s390/mm: change swap pte encoding and pgtable cleanup

After the file ptes have been removed the bit combination used to
encode non-linear mappings can be reused for the swap ptes. This
frees up a precious pte software bit. Reflect the change in the
swap encoding in the comments and do some cleanup while we are
at it.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 34 insertions, 28 deletions

diff --git a/arch/s390/mm/hugetlbpage.c b/arch/s390/mm/hugetlbpage.c
index c67e8bf012b6..e617e74b7be2 100644
--- a/arch/s390/mm/hugetlbpage.c
+++ b/arch/s390/mm/hugetlbpage.c
@@ -14,20 +14,23 @@ static inline pmd_t __pte_to_pmd(pte_t pte)
 
 	/*
 	 * 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
+	 *				lIR.uswrdy.p	dy..R...I...wr
+	 * empty			010.000000.0 -> 00..0...1...00
+	 * prot-none, clean, old	111.000000.1 -> 00..1...1...00
+	 * prot-none, clean, young	111.000001.1 -> 01..1...1...00
+	 * prot-none, dirty, old	111.000010.1 -> 10..1...1...00
+	 * prot-none, dirty, young	111.000011.1 -> 11..1...1...00
+	 * read-only, clean, old	111.000100.1 -> 00..1...1...01
+	 * read-only, clean, young	101.000101.1 -> 01..1...0...01
+	 * read-only, dirty, old	111.000110.1 -> 10..1...1...01
+	 * read-only, dirty, young	101.000111.1 -> 11..1...0...01
+	 * read-write, clean, old	111.001100.1 -> 00..1...1...11
+	 * read-write, clean, young	101.001101.1 -> 01..1...0...11
+	 * read-write, dirty, old	110.001110.1 -> 10..0...1...11
+	 * read-write, dirty, young	100.001111.1 -> 11..0...0...11
+	 * HW-bits: R read-only, I invalid
+	 * SW-bits: p present, y young, d dirty, r read, w write, s special,
+	 *	    u unused, l large
 	 */
 	if (pte_present(pte)) {
 		pmd_val(pmd) = pte_val(pte) & PAGE_MASK;
@@ -48,20 +51,23 @@ static inline pte_t __pmd_to_pte(pmd_t pmd)
 
 	/*
 	 * 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
+	 *				dy..R...I...wr	  lIR.uswrdy.p
+	 * empty			00..0...1...00 -> 010.000000.0
+	 * prot-none, clean, old	00..1...1...00 -> 111.000000.1
+	 * prot-none, clean, young	01..1...1...00 -> 111.000001.1
+	 * prot-none, dirty, old	10..1...1...00 -> 111.000010.1
+	 * prot-none, dirty, young	11..1...1...00 -> 111.000011.1
+	 * read-only, clean, old	00..1...1...01 -> 111.000100.1
+	 * read-only, clean, young	01..1...0...01 -> 101.000101.1
+	 * read-only, dirty, old	10..1...1...01 -> 111.000110.1
+	 * read-only, dirty, young	11..1...0...01 -> 101.000111.1
+	 * read-write, clean, old	00..1...1...11 -> 111.001100.1
+	 * read-write, clean, young	01..1...0...11 -> 101.001101.1
+	 * read-write, dirty, old	10..0...1...11 -> 110.001110.1
+	 * read-write, dirty, young	11..0...0...11 -> 100.001111.1
+	 * HW-bits: R read-only, I invalid
+	 * SW-bits: p present, y young, d dirty, r read, w write, s special,
+	 *	    u unused, l large
 	 */
 	if (pmd_present(pmd)) {
 		pte_val(pte) = pmd_val(pmd) & _SEGMENT_ENTRY_ORIGIN_LARGE;