1 /* 2 * include/asm-xtensa/pgtable.h 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * Copyright (C) 2001 - 2013 Tensilica Inc. 9 */ 10 11 #ifndef _XTENSA_PGTABLE_H 12 #define _XTENSA_PGTABLE_H 13 14 #include <asm-generic/pgtable-nopmd.h> 15 #include <asm/page.h> 16 17 /* 18 * We only use two ring levels, user and kernel space. 19 */ 20 21 #define USER_RING 1 /* user ring level */ 22 #define KERNEL_RING 0 /* kernel ring level */ 23 24 /* 25 * The Xtensa architecture port of Linux has a two-level page table system, 26 * i.e. the logical three-level Linux page table layout is folded. 27 * Each task has the following memory page tables: 28 * 29 * PGD table (page directory), ie. 3rd-level page table: 30 * One page (4 kB) of 1024 (PTRS_PER_PGD) pointers to PTE tables 31 * (Architectures that don't have the PMD folded point to the PMD tables) 32 * 33 * The pointer to the PGD table for a given task can be retrieved from 34 * the task structure (struct task_struct*) t, e.g. current(): 35 * (t->mm ? t->mm : t->active_mm)->pgd 36 * 37 * PMD tables (page middle-directory), ie. 2nd-level page tables: 38 * Absent for the Xtensa architecture (folded, PTRS_PER_PMD == 1). 39 * 40 * PTE tables (page table entry), ie. 1st-level page tables: 41 * One page (4 kB) of 1024 (PTRS_PER_PTE) PTEs with a special PTE 42 * invalid_pte_table for absent mappings. 43 * 44 * The individual pages are 4 kB big with special pages for the empty_zero_page. 45 */ 46 47 #define PGDIR_SHIFT 22 48 #define PGDIR_SIZE (1UL << PGDIR_SHIFT) 49 #define PGDIR_MASK (~(PGDIR_SIZE-1)) 50 51 /* 52 * Entries per page directory level: we use two-level, so 53 * we don't really have any PMD directory physically. 54 */ 55 #define PTRS_PER_PTE 1024 56 #define PTRS_PER_PTE_SHIFT 10 57 #define PTRS_PER_PGD 1024 58 #define PGD_ORDER 0 59 #define USER_PTRS_PER_PGD (TASK_SIZE/PGDIR_SIZE) 60 #define FIRST_USER_ADDRESS 0UL 61 #define FIRST_USER_PGD_NR (FIRST_USER_ADDRESS >> PGDIR_SHIFT) 62 63 /* 64 * Virtual memory area. We keep a distance to other memory regions to be 65 * on the safe side. We also use this area for cache aliasing. 66 */ 67 #define VMALLOC_START 0xC0000000 68 #define VMALLOC_END 0xC7FEFFFF 69 #define TLBTEMP_BASE_1 0xC7FF0000 70 #define TLBTEMP_BASE_2 (TLBTEMP_BASE_1 + DCACHE_WAY_SIZE) 71 #if 2 * DCACHE_WAY_SIZE > ICACHE_WAY_SIZE 72 #define TLBTEMP_SIZE (2 * DCACHE_WAY_SIZE) 73 #else 74 #define TLBTEMP_SIZE ICACHE_WAY_SIZE 75 #endif 76 77 /* 78 * For the Xtensa architecture, the PTE layout is as follows: 79 * 80 * 31------12 11 10-9 8-6 5-4 3-2 1-0 81 * +-----------------------------------------+ 82 * | | Software | HARDWARE | 83 * | PPN | ADW | RI |Attribute| 84 * +-----------------------------------------+ 85 * pte_none | MBZ | 01 | 11 | 00 | 86 * +-----------------------------------------+ 87 * present | PPN | 0 | 00 | ADW | RI | CA | wx | 88 * +- - - - - - - - - - - - - - - - - - - - -+ 89 * (PAGE_NONE)| PPN | 0 | 00 | ADW | 01 | 11 | 11 | 90 * +-----------------------------------------+ 91 * swap | index | type | 01 | 11 | 00 | 92 * +-----------------------------------------+ 93 * 94 * For T1050 hardware and earlier the layout differs for present and (PAGE_NONE) 95 * +-----------------------------------------+ 96 * present | PPN | 0 | 00 | ADW | RI | CA | w1 | 97 * +-----------------------------------------+ 98 * (PAGE_NONE)| PPN | 0 | 00 | ADW | 01 | 01 | 00 | 99 * +-----------------------------------------+ 100 * 101 * Legend: 102 * PPN Physical Page Number 103 * ADW software: accessed (young) / dirty / writable 104 * RI ring (0=privileged, 1=user, 2 and 3 are unused) 105 * CA cache attribute: 00 bypass, 01 writeback, 10 writethrough 106 * (11 is invalid and used to mark pages that are not present) 107 * w page is writable (hw) 108 * x page is executable (hw) 109 * index swap offset / PAGE_SIZE (bit 11-31: 21 bits -> 8 GB) 110 * (note that the index is always non-zero) 111 * type swap type (5 bits -> 32 types) 112 * 113 * Notes: 114 * - (PROT_NONE) is a special case of 'present' but causes an exception for 115 * any access (read, write, and execute). 116 * - 'multihit-exception' has the highest priority of all MMU exceptions, 117 * so the ring must be set to 'RING_USER' even for 'non-present' pages. 118 * - on older hardware, the exectuable flag was not supported and 119 * used as a 'valid' flag, so it needs to be always set. 120 * - we need to keep track of certain flags in software (dirty and young) 121 * to do this, we use write exceptions and have a separate software w-flag. 122 * - attribute value 1101 (and 1111 on T1050 and earlier) is reserved 123 */ 124 125 #define _PAGE_ATTRIB_MASK 0xf 126 127 #define _PAGE_HW_EXEC (1<<0) /* hardware: page is executable */ 128 #define _PAGE_HW_WRITE (1<<1) /* hardware: page is writable */ 129 130 #define _PAGE_CA_BYPASS (0<<2) /* bypass, non-speculative */ 131 #define _PAGE_CA_WB (1<<2) /* write-back */ 132 #define _PAGE_CA_WT (2<<2) /* write-through */ 133 #define _PAGE_CA_MASK (3<<2) 134 #define _PAGE_CA_INVALID (3<<2) 135 136 /* We use invalid attribute values to distinguish special pte entries */ 137 #if XCHAL_HW_VERSION_MAJOR < 2000 138 #define _PAGE_HW_VALID 0x01 /* older HW needed this bit set */ 139 #define _PAGE_NONE 0x04 140 #else 141 #define _PAGE_HW_VALID 0x00 142 #define _PAGE_NONE 0x0f 143 #endif 144 145 #define _PAGE_USER (1<<4) /* user access (ring=1) */ 146 147 /* Software */ 148 #define _PAGE_WRITABLE_BIT 6 149 #define _PAGE_WRITABLE (1<<6) /* software: page writable */ 150 #define _PAGE_DIRTY (1<<7) /* software: page dirty */ 151 #define _PAGE_ACCESSED (1<<8) /* software: page accessed (read) */ 152 153 #ifdef CONFIG_MMU 154 155 #define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY) 156 #define _PAGE_PRESENT (_PAGE_HW_VALID | _PAGE_CA_WB | _PAGE_ACCESSED) 157 158 #define PAGE_NONE __pgprot(_PAGE_NONE | _PAGE_USER) 159 #define PAGE_COPY __pgprot(_PAGE_PRESENT | _PAGE_USER) 160 #define PAGE_COPY_EXEC __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_HW_EXEC) 161 #define PAGE_READONLY __pgprot(_PAGE_PRESENT | _PAGE_USER) 162 #define PAGE_READONLY_EXEC __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_HW_EXEC) 163 #define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_WRITABLE) 164 #define PAGE_SHARED_EXEC \ 165 __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_WRITABLE | _PAGE_HW_EXEC) 166 #define PAGE_KERNEL __pgprot(_PAGE_PRESENT | _PAGE_HW_WRITE) 167 #define PAGE_KERNEL_EXEC __pgprot(_PAGE_PRESENT|_PAGE_HW_WRITE|_PAGE_HW_EXEC) 168 169 #if (DCACHE_WAY_SIZE > PAGE_SIZE) 170 # define _PAGE_DIRECTORY (_PAGE_HW_VALID | _PAGE_ACCESSED | _PAGE_CA_BYPASS) 171 #else 172 # define _PAGE_DIRECTORY (_PAGE_HW_VALID | _PAGE_ACCESSED | _PAGE_CA_WB) 173 #endif 174 175 #else /* no mmu */ 176 177 # define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY) 178 # define PAGE_NONE __pgprot(0) 179 # define PAGE_SHARED __pgprot(0) 180 # define PAGE_COPY __pgprot(0) 181 # define PAGE_READONLY __pgprot(0) 182 # define PAGE_KERNEL __pgprot(0) 183 184 #endif 185 186 /* 187 * On certain configurations of Xtensa MMUs (eg. the initial Linux config), 188 * the MMU can't do page protection for execute, and considers that the same as 189 * read. Also, write permissions may imply read permissions. 190 * What follows is the closest we can get by reasonable means.. 191 * See linux/mm/mmap.c for protection_map[] array that uses these definitions. 192 */ 193 #define __P000 PAGE_NONE /* private --- */ 194 #define __P001 PAGE_READONLY /* private --r */ 195 #define __P010 PAGE_COPY /* private -w- */ 196 #define __P011 PAGE_COPY /* private -wr */ 197 #define __P100 PAGE_READONLY_EXEC /* private x-- */ 198 #define __P101 PAGE_READONLY_EXEC /* private x-r */ 199 #define __P110 PAGE_COPY_EXEC /* private xw- */ 200 #define __P111 PAGE_COPY_EXEC /* private xwr */ 201 202 #define __S000 PAGE_NONE /* shared --- */ 203 #define __S001 PAGE_READONLY /* shared --r */ 204 #define __S010 PAGE_SHARED /* shared -w- */ 205 #define __S011 PAGE_SHARED /* shared -wr */ 206 #define __S100 PAGE_READONLY_EXEC /* shared x-- */ 207 #define __S101 PAGE_READONLY_EXEC /* shared x-r */ 208 #define __S110 PAGE_SHARED_EXEC /* shared xw- */ 209 #define __S111 PAGE_SHARED_EXEC /* shared xwr */ 210 211 #ifndef __ASSEMBLY__ 212 213 #define pte_ERROR(e) \ 214 printk("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e)) 215 #define pgd_ERROR(e) \ 216 printk("%s:%d: bad pgd entry %08lx.\n", __FILE__, __LINE__, pgd_val(e)) 217 218 extern unsigned long empty_zero_page[1024]; 219 220 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page)) 221 222 #ifdef CONFIG_MMU 223 extern pgd_t swapper_pg_dir[PAGE_SIZE/sizeof(pgd_t)]; 224 extern void paging_init(void); 225 #else 226 # define swapper_pg_dir NULL 227 static inline void paging_init(void) { } 228 #endif 229 static inline void pgtable_cache_init(void) { } 230 231 /* 232 * The pmd contains the kernel virtual address of the pte page. 233 */ 234 #define pmd_page_vaddr(pmd) ((unsigned long)(pmd_val(pmd) & PAGE_MASK)) 235 #define pmd_page(pmd) virt_to_page(pmd_val(pmd)) 236 237 /* 238 * pte status. 239 */ 240 # define pte_none(pte) (pte_val(pte) == (_PAGE_CA_INVALID | _PAGE_USER)) 241 #if XCHAL_HW_VERSION_MAJOR < 2000 242 # define pte_present(pte) ((pte_val(pte) & _PAGE_CA_MASK) != _PAGE_CA_INVALID) 243 #else 244 # define pte_present(pte) \ 245 (((pte_val(pte) & _PAGE_CA_MASK) != _PAGE_CA_INVALID) \ 246 || ((pte_val(pte) & _PAGE_ATTRIB_MASK) == _PAGE_NONE)) 247 #endif 248 #define pte_clear(mm,addr,ptep) \ 249 do { update_pte(ptep, __pte(_PAGE_CA_INVALID | _PAGE_USER)); } while (0) 250 251 #define pmd_none(pmd) (!pmd_val(pmd)) 252 #define pmd_present(pmd) (pmd_val(pmd) & PAGE_MASK) 253 #define pmd_bad(pmd) (pmd_val(pmd) & ~PAGE_MASK) 254 #define pmd_clear(pmdp) do { set_pmd(pmdp, __pmd(0)); } while (0) 255 256 static inline int pte_write(pte_t pte) { return pte_val(pte) & _PAGE_WRITABLE; } 257 static inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; } 258 static inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; } 259 static inline int pte_special(pte_t pte) { return 0; } 260 261 static inline pte_t pte_wrprotect(pte_t pte) 262 { pte_val(pte) &= ~(_PAGE_WRITABLE | _PAGE_HW_WRITE); return pte; } 263 static inline pte_t pte_mkclean(pte_t pte) 264 { pte_val(pte) &= ~(_PAGE_DIRTY | _PAGE_HW_WRITE); return pte; } 265 static inline pte_t pte_mkold(pte_t pte) 266 { pte_val(pte) &= ~_PAGE_ACCESSED; return pte; } 267 static inline pte_t pte_mkdirty(pte_t pte) 268 { pte_val(pte) |= _PAGE_DIRTY; return pte; } 269 static inline pte_t pte_mkyoung(pte_t pte) 270 { pte_val(pte) |= _PAGE_ACCESSED; return pte; } 271 static inline pte_t pte_mkwrite(pte_t pte) 272 { pte_val(pte) |= _PAGE_WRITABLE; return pte; } 273 static inline pte_t pte_mkspecial(pte_t pte) 274 { return pte; } 275 276 #define pgprot_noncached(prot) (__pgprot(pgprot_val(prot) & ~_PAGE_CA_MASK)) 277 278 /* 279 * Conversion functions: convert a page and protection to a page entry, 280 * and a page entry and page directory to the page they refer to. 281 */ 282 283 #define pte_pfn(pte) (pte_val(pte) >> PAGE_SHIFT) 284 #define pte_same(a,b) (pte_val(a) == pte_val(b)) 285 #define pte_page(x) pfn_to_page(pte_pfn(x)) 286 #define pfn_pte(pfn, prot) __pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot)) 287 #define mk_pte(page, prot) pfn_pte(page_to_pfn(page), prot) 288 289 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) 290 { 291 return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot)); 292 } 293 294 /* 295 * Certain architectures need to do special things when pte's 296 * within a page table are directly modified. Thus, the following 297 * hook is made available. 298 */ 299 static inline void update_pte(pte_t *ptep, pte_t pteval) 300 { 301 *ptep = pteval; 302 #if (DCACHE_WAY_SIZE > PAGE_SIZE) && XCHAL_DCACHE_IS_WRITEBACK 303 __asm__ __volatile__ ("dhwb %0, 0" :: "a" (ptep)); 304 #endif 305 306 } 307 308 struct mm_struct; 309 310 static inline void 311 set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pteval) 312 { 313 update_pte(ptep, pteval); 314 } 315 316 static inline void set_pte(pte_t *ptep, pte_t pteval) 317 { 318 update_pte(ptep, pteval); 319 } 320 321 static inline void 322 set_pmd(pmd_t *pmdp, pmd_t pmdval) 323 { 324 *pmdp = pmdval; 325 } 326 327 struct vm_area_struct; 328 329 static inline int 330 ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr, 331 pte_t *ptep) 332 { 333 pte_t pte = *ptep; 334 if (!pte_young(pte)) 335 return 0; 336 update_pte(ptep, pte_mkold(pte)); 337 return 1; 338 } 339 340 static inline pte_t 341 ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) 342 { 343 pte_t pte = *ptep; 344 pte_clear(mm, addr, ptep); 345 return pte; 346 } 347 348 static inline void 349 ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep) 350 { 351 pte_t pte = *ptep; 352 update_pte(ptep, pte_wrprotect(pte)); 353 } 354 355 /* to find an entry in a kernel page-table-directory */ 356 #define pgd_offset_k(address) pgd_offset(&init_mm, address) 357 358 /* to find an entry in a page-table-directory */ 359 #define pgd_offset(mm,address) ((mm)->pgd + pgd_index(address)) 360 361 #define pgd_index(address) ((address) >> PGDIR_SHIFT) 362 363 /* Find an entry in the second-level page table.. */ 364 #define pmd_offset(dir,address) ((pmd_t*)(dir)) 365 366 /* Find an entry in the third-level page table.. */ 367 #define pte_index(address) (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) 368 #define pte_offset_kernel(dir,addr) \ 369 ((pte_t*) pmd_page_vaddr(*(dir)) + pte_index(addr)) 370 #define pte_offset_map(dir,addr) pte_offset_kernel((dir),(addr)) 371 #define pte_unmap(pte) do { } while (0) 372 373 374 /* 375 * Encode and decode a swap and file entry. 376 */ 377 #define SWP_TYPE_BITS 5 378 #define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > SWP_TYPE_BITS) 379 380 #define __swp_type(entry) (((entry).val >> 6) & 0x1f) 381 #define __swp_offset(entry) ((entry).val >> 11) 382 #define __swp_entry(type,offs) \ 383 ((swp_entry_t){((type) << 6) | ((offs) << 11) | \ 384 _PAGE_CA_INVALID | _PAGE_USER}) 385 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) 386 #define __swp_entry_to_pte(x) ((pte_t) { (x).val }) 387 388 #endif /* !defined (__ASSEMBLY__) */ 389 390 391 #ifdef __ASSEMBLY__ 392 393 /* Assembly macro _PGD_INDEX is the same as C pgd_index(unsigned long), 394 * _PGD_OFFSET as C pgd_offset(struct mm_struct*, unsigned long), 395 * _PMD_OFFSET as C pmd_offset(pgd_t*, unsigned long) 396 * _PTE_OFFSET as C pte_offset(pmd_t*, unsigned long) 397 * 398 * Note: We require an additional temporary register which can be the same as 399 * the register that holds the address. 400 * 401 * ((pte_t*) ((unsigned long)(pmd_val(*pmd) & PAGE_MASK)) + pte_index(addr)) 402 * 403 */ 404 #define _PGD_INDEX(rt,rs) extui rt, rs, PGDIR_SHIFT, 32-PGDIR_SHIFT 405 #define _PTE_INDEX(rt,rs) extui rt, rs, PAGE_SHIFT, PTRS_PER_PTE_SHIFT 406 407 #define _PGD_OFFSET(mm,adr,tmp) l32i mm, mm, MM_PGD; \ 408 _PGD_INDEX(tmp, adr); \ 409 addx4 mm, tmp, mm 410 411 #define _PTE_OFFSET(pmd,adr,tmp) _PTE_INDEX(tmp, adr); \ 412 srli pmd, pmd, PAGE_SHIFT; \ 413 slli pmd, pmd, PAGE_SHIFT; \ 414 addx4 pmd, tmp, pmd 415 416 #else 417 418 #define kern_addr_valid(addr) (1) 419 420 extern void update_mmu_cache(struct vm_area_struct * vma, 421 unsigned long address, pte_t *ptep); 422 423 typedef pte_t *pte_addr_t; 424 425 #endif /* !defined (__ASSEMBLY__) */ 426 427 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG 428 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR 429 #define __HAVE_ARCH_PTEP_SET_WRPROTECT 430 #define __HAVE_ARCH_PTEP_MKDIRTY 431 #define __HAVE_ARCH_PTE_SAME 432 /* We provide our own get_unmapped_area to cope with 433 * SHM area cache aliasing for userland. 434 */ 435 #define HAVE_ARCH_UNMAPPED_AREA 436 437 #include <asm-generic/pgtable.h> 438 439 #endif /* _XTENSA_PGTABLE_H */ 440