1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) 4 * 5 * vineetg: May 2011 6 * -Folded PAGE_PRESENT (used by VM) and PAGE_VALID (used by MMU) into 1. 7 * They are semantically the same although in different contexts 8 * VALID marks a TLB entry exists and it will only happen if PRESENT 9 * - Utilise some unused free bits to confine PTE flags to 12 bits 10 * This is a must for 4k pg-sz 11 * 12 * vineetg: Mar 2011 - changes to accommodate MMU TLB Page Descriptor mods 13 * -TLB Locking never really existed, except for initial specs 14 * -SILENT_xxx not needed for our port 15 * -Per my request, MMU V3 changes the layout of some of the bits 16 * to avoid a few shifts in TLB Miss handlers. 17 * 18 * vineetg: April 2010 19 * -PGD entry no longer contains any flags. If empty it is 0, otherwise has 20 * Pg-Tbl ptr. Thus pmd_present(), pmd_valid(), pmd_set( ) become simpler 21 * 22 * vineetg: April 2010 23 * -Switched form 8:11:13 split for page table lookup to 11:8:13 24 * -this speeds up page table allocation itself as we now have to memset 1K 25 * instead of 8k per page table. 26 * -TODO: Right now page table alloc is 8K and rest 7K is unused 27 * need to optimise it 28 * 29 * Amit Bhor, Sameer Dhavale: Codito Technologies 2004 30 */ 31 32 #ifndef _ASM_ARC_PGTABLE_H 33 #define _ASM_ARC_PGTABLE_H 34 35 #include <linux/bits.h> 36 #include <asm-generic/pgtable-nopmd.h> 37 #include <asm/page.h> 38 #include <asm/mmu.h> /* to propagate CONFIG_ARC_MMU_VER <n> */ 39 40 /************************************************************************** 41 * Page Table Flags 42 * 43 * ARC700 MMU only deals with softare managed TLB entries. 44 * Page Tables are purely for Linux VM's consumption and the bits below are 45 * suited to that (uniqueness). Hence some are not implemented in the TLB and 46 * some have different value in TLB. 47 * e.g. MMU v2: K_READ bit is 8 and so is GLOBAL (possible because they live in 48 * seperate PD0 and PD1, which combined forms a translation entry) 49 * while for PTE perspective, they are 8 and 9 respectively 50 * with MMU v3: Most bits (except SHARED) represent the exact hardware pos 51 * (saves some bit shift ops in TLB Miss hdlrs) 52 */ 53 54 #if (CONFIG_ARC_MMU_VER <= 2) 55 56 #define _PAGE_ACCESSED (1<<1) /* Page is accessed (S) */ 57 #define _PAGE_CACHEABLE (1<<2) /* Page is cached (H) */ 58 #define _PAGE_EXECUTE (1<<3) /* Page has user execute perm (H) */ 59 #define _PAGE_WRITE (1<<4) /* Page has user write perm (H) */ 60 #define _PAGE_READ (1<<5) /* Page has user read perm (H) */ 61 #define _PAGE_DIRTY (1<<6) /* Page modified (dirty) (S) */ 62 #define _PAGE_SPECIAL (1<<7) 63 #define _PAGE_GLOBAL (1<<8) /* Page is global (H) */ 64 #define _PAGE_PRESENT (1<<10) /* TLB entry is valid (H) */ 65 66 #else /* MMU v3 onwards */ 67 68 #define _PAGE_CACHEABLE (1<<0) /* Page is cached (H) */ 69 #define _PAGE_EXECUTE (1<<1) /* Page has user execute perm (H) */ 70 #define _PAGE_WRITE (1<<2) /* Page has user write perm (H) */ 71 #define _PAGE_READ (1<<3) /* Page has user read perm (H) */ 72 #define _PAGE_ACCESSED (1<<4) /* Page is accessed (S) */ 73 #define _PAGE_DIRTY (1<<5) /* Page modified (dirty) (S) */ 74 #define _PAGE_SPECIAL (1<<6) 75 76 #if (CONFIG_ARC_MMU_VER >= 4) 77 #define _PAGE_WTHRU (1<<7) /* Page cache mode write-thru (H) */ 78 #endif 79 80 #define _PAGE_GLOBAL (1<<8) /* Page is global (H) */ 81 #define _PAGE_PRESENT (1<<9) /* TLB entry is valid (H) */ 82 83 #if (CONFIG_ARC_MMU_VER >= 4) 84 #define _PAGE_HW_SZ (1<<10) /* Page Size indicator (H): 0 normal, 1 super */ 85 #endif 86 87 #define _PAGE_SHARED_CODE (1<<11) /* Shared Code page with cmn vaddr 88 usable for shared TLB entries (H) */ 89 90 #define _PAGE_UNUSED_BIT (1<<12) 91 #endif 92 93 /* vmalloc permissions */ 94 #define _K_PAGE_PERMS (_PAGE_EXECUTE | _PAGE_WRITE | _PAGE_READ | \ 95 _PAGE_GLOBAL | _PAGE_PRESENT) 96 97 #ifndef CONFIG_ARC_CACHE_PAGES 98 #undef _PAGE_CACHEABLE 99 #define _PAGE_CACHEABLE 0 100 #endif 101 102 #ifndef _PAGE_HW_SZ 103 #define _PAGE_HW_SZ 0 104 #endif 105 106 /* Defaults for every user page */ 107 #define ___DEF (_PAGE_PRESENT | _PAGE_CACHEABLE) 108 109 /* Set of bits not changed in pte_modify */ 110 #define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_SPECIAL) 111 112 /* More Abbrevaited helpers */ 113 #define PAGE_U_NONE __pgprot(___DEF) 114 #define PAGE_U_R __pgprot(___DEF | _PAGE_READ) 115 #define PAGE_U_W_R __pgprot(___DEF | _PAGE_READ | _PAGE_WRITE) 116 #define PAGE_U_X_R __pgprot(___DEF | _PAGE_READ | _PAGE_EXECUTE) 117 #define PAGE_U_X_W_R __pgprot(___DEF | _PAGE_READ | _PAGE_WRITE | \ 118 _PAGE_EXECUTE) 119 120 #define PAGE_SHARED PAGE_U_W_R 121 122 /* While kernel runs out of unstranslated space, vmalloc/modules use a chunk of 123 * user vaddr space - visible in all addr spaces, but kernel mode only 124 * Thus Global, all-kernel-access, no-user-access, cached 125 */ 126 #define PAGE_KERNEL __pgprot(_K_PAGE_PERMS | _PAGE_CACHEABLE) 127 128 /* ioremap */ 129 #define PAGE_KERNEL_NO_CACHE __pgprot(_K_PAGE_PERMS) 130 131 /* Masks for actual TLB "PD"s */ 132 #define PTE_BITS_IN_PD0 (_PAGE_GLOBAL | _PAGE_PRESENT | _PAGE_HW_SZ) 133 #define PTE_BITS_RWX (_PAGE_EXECUTE | _PAGE_WRITE | _PAGE_READ) 134 135 #ifdef CONFIG_ARC_HAS_PAE40 136 #define PTE_BITS_NON_RWX_IN_PD1 (0xff00000000 | PAGE_MASK | _PAGE_CACHEABLE) 137 #else 138 #define PTE_BITS_NON_RWX_IN_PD1 (PAGE_MASK | _PAGE_CACHEABLE) 139 #endif 140 141 /************************************************************************** 142 * Mapping of vm_flags (Generic VM) to PTE flags (arch specific) 143 * 144 * Certain cases have 1:1 mapping 145 * e.g. __P101 means VM_READ, VM_EXEC and !VM_SHARED 146 * which directly corresponds to PAGE_U_X_R 147 * 148 * Other rules which cause the divergence from 1:1 mapping 149 * 150 * 1. Although ARC700 can do exclusive execute/write protection (meaning R 151 * can be tracked independet of X/W unlike some other CPUs), still to 152 * keep things consistent with other archs: 153 * -Write implies Read: W => R 154 * -Execute implies Read: X => R 155 * 156 * 2. Pvt Writable doesn't have Write Enabled initially: Pvt-W => !W 157 * This is to enable COW mechanism 158 */ 159 /* xwr */ 160 #define __P000 PAGE_U_NONE 161 #define __P001 PAGE_U_R 162 #define __P010 PAGE_U_R /* Pvt-W => !W */ 163 #define __P011 PAGE_U_R /* Pvt-W => !W */ 164 #define __P100 PAGE_U_X_R /* X => R */ 165 #define __P101 PAGE_U_X_R 166 #define __P110 PAGE_U_X_R /* Pvt-W => !W and X => R */ 167 #define __P111 PAGE_U_X_R /* Pvt-W => !W */ 168 169 #define __S000 PAGE_U_NONE 170 #define __S001 PAGE_U_R 171 #define __S010 PAGE_U_W_R /* W => R */ 172 #define __S011 PAGE_U_W_R 173 #define __S100 PAGE_U_X_R /* X => R */ 174 #define __S101 PAGE_U_X_R 175 #define __S110 PAGE_U_X_W_R /* X => R */ 176 #define __S111 PAGE_U_X_W_R 177 178 /**************************************************************** 179 * 2 tier (PGD:PTE) software page walker 180 * 181 * [31] 32 bit virtual address [0] 182 * ------------------------------------------------------- 183 * | | <------------ PGDIR_SHIFT ----------> | 184 * | | | 185 * | BITS_FOR_PGD | BITS_FOR_PTE | <-- PAGE_SHIFT --> | 186 * ------------------------------------------------------- 187 * | | | 188 * | | --> off in page frame 189 * | ---> index into Page Table 190 * ----> index into Page Directory 191 * 192 * In a single page size configuration, only PAGE_SHIFT is fixed 193 * So both PGD and PTE sizing can be tweaked 194 * e.g. 8K page (PAGE_SHIFT 13) can have 195 * - PGDIR_SHIFT 21 -> 11:8:13 address split 196 * - PGDIR_SHIFT 24 -> 8:11:13 address split 197 * 198 * If Super Page is configured, PGDIR_SHIFT becomes fixed too, 199 * so the sizing flexibility is gone. 200 */ 201 202 #if defined(CONFIG_ARC_HUGEPAGE_16M) 203 #define PGDIR_SHIFT 24 204 #elif defined(CONFIG_ARC_HUGEPAGE_2M) 205 #define PGDIR_SHIFT 21 206 #else 207 /* 208 * Only Normal page support so "hackable" (see comment above) 209 * Default value provides 11:8:13 (8K), 11:9:12 (4K) 210 */ 211 #define PGDIR_SHIFT 21 212 #endif 213 214 #define BITS_FOR_PTE (PGDIR_SHIFT - PAGE_SHIFT) 215 #define BITS_FOR_PGD (32 - PGDIR_SHIFT) 216 217 #define PGDIR_SIZE BIT(PGDIR_SHIFT) /* vaddr span, not PDG sz */ 218 #define PGDIR_MASK (~(PGDIR_SIZE-1)) 219 220 #define PTRS_PER_PTE BIT(BITS_FOR_PTE) 221 #define PTRS_PER_PGD BIT(BITS_FOR_PGD) 222 223 /* 224 * Number of entries a user land program use. 225 * TASK_SIZE is the maximum vaddr that can be used by a userland program. 226 */ 227 #define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE) 228 229 /* 230 * No special requirements for lowest virtual address we permit any user space 231 * mapping to be mapped at. 232 */ 233 #define FIRST_USER_ADDRESS 0UL 234 235 236 /**************************************************************** 237 * Bucket load of VM Helpers 238 */ 239 240 #ifndef __ASSEMBLY__ 241 242 #define pte_ERROR(e) \ 243 pr_crit("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e)) 244 #define pgd_ERROR(e) \ 245 pr_crit("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e)) 246 247 /* the zero page used for uninitialized and anonymous pages */ 248 extern char empty_zero_page[PAGE_SIZE]; 249 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page)) 250 251 #define pte_unmap(pte) do { } while (0) 252 #define pte_unmap_nested(pte) do { } while (0) 253 254 #define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval)) 255 #define set_pmd(pmdptr, pmdval) (*(pmdptr) = pmdval) 256 257 /* find the page descriptor of the Page Tbl ref by PMD entry */ 258 #define pmd_page(pmd) virt_to_page(pmd_val(pmd) & PAGE_MASK) 259 260 /* find the logical addr (phy for ARC) of the Page Tbl ref by PMD entry */ 261 #define pmd_page_vaddr(pmd) (pmd_val(pmd) & PAGE_MASK) 262 263 /* In a 2 level sys, setup the PGD entry with PTE value */ 264 static inline void pmd_set(pmd_t *pmdp, pte_t *ptep) 265 { 266 pmd_val(*pmdp) = (unsigned long)ptep; 267 } 268 269 #define pte_none(x) (!pte_val(x)) 270 #define pte_present(x) (pte_val(x) & _PAGE_PRESENT) 271 #define pte_clear(mm, addr, ptep) set_pte_at(mm, addr, ptep, __pte(0)) 272 273 #define pmd_none(x) (!pmd_val(x)) 274 #define pmd_bad(x) ((pmd_val(x) & ~PAGE_MASK)) 275 #define pmd_present(x) (pmd_val(x)) 276 #define pmd_clear(xp) do { pmd_val(*(xp)) = 0; } while (0) 277 278 #define pte_page(pte) pfn_to_page(pte_pfn(pte)) 279 #define mk_pte(page, prot) pfn_pte(page_to_pfn(page), prot) 280 #define pfn_pte(pfn, prot) __pte(__pfn_to_phys(pfn) | pgprot_val(prot)) 281 282 /* Don't use virt_to_pfn for macros below: could cause truncations for PAE40*/ 283 #define pte_pfn(pte) (pte_val(pte) >> PAGE_SHIFT) 284 #define __pte_index(addr) (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) 285 286 /* 287 * pte_offset gets a @ptr to PMD entry (PGD in our 2-tier paging system) 288 * and returns ptr to PTE entry corresponding to @addr 289 */ 290 #define pte_offset(dir, addr) ((pte_t *)(pmd_page_vaddr(*dir)) +\ 291 __pte_index(addr)) 292 293 /* No mapping of Page Tables in high mem etc, so following same as above */ 294 #define pte_offset_kernel(dir, addr) pte_offset(dir, addr) 295 #define pte_offset_map(dir, addr) pte_offset(dir, addr) 296 297 /* Zoo of pte_xxx function */ 298 #define pte_read(pte) (pte_val(pte) & _PAGE_READ) 299 #define pte_write(pte) (pte_val(pte) & _PAGE_WRITE) 300 #define pte_dirty(pte) (pte_val(pte) & _PAGE_DIRTY) 301 #define pte_young(pte) (pte_val(pte) & _PAGE_ACCESSED) 302 #define pte_special(pte) (pte_val(pte) & _PAGE_SPECIAL) 303 304 #define PTE_BIT_FUNC(fn, op) \ 305 static inline pte_t pte_##fn(pte_t pte) { pte_val(pte) op; return pte; } 306 307 PTE_BIT_FUNC(mknotpresent, &= ~(_PAGE_PRESENT)); 308 PTE_BIT_FUNC(wrprotect, &= ~(_PAGE_WRITE)); 309 PTE_BIT_FUNC(mkwrite, |= (_PAGE_WRITE)); 310 PTE_BIT_FUNC(mkclean, &= ~(_PAGE_DIRTY)); 311 PTE_BIT_FUNC(mkdirty, |= (_PAGE_DIRTY)); 312 PTE_BIT_FUNC(mkold, &= ~(_PAGE_ACCESSED)); 313 PTE_BIT_FUNC(mkyoung, |= (_PAGE_ACCESSED)); 314 PTE_BIT_FUNC(exprotect, &= ~(_PAGE_EXECUTE)); 315 PTE_BIT_FUNC(mkexec, |= (_PAGE_EXECUTE)); 316 PTE_BIT_FUNC(mkspecial, |= (_PAGE_SPECIAL)); 317 PTE_BIT_FUNC(mkhuge, |= (_PAGE_HW_SZ)); 318 319 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) 320 { 321 return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot)); 322 } 323 324 /* Macro to mark a page protection as uncacheable */ 325 #define pgprot_noncached(prot) (__pgprot(pgprot_val(prot) & ~_PAGE_CACHEABLE)) 326 327 static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, 328 pte_t *ptep, pte_t pteval) 329 { 330 set_pte(ptep, pteval); 331 } 332 333 /* 334 * All kernel related VM pages are in init's mm. 335 */ 336 #define pgd_offset_k(address) pgd_offset(&init_mm, address) 337 #define pgd_index(addr) ((addr) >> PGDIR_SHIFT) 338 #define pgd_offset(mm, addr) (((mm)->pgd)+pgd_index(addr)) 339 340 /* 341 * Macro to quickly access the PGD entry, utlising the fact that some 342 * arch may cache the pointer to Page Directory of "current" task 343 * in a MMU register 344 * 345 * Thus task->mm->pgd (3 pointer dereferences, cache misses etc simply 346 * becomes read a register 347 * 348 * ********CAUTION*******: 349 * Kernel code might be dealing with some mm_struct of NON "current" 350 * Thus use this macro only when you are certain that "current" is current 351 * e.g. when dealing with signal frame setup code etc 352 */ 353 #ifdef ARC_USE_SCRATCH_REG 354 #define pgd_offset_fast(mm, addr) \ 355 ({ \ 356 pgd_t *pgd_base = (pgd_t *) read_aux_reg(ARC_REG_SCRATCH_DATA0); \ 357 pgd_base + pgd_index(addr); \ 358 }) 359 #else 360 #define pgd_offset_fast(mm, addr) pgd_offset(mm, addr) 361 #endif 362 363 extern pgd_t swapper_pg_dir[] __aligned(PAGE_SIZE); 364 void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, 365 pte_t *ptep); 366 367 /* Encode swap {type,off} tuple into PTE 368 * We reserve 13 bits for 5-bit @type, keeping bits 12-5 zero, ensuring that 369 * PAGE_PRESENT is zero in a PTE holding swap "identifier" 370 */ 371 #define __swp_entry(type, off) ((swp_entry_t) { \ 372 ((type) & 0x1f) | ((off) << 13) }) 373 374 /* Decode a PTE containing swap "identifier "into constituents */ 375 #define __swp_type(pte_lookalike) (((pte_lookalike).val) & 0x1f) 376 #define __swp_offset(pte_lookalike) ((pte_lookalike).val >> 13) 377 378 /* NOPs, to keep generic kernel happy */ 379 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) 380 #define __swp_entry_to_pte(x) ((pte_t) { (x).val }) 381 382 #define kern_addr_valid(addr) (1) 383 384 /* 385 * remap a physical page `pfn' of size `size' with page protection `prot' 386 * into virtual address `from' 387 */ 388 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 389 #include <asm/hugepage.h> 390 #endif 391 392 #include <asm-generic/pgtable.h> 393 394 /* to cope with aliasing VIPT cache */ 395 #define HAVE_ARCH_UNMAPPED_AREA 396 397 #endif /* __ASSEMBLY__ */ 398 399 #endif 400