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