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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>
This commit is contained in:
Martin Schwidefsky
parent
b7d14f3a92
commit
a1c843b825
@ -12,12 +12,9 @@
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#define _ASM_S390_PGTABLE_H
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/*
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* The Linux memory management assumes a three-level page table setup. For
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* s390 31 bit we "fold" the mid level into the top-level page table, so
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* that we physically have the same two-level page table as the s390 mmu
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* expects in 31 bit mode. For s390 64 bit we use three of the five levels
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* the hardware provides (region first and region second tables are not
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* used).
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* The Linux memory management assumes a three-level page table setup.
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* For s390 64 bit we use up to four of the five levels the hardware
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* provides (region first tables are not used).
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*
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* The "pgd_xxx()" functions are trivial for a folded two-level
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* setup: the pgd is never bad, and a pmd always exists (as it's folded
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@ -101,8 +98,8 @@ extern unsigned long zero_page_mask;
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#ifndef __ASSEMBLY__
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/*
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* The vmalloc and module area will always be on the topmost area of the kernel
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* mapping. We reserve 96MB (31bit) / 128GB (64bit) for vmalloc and modules.
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* The vmalloc and module area will always be on the topmost area of the
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* kernel mapping. We reserve 128GB (64bit) for vmalloc and modules.
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* On 64 bit kernels we have a 2GB area at the top of the vmalloc area where
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* modules will reside. That makes sure that inter module branches always
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* happen without trampolines and in addition the placement within a 2GB frame
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@ -131,38 +128,6 @@ static inline int is_module_addr(void *addr)
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}
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/*
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* A 31 bit pagetable entry of S390 has following format:
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* | PFRA | | OS |
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* 0 0IP0
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* 00000000001111111111222222222233
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* 01234567890123456789012345678901
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*
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* I Page-Invalid Bit: Page is not available for address-translation
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* P Page-Protection Bit: Store access not possible for page
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*
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* A 31 bit segmenttable entry of S390 has following format:
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* | P-table origin | |PTL
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* 0 IC
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* 00000000001111111111222222222233
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* 01234567890123456789012345678901
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*
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* I Segment-Invalid Bit: Segment is not available for address-translation
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* C Common-Segment Bit: Segment is not private (PoP 3-30)
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* PTL Page-Table-Length: Page-table length (PTL+1*16 entries -> up to 256)
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*
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* The 31 bit segmenttable origin of S390 has following format:
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*
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* |S-table origin | | STL |
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* X **GPS
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* 00000000001111111111222222222233
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* 01234567890123456789012345678901
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*
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* X Space-Switch event:
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* G Segment-Invalid Bit: *
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* P Private-Space Bit: Segment is not private (PoP 3-30)
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* S Storage-Alteration:
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* STL Segment-Table-Length: Segment-table length (STL+1*16 entries -> up to 2048)
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*
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* A 64 bit pagetable entry of S390 has following format:
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* | PFRA |0IPC| OS |
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* 0000000000111111111122222222223333333333444444444455555555556666
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@ -220,7 +185,6 @@ static inline int is_module_addr(void *addr)
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/* Software bits in the page table entry */
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#define _PAGE_PRESENT 0x001 /* SW pte present bit */
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#define _PAGE_TYPE 0x002 /* SW pte type bit */
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#define _PAGE_YOUNG 0x004 /* SW pte young bit */
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#define _PAGE_DIRTY 0x008 /* SW pte dirty bit */
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#define _PAGE_READ 0x010 /* SW pte read bit */
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@ -240,31 +204,34 @@ static inline int is_module_addr(void *addr)
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* table lock held.
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*
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* The following table gives the different possible bit combinations for
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* the pte hardware and software bits in the last 12 bits of a pte:
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* the pte hardware and software bits in the last 12 bits of a pte
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* (. unassigned bit, x don't care, t swap type):
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*
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* 842100000000
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* 000084210000
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* 000000008421
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* .IR...wrdytp
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* empty .10...000000
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* swap .10...xxxx10
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* file .11...xxxxx0
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* prot-none, clean, old .11...000001
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* prot-none, clean, young .11...000101
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* prot-none, dirty, old .10...001001
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* prot-none, dirty, young .10...001101
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* read-only, clean, old .11...010001
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* read-only, clean, young .01...010101
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* read-only, dirty, old .11...011001
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* read-only, dirty, young .01...011101
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* read-write, clean, old .11...110001
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* read-write, clean, young .01...110101
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* read-write, dirty, old .10...111001
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* read-write, dirty, young .00...111101
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* .IR.uswrdy.p
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* empty .10.00000000
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* swap .11..ttttt.0
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* prot-none, clean, old .11.xx0000.1
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* prot-none, clean, young .11.xx0001.1
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* prot-none, dirty, old .10.xx0010.1
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* prot-none, dirty, young .10.xx0011.1
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* read-only, clean, old .11.xx0100.1
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* read-only, clean, young .01.xx0101.1
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* read-only, dirty, old .11.xx0110.1
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* read-only, dirty, young .01.xx0111.1
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* read-write, clean, old .11.xx1100.1
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* read-write, clean, young .01.xx1101.1
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* read-write, dirty, old .10.xx1110.1
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* read-write, dirty, young .00.xx1111.1
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* HW-bits: R read-only, I invalid
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* SW-bits: p present, y young, d dirty, r read, w write, s special,
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* u unused, l large
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*
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* pte_present is true for the bit pattern .xx...xxxxx1, (pte & 0x001) == 0x001
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* pte_none is true for the bit pattern .10...xxxx00, (pte & 0x603) == 0x400
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* pte_swap is true for the bit pattern .10...xxxx10, (pte & 0x603) == 0x402
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* pte_none is true for the bit pattern .10.00000000, pte == 0x400
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* pte_swap is true for the bit pattern .11..ooooo.0, (pte & 0x201) == 0x200
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* pte_present is true for the bit pattern .xx.xxxxxx.1, (pte & 0x001) == 0x001
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*/
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/* Bits in the segment/region table address-space-control-element */
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@ -335,6 +302,8 @@ static inline int is_module_addr(void *addr)
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* read-write, dirty, young 11..0...0...11
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* The segment table origin is used to distinguish empty (origin==0) from
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* read-write, old segment table entries (origin!=0)
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* HW-bits: R read-only, I invalid
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* SW-bits: y young, d dirty, r read, w write
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*/
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#define _SEGMENT_ENTRY_SPLIT_BIT 11 /* THP splitting bit number */
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@ -591,10 +560,9 @@ static inline int pte_none(pte_t pte)
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static inline int pte_swap(pte_t pte)
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{
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/* Bit pattern: (pte & 0x603) == 0x402 */
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return (pte_val(pte) & (_PAGE_INVALID | _PAGE_PROTECT |
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_PAGE_TYPE | _PAGE_PRESENT))
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== (_PAGE_INVALID | _PAGE_TYPE);
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/* Bit pattern: (pte & 0x201) == 0x200 */
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return (pte_val(pte) & (_PAGE_PROTECT | _PAGE_PRESENT))
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== _PAGE_PROTECT;
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}
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static inline int pte_special(pte_t pte)
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@ -1595,51 +1563,51 @@ static inline int has_transparent_hugepage(void)
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#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
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/*
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* 31 bit swap entry format:
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* A page-table entry has some bits we have to treat in a special way.
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* Bits 0, 20 and bit 23 have to be zero, otherwise an specification
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* exception will occur instead of a page translation exception. The
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* specifiation exception has the bad habit not to store necessary
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* information in the lowcore.
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* Bits 21, 22, 30 and 31 are used to indicate the page type.
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* A swap pte is indicated by bit pattern (pte & 0x603) == 0x402
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* This leaves the bits 1-19 and bits 24-29 to store type and offset.
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* We use the 5 bits from 25-29 for the type and the 20 bits from 1-19
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* plus 24 for the offset.
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* 0| offset |0110|o|type |00|
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* 0 0000000001111111111 2222 2 22222 33
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* 0 1234567890123456789 0123 4 56789 01
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*
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* 64 bit swap entry format:
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* A page-table entry has some bits we have to treat in a special way.
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* Bits 52 and bit 55 have to be zero, otherwise an specification
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* exception will occur instead of a page translation exception. The
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* specifiation exception has the bad habit not to store necessary
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* information in the lowcore.
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* Bits 53, 54, 62 and 63 are used to indicate the page type.
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* A swap pte is indicated by bit pattern (pte & 0x603) == 0x402
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* This leaves the bits 0-51 and bits 56-61 to store type and offset.
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* We use the 5 bits from 57-61 for the type and the 53 bits from 0-51
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* plus 56 for the offset.
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* | offset |0110|o|type |00|
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* 0000000000111111111122222222223333333333444444444455 5555 5 55566 66
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* 0123456789012345678901234567890123456789012345678901 2345 6 78901 23
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* Bits 54 and 63 are used to indicate the page type.
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* A swap pte is indicated by bit pattern (pte & 0x201) == 0x200
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* This leaves the bits 0-51 and bits 56-62 to store type and offset.
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* We use the 5 bits from 57-61 for the type and the 52 bits from 0-51
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* for the offset.
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* | offset |01100|type |00|
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* |0000000000111111111122222222223333333333444444444455|55555|55566|66|
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* |0123456789012345678901234567890123456789012345678901|23456|78901|23|
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*/
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#define __SWP_OFFSET_MASK (~0UL >> 11)
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#define __SWP_OFFSET_MASK ((1UL << 52) - 1)
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#define __SWP_OFFSET_SHIFT 12
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#define __SWP_TYPE_MASK ((1UL << 5) - 1)
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#define __SWP_TYPE_SHIFT 2
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static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
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{
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pte_t pte;
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offset &= __SWP_OFFSET_MASK;
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pte_val(pte) = _PAGE_INVALID | _PAGE_TYPE | ((type & 0x1f) << 2) |
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((offset & 1UL) << 7) | ((offset & ~1UL) << 11);
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pte_val(pte) = _PAGE_INVALID | _PAGE_PROTECT;
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pte_val(pte) |= (offset & __SWP_OFFSET_MASK) << __SWP_OFFSET_SHIFT;
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pte_val(pte) |= (type & __SWP_TYPE_MASK) << __SWP_TYPE_SHIFT;
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return pte;
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}
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#define __swp_type(entry) (((entry).val >> 2) & 0x1f)
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#define __swp_offset(entry) (((entry).val >> 11) | (((entry).val >> 7) & 1))
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#define __swp_entry(type,offset) ((swp_entry_t) { pte_val(mk_swap_pte((type),(offset))) })
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static inline unsigned long __swp_type(swp_entry_t entry)
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{
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return (entry.val >> __SWP_TYPE_SHIFT) & __SWP_TYPE_MASK;
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}
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static inline unsigned long __swp_offset(swp_entry_t entry)
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{
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return (entry.val >> __SWP_OFFSET_SHIFT) & __SWP_OFFSET_MASK;
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}
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static inline swp_entry_t __swp_entry(unsigned long type, unsigned long offset)
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{
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return (swp_entry_t) { pte_val(mk_swap_pte(type, offset)) };
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}
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#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
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#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
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@ -14,20 +14,23 @@ static inline pmd_t __pte_to_pmd(pte_t pte)
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/*
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* Convert encoding pte bits pmd bits
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* .IR...wrdytp dy..R...I...wr
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* empty .10...000000 -> 00..0...1...00
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* prot-none, clean, old .11...000001 -> 00..1...1...00
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* prot-none, clean, young .11...000101 -> 01..1...1...00
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* prot-none, dirty, old .10...001001 -> 10..1...1...00
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* prot-none, dirty, young .10...001101 -> 11..1...1...00
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* read-only, clean, old .11...010001 -> 00..1...1...01
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* read-only, clean, young .01...010101 -> 01..1...0...01
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* read-only, dirty, old .11...011001 -> 10..1...1...01
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* read-only, dirty, young .01...011101 -> 11..1...0...01
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* read-write, clean, old .11...110001 -> 00..0...1...11
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* read-write, clean, young .01...110101 -> 01..0...0...11
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* read-write, dirty, old .10...111001 -> 10..0...1...11
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* read-write, dirty, young .00...111101 -> 11..0...0...11
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* lIR.uswrdy.p dy..R...I...wr
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* empty 010.000000.0 -> 00..0...1...00
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* prot-none, clean, old 111.000000.1 -> 00..1...1...00
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* prot-none, clean, young 111.000001.1 -> 01..1...1...00
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* prot-none, dirty, old 111.000010.1 -> 10..1...1...00
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* prot-none, dirty, young 111.000011.1 -> 11..1...1...00
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* read-only, clean, old 111.000100.1 -> 00..1...1...01
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* read-only, clean, young 101.000101.1 -> 01..1...0...01
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* read-only, dirty, old 111.000110.1 -> 10..1...1...01
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* read-only, dirty, young 101.000111.1 -> 11..1...0...01
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* read-write, clean, old 111.001100.1 -> 00..1...1...11
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* read-write, clean, young 101.001101.1 -> 01..1...0...11
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* read-write, dirty, old 110.001110.1 -> 10..0...1...11
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* read-write, dirty, young 100.001111.1 -> 11..0...0...11
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* HW-bits: R read-only, I invalid
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* SW-bits: p present, y young, d dirty, r read, w write, s special,
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* u unused, l large
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*/
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if (pte_present(pte)) {
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pmd_val(pmd) = pte_val(pte) & PAGE_MASK;
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@ -48,20 +51,23 @@ static inline pte_t __pmd_to_pte(pmd_t pmd)
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/*
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* Convert encoding pmd bits pte bits
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* dy..R...I...wr .IR...wrdytp
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* empty 00..0...1...00 -> .10...001100
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* prot-none, clean, old 00..0...1...00 -> .10...000001
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* prot-none, clean, young 01..0...1...00 -> .10...000101
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* prot-none, dirty, old 10..0...1...00 -> .10...001001
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* prot-none, dirty, young 11..0...1...00 -> .10...001101
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* read-only, clean, old 00..1...1...01 -> .11...010001
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* read-only, clean, young 01..1...1...01 -> .11...010101
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* read-only, dirty, old 10..1...1...01 -> .11...011001
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* read-only, dirty, young 11..1...1...01 -> .11...011101
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* read-write, clean, old 00..0...1...11 -> .10...110001
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* read-write, clean, young 01..0...1...11 -> .10...110101
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* read-write, dirty, old 10..0...1...11 -> .10...111001
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* read-write, dirty, young 11..0...1...11 -> .10...111101
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* dy..R...I...wr lIR.uswrdy.p
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* empty 00..0...1...00 -> 010.000000.0
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* prot-none, clean, old 00..1...1...00 -> 111.000000.1
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* prot-none, clean, young 01..1...1...00 -> 111.000001.1
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* prot-none, dirty, old 10..1...1...00 -> 111.000010.1
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* prot-none, dirty, young 11..1...1...00 -> 111.000011.1
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* read-only, clean, old 00..1...1...01 -> 111.000100.1
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* read-only, clean, young 01..1...0...01 -> 101.000101.1
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* read-only, dirty, old 10..1...1...01 -> 111.000110.1
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* read-only, dirty, young 11..1...0...01 -> 101.000111.1
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* read-write, clean, old 00..1...1...11 -> 111.001100.1
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* read-write, clean, young 01..1...0...11 -> 101.001101.1
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* read-write, dirty, old 10..0...1...11 -> 110.001110.1
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* read-write, dirty, young 11..0...0...11 -> 100.001111.1
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* HW-bits: R read-only, I invalid
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* SW-bits: p present, y young, d dirty, r read, w write, s special,
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* u unused, l large
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*/
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if (pmd_present(pmd)) {
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pte_val(pte) = pmd_val(pmd) & _SEGMENT_ENTRY_ORIGIN_LARGE;
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