1 /* 2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * vineetg: May 2011 9 * -Folded PAGE_PRESENT (used by VM) and PAGE_VALID (used by MMU) into 1. 10 * They are semantically the same although in different contexts 11 * VALID marks a TLB entry exists and it will only happen if PRESENT 12 * - Utilise some unused free bits to confine PTE flags to 12 bits 13 * This is a must for 4k pg-sz 14 * 15 * vineetg: Mar 2011 - changes to accommodate MMU TLB Page Descriptor mods 16 * -TLB Locking never really existed, except for initial specs 17 * -SILENT_xxx not needed for our port 18 * -Per my request, MMU V3 changes the layout of some of the bits 19 * to avoid a few shifts in TLB Miss handlers. 20 * 21 * vineetg: April 2010 22 * -PGD entry no longer contains any flags. If empty it is 0, otherwise has 23 * Pg-Tbl ptr. Thus pmd_present(), pmd_valid(), pmd_set( ) become simpler 24 * 25 * vineetg: April 2010 26 * -Switched form 8:11:13 split for page table lookup to 11:8:13 27 * -this speeds up page table allocation itself as we now have to memset 1K 28 * instead of 8k per page table. 29 * -TODO: Right now page table alloc is 8K and rest 7K is unused 30 * need to optimise it 31 * 32 * Amit Bhor, Sameer Dhavale: Codito Technologies 2004 33 */ 34 35 #ifndef _ASM_ARC_PGTABLE_H 36 #define _ASM_ARC_PGTABLE_H 37 38 #include <asm/page.h> 39 #include <asm/mmu.h> 40 #include <asm-generic/pgtable-nopmd.h> 41 #include <linux/const.h> 42 43 /************************************************************************** 44 * Page Table Flags 45 * 46 * ARC700 MMU only deals with softare managed TLB entries. 47 * Page Tables are purely for Linux VM's consumption and the bits below are 48 * suited to that (uniqueness). Hence some are not implemented in the TLB and 49 * some have different value in TLB. 50 * e.g. MMU v2: K_READ bit is 8 and so is GLOBAL (possible because they live in 51 * seperate PD0 and PD1, which combined forms a translation entry) 52 * while for PTE perspective, they are 8 and 9 respectively 53 * with MMU v3: Most bits (except SHARED) represent the exact hardware pos 54 * (saves some bit shift ops in TLB Miss hdlrs) 55 */ 56 57 #if (CONFIG_ARC_MMU_VER <= 2) 58 59 #define _PAGE_ACCESSED (1<<1) /* Page is accessed (S) */ 60 #define _PAGE_CACHEABLE (1<<2) /* Page is cached (H) */ 61 #define _PAGE_EXECUTE (1<<3) /* Page has user execute perm (H) */ 62 #define _PAGE_WRITE (1<<4) /* Page has user write perm (H) */ 63 #define _PAGE_READ (1<<5) /* Page has user read perm (H) */ 64 #define _PAGE_DIRTY (1<<6) /* Page modified (dirty) (S) */ 65 #define _PAGE_SPECIAL (1<<7) 66 #define _PAGE_GLOBAL (1<<8) /* Page is global (H) */ 67 #define _PAGE_PRESENT (1<<10) /* TLB entry is valid (H) */ 68 69 #else /* MMU v3 onwards */ 70 71 #define _PAGE_CACHEABLE (1<<0) /* Page is cached (H) */ 72 #define _PAGE_EXECUTE (1<<1) /* Page has user execute perm (H) */ 73 #define _PAGE_WRITE (1<<2) /* Page has user write perm (H) */ 74 #define _PAGE_READ (1<<3) /* Page has user read perm (H) */ 75 #define _PAGE_ACCESSED (1<<4) /* Page is accessed (S) */ 76 #define _PAGE_DIRTY (1<<5) /* Page modified (dirty) (S) */ 77 #define _PAGE_SPECIAL (1<<6) 78 79 #if (CONFIG_ARC_MMU_VER >= 4) 80 #define _PAGE_WTHRU (1<<7) /* Page cache mode write-thru (H) */ 81 #endif 82 83 #define _PAGE_GLOBAL (1<<8) /* Page is global (H) */ 84 #define _PAGE_PRESENT (1<<9) /* TLB entry is valid (H) */ 85 86 #if (CONFIG_ARC_MMU_VER >= 4) 87 #define _PAGE_HW_SZ (1<<10) /* Page Size indicator (H): 0 normal, 1 super */ 88 #endif 89 90 #define _PAGE_SHARED_CODE (1<<11) /* Shared Code page with cmn vaddr 91 usable for shared TLB entries (H) */ 92 93 #define _PAGE_UNUSED_BIT (1<<12) 94 #endif 95 96 /* vmalloc permissions */ 97 #define _K_PAGE_PERMS (_PAGE_EXECUTE | _PAGE_WRITE | _PAGE_READ | \ 98 _PAGE_GLOBAL | _PAGE_PRESENT) 99 100 #ifndef CONFIG_ARC_CACHE_PAGES 101 #undef _PAGE_CACHEABLE 102 #define _PAGE_CACHEABLE 0 103 #endif 104 105 #ifndef _PAGE_HW_SZ 106 #define _PAGE_HW_SZ 0 107 #endif 108 109 /* Defaults for every user page */ 110 #define ___DEF (_PAGE_PRESENT | _PAGE_CACHEABLE) 111 112 /* Set of bits not changed in pte_modify */ 113 #define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_SPECIAL) 114 115 /* More Abbrevaited helpers */ 116 #define PAGE_U_NONE __pgprot(___DEF) 117 #define PAGE_U_R __pgprot(___DEF | _PAGE_READ) 118 #define PAGE_U_W_R __pgprot(___DEF | _PAGE_READ | _PAGE_WRITE) 119 #define PAGE_U_X_R __pgprot(___DEF | _PAGE_READ | _PAGE_EXECUTE) 120 #define PAGE_U_X_W_R __pgprot(___DEF | _PAGE_READ | _PAGE_WRITE | \ 121 _PAGE_EXECUTE) 122 123 #define PAGE_SHARED PAGE_U_W_R 124 125 /* While kernel runs out of unstranslated space, vmalloc/modules use a chunk of 126 * user vaddr space - visible in all addr spaces, but kernel mode only 127 * Thus Global, all-kernel-access, no-user-access, cached 128 */ 129 #define PAGE_KERNEL __pgprot(_K_PAGE_PERMS | _PAGE_CACHEABLE) 130 131 /* ioremap */ 132 #define PAGE_KERNEL_NO_CACHE __pgprot(_K_PAGE_PERMS) 133 134 /* Masks for actual TLB "PD"s */ 135 #define PTE_BITS_IN_PD0 (_PAGE_GLOBAL | _PAGE_PRESENT | _PAGE_HW_SZ) 136 #define PTE_BITS_RWX (_PAGE_EXECUTE | _PAGE_WRITE | _PAGE_READ) 137 138 #ifdef CONFIG_ARC_HAS_PAE40 139 #define PTE_BITS_NON_RWX_IN_PD1 (0xff00000000 | PAGE_MASK | _PAGE_CACHEABLE) 140 #else 141 #define PTE_BITS_NON_RWX_IN_PD1 (PAGE_MASK | _PAGE_CACHEABLE) 142 #endif 143 144 /************************************************************************** 145 * Mapping of vm_flags (Generic VM) to PTE flags (arch specific) 146 * 147 * Certain cases have 1:1 mapping 148 * e.g. __P101 means VM_READ, VM_EXEC and !VM_SHARED 149 * which directly corresponds to PAGE_U_X_R 150 * 151 * Other rules which cause the divergence from 1:1 mapping 152 * 153 * 1. Although ARC700 can do exclusive execute/write protection (meaning R 154 * can be tracked independet of X/W unlike some other CPUs), still to 155 * keep things consistent with other archs: 156 * -Write implies Read: W => R 157 * -Execute implies Read: X => R 158 * 159 * 2. Pvt Writable doesn't have Write Enabled initially: Pvt-W => !W 160 * This is to enable COW mechanism 161 */ 162 /* xwr */ 163 #define __P000 PAGE_U_NONE 164 #define __P001 PAGE_U_R 165 #define __P010 PAGE_U_R /* Pvt-W => !W */ 166 #define __P011 PAGE_U_R /* Pvt-W => !W */ 167 #define __P100 PAGE_U_X_R /* X => R */ 168 #define __P101 PAGE_U_X_R 169 #define __P110 PAGE_U_X_R /* Pvt-W => !W and X => R */ 170 #define __P111 PAGE_U_X_R /* Pvt-W => !W */ 171 172 #define __S000 PAGE_U_NONE 173 #define __S001 PAGE_U_R 174 #define __S010 PAGE_U_W_R /* W => R */ 175 #define __S011 PAGE_U_W_R 176 #define __S100 PAGE_U_X_R /* X => R */ 177 #define __S101 PAGE_U_X_R 178 #define __S110 PAGE_U_X_W_R /* X => R */ 179 #define __S111 PAGE_U_X_W_R 180 181 /**************************************************************** 182 * 2 tier (PGD:PTE) software page walker 183 * 184 * [31] 32 bit virtual address [0] 185 * ------------------------------------------------------- 186 * | | <------------ PGDIR_SHIFT ----------> | 187 * | | | 188 * | BITS_FOR_PGD | BITS_FOR_PTE | <-- PAGE_SHIFT --> | 189 * ------------------------------------------------------- 190 * | | | 191 * | | --> off in page frame 192 * | ---> index into Page Table 193 * ----> index into Page Directory 194 * 195 * In a single page size configuration, only PAGE_SHIFT is fixed 196 * So both PGD and PTE sizing can be tweaked 197 * e.g. 8K page (PAGE_SHIFT 13) can have 198 * - PGDIR_SHIFT 21 -> 11:8:13 address split 199 * - PGDIR_SHIFT 24 -> 8:11:13 address split 200 * 201 * If Super Page is configured, PGDIR_SHIFT becomes fixed too, 202 * so the sizing flexibility is gone. 203 */ 204 205 #if defined(CONFIG_ARC_HUGEPAGE_16M) 206 #define PGDIR_SHIFT 24 207 #elif defined(CONFIG_ARC_HUGEPAGE_2M) 208 #define PGDIR_SHIFT 21 209 #else 210 /* 211 * Only Normal page support so "hackable" (see comment above) 212 * Default value provides 11:8:13 (8K), 11:9:12 (4K) 213 */ 214 #define PGDIR_SHIFT 21 215 #endif 216 217 #define BITS_FOR_PTE (PGDIR_SHIFT - PAGE_SHIFT) 218 #define BITS_FOR_PGD (32 - PGDIR_SHIFT) 219 220 #define PGDIR_SIZE _BITUL(PGDIR_SHIFT) /* vaddr span, not PDG sz */ 221 #define PGDIR_MASK (~(PGDIR_SIZE-1)) 222 223 #define PTRS_PER_PTE _BITUL(BITS_FOR_PTE) 224 #define PTRS_PER_PGD _BITUL(BITS_FOR_PGD) 225 226 /* 227 * Number of entries a user land program use. 228 * TASK_SIZE is the maximum vaddr that can be used by a userland program. 229 */ 230 #define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE) 231 232 /* 233 * No special requirements for lowest virtual address we permit any user space 234 * mapping to be mapped at. 235 */ 236 #define FIRST_USER_ADDRESS 0UL 237 238 239 /**************************************************************** 240 * Bucket load of VM Helpers 241 */ 242 243 #ifndef __ASSEMBLY__ 244 245 #define pte_ERROR(e) \ 246 pr_crit("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e)) 247 #define pgd_ERROR(e) \ 248 pr_crit("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e)) 249 250 /* the zero page used for uninitialized and anonymous pages */ 251 extern char empty_zero_page[PAGE_SIZE]; 252 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page)) 253 254 #define pte_unmap(pte) do { } while (0) 255 #define pte_unmap_nested(pte) do { } while (0) 256 257 #define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval)) 258 #define set_pmd(pmdptr, pmdval) (*(pmdptr) = pmdval) 259 260 /* find the page descriptor of the Page Tbl ref by PMD entry */ 261 #define pmd_page(pmd) virt_to_page(pmd_val(pmd) & PAGE_MASK) 262 263 /* find the logical addr (phy for ARC) of the Page Tbl ref by PMD entry */ 264 #define pmd_page_vaddr(pmd) (pmd_val(pmd) & PAGE_MASK) 265 266 /* In a 2 level sys, setup the PGD entry with PTE value */ 267 static inline void pmd_set(pmd_t *pmdp, pte_t *ptep) 268 { 269 pmd_val(*pmdp) = (unsigned long)ptep; 270 } 271 272 #define pte_none(x) (!pte_val(x)) 273 #define pte_present(x) (pte_val(x) & _PAGE_PRESENT) 274 #define pte_clear(mm, addr, ptep) set_pte_at(mm, addr, ptep, __pte(0)) 275 276 #define pmd_none(x) (!pmd_val(x)) 277 #define pmd_bad(x) ((pmd_val(x) & ~PAGE_MASK)) 278 #define pmd_present(x) (pmd_val(x)) 279 #define pmd_clear(xp) do { pmd_val(*(xp)) = 0; } while (0) 280 281 #define pte_page(pte) pfn_to_page(pte_pfn(pte)) 282 #define mk_pte(page, prot) pfn_pte(page_to_pfn(page), prot) 283 #define pfn_pte(pfn, prot) __pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot)) 284 285 /* Don't use virt_to_pfn for macros below: could cause truncations for PAE40*/ 286 #define pte_pfn(pte) (pte_val(pte) >> PAGE_SHIFT) 287 #define __pte_index(addr) (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) 288 289 /* 290 * pte_offset gets a @ptr to PMD entry (PGD in our 2-tier paging system) 291 * and returns ptr to PTE entry corresponding to @addr 292 */ 293 #define pte_offset(dir, addr) ((pte_t *)(pmd_page_vaddr(*dir)) +\ 294 __pte_index(addr)) 295 296 /* No mapping of Page Tables in high mem etc, so following same as above */ 297 #define pte_offset_kernel(dir, addr) pte_offset(dir, addr) 298 #define pte_offset_map(dir, addr) pte_offset(dir, addr) 299 300 /* Zoo of pte_xxx function */ 301 #define pte_read(pte) (pte_val(pte) & _PAGE_READ) 302 #define pte_write(pte) (pte_val(pte) & _PAGE_WRITE) 303 #define pte_dirty(pte) (pte_val(pte) & _PAGE_DIRTY) 304 #define pte_young(pte) (pte_val(pte) & _PAGE_ACCESSED) 305 #define pte_special(pte) (pte_val(pte) & _PAGE_SPECIAL) 306 307 #define PTE_BIT_FUNC(fn, op) \ 308 static inline pte_t pte_##fn(pte_t pte) { pte_val(pte) op; return pte; } 309 310 PTE_BIT_FUNC(mknotpresent, &= ~(_PAGE_PRESENT)); 311 PTE_BIT_FUNC(wrprotect, &= ~(_PAGE_WRITE)); 312 PTE_BIT_FUNC(mkwrite, |= (_PAGE_WRITE)); 313 PTE_BIT_FUNC(mkclean, &= ~(_PAGE_DIRTY)); 314 PTE_BIT_FUNC(mkdirty, |= (_PAGE_DIRTY)); 315 PTE_BIT_FUNC(mkold, &= ~(_PAGE_ACCESSED)); 316 PTE_BIT_FUNC(mkyoung, |= (_PAGE_ACCESSED)); 317 PTE_BIT_FUNC(exprotect, &= ~(_PAGE_EXECUTE)); 318 PTE_BIT_FUNC(mkexec, |= (_PAGE_EXECUTE)); 319 PTE_BIT_FUNC(mkspecial, |= (_PAGE_SPECIAL)); 320 PTE_BIT_FUNC(mkhuge, |= (_PAGE_HW_SZ)); 321 322 #define __HAVE_ARCH_PTE_SPECIAL 323 324 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) 325 { 326 return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot)); 327 } 328 329 /* Macro to mark a page protection as uncacheable */ 330 #define pgprot_noncached(prot) (__pgprot(pgprot_val(prot) & ~_PAGE_CACHEABLE)) 331 332 static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, 333 pte_t *ptep, pte_t pteval) 334 { 335 set_pte(ptep, pteval); 336 } 337 338 /* 339 * All kernel related VM pages are in init's mm. 340 */ 341 #define pgd_offset_k(address) pgd_offset(&init_mm, address) 342 #define pgd_index(addr) ((addr) >> PGDIR_SHIFT) 343 #define pgd_offset(mm, addr) (((mm)->pgd)+pgd_index(addr)) 344 345 /* 346 * Macro to quickly access the PGD entry, utlising the fact that some 347 * arch may cache the pointer to Page Directory of "current" task 348 * in a MMU register 349 * 350 * Thus task->mm->pgd (3 pointer dereferences, cache misses etc simply 351 * becomes read a register 352 * 353 * ********CAUTION*******: 354 * Kernel code might be dealing with some mm_struct of NON "current" 355 * Thus use this macro only when you are certain that "current" is current 356 * e.g. when dealing with signal frame setup code etc 357 */ 358 #ifndef CONFIG_SMP 359 #define pgd_offset_fast(mm, addr) \ 360 ({ \ 361 pgd_t *pgd_base = (pgd_t *) read_aux_reg(ARC_REG_SCRATCH_DATA0); \ 362 pgd_base + pgd_index(addr); \ 363 }) 364 #else 365 #define pgd_offset_fast(mm, addr) pgd_offset(mm, addr) 366 #endif 367 368 extern pgd_t swapper_pg_dir[] __aligned(PAGE_SIZE); 369 void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, 370 pte_t *ptep); 371 372 /* Encode swap {type,off} tuple into PTE 373 * We reserve 13 bits for 5-bit @type, keeping bits 12-5 zero, ensuring that 374 * PAGE_PRESENT is zero in a PTE holding swap "identifier" 375 */ 376 #define __swp_entry(type, off) ((swp_entry_t) { \ 377 ((type) & 0x1f) | ((off) << 13) }) 378 379 /* Decode a PTE containing swap "identifier "into constituents */ 380 #define __swp_type(pte_lookalike) (((pte_lookalike).val) & 0x1f) 381 #define __swp_offset(pte_lookalike) ((pte_lookalike).val << 13) 382 383 /* NOPs, to keep generic kernel happy */ 384 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) 385 #define __swp_entry_to_pte(x) ((pte_t) { (x).val }) 386 387 #define kern_addr_valid(addr) (1) 388 389 /* 390 * remap a physical page `pfn' of size `size' with page protection `prot' 391 * into virtual address `from' 392 */ 393 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 394 #include <asm/hugepage.h> 395 #endif 396 397 #include <asm-generic/pgtable.h> 398 399 /* to cope with aliasing VIPT cache */ 400 #define HAVE_ARCH_UNMAPPED_AREA 401 402 /* 403 * No page table caches to initialise 404 */ 405 #define pgtable_cache_init() do { } while (0) 406 407 #endif /* __ASSEMBLY__ */ 408 409 #endif 410