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 accomodate 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 42 /************************************************************************** 43 * Page Table Flags 44 * 45 * ARC700 MMU only deals with softare managed TLB entries. 46 * Page Tables are purely for Linux VM's consumption and the bits below are 47 * suited to that (uniqueness). Hence some are not implemented in the TLB and 48 * some have different value in TLB. 49 * e.g. MMU v2: K_READ bit is 8 and so is GLOBAL (possible becoz they live in 50 * seperate PD0 and PD1, which combined forms a translation entry) 51 * while for PTE perspective, they are 8 and 9 respectively 52 * with MMU v3: Most bits (except SHARED) represent the exact hardware pos 53 * (saves some bit shift ops in TLB Miss hdlrs) 54 */ 55 56 #if (CONFIG_ARC_MMU_VER <= 2) 57 58 #define _PAGE_ACCESSED (1<<1) /* Page is accessed (S) */ 59 #define _PAGE_CACHEABLE (1<<2) /* Page is cached (H) */ 60 #define _PAGE_EXECUTE (1<<3) /* Page has user execute perm (H) */ 61 #define _PAGE_WRITE (1<<4) /* Page has user write perm (H) */ 62 #define _PAGE_READ (1<<5) /* Page has user read perm (H) */ 63 #define _PAGE_K_EXECUTE (1<<6) /* Page has kernel execute perm (H) */ 64 #define _PAGE_K_WRITE (1<<7) /* Page has kernel write perm (H) */ 65 #define _PAGE_K_READ (1<<8) /* Page has kernel perm (H) */ 66 #define _PAGE_GLOBAL (1<<9) /* Page is global (H) */ 67 #define _PAGE_MODIFIED (1<<10) /* Page modified (dirty) (S) */ 68 #define _PAGE_FILE (1<<10) /* page cache/ swap (S) */ 69 #define _PAGE_PRESENT (1<<11) /* TLB entry is valid (H) */ 70 71 #else 72 73 /* PD1 */ 74 #define _PAGE_CACHEABLE (1<<0) /* Page is cached (H) */ 75 #define _PAGE_EXECUTE (1<<1) /* Page has user execute perm (H) */ 76 #define _PAGE_WRITE (1<<2) /* Page has user write perm (H) */ 77 #define _PAGE_READ (1<<3) /* Page has user read perm (H) */ 78 #define _PAGE_K_EXECUTE (1<<4) /* Page has kernel execute perm (H) */ 79 #define _PAGE_K_WRITE (1<<5) /* Page has kernel write perm (H) */ 80 #define _PAGE_K_READ (1<<6) /* Page has kernel perm (H) */ 81 #define _PAGE_ACCESSED (1<<7) /* Page is accessed (S) */ 82 83 /* PD0 */ 84 #define _PAGE_GLOBAL (1<<8) /* Page is global (H) */ 85 #define _PAGE_PRESENT (1<<9) /* TLB entry is valid (H) */ 86 #define _PAGE_SHARED_CODE (1<<10) /* Shared Code page with cmn vaddr 87 usable for shared TLB entries (H) */ 88 89 #define _PAGE_MODIFIED (1<<11) /* Page modified (dirty) (S) */ 90 #define _PAGE_FILE (1<<12) /* page cache/ swap (S) */ 91 92 #define _PAGE_SHARED_CODE_H (1<<31) /* Hardware counterpart of above */ 93 #endif 94 95 /* Kernel allowed all permissions for all pages */ 96 #define _K_PAGE_PERMS (_PAGE_K_EXECUTE | _PAGE_K_WRITE | _PAGE_K_READ) 97 98 #ifdef CONFIG_ARC_CACHE_PAGES 99 #define _PAGE_DEF_CACHEABLE _PAGE_CACHEABLE 100 #else 101 #define _PAGE_DEF_CACHEABLE (0) 102 #endif 103 104 /* Helper for every "user" page 105 * -kernel can R/W/X 106 * -by default cached, unless config otherwise 107 * -present in memory 108 */ 109 #define ___DEF (_PAGE_PRESENT | _K_PAGE_PERMS | _PAGE_DEF_CACHEABLE) 110 111 /* Set of bits not changed in pte_modify */ 112 #define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_MODIFIED) 113 114 /* More Abbrevaited helpers */ 115 #define PAGE_U_NONE __pgprot(___DEF) 116 #define PAGE_U_R __pgprot(___DEF | _PAGE_READ) 117 #define PAGE_U_W_R __pgprot(___DEF | _PAGE_READ | _PAGE_WRITE) 118 #define PAGE_U_X_R __pgprot(___DEF | _PAGE_READ | _PAGE_EXECUTE) 119 #define PAGE_U_X_W_R __pgprot(___DEF | _PAGE_READ | _PAGE_WRITE | \ 120 _PAGE_EXECUTE) 121 122 #define PAGE_SHARED PAGE_U_W_R 123 124 /* While kernel runs out of unstrslated space, vmalloc/modules use a chunk of 125 * kernel vaddr space - visible in all addr spaces, but kernel mode only 126 * Thus Global, all-kernel-access, no-user-access, cached 127 */ 128 #define PAGE_KERNEL __pgprot(___DEF | _PAGE_GLOBAL) 129 130 /* ioremap */ 131 #define PAGE_KERNEL_NO_CACHE __pgprot(_PAGE_PRESENT | _K_PAGE_PERMS | \ 132 _PAGE_GLOBAL) 133 134 /************************************************************************** 135 * Mapping of vm_flags (Generic VM) to PTE flags (arch specific) 136 * 137 * Certain cases have 1:1 mapping 138 * e.g. __P101 means VM_READ, VM_EXEC and !VM_SHARED 139 * which directly corresponds to PAGE_U_X_R 140 * 141 * Other rules which cause the divergence from 1:1 mapping 142 * 143 * 1. Although ARC700 can do exclusive execute/write protection (meaning R 144 * can be tracked independet of X/W unlike some other CPUs), still to 145 * keep things consistent with other archs: 146 * -Write implies Read: W => R 147 * -Execute implies Read: X => R 148 * 149 * 2. Pvt Writable doesn't have Write Enabled initially: Pvt-W => !W 150 * This is to enable COW mechanism 151 */ 152 /* xwr */ 153 #define __P000 PAGE_U_NONE 154 #define __P001 PAGE_U_R 155 #define __P010 PAGE_U_R /* Pvt-W => !W */ 156 #define __P011 PAGE_U_R /* Pvt-W => !W */ 157 #define __P100 PAGE_U_X_R /* X => R */ 158 #define __P101 PAGE_U_X_R 159 #define __P110 PAGE_U_X_R /* Pvt-W => !W and X => R */ 160 #define __P111 PAGE_U_X_R /* Pvt-W => !W */ 161 162 #define __S000 PAGE_U_NONE 163 #define __S001 PAGE_U_R 164 #define __S010 PAGE_U_W_R /* W => R */ 165 #define __S011 PAGE_U_W_R 166 #define __S100 PAGE_U_X_R /* X => R */ 167 #define __S101 PAGE_U_X_R 168 #define __S110 PAGE_U_X_W_R /* X => R */ 169 #define __S111 PAGE_U_X_W_R 170 171 /**************************************************************** 172 * Page Table Lookup split 173 * 174 * We implement 2 tier paging and since this is all software, we are free 175 * to customize the span of a PGD / PTE entry to suit us 176 * 177 * 32 bit virtual address 178 * ------------------------------------------------------- 179 * | BITS_FOR_PGD | BITS_FOR_PTE | BITS_IN_PAGE | 180 * ------------------------------------------------------- 181 * | | | 182 * | | --> off in page frame 183 * | | 184 * | ---> index into Page Table 185 * | 186 * ----> index into Page Directory 187 */ 188 189 #define BITS_IN_PAGE PAGE_SHIFT 190 191 /* Optimal Sizing of Pg Tbl - based on MMU page size */ 192 #if defined(CONFIG_ARC_PAGE_SIZE_8K) 193 #define BITS_FOR_PTE 8 194 #elif defined(CONFIG_ARC_PAGE_SIZE_16K) 195 #define BITS_FOR_PTE 8 196 #elif defined(CONFIG_ARC_PAGE_SIZE_4K) 197 #define BITS_FOR_PTE 9 198 #endif 199 200 #define BITS_FOR_PGD (32 - BITS_FOR_PTE - BITS_IN_PAGE) 201 202 #define PGDIR_SHIFT (BITS_FOR_PTE + BITS_IN_PAGE) 203 #define PGDIR_SIZE (1UL << PGDIR_SHIFT) /* vaddr span, not PDG sz */ 204 #define PGDIR_MASK (~(PGDIR_SIZE-1)) 205 206 #ifdef __ASSEMBLY__ 207 #define PTRS_PER_PTE (1 << BITS_FOR_PTE) 208 #define PTRS_PER_PGD (1 << BITS_FOR_PGD) 209 #else 210 #define PTRS_PER_PTE (1UL << BITS_FOR_PTE) 211 #define PTRS_PER_PGD (1UL << BITS_FOR_PGD) 212 #endif 213 /* 214 * Number of entries a user land program use. 215 * TASK_SIZE is the maximum vaddr that can be used by a userland program. 216 */ 217 #define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE) 218 219 /* 220 * No special requirements for lowest virtual address we permit any user space 221 * mapping to be mapped at. 222 */ 223 #define FIRST_USER_ADDRESS 0 224 225 226 /**************************************************************** 227 * Bucket load of VM Helpers 228 */ 229 230 #ifndef __ASSEMBLY__ 231 232 #define pte_ERROR(e) \ 233 pr_crit("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e)) 234 #define pgd_ERROR(e) \ 235 pr_crit("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e)) 236 237 /* the zero page used for uninitialized and anonymous pages */ 238 extern char empty_zero_page[PAGE_SIZE]; 239 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page)) 240 241 #define pte_unmap(pte) do { } while (0) 242 #define pte_unmap_nested(pte) do { } while (0) 243 244 #define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval)) 245 #define set_pmd(pmdptr, pmdval) (*(pmdptr) = pmdval) 246 247 /* find the page descriptor of the Page Tbl ref by PMD entry */ 248 #define pmd_page(pmd) virt_to_page(pmd_val(pmd) & PAGE_MASK) 249 250 /* find the logical addr (phy for ARC) of the Page Tbl ref by PMD entry */ 251 #define pmd_page_vaddr(pmd) (pmd_val(pmd) & PAGE_MASK) 252 253 /* In a 2 level sys, setup the PGD entry with PTE value */ 254 static inline void pmd_set(pmd_t *pmdp, pte_t *ptep) 255 { 256 pmd_val(*pmdp) = (unsigned long)ptep; 257 } 258 259 #define pte_none(x) (!pte_val(x)) 260 #define pte_present(x) (pte_val(x) & _PAGE_PRESENT) 261 #define pte_clear(mm, addr, ptep) set_pte_at(mm, addr, ptep, __pte(0)) 262 263 #define pmd_none(x) (!pmd_val(x)) 264 #define pmd_bad(x) ((pmd_val(x) & ~PAGE_MASK)) 265 #define pmd_present(x) (pmd_val(x)) 266 #define pmd_clear(xp) do { pmd_val(*(xp)) = 0; } while (0) 267 268 #define pte_page(x) (mem_map + \ 269 (unsigned long)(((pte_val(x) - PAGE_OFFSET) >> PAGE_SHIFT))) 270 271 #define mk_pte(page, pgprot) \ 272 ({ \ 273 pte_t pte; \ 274 pte_val(pte) = __pa(page_address(page)) + pgprot_val(pgprot); \ 275 pte; \ 276 }) 277 278 /* TBD: Non linear mapping stuff */ 279 static inline int pte_file(pte_t pte) 280 { 281 return pte_val(pte) & _PAGE_FILE; 282 } 283 284 #define PTE_FILE_MAX_BITS 30 285 #define pgoff_to_pte(x) __pte(x) 286 #define pte_to_pgoff(x) (pte_val(x) >> 2) 287 #define pte_pfn(pte) (pte_val(pte) >> PAGE_SHIFT) 288 #define pfn_pte(pfn, prot) (__pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot))) 289 #define __pte_index(addr) (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) 290 291 /* 292 * pte_offset gets a @ptr to PMD entry (PGD in our 2-tier paging system) 293 * and returns ptr to PTE entry corresponding to @addr 294 */ 295 #define pte_offset(dir, addr) ((pte_t *)(pmd_page_vaddr(*dir)) +\ 296 __pte_index(addr)) 297 298 /* No mapping of Page Tables in high mem etc, so following same as above */ 299 #define pte_offset_kernel(dir, addr) pte_offset(dir, addr) 300 #define pte_offset_map(dir, addr) pte_offset(dir, addr) 301 302 /* Zoo of pte_xxx function */ 303 #define pte_read(pte) (pte_val(pte) & _PAGE_READ) 304 #define pte_write(pte) (pte_val(pte) & _PAGE_WRITE) 305 #define pte_dirty(pte) (pte_val(pte) & _PAGE_MODIFIED) 306 #define pte_young(pte) (pte_val(pte) & _PAGE_ACCESSED) 307 #define pte_special(pte) (0) 308 309 #define PTE_BIT_FUNC(fn, op) \ 310 static inline pte_t pte_##fn(pte_t pte) { pte_val(pte) op; return pte; } 311 312 PTE_BIT_FUNC(wrprotect, &= ~(_PAGE_WRITE)); 313 PTE_BIT_FUNC(mkwrite, |= (_PAGE_WRITE)); 314 PTE_BIT_FUNC(mkclean, &= ~(_PAGE_MODIFIED)); 315 PTE_BIT_FUNC(mkdirty, |= (_PAGE_MODIFIED)); 316 PTE_BIT_FUNC(mkold, &= ~(_PAGE_ACCESSED)); 317 PTE_BIT_FUNC(mkyoung, |= (_PAGE_ACCESSED)); 318 PTE_BIT_FUNC(exprotect, &= ~(_PAGE_EXECUTE)); 319 PTE_BIT_FUNC(mkexec, |= (_PAGE_EXECUTE)); 320 321 static inline pte_t pte_mkspecial(pte_t pte) { return pte; } 322 323 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) 324 { 325 return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot)); 326 } 327 328 /* Macro to mark a page protection as uncacheable */ 329 #define pgprot_noncached(prot) (__pgprot(pgprot_val(prot) & ~_PAGE_CACHEABLE)) 330 331 static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, 332 pte_t *ptep, pte_t pteval) 333 { 334 set_pte(ptep, pteval); 335 } 336 337 /* 338 * All kernel related VM pages are in init's mm. 339 */ 340 #define pgd_offset_k(address) pgd_offset(&init_mm, address) 341 #define pgd_index(addr) ((addr) >> PGDIR_SHIFT) 342 #define pgd_offset(mm, addr) (((mm)->pgd)+pgd_index(addr)) 343 344 /* 345 * Macro to quickly access the PGD entry, utlising the fact that some 346 * arch may cache the pointer to Page Directory of "current" task 347 * in a MMU register 348 * 349 * Thus task->mm->pgd (3 pointer dereferences, cache misses etc simply 350 * becomes read a register 351 * 352 * ********CAUTION*******: 353 * Kernel code might be dealing with some mm_struct of NON "current" 354 * Thus use this macro only when you are certain that "current" is current 355 * e.g. when dealing with signal frame setup code etc 356 */ 357 #ifndef CONFIG_SMP 358 #define pgd_offset_fast(mm, addr) \ 359 ({ \ 360 pgd_t *pgd_base = (pgd_t *) read_aux_reg(ARC_REG_SCRATCH_DATA0); \ 361 pgd_base + pgd_index(addr); \ 362 }) 363 #else 364 #define pgd_offset_fast(mm, addr) pgd_offset(mm, addr) 365 #endif 366 367 extern void paging_init(void); 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 * both PAGE_FILE and PAGE_PRESENT are 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 #define io_remap_pfn_range(vma, from, pfn, size, prot) \ 394 remap_pfn_range(vma, from, pfn, size, prot) 395 396 #include <asm-generic/pgtable.h> 397 398 /* to cope with aliasing VIPT cache */ 399 #define HAVE_ARCH_UNMAPPED_AREA 400 401 /* 402 * No page table caches to initialise 403 */ 404 #define pgtable_cache_init() do { } while (0) 405 406 #endif /* __ASSEMBLY__ */ 407 408 #endif 409