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/* 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
  98extern phys_addr_t memstart_addr;
  99extern phys_addr_t kernstart_addr;
 100
 101#ifdef CONFIG_RELOCATABLE_PPC32
 102extern 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 */
 278typedef 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)
 286typedef struct { pte_t pte; unsigned long hidx; } real_pte_t;
 287#else
 288typedef struct { pte_t pte; } real_pte_t;
 289#endif
 290
 291/* PMD level */
 292#ifdef CONFIG_PPC64
 293typedef 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
 299typedef 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 */
 306typedef 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 */
 311typedef 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
 321typedef 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)
 326typedef struct { pte_t pte; unsigned long hidx; } real_pte_t;
 327#else
 328typedef pte_t real_pte_t;
 329#endif
 330
 331
 332#ifdef CONFIG_PPC64
 333typedef unsigned long pmd_t;
 334#define pmd_val(x)      (x)
 335#define __pmd(x)        (x)
 336
 337#ifndef CONFIG_PPC_64K_PAGES
 338typedef 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
 344typedef unsigned long pgd_t;
 345#define pgd_val(x)      (x)
 346#define pgprot_val(x)   (x)
 347
 348typedef unsigned long pgprot_t;
 349#define __pgd(x)        (x)
 350#define __pgprot(x)     (x)
 351
 352#endif
 353
 354typedef struct { signed long pd; } hugepd_t;
 355
 356#ifdef CONFIG_HUGETLB_PAGE
 357static 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
 367struct page;
 368extern void clear_user_page(void *page, unsigned long vaddr, struct page *pg);
 369extern void copy_user_page(void *to, void *from, unsigned long vaddr,
 370                struct page *p);
 371extern int page_is_ram(unsigned long pfn);
 372extern int devmem_is_allowed(unsigned long pfn);
 373
 374#ifdef CONFIG_PPC_SMLPAR
 375void arch_free_page(struct page *page, int order);
 376#define HAVE_ARCH_FREE_PAGE
 377#endif
 378
 379struct vm_area_struct;
 380
 381typedef struct page *pgtable_t;
 382
 383#include <asm-generic/memory_model.h>
 384#endif /* __ASSEMBLY__ */
 385
 386#endif /* _ASM_POWERPC_PAGE_H */
 387