arch/hexagon/include/asm/pgtable.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Page table support for the Hexagon architecture
   4  *
   5  * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
   6  */
   7
   8 #ifndef _ASM_PGTABLE_H
   9 #define _ASM_PGTABLE_H
  10
  11 /*
  12  * Page table definitions for Qualcomm Hexagon processor.
  13  */
  14 #include <asm/page.h>
  15 #define __ARCH_USE_5LEVEL_HACK
  16 #include <asm-generic/pgtable-nopmd.h>
  17
  18 /* A handy thing to have if one has the RAM. Declared in head.S */
  19 extern unsigned long empty_zero_page;
  20
  21 /*
  22  * The PTE model described here is that of the Hexagon Virtual Machine,
  23  * which autonomously walks 2-level page tables.  At a lower level, we
  24  * also describe the RISCish software-loaded TLB entry structure of
  25  * the underlying Hexagon processor. A kernel built to run on the
  26  * virtual machine has no need to know about the underlying hardware.
  27  */
  28 #include <asm/vm_mmu.h>
  29
  30 /*
  31  * To maximize the comfort level for the PTE manipulation macros,
  32  * define the "well known" architecture-specific bits.
  33  */
  34 #define _PAGE_READ      __HVM_PTE_R
  35 #define _PAGE_WRITE     __HVM_PTE_W
  36 #define _PAGE_EXECUTE   __HVM_PTE_X
  37 #define _PAGE_USER      __HVM_PTE_U
  38
  39 /*
  40  * We have a total of 4 "soft" bits available in the abstract PTE.
  41  * The two mandatory software bits are Dirty and Accessed.
  42  * To make nonlinear swap work according to the more recent
  43  * model, we want a low order "Present" bit to indicate whether
  44  * the PTE describes MMU programming or swap space.
  45  */
  46 #define _PAGE_PRESENT   (1<<0)
  47 #define _PAGE_DIRTY     (1<<1)
  48 #define _PAGE_ACCESSED  (1<<2)
  49
  50 /*
  51  * For now, let's say that Valid and Present are the same thing.
  52  * Alternatively, we could say that it's the "or" of R, W, and X
  53  * permissions.
  54  */
  55 #define _PAGE_VALID     _PAGE_PRESENT
  56
  57 /*
  58  * We're not defining _PAGE_GLOBAL here, since there's no concept
  59  * of global pages or ASIDs exposed to the Hexagon Virtual Machine,
  60  * and we want to use the same page table structures and macros in
  61  * the native kernel as we do in the virtual machine kernel.
  62  * So we'll put up with a bit of inefficiency for now...
  63  */
  64
  65 /*
  66  * Top "FOURTH" level (pgd), which for the Hexagon VM is really
  67  * only the second from the bottom, pgd and pud both being collapsed.
  68  * Each entry represents 4MB of virtual address space, 4K of table
  69  * thus maps the full 4GB.
  70  */
  71 #define PGDIR_SHIFT 22
  72 #define PTRS_PER_PGD 1024
  73
  74 #define PGDIR_SIZE (1UL << PGDIR_SHIFT)
  75 #define PGDIR_MASK (~(PGDIR_SIZE-1))
  76
  77 #ifdef CONFIG_PAGE_SIZE_4KB
  78 #define PTRS_PER_PTE 1024
  79 #endif
  80
  81 #ifdef CONFIG_PAGE_SIZE_16KB
  82 #define PTRS_PER_PTE 256
  83 #endif
  84
  85 #ifdef CONFIG_PAGE_SIZE_64KB
  86 #define PTRS_PER_PTE 64
  87 #endif
  88
  89 #ifdef CONFIG_PAGE_SIZE_256KB
  90 #define PTRS_PER_PTE 16
  91 #endif
  92
  93 #ifdef CONFIG_PAGE_SIZE_1MB
  94 #define PTRS_PER_PTE 4
  95 #endif
  96
  97 /*  Any bigger and the PTE disappears.  */
  98 #define pgd_ERROR(e) \
  99         printk(KERN_ERR "%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__,\
 100                 pgd_val(e))
 101
 102 /*
 103  * Page Protection Constants. Includes (in this variant) cache attributes.
 104  */
 105 extern unsigned long _dflt_cache_att;
 106
 107 #define PAGE_NONE       __pgprot(_PAGE_PRESENT | _PAGE_USER | \
 108                                 _dflt_cache_att)
 109 #define PAGE_READONLY   __pgprot(_PAGE_PRESENT | _PAGE_USER | \
 110                                 _PAGE_READ | _PAGE_EXECUTE | _dflt_cache_att)
 111 #define PAGE_COPY       PAGE_READONLY
 112 #define PAGE_EXEC       __pgprot(_PAGE_PRESENT | _PAGE_USER | \
 113                                 _PAGE_READ | _PAGE_EXECUTE | _dflt_cache_att)
 114 #define PAGE_COPY_EXEC  PAGE_EXEC
 115 #define PAGE_SHARED     __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_READ | \
 116                                 _PAGE_EXECUTE | _PAGE_WRITE | _dflt_cache_att)
 117 #define PAGE_KERNEL     __pgprot(_PAGE_PRESENT | _PAGE_READ | \
 118                                 _PAGE_WRITE | _PAGE_EXECUTE | _dflt_cache_att)
 119
 120
 121 /*
 122  * Aliases for mapping mmap() protection bits to page protections.
 123  * These get used for static initialization, so using the _dflt_cache_att
 124  * variable for the default cache attribute isn't workable. If the
 125  * default gets changed at boot time, the boot option code has to
 126  * update data structures like the protaction_map[] array.
 127  */
 128 #define CACHEDEF        (CACHE_DEFAULT << 6)
 129
 130 /* Private (copy-on-write) page protections. */
 131 #define __P000 __pgprot(_PAGE_PRESENT | _PAGE_USER | CACHEDEF)
 132 #define __P001 __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_READ | CACHEDEF)
 133 #define __P010 __P000   /* Write-only copy-on-write */
 134 #define __P011 __P001   /* Read/Write copy-on-write */
 135 #define __P100 __pgprot(_PAGE_PRESENT | _PAGE_USER | \
 136                         _PAGE_EXECUTE | CACHEDEF)
 137 #define __P101 __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_EXECUTE | \
 138                         _PAGE_READ | CACHEDEF)
 139 #define __P110 __P100   /* Write/execute copy-on-write */
 140 #define __P111 __P101   /* Read/Write/Execute, copy-on-write */
 141
 142 /* Shared page protections. */
 143 #define __S000 __P000
 144 #define __S001 __P001
 145 #define __S010 __pgprot(_PAGE_PRESENT | _PAGE_USER | \
 146                         _PAGE_WRITE | CACHEDEF)
 147 #define __S011 __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_READ | \
 148                         _PAGE_WRITE | CACHEDEF)
 149 #define __S100 __pgprot(_PAGE_PRESENT | _PAGE_USER | \
 150                         _PAGE_EXECUTE | CACHEDEF)
 151 #define __S101 __P101
 152 #define __S110 __pgprot(_PAGE_PRESENT | _PAGE_USER | \
 153                         _PAGE_EXECUTE | _PAGE_WRITE | CACHEDEF)
 154 #define __S111 __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_READ | \
 155                         _PAGE_EXECUTE | _PAGE_WRITE | CACHEDEF)
 156
 157 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];  /* located in head.S */
 158
 159 /* Seems to be zero even in architectures where the zero page is firewalled? */
 160 #define FIRST_USER_ADDRESS 0UL
 161 #define pte_special(pte)        0
 162 #define pte_mkspecial(pte)      (pte)
 163
 164 /*  HUGETLB not working currently  */
 165 #ifdef CONFIG_HUGETLB_PAGE
 166 #define pte_mkhuge(pte) __pte((pte_val(pte) & ~0x3) | HVM_HUGEPAGE_SIZE)
 167 #endif
 168
 169 /*
 170  * For now, assume that higher-level code will do TLB/MMU invalidations
 171  * and don't insert that overhead into this low-level function.
 172  */
 173 extern void sync_icache_dcache(pte_t pte);
 174
 175 #define pte_present_exec_user(pte) \
 176         ((pte_val(pte) & (_PAGE_EXECUTE | _PAGE_USER)) == \
 177         (_PAGE_EXECUTE | _PAGE_USER))
 178
 179 static inline void set_pte(pte_t *ptep, pte_t pteval)
 180 {
 181         /*  should really be using pte_exec, if it weren't declared later. */
 182         if (pte_present_exec_user(pteval))
 183                 sync_icache_dcache(pteval);
 184
 185         *ptep = pteval;
 186 }
 187
 188 /*
 189  * For the Hexagon Virtual Machine MMU (or its emulation), a null/invalid
 190  * L1 PTE (PMD/PGD) has 7 in the least significant bits. For the L2 PTE
 191  * (Linux PTE), the key is to have bits 11..9 all zero.  We'd use 0x7
 192  * as a universal null entry, but some of those least significant bits
 193  * are interpreted by software.
 194  */
 195 #define _NULL_PMD       0x7
 196 #define _NULL_PTE       0x0
 197
 198 static inline void pmd_clear(pmd_t *pmd_entry_ptr)
 199 {
 200          pmd_val(*pmd_entry_ptr) = _NULL_PMD;
 201 }
 202
 203 /*
 204  * Conveniently, a null PTE value is invalid.
 205  */
 206 static inline void pte_clear(struct mm_struct *mm, unsigned long addr,
 207                                 pte_t *ptep)
 208 {
 209         pte_val(*ptep) = _NULL_PTE;
 210 }
 211
 212 #ifdef NEED_PMD_INDEX_DESPITE_BEING_2_LEVEL
 213 /**
 214  * pmd_index - returns the index of the entry in the PMD page
 215  * which would control the given virtual address
 216  */
 217 #define pmd_index(address) (((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
 218
 219 #endif
 220
 221 /**
 222  * pgd_index - returns the index of the entry in the PGD page
 223  * which would control the given virtual address
 224  *
 225  * This returns the *index* for the address in the pgd_t
 226  */
 227 #define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
 228
 229 /*
 230  * pgd_offset - find an offset in a page-table-directory
 231  */
 232 #define pgd_offset(mm, addr) ((mm)->pgd + pgd_index(addr))
 233
 234 /*
 235  * pgd_offset_k - get kernel (init_mm) pgd entry pointer for addr
 236  */
 237 #define pgd_offset_k(address) pgd_offset(&init_mm, address)
 238
 239 /**
 240  * pmd_none - check if pmd_entry is mapped
 241  * @pmd_entry:  pmd entry
 242  *
 243  * MIPS checks it against that "invalid pte table" thing.
 244  */
 245 static inline int pmd_none(pmd_t pmd)
 246 {
 247         return pmd_val(pmd) == _NULL_PMD;
 248 }
 249
 250 /**
 251  * pmd_present - is there a page table behind this?
 252  * Essentially the inverse of pmd_none.  We maybe
 253  * save an inline instruction by defining it this
 254  * way, instead of simply "!pmd_none".
 255  */
 256 static inline int pmd_present(pmd_t pmd)
 257 {
 258         return pmd_val(pmd) != (unsigned long)_NULL_PMD;
 259 }
 260
 261 /**
 262  * pmd_bad - check if a PMD entry is "bad". That might mean swapped out.
 263  * As we have no known cause of badness, it's null, as it is for many
 264  * architectures.
 265  */
 266 static inline int pmd_bad(pmd_t pmd)
 267 {
 268         return 0;
 269 }
 270
 271 /*
 272  * pmd_page - converts a PMD entry to a page pointer
 273  */
 274 #define pmd_page(pmd)  (pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT))
 275 #define pmd_pgtable(pmd) pmd_page(pmd)
 276
 277 /**
 278  * pte_none - check if pte is mapped
 279  * @pte: pte_t entry
 280  */
 281 static inline int pte_none(pte_t pte)
 282 {
 283         return pte_val(pte) == _NULL_PTE;
 284 };
 285
 286 /*
 287  * pte_present - check if page is present
 288  */
 289 static inline int pte_present(pte_t pte)
 290 {
 291         return pte_val(pte) & _PAGE_PRESENT;
 292 }
 293
 294 /* mk_pte - make a PTE out of a page pointer and protection bits */
 295 #define mk_pte(page, pgprot) pfn_pte(page_to_pfn(page), (pgprot))
 296
 297 /* pte_page - returns a page (frame pointer/descriptor?) based on a PTE */
 298 #define pte_page(x) pfn_to_page(pte_pfn(x))
 299
 300 /* pte_mkold - mark PTE as not recently accessed */
 301 static inline pte_t pte_mkold(pte_t pte)
 302 {
 303         pte_val(pte) &= ~_PAGE_ACCESSED;
 304         return pte;
 305 }
 306
 307 /* pte_mkyoung - mark PTE as recently accessed */
 308 static inline pte_t pte_mkyoung(pte_t pte)
 309 {
 310         pte_val(pte) |= _PAGE_ACCESSED;
 311         return pte;
 312 }
 313
 314 /* pte_mkclean - mark page as in sync with backing store */
 315 static inline pte_t pte_mkclean(pte_t pte)
 316 {
 317         pte_val(pte) &= ~_PAGE_DIRTY;
 318         return pte;
 319 }
 320
 321 /* pte_mkdirty - mark page as modified */
 322 static inline pte_t pte_mkdirty(pte_t pte)
 323 {
 324         pte_val(pte) |= _PAGE_DIRTY;
 325         return pte;
 326 }
 327
 328 /* pte_young - "is PTE marked as accessed"? */
 329 static inline int pte_young(pte_t pte)
 330 {
 331         return pte_val(pte) & _PAGE_ACCESSED;
 332 }
 333
 334 /* pte_dirty - "is PTE dirty?" */
 335 static inline int pte_dirty(pte_t pte)
 336 {
 337         return pte_val(pte) & _PAGE_DIRTY;
 338 }
 339
 340 /* pte_modify - set protection bits on PTE */
 341 static inline pte_t pte_modify(pte_t pte, pgprot_t prot)
 342 {
 343         pte_val(pte) &= PAGE_MASK;
 344         pte_val(pte) |= pgprot_val(prot);
 345         return pte;
 346 }
 347
 348 /* pte_wrprotect - mark page as not writable */
 349 static inline pte_t pte_wrprotect(pte_t pte)
 350 {
 351         pte_val(pte) &= ~_PAGE_WRITE;
 352         return pte;
 353 }
 354
 355 /* pte_mkwrite - mark page as writable */
 356 static inline pte_t pte_mkwrite(pte_t pte)
 357 {
 358         pte_val(pte) |= _PAGE_WRITE;
 359         return pte;
 360 }
 361
 362 /* pte_mkexec - mark PTE as executable */
 363 static inline pte_t pte_mkexec(pte_t pte)
 364 {
 365         pte_val(pte) |= _PAGE_EXECUTE;
 366         return pte;
 367 }
 368
 369 /* pte_read - "is PTE marked as readable?" */
 370 static inline int pte_read(pte_t pte)
 371 {
 372         return pte_val(pte) & _PAGE_READ;
 373 }
 374
 375 /* pte_write - "is PTE marked as writable?" */
 376 static inline int pte_write(pte_t pte)
 377 {
 378         return pte_val(pte) & _PAGE_WRITE;
 379 }
 380
 381
 382 /* pte_exec - "is PTE marked as executable?" */
 383 static inline int pte_exec(pte_t pte)
 384 {
 385         return pte_val(pte) & _PAGE_EXECUTE;
 386 }
 387
 388 /* __pte_to_swp_entry - extract swap entry from PTE */
 389 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
 390
 391 /* __swp_entry_to_pte - extract PTE from swap entry */
 392 #define __swp_entry_to_pte(x) ((pte_t) { (x).val })
 393
 394 /* pfn_pte - convert page number and protection value to page table entry */
 395 #define pfn_pte(pfn, pgprot) __pte((pfn << PAGE_SHIFT) | pgprot_val(pgprot))
 396
 397 /* pte_pfn - convert pte to page frame number */
 398 #define pte_pfn(pte) (pte_val(pte) >> PAGE_SHIFT)
 399 #define set_pmd(pmdptr, pmdval) (*(pmdptr) = (pmdval))
 400
 401 /*
 402  * set_pte_at - update page table and do whatever magic may be
 403  * necessary to make the underlying hardware/firmware take note.
 404  *
 405  * VM may require a virtual instruction to alert the MMU.
 406  */
 407 #define set_pte_at(mm, addr, ptep, pte) set_pte(ptep, pte)
 408
 409 /*
 410  * May need to invoke the virtual machine as well...
 411  */
 412 #define pte_unmap(pte)          do { } while (0)
 413 #define pte_unmap_nested(pte)   do { } while (0)
 414
 415 /*
 416  * pte_offset_map - returns the linear address of the page table entry
 417  * corresponding to an address
 418  */
 419 #define pte_offset_map(dir, address)                                    \
 420         ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
 421
 422 #define pte_offset_map_nested(pmd, addr) pte_offset_map(pmd, addr)
 423
 424 /* pte_offset_kernel - kernel version of pte_offset */
 425 #define pte_offset_kernel(dir, address) \
 426         ((pte_t *) (unsigned long) __va(pmd_val(*dir) & PAGE_MASK) \
 427                                 +  __pte_offset(address))
 428
 429 /* ZERO_PAGE - returns the globally shared zero page */
 430 #define ZERO_PAGE(vaddr) (virt_to_page(&empty_zero_page))
 431
 432 #define __pte_offset(address) (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 433
 434 /*
 435  * Swap/file PTE definitions.  If _PAGE_PRESENT is zero, the rest of the PTE is
 436  * interpreted as swap information.  The remaining free bits are interpreted as
 437  * swap type/offset tuple.  Rather than have the TLB fill handler test
 438  * _PAGE_PRESENT, we're going to reserve the permissions bits and set them to
 439  * all zeros for swap entries, which speeds up the miss handler at the cost of
 440  * 3 bits of offset.  That trade-off can be revisited if necessary, but Hexagon
 441  * processor architecture and target applications suggest a lot of TLB misses
 442  * and not much swap space.
 443  *
 444  * Format of swap PTE:
 445  *      bit     0:      Present (zero)
 446  *      bits    1-5:    swap type (arch independent layer uses 5 bits max)
 447  *      bits    6-9:    bits 3:0 of offset
 448  *      bits    10-12:  effectively _PAGE_PROTNONE (all zero)
 449  *      bits    13-31:  bits 22:4 of swap offset
 450  *
 451  * The split offset makes some of the following macros a little gnarly,
 452  * but there's plenty of precedent for this sort of thing.
 453  */
 454
 455 /* Used for swap PTEs */
 456 #define __swp_type(swp_pte)             (((swp_pte).val >> 1) & 0x1f)
 457
 458 #define __swp_offset(swp_pte) \
 459         ((((swp_pte).val >> 6) & 0xf) | (((swp_pte).val >> 9) & 0x7ffff0))
 460
 461 #define __swp_entry(type, offset) \
 462         ((swp_entry_t)  { \
 463                 ((type << 1) | \
 464                  ((offset & 0x7ffff0) << 9) | ((offset & 0xf) << 6)) })
 465
 466 /*  Oh boy.  There are a lot of possible arch overrides found in this file.  */
 467 #include <asm-generic/pgtable.h>
 468
 469 #endif