arch/powerpc/include/asm/page.h

   1 #ifndef _ASM_POWERPC_PAGE_H
   2 #define _ASM_POWERPC_PAGE_H
   3
   4 /*
   5  * Copyright (C) 2001,2005 IBM Corporation.
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version
  10  * 2 of the License, or (at your option) any later version.
  11  */
  12
  13 #ifndef __ASSEMBLY__
  14 #include <linux/types.h>
  15 #else
  16 #include <asm/types.h>
  17 #endif
  18 #include <asm/asm-compat.h>
  19 #include <asm/kdump.h>
  20
  21 /*
  22  * On regular PPC32 page size is 4K (but we support 4K/16K/64K/256K pages
  23  * on PPC44x). For PPC64 we support either 4K or 64K software
  24  * page size. When using 64K pages however, whether we are really supporting
  25  * 64K pages in HW or not is irrelevant to those definitions.
  26  */
  27 #if defined(CONFIG_PPC_256K_PAGES)
  28 #define PAGE_SHIFT              18
  29 #elif defined(CONFIG_PPC_64K_PAGES)
  30 #define PAGE_SHIFT              16
  31 #elif defined(CONFIG_PPC_16K_PAGES)
  32 #define PAGE_SHIFT              14
  33 #else
  34 #define PAGE_SHIFT              12
  35 #endif
  36
  37 #define PAGE_SIZE               (ASM_CONST(1) << PAGE_SHIFT)
  38
  39 #ifndef __ASSEMBLY__
  40 #ifdef CONFIG_HUGETLB_PAGE
  41 extern unsigned int HPAGE_SHIFT;
  42 #else
  43 #define HPAGE_SHIFT PAGE_SHIFT
  44 #endif
  45 #define HPAGE_SIZE              ((1UL) << HPAGE_SHIFT)
  46 #define HPAGE_MASK              (~(HPAGE_SIZE - 1))
  47 #define HUGETLB_PAGE_ORDER      (HPAGE_SHIFT - PAGE_SHIFT)
  48 #define HUGE_MAX_HSTATE         (MMU_PAGE_COUNT-1)
  49 #endif
  50
  51 /*
  52  * Subtle: (1 << PAGE_SHIFT) is an int, not an unsigned long. So if we
  53  * assign PAGE_MASK to a larger type it gets extended the way we want
  54  * (i.e. with 1s in the high bits)
  55  */
  56 #define PAGE_MASK      (~((1 << PAGE_SHIFT) - 1))
  57
  58 /*
  59  * KERNELBASE is the virtual address of the start of the kernel, it's often
  60  * the same as PAGE_OFFSET, but _might not be_.
  61  *
  62  * The kdump dump kernel is one example where KERNELBASE != PAGE_OFFSET.
  63  *
  64  * PAGE_OFFSET is the virtual address of the start of lowmem.
  65  *
  66  * PHYSICAL_START is the physical address of the start of the kernel.
  67  *
  68  * MEMORY_START is the physical address of the start of lowmem.
  69  *
  70  * KERNELBASE, PAGE_OFFSET, and PHYSICAL_START are all configurable on
  71  * ppc32 and based on how they are set we determine MEMORY_START.
  72  *
  73  * For the linear mapping the following equation should be true:
  74  * KERNELBASE - PAGE_OFFSET = PHYSICAL_START - MEMORY_START
  75  *
  76  * Also, KERNELBASE >= PAGE_OFFSET and PHYSICAL_START >= MEMORY_START
  77  *
  78  * There are two ways to determine a physical address from a virtual one:
  79  * va = pa + PAGE_OFFSET - MEMORY_START
  80  * va = pa + KERNELBASE - PHYSICAL_START
  81  *
  82  * If you want to know something's offset from the start of the kernel you
  83  * should subtract KERNELBASE.
  84  *
  85  * If you want to test if something's a kernel address, use is_kernel_addr().
  86  */
  87
  88 #define KERNELBASE      ASM_CONST(CONFIG_KERNEL_START)
  89 #define PAGE_OFFSET     ASM_CONST(CONFIG_PAGE_OFFSET)
  90 #define LOAD_OFFSET     ASM_CONST((CONFIG_KERNEL_START-CONFIG_PHYSICAL_START))
  91
  92 #if defined(CONFIG_NONSTATIC_KERNEL)
  93 #ifndef __ASSEMBLY__
  94
  95 extern phys_addr_t memstart_addr;
  96 extern phys_addr_t kernstart_addr;
  97
  98 #ifdef CONFIG_RELOCATABLE_PPC32
  99 extern long long virt_phys_offset;
 100 #endif
 101
 102 #endif /* __ASSEMBLY__ */
 103 #define PHYSICAL_START  kernstart_addr
 104
 105 #else   /* !CONFIG_NONSTATIC_KERNEL */
 106 #define PHYSICAL_START  ASM_CONST(CONFIG_PHYSICAL_START)
 107 #endif
 108
 109 /* See Description below for VIRT_PHYS_OFFSET */
 110 #ifdef CONFIG_RELOCATABLE_PPC32
 111 #define VIRT_PHYS_OFFSET virt_phys_offset
 112 #else
 113 #define VIRT_PHYS_OFFSET (KERNELBASE - PHYSICAL_START)
 114 #endif
 115
 116
 117 #ifdef CONFIG_PPC64
 118 #define MEMORY_START    0UL
 119 #elif defined(CONFIG_NONSTATIC_KERNEL)
 120 #define MEMORY_START    memstart_addr
 121 #else
 122 #define MEMORY_START    (PHYSICAL_START + PAGE_OFFSET - KERNELBASE)
 123 #endif
 124
 125 #ifdef CONFIG_FLATMEM
 126 #define ARCH_PFN_OFFSET         ((unsigned long)(MEMORY_START >> PAGE_SHIFT))
 127 #define pfn_valid(pfn)          ((pfn) >= ARCH_PFN_OFFSET && (pfn) < max_mapnr)
 128 #endif
 129
 130 #define virt_to_page(kaddr)     pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
 131 #define pfn_to_kaddr(pfn)       __va((pfn) << PAGE_SHIFT)
 132 #define virt_addr_valid(kaddr)  pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
 133
 134 /*
 135  * On Book-E parts we need __va to parse the device tree and we can't
 136  * determine MEMORY_START until then.  However we can determine PHYSICAL_START
 137  * from information at hand (program counter, TLB lookup).
 138  *
 139  * On BookE with RELOCATABLE (RELOCATABLE_PPC32)
 140  *
 141  *   With RELOCATABLE_PPC32,  we support loading the kernel at any physical
 142  *   address without any restriction on the page alignment.
 143  *
 144  *   We find the runtime address of _stext and relocate ourselves based on
 145  *   the following calculation:
 146  *
 147  *        virtual_base = ALIGN_DOWN(KERNELBASE,256M) +
 148  *                              MODULO(_stext.run,256M)
 149  *   and create the following mapping:
 150  *
 151  *        ALIGN_DOWN(_stext.run,256M) => ALIGN_DOWN(KERNELBASE,256M)
 152  *
 153  *   When we process relocations, we cannot depend on the
 154  *   existing equation for the __va()/__pa() translations:
 155  *
 156  *         __va(x) = (x)  - PHYSICAL_START + KERNELBASE
 157  *
 158  *   Where:
 159  *       PHYSICAL_START = kernstart_addr = Physical address of _stext
 160  *       KERNELBASE = Compiled virtual address of _stext.
 161  *
 162  *   This formula holds true iff, kernel load address is TLB page aligned.
 163  *
 164  *   In our case, we need to also account for the shift in the kernel Virtual
 165  *   address.
 166  *
 167  *   E.g.,
 168  *
 169  *   Let the kernel be loaded at 64MB and KERNELBASE be 0xc0000000 (same as PAGE_OFFSET).
 170  *   In this case, we would be mapping 0 to 0xc0000000, and kernstart_addr = 64M
 171  *
 172  *   Now __va(1MB) = (0x100000) - (0x4000000) + 0xc0000000
 173  *                 = 0xbc100000 , which is wrong.
 174  *
 175  *   Rather, it should be : 0xc0000000 + 0x100000 = 0xc0100000
 176  *              according to our mapping.
 177  *
 178  *   Hence we use the following formula to get the translations right:
 179  *
 180  *        __va(x) = (x) - [ PHYSICAL_START - Effective KERNELBASE ]
 181  *
 182  *        Where :
 183  *              PHYSICAL_START = dynamic load address.(kernstart_addr variable)
 184  *              Effective KERNELBASE = virtual_base =
 185  *                                   = ALIGN_DOWN(KERNELBASE,256M) +
 186  *                                              MODULO(PHYSICAL_START,256M)
 187  *
 188  *      To make the cost of __va() / __pa() more light weight, we introduce
 189  *      a new variable virt_phys_offset, which will hold :
 190  *
 191  *      virt_phys_offset = Effective KERNELBASE - PHYSICAL_START
 192  *                       = ALIGN_DOWN(KERNELBASE,256M) -
 193  *                              ALIGN_DOWN(PHYSICALSTART,256M)
 194  *
 195  *      Hence :
 196  *
 197  *      __va(x) = x - PHYSICAL_START + Effective KERNELBASE
 198  *              = x + virt_phys_offset
 199  *
 200  *              and
 201  *      __pa(x) = x + PHYSICAL_START - Effective KERNELBASE
 202  *              = x - virt_phys_offset
 203  *
 204  * On non-Book-E PPC64 PAGE_OFFSET and MEMORY_START are constants so use
 205  * the other definitions for __va & __pa.
 206  */
 207 #ifdef CONFIG_BOOKE
 208 #define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + VIRT_PHYS_OFFSET))
 209 #define __pa(x) ((unsigned long)(x) - VIRT_PHYS_OFFSET)
 210 #else
 211 #ifdef CONFIG_PPC64
 212 /*
 213  * gcc miscompiles (unsigned long)(&static_var) - PAGE_OFFSET
 214  * with -mcmodel=medium, so we use & and | instead of - and + on 64-bit.
 215  */
 216 #define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) | PAGE_OFFSET))
 217 #define __pa(x) ((unsigned long)(x) & 0x0fffffffffffffffUL)
 218
 219 #else /* 32-bit, non book E */
 220 #define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + PAGE_OFFSET - MEMORY_START))
 221 #define __pa(x) ((unsigned long)(x) - PAGE_OFFSET + MEMORY_START)
 222 #endif
 223 #endif
 224
 225 /*
 226  * Unfortunately the PLT is in the BSS in the PPC32 ELF ABI,
 227  * and needs to be executable.  This means the whole heap ends
 228  * up being executable.
 229  */
 230 #define VM_DATA_DEFAULT_FLAGS32 (VM_READ | VM_WRITE | VM_EXEC | \
 231                                  VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
 232
 233 #define VM_DATA_DEFAULT_FLAGS64 (VM_READ | VM_WRITE | \
 234                                  VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
 235
 236 #ifdef __powerpc64__
 237 #include <asm/page_64.h>
 238 #else
 239 #include <asm/page_32.h>
 240 #endif
 241
 242 /* align addr on a size boundary - adjust address up/down if needed */
 243 #define _ALIGN_UP(addr,size)    (((addr)+((size)-1))&(~((size)-1)))
 244 #define _ALIGN_DOWN(addr,size)  ((addr)&(~((size)-1)))
 245
 246 /* align addr on a size boundary - adjust address up if needed */
 247 #define _ALIGN(addr,size)     _ALIGN_UP(addr,size)
 248
 249 /*
 250  * Don't compare things with KERNELBASE or PAGE_OFFSET to test for
 251  * "kernelness", use is_kernel_addr() - it should do what you want.
 252  */
 253 #ifdef CONFIG_PPC_BOOK3E_64
 254 #define is_kernel_addr(x)       ((x) >= 0x8000000000000000ul)
 255 #else
 256 #define is_kernel_addr(x)       ((x) >= PAGE_OFFSET)
 257 #endif
 258
 259 #ifndef CONFIG_PPC_BOOK3S_64
 260 /*
 261  * Use the top bit of the higher-level page table entries to indicate whether
 262  * the entries we point to contain hugepages.  This works because we know that
 263  * the page tables live in kernel space.  If we ever decide to support having
 264  * page tables at arbitrary addresses, this breaks and will have to change.
 265  */
 266 #ifdef CONFIG_PPC64
 267 #define PD_HUGE 0x8000000000000000
 268 #else
 269 #define PD_HUGE 0x80000000
 270 #endif
 271 #endif /* CONFIG_PPC_BOOK3S_64 */
 272
 273 /*
 274  * Some number of bits at the level of the page table that points to
 275  * a hugepte are used to encode the size.  This masks those bits.
 276  */
 277 #define HUGEPD_SHIFT_MASK     0x3f
 278
 279 #ifndef __ASSEMBLY__
 280
 281 #ifdef CONFIG_STRICT_MM_TYPECHECKS
 282 /* These are used to make use of C type-checking. */
 283
 284 /* PTE level */
 285 typedef struct { pte_basic_t pte; } pte_t;
 286 #define pte_val(x)      ((x).pte)
 287 #define __pte(x)        ((pte_t) { (x) })
 288
 289 /* 64k pages additionally define a bigger "real PTE" type that gathers
 290  * the "second half" part of the PTE for pseudo 64k pages
 291  */
 292 #if defined(CONFIG_PPC_64K_PAGES) && defined(CONFIG_PPC_STD_MMU_64)
 293 typedef struct { pte_t pte; unsigned long hidx; } real_pte_t;
 294 #else
 295 typedef struct { pte_t pte; } real_pte_t;
 296 #endif
 297
 298 /* PMD level */
 299 #ifdef CONFIG_PPC64
 300 typedef struct { unsigned long pmd; } pmd_t;
 301 #define pmd_val(x)      ((x).pmd)
 302 #define __pmd(x)        ((pmd_t) { (x) })
 303
 304 /* PUD level exusts only on 4k pages */
 305 #ifndef CONFIG_PPC_64K_PAGES
 306 typedef struct { unsigned long pud; } pud_t;
 307 #define pud_val(x)      ((x).pud)
 308 #define __pud(x)        ((pud_t) { (x) })
 309 #endif /* !CONFIG_PPC_64K_PAGES */
 310 #endif /* CONFIG_PPC64 */
 311
 312 /* PGD level */
 313 typedef struct { unsigned long pgd; } pgd_t;
 314 #define pgd_val(x)      ((x).pgd)
 315 #define __pgd(x)        ((pgd_t) { (x) })
 316
 317 /* Page protection bits */
 318 typedef struct { unsigned long pgprot; } pgprot_t;
 319 #define pgprot_val(x)   ((x).pgprot)
 320 #define __pgprot(x)     ((pgprot_t) { (x) })
 321
 322 #else
 323
 324 /*
 325  * .. while these make it easier on the compiler
 326  */
 327
 328 typedef pte_basic_t pte_t;
 329 #define pte_val(x)      (x)
 330 #define __pte(x)        (x)
 331
 332 #if defined(CONFIG_PPC_64K_PAGES) && defined(CONFIG_PPC_STD_MMU_64)
 333 typedef struct { pte_t pte; unsigned long hidx; } real_pte_t;
 334 #else
 335 typedef pte_t real_pte_t;
 336 #endif
 337
 338
 339 #ifdef CONFIG_PPC64
 340 typedef unsigned long pmd_t;
 341 #define pmd_val(x)      (x)
 342 #define __pmd(x)        (x)
 343
 344 #ifndef CONFIG_PPC_64K_PAGES
 345 typedef unsigned long pud_t;
 346 #define pud_val(x)      (x)
 347 #define __pud(x)        (x)
 348 #endif /* !CONFIG_PPC_64K_PAGES */
 349 #endif /* CONFIG_PPC64 */
 350
 351 typedef unsigned long pgd_t;
 352 #define pgd_val(x)      (x)
 353 #define pgprot_val(x)   (x)
 354
 355 typedef unsigned long pgprot_t;
 356 #define __pgd(x)        (x)
 357 #define __pgprot(x)     (x)
 358
 359 #endif
 360
 361 typedef struct { signed long pd; } hugepd_t;
 362
 363 #ifdef CONFIG_HUGETLB_PAGE
 364 #ifdef CONFIG_PPC_BOOK3S_64
 365 static inline int hugepd_ok(hugepd_t hpd)
 366 {
 367         /*
 368          * hugepd pointer, bottom two bits == 00 and next 4 bits
 369          * indicate size of table
 370          */
 371         return (((hpd.pd & 0x3) == 0x0) && ((hpd.pd & HUGEPD_SHIFT_MASK) != 0));
 372 }
 373 #else
 374 static inline int hugepd_ok(hugepd_t hpd)
 375 {
 376         return (hpd.pd > 0);
 377 }
 378 #endif
 379
 380 #define is_hugepd(hpd)               (hugepd_ok(hpd))
 381 #define pgd_huge pgd_huge
 382 int pgd_huge(pgd_t pgd);
 383 #else /* CONFIG_HUGETLB_PAGE */
 384 #define is_hugepd(pdep)                 0
 385 #define pgd_huge(pgd)                   0
 386 #endif /* CONFIG_HUGETLB_PAGE */
 387 #define __hugepd(x) ((hugepd_t) { (x) })
 388
 389 struct page;
 390 extern void clear_user_page(void *page, unsigned long vaddr, struct page *pg);
 391 extern void copy_user_page(void *to, void *from, unsigned long vaddr,
 392                 struct page *p);
 393 extern int page_is_ram(unsigned long pfn);
 394 extern int devmem_is_allowed(unsigned long pfn);
 395
 396 #ifdef CONFIG_PPC_SMLPAR
 397 void arch_free_page(struct page *page, int order);
 398 #define HAVE_ARCH_FREE_PAGE
 399 #endif
 400
 401 struct vm_area_struct;
 402
 403 #if defined(CONFIG_PPC_64K_PAGES) && defined(CONFIG_PPC64)
 404 typedef pte_t *pgtable_t;
 405 #else
 406 typedef struct page *pgtable_t;
 407 #endif
 408
 409 #include <asm-generic/memory_model.h>
 410 #endif /* __ASSEMBLY__ */
 411
 412 #endif /* _ASM_POWERPC_PAGE_H */