osfmk/mach/vm_param.h

   1 /*
   2  * Copyright (c) 2000-2006 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
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   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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  23  * Please see the License for the specific language governing rights and
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  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * @OSF_COPYRIGHT@
  30  */
  31 /*
  32  * Mach Operating System
  33  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  34  * All Rights Reserved.
  35  *
  36  * Permission to use, copy, modify and distribute this software and its
  37  * documentation is hereby granted, provided that both the copyright
  38  * notice and this permission notice appear in all copies of the
  39  * software, derivative works or modified versions, and any portions
  40  * thereof, and that both notices appear in supporting documentation.
  41  *
  42  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  43  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  44  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  45  *
  46  * Carnegie Mellon requests users of this software to return to
  47  *
  48  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  49  *  School of Computer Science
  50  *  Carnegie Mellon University
  51  *  Pittsburgh PA 15213-3890
  52  *
  53  * any improvements or extensions that they make and grant Carnegie Mellon
  54  * the rights to redistribute these changes.
  55  */
  56 /*
  57  */
  58 /*
  59  *      File:   mach/vm_param.h
  60  *      Author: Avadis Tevanian, Jr., Michael Wayne Young
  61  *      Date:   1985
  62  *
  63  *      Machine independent virtual memory parameters.
  64  *
  65  */
  66
  67 #ifndef _MACH_VM_PARAM_H_
  68 #define _MACH_VM_PARAM_H_
  69
  70 #include <mach/machine/vm_param.h>
  71
  72 #ifdef  KERNEL
  73
  74 #ifndef ASSEMBLER
  75 #include <mach/vm_types.h>
  76 #endif  /* ASSEMBLER */
  77
  78 /*
  79  *      The machine independent pages are refered to as PAGES.  A page
  80  *      is some number of hardware pages, depending on the target machine.
  81  */
  82
  83 #ifndef ASSEMBLER
  84
  85 #define PAGE_SIZE_64 (unsigned long long)PAGE_SIZE              /* pagesize in addr units */
  86 #define PAGE_MASK_64 (unsigned long long)PAGE_MASK              /* mask for off in page */
  87
  88 /*
  89  *      Convert addresses to pages and vice versa.  No rounding is used.
  90  *      The atop_32 and ptoa_32 macros should not be use on 64 bit types.
  91  *      The round_page_64 and trunc_page_64 macros should be used instead.
  92  */
  93
  94 #define atop_32(x) ((uint32_t)(x) >> PAGE_SHIFT)
  95 #define ptoa_32(x) ((uint32_t)(x) << PAGE_SHIFT)
  96 #define atop_64(x) ((uint64_t)(x) >> PAGE_SHIFT)
  97 #define ptoa_64(x) ((uint64_t)(x) << PAGE_SHIFT)
  98
  99 #define atop_kernel(x) ((vm_address_t)(x) >> PAGE_SHIFT)
 100 #define ptoa_kernel(x) ((vm_address_t)(x) << PAGE_SHIFT)
 101
 102 /*
 103  *      While the following block is enabled, the legacy atop and ptoa
 104  *      macros will behave correctly.  If not, they will generate
 105  *      invalid lvalue errors.
 106  */
 107
 108 #if 1
 109 #define atop(x) ((vm_address_t)(x) >> PAGE_SHIFT)
 110 #define ptoa(x) ((vm_address_t)(x) << PAGE_SHIFT)
 111 #else
 112 #define atop(x) (0UL = 0)
 113 #define ptoa(x) (0UL = 0)
 114 #endif
 115
 116 /*
 117  *      Page-size rounding macros for the Public fixed-width VM types.
 118  */
 119 #define mach_vm_round_page(x) (((mach_vm_offset_t)(x) + PAGE_MASK) & ~((signed)PAGE_MASK))
 120 #define mach_vm_trunc_page(x) ((mach_vm_offset_t)(x) & ~((signed)PAGE_MASK))
 121
 122 #define memory_object_round_page(x) (((memory_object_offset_t)(x) + PAGE_MASK) & ~((signed)PAGE_MASK))
 123 #define memory_object_trunc_page(x) ((memory_object_offset_t)(x) & ~((signed)PAGE_MASK))
 124
 125 /*
 126  *      Rounding macros for the legacy (scalable with the current task's
 127  *      address space size) VM types.
 128  */
 129
 130 #define round_page(x) (((vm_offset_t)(x) + PAGE_MASK) & ~((vm_offset_t)PAGE_MASK))
 131 #define trunc_page(x) ((vm_offset_t)(x) & ~((vm_offset_t)PAGE_MASK))
 132
 133 /*
 134  *      Round off or truncate to the nearest page.  These will work
 135  *      for either addresses or counts.  (i.e. 1 byte rounds to 1 page
 136  *      bytes.  The round_page_32 and trunc_page_32 macros should not be
 137  *      use on 64 bit types.  The round_page_64 and trunc_page_64 macros
 138  *      should be used instead.
 139  *
 140  *      These should only be used in the rare case the size of the address
 141  *      or length is hard-coded as 32 or 64 bit.  Otherwise, the macros
 142  *      associated with the specific VM type should be used.
 143  */
 144
 145 #define round_page_32(x) (((uint32_t)(x) + PAGE_MASK) & ~((uint32_t)PAGE_MASK))
 146 #define trunc_page_32(x) ((uint32_t)(x) & ~((uint32_t)PAGE_MASK))
 147 #define round_page_64(x) (((uint64_t)(x) + PAGE_MASK_64) & ~((uint64_t)PAGE_MASK_64))
 148 #define trunc_page_64(x) ((uint64_t)(x) & ~((uint64_t)PAGE_MASK_64))
 149
 150 /*
 151  *      Enable the following block to find uses of xxx_32 macros that should
 152  *      be xxx_64.  These macros only work in C code, not C++.  The resulting
 153  *      binaries are not functional.  Look for invalid lvalue errors in
 154  *      the compiler output.
 155  *
 156  *      Enabling the following block will also find use of the xxx_64 macros
 157  *      that have been passed pointers.  The parameters should be case to an
 158  *      unsigned long type first.  Look for invalid operands to binary + error
 159  *      in the compiler output.
 160  */
 161
 162 #if 0
 163 #undef atop_32
 164 #undef ptoa_32
 165 #undef round_page_32
 166 #undef trunc_page_32
 167 #undef atop_64
 168 #undef ptoa_64
 169 #undef round_page_64
 170 #undef trunc_page_64
 171
 172 #ifndef __cplusplus
 173
 174 #define atop_32(x) \
 175     (__builtin_choose_expr (sizeof(x) != sizeof(uint64_t), \
 176         (*(long *)0), \
 177         (0UL)) = 0)
 178
 179 #define ptoa_32(x) \
 180     (__builtin_choose_expr (sizeof(x) != sizeof(uint64_t), \
 181         (*(long *)0), \
 182         (0UL)) = 0)
 183
 184 #define round_page_32(x) \
 185     (__builtin_choose_expr (sizeof(x) != sizeof(uint64_t), \
 186         (*(long *)0), \
 187         (0UL)) = 0)
 188
 189 #define trunc_page_32(x) \
 190     (__builtin_choose_expr (sizeof(x) != sizeof(uint64_t), \
 191         (*(long *)0), \
 192         (0UL)) = 0)
 193 #else
 194
 195 #define atop_32(x) (0)
 196 #define ptoa_32(x) (0)
 197 #define round_page_32(x) (0)
 198 #define trunc_page_32(x) (0)
 199
 200 #endif /* ! __cplusplus */
 201
 202 #define atop_64(x) ((uint64_t)((x) + (uint8_t *)0))
 203 #define ptoa_64(x) ((uint64_t)((x) + (uint8_t *)0))
 204 #define round_page_64(x) ((uint64_t)((x) + (uint8_t *)0))
 205 #define trunc_page_64(x) ((uint64_t)((x) + (uint8_t *)0))
 206
 207 #endif
 208
 209 /*
 210  *      Determine whether an address is page-aligned, or a count is
 211  *      an exact page multiple.
 212  */
 213
 214 #define page_aligned(x) (((x) & PAGE_MASK) == 0)
 215
 216 extern vm_size_t        mem_size;               /* 32-bit size of memory - limited by maxmem - deprecated */
 217 extern uint64_t         max_mem;                /* 64-bit size of memory - limited by maxmem */
 218
 219 /*
 220  * The default pager does not handle 64-bit offsets inside its objects,
 221  * so this limits the size of anonymous memory objects to 4GB minus 1 page.
 222  * When we need to allocate a chunk of anonymous memory over that size,
 223  * we have to allocate more than one chunk.
 224  */
 225 #define ANON_MAX_SIZE   0xFFFFF000ULL
 226 /*
 227  * Work-around for <rdar://problem/6626493>
 228  * Break large anonymous memory areas into 128MB chunks to alleviate
 229  * the cost of copying when copy-on-write is not possible because a small
 230  * portion of it being wired.
 231  */
 232 #define ANON_CHUNK_SIZE (128ULL * 1024 * 1024) /* 128MB */
 233
 234 #ifdef  XNU_KERNEL_PRIVATE
 235
 236 extern uint64_t         mem_actual;             /* 64-bit size of memory - not limited by maxmem */
 237 extern uint64_t         sane_size;              /* Memory size to use for defaults calculations */
 238 extern addr64_t         vm_last_addr;   /* Highest kernel virtual address known to the VM system */
 239
 240 extern const vm_offset_t        vm_min_kernel_address;
 241 extern const vm_offset_t        vm_max_kernel_address;
 242
 243 extern vm_offset_t              vm_kernel_stext;
 244 extern vm_offset_t              vm_kernel_etext;
 245 extern vm_offset_t              vm_kernel_base;
 246 extern vm_offset_t              vm_kernel_top;
 247 extern vm_offset_t              vm_kernel_slide;
 248 extern vm_offset_t              vm_hib_base;
 249 extern vm_offset_t              vm_kernel_addrperm;
 250
 251 extern vm_offset_t              vm_kext_base;
 252 extern vm_offset_t              vm_kext_top;
 253 extern vm_offset_t      vm_prelink_stext;
 254 extern vm_offset_t      vm_prelink_etext;
 255 extern vm_offset_t      vm_prelink_sinfo;
 256 extern vm_offset_t      vm_prelink_einfo;
 257 extern vm_offset_t      vm_slinkedit;
 258 extern vm_offset_t      vm_elinkedit;
 259
 260 #define VM_KERNEL_IS_SLID(_o)                                                  \
 261                 (((vm_offset_t)(_o) >= vm_kernel_base) &&                      \
 262                  ((vm_offset_t)(_o) <=  vm_kernel_top))
 263 #define VM_KERNEL_IS_KEXT(_o)                                                  \
 264                 (((vm_offset_t)(_o) >= vm_kext_base) &&                        \
 265                  ((vm_offset_t)(_o) <  vm_kext_top))
 266
 267 #define VM_KERNEL_IS_PRELINKTEXT(_o)        \
 268         (((vm_offset_t)(_o) >= vm_prelink_stext) &&     \
 269          ((vm_offset_t)(_o) <  vm_prelink_etext))
 270
 271 #define VM_KERNEL_IS_PRELINKINFO(_o)        \
 272         (((vm_offset_t)(_o) >= vm_prelink_sinfo) &&     \
 273          ((vm_offset_t)(_o) <  vm_prelink_einfo))
 274
 275 #define VM_KERNEL_IS_KEXT_LINKEDIT(_o)        \
 276         (((vm_offset_t)(_o) >= vm_slinkedit) &&     \
 277          ((vm_offset_t)(_o) <  vm_elinkedit))
 278
 279 #define VM_KERNEL_SLIDE(_u)                                                    \
 280                 ((vm_offset_t)(_u) + vm_kernel_slide)
 281
 282 /*
 283  * The following macros are to be used when exposing kernel addresses to
 284  * userspace via any of the various debug or info facilities that might exist
 285  * (e.g. stackshot, proc_info syscall, etc.). It is important to understand
 286  * the goal of each macro and choose the right one depending on what you are
 287  * trying to do. Misuse of these macros can result in critical data leaks
 288  * which in turn lead to all sorts of system vulnerabilities.
 289  *
 290  * Note that in general the ideal goal is to protect addresses from userspace
 291  * in a way that is reversible assuming you know the permutation and/or slide.
 292  *
 293  * The macros are as follows:
 294  *
 295  * VM_KERNEL_UNSLIDE:
 296  *     Use this macro when you are exposing an address to userspace which is
 297  *     a "static" kernel or kext address (i.e. coming from text or data
 298  *     sections). These are the addresses which get "slid" via ASLR on kernel
 299  *     or kext load, and it's precisely the slide value we are trying to
 300  *     protect from userspace.
 301  *
 302  * VM_KERNEL_ADDRPERM:
 303  *     Use this macro when you are exposing an address to userspace which is
 304  *     coming from the kernel's "heap". Since these adresses are not "loaded"
 305  *     from anywhere, there is no slide applied and we instead apply the
 306  *     permutation value to obscure the address.
 307  *
 308  * VM_KERNEL_UNSLIDE_OR_ADDRPERM:
 309  *     Use this macro when you are exposing an address to userspace that could
 310  *     come from either kernel text/data *or* the heap. This is a rare case,
 311  *     but one that does come up and must be handled correctly.
 312  *
 313  * Nesting of these macros should be considered invalid.
 314  */
 315 #define VM_KERNEL_UNSLIDE(_v)                                                  \
 316                 ((VM_KERNEL_IS_SLID(_v) ||                                     \
 317           VM_KERNEL_IS_KEXT(_v) ||      \
 318           VM_KERNEL_IS_PRELINKTEXT(_v) ||   \
 319           VM_KERNEL_IS_PRELINKINFO(_v) ||   \
 320           VM_KERNEL_IS_KEXT_LINKEDIT(_v)) ?     \
 321                         (vm_offset_t)(_v) - vm_kernel_slide :                  \
 322                         (vm_offset_t)(_v))
 323
 324 #define VM_KERNEL_ADDRPERM(_v)                                                 \
 325                 (((vm_offset_t)(_v) == 0) ?                                    \
 326                         (vm_offset_t)(0) :                                     \
 327                         (vm_offset_t)(_v) + vm_kernel_addrperm)
 328
 329 #define VM_KERNEL_UNSLIDE_OR_PERM(_v)                                          \
 330                 ((VM_KERNEL_IS_SLID(_v) ||                                     \
 331           VM_KERNEL_IS_KEXT(_v) ||      \
 332           VM_KERNEL_IS_PRELINKTEXT(_v) ||   \
 333           VM_KERNEL_IS_PRELINKINFO(_v) ||   \
 334           VM_KERNEL_IS_KEXT_LINKEDIT(_v)) ?     \
 335                         (vm_offset_t)(_v) - vm_kernel_slide :                  \
 336                         VM_KERNEL_ADDRPERM(_v))
 337
 338
 339 #endif  /* XNU_KERNEL_PRIVATE */
 340
 341 extern vm_size_t        page_size;
 342 extern vm_size_t        page_mask;
 343 extern int              page_shift;
 344
 345 /* We need a way to get rid of compiler warnings when we cast from   */
 346 /* a 64 bit value to an address (which may be 32 bits or 64-bits).   */
 347 /* An intptr_t is used convert the value to the right precision, and */
 348 /* then to an address. This macro is also used to convert addresses  */
 349 /* to 32-bit integers, which is a hard failure for a 64-bit kernel   */
 350 #include <stdint.h>
 351 #ifndef __CAST_DOWN_CHECK
 352 #define __CAST_DOWN_CHECK
 353
 354 #define CAST_DOWN( type, addr ) \
 355     ( ((type)((uintptr_t) (addr)/(sizeof(type) < sizeof(uintptr_t) ? 0 : 1))) )
 356
 357 #define CAST_DOWN_EXPLICIT( type, addr )  ( ((type)((uintptr_t) (addr))) )
 358
 359 #endif /* __CAST_DOWN_CHECK */
 360
 361 #endif  /* ASSEMBLER */
 362
 363 #endif  /* KERNEL */
 364
 365 #endif  /* _MACH_VM_PARAM_H_ */