1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * include/asm-xtensa/pgtable.h 4 * 5 * Copyright (C) 2001 - 2013 Tensilica Inc. 6 */ 7 8 #ifndef _XTENSA_PGTABLE_H 9 #define _XTENSA_PGTABLE_H 10 11 #include <asm/page.h> 12 #include <asm/kmem_layout.h> 13 #include <asm-generic/pgtable-nopmd.h> 14 15 /* 16 * We only use two ring levels, user and kernel space. 17 */ 18 19 #ifdef CONFIG_MMU 20 #define USER_RING 1 /* user ring level */ 21 #else 22 #define USER_RING 0 23 #endif 24 #define KERNEL_RING 0 /* kernel ring level */ 25 26 /* 27 * The Xtensa architecture port of Linux has a two-level page table system, 28 * i.e. the logical three-level Linux page table layout is folded. 29 * Each task has the following memory page tables: 30 * 31 * PGD table (page directory), ie. 3rd-level page table: 32 * One page (4 kB) of 1024 (PTRS_PER_PGD) pointers to PTE tables 33 * (Architectures that don't have the PMD folded point to the PMD tables) 34 * 35 * The pointer to the PGD table for a given task can be retrieved from 36 * the task structure (struct task_struct*) t, e.g. current(): 37 * (t->mm ? t->mm : t->active_mm)->pgd 38 * 39 * PMD tables (page middle-directory), ie. 2nd-level page tables: 40 * Absent for the Xtensa architecture (folded, PTRS_PER_PMD == 1). 41 * 42 * PTE tables (page table entry), ie. 1st-level page tables: 43 * One page (4 kB) of 1024 (PTRS_PER_PTE) PTEs with a special PTE 44 * invalid_pte_table for absent mappings. 45 * 46 * The individual pages are 4 kB big with special pages for the empty_zero_page. 47 */ 48 49 #define PGDIR_SHIFT 22 50 #define PGDIR_SIZE (1UL << PGDIR_SHIFT) 51 #define PGDIR_MASK (~(PGDIR_SIZE-1)) 52 53 /* 54 * Entries per page directory level: we use two-level, so 55 * we don't really have any PMD directory physically. 56 */ 57 #define PTRS_PER_PTE 1024 58 #define PTRS_PER_PTE_SHIFT 10 59 #define PTRS_PER_PGD 1024 60 #define PGD_ORDER 0 61 #define USER_PTRS_PER_PGD (TASK_SIZE/PGDIR_SIZE) 62 #define FIRST_USER_ADDRESS 0UL 63 #define FIRST_USER_PGD_NR (FIRST_USER_ADDRESS >> PGDIR_SHIFT) 64 65 #ifdef CONFIG_MMU 66 /* 67 * Virtual memory area. We keep a distance to other memory regions to be 68 * on the safe side. We also use this area for cache aliasing. 69 */ 70 #define VMALLOC_START (XCHAL_KSEG_CACHED_VADDR - 0x10000000) 71 #define VMALLOC_END (VMALLOC_START + 0x07FEFFFF) 72 #define TLBTEMP_BASE_1 (VMALLOC_START + 0x08000000) 73 #define TLBTEMP_BASE_2 (TLBTEMP_BASE_1 + DCACHE_WAY_SIZE) 74 #if 2 * DCACHE_WAY_SIZE > ICACHE_WAY_SIZE 75 #define TLBTEMP_SIZE (2 * DCACHE_WAY_SIZE) 76 #else 77 #define TLBTEMP_SIZE ICACHE_WAY_SIZE 78 #endif 79 80 #else 81 82 #define VMALLOC_START __XTENSA_UL_CONST(0) 83 #define VMALLOC_END __XTENSA_UL_CONST(0xffffffff) 84 85 #endif 86 87 /* 88 * For the Xtensa architecture, the PTE layout is as follows: 89 * 90 * 31------12 11 10-9 8-6 5-4 3-2 1-0 91 * +-----------------------------------------+ 92 * | | Software | HARDWARE | 93 * | PPN | ADW | RI |Attribute| 94 * +-----------------------------------------+ 95 * pte_none | MBZ | 01 | 11 | 00 | 96 * +-----------------------------------------+ 97 * present | PPN | 0 | 00 | ADW | RI | CA | wx | 98 * +- - - - - - - - - - - - - - - - - - - - -+ 99 * (PAGE_NONE)| PPN | 0 | 00 | ADW | 01 | 11 | 11 | 100 * +-----------------------------------------+ 101 * swap | index | type | 01 | 11 | 00 | 102 * +-----------------------------------------+ 103 * 104 * For T1050 hardware and earlier the layout differs for present and (PAGE_NONE) 105 * +-----------------------------------------+ 106 * present | PPN | 0 | 00 | ADW | RI | CA | w1 | 107 * +-----------------------------------------+ 108 * (PAGE_NONE)| PPN | 0 | 00 | ADW | 01 | 01 | 00 | 109 * +-----------------------------------------+ 110 * 111 * Legend: 112 * PPN Physical Page Number 113 * ADW software: accessed (young) / dirty / writable 114 * RI ring (0=privileged, 1=user, 2 and 3 are unused) 115 * CA cache attribute: 00 bypass, 01 writeback, 10 writethrough 116 * (11 is invalid and used to mark pages that are not present) 117 * w page is writable (hw) 118 * x page is executable (hw) 119 * index swap offset / PAGE_SIZE (bit 11-31: 21 bits -> 8 GB) 120 * (note that the index is always non-zero) 121 * type swap type (5 bits -> 32 types) 122 * 123 * Notes: 124 * - (PROT_NONE) is a special case of 'present' but causes an exception for 125 * any access (read, write, and execute). 126 * - 'multihit-exception' has the highest priority of all MMU exceptions, 127 * so the ring must be set to 'RING_USER' even for 'non-present' pages. 128 * - on older hardware, the exectuable flag was not supported and 129 * used as a 'valid' flag, so it needs to be always set. 130 * - we need to keep track of certain flags in software (dirty and young) 131 * to do this, we use write exceptions and have a separate software w-flag. 132 * - attribute value 1101 (and 1111 on T1050 and earlier) is reserved 133 */ 134 135 #define _PAGE_ATTRIB_MASK 0xf 136 137 #define _PAGE_HW_EXEC (1<<0) /* hardware: page is executable */ 138 #define _PAGE_HW_WRITE (1<<1) /* hardware: page is writable */ 139 140 #define _PAGE_CA_BYPASS (0<<2) /* bypass, non-speculative */ 141 #define _PAGE_CA_WB (1<<2) /* write-back */ 142 #define _PAGE_CA_WT (2<<2) /* write-through */ 143 #define _PAGE_CA_MASK (3<<2) 144 #define _PAGE_CA_INVALID (3<<2) 145 146 /* We use invalid attribute values to distinguish special pte entries */ 147 #if XCHAL_HW_VERSION_MAJOR < 2000 148 #define _PAGE_HW_VALID 0x01 /* older HW needed this bit set */ 149 #define _PAGE_NONE 0x04 150 #else 151 #define _PAGE_HW_VALID 0x00 152 #define _PAGE_NONE 0x0f 153 #endif 154 155 #define _PAGE_USER (1<<4) /* user access (ring=1) */ 156 157 /* Software */ 158 #define _PAGE_WRITABLE_BIT 6 159 #define _PAGE_WRITABLE (1<<6) /* software: page writable */ 160 #define _PAGE_DIRTY (1<<7) /* software: page dirty */ 161 #define _PAGE_ACCESSED (1<<8) /* software: page accessed (read) */ 162 163 #ifdef CONFIG_MMU 164 165 #define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY) 166 #define _PAGE_PRESENT (_PAGE_HW_VALID | _PAGE_CA_WB | _PAGE_ACCESSED) 167 168 #define PAGE_NONE __pgprot(_PAGE_NONE | _PAGE_USER) 169 #define PAGE_COPY __pgprot(_PAGE_PRESENT | _PAGE_USER) 170 #define PAGE_COPY_EXEC __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_HW_EXEC) 171 #define PAGE_READONLY __pgprot(_PAGE_PRESENT | _PAGE_USER) 172 #define PAGE_READONLY_EXEC __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_HW_EXEC) 173 #define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_WRITABLE) 174 #define PAGE_SHARED_EXEC \ 175 __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_WRITABLE | _PAGE_HW_EXEC) 176 #define PAGE_KERNEL __pgprot(_PAGE_PRESENT | _PAGE_HW_WRITE) 177 #define PAGE_KERNEL_RO __pgprot(_PAGE_PRESENT) 178 #define PAGE_KERNEL_EXEC __pgprot(_PAGE_PRESENT|_PAGE_HW_WRITE|_PAGE_HW_EXEC) 179 180 #if (DCACHE_WAY_SIZE > PAGE_SIZE) 181 # define _PAGE_DIRECTORY (_PAGE_HW_VALID | _PAGE_ACCESSED | _PAGE_CA_BYPASS) 182 #else 183 # define _PAGE_DIRECTORY (_PAGE_HW_VALID | _PAGE_ACCESSED | _PAGE_CA_WB) 184 #endif 185 186 #else /* no mmu */ 187 188 # define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY) 189 # define PAGE_NONE __pgprot(0) 190 # define PAGE_SHARED __pgprot(0) 191 # define PAGE_COPY __pgprot(0) 192 # define PAGE_READONLY __pgprot(0) 193 # define PAGE_KERNEL __pgprot(0) 194 195 #endif 196 197 /* 198 * On certain configurations of Xtensa MMUs (eg. the initial Linux config), 199 * the MMU can't do page protection for execute, and considers that the same as 200 * read. Also, write permissions may imply read permissions. 201 * What follows is the closest we can get by reasonable means.. 202 * See linux/mm/mmap.c for protection_map[] array that uses these definitions. 203 */ 204 #define __P000 PAGE_NONE /* private --- */ 205 #define __P001 PAGE_READONLY /* private --r */ 206 #define __P010 PAGE_COPY /* private -w- */ 207 #define __P011 PAGE_COPY /* private -wr */ 208 #define __P100 PAGE_READONLY_EXEC /* private x-- */ 209 #define __P101 PAGE_READONLY_EXEC /* private x-r */ 210 #define __P110 PAGE_COPY_EXEC /* private xw- */ 211 #define __P111 PAGE_COPY_EXEC /* private xwr */ 212 213 #define __S000 PAGE_NONE /* shared --- */ 214 #define __S001 PAGE_READONLY /* shared --r */ 215 #define __S010 PAGE_SHARED /* shared -w- */ 216 #define __S011 PAGE_SHARED /* shared -wr */ 217 #define __S100 PAGE_READONLY_EXEC /* shared x-- */ 218 #define __S101 PAGE_READONLY_EXEC /* shared x-r */ 219 #define __S110 PAGE_SHARED_EXEC /* shared xw- */ 220 #define __S111 PAGE_SHARED_EXEC /* shared xwr */ 221 222 #ifndef __ASSEMBLY__ 223 224 #define pte_ERROR(e) \ 225 printk("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e)) 226 #define pgd_ERROR(e) \ 227 printk("%s:%d: bad pgd entry %08lx.\n", __FILE__, __LINE__, pgd_val(e)) 228 229 extern unsigned long empty_zero_page[1024]; 230 231 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page)) 232 233 #ifdef CONFIG_MMU 234 extern pgd_t swapper_pg_dir[PAGE_SIZE/sizeof(pgd_t)]; 235 extern void paging_init(void); 236 #else 237 # define swapper_pg_dir NULL 238 static inline void paging_init(void) { } 239 #endif 240 241 /* 242 * The pmd contains the kernel virtual address of the pte page. 243 */ 244 #define pmd_page_vaddr(pmd) ((unsigned long)(pmd_val(pmd) & PAGE_MASK)) 245 #define pmd_page(pmd) virt_to_page(pmd_val(pmd)) 246 247 /* 248 * pte status. 249 */ 250 # define pte_none(pte) (pte_val(pte) == (_PAGE_CA_INVALID | _PAGE_USER)) 251 #if XCHAL_HW_VERSION_MAJOR < 2000 252 # define pte_present(pte) ((pte_val(pte) & _PAGE_CA_MASK) != _PAGE_CA_INVALID) 253 #else 254 # define pte_present(pte) \ 255 (((pte_val(pte) & _PAGE_CA_MASK) != _PAGE_CA_INVALID) \ 256 || ((pte_val(pte) & _PAGE_ATTRIB_MASK) == _PAGE_NONE)) 257 #endif 258 #define pte_clear(mm,addr,ptep) \ 259 do { update_pte(ptep, __pte(_PAGE_CA_INVALID | _PAGE_USER)); } while (0) 260 261 #define pmd_none(pmd) (!pmd_val(pmd)) 262 #define pmd_present(pmd) (pmd_val(pmd) & PAGE_MASK) 263 #define pmd_bad(pmd) (pmd_val(pmd) & ~PAGE_MASK) 264 #define pmd_clear(pmdp) do { set_pmd(pmdp, __pmd(0)); } while (0) 265 266 static inline int pte_write(pte_t pte) { return pte_val(pte) & _PAGE_WRITABLE; } 267 static inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; } 268 static inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; } 269 270 static inline pte_t pte_wrprotect(pte_t pte) 271 { pte_val(pte) &= ~(_PAGE_WRITABLE | _PAGE_HW_WRITE); return pte; } 272 static inline pte_t pte_mkclean(pte_t pte) 273 { pte_val(pte) &= ~(_PAGE_DIRTY | _PAGE_HW_WRITE); return pte; } 274 static inline pte_t pte_mkold(pte_t pte) 275 { pte_val(pte) &= ~_PAGE_ACCESSED; return pte; } 276 static inline pte_t pte_mkdirty(pte_t pte) 277 { pte_val(pte) |= _PAGE_DIRTY; return pte; } 278 static inline pte_t pte_mkyoung(pte_t pte) 279 { pte_val(pte) |= _PAGE_ACCESSED; return pte; } 280 static inline pte_t pte_mkwrite(pte_t pte) 281 { pte_val(pte) |= _PAGE_WRITABLE; return pte; } 282 283 #define pgprot_noncached(prot) \ 284 ((__pgprot((pgprot_val(prot) & ~_PAGE_CA_MASK) | \ 285 _PAGE_CA_BYPASS))) 286 287 /* 288 * Conversion functions: convert a page and protection to a page entry, 289 * and a page entry and page directory to the page they refer to. 290 */ 291 292 #define pte_pfn(pte) (pte_val(pte) >> PAGE_SHIFT) 293 #define pte_same(a,b) (pte_val(a) == pte_val(b)) 294 #define pte_page(x) pfn_to_page(pte_pfn(x)) 295 #define pfn_pte(pfn, prot) __pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot)) 296 #define mk_pte(page, prot) pfn_pte(page_to_pfn(page), prot) 297 298 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) 299 { 300 return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot)); 301 } 302 303 /* 304 * Certain architectures need to do special things when pte's 305 * within a page table are directly modified. Thus, the following 306 * hook is made available. 307 */ 308 static inline void update_pte(pte_t *ptep, pte_t pteval) 309 { 310 *ptep = pteval; 311 #if (DCACHE_WAY_SIZE > PAGE_SIZE) && XCHAL_DCACHE_IS_WRITEBACK 312 __asm__ __volatile__ ("dhwb %0, 0" :: "a" (ptep)); 313 #endif 314 315 } 316 317 struct mm_struct; 318 319 static inline void 320 set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pteval) 321 { 322 update_pte(ptep, pteval); 323 } 324 325 static inline void set_pte(pte_t *ptep, pte_t pteval) 326 { 327 update_pte(ptep, pteval); 328 } 329 330 static inline void 331 set_pmd(pmd_t *pmdp, pmd_t pmdval) 332 { 333 *pmdp = pmdval; 334 } 335 336 struct vm_area_struct; 337 338 static inline int 339 ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr, 340 pte_t *ptep) 341 { 342 pte_t pte = *ptep; 343 if (!pte_young(pte)) 344 return 0; 345 update_pte(ptep, pte_mkold(pte)); 346 return 1; 347 } 348 349 static inline pte_t 350 ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) 351 { 352 pte_t pte = *ptep; 353 pte_clear(mm, addr, ptep); 354 return pte; 355 } 356 357 static inline void 358 ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep) 359 { 360 pte_t pte = *ptep; 361 update_pte(ptep, pte_wrprotect(pte)); 362 } 363 364 /* 365 * Encode and decode a swap and file entry. 366 */ 367 #define SWP_TYPE_BITS 5 368 #define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > SWP_TYPE_BITS) 369 370 #define __swp_type(entry) (((entry).val >> 6) & 0x1f) 371 #define __swp_offset(entry) ((entry).val >> 11) 372 #define __swp_entry(type,offs) \ 373 ((swp_entry_t){((type) << 6) | ((offs) << 11) | \ 374 _PAGE_CA_INVALID | _PAGE_USER}) 375 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) 376 #define __swp_entry_to_pte(x) ((pte_t) { (x).val }) 377 378 #endif /* !defined (__ASSEMBLY__) */ 379 380 381 #ifdef __ASSEMBLY__ 382 383 /* Assembly macro _PGD_INDEX is the same as C pgd_index(unsigned long), 384 * _PGD_OFFSET as C pgd_offset(struct mm_struct*, unsigned long), 385 * _PMD_OFFSET as C pmd_offset(pgd_t*, unsigned long) 386 * _PTE_OFFSET as C pte_offset(pmd_t*, unsigned long) 387 * 388 * Note: We require an additional temporary register which can be the same as 389 * the register that holds the address. 390 * 391 * ((pte_t*) ((unsigned long)(pmd_val(*pmd) & PAGE_MASK)) + pte_index(addr)) 392 * 393 */ 394 #define _PGD_INDEX(rt,rs) extui rt, rs, PGDIR_SHIFT, 32-PGDIR_SHIFT 395 #define _PTE_INDEX(rt,rs) extui rt, rs, PAGE_SHIFT, PTRS_PER_PTE_SHIFT 396 397 #define _PGD_OFFSET(mm,adr,tmp) l32i mm, mm, MM_PGD; \ 398 _PGD_INDEX(tmp, adr); \ 399 addx4 mm, tmp, mm 400 401 #define _PTE_OFFSET(pmd,adr,tmp) _PTE_INDEX(tmp, adr); \ 402 srli pmd, pmd, PAGE_SHIFT; \ 403 slli pmd, pmd, PAGE_SHIFT; \ 404 addx4 pmd, tmp, pmd 405 406 #else 407 408 #define kern_addr_valid(addr) (1) 409 410 extern void update_mmu_cache(struct vm_area_struct * vma, 411 unsigned long address, pte_t *ptep); 412 413 typedef pte_t *pte_addr_t; 414 415 #endif /* !defined (__ASSEMBLY__) */ 416 417 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG 418 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR 419 #define __HAVE_ARCH_PTEP_SET_WRPROTECT 420 #define __HAVE_ARCH_PTEP_MKDIRTY 421 #define __HAVE_ARCH_PTE_SAME 422 /* We provide our own get_unmapped_area to cope with 423 * SHM area cache aliasing for userland. 424 */ 425 #define HAVE_ARCH_UNMAPPED_AREA 426 427 #endif /* _XTENSA_PGTABLE_H */ 428