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_MODIFIED (1<<6) /* Page modified (dirty) (S) */ 64 #define _PAGE_GLOBAL (1<<8) /* Page is global (H) */ 65 #define _PAGE_PRESENT (1<<10) /* TLB entry is valid (H) */ 66 67 #else /* MMU v3 onwards */ 68 69 #define _PAGE_CACHEABLE (1<<0) /* Page is cached (H) */ 70 #define _PAGE_EXECUTE (1<<1) /* Page has user execute perm (H) */ 71 #define _PAGE_WRITE (1<<2) /* Page has user write perm (H) */ 72 #define _PAGE_READ (1<<3) /* Page has user read perm (H) */ 73 #define _PAGE_ACCESSED (1<<4) /* Page is accessed (S) */ 74 #define _PAGE_MODIFIED (1<<5) /* Page modified (dirty) (S) */ 75 #define _PAGE_GLOBAL (1<<8) /* Page is global (H) */ 76 #define _PAGE_PRESENT (1<<9) /* TLB entry is valid (H) */ 77 #define _PAGE_SHARED_CODE (1<<11) /* Shared Code page with cmn vaddr 78 usable for shared TLB entries (H) */ 79 #endif 80 81 /* vmalloc permissions */ 82 #define _K_PAGE_PERMS (_PAGE_EXECUTE | _PAGE_WRITE | _PAGE_READ | \ 83 _PAGE_GLOBAL | _PAGE_PRESENT) 84 85 #ifdef CONFIG_ARC_CACHE_PAGES 86 #define _PAGE_DEF_CACHEABLE _PAGE_CACHEABLE 87 #else 88 #define _PAGE_DEF_CACHEABLE (0) 89 #endif 90 91 /* Helper for every "user" page 92 * -kernel can R/W/X 93 * -by default cached, unless config otherwise 94 * -present in memory 95 */ 96 #define ___DEF (_PAGE_PRESENT | _PAGE_DEF_CACHEABLE) 97 98 /* Set of bits not changed in pte_modify */ 99 #define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_MODIFIED) 100 101 /* More Abbrevaited helpers */ 102 #define PAGE_U_NONE __pgprot(___DEF) 103 #define PAGE_U_R __pgprot(___DEF | _PAGE_READ) 104 #define PAGE_U_W_R __pgprot(___DEF | _PAGE_READ | _PAGE_WRITE) 105 #define PAGE_U_X_R __pgprot(___DEF | _PAGE_READ | _PAGE_EXECUTE) 106 #define PAGE_U_X_W_R __pgprot(___DEF | _PAGE_READ | _PAGE_WRITE | \ 107 _PAGE_EXECUTE) 108 109 #define PAGE_SHARED PAGE_U_W_R 110 111 /* While kernel runs out of unstranslated space, vmalloc/modules use a chunk of 112 * user vaddr space - visible in all addr spaces, but kernel mode only 113 * Thus Global, all-kernel-access, no-user-access, cached 114 */ 115 #define PAGE_KERNEL __pgprot(_K_PAGE_PERMS | _PAGE_DEF_CACHEABLE) 116 117 /* ioremap */ 118 #define PAGE_KERNEL_NO_CACHE __pgprot(_K_PAGE_PERMS) 119 120 /* Masks for actual TLB "PD"s */ 121 #define PTE_BITS_IN_PD0 (_PAGE_GLOBAL | _PAGE_PRESENT) 122 #define PTE_BITS_RWX (_PAGE_EXECUTE | _PAGE_WRITE | _PAGE_READ) 123 #define PTE_BITS_NON_RWX_IN_PD1 (PAGE_MASK | _PAGE_CACHEABLE) 124 125 /************************************************************************** 126 * Mapping of vm_flags (Generic VM) to PTE flags (arch specific) 127 * 128 * Certain cases have 1:1 mapping 129 * e.g. __P101 means VM_READ, VM_EXEC and !VM_SHARED 130 * which directly corresponds to PAGE_U_X_R 131 * 132 * Other rules which cause the divergence from 1:1 mapping 133 * 134 * 1. Although ARC700 can do exclusive execute/write protection (meaning R 135 * can be tracked independet of X/W unlike some other CPUs), still to 136 * keep things consistent with other archs: 137 * -Write implies Read: W => R 138 * -Execute implies Read: X => R 139 * 140 * 2. Pvt Writable doesn't have Write Enabled initially: Pvt-W => !W 141 * This is to enable COW mechanism 142 */ 143 /* xwr */ 144 #define __P000 PAGE_U_NONE 145 #define __P001 PAGE_U_R 146 #define __P010 PAGE_U_R /* Pvt-W => !W */ 147 #define __P011 PAGE_U_R /* Pvt-W => !W */ 148 #define __P100 PAGE_U_X_R /* X => R */ 149 #define __P101 PAGE_U_X_R 150 #define __P110 PAGE_U_X_R /* Pvt-W => !W and X => R */ 151 #define __P111 PAGE_U_X_R /* Pvt-W => !W */ 152 153 #define __S000 PAGE_U_NONE 154 #define __S001 PAGE_U_R 155 #define __S010 PAGE_U_W_R /* W => R */ 156 #define __S011 PAGE_U_W_R 157 #define __S100 PAGE_U_X_R /* X => R */ 158 #define __S101 PAGE_U_X_R 159 #define __S110 PAGE_U_X_W_R /* X => R */ 160 #define __S111 PAGE_U_X_W_R 161 162 /**************************************************************** 163 * Page Table Lookup split 164 * 165 * We implement 2 tier paging and since this is all software, we are free 166 * to customize the span of a PGD / PTE entry to suit us 167 * 168 * 32 bit virtual address 169 * ------------------------------------------------------- 170 * | BITS_FOR_PGD | BITS_FOR_PTE | BITS_IN_PAGE | 171 * ------------------------------------------------------- 172 * | | | 173 * | | --> off in page frame 174 * | | 175 * | ---> index into Page Table 176 * | 177 * ----> index into Page Directory 178 */ 179 180 #define BITS_IN_PAGE PAGE_SHIFT 181 182 /* Optimal Sizing of Pg Tbl - based on MMU page size */ 183 #if defined(CONFIG_ARC_PAGE_SIZE_8K) 184 #define BITS_FOR_PTE 8 185 #elif defined(CONFIG_ARC_PAGE_SIZE_16K) 186 #define BITS_FOR_PTE 8 187 #elif defined(CONFIG_ARC_PAGE_SIZE_4K) 188 #define BITS_FOR_PTE 9 189 #endif 190 191 #define BITS_FOR_PGD (32 - BITS_FOR_PTE - BITS_IN_PAGE) 192 193 #define PGDIR_SHIFT (BITS_FOR_PTE + BITS_IN_PAGE) 194 #define PGDIR_SIZE (1UL << PGDIR_SHIFT) /* vaddr span, not PDG sz */ 195 #define PGDIR_MASK (~(PGDIR_SIZE-1)) 196 197 #ifdef __ASSEMBLY__ 198 #define PTRS_PER_PTE (1 << BITS_FOR_PTE) 199 #define PTRS_PER_PGD (1 << BITS_FOR_PGD) 200 #else 201 #define PTRS_PER_PTE (1UL << BITS_FOR_PTE) 202 #define PTRS_PER_PGD (1UL << BITS_FOR_PGD) 203 #endif 204 /* 205 * Number of entries a user land program use. 206 * TASK_SIZE is the maximum vaddr that can be used by a userland program. 207 */ 208 #define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE) 209 210 /* 211 * No special requirements for lowest virtual address we permit any user space 212 * mapping to be mapped at. 213 */ 214 #define FIRST_USER_ADDRESS 0UL 215 216 217 /**************************************************************** 218 * Bucket load of VM Helpers 219 */ 220 221 #ifndef __ASSEMBLY__ 222 223 #define pte_ERROR(e) \ 224 pr_crit("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e)) 225 #define pgd_ERROR(e) \ 226 pr_crit("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e)) 227 228 /* the zero page used for uninitialized and anonymous pages */ 229 extern char empty_zero_page[PAGE_SIZE]; 230 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page)) 231 232 #define pte_unmap(pte) do { } while (0) 233 #define pte_unmap_nested(pte) do { } while (0) 234 235 #define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval)) 236 #define set_pmd(pmdptr, pmdval) (*(pmdptr) = pmdval) 237 238 /* find the page descriptor of the Page Tbl ref by PMD entry */ 239 #define pmd_page(pmd) virt_to_page(pmd_val(pmd) & PAGE_MASK) 240 241 /* find the logical addr (phy for ARC) of the Page Tbl ref by PMD entry */ 242 #define pmd_page_vaddr(pmd) (pmd_val(pmd) & PAGE_MASK) 243 244 /* In a 2 level sys, setup the PGD entry with PTE value */ 245 static inline void pmd_set(pmd_t *pmdp, pte_t *ptep) 246 { 247 pmd_val(*pmdp) = (unsigned long)ptep; 248 } 249 250 #define pte_none(x) (!pte_val(x)) 251 #define pte_present(x) (pte_val(x) & _PAGE_PRESENT) 252 #define pte_clear(mm, addr, ptep) set_pte_at(mm, addr, ptep, __pte(0)) 253 254 #define pmd_none(x) (!pmd_val(x)) 255 #define pmd_bad(x) ((pmd_val(x) & ~PAGE_MASK)) 256 #define pmd_present(x) (pmd_val(x)) 257 #define pmd_clear(xp) do { pmd_val(*(xp)) = 0; } while (0) 258 259 #define pte_page(x) (mem_map + \ 260 (unsigned long)(((pte_val(x) - CONFIG_LINUX_LINK_BASE) >> \ 261 PAGE_SHIFT))) 262 263 #define mk_pte(page, pgprot) \ 264 ({ \ 265 pte_t pte; \ 266 pte_val(pte) = __pa(page_address(page)) + pgprot_val(pgprot); \ 267 pte; \ 268 }) 269 270 #define pte_pfn(pte) (pte_val(pte) >> PAGE_SHIFT) 271 #define pfn_pte(pfn, prot) (__pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot))) 272 #define __pte_index(addr) (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) 273 274 /* 275 * pte_offset gets a @ptr to PMD entry (PGD in our 2-tier paging system) 276 * and returns ptr to PTE entry corresponding to @addr 277 */ 278 #define pte_offset(dir, addr) ((pte_t *)(pmd_page_vaddr(*dir)) +\ 279 __pte_index(addr)) 280 281 /* No mapping of Page Tables in high mem etc, so following same as above */ 282 #define pte_offset_kernel(dir, addr) pte_offset(dir, addr) 283 #define pte_offset_map(dir, addr) pte_offset(dir, addr) 284 285 /* Zoo of pte_xxx function */ 286 #define pte_read(pte) (pte_val(pte) & _PAGE_READ) 287 #define pte_write(pte) (pte_val(pte) & _PAGE_WRITE) 288 #define pte_dirty(pte) (pte_val(pte) & _PAGE_MODIFIED) 289 #define pte_young(pte) (pte_val(pte) & _PAGE_ACCESSED) 290 #define pte_special(pte) (0) 291 292 #define PTE_BIT_FUNC(fn, op) \ 293 static inline pte_t pte_##fn(pte_t pte) { pte_val(pte) op; return pte; } 294 295 PTE_BIT_FUNC(wrprotect, &= ~(_PAGE_WRITE)); 296 PTE_BIT_FUNC(mkwrite, |= (_PAGE_WRITE)); 297 PTE_BIT_FUNC(mkclean, &= ~(_PAGE_MODIFIED)); 298 PTE_BIT_FUNC(mkdirty, |= (_PAGE_MODIFIED)); 299 PTE_BIT_FUNC(mkold, &= ~(_PAGE_ACCESSED)); 300 PTE_BIT_FUNC(mkyoung, |= (_PAGE_ACCESSED)); 301 PTE_BIT_FUNC(exprotect, &= ~(_PAGE_EXECUTE)); 302 PTE_BIT_FUNC(mkexec, |= (_PAGE_EXECUTE)); 303 304 static inline pte_t pte_mkspecial(pte_t pte) { return pte; } 305 306 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) 307 { 308 return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot)); 309 } 310 311 /* Macro to mark a page protection as uncacheable */ 312 #define pgprot_noncached(prot) (__pgprot(pgprot_val(prot) & ~_PAGE_CACHEABLE)) 313 314 static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, 315 pte_t *ptep, pte_t pteval) 316 { 317 set_pte(ptep, pteval); 318 } 319 320 /* 321 * All kernel related VM pages are in init's mm. 322 */ 323 #define pgd_offset_k(address) pgd_offset(&init_mm, address) 324 #define pgd_index(addr) ((addr) >> PGDIR_SHIFT) 325 #define pgd_offset(mm, addr) (((mm)->pgd)+pgd_index(addr)) 326 327 /* 328 * Macro to quickly access the PGD entry, utlising the fact that some 329 * arch may cache the pointer to Page Directory of "current" task 330 * in a MMU register 331 * 332 * Thus task->mm->pgd (3 pointer dereferences, cache misses etc simply 333 * becomes read a register 334 * 335 * ********CAUTION*******: 336 * Kernel code might be dealing with some mm_struct of NON "current" 337 * Thus use this macro only when you are certain that "current" is current 338 * e.g. when dealing with signal frame setup code etc 339 */ 340 #ifndef CONFIG_SMP 341 #define pgd_offset_fast(mm, addr) \ 342 ({ \ 343 pgd_t *pgd_base = (pgd_t *) read_aux_reg(ARC_REG_SCRATCH_DATA0); \ 344 pgd_base + pgd_index(addr); \ 345 }) 346 #else 347 #define pgd_offset_fast(mm, addr) pgd_offset(mm, addr) 348 #endif 349 350 extern void paging_init(void); 351 extern pgd_t swapper_pg_dir[] __aligned(PAGE_SIZE); 352 void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, 353 pte_t *ptep); 354 355 /* Encode swap {type,off} tuple into PTE 356 * We reserve 13 bits for 5-bit @type, keeping bits 12-5 zero, ensuring that 357 * PAGE_PRESENT is zero in a PTE holding swap "identifier" 358 */ 359 #define __swp_entry(type, off) ((swp_entry_t) { \ 360 ((type) & 0x1f) | ((off) << 13) }) 361 362 /* Decode a PTE containing swap "identifier "into constituents */ 363 #define __swp_type(pte_lookalike) (((pte_lookalike).val) & 0x1f) 364 #define __swp_offset(pte_lookalike) ((pte_lookalike).val << 13) 365 366 /* NOPs, to keep generic kernel happy */ 367 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) 368 #define __swp_entry_to_pte(x) ((pte_t) { (x).val }) 369 370 #define kern_addr_valid(addr) (1) 371 372 /* 373 * remap a physical page `pfn' of size `size' with page protection `prot' 374 * into virtual address `from' 375 */ 376 #include <asm-generic/pgtable.h> 377 378 /* to cope with aliasing VIPT cache */ 379 #define HAVE_ARCH_UNMAPPED_AREA 380 381 /* 382 * No page table caches to initialise 383 */ 384 #define pgtable_cache_init() do { } while (0) 385 386 #endif /* __ASSEMBLY__ */ 387 388 #endif 389