1 /* 2 * Copyright (C) 2012 Regents of the University of California 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation, version 2. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 */ 13 14 #ifndef _ASM_RISCV_PGTABLE_H 15 #define _ASM_RISCV_PGTABLE_H 16 17 #include <linux/mmzone.h> 18 19 #include <asm/pgtable-bits.h> 20 21 #ifndef __ASSEMBLY__ 22 23 /* Page Upper Directory not used in RISC-V */ 24 #include <asm-generic/pgtable-nopud.h> 25 #include <asm/page.h> 26 #include <asm/tlbflush.h> 27 #include <linux/mm_types.h> 28 29 #ifdef CONFIG_64BIT 30 #include <asm/pgtable-64.h> 31 #else 32 #include <asm/pgtable-32.h> 33 #endif /* CONFIG_64BIT */ 34 35 /* Number of entries in the page global directory */ 36 #define PTRS_PER_PGD (PAGE_SIZE / sizeof(pgd_t)) 37 /* Number of entries in the page table */ 38 #define PTRS_PER_PTE (PAGE_SIZE / sizeof(pte_t)) 39 40 /* Number of PGD entries that a user-mode program can use */ 41 #define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE) 42 #define FIRST_USER_ADDRESS 0 43 44 /* Page protection bits */ 45 #define _PAGE_BASE (_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_USER) 46 47 #define PAGE_NONE __pgprot(_PAGE_PROT_NONE) 48 #define PAGE_READ __pgprot(_PAGE_BASE | _PAGE_READ) 49 #define PAGE_WRITE __pgprot(_PAGE_BASE | _PAGE_READ | _PAGE_WRITE) 50 #define PAGE_EXEC __pgprot(_PAGE_BASE | _PAGE_EXEC) 51 #define PAGE_READ_EXEC __pgprot(_PAGE_BASE | _PAGE_READ | _PAGE_EXEC) 52 #define PAGE_WRITE_EXEC __pgprot(_PAGE_BASE | _PAGE_READ | \ 53 _PAGE_EXEC | _PAGE_WRITE) 54 55 #define PAGE_COPY PAGE_READ 56 #define PAGE_COPY_EXEC PAGE_EXEC 57 #define PAGE_COPY_READ_EXEC PAGE_READ_EXEC 58 #define PAGE_SHARED PAGE_WRITE 59 #define PAGE_SHARED_EXEC PAGE_WRITE_EXEC 60 61 #define _PAGE_KERNEL (_PAGE_READ \ 62 | _PAGE_WRITE \ 63 | _PAGE_PRESENT \ 64 | _PAGE_ACCESSED \ 65 | _PAGE_DIRTY) 66 67 #define PAGE_KERNEL __pgprot(_PAGE_KERNEL) 68 #define PAGE_KERNEL_EXEC __pgprot(_PAGE_KERNEL | _PAGE_EXEC) 69 70 extern pgd_t swapper_pg_dir[]; 71 72 /* MAP_PRIVATE permissions: xwr (copy-on-write) */ 73 #define __P000 PAGE_NONE 74 #define __P001 PAGE_READ 75 #define __P010 PAGE_COPY 76 #define __P011 PAGE_COPY 77 #define __P100 PAGE_EXEC 78 #define __P101 PAGE_READ_EXEC 79 #define __P110 PAGE_COPY_EXEC 80 #define __P111 PAGE_COPY_READ_EXEC 81 82 /* MAP_SHARED permissions: xwr */ 83 #define __S000 PAGE_NONE 84 #define __S001 PAGE_READ 85 #define __S010 PAGE_SHARED 86 #define __S011 PAGE_SHARED 87 #define __S100 PAGE_EXEC 88 #define __S101 PAGE_READ_EXEC 89 #define __S110 PAGE_SHARED_EXEC 90 #define __S111 PAGE_SHARED_EXEC 91 92 /* 93 * ZERO_PAGE is a global shared page that is always zero, 94 * used for zero-mapped memory areas, etc. 95 */ 96 extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]; 97 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page)) 98 99 static inline int pmd_present(pmd_t pmd) 100 { 101 return (pmd_val(pmd) & (_PAGE_PRESENT | _PAGE_PROT_NONE)); 102 } 103 104 static inline int pmd_none(pmd_t pmd) 105 { 106 return (pmd_val(pmd) == 0); 107 } 108 109 static inline int pmd_bad(pmd_t pmd) 110 { 111 return !pmd_present(pmd); 112 } 113 114 static inline void set_pmd(pmd_t *pmdp, pmd_t pmd) 115 { 116 *pmdp = pmd; 117 } 118 119 static inline void pmd_clear(pmd_t *pmdp) 120 { 121 set_pmd(pmdp, __pmd(0)); 122 } 123 124 125 static inline pgd_t pfn_pgd(unsigned long pfn, pgprot_t prot) 126 { 127 return __pgd((pfn << _PAGE_PFN_SHIFT) | pgprot_val(prot)); 128 } 129 130 #define pgd_index(addr) (((addr) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1)) 131 132 /* Locate an entry in the page global directory */ 133 static inline pgd_t *pgd_offset(const struct mm_struct *mm, unsigned long addr) 134 { 135 return mm->pgd + pgd_index(addr); 136 } 137 /* Locate an entry in the kernel page global directory */ 138 #define pgd_offset_k(addr) pgd_offset(&init_mm, (addr)) 139 140 static inline struct page *pmd_page(pmd_t pmd) 141 { 142 return pfn_to_page(pmd_val(pmd) >> _PAGE_PFN_SHIFT); 143 } 144 145 static inline unsigned long pmd_page_vaddr(pmd_t pmd) 146 { 147 return (unsigned long)pfn_to_virt(pmd_val(pmd) >> _PAGE_PFN_SHIFT); 148 } 149 150 /* Yields the page frame number (PFN) of a page table entry */ 151 static inline unsigned long pte_pfn(pte_t pte) 152 { 153 return (pte_val(pte) >> _PAGE_PFN_SHIFT); 154 } 155 156 #define pte_page(x) pfn_to_page(pte_pfn(x)) 157 158 /* Constructs a page table entry */ 159 static inline pte_t pfn_pte(unsigned long pfn, pgprot_t prot) 160 { 161 return __pte((pfn << _PAGE_PFN_SHIFT) | pgprot_val(prot)); 162 } 163 164 static inline pte_t mk_pte(struct page *page, pgprot_t prot) 165 { 166 return pfn_pte(page_to_pfn(page), prot); 167 } 168 169 #define pte_index(addr) (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) 170 171 static inline pte_t *pte_offset_kernel(pmd_t *pmd, unsigned long addr) 172 { 173 return (pte_t *)pmd_page_vaddr(*pmd) + pte_index(addr); 174 } 175 176 #define pte_offset_map(dir, addr) pte_offset_kernel((dir), (addr)) 177 #define pte_unmap(pte) ((void)(pte)) 178 179 static inline int pte_present(pte_t pte) 180 { 181 return (pte_val(pte) & (_PAGE_PRESENT | _PAGE_PROT_NONE)); 182 } 183 184 static inline int pte_none(pte_t pte) 185 { 186 return (pte_val(pte) == 0); 187 } 188 189 static inline int pte_write(pte_t pte) 190 { 191 return pte_val(pte) & _PAGE_WRITE; 192 } 193 194 static inline int pte_exec(pte_t pte) 195 { 196 return pte_val(pte) & _PAGE_EXEC; 197 } 198 199 static inline int pte_huge(pte_t pte) 200 { 201 return pte_present(pte) 202 && (pte_val(pte) & (_PAGE_READ | _PAGE_WRITE | _PAGE_EXEC)); 203 } 204 205 static inline int pte_dirty(pte_t pte) 206 { 207 return pte_val(pte) & _PAGE_DIRTY; 208 } 209 210 static inline int pte_young(pte_t pte) 211 { 212 return pte_val(pte) & _PAGE_ACCESSED; 213 } 214 215 static inline int pte_special(pte_t pte) 216 { 217 return pte_val(pte) & _PAGE_SPECIAL; 218 } 219 220 /* static inline pte_t pte_rdprotect(pte_t pte) */ 221 222 static inline pte_t pte_wrprotect(pte_t pte) 223 { 224 return __pte(pte_val(pte) & ~(_PAGE_WRITE)); 225 } 226 227 /* static inline pte_t pte_mkread(pte_t pte) */ 228 229 static inline pte_t pte_mkwrite(pte_t pte) 230 { 231 return __pte(pte_val(pte) | _PAGE_WRITE); 232 } 233 234 /* static inline pte_t pte_mkexec(pte_t pte) */ 235 236 static inline pte_t pte_mkdirty(pte_t pte) 237 { 238 return __pte(pte_val(pte) | _PAGE_DIRTY); 239 } 240 241 static inline pte_t pte_mkclean(pte_t pte) 242 { 243 return __pte(pte_val(pte) & ~(_PAGE_DIRTY)); 244 } 245 246 static inline pte_t pte_mkyoung(pte_t pte) 247 { 248 return __pte(pte_val(pte) | _PAGE_ACCESSED); 249 } 250 251 static inline pte_t pte_mkold(pte_t pte) 252 { 253 return __pte(pte_val(pte) & ~(_PAGE_ACCESSED)); 254 } 255 256 static inline pte_t pte_mkspecial(pte_t pte) 257 { 258 return __pte(pte_val(pte) | _PAGE_SPECIAL); 259 } 260 261 /* Modify page protection bits */ 262 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) 263 { 264 return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot)); 265 } 266 267 #define pgd_ERROR(e) \ 268 pr_err("%s:%d: bad pgd " PTE_FMT ".\n", __FILE__, __LINE__, pgd_val(e)) 269 270 271 /* Commit new configuration to MMU hardware */ 272 static inline void update_mmu_cache(struct vm_area_struct *vma, 273 unsigned long address, pte_t *ptep) 274 { 275 /* 276 * The kernel assumes that TLBs don't cache invalid entries, but 277 * in RISC-V, SFENCE.VMA specifies an ordering constraint, not a 278 * cache flush; it is necessary even after writing invalid entries. 279 * Relying on flush_tlb_fix_spurious_fault would suffice, but 280 * the extra traps reduce performance. So, eagerly SFENCE.VMA. 281 */ 282 local_flush_tlb_page(address); 283 } 284 285 #define __HAVE_ARCH_PTE_SAME 286 static inline int pte_same(pte_t pte_a, pte_t pte_b) 287 { 288 return pte_val(pte_a) == pte_val(pte_b); 289 } 290 291 /* 292 * Certain architectures need to do special things when PTEs within 293 * a page table are directly modified. Thus, the following hook is 294 * made available. 295 */ 296 static inline void set_pte(pte_t *ptep, pte_t pteval) 297 { 298 *ptep = pteval; 299 } 300 301 void flush_icache_pte(pte_t pte); 302 303 static inline void set_pte_at(struct mm_struct *mm, 304 unsigned long addr, pte_t *ptep, pte_t pteval) 305 { 306 if (pte_present(pteval) && pte_exec(pteval)) 307 flush_icache_pte(pteval); 308 309 set_pte(ptep, pteval); 310 } 311 312 static inline void pte_clear(struct mm_struct *mm, 313 unsigned long addr, pte_t *ptep) 314 { 315 set_pte_at(mm, addr, ptep, __pte(0)); 316 } 317 318 #define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS 319 static inline int ptep_set_access_flags(struct vm_area_struct *vma, 320 unsigned long address, pte_t *ptep, 321 pte_t entry, int dirty) 322 { 323 if (!pte_same(*ptep, entry)) 324 set_pte_at(vma->vm_mm, address, ptep, entry); 325 /* 326 * update_mmu_cache will unconditionally execute, handling both 327 * the case that the PTE changed and the spurious fault case. 328 */ 329 return true; 330 } 331 332 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR 333 static inline pte_t ptep_get_and_clear(struct mm_struct *mm, 334 unsigned long address, pte_t *ptep) 335 { 336 return __pte(atomic_long_xchg((atomic_long_t *)ptep, 0)); 337 } 338 339 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG 340 static inline int ptep_test_and_clear_young(struct vm_area_struct *vma, 341 unsigned long address, 342 pte_t *ptep) 343 { 344 if (!pte_young(*ptep)) 345 return 0; 346 return test_and_clear_bit(_PAGE_ACCESSED_OFFSET, &pte_val(*ptep)); 347 } 348 349 #define __HAVE_ARCH_PTEP_SET_WRPROTECT 350 static inline void ptep_set_wrprotect(struct mm_struct *mm, 351 unsigned long address, pte_t *ptep) 352 { 353 atomic_long_and(~(unsigned long)_PAGE_WRITE, (atomic_long_t *)ptep); 354 } 355 356 #define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH 357 static inline int ptep_clear_flush_young(struct vm_area_struct *vma, 358 unsigned long address, pte_t *ptep) 359 { 360 /* 361 * This comment is borrowed from x86, but applies equally to RISC-V: 362 * 363 * Clearing the accessed bit without a TLB flush 364 * doesn't cause data corruption. [ It could cause incorrect 365 * page aging and the (mistaken) reclaim of hot pages, but the 366 * chance of that should be relatively low. ] 367 * 368 * So as a performance optimization don't flush the TLB when 369 * clearing the accessed bit, it will eventually be flushed by 370 * a context switch or a VM operation anyway. [ In the rare 371 * event of it not getting flushed for a long time the delay 372 * shouldn't really matter because there's no real memory 373 * pressure for swapout to react to. ] 374 */ 375 return ptep_test_and_clear_young(vma, address, ptep); 376 } 377 378 /* 379 * Encode and decode a swap entry 380 * 381 * Format of swap PTE: 382 * bit 0: _PAGE_PRESENT (zero) 383 * bit 1: _PAGE_PROT_NONE (zero) 384 * bits 2 to 6: swap type 385 * bits 7 to XLEN-1: swap offset 386 */ 387 #define __SWP_TYPE_SHIFT 2 388 #define __SWP_TYPE_BITS 5 389 #define __SWP_TYPE_MASK ((1UL << __SWP_TYPE_BITS) - 1) 390 #define __SWP_OFFSET_SHIFT (__SWP_TYPE_BITS + __SWP_TYPE_SHIFT) 391 392 #define MAX_SWAPFILES_CHECK() \ 393 BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > __SWP_TYPE_BITS) 394 395 #define __swp_type(x) (((x).val >> __SWP_TYPE_SHIFT) & __SWP_TYPE_MASK) 396 #define __swp_offset(x) ((x).val >> __SWP_OFFSET_SHIFT) 397 #define __swp_entry(type, offset) ((swp_entry_t) \ 398 { ((type) << __SWP_TYPE_SHIFT) | ((offset) << __SWP_OFFSET_SHIFT) }) 399 400 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) 401 #define __swp_entry_to_pte(x) ((pte_t) { (x).val }) 402 403 #ifdef CONFIG_FLATMEM 404 #define kern_addr_valid(addr) (1) /* FIXME */ 405 #endif 406 407 extern void setup_bootmem(void); 408 extern void paging_init(void); 409 410 static inline void pgtable_cache_init(void) 411 { 412 /* No page table caches to initialize */ 413 } 414 415 #define VMALLOC_SIZE (KERN_VIRT_SIZE >> 1) 416 #define VMALLOC_END (PAGE_OFFSET - 1) 417 #define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE) 418 419 /* 420 * Task size is 0x40000000000 for RV64 or 0xb800000 for RV32. 421 * Note that PGDIR_SIZE must evenly divide TASK_SIZE. 422 */ 423 #ifdef CONFIG_64BIT 424 #define TASK_SIZE (PGDIR_SIZE * PTRS_PER_PGD / 2) 425 #else 426 #define TASK_SIZE VMALLOC_START 427 #endif 428 429 #include <asm-generic/pgtable.h> 430 431 #endif /* !__ASSEMBLY__ */ 432 433 #endif /* _ASM_RISCV_PGTABLE_H */ 434