arch/riscv/include/asm/pgtable.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Copyright (C) 2012 Regents of the University of California
   4  */
   5
   6 #ifndef _ASM_RISCV_PGTABLE_H
   7 #define _ASM_RISCV_PGTABLE_H
   8
   9 #include <linux/mmzone.h>
  10 #include <linux/sizes.h>
  11
  12 #include <asm/pgtable-bits.h>
  13
  14 #ifndef __ASSEMBLY__
  15
  16 /* Page Upper Directory not used in RISC-V */
  17 #include <asm-generic/pgtable-nopud.h>
  18 #include <asm/page.h>
  19 #include <asm/tlbflush.h>
  20 #include <linux/mm_types.h>
  21
  22 #ifdef CONFIG_MMU
  23
  24 #define VMALLOC_SIZE     (KERN_VIRT_SIZE >> 1)
  25 #define VMALLOC_END      (PAGE_OFFSET - 1)
  26 #define VMALLOC_START    (PAGE_OFFSET - VMALLOC_SIZE)
  27
  28 #define BPF_JIT_REGION_SIZE     (SZ_128M)
  29 #define BPF_JIT_REGION_START    (PAGE_OFFSET - BPF_JIT_REGION_SIZE)
  30 #define BPF_JIT_REGION_END      (VMALLOC_END)
  31
  32 /*
  33  * Roughly size the vmemmap space to be large enough to fit enough
  34  * struct pages to map half the virtual address space. Then
  35  * position vmemmap directly below the VMALLOC region.
  36  */
  37 #define VMEMMAP_SHIFT \
  38         (CONFIG_VA_BITS - PAGE_SHIFT - 1 + STRUCT_PAGE_MAX_SHIFT)
  39 #define VMEMMAP_SIZE    BIT(VMEMMAP_SHIFT)
  40 #define VMEMMAP_END     (VMALLOC_START - 1)
  41 #define VMEMMAP_START   (VMALLOC_START - VMEMMAP_SIZE)
  42
  43 /*
  44  * Define vmemmap for pfn_to_page & page_to_pfn calls. Needed if kernel
  45  * is configured with CONFIG_SPARSEMEM_VMEMMAP enabled.
  46  */
  47 #define vmemmap         ((struct page *)VMEMMAP_START)
  48
  49 #define PCI_IO_SIZE      SZ_16M
  50 #define PCI_IO_END       VMEMMAP_START
  51 #define PCI_IO_START     (PCI_IO_END - PCI_IO_SIZE)
  52
  53 #define FIXADDR_TOP      PCI_IO_START
  54 #ifdef CONFIG_64BIT
  55 #define FIXADDR_SIZE     PMD_SIZE
  56 #else
  57 #define FIXADDR_SIZE     PGDIR_SIZE
  58 #endif
  59 #define FIXADDR_START    (FIXADDR_TOP - FIXADDR_SIZE)
  60
  61 #endif
  62
  63 #ifdef CONFIG_64BIT
  64 #include <asm/pgtable-64.h>
  65 #else
  66 #include <asm/pgtable-32.h>
  67 #endif /* CONFIG_64BIT */
  68
  69 #ifdef CONFIG_MMU
  70 /* Number of entries in the page global directory */
  71 #define PTRS_PER_PGD    (PAGE_SIZE / sizeof(pgd_t))
  72 /* Number of entries in the page table */
  73 #define PTRS_PER_PTE    (PAGE_SIZE / sizeof(pte_t))
  74
  75 /* Number of PGD entries that a user-mode program can use */
  76 #define USER_PTRS_PER_PGD   (TASK_SIZE / PGDIR_SIZE)
  77
  78 /* Page protection bits */
  79 #define _PAGE_BASE      (_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_USER)
  80
  81 #define PAGE_NONE               __pgprot(_PAGE_PROT_NONE)
  82 #define PAGE_READ               __pgprot(_PAGE_BASE | _PAGE_READ)
  83 #define PAGE_WRITE              __pgprot(_PAGE_BASE | _PAGE_READ | _PAGE_WRITE)
  84 #define PAGE_EXEC               __pgprot(_PAGE_BASE | _PAGE_EXEC)
  85 #define PAGE_READ_EXEC          __pgprot(_PAGE_BASE | _PAGE_READ | _PAGE_EXEC)
  86 #define PAGE_WRITE_EXEC         __pgprot(_PAGE_BASE | _PAGE_READ |      \
  87                                          _PAGE_EXEC | _PAGE_WRITE)
  88
  89 #define PAGE_COPY               PAGE_READ
  90 #define PAGE_COPY_EXEC          PAGE_EXEC
  91 #define PAGE_COPY_READ_EXEC     PAGE_READ_EXEC
  92 #define PAGE_SHARED             PAGE_WRITE
  93 #define PAGE_SHARED_EXEC        PAGE_WRITE_EXEC
  94
  95 #define _PAGE_KERNEL            (_PAGE_READ \
  96                                 | _PAGE_WRITE \
  97                                 | _PAGE_PRESENT \
  98                                 | _PAGE_ACCESSED \
  99                                 | _PAGE_DIRTY)
 100
 101 #define PAGE_KERNEL             __pgprot(_PAGE_KERNEL)
 102 #define PAGE_KERNEL_EXEC        __pgprot(_PAGE_KERNEL | _PAGE_EXEC)
 103
 104 #define PAGE_TABLE              __pgprot(_PAGE_TABLE)
 105
 106 /*
 107  * The RISC-V ISA doesn't yet specify how to query or modify PMAs, so we can't
 108  * change the properties of memory regions.
 109  */
 110 #define _PAGE_IOREMAP _PAGE_KERNEL
 111
 112 extern pgd_t swapper_pg_dir[];
 113
 114 /* MAP_PRIVATE permissions: xwr (copy-on-write) */
 115 #define __P000  PAGE_NONE
 116 #define __P001  PAGE_READ
 117 #define __P010  PAGE_COPY
 118 #define __P011  PAGE_COPY
 119 #define __P100  PAGE_EXEC
 120 #define __P101  PAGE_READ_EXEC
 121 #define __P110  PAGE_COPY_EXEC
 122 #define __P111  PAGE_COPY_READ_EXEC
 123
 124 /* MAP_SHARED permissions: xwr */
 125 #define __S000  PAGE_NONE
 126 #define __S001  PAGE_READ
 127 #define __S010  PAGE_SHARED
 128 #define __S011  PAGE_SHARED
 129 #define __S100  PAGE_EXEC
 130 #define __S101  PAGE_READ_EXEC
 131 #define __S110  PAGE_SHARED_EXEC
 132 #define __S111  PAGE_SHARED_EXEC
 133
 134 static inline int pmd_present(pmd_t pmd)
 135 {
 136         return (pmd_val(pmd) & (_PAGE_PRESENT | _PAGE_PROT_NONE));
 137 }
 138
 139 static inline int pmd_none(pmd_t pmd)
 140 {
 141         return (pmd_val(pmd) == 0);
 142 }
 143
 144 static inline int pmd_bad(pmd_t pmd)
 145 {
 146         return !pmd_present(pmd);
 147 }
 148
 149 #define pmd_leaf        pmd_leaf
 150 static inline int pmd_leaf(pmd_t pmd)
 151 {
 152         return pmd_present(pmd) &&
 153                (pmd_val(pmd) & (_PAGE_READ | _PAGE_WRITE | _PAGE_EXEC));
 154 }
 155
 156 static inline void set_pmd(pmd_t *pmdp, pmd_t pmd)
 157 {
 158         *pmdp = pmd;
 159 }
 160
 161 static inline void pmd_clear(pmd_t *pmdp)
 162 {
 163         set_pmd(pmdp, __pmd(0));
 164 }
 165
 166 static inline pgd_t pfn_pgd(unsigned long pfn, pgprot_t prot)
 167 {
 168         return __pgd((pfn << _PAGE_PFN_SHIFT) | pgprot_val(prot));
 169 }
 170
 171 static inline unsigned long _pgd_pfn(pgd_t pgd)
 172 {
 173         return pgd_val(pgd) >> _PAGE_PFN_SHIFT;
 174 }
 175
 176 #define pgd_index(addr) (((addr) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
 177
 178 /* Locate an entry in the page global directory */
 179 static inline pgd_t *pgd_offset(const struct mm_struct *mm, unsigned long addr)
 180 {
 181         return mm->pgd + pgd_index(addr);
 182 }
 183 /* Locate an entry in the kernel page global directory */
 184 #define pgd_offset_k(addr)      pgd_offset(&init_mm, (addr))
 185
 186 static inline struct page *pmd_page(pmd_t pmd)
 187 {
 188         return pfn_to_page(pmd_val(pmd) >> _PAGE_PFN_SHIFT);
 189 }
 190
 191 static inline unsigned long pmd_page_vaddr(pmd_t pmd)
 192 {
 193         return (unsigned long)pfn_to_virt(pmd_val(pmd) >> _PAGE_PFN_SHIFT);
 194 }
 195
 196 /* Yields the page frame number (PFN) of a page table entry */
 197 static inline unsigned long pte_pfn(pte_t pte)
 198 {
 199         return (pte_val(pte) >> _PAGE_PFN_SHIFT);
 200 }
 201
 202 #define pte_page(x)     pfn_to_page(pte_pfn(x))
 203
 204 /* Constructs a page table entry */
 205 static inline pte_t pfn_pte(unsigned long pfn, pgprot_t prot)
 206 {
 207         return __pte((pfn << _PAGE_PFN_SHIFT) | pgprot_val(prot));
 208 }
 209
 210 #define mk_pte(page, prot)       pfn_pte(page_to_pfn(page), prot)
 211
 212 #define pte_index(addr) (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 213
 214 static inline pte_t *pte_offset_kernel(pmd_t *pmd, unsigned long addr)
 215 {
 216         return (pte_t *)pmd_page_vaddr(*pmd) + pte_index(addr);
 217 }
 218
 219 #define pte_offset_map(dir, addr)       pte_offset_kernel((dir), (addr))
 220 #define pte_unmap(pte)                  ((void)(pte))
 221
 222 static inline int pte_present(pte_t pte)
 223 {
 224         return (pte_val(pte) & (_PAGE_PRESENT | _PAGE_PROT_NONE));
 225 }
 226
 227 static inline int pte_none(pte_t pte)
 228 {
 229         return (pte_val(pte) == 0);
 230 }
 231
 232 static inline int pte_write(pte_t pte)
 233 {
 234         return pte_val(pte) & _PAGE_WRITE;
 235 }
 236
 237 static inline int pte_exec(pte_t pte)
 238 {
 239         return pte_val(pte) & _PAGE_EXEC;
 240 }
 241
 242 static inline int pte_huge(pte_t pte)
 243 {
 244         return pte_present(pte)
 245                 && (pte_val(pte) & (_PAGE_READ | _PAGE_WRITE | _PAGE_EXEC));
 246 }
 247
 248 static inline int pte_dirty(pte_t pte)
 249 {
 250         return pte_val(pte) & _PAGE_DIRTY;
 251 }
 252
 253 static inline int pte_young(pte_t pte)
 254 {
 255         return pte_val(pte) & _PAGE_ACCESSED;
 256 }
 257
 258 static inline int pte_special(pte_t pte)
 259 {
 260         return pte_val(pte) & _PAGE_SPECIAL;
 261 }
 262
 263 /* static inline pte_t pte_rdprotect(pte_t pte) */
 264
 265 static inline pte_t pte_wrprotect(pte_t pte)
 266 {
 267         return __pte(pte_val(pte) & ~(_PAGE_WRITE));
 268 }
 269
 270 /* static inline pte_t pte_mkread(pte_t pte) */
 271
 272 static inline pte_t pte_mkwrite(pte_t pte)
 273 {
 274         return __pte(pte_val(pte) | _PAGE_WRITE);
 275 }
 276
 277 /* static inline pte_t pte_mkexec(pte_t pte) */
 278
 279 static inline pte_t pte_mkdirty(pte_t pte)
 280 {
 281         return __pte(pte_val(pte) | _PAGE_DIRTY);
 282 }
 283
 284 static inline pte_t pte_mkclean(pte_t pte)
 285 {
 286         return __pte(pte_val(pte) & ~(_PAGE_DIRTY));
 287 }
 288
 289 static inline pte_t pte_mkyoung(pte_t pte)
 290 {
 291         return __pte(pte_val(pte) | _PAGE_ACCESSED);
 292 }
 293
 294 static inline pte_t pte_mkold(pte_t pte)
 295 {
 296         return __pte(pte_val(pte) & ~(_PAGE_ACCESSED));
 297 }
 298
 299 static inline pte_t pte_mkspecial(pte_t pte)
 300 {
 301         return __pte(pte_val(pte) | _PAGE_SPECIAL);
 302 }
 303
 304 static inline pte_t pte_mkhuge(pte_t pte)
 305 {
 306         return pte;
 307 }
 308
 309 /* Modify page protection bits */
 310 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 311 {
 312         return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));
 313 }
 314
 315 #define pgd_ERROR(e) \
 316         pr_err("%s:%d: bad pgd " PTE_FMT ".\n", __FILE__, __LINE__, pgd_val(e))
 317
 318
 319 /* Commit new configuration to MMU hardware */
 320 static inline void update_mmu_cache(struct vm_area_struct *vma,
 321         unsigned long address, pte_t *ptep)
 322 {
 323         /*
 324          * The kernel assumes that TLBs don't cache invalid entries, but
 325          * in RISC-V, SFENCE.VMA specifies an ordering constraint, not a
 326          * cache flush; it is necessary even after writing invalid entries.
 327          * Relying on flush_tlb_fix_spurious_fault would suffice, but
 328          * the extra traps reduce performance.  So, eagerly SFENCE.VMA.
 329          */
 330         local_flush_tlb_page(address);
 331 }
 332
 333 #define __HAVE_ARCH_PTE_SAME
 334 static inline int pte_same(pte_t pte_a, pte_t pte_b)
 335 {
 336         return pte_val(pte_a) == pte_val(pte_b);
 337 }
 338
 339 /*
 340  * Certain architectures need to do special things when PTEs within
 341  * a page table are directly modified.  Thus, the following hook is
 342  * made available.
 343  */
 344 static inline void set_pte(pte_t *ptep, pte_t pteval)
 345 {
 346         *ptep = pteval;
 347 }
 348
 349 void flush_icache_pte(pte_t pte);
 350
 351 static inline void set_pte_at(struct mm_struct *mm,
 352         unsigned long addr, pte_t *ptep, pte_t pteval)
 353 {
 354         if (pte_present(pteval) && pte_exec(pteval))
 355                 flush_icache_pte(pteval);
 356
 357         set_pte(ptep, pteval);
 358 }
 359
 360 static inline void pte_clear(struct mm_struct *mm,
 361         unsigned long addr, pte_t *ptep)
 362 {
 363         set_pte_at(mm, addr, ptep, __pte(0));
 364 }
 365
 366 #define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
 367 static inline int ptep_set_access_flags(struct vm_area_struct *vma,
 368                                         unsigned long address, pte_t *ptep,
 369                                         pte_t entry, int dirty)
 370 {
 371         if (!pte_same(*ptep, entry))
 372                 set_pte_at(vma->vm_mm, address, ptep, entry);
 373         /*
 374          * update_mmu_cache will unconditionally execute, handling both
 375          * the case that the PTE changed and the spurious fault case.
 376          */
 377         return true;
 378 }
 379
 380 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
 381 static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
 382                                        unsigned long address, pte_t *ptep)
 383 {
 384         return __pte(atomic_long_xchg((atomic_long_t *)ptep, 0));
 385 }
 386
 387 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
 388 static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
 389                                             unsigned long address,
 390                                             pte_t *ptep)
 391 {
 392         if (!pte_young(*ptep))
 393                 return 0;
 394         return test_and_clear_bit(_PAGE_ACCESSED_OFFSET, &pte_val(*ptep));
 395 }
 396
 397 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
 398 static inline void ptep_set_wrprotect(struct mm_struct *mm,
 399                                       unsigned long address, pte_t *ptep)
 400 {
 401         atomic_long_and(~(unsigned long)_PAGE_WRITE, (atomic_long_t *)ptep);
 402 }
 403
 404 #define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
 405 static inline int ptep_clear_flush_young(struct vm_area_struct *vma,
 406                                          unsigned long address, pte_t *ptep)
 407 {
 408         /*
 409          * This comment is borrowed from x86, but applies equally to RISC-V:
 410          *
 411          * Clearing the accessed bit without a TLB flush
 412          * doesn't cause data corruption. [ It could cause incorrect
 413          * page aging and the (mistaken) reclaim of hot pages, but the
 414          * chance of that should be relatively low. ]
 415          *
 416          * So as a performance optimization don't flush the TLB when
 417          * clearing the accessed bit, it will eventually be flushed by
 418          * a context switch or a VM operation anyway. [ In the rare
 419          * event of it not getting flushed for a long time the delay
 420          * shouldn't really matter because there's no real memory
 421          * pressure for swapout to react to. ]
 422          */
 423         return ptep_test_and_clear_young(vma, address, ptep);
 424 }
 425
 426 /*
 427  * Encode and decode a swap entry
 428  *
 429  * Format of swap PTE:
 430  *      bit            0:       _PAGE_PRESENT (zero)
 431  *      bit            1:       _PAGE_PROT_NONE (zero)
 432  *      bits      2 to 6:       swap type
 433  *      bits 7 to XLEN-1:       swap offset
 434  */
 435 #define __SWP_TYPE_SHIFT        2
 436 #define __SWP_TYPE_BITS         5
 437 #define __SWP_TYPE_MASK         ((1UL << __SWP_TYPE_BITS) - 1)
 438 #define __SWP_OFFSET_SHIFT      (__SWP_TYPE_BITS + __SWP_TYPE_SHIFT)
 439
 440 #define MAX_SWAPFILES_CHECK()   \
 441         BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > __SWP_TYPE_BITS)
 442
 443 #define __swp_type(x)   (((x).val >> __SWP_TYPE_SHIFT) & __SWP_TYPE_MASK)
 444 #define __swp_offset(x) ((x).val >> __SWP_OFFSET_SHIFT)
 445 #define __swp_entry(type, offset) ((swp_entry_t) \
 446         { ((type) << __SWP_TYPE_SHIFT) | ((offset) << __SWP_OFFSET_SHIFT) })
 447
 448 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
 449 #define __swp_entry_to_pte(x)   ((pte_t) { (x).val })
 450
 451 /*
 452  * In the RV64 Linux scheme, we give the user half of the virtual-address space
 453  * and give the kernel the other (upper) half.
 454  */
 455 #ifdef CONFIG_64BIT
 456 #define KERN_VIRT_START (-(BIT(CONFIG_VA_BITS)) + TASK_SIZE)
 457 #else
 458 #define KERN_VIRT_START FIXADDR_START
 459 #endif
 460
 461 /*
 462  * Task size is 0x4000000000 for RV64 or 0x9fc00000 for RV32.
 463  * Note that PGDIR_SIZE must evenly divide TASK_SIZE.
 464  */
 465 #ifdef CONFIG_64BIT
 466 #define TASK_SIZE (PGDIR_SIZE * PTRS_PER_PGD / 2)
 467 #else
 468 #define TASK_SIZE FIXADDR_START
 469 #endif
 470
 471 #else /* CONFIG_MMU */
 472
 473 #define PAGE_SHARED             __pgprot(0)
 474 #define PAGE_KERNEL             __pgprot(0)
 475 #define swapper_pg_dir          NULL
 476 #define VMALLOC_START           0
 477
 478 #define TASK_SIZE 0xffffffffUL
 479
 480 static inline void __kernel_map_pages(struct page *page, int numpages, int enable) {}
 481
 482 #endif /* !CONFIG_MMU */
 483
 484 #define kern_addr_valid(addr)   (1) /* FIXME */
 485
 486 extern void *dtb_early_va;
 487 void setup_bootmem(void);
 488 void paging_init(void);
 489
 490 #define FIRST_USER_ADDRESS  0
 491
 492 /*
 493  * ZERO_PAGE is a global shared page that is always zero,
 494  * used for zero-mapped memory areas, etc.
 495  */
 496 extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
 497 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
 498
 499 #include <asm-generic/pgtable.h>
 500
 501 #endif /* !__ASSEMBLY__ */
 502
 503 #endif /* _ASM_RISCV_PGTABLE_H */