1...1.
- * prot-none, clean, young .11...000101 -> ..1...1...1.
- * prot-none, dirty, old .10...001001 -> ..0...1...1.
- * prot-none, dirty, young .10...001101 -> ..1...1...1.
- * read-only, clean, old .11...010001 -> ..1...1...0.
- * read-only, clean, young .01...010101 -> ..1...0...1.
- * read-only, dirty, old .11...011001 -> ..1...1...0.
- * read-only, dirty, young .01...011101 -> ..1...0...1.
- * read-write, clean, old .11...110001 -> ..0...1...0.
- * read-write, clean, young .01...110101 -> ..0...0...1.
- * read-write, dirty, old .10...111001 -> ..0...1...0.
- * read-write, dirty, young .00...111101 -> ..0...0...1.
- * Huge ptes are dirty by definition, a clean pte is made dirty
- * by the conversion.
+ * Convert encoding pte bits pmd bits
+ * .IR...wrdytp dy..R...I...wr
+ * empty .10...000000 -> 00..0...1...00
+ * prot-none, clean, old .11...000001 -> 00..1...1...00
+ * prot-none, clean, young .11...000101 -> 01..1...1...00
+ * prot-none, dirty, old .10...001001 -> 10..1...1...00
+ * prot-none, dirty, young .10...001101 -> 11..1...1...00
+ * read-only, clean, old .11...010001 -> 00..1...1...01
+ * read-only, clean, young .01...010101 -> 01..1...0...01
+ * read-only, dirty, old .11...011001 -> 10..1...1...01
+ * read-only, dirty, young .01...011101 -> 11..1...0...01
+ * read-write, clean, old .11...110001 -> 00..0...1...11
+ * read-write, clean, young .01...110101 -> 01..0...0...11
+ * read-write, dirty, old .10...111001 -> 10..0...1...11
+ * read-write, dirty, young .00...111101 -> 11..0...0...11
*/
if (pte_present(pte)) {
pmd_val(pmd) = pte_val(pte) & PAGE_MASK;
- if (pte_val(pte) & _PAGE_INVALID)
- pmd_val(pmd) |= _SEGMENT_ENTRY_INVALID;
- none = (pte_val(pte) & _PAGE_PRESENT) &&
- !(pte_val(pte) & _PAGE_READ) &&
- !(pte_val(pte) & _PAGE_WRITE);
- prot = (pte_val(pte) & _PAGE_PROTECT) &&
- !(pte_val(pte) & _PAGE_WRITE);
- young = pte_val(pte) & _PAGE_YOUNG;
- if (none || young)
- pmd_val(pmd) |= _SEGMENT_ENTRY_YOUNG;
- if (prot || (none && young))
- pmd_val(pmd) |= _SEGMENT_ENTRY_PROTECT;
+ pmd_val(pmd) |= (pte_val(pte) & _PAGE_READ) >> 4;
+ pmd_val(pmd) |= (pte_val(pte) & _PAGE_WRITE) >> 4;
+ pmd_val(pmd) |= (pte_val(pte) & _PAGE_INVALID) >> 5;
+ pmd_val(pmd) |= (pte_val(pte) & _PAGE_PROTECT);
+ pmd_val(pmd) |= (pte_val(pte) & _PAGE_DIRTY) << 10;
+ pmd_val(pmd) |= (pte_val(pte) & _PAGE_YOUNG) << 10;
} else
pmd_val(pmd) = _SEGMENT_ENTRY_INVALID;
return pmd;
@@ -56,34 +47,31 @@ static inline pte_t __pmd_to_pte(pmd_t pmd)
pte_t pte;
/*
- * Convert encoding pmd bits pte bits
- * ..R...I...y. .IR...wrdytp
- * empty ..0...1...0. -> .10...000000
- * prot-none, old ..0...1...1. -> .10...001001
- * prot-none, young ..1...1...1. -> .10...001101
- * read-only, old ..1...1...0. -> .11...011001
- * read-only, young ..1...0...1. -> .01...011101
- * read-write, old ..0...1...0. -> .10...111001
- * read-write, young ..0...0...1. -> .00...111101
- * Huge ptes are dirty by definition
+ * Convert encoding pmd bits pte bits
+ * dy..R...I...wr .IR...wrdytp
+ * empty 00..0...1...00 -> .10...001100
+ * prot-none, clean, old 00..0...1...00 -> .10...000001
+ * prot-none, clean, young 01..0...1...00 -> .10...000101
+ * prot-none, dirty, old 10..0...1...00 -> .10...001001
+ * prot-none, dirty, young 11..0...1...00 -> .10...001101
+ * read-only, clean, old 00..1...1...01 -> .11...010001
+ * read-only, clean, young 01..1...1...01 -> .11...010101
+ * read-only, dirty, old 10..1...1...01 -> .11...011001
+ * read-only, dirty, young 11..1...1...01 -> .11...011101
+ * read-write, clean, old 00..0...1...11 -> .10...110001
+ * read-write, clean, young 01..0...1...11 -> .10...110101
+ * read-write, dirty, old 10..0...1...11 -> .10...111001
+ * read-write, dirty, young 11..0...1...11 -> .10...111101
*/
if (pmd_present(pmd)) {
- pte_val(pte) = _PAGE_PRESENT | _PAGE_LARGE | _PAGE_DIRTY |
- (pmd_val(pmd) & PAGE_MASK);
- if (pmd_val(pmd) & _SEGMENT_ENTRY_INVALID)
- pte_val(pte) |= _PAGE_INVALID;
- if (pmd_prot_none(pmd)) {
- if (pmd_val(pmd) & _SEGMENT_ENTRY_PROTECT)
- pte_val(pte) |= _PAGE_YOUNG;
- } else {
- pte_val(pte) |= _PAGE_READ;
- if (pmd_val(pmd) & _SEGMENT_ENTRY_PROTECT)
- pte_val(pte) |= _PAGE_PROTECT;
- else
- pte_val(pte) |= _PAGE_WRITE;
- if (pmd_val(pmd) & _SEGMENT_ENTRY_YOUNG)
- pte_val(pte) |= _PAGE_YOUNG;
- }
+ pte_val(pte) = pmd_val(pmd) & _SEGMENT_ENTRY_ORIGIN_LARGE;
+ pte_val(pte) |= _PAGE_LARGE | _PAGE_PRESENT;
+ pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_READ) << 4;
+ pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_WRITE) << 4;
+ pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_INVALID) << 5;
+ pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_PROTECT);
+ pmd_val(pmd) |= (pte_val(pte) & _PAGE_DIRTY) << 10;
+ pmd_val(pmd) |= (pte_val(pte) & _PAGE_YOUNG) << 10;
} else
pte_val(pte) = _PAGE_INVALID;
return pte;
@@ -96,6 +84,7 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
pmd = __pte_to_pmd(pte);
if (!MACHINE_HAS_HPAGE) {
+ /* Emulated huge ptes loose the dirty and young bit */
pmd_val(pmd) &= ~_SEGMENT_ENTRY_ORIGIN;
pmd_val(pmd) |= pte_page(pte)[1].index;
} else
@@ -113,6 +102,8 @@ pte_t huge_ptep_get(pte_t *ptep)
origin = pmd_val(pmd) & _SEGMENT_ENTRY_ORIGIN;
pmd_val(pmd) &= ~_SEGMENT_ENTRY_ORIGIN;
pmd_val(pmd) |= *(unsigned long *) origin;
+ /* Emulated huge ptes are young and dirty by definition */
+ pmd_val(pmd) |= _SEGMENT_ENTRY_YOUNG | _SEGMENT_ENTRY_DIRTY;
}
return __pmd_to_pte(pmd);
}