arch/powerpc/include/asm/page.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 #ifndef _ASM_POWERPC_PAGE_H
   3 #define _ASM_POWERPC_PAGE_H
   4
   5 /*
   6  * Copyright (C) 2001,2005 IBM Corporation.
   7  */
   8
   9 #ifndef __ASSEMBLY__
  10 #include <linux/types.h>
  11 #include <linux/kernel.h>
  12 #else
  13 #include <asm/types.h>
  14 #endif
  15 #include <asm/asm-const.h>
  16
  17 /*
  18  * On regular PPC32 page size is 4K (but we support 4K/16K/64K/256K pages
  19  * on PPC44x and 4K/16K on 8xx). For PPC64 we support either 4K or 64K software
  20  * page size. When using 64K pages however, whether we are really supporting
  21  * 64K pages in HW or not is irrelevant to those definitions.
  22  */
  23 #define PAGE_SHIFT              CONFIG_PPC_PAGE_SHIFT
  24 #define PAGE_SIZE               (ASM_CONST(1) << PAGE_SHIFT)
  25
  26 #ifndef __ASSEMBLY__
  27 #ifndef CONFIG_HUGETLB_PAGE
  28 #define HPAGE_SHIFT PAGE_SHIFT
  29 #elif defined(CONFIG_PPC_BOOK3S_64)
  30 extern unsigned int hpage_shift;
  31 #define HPAGE_SHIFT hpage_shift
  32 #elif defined(CONFIG_PPC_8xx)
  33 #define HPAGE_SHIFT             19      /* 512k pages */
  34 #elif defined(CONFIG_PPC_FSL_BOOK3E)
  35 #define HPAGE_SHIFT             22      /* 4M pages */
  36 #endif
  37 #define HPAGE_SIZE              ((1UL) << HPAGE_SHIFT)
  38 #define HPAGE_MASK              (~(HPAGE_SIZE - 1))
  39 #define HUGETLB_PAGE_ORDER      (HPAGE_SHIFT - PAGE_SHIFT)
  40 #define HUGE_MAX_HSTATE         (MMU_PAGE_COUNT-1)
  41 #endif
  42
  43 /*
  44  * Subtle: (1 << PAGE_SHIFT) is an int, not an unsigned long. So if we
  45  * assign PAGE_MASK to a larger type it gets extended the way we want
  46  * (i.e. with 1s in the high bits)
  47  */
  48 #define PAGE_MASK      (~((1 << PAGE_SHIFT) - 1))
  49
  50 /*
  51  * KERNELBASE is the virtual address of the start of the kernel, it's often
  52  * the same as PAGE_OFFSET, but _might not be_.
  53  *
  54  * The kdump dump kernel is one example where KERNELBASE != PAGE_OFFSET.
  55  *
  56  * PAGE_OFFSET is the virtual address of the start of lowmem.
  57  *
  58  * PHYSICAL_START is the physical address of the start of the kernel.
  59  *
  60  * MEMORY_START is the physical address of the start of lowmem.
  61  *
  62  * KERNELBASE, PAGE_OFFSET, and PHYSICAL_START are all configurable on
  63  * ppc32 and based on how they are set we determine MEMORY_START.
  64  *
  65  * For the linear mapping the following equation should be true:
  66  * KERNELBASE - PAGE_OFFSET = PHYSICAL_START - MEMORY_START
  67  *
  68  * Also, KERNELBASE >= PAGE_OFFSET and PHYSICAL_START >= MEMORY_START
  69  *
  70  * There are two ways to determine a physical address from a virtual one:
  71  * va = pa + PAGE_OFFSET - MEMORY_START
  72  * va = pa + KERNELBASE - PHYSICAL_START
  73  *
  74  * If you want to know something's offset from the start of the kernel you
  75  * should subtract KERNELBASE.
  76  *
  77  * If you want to test if something's a kernel address, use is_kernel_addr().
  78  */
  79
  80 #define KERNELBASE      ASM_CONST(CONFIG_KERNEL_START)
  81 #define PAGE_OFFSET     ASM_CONST(CONFIG_PAGE_OFFSET)
  82 #define LOAD_OFFSET     ASM_CONST((CONFIG_KERNEL_START-CONFIG_PHYSICAL_START))
  83
  84 #if defined(CONFIG_NONSTATIC_KERNEL)
  85 #ifndef __ASSEMBLY__
  86
  87 extern phys_addr_t memstart_addr;
  88 extern phys_addr_t kernstart_addr;
  89
  90 #if defined(CONFIG_RELOCATABLE) && defined(CONFIG_PPC32)
  91 extern long long virt_phys_offset;
  92 #endif
  93
  94 #endif /* __ASSEMBLY__ */
  95 #define PHYSICAL_START  kernstart_addr
  96
  97 #else   /* !CONFIG_NONSTATIC_KERNEL */
  98 #define PHYSICAL_START  ASM_CONST(CONFIG_PHYSICAL_START)
  99 #endif
 100
 101 /* See Description below for VIRT_PHYS_OFFSET */
 102 #if defined(CONFIG_PPC32) && defined(CONFIG_BOOKE)
 103 #ifdef CONFIG_RELOCATABLE
 104 #define VIRT_PHYS_OFFSET virt_phys_offset
 105 #else
 106 #define VIRT_PHYS_OFFSET (KERNELBASE - PHYSICAL_START)
 107 #endif
 108 #endif
 109
 110 #ifdef CONFIG_PPC64
 111 #define MEMORY_START    0UL
 112 #elif defined(CONFIG_NONSTATIC_KERNEL)
 113 #define MEMORY_START    memstart_addr
 114 #else
 115 #define MEMORY_START    (PHYSICAL_START + PAGE_OFFSET - KERNELBASE)
 116 #endif
 117
 118 #ifdef CONFIG_FLATMEM
 119 #define ARCH_PFN_OFFSET         ((unsigned long)(MEMORY_START >> PAGE_SHIFT))
 120 #ifndef __ASSEMBLY__
 121 extern unsigned long max_mapnr;
 122 static inline bool pfn_valid(unsigned long pfn)
 123 {
 124         unsigned long min_pfn = ARCH_PFN_OFFSET;
 125
 126         return pfn >= min_pfn && pfn < max_mapnr;
 127 }
 128 #endif
 129 #endif
 130
 131 #define virt_to_pfn(kaddr)      (__pa(kaddr) >> PAGE_SHIFT)
 132 #define virt_to_page(kaddr)     pfn_to_page(virt_to_pfn(kaddr))
 133 #define pfn_to_kaddr(pfn)       __va((pfn) << PAGE_SHIFT)
 134
 135 #define virt_addr_valid(vaddr)  ({                                      \
 136         unsigned long _addr = (unsigned long)vaddr;                     \
 137         _addr >= PAGE_OFFSET && _addr < (unsigned long)high_memory &&   \
 138         pfn_valid(virt_to_pfn(_addr));                                  \
 139 })
 140
 141 /*
 142  * On Book-E parts we need __va to parse the device tree and we can't
 143  * determine MEMORY_START until then.  However we can determine PHYSICAL_START
 144  * from information at hand (program counter, TLB lookup).
 145  *
 146  * On BookE with RELOCATABLE && PPC32
 147  *
 148  *   With RELOCATABLE && PPC32,  we support loading the kernel at any physical
 149  *   address without any restriction on the page alignment.
 150  *
 151  *   We find the runtime address of _stext and relocate ourselves based on
 152  *   the following calculation:
 153  *
 154  *        virtual_base = ALIGN_DOWN(KERNELBASE,256M) +
 155  *                              MODULO(_stext.run,256M)
 156  *   and create the following mapping:
 157  *
 158  *        ALIGN_DOWN(_stext.run,256M) => ALIGN_DOWN(KERNELBASE,256M)
 159  *
 160  *   When we process relocations, we cannot depend on the
 161  *   existing equation for the __va()/__pa() translations:
 162  *
 163  *         __va(x) = (x)  - PHYSICAL_START + KERNELBASE
 164  *
 165  *   Where:
 166  *       PHYSICAL_START = kernstart_addr = Physical address of _stext
 167  *       KERNELBASE = Compiled virtual address of _stext.
 168  *
 169  *   This formula holds true iff, kernel load address is TLB page aligned.
 170  *
 171  *   In our case, we need to also account for the shift in the kernel Virtual
 172  *   address.
 173  *
 174  *   E.g.,
 175  *
 176  *   Let the kernel be loaded at 64MB and KERNELBASE be 0xc0000000 (same as PAGE_OFFSET).
 177  *   In this case, we would be mapping 0 to 0xc0000000, and kernstart_addr = 64M
 178  *
 179  *   Now __va(1MB) = (0x100000) - (0x4000000) + 0xc0000000
 180  *                 = 0xbc100000 , which is wrong.
 181  *
 182  *   Rather, it should be : 0xc0000000 + 0x100000 = 0xc0100000
 183  *              according to our mapping.
 184  *
 185  *   Hence we use the following formula to get the translations right:
 186  *
 187  *        __va(x) = (x) - [ PHYSICAL_START - Effective KERNELBASE ]
 188  *
 189  *        Where :
 190  *              PHYSICAL_START = dynamic load address.(kernstart_addr variable)
 191  *              Effective KERNELBASE = virtual_base =
 192  *                                   = ALIGN_DOWN(KERNELBASE,256M) +
 193  *                                              MODULO(PHYSICAL_START,256M)
 194  *
 195  *      To make the cost of __va() / __pa() more light weight, we introduce
 196  *      a new variable virt_phys_offset, which will hold :
 197  *
 198  *      virt_phys_offset = Effective KERNELBASE - PHYSICAL_START
 199  *                       = ALIGN_DOWN(KERNELBASE,256M) -
 200  *                              ALIGN_DOWN(PHYSICALSTART,256M)
 201  *
 202  *      Hence :
 203  *
 204  *      __va(x) = x - PHYSICAL_START + Effective KERNELBASE
 205  *              = x + virt_phys_offset
 206  *
 207  *              and
 208  *      __pa(x) = x + PHYSICAL_START - Effective KERNELBASE
 209  *              = x - virt_phys_offset
 210  *
 211  * On non-Book-E PPC64 PAGE_OFFSET and MEMORY_START are constants so use
 212  * the other definitions for __va & __pa.
 213  */
 214 #if defined(CONFIG_PPC32) && defined(CONFIG_BOOKE)
 215 #define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + VIRT_PHYS_OFFSET))
 216 #define __pa(x) ((phys_addr_t)(unsigned long)(x) - VIRT_PHYS_OFFSET)
 217 #else
 218 #ifdef CONFIG_PPC64
 219 /*
 220  * gcc miscompiles (unsigned long)(&static_var) - PAGE_OFFSET
 221  * with -mcmodel=medium, so we use & and | instead of - and + on 64-bit.
 222  * This also results in better code generation.
 223  */
 224 #define __va(x)                                                         \
 225 ({                                                                      \
 226         VIRTUAL_BUG_ON((unsigned long)(x) >= PAGE_OFFSET);              \
 227         (void *)(unsigned long)((phys_addr_t)(x) | PAGE_OFFSET);        \
 228 })
 229
 230 #define __pa(x)                                                         \
 231 ({                                                                      \
 232         VIRTUAL_BUG_ON((unsigned long)(x) < PAGE_OFFSET);               \
 233         (unsigned long)(x) & 0x0fffffffffffffffUL;                      \
 234 })
 235
 236 #else /* 32-bit, non book E */
 237 #define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + PAGE_OFFSET - MEMORY_START))
 238 #define __pa(x) ((unsigned long)(x) - PAGE_OFFSET + MEMORY_START)
 239 #endif
 240 #endif
 241
 242 /*
 243  * Unfortunately the PLT is in the BSS in the PPC32 ELF ABI,
 244  * and needs to be executable.  This means the whole heap ends
 245  * up being executable.
 246  */
 247 #define VM_DATA_DEFAULT_FLAGS32 VM_DATA_FLAGS_TSK_EXEC
 248 #define VM_DATA_DEFAULT_FLAGS64 VM_DATA_FLAGS_NON_EXEC
 249
 250 #ifdef __powerpc64__
 251 #include <asm/page_64.h>
 252 #else
 253 #include <asm/page_32.h>
 254 #endif
 255
 256 /*
 257  * Don't compare things with KERNELBASE or PAGE_OFFSET to test for
 258  * "kernelness", use is_kernel_addr() - it should do what you want.
 259  */
 260 #ifdef CONFIG_PPC_BOOK3E_64
 261 #define is_kernel_addr(x)       ((x) >= 0x8000000000000000ul)
 262 #elif defined(CONFIG_PPC_BOOK3S_64)
 263 #define is_kernel_addr(x)       ((x) >= PAGE_OFFSET)
 264 #else
 265 #define is_kernel_addr(x)       ((x) >= TASK_SIZE)
 266 #endif
 267
 268 #ifndef CONFIG_PPC_BOOK3S_64
 269 /*
 270  * Use the top bit of the higher-level page table entries to indicate whether
 271  * the entries we point to contain hugepages.  This works because we know that
 272  * the page tables live in kernel space.  If we ever decide to support having
 273  * page tables at arbitrary addresses, this breaks and will have to change.
 274  */
 275 #ifdef CONFIG_PPC64
 276 #define PD_HUGE 0x8000000000000000UL
 277 #else
 278 #define PD_HUGE 0x80000000
 279 #endif
 280
 281 #else   /* CONFIG_PPC_BOOK3S_64 */
 282 /*
 283  * Book3S 64 stores real addresses in the hugepd entries to
 284  * avoid overlaps with _PAGE_PRESENT and _PAGE_PTE.
 285  */
 286 #define HUGEPD_ADDR_MASK        (0x0ffffffffffffffful & ~HUGEPD_SHIFT_MASK)
 287 #endif /* CONFIG_PPC_BOOK3S_64 */
 288
 289 /*
 290  * Some number of bits at the level of the page table that points to
 291  * a hugepte are used to encode the size.  This masks those bits.
 292  * On 8xx, HW assistance requires 4k alignment for the hugepte.
 293  */
 294 #ifdef CONFIG_PPC_8xx
 295 #define HUGEPD_SHIFT_MASK     0xfff
 296 #else
 297 #define HUGEPD_SHIFT_MASK     0x3f
 298 #endif
 299
 300 #ifndef __ASSEMBLY__
 301
 302 #ifdef CONFIG_PPC_BOOK3S_64
 303 #include <asm/pgtable-be-types.h>
 304 #else
 305 #include <asm/pgtable-types.h>
 306 #endif
 307
 308
 309 #ifndef CONFIG_HUGETLB_PAGE
 310 #define is_hugepd(pdep)         (0)
 311 #define pgd_huge(pgd)           (0)
 312 #endif /* CONFIG_HUGETLB_PAGE */
 313
 314 struct page;
 315 extern void clear_user_page(void *page, unsigned long vaddr, struct page *pg);
 316 extern void copy_user_page(void *to, void *from, unsigned long vaddr,
 317                 struct page *p);
 318 extern int devmem_is_allowed(unsigned long pfn);
 319
 320 #ifdef CONFIG_PPC_SMLPAR
 321 void arch_free_page(struct page *page, int order);
 322 #define HAVE_ARCH_FREE_PAGE
 323 #endif
 324
 325 struct vm_area_struct;
 326
 327 extern unsigned long kernstart_virt_addr;
 328
 329 static inline unsigned long kaslr_offset(void)
 330 {
 331         return kernstart_virt_addr - KERNELBASE;
 332 }
 333
 334 #include <asm-generic/memory_model.h>
 335 #endif /* __ASSEMBLY__ */
 336 #include <asm/slice.h>
 337
 338 #endif /* _ASM_POWERPC_PAGE_H */