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 #include <linux/kernel.h>
  16 #else
  17 #include <asm/types.h>
  18 #endif
  19 #include <asm/asm-compat.h>
  20 #include <asm/kdump.h>
  21
  22 /*
  23  * On regular PPC32 page size is 4K (but we support 4K/16K/64K/256K pages
  24  * on PPC44x). For PPC64 we support either 4K or 64K software
  25  * page size. When using 64K pages however, whether we are really supporting
  26  * 64K pages in HW or not is irrelevant to those definitions.
  27  */
  28 #if defined(CONFIG_PPC_256K_PAGES)
  29 #define PAGE_SHIFT              18
  30 #elif defined(CONFIG_PPC_64K_PAGES)
  31 #define PAGE_SHIFT              16
  32 #elif defined(CONFIG_PPC_16K_PAGES)
  33 #define PAGE_SHIFT              14
  34 #else
  35 #define PAGE_SHIFT              12
  36 #endif
  37
  38 #define PAGE_SIZE               (ASM_CONST(1) << PAGE_SHIFT)
  39
  40 #ifndef __ASSEMBLY__
  41 #ifdef CONFIG_HUGETLB_PAGE
  42 extern unsigned int HPAGE_SHIFT;
  43 #else
  44 #define HPAGE_SHIFT PAGE_SHIFT
  45 #endif
  46 #define HPAGE_SIZE              ((1UL) << HPAGE_SHIFT)
  47 #define HPAGE_MASK              (~(HPAGE_SIZE - 1))
  48 #define HUGETLB_PAGE_ORDER      (HPAGE_SHIFT - PAGE_SHIFT)
  49 #define HUGE_MAX_HSTATE         (MMU_PAGE_COUNT-1)
  50 #endif
  51
  52 /*
  53  * Subtle: (1 << PAGE_SHIFT) is an int, not an unsigned long. So if we
  54  * assign PAGE_MASK to a larger type it gets extended the way we want
  55  * (i.e. with 1s in the high bits)
  56  */
  57 #define PAGE_MASK      (~((1 << PAGE_SHIFT) - 1))
  58
  59 /*
  60  * KERNELBASE is the virtual address of the start of the kernel, it's often
  61  * the same as PAGE_OFFSET, but _might not be_.
  62  *
  63  * The kdump dump kernel is one example where KERNELBASE != PAGE_OFFSET.
  64  *
  65  * PAGE_OFFSET is the virtual address of the start of lowmem.
  66  *
  67  * PHYSICAL_START is the physical address of the start of the kernel.
  68  *
  69  * MEMORY_START is the physical address of the start of lowmem.
  70  *
  71  * KERNELBASE, PAGE_OFFSET, and PHYSICAL_START are all configurable on
  72  * ppc32 and based on how they are set we determine MEMORY_START.
  73  *
  74  * For the linear mapping the following equation should be true:
  75  * KERNELBASE - PAGE_OFFSET = PHYSICAL_START - MEMORY_START
  76  *
  77  * Also, KERNELBASE >= PAGE_OFFSET and PHYSICAL_START >= MEMORY_START
  78  *
  79  * There are two ways to determine a physical address from a virtual one:
  80  * va = pa + PAGE_OFFSET - MEMORY_START
  81  * va = pa + KERNELBASE - PHYSICAL_START
  82  *
  83  * If you want to know something's offset from the start of the kernel you
  84  * should subtract KERNELBASE.
  85  *
  86  * If you want to test if something's a kernel address, use is_kernel_addr().
  87  */
  88
  89 #define KERNELBASE      ASM_CONST(CONFIG_KERNEL_START)
  90 #define PAGE_OFFSET     ASM_CONST(CONFIG_PAGE_OFFSET)
  91 #define LOAD_OFFSET     ASM_CONST((CONFIG_KERNEL_START-CONFIG_PHYSICAL_START))
  92
  93 #if defined(CONFIG_NONSTATIC_KERNEL)
  94 #ifndef __ASSEMBLY__
  95
  96 extern phys_addr_t memstart_addr;
  97 extern phys_addr_t kernstart_addr;
  98
  99 #if defined(CONFIG_RELOCATABLE) && defined(CONFIG_PPC32)
 100 extern long long virt_phys_offset;
 101 #endif
 102
 103 #endif /* __ASSEMBLY__ */
 104 #define PHYSICAL_START  kernstart_addr
 105
 106 #else   /* !CONFIG_NONSTATIC_KERNEL */
 107 #define PHYSICAL_START  ASM_CONST(CONFIG_PHYSICAL_START)
 108 #endif
 109
 110 /* See Description below for VIRT_PHYS_OFFSET */
 111 #if defined(CONFIG_PPC32) && defined(CONFIG_BOOKE)
 112 #ifdef CONFIG_RELOCATABLE
 113 #define VIRT_PHYS_OFFSET virt_phys_offset
 114 #else
 115 #define VIRT_PHYS_OFFSET (KERNELBASE - PHYSICAL_START)
 116 #endif
 117 #endif
 118
 119 #ifdef CONFIG_PPC64
 120 #define MEMORY_START    0UL
 121 #elif defined(CONFIG_NONSTATIC_KERNEL)
 122 #define MEMORY_START    memstart_addr
 123 #else
 124 #define MEMORY_START    (PHYSICAL_START + PAGE_OFFSET - KERNELBASE)
 125 #endif
 126
 127 #ifdef CONFIG_FLATMEM
 128 #define ARCH_PFN_OFFSET         ((unsigned long)(MEMORY_START >> PAGE_SHIFT))
 129 #define pfn_valid(pfn)          ((pfn) >= ARCH_PFN_OFFSET && (pfn) < max_mapnr)
 130 #endif
 131
 132 #define virt_to_pfn(kaddr)      (__pa(kaddr) >> PAGE_SHIFT)
 133 #define virt_to_page(kaddr)     pfn_to_page(virt_to_pfn(kaddr))
 134 #define pfn_to_kaddr(pfn)       __va((pfn) << PAGE_SHIFT)
 135 #define virt_addr_valid(kaddr)  pfn_valid(virt_to_pfn(kaddr))
 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 && 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 #if defined(CONFIG_PPC32) && defined(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 #ifdef CONFIG_PPC64
 215 /*
 216  * gcc miscompiles (unsigned long)(&static_var) - PAGE_OFFSET
 217  * with -mcmodel=medium, so we use & and | instead of - and + on 64-bit.
 218  */
 219 #define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) | PAGE_OFFSET))
 220 #define __pa(x) ((unsigned long)(x) & 0x0fffffffffffffffUL)
 221
 222 #else /* 32-bit, non book E */
 223 #define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + PAGE_OFFSET - MEMORY_START))
 224 #define __pa(x) ((unsigned long)(x) - PAGE_OFFSET + MEMORY_START)
 225 #endif
 226 #endif
 227
 228 /*
 229  * Unfortunately the PLT is in the BSS in the PPC32 ELF ABI,
 230  * and needs to be executable.  This means the whole heap ends
 231  * up being executable.
 232  */
 233 #define VM_DATA_DEFAULT_FLAGS32 (VM_READ | VM_WRITE | VM_EXEC | \
 234                                  VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
 235
 236 #define VM_DATA_DEFAULT_FLAGS64 (VM_READ | VM_WRITE | \
 237                                  VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
 238
 239 #ifdef __powerpc64__
 240 #include <asm/page_64.h>
 241 #else
 242 #include <asm/page_32.h>
 243 #endif
 244
 245 /* align addr on a size boundary - adjust address up/down if needed */
 246 #define _ALIGN_UP(addr, size)   __ALIGN_KERNEL(addr, size)
 247 #define _ALIGN_DOWN(addr, size) ((addr)&(~((typeof(addr))(size)-1)))
 248
 249 /* align addr on a size boundary - adjust address up if needed */
 250 #define _ALIGN(addr,size)     _ALIGN_UP(addr,size)
 251
 252 /*
 253  * Don't compare things with KERNELBASE or PAGE_OFFSET to test for
 254  * "kernelness", use is_kernel_addr() - it should do what you want.
 255  */
 256 #ifdef CONFIG_PPC_BOOK3E_64
 257 #define is_kernel_addr(x)       ((x) >= 0x8000000000000000ul)
 258 #else
 259 #define is_kernel_addr(x)       ((x) >= PAGE_OFFSET)
 260 #endif
 261
 262 #ifndef CONFIG_PPC_BOOK3S_64
 263 /*
 264  * Use the top bit of the higher-level page table entries to indicate whether
 265  * the entries we point to contain hugepages.  This works because we know that
 266  * the page tables live in kernel space.  If we ever decide to support having
 267  * page tables at arbitrary addresses, this breaks and will have to change.
 268  */
 269 #ifdef CONFIG_PPC64
 270 #define PD_HUGE 0x8000000000000000
 271 #else
 272 #define PD_HUGE 0x80000000
 273 #endif
 274
 275 #else   /* CONFIG_PPC_BOOK3S_64 */
 276 /*
 277  * Book3S 64 stores real addresses in the hugepd entries to
 278  * avoid overlaps with _PAGE_PRESENT and _PAGE_PTE.
 279  */
 280 #define HUGEPD_ADDR_MASK        (0x0ffffffffffffffful & ~HUGEPD_SHIFT_MASK)
 281 #endif /* CONFIG_PPC_BOOK3S_64 */
 282
 283 /*
 284  * Some number of bits at the level of the page table that points to
 285  * a hugepte are used to encode the size.  This masks those bits.
 286  */
 287 #define HUGEPD_SHIFT_MASK     0x3f
 288
 289 #ifndef __ASSEMBLY__
 290
 291 #ifdef CONFIG_PPC_BOOK3S_64
 292 #include <asm/pgtable-be-types.h>
 293 #else
 294 #include <asm/pgtable-types.h>
 295 #endif
 296
 297
 298 #ifndef CONFIG_HUGETLB_PAGE
 299 #define is_hugepd(pdep)         (0)
 300 #define pgd_huge(pgd)           (0)
 301 #endif /* CONFIG_HUGETLB_PAGE */
 302
 303 struct page;
 304 extern void clear_user_page(void *page, unsigned long vaddr, struct page *pg);
 305 extern void copy_user_page(void *to, void *from, unsigned long vaddr,
 306                 struct page *p);
 307 extern int page_is_ram(unsigned long pfn);
 308 extern int devmem_is_allowed(unsigned long pfn);
 309
 310 #ifdef CONFIG_PPC_SMLPAR
 311 void arch_free_page(struct page *page, int order);
 312 #define HAVE_ARCH_FREE_PAGE
 313 #endif
 314
 315 struct vm_area_struct;
 316 #ifdef CONFIG_PPC_BOOK3S_64
 317 /*
 318  * For BOOK3s 64 with 4k and 64K linux page size
 319  * we want to use pointers, because the page table
 320  * actually store pfn
 321  */
 322 typedef pte_t *pgtable_t;
 323 #else
 324 #if defined(CONFIG_PPC_64K_PAGES) && defined(CONFIG_PPC64)
 325 typedef pte_t *pgtable_t;
 326 #else
 327 typedef struct page *pgtable_t;
 328 #endif
 329 #endif
 330
 331 #include <asm-generic/memory_model.h>
 332 #endif /* __ASSEMBLY__ */
 333
 334 #endif /* _ASM_POWERPC_PAGE_H */