1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ALPHA_PGTABLE_H 3 #define _ALPHA_PGTABLE_H 4 5 #include <asm-generic/pgtable-nopud.h> 6 7 /* 8 * This file contains the functions and defines necessary to modify and use 9 * the Alpha page table tree. 10 * 11 * This hopefully works with any standard Alpha page-size, as defined 12 * in <asm/page.h> (currently 8192). 13 */ 14 #include <linux/mmzone.h> 15 16 #include <asm/page.h> 17 #include <asm/processor.h> /* For TASK_SIZE */ 18 #include <asm/machvec.h> 19 #include <asm/setup.h> 20 21 struct mm_struct; 22 struct vm_area_struct; 23 24 /* Certain architectures need to do special things when PTEs 25 * within a page table are directly modified. Thus, the following 26 * hook is made available. 27 */ 28 #define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval)) 29 #define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval) 30 31 /* PMD_SHIFT determines the size of the area a second-level page table can map */ 32 #define PMD_SHIFT (PAGE_SHIFT + (PAGE_SHIFT-3)) 33 #define PMD_SIZE (1UL << PMD_SHIFT) 34 #define PMD_MASK (~(PMD_SIZE-1)) 35 36 /* PGDIR_SHIFT determines what a third-level page table entry can map */ 37 #define PGDIR_SHIFT (PAGE_SHIFT + 2*(PAGE_SHIFT-3)) 38 #define PGDIR_SIZE (1UL << PGDIR_SHIFT) 39 #define PGDIR_MASK (~(PGDIR_SIZE-1)) 40 41 /* 42 * Entries per page directory level: the Alpha is three-level, with 43 * all levels having a one-page page table. 44 */ 45 #define PTRS_PER_PTE (1UL << (PAGE_SHIFT-3)) 46 #define PTRS_PER_PMD (1UL << (PAGE_SHIFT-3)) 47 #define PTRS_PER_PGD (1UL << (PAGE_SHIFT-3)) 48 #define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE) 49 50 /* Number of pointers that fit on a page: this will go away. */ 51 #define PTRS_PER_PAGE (1UL << (PAGE_SHIFT-3)) 52 53 #ifdef CONFIG_ALPHA_LARGE_VMALLOC 54 #define VMALLOC_START 0xfffffe0000000000 55 #else 56 #define VMALLOC_START (-2*PGDIR_SIZE) 57 #endif 58 #define VMALLOC_END (-PGDIR_SIZE) 59 60 /* 61 * OSF/1 PAL-code-imposed page table bits 62 */ 63 #define _PAGE_VALID 0x0001 64 #define _PAGE_FOR 0x0002 /* used for page protection (fault on read) */ 65 #define _PAGE_FOW 0x0004 /* used for page protection (fault on write) */ 66 #define _PAGE_FOE 0x0008 /* used for page protection (fault on exec) */ 67 #define _PAGE_ASM 0x0010 68 #define _PAGE_KRE 0x0100 /* xxx - see below on the "accessed" bit */ 69 #define _PAGE_URE 0x0200 /* xxx */ 70 #define _PAGE_KWE 0x1000 /* used to do the dirty bit in software */ 71 #define _PAGE_UWE 0x2000 /* used to do the dirty bit in software */ 72 73 /* .. and these are ours ... */ 74 #define _PAGE_DIRTY 0x20000 75 #define _PAGE_ACCESSED 0x40000 76 77 /* 78 * NOTE! The "accessed" bit isn't necessarily exact: it can be kept exactly 79 * by software (use the KRE/URE/KWE/UWE bits appropriately), but I'll fake it. 80 * Under Linux/AXP, the "accessed" bit just means "read", and I'll just use 81 * the KRE/URE bits to watch for it. That way we don't need to overload the 82 * KWE/UWE bits with both handling dirty and accessed. 83 * 84 * Note that the kernel uses the accessed bit just to check whether to page 85 * out a page or not, so it doesn't have to be exact anyway. 86 */ 87 88 #define __DIRTY_BITS (_PAGE_DIRTY | _PAGE_KWE | _PAGE_UWE) 89 #define __ACCESS_BITS (_PAGE_ACCESSED | _PAGE_KRE | _PAGE_URE) 90 91 #define _PFN_MASK 0xFFFFFFFF00000000UL 92 93 #define _PAGE_TABLE (_PAGE_VALID | __DIRTY_BITS | __ACCESS_BITS) 94 #define _PAGE_CHG_MASK (_PFN_MASK | __DIRTY_BITS | __ACCESS_BITS) 95 96 /* 97 * All the normal masks have the "page accessed" bits on, as any time they are used, 98 * the page is accessed. They are cleared only by the page-out routines 99 */ 100 #define PAGE_NONE __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOR | _PAGE_FOW | _PAGE_FOE) 101 #define PAGE_SHARED __pgprot(_PAGE_VALID | __ACCESS_BITS) 102 #define PAGE_COPY __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW) 103 #define PAGE_READONLY __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW) 104 #define PAGE_KERNEL __pgprot(_PAGE_VALID | _PAGE_ASM | _PAGE_KRE | _PAGE_KWE) 105 106 #define _PAGE_NORMAL(x) __pgprot(_PAGE_VALID | __ACCESS_BITS | (x)) 107 108 #define _PAGE_P(x) _PAGE_NORMAL((x) | (((x) & _PAGE_FOW)?0:_PAGE_FOW)) 109 #define _PAGE_S(x) _PAGE_NORMAL(x) 110 111 /* 112 * The hardware can handle write-only mappings, but as the Alpha 113 * architecture does byte-wide writes with a read-modify-write 114 * sequence, it's not practical to have write-without-read privs. 115 * Thus the "-w- -> rw-" and "-wx -> rwx" mapping here (and in 116 * arch/alpha/mm/fault.c) 117 */ 118 /* xwr */ 119 120 /* 121 * pgprot_noncached() is only for infiniband pci support, and a real 122 * implementation for RAM would be more complicated. 123 */ 124 #define pgprot_noncached(prot) (prot) 125 126 /* 127 * BAD_PAGETABLE is used when we need a bogus page-table, while 128 * BAD_PAGE is used for a bogus page. 129 * 130 * ZERO_PAGE is a global shared page that is always zero: used 131 * for zero-mapped memory areas etc.. 132 */ 133 extern pte_t __bad_page(void); 134 extern pmd_t * __bad_pagetable(void); 135 136 extern unsigned long __zero_page(void); 137 138 #define BAD_PAGETABLE __bad_pagetable() 139 #define BAD_PAGE __bad_page() 140 #define ZERO_PAGE(vaddr) (virt_to_page(ZERO_PGE)) 141 142 /* number of bits that fit into a memory pointer */ 143 #define BITS_PER_PTR (8*sizeof(unsigned long)) 144 145 /* to align the pointer to a pointer address */ 146 #define PTR_MASK (~(sizeof(void*)-1)) 147 148 /* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */ 149 #define SIZEOF_PTR_LOG2 3 150 151 /* to find an entry in a page-table */ 152 #define PAGE_PTR(address) \ 153 ((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK) 154 155 /* 156 * On certain platforms whose physical address space can overlap KSEG, 157 * namely EV6 and above, we must re-twiddle the physaddr to restore the 158 * correct high-order bits. 159 * 160 * This is extremely confusing until you realize that this is actually 161 * just working around a userspace bug. The X server was intending to 162 * provide the physical address but instead provided the KSEG address. 163 * Or tried to, except it's not representable. 164 * 165 * On Tsunami there's nothing meaningful at 0x40000000000, so this is 166 * a safe thing to do. Come the first core logic that does put something 167 * in this area -- memory or whathaveyou -- then this hack will have 168 * to go away. So be prepared! 169 */ 170 171 #if defined(CONFIG_ALPHA_GENERIC) && defined(USE_48_BIT_KSEG) 172 #error "EV6-only feature in a generic kernel" 173 #endif 174 #if defined(CONFIG_ALPHA_GENERIC) || \ 175 (defined(CONFIG_ALPHA_EV6) && !defined(USE_48_BIT_KSEG)) 176 #define KSEG_PFN (0xc0000000000UL >> PAGE_SHIFT) 177 #define PHYS_TWIDDLE(pfn) \ 178 ((((pfn) & KSEG_PFN) == (0x40000000000UL >> PAGE_SHIFT)) \ 179 ? ((pfn) ^= KSEG_PFN) : (pfn)) 180 #else 181 #define PHYS_TWIDDLE(pfn) (pfn) 182 #endif 183 184 /* 185 * Conversion functions: convert a page and protection to a page entry, 186 * and a page entry and page directory to the page they refer to. 187 */ 188 #define page_to_pa(page) (page_to_pfn(page) << PAGE_SHIFT) 189 #define pte_pfn(pte) (pte_val(pte) >> 32) 190 191 #define pte_page(pte) pfn_to_page(pte_pfn(pte)) 192 #define mk_pte(page, pgprot) \ 193 ({ \ 194 pte_t pte; \ 195 \ 196 pte_val(pte) = (page_to_pfn(page) << 32) | pgprot_val(pgprot); \ 197 pte; \ 198 }) 199 200 extern inline pte_t pfn_pte(unsigned long physpfn, pgprot_t pgprot) 201 { pte_t pte; pte_val(pte) = (PHYS_TWIDDLE(physpfn) << 32) | pgprot_val(pgprot); return pte; } 202 203 extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot) 204 { pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; } 205 206 extern inline void pmd_set(pmd_t * pmdp, pte_t * ptep) 207 { pmd_val(*pmdp) = _PAGE_TABLE | ((((unsigned long) ptep) - PAGE_OFFSET) << (32-PAGE_SHIFT)); } 208 209 extern inline void pud_set(pud_t * pudp, pmd_t * pmdp) 210 { pud_val(*pudp) = _PAGE_TABLE | ((((unsigned long) pmdp) - PAGE_OFFSET) << (32-PAGE_SHIFT)); } 211 212 213 extern inline unsigned long 214 pmd_page_vaddr(pmd_t pmd) 215 { 216 return ((pmd_val(pmd) & _PFN_MASK) >> (32-PAGE_SHIFT)) + PAGE_OFFSET; 217 } 218 219 #define pmd_pfn(pmd) (pmd_val(pmd) >> 32) 220 #define pmd_page(pmd) (pfn_to_page(pmd_val(pmd) >> 32)) 221 #define pud_page(pud) (pfn_to_page(pud_val(pud) >> 32)) 222 223 extern inline pmd_t *pud_pgtable(pud_t pgd) 224 { 225 return (pmd_t *)(PAGE_OFFSET + ((pud_val(pgd) & _PFN_MASK) >> (32-PAGE_SHIFT))); 226 } 227 228 extern inline int pte_none(pte_t pte) { return !pte_val(pte); } 229 extern inline int pte_present(pte_t pte) { return pte_val(pte) & _PAGE_VALID; } 230 extern inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) 231 { 232 pte_val(*ptep) = 0; 233 } 234 235 extern inline int pmd_none(pmd_t pmd) { return !pmd_val(pmd); } 236 extern inline int pmd_bad(pmd_t pmd) { return (pmd_val(pmd) & ~_PFN_MASK) != _PAGE_TABLE; } 237 extern inline int pmd_present(pmd_t pmd) { return pmd_val(pmd) & _PAGE_VALID; } 238 extern inline void pmd_clear(pmd_t * pmdp) { pmd_val(*pmdp) = 0; } 239 240 extern inline int pud_none(pud_t pud) { return !pud_val(pud); } 241 extern inline int pud_bad(pud_t pud) { return (pud_val(pud) & ~_PFN_MASK) != _PAGE_TABLE; } 242 extern inline int pud_present(pud_t pud) { return pud_val(pud) & _PAGE_VALID; } 243 extern inline void pud_clear(pud_t * pudp) { pud_val(*pudp) = 0; } 244 245 /* 246 * The following only work if pte_present() is true. 247 * Undefined behaviour if not.. 248 */ 249 extern inline int pte_write(pte_t pte) { return !(pte_val(pte) & _PAGE_FOW); } 250 extern inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; } 251 extern inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; } 252 253 extern inline pte_t pte_wrprotect(pte_t pte) { pte_val(pte) |= _PAGE_FOW; return pte; } 254 extern inline pte_t pte_mkclean(pte_t pte) { pte_val(pte) &= ~(__DIRTY_BITS); return pte; } 255 extern inline pte_t pte_mkold(pte_t pte) { pte_val(pte) &= ~(__ACCESS_BITS); return pte; } 256 extern inline pte_t pte_mkwrite(pte_t pte) { pte_val(pte) &= ~_PAGE_FOW; return pte; } 257 extern inline pte_t pte_mkdirty(pte_t pte) { pte_val(pte) |= __DIRTY_BITS; return pte; } 258 extern inline pte_t pte_mkyoung(pte_t pte) { pte_val(pte) |= __ACCESS_BITS; return pte; } 259 260 /* 261 * The smp_rmb() in the following functions are required to order the load of 262 * *dir (the pointer in the top level page table) with any subsequent load of 263 * the returned pmd_t *ret (ret is data dependent on *dir). 264 * 265 * If this ordering is not enforced, the CPU might load an older value of 266 * *ret, which may be uninitialized data. See mm/memory.c:__pte_alloc for 267 * more details. 268 * 269 * Note that we never change the mm->pgd pointer after the task is running, so 270 * pgd_offset does not require such a barrier. 271 */ 272 273 /* Find an entry in the second-level page table.. */ 274 extern inline pmd_t * pmd_offset(pud_t * dir, unsigned long address) 275 { 276 pmd_t *ret = pud_pgtable(*dir) + ((address >> PMD_SHIFT) & (PTRS_PER_PAGE - 1)); 277 smp_rmb(); /* see above */ 278 return ret; 279 } 280 #define pmd_offset pmd_offset 281 282 /* Find an entry in the third-level page table.. */ 283 extern inline pte_t * pte_offset_kernel(pmd_t * dir, unsigned long address) 284 { 285 pte_t *ret = (pte_t *) pmd_page_vaddr(*dir) 286 + ((address >> PAGE_SHIFT) & (PTRS_PER_PAGE - 1)); 287 smp_rmb(); /* see above */ 288 return ret; 289 } 290 #define pte_offset_kernel pte_offset_kernel 291 292 extern pgd_t swapper_pg_dir[1024]; 293 294 /* 295 * The Alpha doesn't have any external MMU info: the kernel page 296 * tables contain all the necessary information. 297 */ 298 extern inline void update_mmu_cache(struct vm_area_struct * vma, 299 unsigned long address, pte_t *ptep) 300 { 301 } 302 303 /* 304 * Non-present pages: high 24 bits are offset, next 8 bits type, 305 * low 32 bits zero. 306 */ 307 extern inline pte_t mk_swap_pte(unsigned long type, unsigned long offset) 308 { pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; } 309 310 #define __swp_type(x) (((x).val >> 32) & 0xff) 311 #define __swp_offset(x) ((x).val >> 40) 312 #define __swp_entry(type, off) ((swp_entry_t) { pte_val(mk_swap_pte((type), (off))) }) 313 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) 314 #define __swp_entry_to_pte(x) ((pte_t) { (x).val }) 315 316 #define pte_ERROR(e) \ 317 printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e)) 318 #define pmd_ERROR(e) \ 319 printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e)) 320 #define pgd_ERROR(e) \ 321 printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e)) 322 323 extern void paging_init(void); 324 325 /* We have our own get_unmapped_area to cope with ADDR_LIMIT_32BIT. */ 326 #define HAVE_ARCH_UNMAPPED_AREA 327 328 #endif /* _ALPHA_PGTABLE_H */ 329