arch/cris/include/asm/pgtable.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * CRIS pgtable.h - macros and functions to manipulate page tables.
   4  */
   5
   6 #ifndef _CRIS_PGTABLE_H
   7 #define _CRIS_PGTABLE_H
   8
   9 #include <asm/page.h>
  10 #define __ARCH_USE_5LEVEL_HACK
  11 #include <asm-generic/pgtable-nopmd.h>
  12
  13 #ifndef __ASSEMBLY__
  14 #include <linux/sched/mm.h>
  15 #include <asm/mmu.h>
  16 #endif
  17 #include <arch/pgtable.h>
  18
  19 /*
  20  * The Linux memory management assumes a three-level page table setup. On
  21  * CRIS, we use that, but "fold" the mid level into the top-level page
  22  * table. Since the MMU TLB is software loaded through an interrupt, it
  23  * supports any page table structure, so we could have used a three-level
  24  * setup, but for the amounts of memory we normally use, a two-level is
  25  * probably more efficient.
  26  *
  27  * This file contains the functions and defines necessary to modify and use
  28  * the CRIS page table tree.
  29  */
  30 #ifndef __ASSEMBLY__
  31 extern void paging_init(void);
  32 #endif
  33
  34 /* Certain architectures need to do special things when pte's
  35  * within a page table are directly modified.  Thus, the following
  36  * hook is made available.
  37  */
  38 #define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
  39 #define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
  40
  41 /*
  42  * (pmds are folded into pgds so this doesn't get actually called,
  43  * but the define is needed for a generic inline function.)
  44  */
  45 #define set_pmd(pmdptr, pmdval) (*(pmdptr) = pmdval)
  46 #define set_pgu(pudptr, pudval) (*(pudptr) = pudval)
  47
  48 /* PGDIR_SHIFT determines the size of the area a second-level page table can
  49  * map. It is equal to the page size times the number of PTE's that fit in
  50  * a PMD page. A PTE is 4-bytes in CRIS. Hence the following number.
  51  */
  52
  53 #define PGDIR_SHIFT     (PAGE_SHIFT + (PAGE_SHIFT-2))
  54 #define PGDIR_SIZE      (1UL << PGDIR_SHIFT)
  55 #define PGDIR_MASK      (~(PGDIR_SIZE-1))
  56
  57 /*
  58  * entries per page directory level: we use a two-level, so
  59  * we don't really have any PMD directory physically.
  60  * pointers are 4 bytes so we can use the page size and
  61  * divide it by 4 (shift by 2).
  62  */
  63 #define PTRS_PER_PTE    (1UL << (PAGE_SHIFT-2))
  64 #define PTRS_PER_PGD    (1UL << (PAGE_SHIFT-2))
  65
  66 /* calculate how many PGD entries a user-level program can use
  67  * the first mappable virtual address is 0
  68  * (TASK_SIZE is the maximum virtual address space)
  69  */
  70
  71 #define USER_PTRS_PER_PGD       (TASK_SIZE/PGDIR_SIZE)
  72 #define FIRST_USER_ADDRESS      0UL
  73
  74 /* zero page used for uninitialized stuff */
  75 #ifndef __ASSEMBLY__
  76 extern unsigned long empty_zero_page;
  77 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
  78 #endif
  79
  80 /* number of bits that fit into a memory pointer */
  81 #define BITS_PER_PTR                    (8*sizeof(unsigned long))
  82
  83 /* to align the pointer to a pointer address */
  84 #define PTR_MASK                        (~(sizeof(void*)-1))
  85
  86 /* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
  87 /* 64-bit machines, beware!  SRB. */
  88 #define SIZEOF_PTR_LOG2                 2
  89
  90 /* to find an entry in a page-table */
  91 #define PAGE_PTR(address) \
  92 ((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
  93
  94 /* to set the page-dir */
  95 #define SET_PAGE_DIR(tsk,pgdir)
  96
  97 #define pte_none(x)     (!pte_val(x))
  98 #define pte_present(x)  (pte_val(x) & _PAGE_PRESENT)
  99 #define pte_clear(mm,addr,xp)   do { pte_val(*(xp)) = 0; } while (0)
 100
 101 #define pmd_none(x)     (!pmd_val(x))
 102 /* by removing the _PAGE_KERNEL bit from the comparison, the same pmd_bad
 103  * works for both _PAGE_TABLE and _KERNPG_TABLE pmd entries.
 104  */
 105 #define pmd_bad(x)      ((pmd_val(x) & (~PAGE_MASK & ~_PAGE_KERNEL)) != _PAGE_TABLE)
 106 #define pmd_present(x)  (pmd_val(x) & _PAGE_PRESENT)
 107 #define pmd_clear(xp)   do { pmd_val(*(xp)) = 0; } while (0)
 108
 109 #ifndef __ASSEMBLY__
 110
 111 /*
 112  * The following only work if pte_present() is true.
 113  * Undefined behaviour if not..
 114  */
 115
 116 static inline int pte_write(pte_t pte)          { return pte_val(pte) & _PAGE_WRITE; }
 117 static inline int pte_dirty(pte_t pte)          { return pte_val(pte) & _PAGE_MODIFIED; }
 118 static inline int pte_young(pte_t pte)          { return pte_val(pte) & _PAGE_ACCESSED; }
 119 static inline int pte_special(pte_t pte)        { return 0; }
 120
 121 static inline pte_t pte_wrprotect(pte_t pte)
 122 {
 123         pte_val(pte) &= ~(_PAGE_WRITE | _PAGE_SILENT_WRITE);
 124         return pte;
 125 }
 126
 127 static inline pte_t pte_mkclean(pte_t pte)
 128 {
 129         pte_val(pte) &= ~(_PAGE_MODIFIED | _PAGE_SILENT_WRITE);
 130         return pte;
 131 }
 132
 133 static inline pte_t pte_mkold(pte_t pte)
 134 {
 135         pte_val(pte) &= ~(_PAGE_ACCESSED | _PAGE_SILENT_READ);
 136         return pte;
 137 }
 138
 139 static inline pte_t pte_mkwrite(pte_t pte)
 140 {
 141         pte_val(pte) |= _PAGE_WRITE;
 142         if (pte_val(pte) & _PAGE_MODIFIED)
 143                 pte_val(pte) |= _PAGE_SILENT_WRITE;
 144         return pte;
 145 }
 146
 147 static inline pte_t pte_mkdirty(pte_t pte)
 148 {
 149         pte_val(pte) |= _PAGE_MODIFIED;
 150         if (pte_val(pte) & _PAGE_WRITE)
 151                 pte_val(pte) |= _PAGE_SILENT_WRITE;
 152         return pte;
 153 }
 154
 155 static inline pte_t pte_mkyoung(pte_t pte)
 156 {
 157         pte_val(pte) |= _PAGE_ACCESSED;
 158         if (pte_val(pte) & _PAGE_READ)
 159         {
 160                 pte_val(pte) |= _PAGE_SILENT_READ;
 161                 if ((pte_val(pte) & (_PAGE_WRITE | _PAGE_MODIFIED)) ==
 162                     (_PAGE_WRITE | _PAGE_MODIFIED))
 163                         pte_val(pte) |= _PAGE_SILENT_WRITE;
 164         }
 165         return pte;
 166 }
 167 static inline pte_t pte_mkspecial(pte_t pte)    { return pte; }
 168
 169 /*
 170  * Conversion functions: convert a page and protection to a page entry,
 171  * and a page entry and page directory to the page they refer to.
 172  */
 173
 174 /* What actually goes as arguments to the various functions is less than
 175  * obvious, but a rule of thumb is that struct page's goes as struct page *,
 176  * really physical DRAM addresses are unsigned long's, and DRAM "virtual"
 177  * addresses (the 0xc0xxxxxx's) goes as void *'s.
 178  */
 179
 180 static inline pte_t __mk_pte(void * page, pgprot_t pgprot)
 181 {
 182         pte_t pte;
 183         /* the PTE needs a physical address */
 184         pte_val(pte) = __pa(page) | pgprot_val(pgprot);
 185         return pte;
 186 }
 187
 188 #define mk_pte(page, pgprot) __mk_pte(page_address(page), (pgprot))
 189
 190 #define mk_pte_phys(physpage, pgprot) \
 191 ({                                                                      \
 192         pte_t __pte;                                                    \
 193                                                                         \
 194         pte_val(__pte) = (physpage) + pgprot_val(pgprot);               \
 195         __pte;                                                          \
 196 })
 197
 198 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 199 { pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }
 200
 201 #define pgprot_noncached(prot) __pgprot((pgprot_val(prot) | _PAGE_NO_CACHE))
 202
 203
 204 /* pte_val refers to a page in the 0x4xxxxxxx physical DRAM interval
 205  * __pte_page(pte_val) refers to the "virtual" DRAM interval
 206  * pte_pagenr refers to the page-number counted starting from the virtual DRAM start
 207  */
 208
 209 static inline unsigned long __pte_page(pte_t pte)
 210 {
 211         /* the PTE contains a physical address */
 212         return (unsigned long)__va(pte_val(pte) & PAGE_MASK);
 213 }
 214
 215 #define pte_pagenr(pte)         ((__pte_page(pte) - PAGE_OFFSET) >> PAGE_SHIFT)
 216
 217 /* permanent address of a page */
 218
 219 #define __page_address(page)    (PAGE_OFFSET + (((page) - mem_map) << PAGE_SHIFT))
 220 #define pte_page(pte)           (mem_map+pte_pagenr(pte))
 221
 222 /* only the pte's themselves need to point to physical DRAM (see above)
 223  * the pagetable links are purely handled within the kernel SW and thus
 224  * don't need the __pa and __va transformations.
 225  */
 226
 227 static inline void pmd_set(pmd_t * pmdp, pte_t * ptep)
 228 { pmd_val(*pmdp) = _PAGE_TABLE | (unsigned long) ptep; }
 229
 230 #define pmd_page(pmd)           (pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT))
 231 #define pmd_page_vaddr(pmd)     ((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
 232
 233 /* to find an entry in a page-table-directory. */
 234 #define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
 235
 236 /* to find an entry in a page-table-directory */
 237 static inline pgd_t * pgd_offset(const struct mm_struct *mm, unsigned long address)
 238 {
 239         return mm->pgd + pgd_index(address);
 240 }
 241
 242 /* to find an entry in a kernel page-table-directory */
 243 #define pgd_offset_k(address) pgd_offset(&init_mm, address)
 244
 245 /* Find an entry in the third-level page table.. */
 246 #define __pte_offset(address) \
 247         (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 248 #define pte_offset_kernel(dir, address) \
 249         ((pte_t *) pmd_page_vaddr(*(dir)) +  __pte_offset(address))
 250 #define pte_offset_map(dir, address) \
 251         ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
 252
 253 #define pte_unmap(pte) do { } while (0)
 254 #define pte_pfn(x)              ((unsigned long)(__va((x).pte)) >> PAGE_SHIFT)
 255 #define pfn_pte(pfn, prot)      __pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
 256
 257 #define pte_ERROR(e) \
 258         printk("%s:%d: bad pte %p(%08lx).\n", __FILE__, __LINE__, &(e), pte_val(e))
 259 #define pgd_ERROR(e) \
 260         printk("%s:%d: bad pgd %p(%08lx).\n", __FILE__, __LINE__, &(e), pgd_val(e))
 261
 262
 263 extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; /* defined in head.S */
 264
 265 /*
 266  * CRIS doesn't have any external MMU info: the kernel page
 267  * tables contain all the necessary information.
 268  *
 269  * Actually I am not sure on what this could be used for.
 270  */
 271 static inline void update_mmu_cache(struct vm_area_struct * vma,
 272         unsigned long address, pte_t *ptep)
 273 {
 274 }
 275
 276 /* Encode and de-code a swap entry (must be !pte_none(e) && !pte_present(e)) */
 277 /* Since the PAGE_PRESENT bit is bit 4, we can use the bits above */
 278
 279 #define __swp_type(x)                   (((x).val >> 5) & 0x7f)
 280 #define __swp_offset(x)                 ((x).val >> 12)
 281 #define __swp_entry(type, offset)       ((swp_entry_t) { ((type) << 5) | ((offset) << 12) })
 282 #define __pte_to_swp_entry(pte)         ((swp_entry_t) { pte_val(pte) })
 283 #define __swp_entry_to_pte(x)           ((pte_t) { (x).val })
 284
 285 #define kern_addr_valid(addr)   (1)
 286
 287 #include <asm-generic/pgtable.h>
 288
 289 /*
 290  * No page table caches to initialise
 291  */
 292 #define pgtable_cache_init()   do { } while (0)
 293
 294 typedef pte_t *pte_addr_t;
 295
 296 #endif /* __ASSEMBLY__ */
 297 #endif /* _CRIS_PGTABLE_H */