[S390] Cleanup page table definitions.

- De-confuse the defines for the address-space-control-elements
  and the segment/region table entries.
- Create out of line functions for page table allocation / freeing.
- Simplify get_shadow_xxx functions.

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

1 files changed, 96 insertions, 123 deletions

diff --git a/include/asm-s390/pgtable.h b/include/asm-s390/pgtable.h
index b424ab21f8bd..f9f59a805e5d 100644
--- a/include/asm-s390/pgtable.h
+++ b/include/asm-s390/pgtable.h
@@ -35,9 +35,6 @@
 #include <asm/bug.h>
 #include <asm/processor.h>
 
-struct vm_area_struct; /* forward declaration (include/linux/mm.h) */
-struct mm_struct;
-
 extern pgd_t swapper_pg_dir[] __attribute__ ((aligned (4096)));
 extern void paging_init(void);
 extern void vmem_map_init(void);
@@ -221,6 +218,8 @@ extern unsigned long vmalloc_end;
 /* Hardware bits in the page table entry */
 #define _PAGE_RO        0x200           /* HW read-only bit  */
 #define _PAGE_INVALID   0x400           /* HW invalid bit    */
+
+/* Software bits in the page table entry */
 #define _PAGE_SWT       0x001           /* SW pte type bit t */
 #define _PAGE_SWX       0x002           /* SW pte type bit x */
 
@@ -264,60 +263,75 @@ extern unsigned long vmalloc_end;
 
 #ifndef __s390x__
 
-/* Bits in the segment table entry */
-#define _PAGE_TABLE_LEN 0xf            /* only full page-tables            */
-#define _PAGE_TABLE_COM 0x10           /* common page-table                */
-#define _PAGE_TABLE_INV 0x20           /* invalid page-table               */
-#define _SEG_PRESENT    0x001          /* Software (overlap with PTL)      */
-
-/* Bits int the storage key */
-#define _PAGE_CHANGED    0x02          /* HW changed bit                   */
-#define _PAGE_REFERENCED 0x04          /* HW referenced bit                */
-
-#define _USER_SEG_TABLE_LEN    0x7f    /* user-segment-table up to 2 GB    */
-#define _KERNEL_SEG_TABLE_LEN  0x7f    /* kernel-segment-table up to 2 GB  */
-
-/*
- * User and Kernel pagetables are identical
- */
-#define _PAGE_TABLE     _PAGE_TABLE_LEN
-#define _KERNPG_TABLE   _PAGE_TABLE_LEN
-
-/*
- * The Kernel segment-tables includes the User segment-table
- */
+/* Bits in the segment table address-space-control-element */
+#define _ASCE_SPACE_SWITCH      0x80000000UL    /* space switch event       */
+#define _ASCE_ORIGIN_MASK       0x7ffff000UL    /* segment table origin     */
+#define _ASCE_PRIVATE_SPACE     0x100   /* private space control            */
+#define _ASCE_ALT_EVENT         0x80    /* storage alteration event control */
+#define _ASCE_TABLE_LENGTH      0x7f    /* 128 x 64 entries = 8k            */
 
-#define _SEGMENT_TABLE  (_USER_SEG_TABLE_LEN|0x80000000|0x100)
-#define _KERNSEG_TABLE  _KERNEL_SEG_TABLE_LEN
+/* Bits in the segment table entry */
+#define _SEGMENT_ENTRY_ORIGIN   0x7fffffc0UL    /* page table origin        */
+#define _SEGMENT_ENTRY_INV      0x20    /* invalid segment table entry      */
+#define _SEGMENT_ENTRY_COMMON   0x10    /* common segment bit               */
+#define _SEGMENT_ENTRY_PTL      0x0f    /* page table length                */
 
-#define USER_STD_MASK   0x00000080UL
+#define _SEGMENT_ENTRY          (_SEGMENT_ENTRY_PTL)
+#define _SEGMENT_ENTRY_EMPTY    (_SEGMENT_ENTRY_INV)
 
 #else /* __s390x__ */
 
+/* Bits in the segment/region table address-space-control-element */
+#define _ASCE_ORIGIN            ~0xfffUL/* segment table origin             */
+#define _ASCE_PRIVATE_SPACE     0x100   /* private space control            */
+#define _ASCE_ALT_EVENT         0x80    /* storage alteration event control */
+#define _ASCE_SPACE_SWITCH      0x40    /* space switch event               */
+#define _ASCE_REAL_SPACE        0x20    /* real space control               */
+#define _ASCE_TYPE_MASK         0x0c    /* asce table type mask             */
+#define _ASCE_TYPE_REGION1      0x0c    /* region first table type          */
+#define _ASCE_TYPE_REGION2      0x08    /* region second table type         */
+#define _ASCE_TYPE_REGION3      0x04    /* region third table type          */
+#define _ASCE_TYPE_SEGMENT      0x00    /* segment table type               */
+#define _ASCE_TABLE_LENGTH      0x03    /* region table length              */
+
+/* Bits in the region table entry */
+#define _REGION_ENTRY_ORIGIN    ~0xfffUL/* region/segment table origin      */
+#define _REGION_ENTRY_INV       0x20    /* invalid region table entry       */
+#define _REGION_ENTRY_TYPE_MASK 0x0c    /* region/segment table type mask   */
+#define _REGION_ENTRY_TYPE_R1   0x0c    /* region first table type          */
+#define _REGION_ENTRY_TYPE_R2   0x08    /* region second table type         */
+#define _REGION_ENTRY_TYPE_R3   0x04    /* region third table type          */
+#define _REGION_ENTRY_LENGTH    0x03    /* region third length              */
+
+#define _REGION1_ENTRY          (_REGION_ENTRY_TYPE_R1 | _REGION_ENTRY_LENGTH)
+#define _REGION1_ENTRY_EMPTY    (_REGION_ENTRY_TYPE_R1 | _REGION_ENTRY_INV)
+#define _REGION2_ENTRY          (_REGION_ENTRY_TYPE_R2 | _REGION_ENTRY_LENGTH)
+#define _REGION2_ENTRY_EMPTY    (_REGION_ENTRY_TYPE_R2 | _REGION_ENTRY_INV)
+#define _REGION3_ENTRY          (_REGION_ENTRY_TYPE_R3 | _REGION_ENTRY_LENGTH)
+#define _REGION3_ENTRY_EMPTY    (_REGION_ENTRY_TYPE_R3 | _REGION_ENTRY_INV)
+
 /* Bits in the segment table entry */
-#define _PMD_ENTRY_INV   0x20          /* invalid segment table entry      */
-#define _PMD_ENTRY       0x00        
+#define _SEGMENT_ENTRY_ORIGIN   ~0x7ffUL/* segment table origin             */
+#define _SEGMENT_ENTRY_RO       0x200   /* page protection bit              */
+#define _SEGMENT_ENTRY_INV      0x20    /* invalid segment table entry      */
 
-/* Bits in the region third table entry */
-#define _PGD_ENTRY_INV   0x20          /* invalid region table entry       */
-#define _PGD_ENTRY       0x07
+#define _SEGMENT_ENTRY          (0)
+#define _SEGMENT_ENTRY_EMPTY    (_SEGMENT_ENTRY_INV)
+
+#endif /* __s390x__ */
 
 /*
- * User and kernel page directory
+ * A user page table pointer has the space-switch-event bit, the
+ * private-space-control bit and the storage-alteration-event-control
+ * bit set. A kernel page table pointer doesn't need them.
  */
-#define _REGION_THIRD       0x4
-#define _REGION_THIRD_LEN   0x3 
-#define _REGION_TABLE       (_REGION_THIRD|_REGION_THIRD_LEN|0x40|0x100)
-#define _KERN_REGION_TABLE  (_REGION_THIRD|_REGION_THIRD_LEN)
-
-#define USER_STD_MASK           0x0000000000000080UL
+#define _ASCE_USER_BITS         (_ASCE_SPACE_SWITCH | _ASCE_PRIVATE_SPACE | \
+                                 _ASCE_ALT_EVENT)
 
-/* Bits in the storage key */
+/* Bits int the storage key */
 #define _PAGE_CHANGED    0x02          /* HW changed bit                   */
 #define _PAGE_REFERENCED 0x04          /* HW referenced bit                */
 
-#endif /* __s390x__ */
-
 /*
  * Page protection definitions.
  */
@@ -358,65 +372,38 @@ extern unsigned long vmalloc_end;
 #define __S111  PAGE_EX_RW
 
 #ifndef __s390x__
-# define PMD_SHADOW_SHIFT       1
-# define PGD_SHADOW_SHIFT       1
+# define PxD_SHADOW_SHIFT       1
 #else /* __s390x__ */
-# define PMD_SHADOW_SHIFT       2
-# define PGD_SHADOW_SHIFT       2
+# define PxD_SHADOW_SHIFT       2
 #endif /* __s390x__ */
 
 static inline struct page *get_shadow_page(struct page *page)
 {
-        if (s390_noexec && !list_empty(&page->lru))
-                return virt_to_page(page->lru.next);
-        return NULL;
-}
-
-static inline pte_t *get_shadow_pte(pte_t *ptep)
-{
-        unsigned long pteptr = (unsigned long) (ptep);
-
-        if (s390_noexec) {
-                unsigned long offset = pteptr & (PAGE_SIZE - 1);
-                void *addr = (void *) (pteptr ^ offset);
-                struct page *page = virt_to_page(addr);
-                if (!list_empty(&page->lru))
-                        return (pte_t *) ((unsigned long) page->lru.next |
-                                                                offset);
-        }
+        if (s390_noexec && page->index)
+                return virt_to_page((void *)(addr_t) page->index);
         return NULL;
 }
 
-static inline pmd_t *get_shadow_pmd(pmd_t *pmdp)
+static inline void *get_shadow_pte(void *table)
 {
-        unsigned long pmdptr = (unsigned long) (pmdp);
+        unsigned long addr, offset;
+        struct page *page;
 
-        if (s390_noexec) {
-                unsigned long offset = pmdptr &
-                                ((PAGE_SIZE << PMD_SHADOW_SHIFT) - 1);
-                void *addr = (void *) (pmdptr ^ offset);
-                struct page *page = virt_to_page(addr);
-                if (!list_empty(&page->lru))
-                        return (pmd_t *) ((unsigned long) page->lru.next |
-                                                                offset);
-        }
-        return NULL;
+        addr = (unsigned long) table;
+        offset = addr & (PAGE_SIZE - 1);
+        page = virt_to_page((void *)(addr ^ offset));
+        return (void *)(addr_t)(page->index ? (page->index | offset) : 0UL);
 }
 
-static inline pgd_t *get_shadow_pgd(pgd_t *pgdp)
+static inline void *get_shadow_table(void *table)
 {
-        unsigned long pgdptr = (unsigned long) (pgdp);
+        unsigned long addr, offset;
+        struct page *page;
 
-        if (s390_noexec) {
-                unsigned long offset = pgdptr &
-                                ((PAGE_SIZE << PGD_SHADOW_SHIFT) - 1);
-                void *addr = (void *) (pgdptr ^ offset);
-                struct page *page = virt_to_page(addr);
-                if (!list_empty(&page->lru))
-                        return (pgd_t *) ((unsigned long) page->lru.next |
-                                                                offset);
-        }
-        return NULL;
+        addr = (unsigned long) table;
+        offset = addr & ((PAGE_SIZE << PxD_SHADOW_SHIFT) - 1);
+        page = virt_to_page((void *)(addr ^ offset));
+        return (void *)(addr_t)(page->index ? (page->index | offset) : 0UL);
 }
 
 /*
@@ -448,47 +435,42 @@ static inline int pgd_present(pgd_t pgd) { return 1; }
 static inline int pgd_none(pgd_t pgd)    { return 0; }
 static inline int pgd_bad(pgd_t pgd)     { return 0; }
 
-static inline int pmd_present(pmd_t pmd) { return pmd_val(pmd) & _SEG_PRESENT; }
-static inline int pmd_none(pmd_t pmd)    { return pmd_val(pmd) & _PAGE_TABLE_INV; }
-static inline int pmd_bad(pmd_t pmd)
-{
-        return (pmd_val(pmd) & (~PAGE_MASK & ~_PAGE_TABLE_INV)) != _PAGE_TABLE;
-}
-
 #else /* __s390x__ */
 
 static inline int pgd_present(pgd_t pgd)
 {
-        return (pgd_val(pgd) & ~PAGE_MASK) == _PGD_ENTRY;
+        return pgd_val(pgd) & _REGION_ENTRY_ORIGIN;
 }
 
 static inline int pgd_none(pgd_t pgd)
 {
-        return pgd_val(pgd) & _PGD_ENTRY_INV;
+        return pgd_val(pgd) & _REGION_ENTRY_INV;
 }
 
 static inline int pgd_bad(pgd_t pgd)
 {
-        return (pgd_val(pgd) & (~PAGE_MASK & ~_PGD_ENTRY_INV)) != _PGD_ENTRY;
+        unsigned long mask = ~_REGION_ENTRY_ORIGIN & ~_REGION_ENTRY_INV;
+        return (pgd_val(pgd) & mask) != _REGION3_ENTRY;
 }
 
+#endif /* __s390x__ */
+
 static inline int pmd_present(pmd_t pmd)
 {
-        return (pmd_val(pmd) & ~PAGE_MASK) == _PMD_ENTRY;
+        return pmd_val(pmd) & _SEGMENT_ENTRY_ORIGIN;
 }
 
 static inline int pmd_none(pmd_t pmd)
 {
-        return pmd_val(pmd) & _PMD_ENTRY_INV;
+        return pmd_val(pmd) & _SEGMENT_ENTRY_INV;
 }
 
 static inline int pmd_bad(pmd_t pmd)
 {
-        return (pmd_val(pmd) & (~PAGE_MASK & ~_PMD_ENTRY_INV)) != _PMD_ENTRY;
+        unsigned long mask = ~_SEGMENT_ENTRY_ORIGIN & ~_SEGMENT_ENTRY_INV;
+        return (pmd_val(pmd) & mask) != _SEGMENT_ENTRY;
 }
 
-#endif /* __s390x__ */
-
 static inline int pte_none(pte_t pte)
 {
         return (pte_val(pte) & _PAGE_INVALID) && !(pte_val(pte) & _PAGE_SWT);
@@ -548,31 +530,22 @@ static inline void pgd_clear(pgd_t * pgdp)      { }
 
 static inline void pmd_clear_kernel(pmd_t * pmdp)
 {
-        pmd_val(pmdp[0]) = _PAGE_TABLE_INV;
-        pmd_val(pmdp[1]) = _PAGE_TABLE_INV;
-        pmd_val(pmdp[2]) = _PAGE_TABLE_INV;
-        pmd_val(pmdp[3]) = _PAGE_TABLE_INV;
-}
-
-static inline void pmd_clear(pmd_t * pmdp)
-{
-        pmd_t *shadow_pmd = get_shadow_pmd(pmdp);
-
-        pmd_clear_kernel(pmdp);
-        if (shadow_pmd)
-                pmd_clear_kernel(shadow_pmd);
+        pmd_val(pmdp[0]) = _SEGMENT_ENTRY_EMPTY;
+        pmd_val(pmdp[1]) = _SEGMENT_ENTRY_EMPTY;
+        pmd_val(pmdp[2]) = _SEGMENT_ENTRY_EMPTY;
+        pmd_val(pmdp[3]) = _SEGMENT_ENTRY_EMPTY;
 }
 
 #else /* __s390x__ */
 
 static inline void pgd_clear_kernel(pgd_t * pgdp)
 {
-        pgd_val(*pgdp) = _PGD_ENTRY_INV | _PGD_ENTRY;
+        pgd_val(*pgdp) = _REGION3_ENTRY_EMPTY;
 }
 
 static inline void pgd_clear(pgd_t * pgdp)
 {
-        pgd_t *shadow_pgd = get_shadow_pgd(pgdp);
+        pgd_t *shadow_pgd = get_shadow_table(pgdp);
 
         pgd_clear_kernel(pgdp);
         if (shadow_pgd)
@@ -581,21 +554,21 @@ static inline void pgd_clear(pgd_t * pgdp)
 
 static inline void pmd_clear_kernel(pmd_t * pmdp)
 {
-        pmd_val(*pmdp) = _PMD_ENTRY_INV | _PMD_ENTRY;
-        pmd_val1(*pmdp) = _PMD_ENTRY_INV | _PMD_ENTRY;
+        pmd_val(*pmdp) = _SEGMENT_ENTRY_EMPTY;
+        pmd_val1(*pmdp) = _SEGMENT_ENTRY_EMPTY;
 }
 
+#endif /* __s390x__ */
+
 static inline void pmd_clear(pmd_t * pmdp)
 {
-        pmd_t *shadow_pmd = get_shadow_pmd(pmdp);
+        pmd_t *shadow_pmd = get_shadow_table(pmdp);
 
         pmd_clear_kernel(pmdp);
         if (shadow_pmd)
                 pmd_clear_kernel(shadow_pmd);
 }
 
-#endif /* __s390x__ */
-
 static inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 {
         pte_t *shadow_pte = get_shadow_pte(ptep);