LXR linux/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
  41extern 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
  95extern phys_addr_t memstart_addr;
  96extern phys_addr_t kernstart_addr;
  97
  98#ifdef CONFIG_RELOCATABLE_PPC32
  99extern 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#undef STRICT_MM_TYPECHECKS
 282
 283#ifdef STRICT_MM_TYPECHECKS
 284/* These are used to make use of C type-checking. */
 285
 286/* PTE level */
 287typedef struct { pte_basic_t pte; } pte_t;
 288#define pte_val(x)      ((x).pte)
 289#define __pte(x)        ((pte_t) { (x) })
 290
 291/* 64k pages additionally define a bigger "real PTE" type that gathers
 292 * the "second half" part of the PTE for pseudo 64k pages
 293 */
 294#if defined(CONFIG_PPC_64K_PAGES) && defined(CONFIG_PPC_STD_MMU_64)
 295typedef struct { pte_t pte; unsigned long hidx; } real_pte_t;
 296#else
 297typedef struct { pte_t pte; } real_pte_t;
 298#endif
 299
 300/* PMD level */
 301#ifdef CONFIG_PPC64
 302typedef struct { unsigned long pmd; } pmd_t;
 303#define pmd_val(x)      ((x).pmd)
 304#define __pmd(x)        ((pmd_t) { (x) })
 305
 306/* PUD level exusts only on 4k pages */
 307#ifndef CONFIG_PPC_64K_PAGES
 308typedef struct { unsigned long pud; } pud_t;
 309#define pud_val(x)      ((x).pud)
 310#define __pud(x)        ((pud_t) { (x) })
 311#endif /* !CONFIG_PPC_64K_PAGES */
 312#endif /* CONFIG_PPC64 */
 313
 314/* PGD level */
 315typedef struct { unsigned long pgd; } pgd_t;
 316#define pgd_val(x)      ((x).pgd)
 317#define __pgd(x)        ((pgd_t) { (x) })
 318
 319/* Page protection bits */
 320typedef struct { unsigned long pgprot; } pgprot_t;
 321#define pgprot_val(x)   ((x).pgprot)
 322#define __pgprot(x)     ((pgprot_t) { (x) })
 323
 324#else
 325
 326/*
 327 * .. while these make it easier on the compiler
 328 */
 329
 330typedef pte_basic_t pte_t;
 331#define pte_val(x)      (x)
 332#define __pte(x)        (x)
 333
 334#if defined(CONFIG_PPC_64K_PAGES) && defined(CONFIG_PPC_STD_MMU_64)
 335typedef struct { pte_t pte; unsigned long hidx; } real_pte_t;
 336#else
 337typedef pte_t real_pte_t;
 338#endif
 339
 340
 341#ifdef CONFIG_PPC64
 342typedef unsigned long pmd_t;
 343#define pmd_val(x)      (x)
 344#define __pmd(x)        (x)
 345
 346#ifndef CONFIG_PPC_64K_PAGES
 347typedef unsigned long pud_t;
 348#define pud_val(x)      (x)
 349#define __pud(x)        (x)
 350#endif /* !CONFIG_PPC_64K_PAGES */
 351#endif /* CONFIG_PPC64 */
 352
 353typedef unsigned long pgd_t;
 354#define pgd_val(x)      (x)
 355#define pgprot_val(x)   (x)
 356
 357typedef unsigned long pgprot_t;
 358#define __pgd(x)        (x)
 359#define __pgprot(x)     (x)
 360
 361#endif
 362
 363typedef struct { signed long pd; } hugepd_t;
 364
 365#ifdef CONFIG_HUGETLB_PAGE
 366#ifdef CONFIG_PPC_BOOK3S_64
 367static inline int hugepd_ok(hugepd_t hpd)
 368{
 369        /*
 370         * hugepd pointer, bottom two bits == 00 and next 4 bits
 371         * indicate size of table
 372         */
 373        return (((hpd.pd & 0x3) == 0x0) && ((hpd.pd & HUGEPD_SHIFT_MASK) != 0));
 374}
 375#else
 376static inline int hugepd_ok(hugepd_t hpd)
 377{
 378        return (hpd.pd > 0);
 379}
 380#endif
 381
 382#define is_hugepd(pdep)               (hugepd_ok(*((hugepd_t *)(pdep))))
 383int pgd_huge(pgd_t pgd);
 384#else /* CONFIG_HUGETLB_PAGE */
 385#define is_hugepd(pdep)                 0
 386#define pgd_huge(pgd)                   0
 387#endif /* CONFIG_HUGETLB_PAGE */
 388
 389struct page;
 390extern void clear_user_page(void *page, unsigned long vaddr, struct page *pg);
 391extern void copy_user_page(void *to, void *from, unsigned long vaddr,
 392                struct page *p);
 393extern int page_is_ram(unsigned long pfn);
 394extern int devmem_is_allowed(unsigned long pfn);
 395
 396#ifdef CONFIG_PPC_SMLPAR
 397void arch_free_page(struct page *page, int order);
 398#define HAVE_ARCH_FREE_PAGE
 399#endif
 400
 401struct vm_area_struct;
 402
 403#if defined(CONFIG_PPC_64K_PAGES) && defined(CONFIG_PPC64)
 404typedef pte_t *pgtable_t;
 405#else
 406typedef struct page *pgtable_t;
 407#endif
 408
 409#include <asm-generic/memory_model.h>
 410#endif /* __ASSEMBLY__ */
 411
 412#endif /* _ASM_POWERPC_PAGE_H */
 413